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Journal of the Australian Water Association
Volume 33 No 4 June 2006
OPINION AND INDUSTRY NEWS OPINION The Challenge for Regional and Rural Water Supplies DDay, President, AWA Water - Who Gets It? CDavis, CEO, AWA VALE GARRY MEINCK, Chief Operations Officer at Water Corporation, Western Australia My Point of View KMatthews, CEO, NWC AWA NEWS Includes: National Specialist Networks; Young Water Professionals; Water Education Network CROSSCURRENT Water Industry News, Projects, Research, Reports, Education and Training, Personalia, Waterscape AWA MEMBERSHIP NEWS New members, AWA/Tenderlink water industry tender portal
4 5 6 10 12 18
PROFESSIONAL DEVELOPMENT NATIONAL EVENT CALENDAR
Water Issues in Mining and other upcoming seminars and events
CONFERENCE REPORTS Enviro 06: The Technical Program Enviro 06: Keynote Address: Is Sustainable Water Resource Management Possible in Australia? 2nd National Water Education Conference: 'From the Water's Edge to the Red Centre'
Report by EA (Bob) Swinton RVertessy
Report by Corinne Cheeseman
ADavey, RSchumann, DDavey
S Rahman, DAl Bakri
TECHNICAL FEATURES I ·, indicates the paper has been refereed) MEMBRANE TECHNOLOGY
Ashkelon - The World's Largest Seawater Reverse Osmosis Desalination Plant Areport from a recent visit
r!l Cost Analysis of Membrane Technology for Wastewater Reclamation Comparing pressure and immersed UF facilities ~ Characterising Wastewater for Ultra Filtration Analysing the organic and inorganic foulants COMMUNITY CONSULTATION
Community-Based Integrated Catchment Management in New Zealand Lessons learned in enhancing national coordination
HYDROLOGY [l¥l Urban Stormwater Hydrology for an Inland City Asignificant contrast to similar-sized coastal catchments INTEGRATED DESIGN Evaluating Modelling Software: The Hidden Features It is worth putting in the effort to determine the true cost/ benefit
WATER BUSINESS NEW PRODUCTS AND BUSINESS INFORMATION - SPECIAL FEATURES: RAINWATER TANK TECHNOLOGY; PRESSURE SEWERAGE SYSTEMS ADVERTISERS' INDEX
The world's largest seawater RO plant at Ashkelon, Israel, is now producing 330 ML/d and hos been voted the Desalination Plant of the Year by the Global Water Awards 2006. Our photograph is in the heart of the RO stage of the plant. More details ore in the article on page 49. Photo courtesy of Veolia Water.
Journa l of the Australian Water Association Water JUNE 2006 l
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2 JUNE 2006
Journal of the Australian Water Association
Volume 33 No 4 June 2006
AWA WATER JOURNAL MISSION STATEMENT 'To provide a print ;ournal that interests and informs on water matters, Australian and international, covering technological, environmental, economic and social aspects, and to provide a repository of useful refereed papers.' PUBLISH DATES Water Journal is published eight times per year: February, March, May, June, August, September, November and December EDITORIAL BOARD: Chairman: FR Bishop BN Anderson, CDiaper GFinke, GFinlayson, GA Holder, BLabza, MMuntisov, CPorter, FRoddick, GRyan, AGibson EDITORIAL SUBMISSIONS Water Journal invites editorial submissions for: Technical Papers and topical articles, Opinion, News, New Products and Business Information. Acceptance of editorial submissions is subject to editorial board discretion. Email your submissions to one of the following three categories: 1. TECHNICAL PAPERS AND FEATURES Bob Swinton, Technical Editor, Water Journal: firstname.lastname@example.org AND http://gemini.econ.umd.edu/wj (Editorial Express) Papers of 3000-4000 words (allowing for graphics); or topical stories of up to 2,000 words. relating to all areas of the water cycle and water business. Submissions are tabled at monthly editorial board meetings and where appropriate are assigned to referees. Referee comments will be forwarded to the principal author for further action. See box on page 51 for more details. 2. OPINION, INDUSTRY NEWS, PROFESSIONAL DEVELOPMENT Sue Corlette: Marketing Communications Manager, AWA, email@example.com Articles of 1000 words or less 3. WATER BUSINESS Brian Rault, National Sales & Advertising Manager, Hallmark Editions firstname.lastname@example.org Water Business updates readers on new products and associated business news within the water sector. ADVERTISING Brian Rault, National Sales & Advertising Manager, Hallmark Editions Tel: 61 3 8S34 S014 (direct), 6138S34 S000 (switch), email@example.com Advertisements are included as an information service to readers and are reviewed before publication to ensure relevance to the water environment and objectives of AWA. PURCHASING WATER JOURNAL Single issues available@ $12.50 plus postage and handling; email firstname.lastname@example.org BACK ISSUES Water Journal back issues are available to AWA members at www.awa.asn.au PUBLISHER Hallmark Editions, PO BOX 84, HAMPTON, VICTORIA 3188 Tel: 61 3 8534 5000 Fax: 61 3 9530 8911 Email: email@example.com
Journal of the Australian Water Association
overseen by ESCWARI (the Executive Standing Com mittee in Water resources Infor mation) and rhe WRON seeks to build on this. The vision is fo r a looselycoupled federation of information services, joined together using web services, just as is done with ai rl ine booking systems. What will be involved?
audits and Scace of the Environment reports. Sensorisarion. Rob highlighted that advances in the accuracy, cost and prevalence of environmental sensors (both satellite and in-situ) will be needed to improve the currency and coverage of water resources informatio n.
