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water

Volume 30 No 2 March 2003 Jou rn al of the Australian Wat er Association

Editorial Board F R Bish o p , C h airma n l3 N Anderson, R. Considine, W J l)ulfer, G Finke, G Finlayson. G A H older. l3 Labza. M Muntisov, I' Nadcbau111, J I) Parker, J ll..issrnan . F ll..oddick, G rt yan, S Gray •, I l' aicr is a refereed journal. This sym bol

CONTENTS OPINION 2

indicates that a paper has been refereed .

Parting Words; One Vision; Aquaphemera; Our Rights; My Point of View, Science Versus Business?; Whose Water Is It Anyway?

ASSOCIATION ACTIVITIES

Submissions In structions for authors can be found 011 page 1-1 of this journal. Sub111i1sions accepted at: www .a wa .asn .au/ pu bl icati ons/

16

PROFESSIONAL DEVELOPMENT 18

Managing Editor

Including AIWA and WEF Reports Details of courses, classes and other upcoming water events

NEWS BYTES

P eter Stirling

News and Supervising Editor

20

Featuring selected highlights from the AWA email News

Brian M cRa e A WA T echnica l Di rector Tel: (02) 9413 1288 Fax: (02) 9.\13 1047 E111ail: bn1crac@awa .asn.au

CROSSCURRENT

Technical Editor

CONFERENCE REPORTS

E A (Bo b ) Swinton -l Pleasant View Cre1, Wheelers Hill Vic 3150 T d / Fax (03) 9560 .\752 Email: bswinron@ bigpond.net.au

29

Water Production

38

Hallmark E di tio n s l'O l3ox 8-l, H a111pron, Vic 3 I 88 Level I, 99 l3ay Street, 13righton, Vic 3186 Tel (03) 9530 8900 Fax (03) 9530 89 1 I E111ai l: hall111ark@halledic.co111.au

SPECIAL FEATURE: PIPELINES

24

42

Australian Water Association PO 13ox 388, Arrannon, NSW 1570 Tel +6 1 2 9-l 13 1288 Fax: (02) 94 13 I 0-l7 Email : info@awa.asn.au Al3N 78 096 035 773

AWA

Federal President Barry N o rman

Executive Director Chris Davis

~

AUSTRA LI AN WATER ASSOCIATION

Australian Water Association (A WA) ass umes no responsibility for opinions or statements of facts expressed by contributors o r advertise rs. Editorials do nor necessarily represent official A WA policy. Advertisements arc included as an information service to readers and arc reviewed before publication to ensure relevance to rhe water environment and objectives of AW A. All material in Wmcr is copyright and should not be reproduced wholly or in parr withou t rhe written permission of the Managing Editor.

°' CRITICAL WATER MAINS - THE NEED FOR RISK ANALYSIS Sydney Water's thirty year capital and operating investment program ·, SOILS INFORMATION BY GIS FOR IN-GROUND ASSET ANALYSIS Archival soil maps can be encapsulated in spatial and attribute databases I Alla n, R va n de Graaff

57

Water (ISSN 0310 · 0367) is published eig ht ri111c1 a year in the rnonr hs of February. March, May. J une, August, September, N ovember and D ecembe r.

Water: Aid That Works, D Jackson

R Radovanovic, A Marlin

48

Natio n al Sales M a nager: Brian R a ult T el (03) 9530 8900 Fax (03) 9530 8911 Mobile 04 11 354 050 Ernail: brault@halledit.com .a u

4th Australasian Water Law & Policy Conference B Mc Rae; Directions in Scientific Research B Mc Rae; CSIRO/AWA Seminar on Asset Management of Pipelines s Burn

INTERNATIONAL REPORT

G rap hic design : Mitz i Mann

Water Advertising

ACT Bushfires; 2003 National Competition Policy Assessment Framework; Barwon Water Sewer Mining Investigation; Serco' s Enterprise Resource Planning for Caliban Water

·, ASSESSMENT OF FERROUS PIPELINES: A NEW DEVELOPMENT Mains Assessment Probe (MAP) techniques for cost-effective pipeline assessment M Roubal

62

•, WHAT CAUSES CUSTOMER COMPLAINTS ABOUT DISCOLOURED DRINKING WATER? Correlating customer complaints with online monitoring of flow rate and turbidity RA Prince, I Coulter, G Ryan

68

SOME PIPELINES IN THE PIPELINE What's going on around the nation? Report by EA ( Bob) Swinton

ENVIRONMENT 76

•, PROTECTING STREAM HEALTH: A MANAGEMENT STRATEGY Stream health assessment for local government planning R Haase, P Loose, D Clowes, U Nolte

82

·, REDUCING NUTRIENT RELEASE FROM SEDIMENTS : ECOLOGICAL RISKS Assessing the risks associated with application of an active barrier

88

IMPROVING RIVER MANAGEMENT DURING DROUGHT Low flow (or dry) periods are as important as floods for Australian rivers

BT Han, S Robens, M O'Donohue, J Taylor, E Mcw illiam, M Waters

A Scott, S Lake, P Cott ingham, G Jo nes

WASTEWATER 92

', MONITORING BIOSOLIDS QUALITY: A STATISTICAL PERSPECTIVE Minimise the costs of sampling and testing, with respect to risks of error W L Pa ul, N S Barnett

Subscriptions

BUSINESS

I Vmer is sent to all AWA me111be1~ eight times a year. It is also av:iilable via subscription.

97

Visit the Water

PUBLIC AND PRIVATE OPTIONS IN AUSTRALIAN WATER MANAGEMENT Considerable scope for institutional reform remains P J Perkins 103 WATER PROPERTY RIGHTS A submission to COAG B McRae for th e Australian Water Association

HOME PAGE

and access news, calendars, bookshop and over 100 pages of information at

OUR COVER: The photo shows a pipe being laid by Syd11ey vVater i11 College Street i11 Syd11ey. Photo courtesy of the Sydn ey Water.

WATER MARCH 2003

1


FROM

THE

PRESIDENT

PARTING WORDS As I considered my last column as President, my starting point was my firs t co lumn, in April 2001, in which I spelt out some ambitions fo r my two years in the chair. I took a deep breath, knowing that reviewi ng promises and goals can be a sobering experience. Firstly, Corporate memberships have indeed been reviewed and are now offered in four steps from Bronze to Platinu m. This certainly seems to have worked and, with energetic sales efforts from M ichael Seller, are selling well. The multiple categories may require closer evaluation bu t response to date indicates the choice of packages on offer are worth the trouble of wrapping o ne's mind around their subtleties. The new TECHNOtours programme and the efforts to make our web offeri ngs more com mercial have got off to slow starts. Although our inaugural tour, to Sweden, Germany and The Netherlands, was lightly atte nded , the feed back from the small group that participated indicated it was very worthwhile. As I write, C lare Porter is hatching the Young Professionals TEC HNOtour for April and one to WE FTEC in October, - those events will show if the idea will end ure but I am hopeful of a bright future for the tours. In common with all web and internet operations, ours is no gold-nl.ine, but I feel it's increasing in depth and is earning a steady, although modest, income. An effective web site is a prerequisite for an Association like ours today, so we will continue to update and improve this inform ation portal over coming months. As promised, the Board has looked at individual memberships and has concluded from the membership survey and fo llow-up evaluation that there is little or n o demand for post-nomi n als. Concessional subscriptions w ill be rationalised though, to make life simpler. T he whole organisation is acutely aware of the need for an excellent value proposition fo r members, so that drives m uch of our thinking. My successor will, I know, be pursuing the growth and improved perform ance ofNational Special Interest Groups as a priority, given their potential to service niche interests effectively. Active and effective SI Gs rep resent a key service commitment on which future membership growth will be dependant. In an operational sense we have continued to adopt a more corporate approach to running the Association which has, in my view, benefited , the membership and staff alike and I am sure 2

WATER MARCH 2003

Barry Norman

will continue to strengthen the efficiency and scope of service to members. This has included a consolidated and consistent approach to accou nting and membership which has had the support of all B ranches, the outsourcing and improvement of "Water" and generally a more critica l assessment of where our effort is expended and the value delivered. The establishm ent of a Governance and Audit committee has also provided a valuable tool for reviewing our corporate governance responsibili ties associated w ith becoming a Company Limited by Guarantee. T h is is a further indication that the organisation continues to mature without losing an enthusiasm for tackling and embracing change. Another area where I have been extremely pleased to see the Association

water FUTURE MAJOR FEATURES JUNE Biosolids, Desludging Papers needed immediately. Articles April 8th AUGUST Reuse, Sustainability Papers April 8th. Articles May 3 0th. SEPTEMBER

Industrial Waste Treatment Papers May 30th. Articles July 11th.

NOVEMBER

Irrigation, Asset management, Economics Papers July 11th, Articles August 29th.

take a leading role is in the promotion of water and the environment to our next generation of wa t e r profess io nals . Through the Young Scientist of the Year Award, Australian J un ior Water Prize, U ndergrad uate Water Prize and the We All Use Water comm u nity education resourc es A WA is now taking th e sustainable management of water message beyond its traditional stakeholder base. These programmes are generally undertaken with corporate and utility member partners hel ping us create awareness not only of the water managem ent issues facing us today but to also raise AWA's profile as a valuable community resource. M ore recently we have been seeking proposals from Branches and members for projects that could be considered for funding from accumulated Reserves to furt her en hance those already entrain over to you for ideas! At both the Board and the smaller Executive Com m ittee level, we've been able to focus on the strategic direction of the Association and direct our energy and resources to those initiatives, w hich are key to our future. As a result, I believe AW A is healthier with a clearer vision of its direction and position in the Australian water scene. On re flection, I believe we have achieved many of our original objecti ves so perhaps the review has been less sobering than anticipated. Overall, I have thoroughly enjoyed my term as President and have considered it an honour and pleasure to serve the Association - thank you for the opportunity. I would like to pay tribute to Chris Davis and all AW A staff nationally who have offered fantastic support and encouragement to me over the past 2 years, to all Board and Executive Members and Branch Presidents who, as well as supporting me , have actively embraced many new directions and initiatives which will be the cornerstone of our development. Finally a particular thank you to Allen Gale and Neil Palmer who retire from the Executive in April after many years of committed service - their wise counsel will be missed - and a warm welcome to Peter Robinson and Carnl.ine Ciccicioppo - we look forward to their participation. Thank you again for the opportunity to serve the Association . Barry Norman


INTERNATIONAL

REPORT

WATER: AID THAT WORKS D Jackson There's a lot of skepticism about overseas aid. " How can we be sure that d evelopment assistance funds really reach poor communities, and make a difference in people's lives?" p eople ask. My recent monitoring visits to three water and sanitation projects in Kenya and Zambia reinforced my convi ction that, w hen strong community commitme nt is co mbined w ith ap pro p riate, wellresearched technologies, water aid really works. These three proj ects are funded by AusAID (the Australian Government Agency for International D evelop ment) , TEAR Australia (an Australian Christian development assistance organisation) and the local implementing partners and c ommunities. All three projects aim to re duce poverty and improve health and Jiving conditio ns, through the provision of safe water and better sanitation. This they do, but in very different ways. R esting firml y on a foundation of local ownership and participation, each project p artner and community has developed a different approach, and found different solutions to their water and sanitation needs. The story of their challenges and successes is an exciting example of w hat can be achieved, at relatively little cost, in bringing sustainable, long-term development.

ELDORET: A quick lesson in PHAST Eldoret district is in the west of Kenya, bordering on Uganda. One might wonder w hat a water engineer, was doing there. No weirs or dams, bores or pipelines. Not a pumping station in sight!

From the Executive Director:

At the time of writing, plans were b eing made to launch a water charity in Australia, probably co be called WaterAid Australia, modelled on the very successful WaterAid in the UK. The principles espoused in Darryl J ackso n's article are exactly those which are going to be taken up. A workshop is to be held in Perth, at the Burswood D ome, on Sunday 6 April. M embers interested in the project should contact C hris D avis on tel 02 94 1 3- 1 288 or e-mai l c davis@awa.asn.au

38

WATER MARCH 2003

~

SODIS is an accessible, non-chemical disinfection technology for villagers.

Instead, lots of groups. People, talking, laughing and learning together. These groups have been using a process called PHAST (Participatory H ygiene and Sanitation Transformation) to identify basic water and sanitation issues in their community, and to provide a framework fo r choosing and adopting the most appropriate technology interventio n for their context. Assisted by a trained facilitator, groups move through a series of exercises that demonstrate the relationship between hygiene, sanitation and health, empower them to plan environmental improvements, and develop the skills needed co own and operate water and sanitation facilities. Stephen Burgess, of the Anglican Church ofKenya's C hristian Community Services arm (the implementing partner) explained that the PHAST training built on previous experience in the project area. "Sanitation and hygiene lagged behind other advances," he said. "Diseases from dirty water and poor hygiene and sanitation were still maj or causes of sickness and death. We needed a way to change behaviour, before simply putting in new water and sanitation systems. PHAST provided a tool that worked ." Now, the groups are building over 400 water supply facilities (rainwater tanks, protected springs, protected shallow wells using rope and washer technology) and 360 improved pit latrines. The rope-andwasher wells are particularly interesting. This ancient Chinese technology has been

improved in Kenya and further developed by this proj ect. [t consists of a bicycle wheel over w hi ch a rope fitted with simple washers (made from old tyres) runs. This lifts water throu gh a 20mm PVC pipe at 20L per minute. Water depths vaty from 15 to 25 metres. A rop e-and-washer well avoids the use of a rope and bucket, which so easily contaminates water. It's cheap, easy to maintain, and is locally built. Interventions like this bring good water close to people's homes. Previously, women and children walked for ho urs a day to muddy rivers and springs to fetch the minimal amounts needed fo r survival. N ow, with improved water access and more time available, w omen are tending kitchen gardens, planting trees and taking pride in th e cleanliness of their children, clothes and homes. Bacteriological quality of water is being significantly improved using SOD IS (SOiar DISinfection). Now a widelyadopted develop m en t int er venti o n , SODIS uses solar radiation co disinfect water placed in clear PET bottles. The cost is minimal, the technology simple to apply and very effective. "SOD IS is really easy" said one of the women. " I just put the bottles out in the morning and forget about them. In the evening, wh en I finish my ocher work, I j use bring them in. We no longer get h eadaches [associated with typhoid] and diarrhoea. SODIS is cheap, and we can get the bo ttles ourselves."


INTERNATIONAL

REPORT

T w o o f the other schem es in this superstru ctures. T he VIP (ventilated p roj ect are m ore complex. One will improved pit latrines) to il ets provide pro vid e a pip ed wa ter fr om a a fly-free simple sa nitation sys tem. previo us w hite settler's weir via a 20 D rough t conditio ns prevailing in km gravity system to abo u t 200 Zam bia have sa pped th e abili ty of h ouse holds. T hree days each week, these very poor commun ities to abo u t 100 co mmu n ity m embers prov ide t he anti cipated supp ort labori ously dig tren ch es and lay origina lly en visaged, but in spite of pip e. This self- help group has bee n chis they are making substantial working for 10 years towards a water progress. Alec M wal e, the proj ect supply, and now their dream is with.in engineer, has done a mi ghty job in reach. managing the insta llati o n of 25 b ores and hand - pumps in ve ry Another group, also about 10 years remo te and d ifficu lt conditio ns, at a old, has sunk a 140 metre bo re , and tota l cost of AUD 225 000 . pumps wa te r into a 15 0,000L r eservo ir. From here, a gravity pipe Conclusion system w ilJ d istribute water co 200 In spite of the enormous di ffe rh o useholds. Although the wa ter is e nces in th e way th ese proj ects are b acteriolo gicalJy safe, it has dangerfun ctio nin g, th ey have a number o f o usly high co ncentratio ns of£lu o ride fea tu res in com mon: (5. 4mg/ L compared with W H O g ui d eline o f 1.5mg/ L). If used T hey are cost- effec tive. T he two proj ec ts in Kenya are providin g witho ut treatment, it wo uld ca use fl uo r os is, a ve r y debi l it a tin g m odest am ou nts o f water (40-50 L per perso n per day) at a cos t of condition. between AUD 30 and AUD 50 per Fortu nately, the local C ath olic perso n. T h e sc ho o l p roj ec t in D io cesa n W a t e r Pro g ra m h as Z ambia costs about AU D 40 pe r pioneered a simple system fo r fluoride pupi l (and th eir famili es benefi t coo) re mova l using bon e char. Bones are for water and sanitatio n in frash eated to a high temperature (400°C) tru cture. and crushed to produ ce an apatite residue , with a very high specifi c T hey place a great dea l o f Mary Kabura can give this water to her family, surface suitable fo r adsorbing fl uoride. confident that the household defluoridation unit e m p h asis o n e mpo we rin g th e commun ity members to ensure that The adso rption pro cess ca n b e has removed harmful levels of that chemical. reversed (regeneratio n) by raising pH . facil ities will be maintain ed , and th e Fo r ho usehold sized de-fluo ridatio n benefits are sustainable in the long units, the regeneration process is ru n. T h is i ncl ud es n o t onl y c arried o u t in th e factory site by a team helping com111un1t1es provide a water equipment, but also behavio ural issu es. supply (usually a hand-pumped bore) and fr o m the Fluoridation U n.it. • T hey ch oose tec hno lo gy in tervento ilets to 32 sc ho o ls affi liated with the T he advan tages of the bo n e char tio ns at an appropriate level, able to be R eform ed Open C onun unity Schools m ethods in a rural setting are that all the managed by the commun ity. gro up, run by the R eformed C hurch of • T hey actively seek to work with th e m aterials used are locally-available, and alJ Za mb ia. sp ares and chemi cals can be purchased in poorer sectors of the co mmunity in a non a lo cal ha rdware sto re (except the bones, T hese schools are loca ted in poo r d iscriminato ry manner. shan ty com pounds in u rban areas, and in which are ubiquitous!). T he day to day • All are stron gly com mun ity-dri ven. m ainte nance is minimal - no ch emical poor and remote villages in ru ral areas. T hey are ma naged by loca l non-govern addition o r cleanin g is needed . T he Fami lies stru ggle to pa y eve n ve ry mental orga nisations, in partnership with n1.eth o d h as hi g h flu oride-re m o val no minal co n tributio ns. C hildren are local co mmu nities, m eetin g stro ngly e ffi ciency, rega rdless o f th e influent freque ntly undernou rished , and their voiced dema nds and relying on lo cal concentrati on and vety low cost. T he cost ho m es h ave very poo r wa t er an d participatio n. p er household unit (20L) is AUD40. After sanitation provisio ns. Many com e from T his is water aid that w orks! 6 months, regeneration is usually required . fa m ilies where one o r both parents have died of AID s. G randparents often have to Th.is costs AUD1 0. T ypical run ning cost The Author is 7 cents p er 20L o f treated water. take res po nsibil ity for chi ld ren left Darryl Jackson is a senior project o rp haned , often without any sou rce of Water and Toilets for Community engineer in Earth T ech Engineering's income . T he sc hools have rudimentaty Schools W ater Industry G ro up , and a fo rm er fac ilities, vety few had any access to water, EAR Australia fieldworker in India and T and most had only one or t\¥ 0 pit latrines, In Z ambia, com munity schools are N e p al. T h is w as Darryl 's seco n d prone to collapse during wet weath er. providing an affordabl e edu cation o ptio n visit to these three projects, monitoring for very poo r fa milies w ho do no t have The proj ect has been supplying fu nds as part of TEAR Australia's agreem ent th e money for fees, unifo rms and books for capital items, but community members w ith AusAID. email: djackso n@ fisherr e q ui r e d by c h i l dr e n a tt e nding provide the labo ur, m aking bricks by stewart. com.au go vernment schools. This proj ect is hand , digging pies and bu ilding the

40

WATER MARCH 2003


INTERNATIONAL

REPORT

Nakuru. Patience and commitment In the neighbouring district ofNakuru, getting water consumes even more of women's time and energy. Some women reported that they sometimes get up at 3 :00am, so they ca n get to the waterhole before it is muddied by an imals and other people. Most of the people are small-scale farmers who rely on subsistence mixed farming. The majority are settled on forme r colonial farms which have been subd ivided to an average of 1.5 hectares per household. The area is sem.i-arid, with an average rainfall of 600mm. Many of the households are headed by women. 1e's not surprising therefore that the Nakuru Diocese C hristian Community Services (the implementing agency) has linked with existing women's co-operatives in order to help bring water to thirsty villages. Some of these groups formed up to nine years ago , committing themselves to save and work together until each member had a concrete rainwater tank to provide for household needs . While the project has trained 40 tradesmen to supervise the work (a valuable input in

A member of the Toret Gaa Women 's Group shares a glass of water with the author, Darryl Jackson.

itself!), the women do all the unskilled work themselves, from digging foundations and chipping and dressing stone by hand, to mixing and placi ng concrete.

Because of the project's assistance, the groups will be able to meet their goal much faster than they wou ld have by relying o n their own meagre resources.

Things not flovving srnoothly?


B

PIPELINE

FEATURE

CRITICAL WATER MAINS THE NEED FOR RISK ANALYSIS R Radovanovic, A Marlin Abstract Sydney Water has various strategies in p lace fo r pro-ac tive man age m ent of its assets and in particular those critical assets w hose fa ilure has signi fica n t effects on wa t e r su pp ly an d/or co mmunit y disruptio n th ro ugh fl ooding and consequential damage . T hese strategies have now b ee n c o nsol idated in to asset n1.anage ment plans (called Asset C lass Pl ans) fo r the va ri ous majo r classes of assets. T he plans describ e th e current approach and improve ment projec ts for th e plannin g, creati o n, main tenan ce, re n ewal and disposa l of assets. T he pl ans include a th irty year capital and o peratin g investment program fo r each class of assets to cater for growth in the custo mer base, asset main tenance and improvement to service standards and renewa ls. Th e water mains asset man agem ent plan fo rms part of Sydney W ater's asset n1.anagem ent framework and is on e of the s ui te of asset plans cove ring water, wastewater and stormwater assets. T he key element of the water main plan is life cycle m anage m ent th at in vo lves a ri sk n1. anage m e nt a p pr oac h t o a sse t m anage men t. This paper o utli nes the principl es b e hind chis risk- based approach co water 1nain asset managem ent in Sydney W ater.

Background For o ver 10 years Sydney W ater o p erations were m anaged as four R egional ar eas. Unfortunately, over time, chis produ ced a ten dency fo r each area to work to som ewhat different in asset m a na ge m e nt s tr a t eg i es . Sys t e m Management Plans were developed in the mid- nineties to fo cus on the critical issues in managing systems and their assets. They proved extremely useful in fo cussing on i ss u es from a sys t e m op e r a t i o n s p e rspective, but, in asset managem ent, with over 30 plans fo r water system s alone, it was difficult to coordinate an d en sure a c onsistency of strategy an d approach .

This is an edited version of a paper presented at the CSIRO Seminar on Asset Management of Pipelines, November 2002 .

42

WATER MARCH 2003

Wu tc r Plun 2 1

A REA PLANS Sydney Harbo ur N 1h Beaches

I

Sou1hcm Sydney

Hawkcsbur y-Nepcan

I

lllawarra

I

ASSET C LASS Pl. ANS W ATER

W AST EW AT ER

STORMWATER

Water Mains

Sewers

Pumps

Pumps

Pipes. C hannels and Flood ways

Reservoirs

S1orngcs

Facil ities

Facil i1ies

T reaunen1 and S1orn gcs

Control s and M oni toring

Diagram 1. Hierarchy of Asset Class Plans and Area Plans.

Present Situation M o re recently, Sydney W ater was restructured into a mo re centrally based organisational structure w ith all technical areas in planning, operatio ns, and maintenan ce und e r o n e umbre ll a asse t managem ent business. Under these new arrangem ents it is no w easier to fo cus on the asse t management strategies needed fo r the various major asset classes across the whole o rganisation. A Strategic Framework fo r Asse t Man age m ent w as d eve loped , fo llow ed by the production of Asset Class Plans and at present Area Plans are being

prep ared. The Asset Class Plans are documents dedicated specifically to water, wastewater and stormwater assets and fo cus on the life cycle management of those assets within a thirty year horizon. The Area Plans outline Sydney W ater's service delivery strategy for each of four areas, interpreting the relevant Corporate Plannin g document called W aterPlan 21. The Area Plan integrates planning for Sydney W ater 's water, wastew ater and stormwater services w ithin the area. The impacts of growth , oppo rtunities fo r innovati o n in se rvi ce delivery and

W1ttr M1 ln 1 by C 1 l1g o ry I Plp t Type

Figure 1 . Water Mains by Age, Length and Material.


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PIPELINE

s u stain a b le m a n age m e n t o f w at e r , w as tewate r and sto rm wa te r w il l b e ide ntifi ed. le is intended that these plans w ill help in the furt her develo pment of an integrated wa ter cycl e manageme nt ap proach to th e provisio n of services. D iagram 1 outli nes th e hie rarc hy of th e asse t plans and area plans fo r ea ch produ ct. D iagram 2 o utlin es th e framework for the preparatio n o f th e Asset Class Pl ans.

Overview of Water Mains Asset Stock T he Sydney water main ne tw ork consists of approximately 20,000 km of pipe lin es, ranging in size fro m 100 111111 to ove r 3 111 in diamete r. T he do minant mate ri al used in chis pipeline network is "grey" cast iron (72%), whilst ductile iron re prese nts 20% o f th e system , stee l 4%, poly vinyl chlo ride (PV C) 4% w ith glass reinforced plastic (GR.P), asbestos ceme nt (A C) and copper making up the rema inder (see Fi gure 1). Th e installation of "grey" cast iron pi pes ceased in th e earl y 1980s, and togethe r with AC pipes, are no longer installed fo r wa ter delivery purposes. Approx imately 17 ,900 km s (88%) re present reticulation mains below DN375 and 2,300 kms ( 12%) represent tru n k 111.ains DN375 and abo ve .

Management of Water Mains W ater U tiliti es w ill agree that the re are two certainties about the li fe cycle of any water main that is, that so me day the water ma in w ill fail and the re w ill be consequences fron1 the failure . Th e uncertain ty is that w e do not know specifically when and where the water main w ill fail or the severity and scope of

Due Diligence Strategy (Asset Condition Monitoring)

FEATURE

Context

Introduction Overview of Existing Assets Performance Requirements

Demand

Life Cycle Management

Capability

Current Performance

Analysis of Gaps

Options

Options Assessment

~

Investment Plan

Action Plan

Performance Monitoring and Review

Diagram 2. Structu re of asset class pl an document .

the co nseq ue n ces arising fro m that fai lure . The main reasons fo r th is un certainty is that wa ter mains are diffi c ult to assess for conditi o n, because: • The materials themselves arc structu rall y diffi cul t to assess, • 95% o f watermains are buried and many have limited access situated unde r roads e tc.

Intensive Strategy (Risk assessment, control & asset renewal)

~ High

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Critical water mains (eg Larger old Cast iron in aggresive soils)

• M ose crun kmains have limited operation a l fl ex ibility to alJow le ngt h y shutdow ns for condition assessme nt. R.i sk M anagem ent deals directl y wit h fac tors of probability and con seque nce and , the refore, is an appropriate tool to use for these type o f assets Th e standard risk analysis equatio n has been applied in th e strategy, name ly: Risk = Proba b ili ty x Consequ en ce Figure 2 provides a graph ical estimatio n o f how Sydn ey's netw ork might be presented in a risk matrix and th e type o f mana ge me nt strategies th at are put into place to manage th e level o f risk .

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Th e fo cus for this paper wi ll be those water mains that have a high criticality that is, high co nsequence of fa il ure .

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H avin g decided to ado pt a risk- based approach to man age critical water mains the key questio ns to b e answ e red are : • What funding allocatio ns are requi red now and into th e futur e to minimise the risks of fail u re of criti cal w ater main s • How to identify th e w atermains that need to be re n ew ed/ re habilitated • H ow to prioritise those candidate wa termain s to be re n ewed/ rehabilitated

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44

WAT ER MARCH 2003


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PIPELINE

These three qu estio ns are dealt w ith in Sydney W a ter's Wa te rm a in Ri sk M a n agem ent Strategy and W ater M ain Asset C lass Plan .

FEATURE

RISK IDENTIFICATION (DESK TOP SCREENING )

WA TE R MAIN CA TE G OR ISA TIO N

Water Main Risk Management Strategy This Strategy is a structured m e th odology to m anage w ate r m ains using a ri sk - b ased a pproa c h t h a t c an b e summa rised in a th ree step process as fo llows (refe r also to Fi g ure 3) :

1. Budget forecast for water main rehabilitation/ replacement Th e America n W ate r & Wastewater A ssoc ia ti o n R ese ar c h F o u nd a ti o n (A WW ARF) developed a survival model to h elp calculate t he p ipe re habi li tati o n a nd re pl acem ent needs for wa ter d ist rib u t io n net w o rks. T h e key supp o re software package called l<ANEW is a statistical based analys is that uses th e hist ori cal in ventory o f wa termains and p ip e m aterial and use r in puts o f the estim ated survival profile of each pipe type to p redict the length of pipe to be re habilitate d o r replaced on an annual basis. It is a m acro model useful for finan cial pla nning fo recasts.

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Manaao Hlah Conseauence of Failure Field verity pipe, valve & fllllno locat,on

# Prepare strip maps RETICULATION MAINS ( 17 ,900 kms )

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Figure 3. Risk Management Strategy For Wat er Mains.