Reporting. Some is already in progress, with most Scares now serving up large data secs via rhe web. However, more work needs to be done for this information to become live and accessible to web services such as online fo recasting systems, or for the data to harmoni sed for the pu rpose of national assess men rs .
Forecasting. Fi nally, Rob argued that if we can significa ntly improve om water data assets then there will be huge spin-off benefits for hydrologic forecasting. He cited the eWarer CRC's Catchment Modelli ng T oolkit as an excellent example of a group of hydrologic models chat would be hugely enhanced by rhe WRON.
3. Developing rhe consistent Water Resomce Markup Language (WRML) with eWare r, AWDIP, ESCWARI.
Data In tegration in geo-spacial context. Rob made reference to the huge diversity and vol ume of water resources info rmation, highlighting che challenges of reconciling information on wate r availabil ity, demand, entitlements and usage. He stressed chat chis would be one of the key values of the WRON; permitting such reconcil iations to made across Australia, using standard, accredited methods. This is an ability chat has eluded us in national land and water resource
Scarring in 2006 a ten-year program is planned. le involves:
Commenci ng engagement at a range of levels.
Rob concluded by saying that the timing fo r the WRON is perfect. Water is on rhe political agenda as never before an d rhe need for a seep change in the visib ility, currency and depth of hydrologic informa tion is writ large in the National Water Initiative, Austral ia's blueprint for water reform.
2. Commencing a fo undation research program in CSIRO's 'Water for a Healthy Country' Flagship.
Though this was by no means the final paper of Enviro 06, it is a fitting note on which to end this briefreport.
1. Formalising rhe WRON Alliance, including governance arrangemenrs. Extending WRON Alliance to include key end users.
Scoping up two or three 'WRON demonstrators' with end-users and seeking fu nding support from the National Water Commission (NWC). This work would build on the early work of the WRON Alliance in helping the NWC pre pare rhe national basel ine assessment of water resources.
Conti nu ing fasr- rrack developme n t of prototype technologies. Negotiating data sharing methodologies with data custodians.
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Journal of the Australian Water Association
JUNE 2006 4 3
ENVIRO 06: IS SUSTAINABLE WATER RESOURCE MANAGEMENT POSSIBLE IN AUSTRALIA? Keynote address by Dr Rob Vertessy, Chief of CS/RO Land and Water (A summary prepared by Bob Swinton) Sustainable activities allow the needs of the present generation to be met without compromising the needs of future generations.
Australia Annual Mean T Anomaly (base 1961-90}
This implies an equitable distribution of resources not only spatially between users in a given location, but temporally between users over time, and also providing an adequate share to all (including the environmen t) without making any recipient worse off, both now and in the future.
"' ~ G)
We thus need to be able to define what is an adequate share, both for society (users) and the environment.
We also need to be able to anticipate how resource availability and demand will change in the fu tu re. Over the coming years, all Australians will be challenged by a deepening water scarcity problem as demand increases and 'natural' supply diminishes. Figure 1, from the BOM web-site, demonstrates the steady increase in temperature. There is a corresponding southward shift of the rainband, and the frequency and intensity of drought appears to be increasing. Nicholls, N. (2004) in The Changing Nature ofAustralian Droughts, Climatic Change, 63: 323-336. has shown that both maximum and minimum daily temperatures in the Murray Darling Basin increasing from one drought to the next, relative to similar total rainfalls. A broader trend was demonstrated by Mike Raupach, CSIRO, who mapped a remotesensing surrogate of soil moisture, month by month, across the conti nent, for the period 1981 to 2003. The overall shift from blue (moist) to red (dry), is dramatic, revealing the intensity of the drying period Australia entered into at the start of this century. The effects of this drying are reflected in the catchments of both major and smaller cities across the nation, Perth being a prime example. The declines shown in Figures 2 and 3 are well-known, and there are many other cities where water restrictions are being imposed. In the long-term, say 2030, WSM has estimated that all our cities will 44 JUNE 2006
Source: BoM, SILO web site.
Figure 1. Australian mean temperature is increasing . have to reduce per capita consumption by about 40% unless their water supplies are augmented. In the rural scene, surface and groundwater supplies are heavily- and sometimes overallocated, and this is at a time when the Living Murray Initiative seeks to recover 500 GL of water from the system to enhance river health. And looking ahead, it is likely that it will become harder to ensure adequate environmental flows for the river as catchment inflows look set to decrease.
Inflows into the Murray system are likely to reduce significantly over the coming years due to a range of factors. Improved irrigation efficiency is likely to reduce return flows to rivers, and increasing groundwater extraction (see Figure 4) will reduce river baseflows. Landcover changes such as plantation expansion and native forest recovery from bushfires are also predicted to lower catchment yields. Farm dams are proliferating, and although there has been little work on assessing their
1976-2003 average: 276 mm
450 400 E
350 300 250 200
1925-1975 average: 323 mm 150 1925
Figure 2. May-July rainfall tota ls averaged over south-west WA
Journal of the Australian Water Association
conference reports hydrologic impacts, it is clear that they are having a significant impact on catch ment runoff. Finally, climate change, leading to higher temperatures and lower rainfall, will mean signifi cantly less catch ment runoff. Land and water managers are now well aware of these problems and together we face significant technical and policy challenges in dealing with increasing water scarcity, both in rural and urban water contexts. Yet we seem to be less prepared to deal with these challenges than ever before, because of two factors: • Two decades of organisational change - Proliferation of agencies - reduced power to purchase information
= Annual inflow
ii: 700 0
c:: .5 600
= = " i
500 400 300
!- 200 100
"' ~ N
- 1997-2004(115 GL)
Source: WA Water Corporation .
Figure 3. Annual inflows to Perth's dams have declined markedly.
- Agency fiscal pressures - reduced monitoring and field investigations - Diminution of technical capacity in agencies - more outsourcing, less memory • Changes in the R&D scene - Market distortion - R&D is now more tactical and short-term - Efficacy of R&D institutions (themselves under fisca l pressures) eroded -AWRC -AWRAC - LWRRDC- LWA changes • However, recently some positive steps have emerged ... - the performance of the Water CRCs and increased investment in water research in CSIRO
Source: BRS Science for Decision Makers (Feb. 2006).
- Emergence of the NWC (and water resource assessments) - Commonwealth agencies working closer together.
Conclusion Given the seriousness of the water scarcity issue, I doubt that we can: • Provide an adequate share to all (including the environment) without making any recipien t worse off, both now and in the future.
Unless, we can: • Better anticipate spatial and temporal changes in water availability and demand. • Better defin e what is an adequate share, both for users and the environment. • With sufficient warning, establish new infrastructure and shape demand.
And this will require: • Rebuilding technical capacity in the water industry. • Significantly enhancing water resources monitoring, investigation and analysis. • Signifi cantly boosting water R&D. • Significantly boosting consultation with the community and industry.
46 JUNE 2006
Figure 4. Groundwater extractions by region, 1983-4 and 1996-7. Source BRS.
MAPES: MAYORS ASIA PACIFIC ENVIRONMENT SUMMIT This conference, run triennially, was organised chis year to run simultaneously with Enviro 06, so chat local government leaders in our region could derive benefit, particularly from the Exhibition. We were invited to attend one of their plenary sessions, and it was an eye-opener for this reporter. Jerry Harris, retired Mayor of Honolulu, is the founder of MAPES, and began his address by announcing that this was the beginning of the Asia-Pacific century, with 3.5 billion rising co 5 billion people in five years, most with rapidly developing economies. However, the challenge is to attain sustainability when the extra population, which will nearly all be concentrated into cities, will require the equivalent of establishing a city the size of San Francisco .. . every five days. T he ensuing d iscussion covered centralised versus decentralised infrastructure,
Journal of the Australian Water Association
learning from the mistakes of the past and the West when planning for greenfi eld development, the necessity for leaders to have an informed electorate, and the huge advantage offered by advances in communication via the web. However, for me tl1e high spot was the system of achievement awards. Ar the preceding summit, seven Mayors, or their equivalents, had committed themselves to achieve a specified advance in environmental improvement. Cities in Cambodia, India, Maldives, Jakarta and J ogjakarta, Thailand and Vietnam were all honoured for achieving their targets, which ranged from water supply, sanitation, energy efficiency, air pollution control to solid waste management. Later in their conference another group of mayors committed themselves to achieve similar targets. The approval of their peers provides a keen incentive.
2ND NATIONAL WATER EDUCATION CONFERENCE: 'FROM THE WATER'S EDGE TO THE RED CENTRE' April 2006, Alice Springs NT Report by Corinne Cheeseman Education, of the communi ty and of water professionals, is now making a significant concribucion to che water industry and wi ll continue to be viral in the future. Evidence of ch is is char community awareness about water nationally is ac an all time high and that ic is widely recognised chat professional development and training will play a crucial role as the water industry skills shortage takes hold. The 2nd Water Ed ucation Conference held in Alice Springs recently brought together chose involved in ed ucation of the community and water industry pro fess ionals. Perhaps confirmation tha t education is crucial to water management is the mainstream media interest about water ed ucation both locally and nationally wich more than a dozen media items (radio and print) recorded in conjunction with the conference. The success and standard of the conference was contributed to by sponsors; Power and Water Corpo ration (Platinum spo nsor) and ICE WaRM (Bronze sponsor). In add ition to fin ancial support provided by Power and Water Corporation in kind support by the organisations scaff was substantial and
contributed to a seamless event that beneficed enormously from local contributions. In total, 140 delegates attended workshops and presentations across the three conference themes: 'Going with the Flow or
Leading the Way?'.Âˇ 'Creating a Climate of Change' and 'Making a Splash.''. Keynote
speakers Paul Perkins (Australian National University), Blair Nancarrow (Australian Resea rch Centre for Water in Society) and Stuart W hite (Institute for Sustainable Futures) gave provocative presentations stim ul ating thought about che chall enges chat lie ahead for ed ucators and communicators in che water sector.