Sy dn ey W a te r h as ut il i se d t h e KAN E W m ode.I t o d e te rmin e th e perce ntage of to tal pipe le ng th fo r water m ain rehabil itatio n and renewal as a glo baJ lo ng term planni ng tool. T his process was applied to both trunk m ains (~DN375)

and reticulatio n m ains (<D N 3 75). T he leve l of ex pend itu re determ in ed thro ug h th is process is, o f course, subject to the usual budge t constraints that may ex ist in an y partic ul ar year. Th e I<ANE W m odel does no t ide ntify specifi c pipes to be

WATER MARCH 2003

45


PIPELINE

replaced and, therefore, separate processes are used to do this for critical and noncritical water mains. 2. Identification of water mains needing rehabilitation/ replacement T his step has a different approach for trunk mains and reticulation mains, as follows : Reticulation Water Mains (<DN375) - Non- Critical Based on acceptable risk, the bulk of the non-critical reticulation water mains will be run to failure. Failures are monitored until a threshold is reached where the water main is considered for investigation and financially evaluated for renewal. Every main break or leak repair is logged into a database including information relating to street location, property number, size, material, cause of failure and cost of repair. The database is interrogated to identify repeat breaks w ithin the same street. The trigger, currently sec at 3 or more breaks in one year or 5 or more breaks in two years, is the criteria used to initiate detailed water main investigations. This detailed investigation involves review of pipe failures, consequence of failure, cost of repair and a financial evaluation of renewal/rehabilitation options. Trunk mains W ater Mains (2:DN375) and Reticulation Mains (<DN375) Critical Initially a desktop risk study is necessary, as it is not practical to undertake condition assessment on all pipes within a short period. It, therefore, is strategically important to prioritise the critical main stock to target pipes according to their risk level. Desktop criticality analysis C riticality is determined by a desktop analysis of severity of the consequences of a failure. If the consequences are readily manageable then a run to failu re approach is considered acceptable. A coarse consequence analysis of every trunkmain and selected reticulation mains is firstly necessary to assess the level of criticality that, when combined with failure likelihood, can be used to prioritise water mains for further condition assessment. T he factors considered in this analysis are shown in Table 1. One outcome of this analysis is a prioritised list of water mains by criticality score. Based on this ranking, water mains are then selected for development of shutdown manuals and contingency plans. The aim being to manage the failures that do occur as quickly as possible, by:

46

WATER MARCH 2003

FEATURE

Table 1. Impacts of Failure. Customer Impacts

Community Impacts

• Loss of supply

• Flooding and erosion

• Cost of water losses

• Reduction in water pressure

• Health and safety

• Cost of customer rebates

• Road and property damage

• Cost of response to restore supply

• Environmental damage

• Cost of repair

• Traffic disruption and

• Cost of road restoration

• Publ ic image and perception

• Cost of thi rd party damages

• Deterioration in water quality

Financial Impacts

• Cost of environmental restoration

• Knowing which valves to operate in an emergency • Knowing where the valves are located, and • Being confident that the valve will be fully operational Desktop failure likelihood Desktop coarse ana lys is of the likelihood of failure cakes into consideration the following factors : • Age of pipe • Material of manufacture • Internal lining • External coating • Jointing method • Soil environment Desktop risk score Having completed the desktop failure consequence and likelihood analysis the combined risk score is used to rank critical wate r ma ins fo r ongoing detailed condition based probability assessment and quantitative consequence assessment. Condition Assessment - Predictive evaluation of failure probability Based on recent investigation and pilot research into non-d estructive, noninvasive condition assessment techniques, the following techniques will be adopted for predictive assessment of failure probability: • Geonics • Soil sampling • Linear Polarisation Resistivity testing and Extreme Value Statistics • External 'Mainscan' measurement on cast iron pipe • External 'Ultrasonic' measurement on steel pipe • Coupon sampling As technology develops it is anticipated that an internal 'pig' device will be used to undertake more accurate pipe condition assessment and probability prediction. This process will identify sections of water main with various levels of probability. Each section will then undergo a

detailed quantitative field based consequence analysis. 3. Prioritisation of water mains for rehabilitation/ renewal The combination of probability and consequence w ill provide a risk score for each section of water main, that will enable prioritisation for investigation into most suitable and appropriate control actions.

Future Programs Sydney Water aims to complete the pilot project and assessment of condition assessment techniques in J une 2003. When completed, the Watermain Risk Management Strategy can be finalised. The above work is part of Sydney Wa t er's Critical Water Mains Rehabilitation Progran1 that involves desktop criticality analysis, condition assessment of pipes, valves and fittings, quantitative consequence assessment and risk ranking. The program instigates additional maintenance on fittings (where required) and will identify and prioritise water mains for renewal. The program will also include the ongoing development, review and trials of shutdown manuals for all designated critical watermains.

The Author Rudi Radovanovic is 'Planning Leader, Water Assets Management' and Alan Marlin is 'Project Manager, Water Operations', with the Sydney Water Corporation. Email rudi.radovanovic@ sydneywater.com.au

References 1. Framework for Strategic Asset Management - Sydney Water, 2001 2. Water Plan 21 - Sydney Water, 2002 3. Water Mains Asset Management Plan - Sydney Water, August 2002 4. T echniques for the condition assessment of buried iron and steel pipelines - Sydney Water 2001 5. Report on identification of critical water supply assets - UWRAA Research Project AM- 14 1993.


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Ill

PIPELINE

FEATURE

SOILS INFORMATION BY GIS FOR IN-GROUND ASSET ANALYSIS I Allan, R van de Graaff Abstract 3路7路 35

In the w ater industry, in-ground asset performance is assessed according to facto rs such as failu re freque ncy, asset condition and material life expectancy. It is known that soil mechanical, chemical, acidity and moisture properties impact on asset life exp ectancy, but such information is not generally factored into asset li fe estimates because it is rarely available. In this sense, urban areas tend to be asset rich but information poor. In this pap er we show that soils inform ation often exists as archives that can be restored. However, to be most usefu l, this information requires 1nanipulation by software to ensure a consistent spatial database. Soil scien ce expertise can be encapsulated in the software and database, and any number of us e r -defi ned n-iap s (ie shrink/swell, pH, etc . at use r defined depths) can be produced . Using the spatial query functionali ty in a GIS , attributes of individual assets can be applied at the point in the soil profile in which they lie.

Introduction Society has a great need for protecting and managing existing infra-structure such as roads, pipelines, sewer and storm water drainage systems, and for making best use of any terrain knowledge upon which n ew infra-stru c tur e will be bui lt. Geological and topographic maps are already widely used, often in combination with aerial photographs and other remotesensed data. However, soil maps are often overlooked and the geological m aps may be inadequately utilized. Soil maps often portray the distribution of soil types in terms which are not easily understood by the engineer, as most of these maps are produced not by geotechni cal or civil engineers, but by agricultural scientists using thei r own terminology. Geological m aps too are made by geologists for their

O

48

WATER MARCH 2003

soil

r:::::;Jgroni te

Figure 1. A block diagram of a Terrain Pattern on Melbourne's Mornington Peninsula (Grant 1973). Note the application of the catena concept. The 34.00144/2 terrain pattern has three soil descriptions that re late to hill crests , slopes and drainage lines.

own purposes and usually ignore the geomorphological processes - erosion, deposition, weathering and hence the soil mantle - that have affected the landscape and the soils formed from th e geological parent materials. When all these databases are combined and produced in an acc urate spatial database, new and valuable inferences ca n be made with regard to society's infrastructure asse ts that are located in or on the soil. Moreover, the boundaries of the mapping units can become more reliable as these are related to topography for which much more precise information is now available. Using the CS IRO's numerical system for identifiers of properties of geological and soil properties and fo r landforms (Grant, 1975(a), 1975(6)) , we describ e a m ethod of mapping and value adding of the terrain patterns around M.elbourne that has great potential for society.

Understanding Soil Surveys This is an edited version of a paper presented at t he CSIRO Seminar on Asset Management of Pipelines, N ovember 2002.

9 路 2路80

Traditional soil mapping is slow going beca use it involves much fieldwork, soil augering and hand texturing. In the

1960s-1970s techniques known as Terrain Pa ttern Mapping evolved (Aitchison and Grant, 196 7) and Land Systems M apping (Christian and Stewart, 1968) that allowed large areas of terrain to be mapped very quickly at low cartographi c detail but relatively high descriptive content. The former took an engineering fo cus, whilst th e latter had an ecological, multidisciplinary approach as it aimed at sound land deve lopment and management in rural and undeveloped regions. At the time Australians were amongst the world leaders in its use . T he land systems techniqu e applied a soil scientist's knowledge of soil pro cesses to existing geological m aps and known geomorphological hist0 ry to produ ce models of soils in th e landscape. For exa mpl e, the concept of catena allowed a soil scientist to predict with a degree of certainty that soils at the top of hills would be less moist, better drained (more oxidized) and have bedrock at shallower depth, compared with soils at th e base of hills that would tend to be deeper, more moist and subj ect to frequent periods of anaerobic redu cing conditions, heavier in


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PIPELINE

texture, with bedrock at greater depth (Figure 1). Similarly, older, more highly weathered soils show chemical, mineralogical and morphological features that younger soils do not have. These weathering processes - soil formation - have been thoroughly studied by soil scientists fo r m ost oflast century. For example , the old plateau remnants along W hiteho rse R oad in Nunawading, Victoria, have mu ch deeper so ils than the young dissection slopes towards the Yarra and its trib utaries in T e mpl es to we. Th ese processes even influ ence the movement and inm1obilization of heavy metals in the environment and are useful in assessing contaminated sites. W e have found that using GIS in combination with soil science knowledge allows fo r much value adding to be undertaken. Other relationships such as soil pH and salinity can also be explored . W here parent geological formatio ns are constant over wide areas, associations can be made betwee n soil types and rainfall. In high rainfall areas soils become leached and develop low pH and negligible salinity and the pH will tend to be lower with increasing soil age ; however, a pH of 4.5 is usually the minimum va lue found. An example of this is th e soils in the H eidelberg/ Rosa nna area (mean annual rainfall 860111111) and those in the Wandin area (mean annual rainfall 1000111111). Ocher areas might be affected by acid sulfate soils, in w hich case the p H can be much lower. Such areas are generally old swamps, the soils from w hich contai n sulfides, w hich combine with air w hen disturbed to form dilute su lfuric acid. This knowl e dge ha s implications fo r co nstruction managem ent b ecause the longer these soils are exposed to air, th e more ac idic they become. In M elbourne, areas of the old Carrum Carrum Swamp come to min d, but the Coode Island Silts have become more notorious. Soil surveys tend to exist as paper archives that can be restored and made digital. In the next sec tion we desc rib e som e issues that should be considered before res toration begins. Digital maps versus spatial databases Many people think chat a digitized pap er map in a GIS is a spatial database, but this is rarely the case. The conceptual difference betwee n a digital map and a spatial database can be difficult to grasp. A paper map that has been digitized is most often just a digital m ap. Digital soil maps are very useful in a GIS because they can be visually related to in-ground ¡assets,

50

WATER MARCH 2003

FEATURE

GRANT (1972)

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Map 1. The key map from the SEWL scoping study. There were 14 separat e datasets in the stu dy area, most of which were of different scales and descriptive syst ems. These were interpreted to be a single standard.

but they are rarely organized in a manner that makes it easy for any comparisons other than visual ones co be reliably undertaken. Conversely, a spatial database is one that is especially designed to allow valid queries to be made across a map. A digital map is often the starting point for a spatial database, but it must be developed further. T wo important aspects of a spatial database relate to spatial integrity and attribute consistency. Spatial integrity Spatial integrity relates to the accuracy of the boundaries used to create a digital map. The accuracy should be appropriate for the use to which the bou ndaries are to be put. For example, it may be inappropriate to relate a ve1y generalized soil map to a very accurate cadastral map. If many different soil maps from many different sources are to be joined, then the resulting map is unlikely to be valid if the mapping scales and boundary acc uracies of the constitu ent maps differ. Attribute consistency Adjoining soil maps are often produced in ways chat describe identical soils differently, because over time different authors used different soil classification systems and mapped at different scales, so that m ap ping units are ge n eralized variou sly. These need co be reinterpreted to a single standard. Even those m aps that have been configured in such a way are rarely (never?) configured to be searchable within a relational database. Most often, in our work, soil attributes are provided as text desc riptions (e .g. in an Excel spreadsheet) that are attached to the mapped data in the GIS. This means

chat a description ca n b e displayed with the mouse cursor. This func tionality is us eful to h elp explain problems in individual areas. Ho wever, the interpretation of the description requires much skill, is labour intensive, and difficulc to apply to a whole study area in a computer m odelli ng sense. The importance of software A software component is required to exploit a spatial database. This ensures that all mappin g that a use r und ertakes can be repeated. Because software is not forgiving of poorly fo rmatted data, it also ensures rigor in the way that data are represented. Software can also help overcome mapping issues where , as is often the case, a soil polygon is described in greater detail than it can be mapped . What sort of information can be produced D escriptive soil information (suc h as clay content, gravel, prese n ce of 'buckshot', colou rs and mottling, soil stru cture and consistency, field pH, penetration by plant roots , biological channels, etc.), provides important clues that a soil scientist can use to derive those soil "attributes" that are relevant to the water industry's qu est to explain asset failure , model asset fa ilure risk, and schedule and budget asset maintenance . For example, soil texture refers to the proportion of sand, silt and clay particles in the soil and therefore plays a role in soil structure forma tion which refers to the system and stability of inter-particle, inter-aggregate and biological voids, which in turn affects permeability and natural drainage. Soil texture is also of


PIPELINE

great importance in governing waterholding capacity. Depending on the mineralogy of the clay as well as the percentage of clay in the soil, the soil will be more or less subj ect to volume change stresses, wh ich are related to stresses experienced by pipes and footings. Soil colo ur is an important, rough , indicator of the state of aeration of the soil. Whole colou red so ils, especially if th e colours are reds and browns, are indicative of soil water regim es dominated by oxidising conditions, i.e. very good drainage. Grey and yell ow mottles, or uniform grey and bluish colours indicate respecti vely periods of reducing conditions, he nce period ic waterloggi ng, o r constant saturation . Rusty m ottling along root channels in the topsoil i ndicates frequ e nt and long-lasting waterlogging. Few plant species can extend their roots into permanently saturated soil. Therefore the occurrence of root channels and hving or dead roots at depth indicate that at least for mu ch of th e time there is a supply o f Oll.')'gen th ere. Buckshot concentrations in the subsurface soil on top of a clay subsoil indicates the occ urrence of frequent perched water tables on the subsoil. From the m ineral transformations in these pro cesses, ma inly ex hi bi ted by the u biq uitous ir on and m a n ga n ese compounds, one can deduce the chemical boundary conditions of p H and redox poten tial that govern in the soil. Fol lowing are some exampl es of soil attrib utes that we believe are especially relevant to the water industry . • M e chanical attributes: Shrink/swell maps should indi cate areas w here the differing wetness regimes of driveways and natu re strips will lead to mechanical pressure on assets. Also relevant is the interface between very heavy and ve ry light soils. • Profile w ater-holding capacity : Soils with high water-holding capacity remai n m o ist much longer, potentially increasing the time of exposure of the asset to corrosive agents in the soi l moisture, as well as potentially affec ting the ease of excavation, but will dampen the intensity of so il volume c hange. • Soil wetness: This attribute has a bearing on the length and frequ ency of periods d uring which low redox potentials exist. If combined with sa linity it affects the degree of dilutio n of salts in the aq ueo us phase in contact with the asset. It also affects the depth to w hich root, will penetrate, as most terrestrial plants require oxygen arou nd their roots . 52

WATER MARCH 2003

FEATURE

Dominant soils Clayso,is(G)

<:Jay so,ls (U or G) Clay so,ls underneath sand (G) ~(; Rock ou1crop, pockets shallow soil and gravel . Sandy sols (U or G) Strallfiod soils

Map 2 Composite soil p,olole

Indicative soil texture at 0.5 Metres Clay Heavy Clay Sandy Clay Silly

Map 3: Soil texture at depth

Indicative shrink/swell at 0.5 Metres Very slight Moderate Hogh

Map 4· Ono soil attnbutc {shnnklswell) at deplh

Maps 2,3 and 4 .

• Biology: Input from pl ant b iologists with regard to the soil environment is likely to lead to greater predictive power about where the roots of ce rtain tree species are mo re li kely to invade drains. • Corrosivity: Acid-su lfa te soi ls are especially destructive on steel and concrete pipes, and, if brought to th e surface in excavations may produce h igh ly acid leachate, w hi ch could kill vegetation and mobili ze heavy m etals already in the soil.

• Resistivity: T his is esp ecially relevan t in predicting the deterioration of case iron pipes. T he opposite of resistivity 1s electrical conductivity, a test that 1s ro utin ely carried out on soil sa mples 111 the laboratory fo r testing soil salinity. • pH: Some ge nera l interpretations can be made usin g geological descripti ons, terrain pattern descriptions and rainfall records. pH is important because increased Co111i1111ed 011 pase 56


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PIPELINE

Co11ti1111ed.fro111 page 52 ac idity also increases the corrosivity of the soil. If the soil's buffering capacity is taken into account, the p H can be a measure of the difficulty of amending the soil with lin1e. â&#x20AC;˘ Redox potential: The variation o f so il p H and redox potential in natural soils has been delineated by several research es in order to pred ict th e possible reactions that may take place that can affect speciation (ie the exact com.pound in which an elem ent such as iro n o ccurs) . and solubility of m etals in the soil. It also may be p redictive of corrosivicy . Archival mapping is the biggest obstacle One of the biggest obstacles co gaining soils info rmation is that a single soil archi ve rarely covers an authority's area , and wh ere multiple archives exist, they are rarely co mpatibl e. When restoring so il archives, the bigger the area, the more difficult the task becomes. The example in Map 1 relates to so il ma pping w e undertook for South Ease Water Limited. T here were fourteen different studies, of different scales, with different spacial extents, using different m ethodologies, and with diffe re nt descriptive detail. In the study, we applied the very detailed attributes from a small-scale CSIR O series o f terrain pattern studi es to mu ch larger scale (a nd poorly described) geological boundaries. The result was a 1:250,000 scale terrain pattern map reinterpreted to be 1 :63,360. We are currently undertaking a similar sized proje ct for Yarra Vall ey Water. In the Melbourne metropolitan area it is not un common to fin d bounda ries o n geolo gical map s that range from being perfec tly positioned, to being as much as 200m displaced. In rural N SW last year, we discovered a soil boundaiy that was misaligned by m ore than two kilometres . Reasons for such map error relate to scale of interpretation , a ca rtographic requirement to accentuate areas of geological im.portan ce, and th e technology used to produ ce the maps. These discoveries have allowed us to improve our m ethodology. In th e current study, we are using a variety of datasets to improve accuracy and are presently interpreting this data at a scale of 1 :25,000. C learly, if you know w hat you ' re lookin g for, many archival maps can be sa lvaged, and in deed, value added . T he

56

WATER MARCH 2003

FEATURE

biggest challenge is knowing what is important and w hat is not. In the following sectio n, we' ll lo ok at the benefit that can be ga ined when a spatial d ata base is combined with software .

Bringing It All Togethe r Using Gis There is m uch valu e that can be added to soil maps with a " threepronged" approach chat involves the use of a spatial database, attribute database and G IS software. Map 2 shows the sort of mapping tha t was undertaken in the 1970s when G IS functiona lity was bu t a drea m. In those days, the productio n of eac h additional theme required enormous consid eration du e to the implications for additional tim e and expense. H ence maps suc h as this one showing dominant soils only. More significantly, Map 2 is a composite map of an entire soil profil e based o n the understanding of an experienced soil scientist . Map 3 shows the same area as in Map 2, chis time mapped for so il texture at a depth of 0.5 metres using the "threepronged" approach. The soil descriptions are simplified in this m ap, and th e six classes in M ap 2 have become three. Because the software was instru cted to ignore rocks, areas of rock outcrop have been redefin ed to be heavy clay. Finally, Map 4 is in a form that is probably of the greatest use to decision ma kers . The legend documents the map in nominal/ relative terms. It is interesting to note that the three types of clay shown in M a p 3, eac h h ave d iffe r e nt shrink/swell characteristics. Because the so il scientist's expertise has been encapsulated in the software and database, any number of user-defin ed maps (ie shrink/swell, pH, etc. at user defined depths) can be produced, and using the spacial query fun ctionality in a GIS, be applied as attributes of individual asse ts at the point in the so il profile in whi ch they li e.

Conclusion T he information that is available in geological maps, so il maps and terrain maps of varying dates and scales can be 'mined' , updated and presented in an accurate spatial data base for a range of practical interpretatio ns. A GIS approach can then be used to attach these interpretations as attributes of individual assets for use in asset risk an alysis. Th e systematic m etho d of using identifiers developed by Keith Grant of CSIR O

allo ws subsequ ent subdi vision of spacial and categorical in formatio n as new information is obtained . To do this requires a re- interpretation of the older data bases, in which geomorphology and soil sc ien ce are part ic ularly usefu l elem ents.

Acknowledgements The authors acknowl edge the contributio n of Dr Mike Sm ith, of CTL Pry Ltd.

The Authors Ian Allan is M anaging D irector of Geocode Maping and Analysis Pry Ltd . Dr Robert van de Graaff is Principal of van de G raaf and Associates Pty Ltd .

Geocode (integration, manage men t and G [S modelling of environmental in fo rmation), va n de G raa ff and Associates (waste water re-use and land capa bility assess m e nt s) and CT L (e ngineering and proj ect management) collaborate co pro vide G IS m odelling services to assist the water industry with stra tegic decis ion making. Typical projects involve the integration of soils, terrain and other environmental informatio n. Examples of applications include in-ground asset life expectancy analysis, Land and Water Managemen t Planning, and the assessm ent of rural subdivision suitab ility. The group ca n b e contacted t hr o u g h Mik e Sm i t h, P r in c ipa l C onsultant, CTL Pty Led, PO Box 115 Balwyn North, VIC, 3104, Phone: 041 8384 7 17 , email: CTL@ bigpond.net.au,

References l. Aitchison G D and Grant K (1967) The PUCE Programme of terrain description, evaluation and interpretation for engineeiing purposes. Proc. 4th R eg. Conf Africa Soil M ech . Fdn . Engng. Vol. 1, Pp.l-8. 2. C hristian C S and Stewart G A (1968) Methodology o f integrated surveys. In: Aerial Su/'lleys a11d Integrated St11dies. Proc. Toulouse Conf. 1964, UNESCO. Pp.233280 . 3. Grant K (1975a) The PUCE Programme for terrain evaluation for engineering purposes. I Prin cipl es . CS IR O A ust. Div. Appl. Geomechanics Tech. Paper 15, 2nd Editio n. 4. Grant K (19756) T he PUCE Programme fo r terrain evaluation for engineering purposes II. Procedures for terrain classification. CSIRO Aust. Div. Appl. Geomechanics Tech. Paper 15, 2nd Edition. 5. Grant K (1973). - Terrain C lassification for Engineering Purposes of the Queenscliff Area, Victoria, Di vision of Applied Geomechanics Technical Paper No. I 2, CSIR.O, Melbourne .


PIPELINE FEATURE

D

ASSESSMENT OF FERROUS PIPELINES: A NEW DEVELOPMENT M Roubal Abstract New developments in non-destru ctive testing technology are yielding excellent results in the condition assessment and ]jfespa n estimation of ferrous water mains, sewers and gas su pply pipes. The recen tl y d eveloped " M ain s Assessment Probe" (MAP) tech n iques enabl e cost-effecti ve pipeli ne condition assessme nt to assist asset manage rs w ith allocation of maintenance and repair budgets, all owing uninterrupted service fron-i vital infrastru ctu re. MAP is an Australian product, designed and patented by Rock Solid Research in Melbourne, Australia. Th e US co mpan y American Investigation and Assessment Inc of Washi ngton DC (gradal@gwest. net) is a broad based investigation and assessment gro up who use the Ro ck Solid technology, along with others, to provide utilities worldwide with comprehensive eva luations of the condition of water, sewer and gas networks The ferrous pipe MAP is particularly usefu l for co nd ition assessment of water mains. It utilises broadband elec trornagnetics (BEM) technology to record data over a broad range of freq uencies. A significant adva ntage of this probe is the abi lity to survey tl,ro11gh ferrous pipe coa tings or linings. A recent case history from Redcl iffe, Queensland, provides impressive evidence of th e opportuniti es affo rded by this leading- edge technology. Alternatively, non-ferrous pipe MAP provides pipe embedmenc analysis essential for its structural integrity. By emitting low electromagnetic radiation through the pipe wa ll into the surrounding so ils the technique is capable of detecting structures such as voids, deconsolidated ground and other sub-surface mi cro-geo logical featu r es.

Introduction Most authorities undertake some level of asset maintenance and risk analysis. This is often based on 'desk-top ' studies

Figure 1 . a) Schematic diagram of the primary fie ld destruction originating from an axial sensor configuration.

involvi ng records of pipe perform ance history, pipe condition at the burst sites, and other anecdotal evidence. While these approaches may be relatively inexpensive, they can also be short-sighted, inaccurate, and fail to identify potential problem areas. When portions of a pipeline collapse, or bu rst, often the enti re pipel ine will be replaced. H owever, the cond ition of various sections of the same pipeline may be entirely different. Money and resources are often wasted when the decision to replace a complete pip eline is based onl y on desk-top swdies or limited testi ng.

An effective condition assessm ent program incorporating non-destructive testing techniques, such as BEM , involves surveying the pipeline infrastructure and/or surrounds co identify likely troubl e spots. Resul ts and recommendations then allow the authority or pipeline owner to target maintenance fun ds to specific areas of need. Wh ile replacement of an entire pipeline may cost millions of do!Jars, repair of the sections identified as problematic may requ ire only a portion of that amoun t. Appropriate condjtion assessment a!Jows utility managers and pipeline owners to target a Jim.iced b udget at the right spot.

E ddy current distribution

Figure 1 . b) Plan view of an induced eddy current from a fl at plate with no defects. c) the introduction of a fracture into the plate disrupts the regular eddy current pattern displayed in Figure 1b. WATER MARCH 2003

57


PIPELINE

FEATURE

Improved Assessment Techniques Until recen tly pipeline conditio n assessment primarily in volved the use of two techniques: ultrasonics, and magneti c fl ux leakage (MFL). Ultraso11ics co11ditio11 assess111e11t requires direct contact with the metal pipe wall for transm ission of a signal into the pipe material w h ich then provides data in relation to the nature of the material under examination. As ferrous pipelines are often ' lined' or 'coated ' fo r protection against corrosion , abrasion or water conta1n inati o n, costly removal and replacemen t of this material is required in order to undertake con dition assessment tests . Mag11eticjl11x leakage (MFL) involves the use of strong rare-ea rth perma nent magnets to assess the material und er examination. The magnetic force field, or flux, is 'channeled' by materials with high magnetic permeability suc h as ferrous alloys . Flux density near the su rface is a function of the material cross-section under investigati on as well as its magnetic properties. This technique is li1n ited co use in fe rrous pipes with a coating or lin ing thi ckness of less than 6111111. Greater displaceme nt of the sensor fro m the fe rrous surfa ce yie lds am biguous results. There are now two more recent developments:

The Broadband Electro111ag11etic (BEM) Probe records data at va rio us freq uencies which provides a significant advantage over m ore primi ti ve edd y curren t techniq ues that rely on the acquisition of a single or limited number of freque ncies. The methodology is rela ted to equipment currently utilised in th e mine ral explo ration industry fo r the sea rc h of massive

Figure 2. Multiple antenna BEM PIG (Pipe Inspecti on Gauge).

ore bod ies. The distinct advantage provided by this techniqu e is the ability to survey t/1ro11g/1 fe rrous pi pe coatin gs or lini ngs. This equipm ent can be modifi ed to e nable the probe co be utilised fo r either metalli c or non-meta lli c pip e scannmg. ln prin cipl e, the system works by inducing eddy curre nts to flow in close proximity to the tran smitter. ln a m etallic pipe these eddy currents 111igrate 111ith ti111e allowing a co mpl ete profil e of the steel pipe to be obtained. Data recorded in such env ironme nts ca n revea l the location of perturbations in the thickness of th e metallic pipe. With appropriate configurations, indications of fractur ing can also be detected (F igure 1).

The Wa ve I111peda11ce Probe (WJP) is a fu rther development w hi ch can be applied to no n- meta ll ic pipes. Larger eddy currents, or e lectromagnetic fields, are indu ced w ithin t he e mb edding material. Informa tion is derived relatin g to the composi tio n of th e host material ; soil mo isture content, deco nsolidation and voiding. MAPs are now being applied to the st udy and assessment o f ferrous water ma ins, sewers an d gas supply pipes. Probes can be made available for both surface and in- pi pe systems. T o date surveys have been conducted through coatings and linings in excess of200m m. The application of this technology to engineeri ng stru ctu re seems boundless.

Figures 2 and 3 depict two applications of BEM .