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Journal of the Australian Water Association
JUNE 2006 47
conference reports H om estead added to rhe experience and cemented professional relationships which will no doubt connnue.
International speaker Lorraine Loken, of rhe Water Environment Federation (WEF) gave an excellent paper o n rhe US water situation, the education activities provided by WEF a nd acknowledged o p portunities rhar Australia has nationally through rhe WEN. Lorraine also spoke at rhe Australian Junior Water P rize (AJWP) Ceremony, sharing her experiences of rhe international compe tition in Stockholm , Sweden. AJWP 2006 winners L inda Van a nd Alex DeSousa of Sr J am es College in Brisbane will represent Australia in August this year. Local schools both primary and secondary we re also invited to participate in the conference. Primary students had the unique opportunity to hear story-telli ng about water challenges in PNG by rwo of the Papua New Guinean delegates who secured funding to attend the con ference. Local high school students were able to learn about th e projects Keynote speaker Blair Nancarrow (ARCWS) that the Australian Junior Water Prize delivering her address on 20 April. finalists h ad worked on for the competition giving the oppor tunity pathways as well as university, vocatio nal for students to com pare a nd contrast water and C RC perspectives. W ithin th is stream issues in Central Australia a nd the East the Water Industry Capacity Development Coast of Australia. (WICD) Reference Com mittee met to Papers and workshops in the school and community education streams covered topics such as: remote indigenous community water m anagemen t, permanent water conservation measures, b ehaviour c hange, building capacity in com munities, organisational education, tools and m ethods of engagemen t and showcased education programs and initiatives of water utilities, local government, state gove rnment and Australian government agencies . In the water industry training and p rofessional development stream papers covered topics such as: the industry skills council and rhe water industry training package, workforce skills challenges, case studies in workplace competency based training and professional developmen t, the role of e-learning, irrigation trainin g
discuss the skills issues fac ing the industry. A meeting of huma n resources professionals from the water industry also m et to discuss raising the profile of the water industry to encourage youth to consider careers in water. P rofessionally facilitated Clearwater Workshops were held in conjunction with the confere nce giving delegates the opportunity to develop skills in the areas of 'Leadership' and 'Evaluation'. In addition, many of rhe confere nce workshops offered within rhe conferen ce streams provided delegates with excellent cools and methods rhat will enh an ce their education initiatives and progra ms. The confere nce functions that rook place under the am azing o utback sky at Alice Springs Desert Park and Ooraminna
T h e exhi bition, run for the first time in conjunction with the conference, provided a great space fo r nerworking a nd sampling some of the country's b est education initiatives and programs . In total there were 14 exhibitors: Firestarter P ry Ltd, Power and Water Corporation, Gold Coast Water, Water Corporatio n , Sydney Catchment Authority, ACTEW Corpora tion , Melbourne Water, Water - Learn It! Live Ir!, NSW Departme nt of Primary Industries, Centre fo r Groundwater Studies, Leaders in Water Q uality Training, Alice Springs Water Resource Strategy, Water Education Awards a nd Wide Bay T AFE. Overall the conference, the first of its kind since the WEN was established, was a huge success. I t is such a pleasure being in the p resence of those who work in education and communications as by their na ture they have a great d eal of enthusiasm a nd passion for their work. This is why rhe atmosphere at events that involve 'educatio n' is so frie ndly and exciting at the same time. Ir is amazing to see the networking and sh aring of ideas and initiatives rake place - as you would expect delegates from this p rofessional area a re highly skilled com municato rs. AWA's next water education conference will build on the achievements of the 2006 conferen ce and will take place on the Gold Co ast, Queensland 30 March- 1 April 2008. Gold Coast Water is proud to be the platinum sponsor of chis event however ocher excelle nt opportunities exist - secu re your package early to maximise exposure.
For details about the 2006 or 2008 education conference contact Corinne Cheeseman at firstname.lastname@example.org or visit the website http://www.awa.asn.au/eventsl educationconfiJB.
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48 JUNE 2006
Journal of the Australian Water Association
ASHKELON - THE WORLD'S LARGEST SEAWATER REVERSE OSMOSIS DESALINATION PLANT K Craig, B Sauvet-Goichon Introduction
Membranes , l st stage
T he Ashkelon seawater reverse osmosis (SWRO) is currently the world's largest desalination plant relying on memb rane technology and is now providing 330 ML/day of drinking water fol lowing the plant commissioning in 2005. T he plant is owned and operated by YID Desalination Company Lrd, a consortium of Veolia Water and its two Israeli partners, IDE Technologies Ltd and £ Iran Infrastructures Ltd under a 25 year BOOT contract. T he contract guarantees a production capacity of 110 million m3/yr. This plan t is part of a desalination master plan launched by Israel in 2000 to help address the country's chronic water resource problem which is due to limited natural water resources, increased demand fo r water due to population and economic growth and saline ingress into the existing water supplies.
One of the lowest water prices (US $0.53/m3) ever offered for SWRO. The Ashkelon plant is located in sou thern Israel and is contributing to southern Israeli cities. The production is around 15% of the water consumption in the domestic sector.