Case Study: Redcliffe City Council Water and Sewer Main Condition Assessment The condition assessment projec t described below was the result of the forwa rd planning of the R edcliffe City Counc il, who, as the asset owners, sought to ensu re that they would be able to suppl y water to, and sewerage from, their comm unit y con tinuou s l y, minimising the risk of unexpected hazards, and , at the same tim e being able to plan and budget for replacement and repair well in advance. It was the first significant asset condition evalu atio n of its type undertaken by the Council.

Figure 3. Surface BEM Scan.

58

WATER MARCH 2 003

Background The project involved two pipelines of approximately 25kms in total running through the city of R edcliffe, just north of Brisbane, as shown in Figure 4. One of the pipelines is a 600111111 diameter Mild Steel Cem ent Lined water


PIPELINE

supply line with a pipe wall th ickness of 7.0m m fro m the Pine Rivers Wa ter Autho rity in Petri e; the o th er a 500 111111 Mild Steel Cement Lined sewer line, w ith a pipe wall thickness of7.0mm wh ich runs throu g ho ut th e city. T h e water supply lin e from Pin e R ivers pro vides R edcliffe's on ly source of water. If th at pipeline were to fail , th e township would soo n b e w itho ut water as it only has reserves for abo ut 48 ho urs. T h e sewer li ne runs through most of the R.edcliffe towns hip. Th e Co un cil had beco1n e conce rned abo ut the system fol lowing a series of pipe bursts in people's backyards.

FEATURE

.!

Project Overview An integrated pipe-wall co ndition assess n1ent projec t was undertaken by the R edcliffe C ity Council from O ctober 2000 unti l M arch 2001 for th e water and sewer rising m ains located between R edcliffe and Petrie . T h is p roject sought to evaluate th e Figure 4. Geo logy ma p of Re dclifte . Blue a nd re d lines indi cate wate r a nd s ewe r extent o f external corrosion of pipe walls ma ins . using n on-destructive testing technology in the fo r m of a BEM probe and R api d M agnetic Perm eability After the pipeline rou tes were geo ph ys icall y mapp ed, Sca n n e r (RMPS) . selected borehole sa mpling and analysis was u ndertaken, to generate data fo r validation o f th e geophysical results. T ests were The R M PS is designed to m easure perturbations in magnetic undertaken to estab lish the profi le o f th e so il includin g acidity, 0ux, an d the BEM probe measures va riations in electro- magneti c distrib ution, both of w hich could be co rrelated with pi pe wa ll degradatio n. As neither pipeline system cou ld be taken o ff-line, surveys of the pipe walls we re undertaken from o utside the pi peline . Th e project was condu cted in three stages: • Firstl y, an investigation o f the environment and identifi cation o f proj ect co nstraints, • Secondly, a surface geophysics and geochemical so il assessment, ._ I and

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• T hirdly, th e no n-destru ctive pipeline testi ng. Stage One: Environment and Constraints T h e first stage o f the proj ect invo lved an in vestiga tion of th e site; establishing a feel fo r the geological environment and any areas which may pose problems fo r assessment wo rk . T his in volved ' walking' the pip elin e routes to see where they travel; under roads, people's backyards, sho pping centres and so on .

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One sectio n of pipeline was u nable to be assessed due to its location 10 m etres beneath the Bruce H ighway. Likewise, another section ra n under a main road with strip shops and som e bu il tup are as, making it impractical to u n dertake external inspections in these locatio ns. Stage Two: Surface Geophysics and Geochemical Soil Assessment

T h e second stage of the project involved a surface geophysics assess n 1ent of the condu ctivity of the so il below the su rface co determine the corrosiveness of the terrain in which the pipe is situate d . T his assessm ent w as und ertake n using a ' Geomapper' w hich sends current through th e ground to provide data abo u t the typ e of geology immediately beneath the surface. U nlike o ther con du ctivity o r resistivity techni ques the ' Geomapper ' senso rs require no direct soil co ntact . T his allows fo r a rapid survey process as well as the ability to survey areas covered by concrete or bitumen such as roads and carparks.

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59


PIPELINE

chloride, salinity and sulfate levels and descriptio ns with depths in millimetres . At the sewer pipeline failure loca tions in Redcliffe, a very stiff, pale, grey conductive clay w as found to o ccur w ith in the top fe w m etres of the soil profile. Along the water main alignment, high co nductivity response was also obtained from borehole samples collec ted at Y ebri and Gynther. Th e condu cti ve soils were believed to be a con tributo ry factor fo r the more corrosive environment which w oul d be hazardous fo r m etallic p ipes. T hese highly conductive clays tended to occur in depressions in the topography, m ost likely as a result o f salt bein g blo wn from the ocean onto land and washed, via rainwater, into the gulli es where it co llects and increases the condu ctivity o f the soil. The geophysical anom alies iden tified we re interpreted in conj unction with available boreho le information to identify prospective targets fo r detai led assessm ent o f pi pe wall co nd ition using nondestructive testin g technology.

FEATURE

Stage Three: Non-destructive Testing

Methodology

T he fi nal stage of the proj ect involved the physical testing of the pip elines. T he testin g program was carried o ut at selected locations along the 23km pipeline alignm ent w here precedi ng geochemical and geo physical investigatio ns indica ted the possible occurrence o f a corrosive geological en vironment within th e top few metres o f th e unde rl ying soil fo rmatio n. Initially som e 31 prospective locations were selected for in-situ probing requ iring pit excavation to expose the buried pipes. T ogether with scans perfo rmed on fo ur a bo ve - gro und pip e se ct ion s, t hi s accou nted fo r a total of35 sites p roposed under the proj ect. H owever, due to unfav ourable site c o n di ti o ns a n d a ccess p ro bl e m s, excavation at fi ve locatio ns cou ld no t be carried out. Apart from these, fo ur other proposed lo cations at Y ebri and Cognac were also cancelled by the C ouncil. T he w ork intended fo r these n ine rejected locati ons was replaced by additi onal scanning at various exposed pipe secti ons, with a view to assessing an y internal and external pipe corrosio n.

Prior to onsite testing, a calibration study was perfo rmed to establish the m ost suitable eq uip ment co nfiguration fo r producing reliable signal responses to detect changes in pipe wall conditi o ns. The BEM pro be and R apid Magnetic Permeabili ty Sca nn ing (R M PS) systems w ere selected beca use these ultra-sensitive instruments are capable of generating comprehensive magnetic and electromagnetic imaging Mild steel plates o f reasonably close m etallurgica l compositi on to that of the R edcliffe pipes, but of varying thicknesses, were tested to obtain a set of BEM and RMPS standard profiles for model simulations w hich were. adopted as reference for correlatio n and interp retation. T he calibration data we re later used to fabricate the state-of-th e-art sensors fo r o n-site probing. T h e on-si t e p ro bin g i n vo l ve d wrapping a pre-printed grid paper around the outside of the pipe . Using the surfa ce co nfigu ratio n the probe w as moved across the grid paper fro m. o ne crossh air to the next around the full pipe perimeter. The recorded data was then correlated

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WATER MARCH 2003


PIPELINE

aga inst the calibration results all owing signa l strength contou rs and colour gradings to represent the apparent wall thickness. P lots generated for 35 locations along t he pipeline t hrougho u t th e township were statistica lly analysed to provide a report t hat indicated the average level of corrosion along the entire pipeli ne .

Results On the basis of the results obtained , it was found that, except fo r the sewer pipes scan n ed i n Paradise Park and the Buc ki ngham-C hartwell Streets intersect ion , th e ferrou s pipes su rveyed in all o ther locations ex hibited no appreciable loss of ferrous mate rial. The stab le condition of the pipes was most likely du e to the protec tive coating, without which rhe effect of aggressive soils could have bee n m ore pervasive. Th e test results of sewer pipes in Paradise Park showed co m parative ly mo re anomalies attributable to a significan t red uction in material integrity . In this case fe rrous material loss of up to 20% was noted.

·n,

FEATURE

Similar anomalies were observed on sewer pipe secti ons surveyed near the Buc kingham-C hartwell Streets intersection suggesting that the pipes had been undergoing ferrous material loss. It was t herefore inferred th at the structu ral integrity of the sewer p ipes at these locations was less stab le, with indications of possible pipe wall thinn ing up to 1.5mm. Altho ugh by no mea ns wa rranting urge nt rem edial work, it was recommended that these pipes be closely monitored with an appropriate pressure co ntrol syste m , part ic ul arly w h e n subjected to unregulated flow rate fl uctuations under lo ad. W i th regard to the probing of pipes located at the surface, the results obtained did not indicate an y likely occurrence of hazardous corrosion patterns either internally , or externaLly, except for some indications of dep ressed fe rrous m e tal intensity delineated along sections of water pipes near salt water creeks beyond Gynth er Road. As th ese pip es are c urre ntly not protected w ith coating, it was recomme nded that appropriate

coating be appli ed in order to extend the life of operation agai nst a natu rall y more salty enviro n ment.

Conclusion A pipeli ne collapse may brin g abo ut significant undesirable financial, environm ental and social consequ ences and yet ma intenance of pipeline infrastructure need not be a costly exercise. Using the latest in non-destructive techniques, an effective condition assessment program o ffers bo th a practical and cost-effective approach to target the maintenance do llar further. For R edcli ffe C ity Council, even a limited budget e nabled them to put a life o n their pipes as a basis for rehabilitation or replacement of affected po rtions.

The Author Martin Roubal is the Managing Director of R ock So lid P ty Ltd, a M e lbou rn e-based company whi c h conducts pipe condition surveys using MAP technology developed by its research arm . mroubal@rocksolidgroup . com .au, Ph (03) 9888 0033, 11 Evans St, Burwood Vic 3 125.

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D

PIPELINE

FEATURE

WHAT CAUSES CUSTOMER COMPLAINTS ABOUT DISCOLOURED DRINKING WATER? RA Prince, I Goulter, G Ryan Abst ract This paper reports on the initial phase of an investigation on discoloured water form ation using custo mer complaints and continuous online monitoring of flo w rate and turbidity. It is be ing carried out in a wa t er quality zone comprising th e Wantirna and Knox outer suburbs of M elbourne suppli ed with unfiltered water from the Silvan Reservoir. Particulate matter from sources external and internal to the water distribution system collects on pipe walls via sedimentation and electrochemi cal particle fo rces under low velo city conditions and is entrained w hen a critical velocity is exceeded. The level of discolouration at which a customer will complain is somewhat subjecti ve, being dependent on their expec tations and their historical experien ce. It was found that the number of customer co mplaints in creased w ith air temperacure and to a lesser extent with the flow rate recorded at the service reservoir supplying the water quality zone. Cleaning mains in a water quality zone has so me effect in reducing the number of complaints in the following year.

Introduction Water quality changes occur in the distribution system. These changes may lead to the fo rmation of discoloured water, which although rare, form the greatest prop ortion of customer complaints received by water retail companies in Australia and many parts of the world. The key t o reducing the numb e r of Discoloured Water C ustomer Complaints (DWCC) is in understanding how discoloured water is formed and w hy custon1ers corn.plain. [n Melbourne, Australia discoloured water is usually a brown or yellow colour and has been attributed to colloidal particulate material, rather than natural organic matter. The primary m etho d of addressing dirty water has been to counteract sediment accumulation through mains cleaning ac tivities (Stephenson 1989). The cost of these activities is in the ord er of hundreds of thousands of do llars 62

WATER MARC H 2003

f

0

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0

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(1) Collection at low velocity times

(2) Entrain ment above critical velocity

Figure 1 . Formation of discoloured water (1) particles co llecting via sedimentation or attraction to the pipe wall at low water velocit ies; (2) entrainment of particles into the wat er stream when a critica l velocity is reached at the pipe wal l.

per year. Thus it would be beneficial to more precisely target cleaning programs or develop self-cleaning devices that are based on impro ved understanding of actu al conditions w ithin the system. Whilst this paper draws on observations from an unfiltered M elbourne drinking water system, it provides approaches that are applicable to many reticulated wa ter supplies. DWCCs are an issue for both a filte red and unfiltered systems, as particles can be gene rated within the distribution system as well as entering it from so urce water.

Collection ¡ suspension philosophy Particles can enter the water distribution system fro m source water (Yarra Valley Water 1999); (Lin and Coller 1997); (Gauthier and others 1999) and treatment (Gauthier and others 2001) . H owever material can also be generated w ithin the water distribution system itself from pipe and fitting corrosion, erosion (S tephenson 1989), biological growth (Stephenson 1989; C lark and others 1993; Gauthier and o th ers 1996; Bru none and ochers 2000; Gauthier et al. 2001; Prince and others 2001), external contamination such as durin g pipe repairs (Gauthier et al. 1996), and chemical reactions suc h as th e formation of iron or manganese oxides (Gauthier et al. 1996; Lin and Coller 1997); (Walski 1991); (Sly and others 1989); (Stephenson 1989) . H owever this material is rarely generated at a rate that can be

seen , and needs to be concentrated by hydraulic conditi ons to cause a problem. It is generally accepted in literatu re that the process shown in Figure 1 forms discoloured water at a concentration that the customers can see. The particulate material (1) is collected on the pipe walls via sedin1encation and electrochemical interactions at an tecedent events of low water velocities and (2) is then entrained into the water stream at a co ncentration that customers can see w hen a critical velocity (related to shear stress at the pipe wall) has been exceeded (Walski 1991); (Boxall and others 2001); (Prince et al. 2001). The frequency of an even t is due to the freq uency of the critical velocity accedence, and the severity is due to the amount of material that has accumulated. If th e critical velocity is exceeded freq uently, this will have a self-cleaning affect on the pipe. If the critical velocity is never achieved entrainment of material should not occur, and no customer complaints would resu lt. As suc h , discoloured water events are episodic and transient, and predicting where these events will occur is difficult (Boxall et al. 2001);(Walski 1991). Based on the laboratory observations and measurements m ade by CS [RO (Grainger et al. 2002), and Swinburne University of Technology M echanical Engineering students Qohnson and Gianchino 2000; Langford et al. 1999) the majority of particles within the water distribution system in Melbourne are likely


Tel: 02 9925 8500 (Sydney) or 08 8238 5000 (Adelaide)


PIPELINE

FEATURE

Customer Complaint to be of small size and high clay MS 1 - upstream of tanks Data Collection content and fo rm a cohesive layer on the surface of the water Since its formation in 1995 MS 2 - downstream of ta nks mains. Within this context there South East Water Limited has may be some loose deposits of collected data on Discoloured MS3 larger pa rticles (above 30 (m), Water C ustom.er Complaints however the dominant force MS4 (DWCC). T his process of will be cohesion due to electrocollection is shown in Figure 3. chemical interactions. MSS The date recorded fo r a It is generally accepted that complaint is the day on w hich a cohesive layer begins to signifMS6 the custo1ner rang th e water i ca ntl y e r ode whe n authority and not necessarily hydrodynamic forces at the the day on w hich the customer water - layer interface exceed a received discolo ured water. critical shear stress ('tc) (Black et Each DWCC is investigated Figure 2. Skeletonised depiction of Wantirna WQZ showing al. 2002) . After this threshold has and if a likely cause of the Continuous Online Monitoring Site (MS) locations. been reac he d, erosio n will complain t is found it is continue u ntil equilibrium has recorded in the database. In 1. A statistical analysis was condu cted of again been reached between the hydroundertaking thi s analysis complaints that historical customer complaints for the dynamic fo rces (approximated by the shear were attribu ted to internal building whole of the Sou th East Water Lim ited stress at the pipe wall, 'to) and the resisting p lu mbing or eve nts th at occurred region Qune 1996 to J uly 2002); force (dominantly attributable to cohesion 2. Graphical and statistical analysis of upstream_ of Wantirna R eservoir were layer shear strength) (Black et al. 2002) . excluded, as the study is concentrated on continuous online monitoring measureSuch that: discoloured water that was formed within ments of flow and turbidity was conducted 'to < 'tc, no erosion the water distributi on system. (March 200 1 to J une 2002) for a single '!o > 'tc, erosion at ÂŁ w hich may or may wate r qua lity zone co mp rising the Link to temperature and high flow not be dependent on '!o, Wantirna and Knox o uter suburbs of Figure 4 shows a strong relatio nship (r2 until '!o = 'tc or until there is no material M elbourne supplied with unfiltered water = 0.8 1) between maximum air temperleft to entrain. fro m the Silvan R eservo ir. ature that occurred on a given day and 'tc for non-cohesive sediments can be Figure 2 shows a skeletonised depiction average daily DWCC using DWCC for determined sufficiently accurately be of the Wantirna W ater Quality Zone the whole ofSEWL region (1997 - 2000) . using one of the versions of the Shields (WQZ ) used as the study area. This This trend indica tes mo re complaints can function from knowledge of grain density particular WQZ was targeted because it be expected on days reaching high and size and fluid properties. However is a small, self contained, hydraulically temperatures. Although this link is strong, an alytical exp ressions for cohes ive simple reticulation system usually fed from and generally high water demand is sediments have yet to be developed being one direction through reservoir tanks. It known to occur on high temperature days a more complex rela tionship dependen t has an above average rate of 6.0 (r2 = 0.55), the conclusion that high flo ws on particle weight, frictional interlocking discoloured water customer complaints per of grain aggregates and cohesion, and need cause discoloured water events cannot be 1000 properties per annum (Average for to be determined experimentally (Black directly drawn as o ther factors are South East Water is 3.4). Wantirna is et al, 2002) . What is known is that contributing to the relationship. Under suppli ed by Silvan re servoir, which co hesive bonds between particles at the th ese high te mp erature c onditions historically has had the highest turbidity pipe wall result in a shear strength customers use th e water in a more visible readings of Melbourne 's major reservoirs greater than that would be determined by form (i. e . drinking m o re water or filling (0.7 - 2.3 N TU) (Prince et al. 2001) where only the self-weight of the particle. swimming pools) and therefore observe the water is dosed with ch lorine, fluo ride R eynolds numbers (Re) in water the discoloured water event rath er than and lime. mains are typically turbulent (R e > 4000) . have it pass without noti ce. The system is rib-cage-like with a Discoloured water is no t a common An indication of the relationship backbone of 450 111111 mains (Figure 2: occurrence, it is therefore expected that between higher velocities (and therefore depicted in red) and ribs of300 to 40 mm re-suspension of the cohesive layer is not shear stresses) in the mains and the pipes. The Wantirna system supplied 8890 related to the change from laminar to fonnation of discoloured w ater can be properties in 2001/2002 financial year. turbulent flo w but shear stress at the pipe tested by the assessm ent of the link T he area is predominantly residential, w all. Empirical experiments conducted by between the maximum daily water flow resulting in a variable velocity profile Langford et al (1999) fou nd no link through the system. M ost of the system_ rate entering into a WQZ from the service between initial particle movem ent and the reservoirs and the DWCC that occu rred was constructed later than 1977 and the R eynolds number. in that WQZ. T o conduct this analysis fo r whole system is lined, either with seal the whole ofSEWL region would require coated concrete (75 %) , or PVC. The Study extracting daily maximum The water distribution flow rates at the entrance of Actio ns assigned in DWCC details are Customer system managed by South each WQZ, whic h was response to DWCC rings SEWL logged on the East Water Limited, o ne of arc recorded in the C ustomer Complaint beyond the scope of this database. Database the water retail companies in study. M elbourne, was used to For the Wantirna WQZ gain an understanding of Figure 3. Process followed to collect details of DWCC in the Figure 5 shows a poor linear discoloured water forma tion. Customer Complaint Database. 64

WATER MARCH 2003


PIPELINE

relationship between average daily number of DWCC and the maxim u m daily tlow rate as measured at MS2 (R 2 = 0 .24). H owever if 0-4 Ml/ d range is ignored a m ediu m strength linear relationship was observed (R 2 = 0.76). This pheno menon may indicate that maximum daily flow rate for a WQZ is too general an indicator fo r the fo rmation of discolo ured water and D WCC. Local hydra uli c conditions may play a strong role in discoloured wate r fo rmation , and these w ill be in vestigated in fut u re studi es.

On a regular basis, m uch of a WQZ is cleaned in a syste matic way by airsco urin g or flushing of mains using the tech n ique of block mains clean in g. To investigate th e long-term effectiven ess of block mains clean ing programs in reducing D WCC, yearly complaints per lOOO properties were evaluated and co mpared w ith years in w hi ch it was known that block cleaning was conducted for each WQZ. It is assumed that if block cleani ng is effective there wi ll be a reduction in th e co mplaints per 1000 properti es in the fo ll owing year. As shown in Table 1, column 2, there is co n sistency in that approximately 2/3 of the zones cleaned showed a red uction in custo mer co mpl aints in the fo llowi ng year o n a regular basis. However, it shou ld be n oted that (i) as shown in co lumn 3, it app ea rs that complaints reduced fo r a numb e r of facto rs besides clea ni ng, altho u gh in certain years cleaning w as the dominant factor in reducing co mpl ain t nu mbers, th e reaso n for the change in overall effecti veness of cleaning cou ld be related to number of zones cleaned o r the nature of the sou rce water to that zone (i.e. th e re may be certain zones that had bette r source water, or c hange in supply

Table 1. Relationshi p between WQZ block cleani ng and reductions in com pl aints the following yea r.

96/97 97/98 98/ 99 99/00 00/ 01

Pelc

71% 67% 67% 60% 63%

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10

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5-9

10-14

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20-24

25-29

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35-39

40 -44

Max imum Dai l y Ai r Te m pera tu re (Celsius)

Figure 4. Average daily number of DWCC for whole of SEWL region for a given maximum daily air tem perature (Jan 1997-Dec 2000) showing a clear trend.

Flushing effectiveness

Year

FEATURE

in the year of analysis); (ii) co m plaints for many zones in creased the fo ll owing year despi te clean in g progra ms. Accurate and assessable records on exact times of block flush ing were not avai lable fo r a more detailed monthly o r dail y analysis. Due tO th e su bjective n ature o f c ustom er co mplaints th ere is need for an u nb iased con ti nu ous measu rement of w hat the customer is seeing.

Continuous Online Monitoring Continu o us O nli ne M on itoring is needed to capture readings of a discoloured wate r event, as the events are rare and unlikely to be captured with grab sampling, pa rticularly w ith the li ttle that is known about discoloured water fo rmation. Figure 2 shows the location of moni toring sites (MS) m easuring flow rate and tu rbidity in the Wantirna WQZ. T he locati ons of the sites were c hosen to m aximize th e coverage of the Wantirna system w hile ma in tainin g the abili ty to moni tor the m ovement o f the discolo u red water throu gh the system. All monitoring sites are located on 450 111111 mains. T urbid ity is a measure of the extent a bea m of light is scattered by the suspended matter w ithin water. This defini tion means that the measurement is not quantitative, as it does not indicate the number of particles 0 .4

pR CAC

36% 59% 38% 86% 29%

Pelc = represents only cleaned zones, giving the percentage of cleaned zones where a reduction in customer complaints was observed. PRcAc = represents all zones where a reduction in complaints was observed, giving the percentage of zones where that reduction was attributable to cleaning.

present. It is a qua li tative measure indica ting the overall exte nt of cloudiness or muddiness of the water. The Australian D rinking Water Guidelines (ADWG, 1996) reco mme nd that tu rb id ity in drinking water be kept below 5 N TU for aesthetic considerations (NHMR.C , 1996). R..esearch conducted by KIW A Research and Consulting in the N etherlands (Slaats 2002) confirms that at this leve l, many customers w ill begin to notice discoloured water in a w hite, 2-litre bowl. Moni t oring Sites l and 2 we re M e lbourne Water owned and operated. So uth East Water Limi ted owned and operated monitoring Sites 3-6. AJl stations used t h e H ach 1720D low range turbidi rneter, w hi ch is accurate at low turbidities from O to 40 NTU . It has an intern al bubble trap to elimjnate fa lse readings due to air in the main. Th e turbidity meters were cleaned and calibrated every two weeks to ensure accuracy of the m eters as som e algae growth occurred within the turbid ity meter. For flow determ inatio n three types of meters were used. MS 1 had an Ultrasonic device and MS 2 had an orifice plate device. T he remainder of the stations used a Great Lakes Instruments propell er meter. T his meter was chosen for its high accuracy at low and high flows and low installation costs.

(.)

3'; C

...,

0.35 0.3

:?- 0.25 C

.,"'['! >

<(

0.2 0 .15 0.1 0.05 0 0-4

5-9

10-14

15-19

20-24

25-29

30 -34

35-39

40-44

Daily Max imum Fl ow Rate (M l/d )

Figure 5 . Relationship of maximum daily flow rate recorded at MS2 and average daily DWCC for Wantirna Water Quality Zone (Jan 1997 to Dec 2000).

WATER MARCH 2003

65


PIPELINE

On-line testing results Continuous O nline Monitming results, th e O p e rati o n s D a ta bas e , and th e C ustomer Complaint D atabase were used to build a picture of what occurred to cause a discoloured water event. In th e case shown in Figure 6, it was recorded in the Operations D atabase that a learne r drive r ran over a hydrant between MS 5 and MS 6 resulting in a sudden increase in velocity in the wa te r main above this point. The hydrant was repaired , ending with the water main being flushed. T he main was running very turbule nt before the event, for example at MS5 the velocity was approximately 0 .15 111/s in a 450 mm ID main giving a R eynolds number greater than 67,000) At th e time of the burst hydrant a turbidit y sp i k e w as g e n era t e d at M onitoring Sites 3, 4 , and 5, but no t at M onitoring Site 6 as this was downstream of the event. The results indicate that these spikes were gen erated fr om material co lle cted w ith in th e system, as th e turbidity generation was instantaneous, not all owing for travel time of a spike . T his indicates that for th is event the critical velocity 0f c) was between 0 .8 1 m /s (MS3) and 0 .47 m/s (MS5). Seven hours later, a portion of the turbidi ty spike arrived at Mo nitoring Site 6. l t is likely that so me of the material ca using the turbidity spike settl ed again befo re arriving at Monitoring Site 6 due to th e lo w overnight flo ws recorded . T he turbidity spike was largest at Monitoring Site 5 and decreased in severity at the Monitorin g Sites upstream. T his is likely to be a result ofless mate rial being present at M o nitorin g Site 3 and 4 due to the self cleaning action of the higher daily average flows that occu r at these sites. A customer complaint was recorded in the part of the distribution system supplied by off-takes between M onito1ing Site 4 and

FEATURE

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Figure 6. Discoloured water event occurring on the 23/8/ 0 1 captured by continuous on li ne monitoring of flow and turbidity. Dotted line indicates t he guideline turbidity value for aestheti c considerations. ST = spike turbidit y, which is the tu rb idity reading - the background turbid ity reading. V = wate r ve locity. Numbers in brackets indicat e the monitoring site.

M onitoring Site 5 during the event. It can be seen that turbidity in the 450 mm main betwee n these sites exceeded the recomme nded aestheti c gu idelin e value of 5 NT U fo r a 1.5 hour period after the event.

Conclusions Disc oloured wate r is ca used by a critical velocity being exceeded in a water main and that the severity o f that event is du e to the amount of material that is available that wi!J entrain at that velocity. T he results of analysis o f a turbidity spi ke captured by continuous online monitoring, and custom er co mplaints being m ore likely to occur on hot days and days of high demand is consiste nt with this. However, o ther va riables co me into p lay an d co mplicate an analysis of discoloured water customer com plaints. A customer complaint is subjective, being dep endent on the customer being able to see the discoloured water, as welJ as the expectation and histori cal experience o f the customer.

Bloc k cleaning of a whole W ater Quality Z one co nsistently reduced the o ccurrence of complaints the fo llowing year in over 60 % of cases. The work discussed h ere is an introdu ction to the issue to discolou red water prediction. C urrent work being conducted by Prin ce using the data described in this paper 1s: • D e te rmining th e m inimum critical velocity and therefo re th e critical sh ear stress required to cause a discoloured water event to occur. • T he effect of the duration of antecedent events o n th e severity of a disc olo ured water event . • The role of operatio ns changes on discoloured water form ation.

Acknowledgements T he authors acknowledge the support and assistance given by staff from South East Water Limited in undertaking this

ormation www.awaozwater.net or Quitz Event Management on tel. (02) 9410 1302 WATER MARCH 2003

-

0

0.0

Ozwater Convention & Exhibition 6-10 April 2003

66

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1.0 0 .9


PIPELINE

investigation, particularly M r. John H earn , Mr. D any l Nish, Mr. David Norris, and Dr Teny Anderson. South East Water and M elbourne Water sponsored the installation and maintenance of turbidity and flow rate continuo us online mo nitoring stations in Wantirna Water Quality Zone.

The Authors Rachael Prince is a Victmia Fellowship winner (2002) and a PhD student at Swinburne University of T echnology, School of Engineering and Science (email: rprince@swin. edu .au , PO Box 218, H awthorn, Victoria, 3122). Prof. Ian Goulter is Vice Chancellor of C harles Sturt U niversity. Greg Ryan is W ater Quality Manager of South East Water Lirni ted.

Reference List Black K S, Tolhurst T J, Paterson D M and H agerthey S E (2002) . "Working w ith Natural Cohesive Sediments." jo11mnl of H ydraulic E11gi11eeri11g, 128(1), 2-8. Boxali J B, Skipworth P J and Saul A J ( 2001 ). " A novel approach to modelling sediment movement in distribution mains based on particle characteristics." CCWI Conference. Brunon e B, Karney B W, Mecarelli M and Ferrante M (2000). " Velocity Profiles and U nsteady Pipe Friction In Tra nsien t Flow." Jo11mnl of Water R esources Pla111ii11g a11d Mn 11age111e111, 126(4) , 236-244.

FEATURE

Clark R M, Grayman W M , Males R M and H ess A F (1993). " Modeling Contamination Propagation in Drinking Water Distribution Systems." Jo11mnl of E11viro11111e11tnl E11gi11eeri11_~, ASCE, 119(2), 349-354. Gauthie r V, Barbeau B, Millette R , and Prevost M (2001). "Suspended Particles in the d1inking Water of two D isnibution Systems." vllnter Science mtd Tec/11iology: Minter Supply, 1(4), 237-245. Gauthie r V, Gerard B, Portal J M , Block ] C and Gate! D (1999). "Organic Matte r as Loose Deposits in a Drinking Water Distribution System." Water Research, 33(4), 101 4-!026. Gauthier V, R osin C, Mathieu L, Portal J M , Block J C, Chaix P and Gate! D. (1996). "Characterization of the deposits in d rinking water distribution systems." Proceedings of the Water Quality T echnology Confere nce Of American Water Works Associati on. Grainger C, Wu J, Nguyen B V, Ryan G, Jayaratne A and Mathes P. (2002). " Particles in Water Distribution System 4th Progress R eport; Part 1: Settling, R e-suspension and Transport." Rep. No . Project Num ber 4.3.6, CR C or ¡water Q uality and Treatment, M elbourne, Australia. Johnson A. and Gianchino D (2000) . "Bachelor of Engi neering (Mechanical) Final Major Project Report: l nvestigation into the causes of turbidity in municipal water supplies." Rep. No. Project ID HVW8, Swinburne University of T echnology, Melbourne, Australia. Langford E, McGilton Sand Plumridge S (1999). "B ache lor of M echani cal Engi neering H ES5300 M ajor Project: T urbidi ty

Investigation in court bowls." Swinburne University of T echnology, Me lbourne, Australia. Lin J and Coller B A (1997). "A luminum in a water supply, Part 3: Domestic T ap Waters." Warer, 11 - 13. Prince R., Goulter I and R yan G. (2001). "R.elationship Between Velocity Profiles And Turbidity Problems In Distribution Systems." World Water and Environmental R esources Congress, American Water Works Association, O rlando, Florida. Slaats N. (2002). " Processes involved in generation of discoloured water (unpublished draft]." R.ep. No. KOA 02.058, American Water Wo r ks Assoc iatio n R.esearch Foundation / Kiwa, The Netherlands. Sly L I, Hodgkinson M C and Arunpairojana V ( I 989) J ournal C IO2 : Deposition of Manganese in Drinking Water Distribution System. www.clo2.com/reading/drinking/ system. html !accessed 27;¡11/00]. Stephe nson G (1989) . " R.cm oving Loose Deposits From Water Mains: Operational G uideli nes, A Source Docu ment For T he Water Mains R.ehabilitacion Manual. " W ater R esearch Centre, Swadon. UK. Walski T M (1991). " Understanding Solids Transport in Wate r Distribution Systems." Proceedings Water Q uality Modelling In Distribution Systems, AWW A R esearch Foundatio n, USA, pp 305-309. Yarra ValJey Water (1999). " Discussion Paper: Dirty Water Complaints in Courts and Dead End Streets [Unpublished Draft]." Yarra Valley Water, Melbo urne, Australia.

WATER MARCH 2003

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FEATURE

SOME PIPELINES IN THE PIPELINE Report by EA (Bob) Swinton What's going on around the nation' Th e answer ... very little in rega rd to potable water, mainly wastewater and recycl ing of treated effi uent.

SYDNEY

The lllawarra Wastewater Strategy This is a 20 year plan to improve wastewater management on the NSW South Coast, with a budget of $197 m. SWC has awa rded the lWWS Proj ect to a Walter-Vivendi Joint Venture. Wastewater from Bellambi and Port Kembla catchments will be transferred to Wollongong ST P for terti ary treatment or re- use. Over 20 ML per day wi ll be diverted to BHP steel works, redu cing their use of potable water by 20%. Bellambi and Port Kembla STPs will be co nverted to sp ecialised storm flow plants only, with sufficient intermediate storage so that discharge to the ocean after UV disinfection will on ly be for an estimated 2% of time. The pipelines

Bellambi to WoUongo ng 10 km of750 M SCL Port Kernbla to Wollongong. 7 km of 600-750mm MSCL Both ma ins incorporate H orizontal Directional Dri lling sections utilising 7 10 mm butt-welded PE pipe: 1.3 km

111111

Photograph of the Wokalup Scheme courtesy of GHD.

under Port Kernba Harbour and Hill 60 and 1. 9 km betwee n Bellarnbi and Wollongong. An ocean outfall will disc harge no nreuse flows off W ollo ngo ng. It will run for 1 km, to 20 111 depth and consist of twin 1067 OD PE pipes, which in the surf zone will be stabilised by concrete coUars. The ultimate capacity will be 380 ML/ d of tertiary treated effiuent. From irifor111atio11 rnpplied by Jeff Brown a11d John B11tow (SWC) with lvlic/,ae/ Bamfield and Rob Pearson of WalterVive11di J oi11t Veuture.

The Georges River Program This proj ect is part of Sydney Water's WaterP/an 21, the overall long-term strategy for sustainabl e and integrated water services. Sydney Water is proposing to build a 50km 1 m diam eter recycled water pipeline (see map). le would be built mostly underground and cany 100 ML/ d of recycl ed water. If fully utilised, this would more than treble Sydney Water's current recycled water provision and bring the total proportion of Sydney's wastewater that is recycled from around 2.5% to 10%.

Serving the municipal, process, environmental and food industries throughout Australia and New Zealand

r=-:J w~ c:..::.J PCM

~ water E-mail: mail@pumpability.com

~= 68

Website : www.pumpability.com

sludge wastewater

PUMPIJJ!i3D/1D'f!W I

Port Macquarie: Tel. (02) 6581 0744, Fax. (02) 6581 0790 ¡ Melbourne: Tel. (03) 9703 2044, Fax. (03) 9703 2699

WATER MARCH 2003


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FEATURE

The need for the program The population of Sydney is growing at a rapid rate. In the Hoxton Park area, 33 km south-west of Sydney's central business district, it is estimated that the population will increase from 40,000 people to 140,000 by 2026. T his equates to 20-25 houses per week fo r the next 20 years . Currently, sewage from H oxton Park and surro unding areas is pumped to the SWSOOS (southern and western suburbs ocean o u tfall sewer) and travels to Malabar sewage treatmen t plant on the coast. T his arrangement is run ning out of capacity as a result of this urban growth . Along the way, the SWSOOS collects wastewater from other areas of so uthern Sydney whe re it is then treated at M alabar and released via an ocean outfalJ.

Georges Rive r Program map.

In very wet weather, the system and t reatmen t p lants at Liverpoo l and Glenfield allow excess sewage (mixed with rainwater ingress) to overflow into the Georges River. The N ew South Wales Environment Protection Authority (EPA) has tigh tened its regulations. Sydney Water's licence with the EPA states that there m ust be no overflows in dry weather, and existin g wet weather

system performance must be maintained in the short term. As the popu lation of Sydney's south- west grows, the existing trea tm.en t pla n ts at Gle n fi eld an d Liverpool will not be able to comply with the licence. A solution was needed tha t was sustainable and would minimise the irn.pact of development on the Georges

R iver and M alabar sewage treatm ent plant. The solution

Sydney Water developed a solution that answered these problems . The plan is to be delivered in two stages over the next six years. T he staged approach ensures that works are delivered in time

Leading supplier to NSW Government (Contract 755) since 1998

Success ,hrougb

Specialist Provider of Professional & Technical Personnel

Partnership

JWP

Engineers

o Advanced Water Treatment

Architectural Technicians

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Project Managers & Engineers

o Water Re cycling o Infrastructure Planning & Modelling

Estimators & Quantity Surveyors

o Asset Solutions

Surveyors & Registered Surveyors

o Strategic Planning &

Developer Charges For Information, p l ease contact: Selwyn Mcfaul in Brisbane on 07 3244 9600 (s.mcfaul@jwp.com.au) Gidi Azar in Sydney on 02 9460 1855 (g.azar@jwp.com.au) Terry Seymour in To wnsvi ll e on 07 4725 5388 ( t.s eymour@j wp.com.au)

lohn Wilson and Partnersâ&#x20AC;˘ www.jwp.com.au 70

WATER MARCH 2003

Approved supply areas are: Sydney - Newcastle - Wollongon g - Country NSW

IA

CLEXAN-PEAK PERSONNEL TEMPORARY & PERMANENT PLACEMENTS

Phone: (02) 9876 8888 Fax: (02) 9876 4888 Email: clexan@ozemail.com.au


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to meet regulatory and population growth needs whil e providing opportunities fo r innova tive design solutions at the right tim e. Th e first stage involves directing part of the wastewater flows from Hoxton Park to Li verpool sewage treatment plant (through th e W est Liverpool submain), ampli fy in g Li verpool sewage trea tm ent plant (STP), upgrading Glenfield STP and furt her improvemen t projects. Sydney Wat e r h as e ngag ed WALTER Constr u c ti on Group to und e rta ke co nstruction of this Stage On e, w hi ch co mmenced in N ovember 2002 and will finish in 2004. Constructio n techniqu es involve pipejacking and tren ching and the pi pelin e passes un der key business areas in th e Liverpool CBD. One pi peja c k of 6 70111 will be the longest atte mpted fo r Austral ia fo r a pipe of 1800mm diam eter. Stage Two is in the planning stage with de.livery proposed between 2005 - 2008. Stage 2 proposes to pipe secondary treated , di sinfec ted wastewater from the Gl enfield / Li verpo o l STP ca tchme nts across Sydney. Keep in g in the them e of recycling and reuse, part o f th e recycl ed water pipelin e will be sliplin ed or pla ced

FEATURE

inside a disused watermai n unde r several densely populated suburbs. Further upgrading and ampl ifi ca tion works at Li verpool and Glenfield ST Ps is also required wh ich will redu ce sewer overflows in wet wea th er to the G eorges River and directi ng additional wastewater flows from H ox ton Park to Liverpool STP. Parso ns Brinckhoff is assistin g Sydney Wate r in the planni ng for Stage Two and an integrated proj ect team has been form ed assess into the possible environme ncal impacts of the proposal. Potential customers are already b eing approac hed fo r an indica tion of in terest in purc hasing recycled wate r w h en it be co mes ava ilabl e. The main target markets are industiy, golf courses and local government fo r their parks and gardens, pro vidin g a drought- proof supp ly . R esidential use of the recycled water (for toilet flushing and watering gardens) is also being considered where feasible in maj or redevelopme nts. By the tim e the recycled water reaches Malabar, it is curre ntly planned that m ore than 50 percent wou ld have been used by customers. Any remaining recycled water will be disc harged to the deep ocea n

o utfa ll , along w ith treated eilluent from Malabar. The ultimate target is to h ave zero disc harge at Malabar. From i1ifo n11atio11 s11pplied by Co li11

Heath, Progra/11 Director Syd11ey Water, email Coli 11. heath @sydneywater. co 111. a11 MELBOURNE Melbou rn e W ater has a numb er of exciting programs in hand to meet a target of20% re- use of eilluent by the year 2010. Some of th em will invol ve extensive n ew pipelin es. The Eastern Treatment Plant currently disch arges effiu ent inco Bass Strait on the Morningcon Pe ninsula through a 60 k m pipeline, fr om w hi ch , for some yea rs, effiuent has been tapped for a numbe r of re-use projects along the M o rnin gton Pe ninsula. Th e next phase is the Eastern Irrigatio n Sche me, with th e construction of a pipelin e to C arrum Downs, with th e first cusrom e r be ing the new Sandhu rst C lub residential and recreational develop me nt. Initial usage w ill be 600 ML/ year co irrigate its golf courses, but the Sandh urst Club is also working cowa rds making recycled water available to gardens in 1nore than 1,850 residences throu g h

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WATER MARCH 2003

71


PIPELINE

underground irrigation, and encouraging th e use of rainwater tanks and recycled water in toilets. The next stage of th e Eastern Irrigation Scheme would in volve a new pip eline to carry recycled water from the Eastern T reatment Plant beyond the Sandh urst Club to Five Ways, south of C ranbo urne, in vo lving recycled water engineering company Ea rth T ec h. Some 50 irrigators have already signed up to connect. Up to 5,000 ML/year of recycled water w ill be made available to these irrigators per yea r, about four per cent of the Easte rn Treatm ent Plant's total efflu ent. To the west of Melbourne, a significant proportion of treated effluent from th e huge lagoons at W erribee has long been irrigated on pasture within the bounds of the plant, providing a significant source of inco me . Re-use beyond pasture is now being developed. As well as in- house crop experiments, a 400 ha parcel of land on the boundary has been made available fo r horticultural trials, the results from which will encourage local landowners to consider using recycled water. The feasibility of delivery o f the water via both local and exte nded

FEATURE

pipelin es is be in g in ves ti gat ed by M elbourne Water with the engin eering consultancy firm KBR and th e University o f M elbourne Institute of Land and Fo od R esources. This is in acco rd with th e Victorian Gove rnment's " Vision f or the IVerribee PlaillS" , a long- term plan which to a large extent w ill be based on th e availability of goo d q uality rec ycl ed wa te r. T h e W erribee Plains vision would provid e 165,000 megalitres/year of recycled water - equivalent to the Upper Yarra R eservoir - resulting in: • Supplementation of Victoria's water resources; • Significant agricultural benefits fo r the W erribee Plains, unlocking 300 sq kms of under-utilised agri cultural la nd fo r high -va lue crops such as grapes, stonefruits, horticulture, cut flowers and for estry; and • Improved flows in the W erribee Ri ver to enhance th e environmen tal valu es fo r the region that suppo rts mo re than 270 bird species. The main areas of the feasibility study include engineering, agricultural, financial, water quality and environmental consideratio ns.

M elbourn e Water's first off-site water recycling schem e in the W erribee area is providing recycled water for th e W erribee Park Golf C lub and th e Natio nal Equ estrian Centre . During a 12-month implem entatio n phase, the golf club and the equestrian centre will buy up to 160 millio n litres a year o f recycled water for irrigation . Th e pipeline is design ed to acco mmodate future requirem ents of other potential custom ers in the W erribee Tourist Precinct, including Parks Victoria (w hic h ru ns th e hi sto ri c W e rribee Mansio n) and Victoria 's Open Range Zoo. The precinct currently sources irrigation water from the W erribee River. From i1iformatio11 supplied by tl,e Water R ecycli11g gro11p at Melbo11me Hlater.

PERTH The Wokalup scheme ... not wast ewat er! Th e W ater Corpo ration of Western Australia is construc ting a concrete pipehead dam and a 10 km x DN1200 'SINTAKOTE' m.ild steel cement m ortarlined pipeline to transfer water by gravity flow fro m W okalup C reek to the Harvey Dam, which supplies water to irrigators in th e H arvey area.

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Th e W ate r Co rpora tion commissio n ed G H D to comp le te des ign and doc um entati o n of the proposed wo rks, and to ca rry o ut th e re quire d survey a nd ge o tec hni ca l inves ti ga tion s fo r th e proj ec t. At present th e W ater C orpo ration must re lease water fro m Stirlin g Dam, w hi ch suppli es water to the Integrated W ate r Suppl y Schem e (IWSS), to H arvey Dam to ensure that th e irrigators receive their g uaranteed alloca ti o n. Th e IWSS serves communiti es alo ng th e w est coast from Yan chep to Mandurah , includin g th e Perth m e tropo litan area, and provides source wa te r for th e Goldfi e lds and Ag ricultural W ate r Supply through to Kalgoorlie and the Great Southern T o wns W ate r Suppl y, and m uch o f t he wh eat belt. All o win g for e nvironm ental rel eases fro m the dam , it is estimated that th e available yield from th e W okalup sche m e w ill be approximate ly 10 gigalitres (G L) of w ate r per annum. As such , the schem e will enabl e an additio nal 10 CL o f w ater per annum to be transferred from Stirling Dam to th e I WSS, wh ic h represents appro ximately 3% of th e IWSS's c urre nt suppl y capac ity .

FEATURE

T he pip elin e, as well as transfe rrin g w ater fro m Wokalup C ree k to Harvey Dam , is des ign e d with provision to suppl y w ater from H arvey D am to a numbe r of irrigati o n channels alo ng th e route of the pipeline in th e event that this is required in the future. This prese nte d a number of challen ges in relation to system hydraulics. A DN750 inline fi xed co n e, sliding sleeve type regulating valve w ill be install ed to control the rate of fl o w dow n th e pipelin e, to maintain the w ate r level in Wokalup D am w ithin th e target range, and to lim it the transfer rate to a max imum of 200 m egalitres (ML) per day, to preve nt developm ent o f negative pressures in the uppe r sectio n of th e pipe line. T he syste m w ill inc lude co ntro l logi c and a numb er o f val ve inte rlo cks, fo r in stan ce, to e nsure th at th e syste m ca nno t o ve r- p r ess uri se a DN 900 regulatin g valve at H arvey Dam . Th e pipe head dam, a con crete g ravity type struc ture, w ill have a capac ity o f approxim ate ly I00 ML. The da m is 13 111 h igh, has a 75 111 lon g c entra l spill w ay (un co n troll e d ogee c res t t yp e) a nd co ntain s approximately 7000 m 3 of co nc rete. It is bein g constructed by th e

Wate r C o rporation' s C on str u c ti on Branc h using a combinatio n o f sub contractors, plant hire and in - ho use labour force. T he cost o f th e dam co nstruc tion is expec te d to be app roximately $7 million. Th e fu ll suppl y level for the dam was constrained by the need to minim ise flooding o f a road upstrea m o f the storage. This has severe ly constrain ed th e o perational ran ge of the storage, whi c h is designed to divert flows in a run- o f- ri ver operational mode . This has placed seve re con straints on th e o utl et w orks at t h e upstream end to avoid vortex fo rmation and air be ing drawn into th e outle ts. Th e proble m has bee n solved by using an anti vortex plate ove r the inle ts and setting t he o fftake pipes as low as possible in the vall ey. Co ncrete fro m th e dam will use 5560% fl yash as a repla ce me nt for ce m e nt in the mi x. Th e overall cem entiti o u s conte nt w ill be 260 kg/ m 3 and the project w ill use in excess of 1000 tonnes of fl ya sh fro m th e nea rby Muja Po wer Station. Apart fro m obviou s savings in th e cost o f th e cem e ntitious materials, the fl yash has add e d be ne fits in re du ce d heat of hyd ration , red uc ing t hermal cra cki ng

maces The force In flow.


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and reduced potential for Alkali Aggregate Reaction , a common problem that causes extensive crackin g and deterioration of concrete stru ctures in this state. This solution has an added environm ental benefit in disposing o f a waste product that would o th erwise go into landfills. In vestigation and design for th e darn structure began in August 2002 and co nstru ctio n co mm enced on site in N o vember 2002. With su ch a tight time fram e and limited site in vestigatio n it has bee n necessary to further in vesti gate and redesign the foundation as the excavatio n proceeds. This design optimisation has resulted in savings of about 15% in the volumes of concrete required for the proj ect. The proj ec t is bei ng fast- tracked, with the aim of commissioning the scheme pri or to the 2003 winter. Fro/// i1ifon11arion supplier/ by D<mg Er/gar, Pri11cipal Ci11il I E1111iro11111e11tal E11gi11eer i11 CHD's Perth ~ffice, a11rl Bob Wark, Technical Ma1 1ager of CHD 's rla//1 rlesig11 group baser/ i11 Leerlerville. rlo11g_erlgar@ghrl.co111.a11 or r111ark @ghrl.co111.a11

FEATURE

A pipe dream demolished GHD review confirms that water supply from the Kimberley to Perth is not economical. Th e vision of solving Perth' s water supply by pipi ng water down from th e tropics has been in the public arena for many years. Perth newspapers receive a steady strea m of letters praising the virtues o f such a schem e and many members of the public believe that it will open up the inland by greening the desert, solve o ur unemployment problems and give Perth a totally secure water supply. The scheme was review ed again by GHD as part of the WA Community Water Forums held in O ctober 2002. This review confirmed previous studies that th e scheme is very exp ensive. The cost of th e 300GL sc hem e would be greater than $10 billion and the delivered cost of water w ould be about $5.50 per kilo litre. T h e engin ee rin g ch a lle n ges to construct such a scheme are daunting . The first major study in the scheme was carried out by Binnie and Partners in 1988

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WATER MARCH 2003

and concluded that th e most attractive schem e was to build a dam on the Fitzroy Ri ver at Diamond Gorge, provid e controlled release down the river to an o fftake inland from Derby and pump th e water to Perth via an in land route essentially via N ewm an and Meekatharra. T he Binnie co nce pt design adopted conventional w ater industry technology using three parallel 1400dia steel pipelines and 14 booster pump statio ns. This scheme was de velop ed furth er in a 19 90 s tud y b y I nfr as tru c t ur e Developm e nt Corpo ration Pty wh o applied oil indu stry pip eline tec hnology in an attempt to reduce the cost of the scheme . Their concept comprised three parallel 1400 diameter fu lly welded steel pipes, and by using high strength steel and an operating pressure of about 700m, redu ced th e number of booster pump stations to 7. GHD 's 2002 review of the scheme was aimed at identifi ca ti o n of any new pip eline tec hnology development that cou ld lead to a reduction of cos t of the scheme and to update the cost estimates. G H D 's conclusion was th at the concept tabled by roe is at the bounds of engineerin g pra cti ce and there are m any technical issues that ha ve to be studied in more deta il , m ost with the prospect of increasing th e cost of th e project. In an attempt to minimise the cost of the scheme , the concept design allows the pipeline to run with the pump stations all op erating in se ri es simultaneously. Althou gh tec hni cally p oss ibl e, the operation of such a system withou t balancing or intermediate storages would certainly be a challenge . The concept designs also do not consider th e use of modern PE co atings of the steel pipeline and the use of high pressure rubb er ring jointed pipelines. Both these developments have the potential to improve the design of the system. Utilisation of high strength thin walled continuously welded pipe does offer the potential for lower steel tonnage but introduces loading problems o n the pipeline wh en it is empty. T he earlier studies also did not take into account th e impact of greenhouse gas resulting from such a pip eline 1840km long. T he power consumption of about 14kwh p er KL is at least three times more energy hungry than seawater desalination and this impact w ould be a m ajor hurdle in obtaining environmental clearanc e, even if the sch em e was economical. From iriforrnatio11 supplier/ by Des Boland, GHD.


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111

ENVIRONMENT

PROTECTING STREAM HEALTH: A MANAGEMENT STRATEGY R Haase, P Loose, D Clowes, U Nolte Abstract

152°50'

ln 2001, Pine River Shire Co uncil commission ed a study to assess and manage the ecological health of freshwater stream s throughout the shire using aquatic mac ro invertebrates as enviro nmental indicators. The study consisted o f four steps: (1) identify aquatic reso urces of eco lo gical significance by assessing the state of stream health , (2) identify risks and pressures affecting stream health , (3) identify managem ent responses to redu ce risks and pressures, and (4) specify a vision fo r the future state of stream h eal th . The results of all steps were e nte red into the shire's geographic in fo rmation system and translated into 'stream health management maps' . Habitat loss and eutrophica tion were found to be th e prin ci pal types of impact o n curre nt strea m conditio ns and six differe nt manage me nt to ols were id enti fi ed to maintain a nd impro ve stream health. T he strategy gives stream pro tec tio n the highest manage m e nt priority - compared to repair m easures that o fte n are mo re expe nsive and take lo nger to show an y effect. A fo llow-up n10nitoring round in fi ve years time will gauge th e ach ieved outcomes against the vision . Stream health assessm ent proved to be an excellent tool fo r the plann ing sc hem e of local go vernme nts.

Introduction U nde r the In tegrated Pl an ning Act (IP A 1997), passed by the Queensland government, the protection of biodiversity becam e an integral part of planning, and local governments are required to assess and identify natural reso11 rces or areas

~r

ecological sig 11ifica11ce . fn respo nse to the enviro nmental issues ra ised in th e IPA, Pine Rivers Shire Co uncil (no rthern neighbour of B risbane C ity) initiated a series of studies aim ed at de visin g a strategy to protect and manage the biodi versity of te rrestrial and aquatic ecosystems. One of these studies was focused on fr eshwater streams (A.F.S. 2001), being an important water resource and prominent environme ntal fea ture of the area. The shire contains over 420 km o f fresh water strea ms, all discharging into M oreton Bay. Estuarine sections were not assessed by this study .

76

WATER MARCH 2003

N

State of Stream Health in 2001

27'20'

0

5 kilometres

PINE RIVERS SHIRE COUNCIL

Figure 1 . State of stream health in the Pine Rivers Shire in 2001. Map s hows the

degree of biologica l nutrient load in freshwater streams and t he pri ncipal impacts affecting stream hea lth. See Table 1 for legend. T he aim of this study was to help decide w hich combinatio n of available resources or areas could represent the aquatic biodiversity of th e region as well as to provide the management tools needed to sustain this diversity for the future. T he method we chose to achi eve these obj ectives was an assessment of the current eco logical health of all streams across the shire based o n aquatic macroinvertebrates.

ln this con text, strea111 /,ea/ti, describes stream co nditio n in purely eco logical terms, that is, it does not in corporate socio-econom ic and cultural values . T his is in accordance with m ajor management stra t egies su c h as th e Sou t h E ast Queensland R egio nal W ater Q uali ty Managem ent Strategy or the Sustainable Rivers Audit. Bioassessm ent of streams is based o n the fact that commu niti es o f

Table 1. Pro portion of strea m health classes (degree of lo ad with biological

nutrient) over 420.8 km of fres hwat er s treams in the Pine Rivers Shi re (based on data from 76 sites sampled between 1998 and 2001). Stream health class

A (clean or traces of load) B (little loaded) C (loaded) D (strongly loaded) E (polluted) F (strongly polluted) G (excessively polluted)

Appraisal for management

Combined stream length [km]

% of total

44.5 28.9

10.5 6.9 19.5 37.5 24.1

protection required, urgently

1.5 0.0

improvement required

82 .0 157.7 101.3 6.4 0.0

length

protection required , urgently protect ion requi red tolerable condition improvement required improvement required


ENVIRONMENT

macroin vertebrates re fl ec t the ec ological health o f th e stream they live in (e.g. Norri s & Thom s 1999, Rosenbe rg & R esh ·1993) . To human impa ct, aquatic communities respond w ith a change in attributes, including spec ies ric hness, communi ty co n, positio n , c ommunity stru cture, abundan ce and ochers. W hen a stream is disturbed , for exampl e, the numb er of disturban ce-i ntolerant spec ies decreases, w hile the proportion o f tolerant species typi cally increases. In ocher w o rds "a w ildern ess area is healt hy and hum an distu rbance reduces health" (W hittingto n

152°50'

N

Stream Health Management Strategy Improve stream health Maintain stream health

2002). Under t he IPA , reso11rces or areas of ecological s(e11if,ca11ce inc lude natural assets (ec o sys te m s, ha bi ta ts, spec ies) th a t con tribute to the biolo gical di versity of a regio n and/ or are o f hi gh in st rume ntal 27"2fY va lu e (for th e qua lity of air, w ate r and soil). In regio ns, such as th e Pine Ri vers Shire, wit h a w id e ran ge of landuses and th e ir assoc iated impact on st reams, the 5 0 ecological signi6cance of aquatic resou rces kilometres can be directly ga uged by the assessm en t of stream health. H ealthy w ate rways have greater sig nifi cance as a natural resource Figure 2. Map showing management response to measures to reduce risks and th a n se v e r e ly impac te d on es . Th e pressures affecting stream health in the Pine Rivers Shire. exceptio n to th is rule is a stream section , w here in-st ream hea lth is impac te d by low-quality wate r from upstream , w hil e habitat struc ture and riparian conditio ns are excel.lent. A stream health study also covers WESTIN ENGINEERING PTV LTD th is exception , as it includes an assessm ent o f the riparian zon e. T he refo re , st ream health assessm e nt was used as an appropriate tool to manage aquatic resou rces. W e prepared this articl e to de m o nstrate the sui tability of a stream health assessm e nt o n a shire- wid e scale and its relevan ce fo r the new planning sche me (I PA) for local governments. Some asp ects of the o riginal study (bi o moni to ring, m et h ods, manage me nt tools,) are outlin ed o nly w itho ut going into detail. Th e reade r interested in more informatio n and specific data is re fe rred to the o rigin al tec hnical report (A . F.S. 2001). Currently, the scientific background data on strea m health classes are prepared fo r publicatio n ( N o lte & H aase, in prepa ration) . SCADA and Telemetry Specialists for the

• •• •• •• ••• Westin ••• Solutions Through Technology

Steps of the management strategy T he strategy to assess and m anage stream h ealth across Pine Rivers Shire comprised fo ur steps: 1. D e fi ne distinct classes o f stream healt h , determine current strea m health across the shire and ide ntify areas of ecological sig nifi can ce; 2. [dentify th e 1isks and pressures currently affecting stream health; 3. Identify m anagem ent respo nses capable of reducing these risks and pressures; 4. Specify a realistic visio n fo r the futu re state of stream hea lth (5 year pe riod). After fi ve years, a follo w-u p m o nitoring round to the baseline m o n itoring u nde rtaken in 2001, will gauge the ac hi eved o u tcom es aga inst the visio n.