Ashko/on dosalinetion plant Process dl&grom
Ashkelon process schematic. has achieved one of the lowest water prices (US $0.53/111 3) ever offered fo r this kind of operation.
• Reverse osmosis • Pose-treatment (remineralisation and chlorinatio n)
T he Ashkelon plant includes the fo llowing process units:
T he key parameters for the Ashkelon plant are:
• 110 mill ion 111 3 /year maximum production capacity • Pump station • l 00 million m3/year government • Pre-treatment system (dual media contact purchase agreement A dedicated co mbined cycle gas turbine filtration and cartridge filtration) (cogeneration) power station has • US $0.527/ m3 water price been installed as part of the project. • 75,000 m2 (300 x 200 m) plant Water quality data The power station is designed to footprint supply 80 MW, 56 MW of which Feed seawater temperature l 5°C to 30°C • < 3.9 kWh/111 3 maximum will be used by the desalination Feed seawater sal inity 40,679 mg/ LTDS nominal electrical co nsumption plant. Product water before post-treatment < 80 mg/ LTDS O peration reliability and robustness The use of advanced reverse osmosis < 20 mg/ LCl have been a key priority in the (RO) technology, srare-of-the-art design process. The plant fo rms < 40 mg/ LNo energy recovery system to reduce essentially two independent < 0.4 mg/ LBoron operating costs and contractual facilities, each operating Product water ofter post-treatment < 300 mg/ LTDS strucrnre with proper risk allocarion independently to provide 165 Project Timing ML/day of drin king water. T he Construction started April 2003 The Ashkelon pla nt was awarded seawater intake, pumping station Sub phase 1-2 completion July 2005 "Desalination Plane of the Year" through and the final pose-treatment are the Global Water Awards 2006. Sub phase 3 - Final completion December 2005 common to both stages bur have • Offshore intake pipe
Journal of the Australian Water Association
Water JUNE 2006 49
been designed with sufficient fl exibility to allow separate operation of each plant.
Offshore Intake Pipe and Pump Station D ue to plant capacity and site issues the decision was mad e to build an open submerged type sea intake fac ility. T his system includes three parallel high density polyethylene pipes (ON 1600 - Length 1000 m), which provides redundancy and ensu re contin uous su pply of seawater to the plan t. The polyethylen e p ip ing is simple to clean by pigging and relatively resistant to marine growth. T he intake pum ping station is equipped with five vertical pu mps each su pplying 35 ML/day.
Seawater Intake and Pre-treatment From th e pum ping station, raw seawater is sent to the two pre-treat ment process stages through two separate lines, each feeding 20 d ual media gravity fil ters. Chemicals are ad ded and mixed via static mixers before the filtrat ion stage. The use o f ferric sulfate as coagu lant, an d su lfuric acid for pH adjustment, allows an op timum SDI reduction through the pretreatment stage. Polymer additio n is p rovided to allow adeq uate treatment in the case of seawater deterioration. Sh ock chlorination is also p rovided to control biological growth in the intake and p re-treatment stage. The chemical treatmen t system has sufficient redu ndancy to ensure system availability. Filtration is th rough gravity filte rs containing q uarcz sand and anthracite media with a filtration velocity of 8 m /h. T h e comb ination of chis low velocity, the long reten tion rime and a distribution and collecting underdrain system designed to avoid p referential channel for mation provides high fi ltratio n efficiency. Even with storm turbidity levels; th e fil tered seawater is of su fficien cly h igh quality fo r the RO treatment stage. T h e filters are automatically backwashed every two days.
Ashkelon desalination plant.
approach increases the flexibility of the system and its efficiency. Each desalination faci lity consists of a four passes system. This design was developed in order to achieve the permeate water q uality criteria o f chloride less than 20 mg/Land boron less than 0 .4 mg/L. • T he firs t pass is a conventional seawater RO system. It is operated with a recovery around 45%. A part of permeate is collected from the feed side of the pressure vessels. This part has a lower concentration of sal es (b oron) than the whole permeate, and can be mixed d ireccly w ith the permeate water from the ocher stages. • The rear permeate from rhe fi rst stage feeds the second pass which operates at a high pH to increase the boron reject by the membranes. This pass is operated at 85% recovery. T he permeate from chis stage is part of the final product. • The brine of the second pass is senc as feed to rhe third pass. The third pass acts as a softener of the second pass b rine. Th is
A set of cartridge fi lters (5 µm) provides a fi n al safety barrier before the membranes.
50 JUNE 2006
• T he fourth pass, operated at 90% recovery and high pH, completes the boron removal of the second pass brine. Thus created, the fourth pass permeate is suitable fo r mixing with the fi nal p roduce. A standard two pass p rocess with the second pass brine directed to rhe feed of the first pass was nor acceptable d ue to the h igh bo ron concentration in the brine. Various options were stud ied during the design stage, including the d ischarge of the brine to the d rain and rhe use of bo ron selective io n-exchangers. The water price was a key parameter in determini ng the o ptimum p rocess and final design. T h e desalination facility consists of thirty two RO trains fo r the first pass, eight trains fo r the second pass, two trains for the third pass and two trains for the fo urth pass. T here are 25,600 mem branes of seawater type and 15,10 0 membranes of b rackish water type. Dow Filmtec mem branes have been selected fo r the RO operation. Bri ne fro m the plane is d isposed by mixing in to the adjacent power station cooling water ouclet to ach ieve d ilution. T he brine d isposal is 1300 m from the seawater in take.
Reverse Osmosis T he filtered seawater flows to the reverse osmosis process through high pressure pumps, associated with in novative and efficient Dou ble Work Exchanger En ergy Recovery (DWEER) devices. High pressu re pum ps and energy recovery devices can be operated independencly of each ocher. This
pass is operated at 85% recovery and under low pH. D ue to the low pH, there is no issue with scaling on the mem brane surface, even at h igh recovery and h igh b rine concentration. But at low pH boron rejection is low and some bo ron remains in the third pass permeate. T his permeate is therefore produce water created through the fourth pass.
Seawater intake installation.
Journal of the Australian Water Association
The fi nal water quality in terms of boron and chloride levels is achieved after the m ultip le pass RO system.
water Editorial Submissions Technical Papers
High pressure centre.
Cartridge pre-filters and first pass RO.
DWEER energy recovery centre.
Pose-treatment wich limestone fil ters is then used co rem ineralise the product water before distribu tion in the national water system. Remineralisacion and adjustment of alkalini ty, hardness and pH are necessary co cope with the drinking water quality standards and co prevent any corrosion effects in the distribution network.
In che DWEER energy recovery system the high pressure pump flow rare is equal to rhe product water flow rate. High pressure brine from the membranes is sent to the DWEER work exchanger vessel filled with pre-treated seawater and pressuri ses char seawater ro brine pressure across a piston. A recirculati ng pum p boosts the pressure of the seawater leavi ng the work exchanger vessel co equal che pressure of che high pressure pumps (overcoming membrane piping and DWEER pressure losses ~ 2 bar) and then joins the flow from the high pressure pump.
Innovation and Energy Recovery T he traditional concept of RO trains including a high pressure pump, energy recovery curbine and membranes is not optimal for large scale desalination plants. A centralised rather than local approach has been developed at the Ashkelon plan t. Pumping seawater co high pressure in a centralised system is more economical and the same applies co energy recovery. For each half of the plant, three high pressure pumps form a pumping centre which supplies seawater to all RO trains through a common line. One pump is installed as a stand-by. The energy recovery centre is based on forty DWEERs (ten blocks, fo ur DWEERs in each block with one block in stand-by).
As the end of the cycle nears, a valve diverts the high pressure brine to the opposite work exchanger vessel. The low pressure seawater (from che same source feeding the high pressure pump) then fills rhe spent DWEER work exchanger vessel filled with pre-treated seawater displacing the brine to discharge and the cycle repeats itself. T his system allows over 95% energy recovery and the centralised approach to energy recovery allows flexibility and efficiency of the system.
\11/ater journal welcomes the submission of papers equivalent to 3,000-4,000 words (allowing for graphics) relating to all areas of the water cycle and water business to be published in the journal. Topical stories of up to 2,000 words may also be accepted. All submissions of papers intended fo r the main body of the journal should be emailed to the Technical Editor, firstname.lastname@example.org and http://gemini.econ.umd.edu/wj (Editorial Express). Shorter news items should be emailed to email@example.com. A submitted paper will be tabled at a monthly Journal Committee meeting where, if appropriate, it will be assigned to referees. Their com ments will be passed back to the principal author. Jf accepted and after any comments have been dealr with, the final paper can be emailed with the text in MS Word bur with high resolution graphics (300 dpi riff, jpg or cps files) as separate files. Authors should be mindful that Water jottmal is published in a 3 column 'magazine' format rather rhan the full-page format of Word documents. Graphics should be set up so char they will still be clearly legible when reduced ro two-column size (about 12cm wide). Tables and figures need to be numbered with the appropriate reference in the text e.g. see Figure 1, not just placed in the text with a (see below) reference as they may end up anywhere on the page when typeset. See index page 2 for more details on this and other editorial submissions.
Summary The 330 ML/day Ashkelon plant has demonstrated seawater reverse osmosis technology on a large scale with one of the lowest water prices for a desalination pl ant. The use of an energy recovery system and centralised pum pi ng system has combined co provide low electrical consumption of < 3.9 kW h/ m3 . The plant has met all design and operation parameter requirements and is supplying high quality potable water ro rhe national water system.
The Authors Keith Craig is Technical Director for Veolia Water Australia, email: firstname.lastname@example.org; Bruno Sauvet-Goichon is Internacional Vice President of Veolia Water Systems Desalination Department based in Paris, email: email@example.com
Journal of the Australian Water Association
JUNE 2006 51
technical features refereed paper
COST ANALYSIS OF MEMBRANE TECHNOLOGY FOR WASTEWATER RECLAMATION D Young, C Hertle Summary
• M TP footprint requirements; and
Wastewater reclamation utilising membrane technology provid es a new opportunity to provide high standard Class A+ recycled water, suitable for reuse applications in community environments.
• A financial assessmen t (concept design level) of a MTP facility co mparin g membran e technologies for different treatment capacities. This will include capi tal, operations and maintenance, NPV cost analysis, and production cost estimates.