Step 1: Current state of stream health and areas of ecological significance Th e first step of the managem ent strategy involved the identifi catio n and definiti o n o f distinct classes of stream healt h , and

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www.westinengineering.com.au WATER MARCH 2003

77


ENVIRONMENT

the preparation of a composite map showing the current spatial distribution of stream health classes across the Shire (Figure 1). Methods T he stream health assessment was primarily based on aquatic 1¡11acroi11vertebrates, which were sampled at 76 sites . Qualitative samples were taken fro m all major habitat types present at each site. A standard AUSRIVAS hand net (250 ~tm mesh) was used and sediment cores (105 mm diameter) were taken. Samples were immediately preserved in alcohol and entirely sorted under a stereo microscope (X 6 and X 12 magnification) in the laboratory. Taxonomic analysis of all samples was conducted to species level (with species often assigned to preliminary code names, because many aquatic invertebrates of the region have yet to be forma lly described). Identification was reviewed by experts for the respective animal grou ps, an d vouchers of all species are kept in the macroinvertebrate collection held by Applied Freshwater Science, Rocksberg, Queensland. Correct identification of spec ies is cruc ial to developing a management strategy because it is the key element in reliable and consistent stream health assessment. Stream health classification was based on biotic and abiotic variables, including estimated abundance/biomass of animals recorded at a particular site, community composition, species richness, presence and type of indicator species (if available), dissolved mrygen at the stream bottom and conductivity (A.F.S 2001). In addition to these in- stream variables, the physical state per site was assessed (Platts et al. 1983, PRSC Technical Manual 1996) and high-resolution air photos along with extensive gro und checks were e mployed to generate a stream health map (Figure 1) . The strength of the m ethod used lies in the identification of macroinvertebrates to species level. Species identification achieves the h ighest resolution power of biological in formation present at a stream site (e.g. Bailey et al. 2001, J ohnson 1995, Lenat & R esh 200 1, Nolte 2001) and opens up the avenue to identify and establish indicator species characteristic for specific environmental conditions (e.g. DIN 1987, Rosenberg & Resh 1993). A major difficulty in this study was the fact that knowledge about spec ies, their distribution, and ecological preferences and tolerances is still rather limited for Queensland's freshwaters. However, understanding of in-stream life is growing 78

WATER MARCH 2003

152°50'

N

Applied Freshwater Science

Stream Health: Vision for 2006

-

27°20'

5

0

PINE RIVERS SHIRE COUNCIL

kilometres

Figure 3. State of stream health in the Pine Rivers Shire in 2006. Prediction based on assumption that management responses to reduce impacts on stream health are implemented immediately and successfully. See Table 1 for legend.

and the extensive database Pine Ri vers Shire Council has collected over past years (biological, physical and chemical data) represents a significant contribution. Details on how biotic and abiotic metrics were used to assign strea m health classes will be published elsewhere (Nolte & Haase, in preparation). Seven stream health classes were defined in accordance with the "saprobity system" (from the Greek word for putrid) (Habeck-Troptke 1992), a scoring system that is widely used w here nutrient input (eutrophication) is the major stream pollutant Oohnson 1995, Rosenberg & Resh 1993) . This applies to the Pine R ivers Shire where rural living in the outskirts of Brisbane and grazing (horse, cattle) is the main land use in the upper and middle catchments. The saprobity system works wi t h a 7-score scale allowing to differentiate three classes of healthy (though partly impacted) streams, three classes of polluted streams suffering fro m a varying degree of eucrophication, and one in the middle that is nutrient loaded but not yet polluted (Table 1). We c h anged the original te rminology (Habeck-Troptke 1992, Rosenberg & Resh 1993) and labeled the 7 classes A to G, following the So uth East Queensland R egional Water Quality Management Strategy (1998) . H owever, the original standard colours for stream

health maps were used (Habeck-Troptke 1992, DIN 1987, 1990). Results and Discussion

Aquatic macroinvertebrates are not only a useful tool for stream health assessme nt an d stream management appraisal , but also a natural asset in their own right. Altogether 488 macroinvertebrate species were recorded. The vast majori ty were in sects, 420 species, followed by molluscs (snails and mussels), 24 species. Th e remaining 44 species belonged to distinct worm groups (e.g. flat worms, leeches), water mites and crustaceans (water fleas, shrimps, etc.). As many as 200 of the recorded species are yet to be described scientifically, evidence of our s till limit ed knowl e d ge (Fairweather & Napier 1998). Seven species were collected for the first time and are new to science. However, th e majority of the undescribed species had been collected before in the course of other studies, and som e of them even proved to be environmental indicators. A total of 15 indicator species were identified, plus a further 78 species that show a clear optimum under a certain conditions (i n either clean or p olluted waters) but have a broader ecological range, so that they are not indicators se11S11 stric/11 (Cranston 1996, Nolte (in press), A.F.S. unpublished data).


ENVIRONMENT

Stream health th roughout Pine R ivers Shire included the six hea lth classes fro m A to F. As much as 37 % of aLI stream sections were in very good to good conditio n (class A , B , C) . Ano ther 37 % were in tolerabl e co nditio n (class D ), w hile 26 % requ ired improveme nt (class E, F). T abl e 1 sho ws th e stream healt h classes w ith the respective degree of loading o f b iological nu tri ent and th e code-colo urs used in standard scream health maps (Figures 1 and 3). T able l also prese nts the nun1ber of stream kilom etres fo r each healt h cl ass, alo ng w ith an appraisa l for manage m ent. It has to be em phasised that strea m sections in very good hea lth (class A , B) re quire th e most urge nt m a nage m ent actio n , na m e ly protectio n . Anoth er target for urge nt m an age me nt are polluted (class E) and stro ngly pol luted (class F) waterways . Excessively polluted (Class G) screa m secti o ns were n ot reco rded, because th e m aj o r point po lluters (e .g. industry, se wage treatment planes) d isc harge in to the tidal reac hes of cre eks and ri vers not covered by this study. Th e spatial pattern o f strea m hea lth classes is show n in th e stream health map Figure 1. Te n a reas (st re a m sec ti o n s) o f eco logical signifi cance for the Pine R ivers Shi re w e re id entified , e ight o f them headw ate rs in the coastal range, and tw o wetlands in coastal lowlands. Five of these sites are in excellent condition (health class A) and n eed to be protected, th e othe r fi ve sites are im pacted and require both im proved managem ent and protecti on . Locations of these sites and details on their ecologica l sign ifi can ce is do cum ented in the original report (A. F.S. 2001). Th e ' da rk end ' o f the stream health scale revealed 12 severely pollu ted and degraded stream sections in urge nt need for repair. Alarmingly , nin e of these sites lie in upper and middle catchments, hence impacti n g o n exte nsive downstream reaches. T hese sites are mainly associated with rural reside ntial develo pme nt that, during the last d ecades, rapidly w o rked its w ay through upper catchm ent areas w ithout appropriate planning. (For details and m ap see A.F.S. 200 1.)

o f ripari an vegetation, caused by 3 princ ipal risks and pressures: cleari ng of native forest, grazing, and modificati on of the natural strea m chann el. E utrophication - enrich me nt of th e wa ter w ith bi olo gical nutrie nt ca used b y 4 principal risks and pressures: grazing , dairy fa rms, ferti liser/ dete rgen ts, and urban sto rm wa cer. T he spatial distribution of the principal risks and pressures across th e shire (not show n here du e to lack o f space) is doc ume nted on th e master ma p o f the o riginal report (A.F. S. 2001).

Step 3: Management response to reduce risks and pressures In the third step, streams were classified into tw o ca tegories, those in need o f protectio n w ith the aim to maintain stream health and chose in need o f repair aimed at improving stream health (Figure 2). Protecti o n mea ns continuo us ca re o f th e biodi ve rsity of a stream site to prevent (further) degradation . R epair mea ns e ithe r resto ration or re media tio n. R estoratio n aims to re turn the ecosyste m to an o riginal (Pre- Eu ropean settl ement) state. Wh en restorati o n is not possible, rem ediati o n is appropriate . Th e re medi-

Setting priorities: Stream health manageme nt should b e guid ed by prio rities to maxim ise resu l ts . T he principles fo r setting th ese priorit i es w ere protection before repair, preventio n b e for e r e pair , u p s tr ea m b e fo r e do w nstream. The protection of health y stream sectio ns (cl ass A, B, C) is o f high est priori ty: • these sectio ns are vital to th e h ealth of the entire strea m ecosystem including th e (ge n e r a ll y s tresse d a nd imp acte d ) downstream reach es. O nly a hea lt h y strea m pro vides sustain abl e ' ecosyste m services', such as a high natural wate rp u r ifyin g ca pa c ity an d a balan ce d disch arge regim e. • stream sections of class A and B are of highest biodiversity value and ecologica l significance because they house rare species and endangered habitats. These valuabl e stream sections are in a de licate ecologic al equilibrium and extremely prone to dist u rbance and degradation. Th e Joss of Class A is practically irreversible (D IN 1987) .

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Step 2: Principal risks and pressures affecting stream health As a consequence o f th e past and present land use in the P ine Rivers Shire, the maj o rity o f streams have already become degraded and polluted, w hile healthy strea m sections are at risk o f su fferin g the same fa te. In summary, c urrent land use impacts o n scream health in tw o prin cipal w ays: Habitat loss - by physical degradation o f stream bed and ban k and d egradation

ation process creates stabl e and dive rse aquatic habitats, not necessarily resem bling th e original state of the ecosyste m .

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WATER MARCH 2003

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ENVIRONMENT

• the 'domino effect' : Wh ere the health class of an upstream section decreases, the health of the downstream sections is also likely to be downgraded. • protection of streams and prevention of degradation and pollution - compared to repair - is more efficient, takes instant effect and is less expensive. H ence it fo llows that the repair of severely degraded stream s (class E, F, G) is of lower priority, though it obviously is desirable to enhance the health of as many streams as possible. T he condition of polluted streams should be improved at least to class D level. Further improvement is desirable for selected catch ments, in particu lar those feedi ng d rinking water storages .

Principal tools for management response Six principal management tools were iden tified to impl e ment measures to manage strea m hea lth: • Protect natural scream channel and riparian forest • R estrict deve lopment in key areas • Co ntrol stock access to stream s • Restore or rehab ilitate channel and riparian forest

• Prevent or reduce nutrient input • Prevent or reduce stormwater contamination D etails on where exactly to apply wh ich of the above tools are show n on a master map in the original report (A.F.S. 2001).

Step 4: Vision for the future and performance control The importan t finding of this study was that over 17% of all stream kilon, etres in the sh ire were in near-natural cond ition and of very high ecologica l va lue (class A and B) . This result was quite unexpected beca use Pine Rivers Shire lies adjacent to the City of Brisbane and is subject to a fast population growth and high development pressure . All stream sections of heal th class A and B were headwa ters (Figure 1) and require strict and imm ed iate protection , particularly beca use rural lifestyle is very popular and land development is working its way into the uppe rmost catchm ent areas . Also in need of protection are the near to 20% of stream kil ometres of class C, m ostly located in the upper to middle catchme nt areas.

A series of free one day technical seminars will be held in Brisbane, Sydney, Melbourne, Adelaide and Perth in May this year. Main topic of the seminars is Advanced Water Resource Management. Speakers will discuss wastewater reclamation , pre-filtration applications and leakage control in pipelines. For more information contact Marjoleine Lloyd on phone 08 8389 7511 or email: marj@amiad.com.au .

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Most degraded strea m sectio ns in need of repair (class E, F) were located in urban areas in the lower catchments, but were also associated with ruralresidential zo nes. T heir condition shou ld be enhanced to class D. If management ac ti on is taken straightaway and successfully, stream health may be expected to have improved by the end of 2006 as sho w n in Figure 3 . The vision can be su mmarised as follows : 1. All stream sections of health class A, B and C protected, so that their ecological va lue is ma i ntained or, for strea m s curren tly of health class C, even enhanced. 2 . No po lluted streams (Class E and F) anywhere in th e shire in future. 3 . In three selected catchments (Cedar Creek, Lak e S a m sonv a l e, Lak e l(urwongbah), th e hea lth of al l strea ms shou ld be better than class D . Th e results of the 2001 study provide th e benchmark against w hich the future sta te of stream hea lth will be gauged. The future question w hether the implem entation of the management strategy was successful a nd whether th e des ired outcomes were ac hieved, or to w hat degree they were met, can be answered by subsequent stream health assessment usin g the same methods . T he we ll known fact, however, that the region is subj ect to highly variable ra infall patterns ca n set limits to the co mpariso n of two 'snapshot' monitoring events lying years apart. To overcome this problem (i.e. to correctly explicate data from distinct years) data obtained during on-going biom onitoring proj ects in selected sub-catchments in the shire, that are based on seasonal and/or long-term annual monitoring events (e.g. A.F.S. 1998, 2002a, 20026), wilJ be taken into account. These case stud ies provide insight into discharge driven patterns of macroin vertebrate communities and should help to discern natural co mmunity patterns from manmade (impacted) patterns. Like in most natural biological system s, c h ange du e t o improved str eam management does not come overnight but needs time, so that a follow-up monitoring round with the aim to update the scream health map is recomm ended for 2006.

The Authors

Amiad Australia: Vic: 03 9439 3533, SA: 08 8389 7511 , NSW: 02 9686 7299, Qld: 07 3279 4700, WA: 08 9242 3001

80

WATER MARCH 2003

~-= Elth3m only

Dr Rainer Haase is botanist and geologist, and Dr Ulrike Nolte is limnologist and zoologist. Both authors are senior scientists and consultants with Applied Freshwater Science, Rocksberg, QLD 4510, ph. 07 549 7 0074


ENVIRONMENT

(afs @ mail.c t h . com .au ) . A . F.S. 1s specialised in biological monitoring of inland waters. Peter Loose is the Manager En vironmental Services and Daniel Clowes is the Environmenta l Planne r in the Environ m ental Services Department of the P ine R ivers Shire.

References A.F.S. ( 1998) South Pinc River: a survey of benthic macro invercebraces in space and time. T echnical report by Applied Fresh water Sc ience to Environmental Services, P R.SC, 60 pp. A.F.S. (2001) Defining and protecting resources of ecological significance: Hea lt h and biodiversity va lu es of st reams in the Pinc l<..ivers Shire, Q ld. The state in 2001. Technica l report by Applied Freshwater Science to Environmental Services, PR.SC, 79 pp. A.F.S. (2002a) Stonn water M onitoring Program N o rth La kes - Mango Hill. Bio logica l monitoring of "Tributary C". The state o f the creek in winter 2002. (M o nitoring program si nce 1999.) Technical repo rt by Applied Freshwater Science co J ohn Wilson & Partners and W orks & Services, Pl<..SC, 13 pp. A.F.S. (20006) 13iological M onico,ing of Cabbage Tree C reek , Marc h 2002. W ate rwa ys Enhancement Program C o asts & Clean Seas. (In collaboration with the " M o reton Bay Catchment Water Quality M anagement

Team " .) T ec hni cal report by Appli ed Freshwate r Science to Environm en tal Services, P R.SC, 15 pp. Bailey I<.. C, N o rris I<.. H & R eynoldson T B (2001) T axonomic resolution of benchic macroin vertebrace communities in bioassessments. J. '· A111. Be11tl,o/. Soc. 20: 280-286. Cranston P S ( I 996) Identification guide to the C hi ronomi dae o f N ew South W ales. Australian W ater T echnology Identification G uide No I, Sydney, 375pp. D IN 38410 Teil 1&2. (1987, 1990) !German Standard Me thods fo r the Assessment of Water, W astewater and Sludge: 13io logical and ecological methods. Manual for scream hea lth assessm ent. EPA Germany. I (in G erman) Fairweather P G & Napier G M ( 1998) Environmental indicato rs for Nat ional Seate of the Environment reporting- Inland waters. Fed. Dept Environme nt, Canberra. H a b c c k - T r o p fk e L . H . - H . ( I 9 9 2 ) Abwasse rbiolog i e . [Th e bi o l ogy of wastewa ter.I (i n German) Werner- Verlag, I) ,sseldorf, 256 pp. J ohnson R K ( 1995) The indicator concept in freshwater b iomo nitoring. p . 11-27 . In: C ranston P. (ed.) Chironom ids. From Genes to Ecosystems. CS IR.O Publications, EastMclbourne . Lcnat D R. & Resh V 1-1 (200 I) T axonomy and scream ecology - The benefits of gen us- and species-level identificatio ns. J. N . A111. Beutl,o/. Soc. 20: 287-298.

SIMPLE

Noice U (200 1) Wh at's in the Wate r ' Biodiversity in streams - do we really ca re? Wildlife Australia, autumn 200 1, p. 34-36. Noice U (in press) C hironomid communities arc prime indicators for stream health: A case study from southeast Queensland , Australia. C o nference Con tributi o n co the 5th Internatio nal Con gress of Diptero logy; Brisbane, October 2002. N orris R. H & Thoms MC (1999) What is ri ver health? Fresh111ater Bio/on 41 : 197- 209. Platts W S, M ehagan W F & Minshall G W ( 1983) Methods for evaluating strea m , riparian , and biotic conditions . US Dept. Ag,iculture, Forest Service, Technical R eport INT- 138, 7 1 pp. PR.S C ( 1996): Pinc River Shire Council: l<..ivers and screams monito ring progra m technical manual. Sou th Ease Queensland R egio nal Water Qual i ty Management Strategy. ( 1998) T he crew m ember's guid e co the hea lth of o ur waterways. Brisbane C ity Council, 13risban c Qld, 97 pp. R osenberg I) M & R esh V H (eds) ( 1993) Freshwater biomonitoring and benchi c macroinvcrtebraces. C hapman & Hall, N e w York and London, 488 pp. Whittington J (2002) Assessing ri ver conditi on using exist ing data. A guide fo r catchme nt managers. C RCFE Know ledge Exchange Program, CR.C fo r Freshwater Ecology River Management Series Part 2, 17 pp.

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ENVIRONMENT

REDUCING NUTRIENT RELEASE FROM SEDIMENTS: ECOLOGICAL RISKS B T Hart, S Roberts, M O'Donohue, J Taylor, E McWilliam, M Waters Abstract T he appli ca ti o n o f ac tive barri er m ate rials, suc h as calcite , clays an d zeo lites, to lake sediments is being trialled in a number of countries as a low-cost method for preventing phosphorus release for sediments, and therefore reducing the risks of algal blooms. Laboratory work has show n th at precipitated form s of calcite (CaC 0 3) are e ffective in re du c ing p h os ph o ru s re le ase fr o m an aerobi c sediments in Lake Carramar, a sm all urban lake in Melbo urne . A three-stage protocol fo r assessing the eco logica l risks ass o c iate d w ith th e possible applicatio n of an active barrier has bee n developed and applied to Lake C arramar. Four possible ecological issues were identifi ed and th ese were subjected to a q ualitative ecolog ical risk assessm e nt. There w as a high risk that a calcite layer would adversely affect the be nthic algae gro wing o n the botto m sediments of Lake Carramar, altho ugh there is a lack of information to assess the m agnitude of this effect. T here is also a moderate likelihood that a calcite barrier w ould redu ce the levels o f o ther phytoplankto n (in additio n to the targeted cyan obacteria), resulting in maj o r im plications fo r the zooplank ton populatio n , w hich dep end upon the phytoplankton fo r fo o d, and fo r the fish pop ulatio n that in turn dep ends upon the zooplankton. This poses a hig h risk to the o verall ecological h ealth of the lake. The other two issu es - toxicity of the barrier m aterial and tu rbidity increases due to the ap plication of the m aterial w ith possible impact on lig ht p e netratio n and phytopla nkton production - w ere rated as lo w risk.

Introduction M anagem ent actio ns aimed at reducing alga l blooms in lakes and wetlands generally fo c us on reducing i nputs of nutrie nts fro n1 catchment sources, such as sewage disc harges and diffuse run off from agricultural land. However, such strat egies take no account of p ossible in situ rel ease o f nutri ents from the

82

WATER MARCH 2003

Stage 1: Feasibility study Characterise lake • tlutrl ents (ccno, inputskJutpl.As , budgai} • Phytoplankton (spedas CO"l) , blonwss) • PhyS-oal (dapth, stratification} • tlutrl ent composition of ad! m.nts

Unlikely sediments a i551

Undertake laboratory bloreactor trials

with barrier material

Trlnl other methods Unlikely sediments an issue

Barrier Is possible Conduct prellmlnaryERA

Unllkoly sediments nn issue

Trial de-

No

ratification

Figure 1. Protocol for investigating t he effectiveness of active barrier fo r reducing sediment nutrient release, and for undertaking an ecological risk assessment to determine the ecological risks from the application of the barrier.

sediments. Ge ne rally, it is only w he n t he waterbo d y is stratified and the sediments become anaerobic that substantial am ounts of nutrients (particularly filterable reactive phospho rus (FR P) and ammo nia) are released. A nu m ber of m e thods are available to reduce sediment release of nutrients, including nitrate addition, artificial destratificatio n, oxygen inj ectio n and dredging (R yding & Rast, 1989 ). An alternative low-cost and lo w tec hno logy o ption

involves the appli catio n of "capping" m aterials to contami na ted sediments Qacobs & Forstner, 199 9) . T he m e thod involves the placem ent o f a co ver o ver the sedime nt to seal it off and minimise release of contaminants to the w ater column . T he co ver material may simply be a physical barrier over the sediment (e .g. sand , g ravel), o r an active ba rrie r. Ac tive barri e r sys tem s are ge ne rally p ervio us geochemical materials capable of actively dem o bilising contaminants in the

Table 1. Possible eco logical issues and assessment endpoints for use in undertaking an ecological risk assessment for active barriers. Possible ecological issues

Assessment endpoints

1. Toxicity of the barrier mat erial

No toxic effect s observed in laboratory ecotoxicity t ests

2. Increase turbid ity of water column due to barrier material not fully settling out

No increase in water col umn tu rbidity

3. Adverse effect on the benth ic algae (mostly by smothering, but possibly also be t rapping sediment nutrients)

No major change in the benth ic algae (distribution, biomass, productivity)

4. Adverse changes to the phytoplankton communities, leading to adverse foodweb effects

No major changes in the phytoplankton species distribution (apart from the desired effect of reducing cyanobacterial numbers)


ENVIRONMENT

pore water by adsorptio n of precipStage 2: Preliminary ERA itatio n processes . For exam pl e, calcite (CaCO 3) (H art et al., 2003a), Problem formulation zeolites Uacobs & Forstner, 1999) o r • Define keyecologlcal Issues • Ooflne keystressors modifi ed clays, suc h as Phosloc • ldentffy link11ges between stressors and Issues (Douglas & Coad, 1996) . • Ootermino assessment endpoints In a previous study, we showed that under anaerobic condit ions the Preliminary risk assessment sediments o f Lake Carramar, a For each Issue determine: sma ll urban lake in M e lbourn e, • Severity or effect • likelihood or erroct occurring re leased both FRP and ammonia, although there was a delay of betwee n .J. and 12 days before any Unlikely substantial amou nts of FRP were barrier technology would be accei,lible re leased (H art et al., 2002a). Th ree calc ite barrier mate rials (crushed lim estone and tw o forms of prec ipUndertake further trials and itated calcite) were tested fo r their Detailed ERA effective nes in red ucing the release of phosp ho rus from these sediments. T h e two p rec ip i tated calcite mate rials p ro ve d to be q uite Figure lb . effec tive at redu cin g the release o f algal bloo ms over rece nt years (Co lem an , phosp hor us fro m t he sediments u nd er 2000) . T his brackish lake (salinity c. 4 ppt) anaerobic conditions, w h ile th e limestone is approximately o ne hectare in area, has was ineffe cti ve. Over a 60-day period , a gent!y slo pi ng sides, a maximum d epth of 2% laye r of SoCal (a Germ an p roduct) 2.5111 and sand y sed iments. It also has re d u ced t h e amount of phosphoru s characteristics likely to influ ence algal rel eased b y alm ost I 00-tim es over th at growth including: limited shadin g causing o cc urri ng with no barrier. Th e Australian in creased light and tempe rature leve ls; product (ESCal 2%), w hile not as effective poor circu lation allowing for stratification as th e SoCal, still redu ced th e phosphorus and long water residence t im e; low rel eased by around 15-times that w ith no ab undance of aquatic macrophytes thereby barrie r (H art et al., 2003a) . limiting co mpetition for nutrie nts and In system s where the external nutrie nt ligh t; limi ted habitat fo r zooplank ton that load is small, these calcite barrier materials consu m e algae; and highl y nutrient-laden should have a beneficial e ffe ct on the in fl ows suc h as u rban scormwater and wace rbody by reduc in g the release of residential run-off sediment-associated nutrients, and thereb y re du c ing th e risk t hat cya nobacterial blooms w ill occu r. H owever, it is also possibl e t hat the addition of an active barrie r mate rial to the sediments could result in adverse ecological effects. Fo r this reason , we have d evelop ed an ecological risk assessm ent protocol spec ifica ll y to assess the possible risk of adverse ecological effects from the use of active barrier materials, and have applied this proto co l to Lake C arram ar.

The system Lake Car ramar is o ne of three interconnecting, m an- made lakes, w hich fo rm part of the Patte rson Lakes system in Carrum Downs, a suburb of M elbo urne. Lake Carra mar has a history of significan t I. Input/o utput budgets are needed to enable the relative importa nce of sedim em release to be assessed. 2. Information on stratification is needed to assess whether the bottom sedi ments will go anaerobic and ifm for how lo ng. It i, under anaerobic condition, th at the major fluxes of FRI' and N l-1,-N

Ecological risk assessment protocol Ecological risk is defin ed as th e produ ct ofche likelihood (or probability) o f so me adverse ecological e ffect o ccu rring with th e conseq uence (severity o r hazard) if chat effect does occur. Gen erall y, th ere are th ree stages in u nd e rtaking an ecologi cal risk assessment (ERA) - pro b lem formulation, risk analysis and risk characterisation (USEPA , 1998; Hart et al. 20036).

In brief, the ERA process see ks to: identify the key ecological issu es and key stressors; id entify t h e linkages between the key stressors (drive rs) and eac h ecological consequence (using a co nceptual mod e l or quantitative ecologi cal m o del), and from chis provide information o n w h ich drive rs are most sensiti ve to manage ment or contro ls, and what are th e b es t assess m ent "endpoints" to use fo r the ri sk assessment; assess the risks associated with each issue (i.e. th e likelihood that th e issue will occur and th e co nseq uences if it do es occur) as q u antitati ve ly as poss ibl e; and id e nt ify (and where po ss i b l e quantify) all m ajor un certaint ies so the d ec ision m aker can d ec ide on t he co n fiden ce that sho uld b e placed on th e informatio n. A th ree-stage protocol has b ee n develo ped for assessing the ecologica l risk assoc iated with the possible appli cati o n of an acti ve barri er (Figure ·1).

Stage 1- Initial feasibility studies Th e situation leading to a d ecision to undertake an ERA would be one w h e re a manage m e nt agency has a lake experie nci ng regu lar alg al bl ooms, and h as undertaken preli minary work to est ablished that an ac tive barrie r is a feasi bl e o ption for reducing the incidence of a lgal blooms. T his preliminary work wou ld involve (Figure 1 a): • C h aracterisin g th e maj or drivers like ly co b e responsible for th e algal bloo m s o ccurring in the lake. In parti cular, in form ation wou ld be need ed on : ann u al variation in the co ncentrations of t h e major n u trie nts (FR P, NH.i-N , NO,-N ); an n ual changes in alga l biomass via measure of Chlorophyll a; input/ output budge ts' fo r the major nutrients (TP , FRP, TN , NH.i-N , NO ,-N ); and wheth e r the system strat ifies and t h e bottom waters becom e anaerobic, and if so when in the yea r and for how lon g 2 .

Table 2. Mat rix used to estimate overall level of risks Extent of Effects

Likelihood of Exposure

1

2

3

4

5

lnsig

Minor

Moderate

M ajor

Catastrophic

A - Almost Certain

H

H

E

E

E

B - Li kely

M

H

H

E

E

C - Possible

L

M

H

H

E

D - Unlikely

L

L

M

H

H

E - Rare

L

L

L

M

H

will o ccur.

WATER MARCH 2003

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â&#x20AC;˘ Determining that the sediments will release nutrie nts (P , N ) u nder realistic conditions, particularly anaerobic co nditions; â&#x20AC;˘ D ete rm in ing that the acti ve barri er material w ill red uce t he nutrient re lease under these conditio ns. T he latter two ste ps would in volve undertaking labo ra tory bioreactor experime nts of the type described by H art et al. (2002a). Stage 2: Preliminary ERA In the event that the preli1n inmy testing has sho wn th at use o f a barrier is feas ibl e, a preliminary ER..A should be undertaken. T he first phase of an ERA , to adequately formu late th e proble m involves three main steps (Figure lb): id entify the key ecological issues and key stressors, identify th e lin kages betwee n t he key stressors (dri vers) and eac h ec ol ogica l conseque n ce (using a con ceptual model or qu an titative eco lo gical mod e l), and determine the best assessment "endpoints" to use for the risk assessm ent. Possible adverse ecological effects In additio n to the benefi cial effec t of significa ntly reducing cyanobacteria level, four possible adverse ecologi cal e ffects may arise fro m the use of thi s barrier ma terial (Table 1). These b eing: l. Toxicity of the barrier 111aterial. A number of potential ac tive barrier materials may be toxic or release toxic materials wh e n added to a waterbody. Howeve r, the ca lcite ba rri e r m a te ria ls tra il e d a re expected to have very low tox icity, sin ce neither calciu m o r carbo na te ions are know n toxicants.