This paper reviews the manufacturers' specifi cations for four types o f membrane and conducts a finan cial analysis for hypothetical membrane treatment p lants of capacities berween 6 to 24 ML/d Whilst a pressurised ultrafilcration facility has a lower capital cost, resulcs indicate that an immersed ulcrafilcration facil ity has significant operation and "whole of life" (NPV) cost savings for projects greater than 6 ML/d. For an immersed ulcrafilt ration facility the estimated cost of p roduction ranged berween 53 c/kL fo r a 6 ML/d facility to 27 c/kL for a 24 M L/d facility, whilst for a pressurised ultrafilcracion faci lity it was estimated at 56 c/kL for a 6 ML/d facility to 37 c/kL for a 24 M L/d faci lity.
Keywords: Membrane Treatment Plant, ultrafiltration, microfilcration, memb ranes, effiuent reuse, wastewater reclamation, recycled water.
Introduction There is increasing interest by industry and local government au thorities in the use of membrane technology for the treatment of wastewater to p rovide high quality (Class A+) recycled water for re-use applications. The Memb rane Treatment Plant (MTP) offers the ability to produce Class A+ quality effluent, a significant advantage over conventional tertiary treatment systems. Class A+ water is suitable fo r do mestic (non-potable) reuse applications with h igh levels of human contact and a med ium risk ofingescion (QLD EPA, 2005 ). This paper will d iscuss the following:
• An overview of membrane technologies suitable for wastewater reclamation; • MTP design basis and recom mended p rocess to ensure Class A+ reuse standard; • A comparison of Zenon, Microza, NORIT, US Filter membrane technologies;
Immersed UP has higher capital, but lower operating cost, and is better for larger plants.
modular skid mounted units and higher flux rates (at the expense of higher pumping coses). Immersed systems have lower en ergy demands and are capable of handling infl uent feeds with a higher total suspended solids load.
Membranes investigated in this study A number of reputable Australian suppliers were contacted regarding membrane types. The following membrane systems were recommended: •
The specifications of these membrane types are summarised in Table 1. It is noted that some of the seated flux races p rovided by suppliers appear to be h igher than what GHD wo uld expect based on experience and research literature (Lozier, 2003) .
Microfiltration and ultrofiltrotion The principle of microfilcracion (MF) and ulrrafiltration (UF) is physical separation. The extent to which dissolved solids, turbidity and microorganisms are removed is d etermined by che size of rhe pores in rhe membranes and rhe integri ty of the membranes. Substances that are larger than the pores in rhe membran es are fully removed. Substances ch ar are smaller than rhe pores of the membranes are either partially removed or pass through the membrane as permeate. Membranes with a pore size of O.l - 10 µm are generally classified as achieving microfil cration (MF). Ulcrafiltration (UF) is a separation p rocess using membranes with pore sizes in che range of 0.002 to 0.1 micron. There are essentially rwo membrane treatment system co nfigu rations: •
Pressurised systems pump water directly into che membrane module, a housing that contains bundles of several thousands of the membrane fibres. In an immersed system the membranes are submerged in a raw tank of water and the h ead above the membrane combines with the suction draw fro m filte red water pumps. Pressurised systems have the advantage of a smaller footp rint,
Journal of the Australian Water Association
Process requirements Wastewater reclamation using m embranes is a relatively new technology in Australia. A conservative ap proach to p rocess design is recom mended to minimise the risk to the public consumers. To achieve Class A+ water it was considered that UF technology was more suitable compared to MF. MF systems have limited capacity to remove viruses (QLD EPA (a), 20 04; Kramer et al. , 2003; Metcalf and Eddy, 2003; Sakaj i, 20 0 1), and were not considered further in this study. The multi-barrier ap proach is considered a best practice app roach and is based on experience an d guidelines fro m th e fo llowing sources: • A risk management strategy to meet the Queensland Gu idelines for che Safe Use of Recycled Water (QLD EPA (a), 2004). Mr Ken H artley performed research for th is scudy. • California's Surface Water Treatment Regulations (CSWTR) which state that a water supplier is required to provide "mulcibarrier treatment" or a series of water treatment processes char provide fo r the
Table 1. Specifications of microfiltration and ultrafiltration mem branes investigated in this study. System
Immersed microfiltration (IMF)
Pressurised microfiltration (PMF)
Pressurised ultrafiltration (PUF)
Immersed ultrafiltrotion (IUF)
US Filter (CMF-S)
Zenon (ZeeWeed 5001
Membrane supply Flux ll/m 2/ h) Pore size (um) Operating Mode
Protozoa log reduction
li mited removal
Virus log reduction
4-6 2· 4
Approachi ng 100%
3-6 log removal.
3-6 log removal.