2. lllcrease turbidity of wa ter col1111111 due to barrier material not f ully settlillg 011t. Th is effect would be to redu ce th e light pe n etration into th e water column , and potentially reduce phytoplankton grow th. O f course, if cyanobacte ria populations were re du ced, this would be a positive effect. H oweve r, if th e main effect was to redu ce the norm al phytoplankto n pop ulatio ns, ch is may have dele terious effects on the o veraU fo od web. 3. A d11erse effect 011 the be11tl1ic algae. T he place m.e nt o f an active barri er may adversely affect the be nthic algae e ith e r by sm oth erin g them or by trapping nutri ents released from the sedim ents before they could be utilised by the algae . 4. A dverse changes to the phytopla11kto11 co1111111111ities, leadi11g to adverse food web effects. T he main purpose o f ac tive barri e rs fo r nutrie nts is to reduce the nutrient flux fro m the sediments and in this way reduce the fr equen cy and severity of cya noba cteria blo o ms. H owever, it is also possible 84

WATER MARCH 2003

Stage 3 : Further trials and detailed ERA

+

Undortako o cologlcal Investigations

Undonako In situ trlals In outrophlc lake

Yes Reconsider Undcrtnke detailed

ERA Barrier not accos;teiblo Yes

Undertake economic

aS'Scssmcrt No

APPL Y BARRIER TECHNOL OG Y

Figure 1c.

that the red uced sediment fl uxes may redu ce all phytoplan kton growth an d red uce the bi o mass to a level that coul d adversely affect the zooplankton grazing on th e algae, and in turn affec t t he fish populatio ns that feed on the zooplankton . Conceptual model Figure 2 is a con ceptual m odel fo r the Lake C arram ar ecosyste m sho wing: (a) sit11atio11 without a barrier - here it is hypoth es ised t hat large amo un ts o f nutrients are released fr om th e sediments under stratified conditions, an d with other nu trient sources from th e catchme nt, t his stimu lates t h e growth o f a large biomass of cyanobacteria. Other p hytopla n kton w ould also be presen t, bu t in reduced concentrations. It is t he more p alatable phytoplankton that are co nsumed by zooplankton, w hich in turn are consumed by fish. Lake C arram ar is relati vely cl ear and supports a bent hic algal commun ity . The presence o f b enthi c algae in th e lake is obvio us, b ut at this stage we have no information on either biomass o r produ ctivity. W e have also hypothesised that th ese b enth ic algae would be a fo od source for bottom- feedin g fis h.

(b) sit11atio11 wit/, a barrier - for this situati on it is hypo th esised that the release of nutrients fro m th e sediments wo uld be significantly re du ced, and that this w o uld result in vety low cyanobacteria levels and possibly also redu ced concen tration s of other phytoplankto n. [f the la tter o ccurs this co ul d resu lt in lower b io mass of zooplankto n and fish. Additionally, w e have assumed the layer of barri er material wo ul d significantly reduce the be nthi c algal distribution primarily by smothering it. Our laboratory e xperim e nts showed that it is p ossible for alga e (and bacteria) to grow o n the top of the calcite layers, bu t we ha ve no da ta ro quantify the level of th is. Risk Analysis The primaty compone nts o f risk, n amely likeli hood (or probability of o ccurrence) and ecological effects, w ere examined fo r eac h of the fo ur issues to evaluate w hat m ight happen to the Lake C a rram a r ec o sys t e m. A se ri es o f hypotheses were developed to describe the respo ns es of our c h osen assess ment e ndpoints w he n calcite acti ve barrie r material is added to th e lake .

Table 3. Risk estim ates to describe likelihood of exposure and extent of effects Ecological issue

Likelihood of Exposure

Ext ent of Effect

Level of Risk

Description

Risk Description Level of Risk

Overall

1 . Potential toxicity

D

Un likely

2

M ino r

L

Low

2. Increased turbidit y in t he water column

D

Unlikely

2

M inor

L

Low

3. Adverse effects on exis t ing bent hic algae

B

Like ly

3

Moderate

H

High

4 . Adverse changes o phytoplankt on ot her h an eyanobaeteria

C

Possible

4

Major

H

High

Description


ENVIRONMENT

In a detailed quantiw ould occur ranged fro m ta ti ve risk assess m e n t , A (almost certain) to E these hypotheses would be (rare), w hi le the ranki ngs tested and refin ed through used to describe the extent the use o f available lite ror severity o f th ese e ffects a t u r e, app r opri a te ranged from 1 (insigni fqu a n titati ve m odels and icant) to 5 (ca tastrophi c) (T able 2) . b e tter c h e mi ca l a nd bi ological informatio n on Risk characterisation Lake Carramar (H are et al., For each o f th e fo ur 20036). H oweve r, at th is e colo g i c al iss u es, w e stage this has no t been co m bin ed th e levels of possible, and w e ha ve risk ass igned to describe u se d a qu a litati ve likelih o od o f the e ffect No Barrier W'llh Barrier assess m e nt ba s ed o n occurring, and the severity e x isting kn ovvledge to if th at effect w as realised describe th e likelihood o f (T able 3) . exposure and extent o f Figure 2. Conceptual model for the Lake Carramar ecosystem, shown This preliminary qualithe possible interactions with the biota both wit h and without an e ffe ct associated with each tati ve risk assessment has active barrier in pl ace. Note that in th is model only th e blue-green stresso r. id e n tifi e d t wo o f th e algal numbers have been reduced with the application of an active W e developed a system possibl e ecological issues as barrier. Howeve r, as discussed in the text, it is also possible that the o f (q u a lit a t i ve) ri s k hi gh risk. Fi rst, was the reduced nutrient release may also result in the reduction of other categories (rankin gs) to possibility that a calcite phytoplankton also. desc ribe th e likelih ood of active barri er w o uld ca use exp osure and extent of a d ve rse e ffec ts to t h e effects expec ted for each tati ve terms. Th e system of rankings was benth ic alga l comm.unity . W e assessed the issu e . This approach was adopted because based on catego ri es presented in USEPA probabil ity that the barrier wou ld interfere exposure and effects data w as limited, and (1998) . T he rankin gs used to describe the with th e benthic commun ity as "likely" co u ld no t be easil y ex pressed in quantilikelih ood th at the ec ologica l effec t and rated th e ecological effe cts ca used by

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this smothering as "moderate", giving a combined high risk rating (Table 3). It could be argu ed that because of the poor knowledge about the importance of the benthic algal community in th is lake, it would be prud ent to adopt a more precautionary approach and rate the ec ological effec ts as "major". However, w hatever rating is adopted, this risk assess ment has pointed clearly to a high (o r extreme) risk that adverse effects would occur on this biological component and flagged the need fo r additional sc ien tific studi es to be undertaken before any barrier mate rial is added to the lake. Issue 4 was also rated as high risk. Th e likelihood that this effect wi ll occur was rated as "possible", but if it did occur the severity of the changes would be "major" on both the zooplankto n and fish com.munities. Agai n , there is considerable uncertainty abou t th is issu e and a great deal of field investigation is needed to clarify the details of the linkages between the reduced nutri ent releases an d the changes to the phytoplankton biomass, and th en between the phytoplankton biomass and the zooplankton and fish comm u nities.

The other issues - toxicity and turbidity in creases - were rated low risk. There is no evide nce that the calcite material is toxic or would con tain any toxic contaminants. Equally , field experience in applying precipitated calcite to waterbodies suggests that this material will settle rapidly and will not increase turbidity, although it is possible that it may reduce turbidity by removing some of the existing turbidity as it settl es. Further field testing would be necessary to determine the potential for the barrier material to be resuspended by wave action, a situation likely to occur in shall ow, exposed lakes.

Stage 3: Further trials and detailed ERA Stage 3 would be undertaken if the outcome from Stage 2 is positive, i.e. the barrier material seemed to work well in reducing sediment nu trient flu xes (and hence in reducing cyanobacterial blooms) and a preliminary risk assessment showed that the risk of adverse ecological effects from the application of the banier was low (see Figure le) . To fully prove th e effectiveness of the barrier material, we recommend that in

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situ trials be undertaken as part of Stage 3. Th ese cou ld co n sist of initial mesocosms ttials fo llowed by full lake tiials if the former are successful. Mesocosm trail s would norn1ally be conducted by isolating part of the lake using a large (e.g. 1-5 111 diam eter) plastic container (swim ming pool without a bottom), adding the barrie r material and mon itoring the resul t over a period of months. With proper pl anning, it should also be possibl e to use the m esoco sm experiment to fo ll ow some of the possible ecological endpoints, information that will be most useful for the fina l detailed ERA. If th e barrier material is proved at the m esocosm level, testing should move to a field tri al with barrier material applied to the fu ll lake system. Obviously, before this occurred there would need to be detailed planning of the method of application and the monitoring program to be pursued. Again both nutrient release and ecological endpoints should be monitored over a period of several months. Finally, chis informatio n could be fed through the ERA process again to determine with more ce rtainty the level of risk that adverse ecological effects might occur with th e use of th is active barrier mate rial. [f the detailed ER..A determined that the risk was low, th is information could be coupled with in fo rm.ation on the effectiveness of the active barrier to reduce nutrient release, the feasib ility of applying the barri er, and the o verall cost-be nefit, to determine whether the project should go ahead. In situations where the ERA showed there was a mod erate to high ecological risk due to the barrier, it would still be possible to re-evaluate the situation and determine whethe r there were particular n~anagement actions that could reduce the particular risk to an acceptable level.

A preliminary ecological risk assessment identified four possible ecological issues that might arise from applying an active barrier to Lake Carramar. Although th e active barrier layer is highly likely to preven t sedi1nent nutri ent release, and thereby reduce the risk from cyanobacterial blooms, th e re is also a mode rate likelihood that th e levels of other phytoplankton will similarly be redu ced. If this latter effe ct does occ ur, there would be major implications for the zooplankton population, w h ich d epends upon th e phytoplankto n for foo d , and for the fish population that in turn depe nds upon the zoop lankton . This poses a high risk to th e overall ecological hea lth of the lake.


ENVIRONMENT

Additionally, it seems very likely that an active barrier layer wou ld adversely affect th e be nthic algae growing o n the bottom sediments of Lake Carramar, and although there is a lack o f in fo rmation o n how serious chis effect would be to this eco syste m , we have still rated it a hig h risk. Th is preliminary E RA has shown that altho ugh addition of a calcite layer would likely reduce sediment nutrient and fr equ enc y of cyanobacterial blooms, there is sti ll a high risk that adverse e ffec ts to the oth er phycoplankton and to the benth ic algae wo uld also occ ur. C learly, th ere is a need for considerably more sitespec ifi c in vestigation to de termin e how the phytoplankton and benth ic algal popu lations would respond to applicati on of su ch an active barrier layer.

Acknowledgements This study was conducted as part of an Inte rn ational R esea rc h A lli ance fo r Managing Co nta mi na te d Sedim ents, funded by the Departm ent of Industry, Sc ie n ce a n d Re so urces u nd er t h e T argeting Research Alliances initiative. BT H thanks th e U niversity of W estern

Australia for awarding him a Senior Gledden FelJowship and co the Centre fo r Wate r R esearch at UWA for providi ng him facilities during which time m uch of th is paper was written. Comments by Dr Justin B rooks of th e Austra lian Water Quality Centre, Ad elaide, improved the paper.

The Authors Professor Barry Hart is Direc tor of the W ate r Studies C e ntre, M o nash U n iver s it y, M e l b ourne (email:barry. hart@sci.m onash.edu .au). Drs Mark O'Donohue and Simon Roberts u nde rtook research on the barriers w hile they were R esearc h Fe ll ows at th e W SC. Mark O'Donohue is c urrently M anager Wate r Q uality at South-E ast Queensland Water. Dr Michael Waters is lecture r in E nvironmental .E ngineering at R M IT Un i versi t y . Elisabeth McWilliam undertook pa rt of th is ERA work dur i n g h e r fin a l yea r of a B ..Enviro nm ental .Engi nee ring degree at R.M IT University . Dr Jeff Taylor is Director of Earth Systems P ty Ltd, w hich has developed t he systems for applying the barrier layers.

References Coleman R (2000). Q11ie1 Lakes b/11c-.~ree11 aL~a/ bloom JHCl'c111io11 .mtdy. Melbourne Water Corpora tio n , March 2000, M elbou rne. D ouglas G B and Coad D M (1996). R er,ie11 1 cif cst11ari11e sedi111e111 rc111ediatio11 1eclt11iq11es. T echnical repo rt 96- 11, CS IRO, Land & Water, Perth. H are BT, Roberts S, James R., O'Do nohue M , Taylor J , Donnert D & Furrer R . (2003a) . Effectiveness of calcite barriers in preventing phosphorus release fro m sedime nts, A11s1. J. Che111. - A11a/. E1111iro11. Clte111. Spm'al lss11e (in press). Hart B T, Lake P S, Webb A & Grace M. (20036). Use of risk assessm ent to assess the ecological impacts of salinity on aquatic systems, A11s1. J. Botatl)' (subm itted) . Jacobs P H and Forstner U (J999) . Concept o f suba q u eo us cappin g of contamin ated sedime nts with active barrier systems (ABS) using natural and modified zeolites. vVater Res. 33: 2083-2087. R yding SO and l<..ast W. ( 1989) . Tl, e Co11trol ef E11rroplticatic>11 cif Lakes m,d R eservoirs. UNESCO, Paris. USE PA ( l 998) . C11ideli11es for Ecological Risk Assess111e111. EPA/630 / R -95/002 F, U.S . Environmental Protectio n Agency, April, 1998 , Washington .

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IMPROVING RIVER MANAGEMENT DURING DROUGHT A Scott, S Lake, P Cottingham, G Jones In recent months Australia has experienced the most w idespread drought on record. Much of the focus has been on agricultural and economic impa cts with less attention paid co the effects on the natural environment. Drought is a natural part of Australia's climatic cycle and natural, low flow (or dry) periods are as important fo r maintaining aquatic biodiversity in healthy rivers as are floods.

What is a drought? Drought can be defined as an unusually lo ng period w ithout rain. More specifica ll y, the Australian Bureau of Meteorology identifies drought under two rainfall deficiency catego ries: â&#x20AC;˘ A severe rainfall deficiency exists in a district when rainfall for three months or more is in the lowest 5 per cent of records for chat area. â&#x20AC;˘ A serious deficiency lies in the next lowest 5 per cent (i. e . lowest 5 per cent to 10 per cent) of historical records for th ree months or longer for that area. The wide range of climatic conditions that exist in Australia means that a long period with little or no rain fa ll might constitute a drought in one region but not in another. For insta nce, many parts of northern Australia receive little or no rainfall for 3-4 months in the n1iddle of each year, but this is not a drought since it is a predictable event that occurs every

year. However, in other regions that have high rainfall all year round, a period of 3-4 months without rain will cause a severe dro ught.

Droughts and ecosystem disturbance Extrem e events, such as droughts and floods, play an important role in the fun ctioning of our river systems and in the maintenance of biodiversity . A drought can be considered as an ecosystem disturbance (i.e. reduced water availability) to which plants and ani mals respond. T he response of biota can take two forms: resista11ce is the capacity of the biota to withstand the drought, while resilience is the capacity of biota to recover fron, the drought. In some regions, relatively predi ctabl e dry seasons occur each year, and freshwater biota have evolved adaptations, such as life history schedu ling, or the use of refuges such as deep waterholes, to survive them. In general, the response of biota to predictable dry seasons is characterised by a high resistance and a strong resilience. Droughts, ho wever , are less predictable and this m akes it more difficult for organisms to develop adaptations and strategies for survival. The response of b io ta to droughts is characterised by a low to m oderate resistance and a variable resilience, making recovery

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more difficult or requiring m ore time than fo r seaso nal dry periods . T he pred ictable nature of seasonal even ts has tended co make them easier to include in ecological studies. Less is known about droughts and much of o ur knowledge has been derived fro m opportunistic studies that were initially set up for other purposes.

What happens to river systems as they dry? A drought is characterized by a sequential decline in rainfall , surfa ce runoff, soil moisture, groundwater inte raction, and ultimately discharge, for naturally flowing ri vers. As the drought progresses, floodplain and wetland areas dry, and rivers b ecome confi ned to their low-flow channe ls. Th ese dynamic processes play a key role in the long-term maintena nce of fr eshwater biodiversity. Although there is a widespread reduction in aquatic habitat, there is a corresponding increase in the area of semi-aquatic and terrestrial habitat. For instance, as the water recedes, new plants germinate in the exposed mud and waterbirds such as ibis and spoonbills feed in the shallow pools and mudflats . As river flow ceases, fish and other aquatic o rganisms seek refuge in the remaining pools, where the interaction of predatio n and competition can markedly


ENVIRONMENT

alte r co mmunity compositi o n . M a ny terrestrial animals also rely heavily o n these rema ining waterholes for the ir drinking wate r. Any macroinvercebrates or fish chat beco m e stranded in dri ed up habitats, provi de an abundant fo o d so urce fo r te rres trial predators and scavengers, such as birds and ants. As waterholes decrease in size , the deat h and decomposition o f aq uatic plants and animals re leases nut ri ents su ch as n itrogen and ph ospho rus into t h e rema ining wate r. E vapo ration slo wly con centrates these nutrients even further. H igh nutri ent le vels can result in de nse growths o f algae, particularly during summ er. Th ese are grazed by mac roin verce brates, w hic h in cum are eaten by fish . T he algae may create large diurn al changes in O>-' )'gen con ce ntration , and if se ve re algal bl ooms occ ur, th e low overnight O>-' )'gen le vels mi ght ultimately threa ten aquatic bi o ta, suc h as fish. Evapo rati o n also causes an in crease in salinity, and th is affects salt-se nsitive plan ts and animals. Th e intrusio n o f saline groundwater can also increase as the water leve l i n th e ri ve r c hann e l drop s . Gro undwater intrusion can cause stratificati o n in po ols, leading co further dete rio ration of water quality and a higher c hance of algal bl o oms.

Resistance mechanisms for drought Organisms resist d rought using a range o f physiological, behavioura l and life stage responses. Fo r instan ce: • Fish move dow nstream o r ret reat co isolate d p ools as head w ate rs d ry. • Pla nts reduce evapotransp iration losses fro m l eaves and sec seed . • Y a b bies, so m e frog species, and insects su c h as w a te r b ee tl es , surv ive b y

burrowing deep into moist sedim e nts. These animals can remain safely buried for many mont hs o r even yea rs. • Turtl es migrate ove rland co find n ew wa te rh oles, w h ile o ch e r spec ies ca n hibern ate fo r at lease 3 m o nths without wa ter. • Z oopl ankcon, some be nth ic in vertebra ces, al gae an d ba c te ria produ c e d esicca ted, d rought resistant spores. • W ate rbirds £l y m a ny hundreds o f kil o m e tres to find m o re permane nt water, such as coastal es tu aries. In spite of th ese resistance mechanisms, some po pu lati o ns m ay su ffer large losses during a drou ght and cake many yea rs co recover. H o wever, the li fe cycles of o th er species a re highly depe ndent o n an extend ed d rying phase, and th e ir longterm survi val is de pendent o n a cycle o f £l o ods and droughts. Also, som e introdu ced pests have poo rly d eve lo p ed resistan ce m echanism s for dro ug ht, and th is can pro vide a competitive ad va ntage to dro ug ht tole rant nati ve species.

What happens when the drought breaks? Australia's freshwater £lora and fauna are generall y w ell adapted co patterns o f fl ood and drou g ht and ha ve developed m echanisms fo r recove ry . H o wever, the race o f recove ry ca n va ry considerably , being influ enced by successio n patterns and w heth e r o r not any species that have been lose can be restored. R ecolo ni satio n b y fa u na fro m drou g h t re fu ges is impo rtant in chis recove ry. A proble m arises if refuges such as pe rmanent wate rholes o r billabo ngs have bee n e liminated by river regulation, wate r extra ctio n o r fa rm de velo pment. An y loss o f previ o usly abundant species can result in maj o r changes to community structure and a lag 111 reco very.

Wh en the droug ht breaks, the initial flush o f wate r do w nstrea m is likely co bring large qu antities o f sedim ent and orga nic m atter that has steadily accumulated in the catchment during the d rought. The organic m atter and dissol ved nutrients provide an abundant fo od supply and chis can result in a mass hatching of invertebrates. This in turn provides fo od for high er o rga nisms such as insects and fish . Hig hly m o bile species, such as w ate rbirds, qui c kly m ove in from surrounding region s co take ad va ntage of these ne w food suppl ies. The community that existed before the droug ht may no t fu lly re-appear until th e re has been a co mpl e te progression fr o m earl y coloni zers throug h to species w ith longer life cycles. So m e species, such as nati ve fish may take m any yea rs to full y reco ve r bu t, o ver d ecadal scales, th e re is little evide nce that fish populations are affected by dro ught in health y ri ver syste ms.

The impacts of water management during drought Many rivers have bee n degraded by loss o f habitat, changes in fl o w regim e and poo r w ate r quality. T hese impacts can exacerbate th e stresses already experienced by aquacic fa una and flora d uring droug ht pe riods. W here ecosystems are already deg raded, the ability to survive may be dam aged , and the speed of recovery inh ibited. For instance, hi gh erosion races can cause a massive inflow o f sand and silt into the main river chann el , and this ca n g rea tly reduce th e availability of dee p w ate rholes as dro ught re fu ges. Similarly, th e e x trac ti o n o f water from th e rema inin g wa te rholes along a ri ve r c h a n nel , can g re atl y dimin ish th e resilie nce o f the river's biota to dro ught.

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A hi gh demand for water during drought often results in a large drawdown of lakes and reservoirs. As the nutrientrich bottom waters move closer to the surface, the increased availability of light can resul t in higher rates of algal growth, and in some instances, the formation of bl ue-green algal bloo ms. During drought periods, low flows through weir pools can result in stratification of the water, and this also in creases the ch ance of algal blooms . The inflow of pollu ted water from point sources, with little subsequen t dil uti o n, can also contribute to poor water quality conditions in rivers during low flow conditions. Problems such as eu trophi cation, the formati on of algal blooms and the development of low oxygen con ditions, all increase the stress already experienced by river biota duri ng drought. For example, the low oxygen conditions that result from the growth, death and deco1nposition of large algal blooms in weir pools or reservoirs, can result in severe fish kills . Along regulated rivers , the floodplain vegetation is already stressed by the reduced frequency of floo d in undation . During a drought this stress is heightened

by the extended period of d1ying, and also from. elevated concentrations of groundwater salinity. Each of these issues needs to be carefully addressed by river man agers to ensu re that the impacts of drought on regulated rivers do not result in permanent loss of biod iversi ty o r a long-term reduction in river health. In severely degraded rivers and wetlands, a prolonged drough t may be 'the straw that breaks the camel's back' fo r some of the sensitive or threatened species.

Better management of rivers during drought The way we manage the land and water within a catchment, both during and following a drought, is of criti cal importance to the health of our rivers. In particu lar, in-stream and floodplain refuges, and the organisms they support, need to be protected. Some management actions that can be taken to protect aquatic communities are disc ussed below. Large dams greatly alter the natural flow regime of rivers. If dams are emptied during drought, it can take months or

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years until th ey refill and spill again. In such cases, the section of river immediately downstrean1 of th e dam may experience a greatly extended drought period. Periodic flow releases, including base flows and pulses, can help the downstream aquatic communities survive and recover from these droughts. T h ese releases might also reduce the risk of stratificati on in downstream pools, wh ich in turn decreases the chance of an algal bloom. It mi ght also reduce the risk of deoxygenation or poor water quality in stagnant pools, which can pose a risk to the native fish populations. Although some may consider th ese flow releases as a waste of precious water d uring the drought, it is a small and very so und investment in sustaining healthy rivers. During drought conditions, native fish tend to congregate in the remaining deep waterholes along a river channel and are easy targets for fishing. If a large number of the remaining fish are caught, their rate o f recovery after the drought will be greatly inhibited. This is also tru e in large water sto rages, whe re the remaining fish might have to congregate in only 5 or 10% of the maximu m storage volume.

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90

WATER MARCH 2003

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During these times, it would be wise to introduce restric tions on fishin g, to ensure that sufficient adult fish survive th e drou ght for future breeding. When river flow ceases and the channel bed starts to dty up , the remaining waterholes become refuges fo r birds, fish, amphibians and in vertebrates (such as yabbies and insects). It is critical that these waterholes are not pumped dry when providing water for livestock. A lternative sources of water shou ld be considered w he re possible. During droughts, livestock tend to co ngregate along riverbanks and around the remai n ing wa t er h o les. Overgrazing, trampling and high levels of du ng ca n add severely to th e stress that these habitats are already experienci ng. Stock should be excluded from ripari an lands and alternative watering points should be provided away from the river. Managers of drinking water supplies also need to be aware that droughtbreaking storm events are likely to bring signifi cant 'dirty water' into rivers. Storm run-off will pick up high concentrations of fine sediment, nutrients and pathogens fro m. the dry soil su rface, especially during the 'fi rst flush' of h eavy rains. In south-eastern NSW, northern Victoria and the ACT, the drought of 2002/03 resu l t e d in w idespread forest fire s throughout the entire Snowy Moun tains region. T he loss of protective vegetation cover grea tl y increased th e risk of p·oor wate r quality duting the first rainfall events after the fires, leading to high loads of sedi ment and as h b e in g was h e d downstream. In the ACT, w here 90% of

the Cotter River water supply catchment, was burnt, floating booms and curtains were installed at strategic points in the dams and reservoirs to stra in out ash and other debris that could otherwise enter the water suppl y . If water quality is affected by such events, it may be prudent to bypass the first flush of dirty water or re vert to alternative wate r suppli es . Th e impa ct of nutrie nts so lubilised in the ash may be of conseq uence.

Increasing our knowledge of droughts T o develop best practices for river management du ring drough t, we need a comprehensive understanding of how freshwater aquatic systems respond to reduced (or no) flow. H owever, our knowledge is still very limited, and the Cooperative Research Centre (CRC) fo r Freshwater Ecology is currently trying to address th is shortfall. The 'Dryland River Refugia' project is investigating rivers in the no rthern regions of the Murray-Darling Basin and in the Lake Eyre Basi n w here episodic floods are o fte n fo llowed by extended periods of drought. For mu ch of the time these rivers exist as a network of tu rbid waterholes along ephemeral chan nels. This environm ent provides an ideal opportuniry to determ ine the importance of waterholes as re fuges for aquatic organisms. The project is investigati ng the relationsh ip between bi od iversiry and the physical attributes of individual waterholes, and how populatio ns are connected in space and time. lt is also identifying the

biophysical processes that sustain biodiversity and ecosystem health within these aquatic ecosystems. The 'Granite C ree ks ' project in northern V ic toria , is investigating how aquatic organisms disperse, and how fa r they can move. Th is provides valuable information on the ability of plants and animals to recolon ise sites after a disturbance such as drough t. The 'Cotte r R iver' projec t, in th e ACT, is investigating how to maxim ize the ecological be nefi ts of en vironmental flow rel eases below two large water sto rages . T hese releases sho uld help mainta in sui table hab itat for native fish species, particularly during extended droughts when the impacts of the dams would otherwise result in unnaturally long pe ri ods of little or no flow. Th ese, and other research projects by the CRC for Freshwater Ecology, will help us to increase our knowledge base, and shou ld lead to better manageme nt of rivers and their catchments during periods of drought.

The Authors Anthony Scott is a Kn owledge Broker at the CR C for Fres hwater Ecology in Canberra; Professor Sam Lake is the Chief Ecologist at the CRC for Freshwater Ecology and is based at M onas h Uni versiry; Peter Cottingham is a Knowl edge Broker at the CR.C for Freshwater Ecology in Melbourne; and Professor Gary Jones is Chief Executive of the CRC fo r Freshwater Ecology in Canberra.

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91


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WASTEWATER

MONITORING BIOSOLIDS QUALITY: A STATISTICAL PERSPECTIVE W L Paul, NS Barnett Introduction Th e Victor i a n E P A Draft Environmental Guid elines for Biosolids Management (2001) aims to provide a framework for achieving the safe and sustai nabl e u se of biosolids . This framework includes standards for contaminant and pathogen levels and guidance on the statistical design of a biosolids monitoring program to ensu re there is only a 5% probabili ty (or risk) of in correctly allocating the biosolids to a hi ghe r quality grade. In effect, the EPA is acting as a proxy end- user, or consun1e r, of biosolids produ cts: they have set the limiting quality levels fo r various end-uses and se t the maxi111u111 acceptable risk of 111isclassification ofbiosolids product (i.e., the type II error risk, w hich is 5%) . Th e G u idelines, however , do not address the issues for processors and generators tha t need to be considered in the design of a monitoring progra111 to ensure that it sui ts the interests of both produ cers and consum ers alike. In this paper we discuss som e of the statistical aspects of the Victorian EPA Biosolids G ui delines and identify the key issues, not covered by these gu id elines, which need to be considered by generat ors and pro cesso rs in m onitoring biosolids status. These issues include the need to define the target qua lity level and the producer's risk (i. e., type I error risk), the sampling design that w ill give the information needed for the least cost, the potential for co mpounding risks when multiple contaminants are assessed for compliance, and the need for coop eration between generators and processors to e nsure that the interests of both are 111et in the monitorin g-program design. These issues are left to be the responsibility of the generators and processors, and they need to be addressed in any agreem ents or Environm ent [mprovement Pl ans because they require input fro 111 both producers an d consumers. T hey are important issues to consider because they wi ll minimise the costs of sampling and testing, with respec t to agreed d ec ision error risks, and thereby improve th e viab ility o f the industry.

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WATER MARCH 2003

Acceptance Sampling for Quality Monitoring The fu ndamentals of a compliance monitoring program were described in a previous Water article by Paul and D iamond (2001). Essentially, a compliance monitoring program is the sam e as an acrepta11ce sa111pli11g procedure, frequently used for quality monitoring in the manufacturin g industry. Two of the 111ost infl uential too ls of manufacturing manage111e nt, the co ntro l chart (developed by Walter Shewhart in the l 920's) and acceptance sa111pli ng, e111anated from work done at Bell Labs in North America. T hi s latter concept was devised by Dodge an d R o111ig around 1930. They developed sch e mes whereby large quantities of product, for w hi ch exhaustive testing was proh ibi tive, could be assessed on the basis of tested samples. W hen ever a dec ision is made about a lot (e.g., a sto ckpile of biosolids) on the basis of a sample, whether a 111anu fuc turin g process or not, there is a risk of being wrong and this is unavoidable. We seek, however, to proceed in a 111anner that keeps the risk low subject to cost constraints. If we consider the impact of this risk on two parties that are most affected by a wrong decision, then we can see this risk in one of two w ays depending on which of the two parti es' perspective we take. In e ffe c t , in relation to biosolids processing, th e processo r is a 'producer' and, in setting the rules, the EPA is behavi n g like a 'c ustome r'. In a dichotomous si tuation suc h as this, both parties cany a risk, one, the producer's risk and the other, the consumer's risk, but they are different. G iven the type of classification that is in the Draft E nvironmental Guideli nes for Biosolids Management (2001), the processor's risk (produ cer) is in proceeding in a m anner intended to prod u ce a b io so lid s produ c t for unrestricted use, for example, only to fi nd that the lot doesn't com ply with the relevan t limits on the basis of samples (i.e., owing to rand om sa m pling e rror alone) . The consequence of this is that the material has to be re-wo rked (and retested) or re-classified to a lower grade. The EPA's risk (consumer), howeve r, is in deeming a lot of bioso lids from th e

processo r to be su itable for unrestricted use when, in fact, it should be classified as 'restricted uses' only, and this has potential consequences for public and environmental health. [f we quantify these risks in terms of probabilities then th e two have an inverse rela tionship w ith one another - as one decreases the other increases (for a give n sa mpl e size). A holistic approach to reconci ling thi s conundrum must consider any trade offs from both the perspective of the producer (processor) and the consumer (EPA). In many man ufacturing environm e nts the concept of produ cer and consumer is a gross simplification si nce, frequently, 'producer' and 'consumer' are m erely two adjacent positions in a manufacturing chain. In this particular instance, the processor, whilst be ing a 'producer' from the perspective of the E PA is, in fact, a 'consumer' for th e generator ofbiosolids, that is, the treatmen t plant. In fact the processor could be described as th e 'meat in the sandwich ' . Acknowl edging this should lead to a more collaborative approach between all three parties to establish ing reasonable risks.

Background on VIC EPA Biosolids Management Guidelines Brie fly , the Guide lines stipulate that a sample (say 5 ( 1 kg units) should be taken from a stockpile of biosolids and an alysed fo r a variety of contaminants, and then the Biosolids Co ntaminant Concentration (BCC) sh ould be ca lculated from the sample me an and va riance o f each contam inant according to the equation,

Y.Jn

ace= x + to.9s11

(1)

w here X is the mean contamin ant concen tration for the sample; ( 95;1 is the value of Student's t statistic fo r a one-sided confide nc e interva l an d degrees of fre ed om df = 11- l; S is the standard deviation of the sample ; and n is the sa mple size . It should be noted that the t-coefficient in the equation given in th e Guidelines has not been subscri pted with a probability, and nor has it bee n properly defined in th e text . This value of t actually corre-


ASTEWATER

VITACHE sponds to the power 41/ic test and not the confidence level or the type I error as alluded to in the Guidelines. The BCC is then compared to the limits in the Guidelines (i.e., Grade C1 and C2 limits), and the biosolids art• determined to be compliant with a particular chemical grade if the BCC is kss than the relevant limit. In effect, the EPA wants to know whether the calculated sample mean X is consistent (with 95r% "confidence") with coming from a population that has a mean equal to the CI or C2 limit. If it is 1wt consistent with the Cl limit, for example, then the stockpile is classified as Grade C 1 13iosolids. This rnay sound odd, bur that is because it amounts to testing the alternate hypothesis rather than the usual practice of testing the null hypothesis. [Those readers who don't need the mathematical detail can skip to the next section.! For the statistically indim.•d, the hypotheses of interest when deciding between a C 1 and C2 classification (for example) arc,

H0 : µ < L H,: µ;;, L

(Grade C1) (Grade C2)

where L is the Cl limit. The probability of classifying a lot as Grade C2 when that lot is truly of Grade C2 is the po111cr r.f the fl'.l'f; that is, the power of the test is the probability of rejecting H 0 when HA is true. The power of the test is denoted by 1-~, where ~ is the type II error risk (or consumer's risk); taking the threshold value µ=L it can be expressed mathematically as,

1-[3=P(X;;,x,/µ=L)

=P(t;;,:;/n) = P(t;;,-t1_P) Given that I - ~ has been specified to be 95% by the EPA, the critical value for the sample mean Xe (i.e., the point on the continuum that delineates compliance and noncompliance) can be determined from,

-t

=

.,s11

<=>

x,-L sf .fr,

x, = L - 19511 Y.Jn

So, we will correctly classify a lot as Grade C2 with 95% "confidence" (or power) when our sample mean is greater than or equal to this critical value:

X" x, = L- 195/1

Y.Jn

Through some simple rearrangement of this equation, it can be seen that a lot will be correctly classified as Grade C2 with a minimum of 95% power when the BCC is greater than or equal to the C 1 limit:

L,;; ace= x + t_,, 11

Y.Jn

If the BCCis less than the Cl limit then the lot will be incorrectly classified as Grade Cl with a maximum type II error risk of 5%. This equation for the BCC is the same as Equation , which is the equation given in the EPA's guidelines (subject to the alteration mentioned earlier). Therefore, the limits in the Guidelines are to be interpreted as the alternate hypothesis or limiting quality level, and the EPA has specified the po,ver (and, therefore, type II error risk). It is now up to the processor to determine the null hypothesis (i.e., their target quality) and the type I error risk (i.e .. the risk of rejecting a compliant stockpile) in order co begin designing a monitoring program that meets their needs as well as those of the EPA. /It should be noted that in the absence of the decision criterion adopted in the Guidelines, which is based on Equation and the Cl or C2 limits, there are three other interpretations of the limits, which would considerably alter the design of the monitoring program. The choice of interpretation is not an arbitrary one; it depends on how the limits were derived. It's our belief that the limits were simply meant to be concentrations that represent the maximum acceptable risk to public and environmental health that have been determined through a process of balancing risk and social/economic factors, without reference to simple (null or alternate) hypotheses. This is quite difi(•rent to the interpretation in the Guidelines, and this issue requires debate to ensure a consistent interpretation of the Victorian and the national guidelines (NWQMS Draft Guidelines for Sewerage Systems Biosolids Management, 2002).!

Monitoring Program Design for Biosolids Processors When a processor receives biosolids of a specified quality from a generator, he/she then decides upon the dilution or blend (e.g., with sawdust) required to make a biosolids produce that has a specific end-use. Processors need to define the target quality level for their various products, whether they arc intended for domestic use, agricultural use, or fill for landscaping or land restoration. They also need to define the maximum acceptable risk of rejecting a compliant product. Their objective should be to find the combination of target quality and error risk that minimises the combined costs associated with sampling and testing, blending, and rejecting a

good lot. Take copper as an example, with a Cl limit of 100 mg/kg. Assume the population standard deviation is known to be 20 mg/kg. The Guidelines specify the limiting quality level (alternate hypothesis, HA) to be 100 mg/kg, with a type II error risk of 5%. The processor initially decides on a target quality level (null hypothesis) of 90 mg/kg. The decision rule for deciding

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whethe r th e bi osolids stoc kpil e is compliant will be based on a critical sample mean of 95 mg/kg. The sample size requi red to achieve the Guideline's obj ectives can be calculated from,

X- µ

Z as =

Xe - L

a-/.Jn = a-/.Jn ~ n =

2

( 1 Z 050"

Xe - L

where z_05 is the z-score, from a table of the standard normal distrib ution, that corresponds to a (type II error) probability of 0.05 or 5%; Xe is the criti cal sample mean w hi ch is the point on the continuum that determines compliance or non-compliance; L is the Cl limit; CJ is the population sta ndard deviation; and n is the sample size. T herefore, in this example,

n =(-1.645x20)2 95 - 100

= 43.3 "" 44

Our decision rule is now complete; it consists of a critical sample mean of 95 mg/kg an d a sample size of 44. T he operating characteristic curve for th is rule is shown in Figure 1. From this curve, it can be seen that this decision rule gives the processor a 95% chance of comphance if the target quality level is achieved (H 0) and a 5% chance of incorrectly rejecting a good lot (i.e., a type I error risk ofa=5%). If chis type I error risk is considered too high (owing to the expected cost associated with rejecting a good lot), then the sample size could be increased. If the sampling effort is considered too expensive (44 samples) then a target quality level less than 90 mg/kg might be the answer; though, a balance would have to be achieved between the reduced cost of samp ling and testing and the increased cost of a higher blend ratio. Any number of scenarios can be explored using OC curves to get the right target quality level and type I error risk.

Monitoring Program Design for Biosolids Generators For the biosol ids generators, who supply processors wi th biosolids of a specified quality, the problem is m ore one of statistical estimation (i .e., mean and confidence interval) than compliance assessment. T he task for the generators is to determine the quality of their biosoli ds with an agreed level of precision. For example, say the generator has pilot data that indicate the mean copper concentration to be 450 mg/kg, w ith a standard deviation of 25 mg/kg. With a mean of 450 mg/kg, the processor would have to blend th e biosolids wi th

94

WATER MARCH 2003

4 parts of sawdust (i.e., 1 :5 dilution) to achieve his/her target quality level of 90 mg/kg. T he processor would need to be confident (say 95% confident) that when the material is blended the population mean copper concen tration will be within about ±2 mg/kg of the target of 90 mg/kg, so that his/ her probability of compliance isn't affected greatly. The figure of ±2 mg/kg is a fairly subjective one . It was obtained front Figure 1, by noting that the probabili ty of compliance wou ld not alter greatly if the true mean Cu concentration was between 88-92 mg/kg. T he generator, therefore, needs to ensure the mean copper concentration in his/her biosolids is known w ith 95% confidence to be within approx imately ±2% (i. e., 2/90 "" 0 .02 or 2%). While a simplifying assumption is made that the blending process doesn't change the relative standard deviation, this approach provides a sound basis for the generator to choose a sample size for his/her own monitoring program. T he processor has effectively set the maximum error (E) to be 2% of 450 mg/kg (i.e., 9 mg/kg) for the generator's estimate of the mean contamina nt concentration. From the formula for a confidence interval , the sample size required to achieve this maximum error can be calculated: O"

E = za,2 . .Jn

=

1.96x25

.Jn

=9 mg/kg :. n = 29.6"" 30 This is a simplified exam ple because we've assumed the population standard deviation to be known. In practice, it is not known, and so it has to b e estimated from pilot data. Under such circumstances, the t-statistic is used in place of the Z-statistic, and an iterative approach is used to find the required sample size. The generator and processor need to understand each other's requirements and constra ints in order to design sound and practical monitoring programs.

General Considerations in the Design of a Monitoring Program Generators and processo rs also need co consider the d esign o f their sampling plans to ensure the most efficient plan is adopted; that is, the one that gives the info rmation desired for the minimum cost . Another consideration is the effect on decision error risks when multipl e

contamina nt s are compliance.

assessed

for

Simple-random or stratified-random sampling R..andom sampling is empl oyed to ensu re that the estin1ate of the mean contaminant concentration is unbiased (as well as provide a valid estim.ate of the sampling error and satisfy the assumptions underpinning the statistical tests) . The most straightforward form of random sampling is sil/lple ra11.do111 sa111pli11g, but if th e material to be sa mpled is known or thought to have distinct strata (i.e., patches with qu ite different contaminant levels) then stratified random sampling can give the same precision for a reduced samp ling (and testing) effort. In either case, pilot data are needed to check assumptions and to optimise the sampling plan. A problem arises w hen we consider that only part of a stockpile might go to a particular custom.er. If there are distinct strata within the population (i .e ., if there are ' hot spots'), the generator's estimate of the m ean concentration may not represent the one or two truckloads that are delivered to the processor. There are two possible solutions to this problem: 1. Segregate the strata and take additional samples from each to achieve the agreed sample size (and confidence interval width). The different strata would then have separate certified quality levels. 2. Homogenise the stockpile by physically m ixing with a front-end loader.

The choice of solution depends on their relative costs . Single or double sampling A single sampling plan involves taking one sampl e of n cores from a stockpile of b iosolids and th en determ in in g co mpliance by comparing the sample m ean to the critical sample n1.ean in the decision rule. T he example given earl ier, in Monitoring Program Design for Biosolids P rocessors, uses single sampling. Double sampling, on the other hand, involves: 1. T aking a sample of size n (which is smaller than the sample size that would be used for single samplin g). 2. If the sample mean is less than a (the first critical sample mea n), the stockpile is accepted to be compliant; if it is greater than b (the second critical sample mean), the stockpile is rejected as non compliant. 3. If the sample mean is between a and b, the compliance status is uncertain and a second sample of size m is taken. If the mean of the results from the fi rst and


WASTEWATER

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Ho

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100

105

110

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80 90

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100 120

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70 60

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Figure 1 . OC Curve for a decision rule with a critica l sample mean of 95 mg/ kg and sample size of 44.

secon d sampl es combined is less th an a , then th e stockpi le is accepted as compliant; if the mean is greater than a, the stockpile is rej ec ted .

85

90

As an example o f a do ub le sampling plan , recall th e copper example di scussed in Monicoring Program Design fo r Bioso lids Processors. With a do uble sa mpling plan, th e probability of compliance is give n by, P(Compliance) = P (Fi rst sample co mpliant)

u P(First sample uncertain n Comb ined sample compliant)

= P ( X1 :,; a) + P ( a < X1 :,; b, X1 + x2 :,; 2a) b

1) •

f x, ( x1 ) dx

A

[assuming b < 2a]

whe re X1 is the m ean o f th e first samp le and of the second sa mple,

95

100

105

110

115

::,

g 0

60

}

70 i» ::, 80 --- 90

0

"'

~

100 120

Figure 2. OC curves for a double sampling plan.

Expected sample size = 30 + P (First sample uncertain) x 30 = 30 + P (a <

Double sa mplin g ca n give the same decisio n error risks as a single samplin g plan , but th e sa mple size and cost ca n be significa ntly reduced .

f Fx, ( 2a - x

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T

80

50

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Population mean (Cu, mgA<g)

Population mean (Cu, mgA<g)

= P ( X1 :,; a) +

0

-

80

.,C: a

-

-----1-----~-' ---- rintt&mplt -----1-dOIJl:jesam~

90

10 20

HA

·-..

100

0

X2

is the mean

fx, is the density fun ction fo r the m ea n o f the first sample, and Fx, is the cumulati ve distribution fun ction for the m ean of th e second sample. For the copper example, if w e use a sa mple size of 30 (i.e., n = m = 30) and critical sampl e means o f 94 mg/ kg (a) and 96 mg/ kg (b), the OC curves for the first sample and the double sa mple will be as show n in Figure 2. [Other values for n, m, a and b could be explo red to see what effect they have on the O C curve.] The things to note about these OC curves are: • The type II error risk is maintained at about 5% for both th e fi rst sa mple and the double sample; • The type I error risk is reduced fro m 17% to 7% by resampling; • The OC curve for the double sa mple is almost identical to the OC curve fo r the single sa mpling plan shown in Figure 1. If the processor consiscencly achieves a product that is on target with a copper con centration of 90 m g/kg, then the expected sampl e size for th e double sampling plan is,

X, :5 b) x 30

= 30 + P (94 <

X,:,; 96) x 30

= 30 + 10%x30 = 33

That is, in th e lo ng run , th e ave rage sa mple size will be 33 . The co rrespo nding sin gle sampling plan required a sa mple size of 44. On average, then, th e sa mpling and testing effort could be reduced by 25% by impl ementing do uble sa mpli ng. Composite sampling

If the va riance of the sample mean were sho wn to be consisten t after mo nitoring several stockpil es of biosolids and there were no distin ct strata w ith in th e stockpiles, it wo uld be reasonable to begin co mposite sampling (i.e., co mbining all laborato ry sa mples into o ne), th ereby significantly redu cing th e cost of testing, again. This wo uld need co be approved by the EPA and occasional testing of all cores wo uld n eed to be carri ed out to chec k that the process has not changed (or, alternatively, regularly mo nitoring the raw sewage to identify trends in BODS and biosoli ds contaminancs) . Proportion of a stockpile to be sampled The Victo rian guidelines recommend that a minimum of one sam ple sho uld be taken fo r every 100 to nnes o f biosolids, but this recommendation is a little misleading. It ca n be sho wn that in a large po pulation (i.e., stockpile) chat the standard error (and , therefore , th e width o f the confiden ce interval) depends mainly on che size of the sample (n) and only to a minor extent o n the fraction of th e population chat is sampl ed. In practical applicatio ns, it can be assum.ed that the standard error is unaffected by the fractio n of th e popu lation sampled when that fra ction is less than 10% (Snedecor & C ochran, 1971) - which is certainly the case in biosolids monitoring because usually only a few kilograms are taken for every 100 tonnes. The impl ications of this are chat, for a given confidence incerval width , the same sample size is required for 100, 000 tonnes of biosolids as ic is fo r 100 tonn es of biosolids. This, of course , assumes that there are no distinct strata w ithin th e population; this is an issue that wo uld need investigation. If th e material is reasonably homo gen ous, however, it means that the cost of sampling and testing co uld be spread across a m uch larger Joe of biosolids, thus signifi cantly lowering che co st of sampling and testing p er kilogram o f biosolids. WATER MARC H 2003

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Compounding Risks with Multiple Contaminants When compliance is being assessed for multiple contaminants th e probability of compliance can drop dramatically and this should be acco unted for by making an adjustment to the sign ificance level used . For example , if there are te n contaminants and a signi6cance level (type I error risk) o f 5% is used fo r each comparison , then the probability of compliance when the target quality level is actually being ach ieved will be (assum ing the contaminants are statisticall y indepe nde nt),

P (Com pliance) =

(1 - a)1°

= (1 - 0.05 )1° = 0. 6 (60% ) So, w hile the probability of compliance is 95% for a single contaminant, it is only 60% for ten contam inants. To ensure an overall probability of compliance of 95% the sign ifi ca nce level for a single comparison should be divided by the number of contaminants. This is called a Bon ferroni adjustment . In the example above , if we use a significance level of for each contaminant, then the

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overall probability of com.pliance wi ll be 95. 1%. Ir's worth noting that the sam e reasoning applies to the type II error risk (consum er's risk or EPAs risk) .

Conclusion T here are a nu mber of issues that need to be consid ered in the des ign of a biosolids monitoring program to ensure the ne eds of generators, pro cessors and consumers (EPA) are met. T he Victo rian E PA Draft Environ men tal Gu idelines for Biosolids M anagem ent goes part the way to addressing the statistical co nsiderations for monitoring biosolids quality, but there are othe r important issues for gen erators and processors that need to be well th ought-out. T hese issues include defi ning the processor's target quality level and maximum acceptable risk of rejectin g a good lot, designing an efficient sampling plan to minimise costs, adjusting signifi cance levels when multipl e contarn.inants are being assessed, and the need for cooperation b etwe en generato rs an d processors.

References N ational R.esourcc Managcrnenc Ministerial Council 2002, N WQM S Draft G11ideli11esfor

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Sewerage Syste111,· Biosolids Ma1iagc111e11t, AFFA, Canberra. Paul W and Diamond N T (200 I 0 "Designing a Monitoring Program for Environmental R..egu lation: Part I - T h e Operating C haracterist ic C urve", WATER ,. 28, N o. 7, p.p. 50-54 . Snedecor G W and Coch ran W G (1971) Statistiwl 1\!Iethods 6th cdn, The Iowa State Uni versity Press, USA. Victorian Environment Protectio n Authority (2001) Dr~fi E1111iro11111e11MI G11ideli11es for Biosolids .\ ln11nge111e11t, E PA, Victoria.

Authors Dr Warren Paul is a lecturer in s t at is ti cs in t h e Dep art m e n t of Environmental M anage m.ent & Ecology, La Trobe Un iversity (A lbury- Wodonga) . Warren has a backgroun d in environn1.ental statisti cs, parti c ularly in the area of process and quality control in the wastewater indu stry. Assoc. Prof. Neil Barnett is a senio r aca dem ic at Victoria Uni ve r s it y , i n the Sc ho o l of Communi cations and Info rmatics, w hich he fo rme rly headed . H e has a history of qual ity man ageme nt and sta tistical co nsulting, main ly in the continuous pro cess indu st r i es . Ema il : w .paul@ aw.latrobe.edu.au.

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PUBLIC AND PRIVATE OPTIONS IN AUSTRALIAN WATER MANAGEMENT Since the early 199O's, tire A ustralia11 water ind11stry has e111braced a wide m1·1ge of options for engaging tir e private sector, short of act11al pri1l(lfisation. A11stmlia 's State-based admi11istmtio11 of tire 11tilities sector has pro111oted a 111ide rm1ge of alter11a1ives to tire previo11sly prevaili11g p11blic sector prowre111e11t practices. Early comersto11e co11tmcts pro111oted tire develop1n e11t of a competent prii1ate sector that 110w provides a wide range qf services and possesses the capabilityfor an eve11 broader scope of i1,Jmstruct11re and operations so11rcing by tire public sector water 11tilities. Considerable scope for i11stiiutio11al refor111 re111ains, particularly in regards to 111ore ejficien.t b11sinesses with a11 i11creased Jaws 011 c11s/0111er and b11si11ess 011tcomes, rnggesti11g additio11al opport1111ities fo r public private partnerships. Co1111e11tio11al

P J Perkins pri11atisatio11 of 1vater services offers little scope. Ho111e11er, there are other approaches capable of delivering better b11si11ess a11 d industry 011tco111es, whilst protecting tire public's desire for protection of t/1eir interests. This paper disc11sses the trends i11 private sector e11gage111e11/ in the A 11stralia11 111ater i11d11stry over 1/1e last decade, and assesses tire direct ions th(// 111ight be p11rs11ed in the next. Keywords: Public private partnerships, Australi a, water, in frastructure, services, in du stry d evelopme nt , in st itutio n al refo rm, pri vatisati on

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procurem ent practices has been promoted by differences between State governments, including ideological approaches to private sector e ngage me nt (especiall y T reasury poli cies on private sector funding of public works) and th e relative liqu idity in State budgets and subsidy programs. H oweve r, the water utility secto r re mains alm ost e ntirely in publi c ow nership , with o nly a few small pri vate townsh ips (e.g., resorts and minin g towns) unde r private ownership. The Sydney Water cornerstone initiative in infrastructure provision Prior to 1990, the service businesses of wate r utilities were implem ented by the u til i ties themselve s a t eve ry level.

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Construction work devolved to th e private sector in the 1970's and 1980's, re fl ecting an acknowledgement of the increasingly internatio na!Jy-competitive capabilities of the Australian construction industry. Sydney Water's major water filtration progra m that commenced at the beginning of the 1990's was the impetus for change to private sector op erational involvement. With no prior experience in very large scale wa ter treatment operations, a management keen to exami ne reform practices (co nsistent with the philosophy of th e then-current State Government), and the development of the suppli er market to include the rapi dly globalising British privatised water utilities alongside the French giants, there was a sign ifi ca nt pretext for Sydney Water to implement three major D esign - Build- FinanceO perate [DB FO] contracts. T he successful impleme ntation of these treatment plants - effectively introducin g leading edge design practice at substantial savings to the budgeted program cost - was the fi rst of two cornerstone contracts in the effective development of, and continuing impetus for, publi c-private partnerships (PP Ps] in the Australian water industry . The Melbourne Water cornerstone initiative in services provision Sydney Water' s initiatives were parallelled by the collapse of the State fina nces in Victoria and the election of a reformist government with a conservative economic policy agenda. Within that T reasury policy context, Melbourne Water did implement a small DBFO proj ect. H owever, of far more significa nce to the evolution of the Australian water industry was their large-sca le outso urcing of water and sewerage systems maintenance activi t i es i n 199 2 . The s u ccess fu l im.p lementation o f that outsourcing program laid the second cornerstone for later programs - by deli vering better quality customer service o utcomes at a significantly lower price, with virtually no industrial action and (typically) better incomes for the outsourced perso nnel.

Status of PPP in water services Several general observations are useful for considering future developm ents: • A wide range of models is available (with varying issues regarding implementation and outcomes), including: fixed price, schedule of rates, fixed price - schedule of rates combination, fixed p rice cost incentive, proj ect Alliance and concession (effectively the mod el for Brisbane Water). • A w ide range of PP P boundary definitions is available, including: maintenance only, systems operation and maintenance, IT sourcing, billing and revenue sourcing, and very high level PPP interfaces - both at and just below strategic planning. • A wide range of scales has been shown to be effective, especially regarding services outso urcing, with the smallest of the current con tracts valu ed at only $6M p er annmn. It was recognised that these contract services harvested the remaining ' lowhangin g fr uit' in workplace refo rm. The second-generation contracts were not expec t ed to re peat th e outcomes, including cost savings. Nonetheless, the success was som ething that the relatively stifled bureaucracies had not bee n able to effectively ach ieve. T hus, the real sign ificance o f Melbourne Water's outsourcing in terms of industry-change value was its demonstration of the value of outsourcing con tracts as a catalytic change-agent. Market change achieved The successfu l implementation of the Sydney and Melbourne contracts had demonstrated the fundame ntal soundness

- i1111ariably better 011/con,es and de111011Strably 110 worse in. a,1y real respect - of engaging the private sector in operational roles in the Australian water industry in addition to the private sector's established capabilities in design and co nstruction. Fundamental to the sustainability of the change initiatives was an accompanying restructuring of the supplier market. The globa l water companies Vivendi, Ondeo and United Utilities - in their different corporate clothing at the time - had each established a major foot hold. T he major British service provider, SerCo , had sec ured one of the Melbourne contracts, cem.enting its recently established contracts in the Defence facilities maintenance sector. Additionally, local construction compan ies T ransfield , Lend Lease, and T hiess Contracto rs had established some

DBFO partnership structu res and so me standalone service capabiliti es.

Developments in Services T he economic driver for the reform in Victoria was also prese nt in South Australia. However, the So uth Australian govern ment pursued a fundamenta lly different path, relying on studies that indi cated th e utilities sector was one of the few sectors capable ofleverage for state economic development. A cluster industty development model was pursued, based arou nd PPPs for its single- entity State water industry, SA Water Corporation. P ropo n ents for Ad e laide' s se r v ice outsourcing and th e $80M DBFO regional water treatment plants program contract were required to offer and agree to binding econom.ic development agreen1.ents . A joint ventu re of Vivend i and T hames W ater sec ured th e Adela id e outsourcing contract. This effectively stabilised these compa ny's business operations in Australia and, given their size and capabilities, the overall supplier competency and capability in Austra lia at a level that could me et almost any marke t eventual ity. Within the next two years, i.e . until 1995 , both the C oliban R egional Water Authority and the Water Corporation of Western Australia had entered into significant services sourcing agreements with the private sector. Both se t important benchmarks for the industty . T he Coliban

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contract was the first, and still th e only, non-metropolitan water ind ustry services co ntra ct of any meaningful size. The Wat e r Corporation sourcing - two contracts covering the north and sou th sides of Perch - were developed and imple mented as Project Alliances. The 'P roject Alliance' model had o nl y recently been introduced to Australia at the time, thro ugh the oil and gas industry in Western Australia. The Perch initiative was the firs t application of th at model within the water industry. It has si n ce been used co implement two subsequent se rvic es contrac ts - the ACTEW Corporation -AccewAGL agreement in C anberra and the NQ Water - C iciwater wa t e r sup ply se rvic es co ntract in Townsville. It has also been in creasi ngly used in infrastructure provision.

Developments in Infrastructure Provision Followin g the success of the Sydney and M elbourne projects, a num ber of othe r utili ties assessed the potential of the DBFO deli very model. Vi ctoria developed a comprehensive set of tools for evaluatin g both o utso urci ng and i nfrastructure PP Ps. Th e present program, Part11erships Victoria, requires continual review of the value of th e DBFO models for public infrastructure and includes an excellent set of gu ideli ne documents for evaluating infrastru cture PP Ps. Several DBFO projects have been im pl e me nte d u n d e r t h e program , inclu d ing leading edge technology applicati ons such as th e 100 ML/ d Sandhu rst water treatment plant fo r Coli ban Water, which uses submerged 'Memcec' crossflow mi crofiltracion m embranes backed by ozone/BAC. A c ri tica l issue is chat the risk profiles have reached the edge of market acceptance; the pri vate sector's ability to abso rb quality and quantity risk has been fu lly tested and screeched . Th e continu ed applicati on of the D BFO model in Victo ria wil l need to pull back th e risk transfer. The conti nued high cost of transactio n management fo r th e DBFO model is also causing some issues. By comparison, the d esign-bu il d-operate [DBO] model, which leaves financ i ng with the gove rnment utility, has been used on a few s mall er projects in Victoria and is gaini n g wide acceptance in the regional areas of the other east coast states of New South Wa les and Queensland. The DB O model was initiall y used in Queensla nd , where legislation (since amended) restricted the application of

Key features of the Project Alliance model: • Non-adversarial contract, constructed by mutual agreement, seeking an equitable balance of risk and reward; • Primary emphasis is on business outcom es with an objective co achieve a "win-

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• All co ntra ctors participating in the alliance ea rn their profit from the sa me pool; • Encouragemen t of openness and co-operation between parties; and • Parties agree not co litigate if som ething goes wrong. State subsidies to infrastructu re delivered unde r th e DBFO model. Financial constraints and policies were not the driver in Queensland as they were in Victoria. R ather, particularly for the small co medium wa ter businesses (mo re preva lent than in Vi ctoria), it was access to the bundled design and operations skills of the priva te seccor. Th e DBO model provided th is, all owing chem to acco mm odate c hanging tec h no logies that required considera bly more scientific skill than was consistently avai lable within the busin esses. The DBO model also offered considerably lower transaction costs, and it has ga ined broad acceptance. Some half a dozen projects have now been implemented across Queensland,

ranging in size from $3 mi lli on co $25 m illion in capi tal va lu e. Th e model has recen tly been adopted in N ew South W ales, with two wastewater projects of $35 and $40 mil.lion capital value currently at tender. In Western Australia , fo ll owing the successful use of th e Project All iance model fo r servi ces outsourcing, the Water Corporation committed co the use of the mo del for the S 125 million Woodman Point wastewater management complex. T he W ater Corporation has subsequently used the P roject Alliance mode l for a nu mber of och er projects; other utilities, particularly Sydney Water, have also sin ce adopted the m.odel and have

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used it for projects valued at up to $450 million. Th ere is an increasingly held view that the m odel is particularly useful fo r redevelopment and upgrade projects, whi ch in volve considerable interaction with the existing utility knowledge base, unavoidable interfaces with current operations, and inherent uncertainty in the state of the existing asset. The continuing (sm all) stream o f maj or p roj ects has established a reasonably competent supplier market, able to provide almost every form of contract. There is considerable scope for furth er skills transfer and private m arket capability development, especially regarding operatio ns activiti es; pursuing this potential would significantly enhance the econo mic potential o f the Australian water industry as a whole, as discussed by Davis, Perkins & D o oley, at the 17th AWA C o nvention, 1998).

Development s in Ownership Compared to service and infrastru cture provision , there has been very little in the way o f public initiatives fo r change in water utility ownership . The corporatisacion models (introducing competitive and tax equivalents whilst retaining public ownership) fall short of the considerable degree of privatisation that has occurred in the electricity, rail, gas and airport sectors. The only publicly mooted privatisation, of the autho r's own organisation ACTEW [Au stralian Capital Territory Electricity and Water] Corporation, saw the electricity business and assets successfully moved into a partnership with the listed Australian gas and electricity business AGL Li mited (to form ActewAGL), but retention of the public ownership of the water business.

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WATER MARCH 2003

Public perceptions constraining privatisation of water services • Water is essential to health, therefore, it should be held in trust for the community . • W ater is a rare conuno dity in " the w orld's driest continent", therefor e, it must be managed in the long-term public interest . Unlike m an y other rare commodities, it is relatively cheap but cannot be transported cost efficiently; making the rarity localized as well as at a synoptic scale . • Private utility businesses, constituted to maximize profits, are motivated to use as much of this rare reso urce as possible, thus j eopardizing the long term interests of the community Water supply and sewerage services are, through their intensive capital network investment, a natural m onopoly; and as a monopoly business need to be tightly regulated in the public interest. Such regulation can only be achieved through public ownership. • Water is 'free', like air, as it is not manufac tured (as is electricity) , and therefore should rem ain 'free' .

The differing trea tment for various types of government owned monopoly assets is a politically-motivated distinction. Energy utility busin esses in a number of States remain in public hands as a matter of government policy. However, public opposition co water privatisation is far more vigorous than it is for other utility sectors. Indeed, in Vi ctoria, home State of more privatisation activity than any other, the Government is proposing specific law to enshrine public ownership of water assets. The accompanying box suggests several fac tors to account for public attitudes. These are a matter of public perception; readers with economic and regulatory orientations will recognize the flaws in these arguments. N evertheless, broad public opinion is readily drawn to them. The technically artificial but economically and socially real cryptosporidium 'crisis' in Sydney demonstrated the political realities of these perceptions and effectively demonstrated to the general public the 'necessity of public ownership '. The technical systemic failure of a publicly owned system in Walkerton, Canada, mattered little in the narrow window in which the Sydney 'crisis' was viewed and managed (similarly for the Auckland power failure). These factors alone suggest that privatisation in the form of conventional trade sale of public water assets is not within any reasonably forecast event horizon in Australia. Further support for this lies in Australia's relatively stable economic conditions. However, different conclusions may be drawn in terms of ownership models, as discussed below.

Potential Directions and Implicat ions for t he Australian Water Industry Directions in Services Recent times in Australia have seen more activity in servi ce contracts than in any other respect. Optimisation through internal change managem ent processes continues to be pursued by those entities with internally sourced service workforces. R ecent 'blind' benchm.arking exercises (UMS, unpublished) show a spread of cost/ quality benchmarks within water utilities engaging in both internally and externally sourced service w orkforces. H owever, on average th e externally sourced workforces were superior in both cost and quality outcomes.


BUSINESS

Given chis result and the trend over the lase decade co externally source facilities maintenance and non-strategic operations, the recent hiatus in outsourcing within the water industry is puzzling. There is no readily observable evidence chat a services outsourcing strategy leads to any n egative business outcomes. C ould political drivers, influenced by public sentiment, be responsible? One could argue that antipathy to further privatisation of T elstra provides circum stantial support for this proposition; indeed, recent research has documented linkages between Telstra's reforms and public perception of privatisation (IDSM & ACA Researc h, 2002, unpublished) . H owever, the overall public position identified by the research showed a balance between negative and neutral/positive sentim ents towards o utsourcing. The research program is notable, as it is the only statistically valid research to specifically consider water utility services outsourcing. A clear implication from the work is that decision-making regarding outsourcing placed with a political entity is likely to respond to the potential loss of marginal votes, despi te other 'rational' factors. This observation leads to the argument that further progress of the indumy requires additional institutional reforms. The alternative, unpalatable and unn ecessary, is co await another government economic collapse. Given that the sm allest institutional entity level at which effective change has b een implemented co date is at che larger end of the regional corporatised utilities in Victoria, there is an argument for consolidation of smaller utilities into regional corporatised water utilities. Potential benefits from consolidation are listed in the box below.

complexity (shortage of internal exp ertise), but with an aversion to private sector capital. 4. For larger water businesses, an 'economically rational' response to increasing technical complexity that includes equal consideration ofDBO and DBFO delivery models as means co manage delivery (capital) and operational (expense) risk. G iven continu ed stable economic conditi ons (wh ich disfavou r DBFO mo dels), the continued spread of DBO and P roject Alliance delive1y models can be expected. Increased use of DBFO models is also constrained by high transaction costs. Transaction efficiency could, according co several commentators, shift if tax ch anges are pursued (viz. Section 51AD and Division 16D of the Comm.on wealth Tax Ac t). Other Implications: Immediate Influences The South Australian initiatives discussed above required a private sector commitment to development of the water industry that benefited the State's economy, based on Porter's theory of industry clusters le was a forthri ght and individualistic move at the time and, even if som e aspects were open to widespread criticism - e.g. the effective eliminatio n of Australian firms from lead roles in the tender process . While the results are not yet readily noticeable within the Australian industry sector, the strategy stands as recognition of the economic development potential of water u tility refo rm processes. The ACTEW Corporation partnership w ith AGL Limited was the second industry reform process co recognise this economic d evelopment potential. The mo del applied for the water business of ACTEW Corporation is that the ActewAGL

Direction in Infrastructure Delivery Presently, there are four key trends/influences in infrastru cture delivery within the Australian water industry. Each rests on the assum.ption that significant benefits can be derived from implem enting major/ complex infrastructure proje c ts through integrated design, construction and operations teams. However, they are distinct in their relative involvement of internal/ external resources: 1. Increased use of Project Alliances and similar relationship contracts, particularly by water businesses committed co maintaining internal operations and service businesses. 2 . Increasing technical co mplexity of trea tment faci lities (i. e. movement from simple rule-based m ethods to complex modelling, requiring experien ced interpretation for both design and ope rations. 3. An increased use ofDBO deli very models by smaller water busin esses, responding p rimarily to increased technical

Potential benefits of consolidating small water utilities • Existing random land bo undaries can be reconfigured to catchment based boundaries (improving stra tegic water cycle planning abilities); • Consolidation of water and sewerage services (separate in parts of N SW), reducing duplicate resources and planning impediments; • D e-politi cisationl of th e principal corporate go vernance entity - from local government councillors to independent boards. T his would allow representative skills-based boards focused on customer and busin ess o utcomes, rathe r than political outcomes; and • Improvements to business syste ms and custom er service outcomes due to the ability of a larger entity to acquire better systems at lower ma rginal costs p er customer.

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partnership (50% owned by each of the public sector ACTEW Corporation and the private sector AGL Limited) nuw provides a scope of services equivalent i11 scope to the typical q_{femiage arrangement in France. At present, detailed financial and risk assessments are reviewing the outcomes of the initial Alliance contract, with the intent to implement conventional broad-scope operations and services contracts over a twenty year term. The full knowledge base of the ACTEW Corporation water sector personnel has thus been leveraged into a PPP business able to effectively compete in the private sector as a nonregulated business. Most importantly, ACTEW Corporation's share of the financial returns from the entire multi-utility business partnership already exceed - after only two years into the business - the returns earned from the electricity and water businesses prior to the formation of the partnership. ACTEW Corporation believes that the partnership model developed is one that many other public sector utilities world-wide should consider. The benefits of the model, and the Berlin /,Vasser model which closely parallels but preceded the ACTEW arrangement, are worthy of comprehensive study.

Direction in Ownership There is little, if any, prospect of a conventional trade-sale or public float privatisation in the Australian water industry's foreseeable future. This is unlikely to occur until a 'privatisation' model is developed that satisfies the public concerns identified above.

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A potential model is a split asset mutual/operating business model - creating two entities, with the core asset owned by a unit infrastructure trust entity and the operation leveraged into a private business, part owned by the community and part sold to the private sector. The unit trust structure could allocate units on a one-per-served property basis, retaining genuine community ownership of the asset and potentially simplifying the issue of gifted assets from new developments. Trust management could be established initially through the existing government owner. The operations business could be established on a franchise or concession model, reflecting the difference between chis outcome and traditional privatisation. Separation of return on assets pricing and commodity pricing outcomes should simplify the regulatory outcomes and create a much more direct link for customers between business outcomes and service pricing. This simple outline presents a case that there are alternatives to traditional privatisation, just as has been implemented with the ActewAGL partnerships. Such proposals warrant further consideration if objectives of sustainable businesses, protection of public interest and industry development are to be the reasons for considering industry reform, rather than simply raising capital. These models must consider the inherent incentives to deliver across all three parts of the triple bottom line: economic, environmental a11d social.

Conclusion Time and study will reveal how to best deliver economic and social benefits through private/public interface options. Arguably, when one is delivering essential environment industty infrastructure and services, the environment bottom line is simply derived from economic and regulatory constraints. Absent authoritative studies, there are still broad opportunities to further develop public private partnerships in Australia. Securing continuing institutional reform - both for smaller water businesses and in restructuring the larger corporatised utilities - is a necessary precursor and perhaps the greatest public policy priority.

The Author Paul Perkins is the Chief Executive of ACTEW Corporation Ltd. This paper is an edited version of a presentation originally made for the Rosenburg Forum in the ACT, October 2002. Email: paul.perkins@actew.com.au

Bibliography Gill, Jim, The Public/Private Spectrum in the Water Services Industry, www.atse.org.au/publications/irc-reports/papcr-southafricanovcmber _1999pl.hon Harford, Peter, Australian Water Industry Experience - Private Industry Involvement, presentation to session on Private Participation in Infrastructure in China, World Bank Group, http://lnweb18.worldbank.org/eap/eap.nsf/ Sectors/Urban+Dev/ Moran, Alan, Privatisation in Australia, www.ipa.org.au/pubs/ Moranwebpapers/amprivint0700sum.html National Competition Council, A Viable and Sustainable Water Industiy: Staff Discus5ion P.1pcr, July 2002 National Council for Public Private Partnerships, A White Paper on Partnerships, For the Good of the People: Using Public Private Partnerships to Meet America's Essential Needs, www.ncppp.org Nea!, Kathy er al, Restructuring America's Water Industry: Comparing Investor-Owned and Government Water Systems, www. rpp i. o rg/ ps200. html Partnerships Victoria, www.partnershlps. vie.gov.au/ Vann, Bradley and Quentin Solomon, Australian-Style Public-Private Partnerships, Prifl11tisr11i<i11 Intmwtio11al, July 2000


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AUSTRALIAN WATER ASSOCIATION SUBMISSION IN RESPONSE TO WATER PROPERTY RIGHTS: REPORT TO COAG FROM THE WATER CEO'S GROUP B McRae Editors note: A vVA 's recent. submission is reproduced below, i11 part. The referenced co11trib11tio11 by the Queensland Branch has not bee11 i11c/11ded, i11 the i11terest ofspare. Also excluded are f ootnoted references contai11ed i,1 tire original. The complete S11bm issio11 a11d a link to th e Water CEO's Group paper are available 011 the A WA website (see below).

Introduction T he Au stralian Water Asso ciation (AWA) welcomes this opportunity to respond to the above- captioned paper. Rather than addressi ng all of the points raised in the paper, th is response seeks to provide som e very sp ecifi c perspectives, driven by the nature of the Association . For e most , AW A wi s hes to acknowledge the enormity of th e task involved in preparing th e paper and commend the Water CEO's Group on the significant effort it represents. It manages to succinctly address a complex subject. T h e Association's primary intention is that th e comm ents below will contribute to this important undertaking. To th e ex tent that thi s contributi on m ay be considered as criticism, it should not be understood to detract from the respect we have for the effort made by the Water CEO's Group and staff The Association's purpose is, quite sin1ply, to promote th e sustainable management of water; a principle that has remain ed large ly un chan ged sin ce AW A's founding forty years ago. We represent over 500 organisations and 3,500 individuals that endorse and support this mission. The issue of water property rights is inseparable from our mission, yet w e acknowledge that the co1n1111111ity whose 'rights' are potentially most affected by any reforms are largely outside our membership, which is broad, but admittedly co ncentrated in the sphere of urban as opposed to rural water management. In saying this, we do not wish to dismiss or diminish the broader rig hts that our members , and all

Australian's, possess in relation to o ur common environmental assets, including water resources, which we hold in high regard. Ho wever, we do wish to acknowledge our respect for rural w ater users as individuals, and the personal challenges likely to arise for them from any reforms. AWA has sought feedbac k from its membershi p regarding the Water CEO's Paper, particularly through its Water M anagement Law & Policy National Special Interest Group. The response has been undervvhelming, most certainly for a variety of reasons, but amongst those , we wish to raise the issue of timing. D espite the granting of an extension of the dea dline for our submission, it precedes th e state m eetings, to our knowledge, for all jurisdictio ns except Queensland. While we understand and respect the reasoning for this, it is to our view problemati c. AWA's Queensland Branch had the benefit of a m eeting and the y ha ve prepa r ed a submission (provided in full at the end of this response) . lt is possible that other AWA Branches will be si1nilarly inspired in due course as mee tings are held in their jurisdictions and it is our intention to forward any additional contributions from them, as they may arise. In addition to the Qu eensland Branch submission, we wish to refer to the paper prepared by Professor Jennifer McKay on property rights, who is the Chair of A WA 's Water Management Law & Policy interest group. Professor M cKay provides a significant contribution to this issue in her 81-page report. Doing justice to her work is not possible without making this submi ss ion unwieldy . Excerpts are provided below, but we also wish to incorpo rate it by reference in its entirety. This response has been drafted by Brian M cR..ae, AWA National office. It has not been possible to consult the entire A WA m e mb ership on th is specific work, but the ideas are built on previous submissions, to which they have had

access. The fo cus is on addressin g specific issues we consider relevant and , in som e cases, not represented in the W ater CEO's Group rep ort. In fairness, th ese un addressed issues may be beyond the scop e of their brief W e submit that they are germane and provide a context that must be considered if the task is to ensure sustainable wate r re so urces managem ent.

The Context Sections 3-20 of the Water CEO's report fall under the heading of "The Context''. While the section is thorough in its coverage of many of the specific issues central to the current property ri ghts debate, it fails to address so me issues that should not be ignored. This is largely an issue of breadth, perhaps best summed up by the obse rvation that this discussion should not be seen to be merely about water rights. Rather, it should be realised that the goal is sustainable management of Australia's water resources, w ith the issue of ri ghts being a ve1y significant part of the agenda previously established by COAG, but only a part. W e shou ld not forget the goal. Inqui ries and Reports Th ere are four recent water- related inquirie s by the C ommonwealth Parliament:

• Co-ordi11ati11g Catchrnent J\II(l/tage111e11/ • A 1,1 stralia's Urba11. Water J\/J.(1/,agement • F11ture wa ter supplies for Australia's mral i11d11stries and co111111r111ities • R11ml liVater R esorace Usage Of these four inquiries, reports have been tabled for the first two. To date, to the best of our knowl edge, there has been no response from government on either of the tabl ed reports , despite th e fact that the Co-ordinating Catclune11t 1\!Ia11age111e11t report was tabled over two years ago. The two completed reports both advocate strongly fo r a strength ened fed era l rol e with respect to water reso urces. WATER MARCH 2003

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Professor McKay has noted that: "The real issues for the law and policy makers at present consist of the lack of data on all dimensions of the reform process." There are a number of reasons for the lack of adequate data, but these impediments are compounded by institutional issues. "Water is a complex system and subject to multiple demands, and neither law nor the regulatory institutions relating to water use are one system, even in any one State. Consequently, the institutions exist in a state of legal 'pluralism' ... '' What is the significance of this observation? Professor fvlcKay's conclusion is that " .. .in Australia, whilst the common law is clear that ownership of surface water rested with the Crown, the problem was that the ways the Crown divested itself of the ownership created beliefs and expectations in the minds of the rural community that paralleled their ownership of it." The situation that we find ourselves in at present can be attributt¡d in part to the outcomes of the Constitutional Conventions which gave rise to the insertion of s.100 of 771c Co11stit11tio11, constraining the federal role with respect to water. This is not to say that the Commonwealth would have 'done a better job' than the states have, but the reality is that water does not recognise political or institutional boundaries. Water is a common resource, a common heritage, and any attempt to manage it in a piecemeal fashion only increases the difficulties of the task. The Co~ordi1iati11,~ Catch111c111 kfa111wc111c111 report is by no means the first recent suggestion that we should, or could, be managing our water resources as a nation. The Commonwealth Environment Powers inquiry report paved the way several years earlier for an increased role, although its recommendations, like the Catchment Management report, have yet to be effected, at least with respect to water. Yet, even that report resorted to citing an earlier source, dating to 1970: ... the Commonwealth has, through a coalescence of Commonwealth power in the fields of taxation, defence, external affairs, meteorology, fishe1ies, quarantine, and other fields, sufficient legislative competence to lay down and enforce a national approach Ito regulate water pollution] through Commonwealth legislation alone. Professor McKay observes that" ... the complexity of the issues in water management has led to legal indeterminacy." It could perhaps also be said 104

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that we have a complexity of inquiries that has led to political indeterminacy. The people's representatives have now said, based on extensive public consultation, in a succession of reports, that we should be coordinating the management of water, and other natural resources, more strongly at the national level. The COAG process is a forum for addressing that issue and the water reforms do represent significant progress. However, they fall far short of the recommendations in the Co-ordinating Catchment 1\;fa,iageme11t report, which have yet to be

debated. Part of the difficulties we are currently faced with, discussed in both the Water CEO's report and the Professor McKay's report, is a lack of adequate data. This issue resides in a range of circumstances, not least of which is the condition of our catchments. The lack of data is relevant to a discussion of allocation, particularly in regards to environmental mitigation, which requires data. What we do on the allocation end to mitigate environmental concerns influences the extent to which we provide compensation/adjustment payments, if any. We do need to address the issue of rights. It has been outstanding on the reform agenda and the potential impacts of leaving the issue unresolved are substantial. However, we also have a body of recommendations in the Coordi11ati11.~ Catc/11nc11t Aia11,l~c111c11t report that are relevant and have not been acted upon. The discussion above, which may seem extended to some, barely scratches the surface of the issue of how we address water policy as a federation. There are other relevant recent reports, notably, but not exclusively, lVatcr 1111d the A11strali1111 Eco110111y, The important message is that water exists in the world as an interconnected system and our disjointed management approaches are ill-suited to sustainable outcomes.

COAG should, as part of its deliberations on water rights, address the issue of these outstanding and pending inquiries and reports, with a view to the states and the Co1n1nonwealth agreeing on ways to provide integrated national approach to 1nanaging catclunents.

Balancing Different Imperatives â&#x20AC;˘ Impediments and Opportunities Section 7 of the Water CEO's report acknowledges that amending entitlements is potentially "inequitable, costly,

or both." Section 8 raises the issue that there is debate regarding ''the extent to which prices should recover the cost of externalities." Section 11, in its fourth impediment, cites the limitations on the use of market discipline where a resource is underpriced, as is the case with water. These are all good points, but their relevance as impediments is potentially constrained by an unnecessarily narrO\v view. Section 18 does touch on the missing perspective, but only superficially, almost dismissively, at least relevant to its potential import. The urban sector has been challenged for some time, both here and overseas, to improve the ~(ficie11cy of its water use. Utilities and their customers, both individuals and businesses, have made substantial investments so that they could continue to use water for the things they need it for, but use less water. As a result, we have seen per capita consumption decline substantially, avoiding or delaying the need to develop new supplies or infrastructure, often for a far lower price. This is not to say that this pattern does not have its equivalent in the rural water sector, but the progress there is arguably less than it has been in the urban sector. The basic premise that runs throughout the Water CEO's paper is that in order to address over-allocation and environmental requirements, rural water users will suffer harm due to decreased allocations. If they wish to pursue 'business as usual', then this is indeed likely to be the case for many. However, for some it may be possible to continue to make a livelihood as they are accustomed to, by adopting new, better practices. In many cases, this will require capital. However, the current debate acknowledges the possibility of compensation/ adjustment funding, This funding could be directed towards the fulfilment of specific policy goals by replacing payments with grants or rebates. This is a very complimentary approach to water trading, providing a market mechanism, but tied to an even greater certainty that water will flow towards higher and better uses. It is also the only logical way to address the problem of pricing inelasticity. Water prices are lower than they should be, but the increase needed to influence demand to any significant extent is outside the bounds of reason. Marginal increases that are within reach can, however, be effective in reducing demand, if the


6. At the sewage treatment plant

7. On-site systems

8 .Effluent management

Tailor the We All Use Water resources to your needs - all aspects are available individually as well. Visit www.awa.asn.au/education or call AWA on 1300 361 426.

( \ Promoting the

AV/f....A

~~ustainable ~ ~ -~ Management ,.;:,:~lo, -......J

of Water


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surplus revenue is reallocated towards funding efficiency improvements. The recent commitments for public funding to study the proposals by Richard Pratt in the Winunera-Mallee system provide an example of the potential to turn dollars into water. On the issue of externalities, Australia does have a potentially instructive model in the recently formed Sydney Catchment Authority (SCA). The SCA is responsible for managing the catchment and providing environmental flows. In this sense, it has a relatively clear imperative to address externalities. Sydney Water must pay the SCA for the bulk supplies it needs. This model provides a potential mechanism for ensuring that the price of water includes the cost of mitigating any environmental impacts associated with the extraction of supplies. There arc various catchment management institutions in the states that emulate this model, however, the SCA has been constituted with a very clear mandate to act as an environmental steward and it has bce11 gil'e/1 l'({crral por/lers to ms11re it has a cha,,cc (if doing the job. Catchments don't need to be managed; nature does a fine job on its own. What do need to be managed are human activities within the catchment. Catchment management is largely about regulating human activity, so the ability to review development proposals, and impose requirements, is essential. Environmental degradation of riparian resources is only partially about withdrawals and flows. Mitigation in some cases will not be successful simply by reducing allocations and it may indeed be possible in some cases without the need to reduce allocations. Section 43 of the Water CEO's report states that: "Strictly speaking, adjustment assistance is provided solely to enable farmers to make an adjustment." What better adjustment and assistance could be provided than to give them the ability to continue 'business as usual'? COAG should consider opportunities to promote water efficiency as part of its discussion of water rights. Con1pensation/adjust1nent funds should be used, ideally exclusively, to promote the uptake of more efficient water use practices. Water pricing should be seen not just as a tool to influence demand and reflect costs, but as a way generate additional inco1ne for de1nand reduction measures. Water rights need not be all about winloose; win-win is possible.

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Property Rights Professor McKay has addressed a number of issues related to property rights at length. Her observations conform to the Water CEO's statement in Section 27 that: " .. .in every state the "right to use and control" of water has for over a century been clearly vested in the Crown ... There is no co11stit11tio11al right in any State to compensation for withdrawal of a resource allocation, if this is carried out legally." Section 22 invokes a potential "duty of care". The issue ofrights should be dealt with fairly, but the legacy of misimpressions regarding rights, as cited above in Professor McKay's work, should not be perpetuated. Section 47 of the report notes that it is ultimately the responsibility of individual jurisdictions to judge the appropriate parameters related to assistance. This is tempered by Section 48, which acknowledges that legitimate cause may exist for Commonwealth financial assistance in this endeavour. We agree with these observations, and leave it for the parties to the federation to reach an accord, however, we suggest that: To the extent that Co1111nonwealth funds are provided, they should be applied under the grants power, constrained to realise specific outco111es.

Additional Thoughts The AW A national office strongly endorses the Queensland Branch suggestion that there is a need for improved river condition assessment, monitoring and research. We would take this one step further, by suggesting this as an area that could benefit from a coordinated national approach. More monitoring is only part of the problem, and v,.rould not necessatily be a satisfacto1y or efficient solution. The National Land and Water Audit, the AusRivas system for stream assessment and other initiatives notwithstanding, there is potentially great overlap and redundancy in data collection. This is a formidable task, but potentially worthwhile. The extent of the overlap, and more importantly perhaps the gaps, can be best understood by providing a common data repository. NSW recently implemented a system, "CANRI", that allows data from a number of different agencies to be accessed against a common spatial platform. The United States Geological Survey now has a system running on the internet that provides current, often real-

time, data regarding stream flow conditions across the nation. In its submission to the Catchment Management inqui1y, AW A noted that an ideal solution would be to reorganise all of the local government boundaries along natural catchment boundaries, providing for unified management of significant activities such as land use planning and responsibility for care of catchments. We also recognised the potential political impracticability of this and suggested that it might be possible to create 'virtual catchments', by providing a common platform to which various responsible parties could contribute data. COAG should actively consider the potential for develop1nent of a unified syste1n for the storage of data frotn 1nonitoring in particular, as well as other infortnation such as land use planning and developi-nent considerations. This submission has not touched on a number of issues discussed in the Water CEO's report. Tvvo of those are ofsufi1cient importance to warrant at least a mention in passing. One is the concept of a national property rights register. We recognise the need for, and extreme importance of, such a system. We note that Mike Young of CS!RO has prepared a paper suggesting an approach, which was published in the Association's journal. We'd like to support the need for a system, but steer dear of prescribing any particular approach. One concern though would be that any system should address both surface and groundwater. These two systems are often interconnected. An attempt to provide environmental flows could be adversely affected by pumping along a riparian corridor. This connection should be considered as part of the design of any system. Second is the concept of providing security to rights for a reasonable period (-10 yrs), \Vith revisions during that period subject to compensation, revisions beyond the period not attracting compensation and provision for an interim review that is science-based and indicates potential outcomes upon license expiry. The basic model provides a good mix of necessary elements and we would strongly endorse it. See w11,111.awa.as11.a11 /11ews&i1ifo/s11b111isM sio11sl for the full s11b111issio11 or co11tact: b111crae@awa.as11.a11

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Water Journal March 2003  

Water Journal March 2003