Precipitates and Coagulants reduction
Approach ing 100%
limited to no removal
limited to no removal
limited to no removal
<0.1 bar 9.5 (max)
2 bar 4-6
2 bar 5-7.5
Membrane life guaranteed (years)
Nutrients and TDS reduction Pre-treatment requirements filtration Operating pressure Backwash (% infl uent)
Limited to no removal Rotary screenings/ di
<0. 1 bar 5-7.5
References: US Dept Bureau of Reclamation 1993, Metcalf and Eddy 2003, Osmoflo 2004, Ionics 2004 and Memcor 2004. removal and inactivation of waterborne pa thogens. (Lozier et. al. , 2003, Sakaji R., 2001 ). • Overseas wastewater reuse treatm ent planes (S ingapore NEW ater, Californi a Gwinett Co un ty, South Afri ca Windhoek). T he multi -barrier approach provides multi ple processes in series chat when
co mbined ensure a ro bust process that ac hieves the process object ive. Indivi dual processes do not necessari ly achieve the overall obj ective by themselves. Un it processes in se ri es also provide the benefi t of redu cing the load and stress on indi vidual processes (furth er redu cin g the risk o f process
fa ilure). For exa mpl e, sa nd fi j ters provide a pre-filtra tion seep e nsurin g ch at a minimal so lids load an d minim al fo ul ing par ticles (as well as no sharp parti cles) enter the membran es. The rwo main requirements co produce Class A+ reuse standard effl uent (QLD EPA, 2005) are:
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• Tomohiro Kawasaki, Senior Software Engineer at Tokyo Gas, who will explain the Development and Application of Cellular Phone GIS at Tokyo Gas ... the world's largest utility; and • Thierry Gregorius, Programme Manager for Geomatics and Information Management at Shell's international headquarters in the Netherlands, who will address Business Success in an Industry Largely Driven by Geographic Factors. In addition, there will be key presentations from leading international representatives of Oracle Spatial, ESRI, Intergraph and GE. For further details see www.gita.org.au or contact Deanna Zammit on +61 3 9372 7728 or at firstname.lastname@example.org
GEOSrATVJJ INFORMATION &: THCHNOJ..OGY ASSOCI.ATIO N •
Journal of the Australian Water Association
JUNE 2006 53
• Disinfection (<l 500/oile and <10 maximum cfu/ l 00mL faecal coliforms, 0.20.5 mg/L Chlorine residual (dual reticulation applications), and 6 log removal of viruses and protozoa in primary settled wastewater); and
Conventional Activated Sludge Process
• Filtration (Turbidity 500/oile <2 NTU and 1000/oile <5 NTU) . A suggested wastewater treatment process to achieve these objectives is as follows:
Class A+ Effluent
• Conventional activated sludge wastewater treatment plant (1-2 log removal of faecal coliforms, 1-2 log removal of viruses and protozoa, ~50-70 NTU 50%ile) . • Chlorination (3-5 log removal of faecal coliforms, > lmg/L chlorine residual, 0.5-1 log removal of vi ruses and <0.5 log removal of protozoa). • Sand Filtration (3-5 log removal of faecal coliforms, approx. 0.5 log removal of viruses and 0.5-1 log removal of protozoa, <2 NTU 500/oile). • UF (5 log removal of faecal coliforms, 2'.2-4 log removal of viruses and protozoa, <0. 1 NTU 500/oile). Ir is li kely char the above outlined process will achieve compliance with rhe gu idelin es for Class A+ recycled water. However caution must be applied due to limited publicly available operational data and guarantees for virus removal (in particular for the long term performance of UF mem branes). Authority bodies may consider an addirional barrier (such as reverse osmosis, ozonation or UV) is necessary to limit the risk to the community (and of non-compliance to Class A+ recycled water). T ertiary filtration processes such as deep sand bed filtration and cloth disc filtration are suitable pre-treatment processes. Only deep bed sand filtration (SF) has been considered in derail in chis paper. It is important to note that a conventional activated sludge process is considered necessary in combination with the MTP to ach ieve the objectives for the removal of viruses and protozoa.
MTP process unit details A MTP building housing an UF system would typically consist of the following components: • The membrane system (including skids for pressurised ultrafiltration and ranks for immersed ultrafilrrarion);
Membrane Treatment Plant
Figure 1. Recommended process requirements for a Membrane Treatment Plant to achieve C lass A+ effluent.
• Chemical dosing systems (caustic soda, sodium hypochlorire, citric acid, sodium meta bi-sulphite); and
• UF MTP (installation of membrane system to m m-key); • MT P building;
• CIP rank (IUF only). An estimated footp rint requirement fo r the MTP building housing the UF systems are given in Table 2. The footprint does not include the area required for tertiary sand filtration and an activated sludge process.
• All blowers, pumping and piping req uiremen rs;
Table 3 details che estimated footp rint requirements external to the MTP building for tertiary sand filtration, pre and post balance tanks and a pose UF storage rank. The footpr int requirements are the same for IUF and PUF.
Financial analysis A financial analysis was performed with the objective to perform a "like for like" comparison between immersed ulrrafiltration (IUF) and pressurised ultrafiltration (PUF) membrane systems. Budget estimates were developed for MTP systems with the fo llowing output capacities: • 6 ML/D; •
16 ML/D; and
• 24 ML/D. The cost esti mates presented in this section were developed for the purposes of comparing options only, not fo r render purposes. Cost estimates derailed in chis study reflect marker prices in the year 2004/05.
• Blower room;
The capital budget cost estimates accounts fo r the fo llowing: • Sire establishment;
• Control room;
• T ertiary Sand Filtration;
• Pumps and piping;
54 JUNE 2006 Water Journal of the Australian Water Association
• 2x Balance ranks; • l x storage rank; • Chemical dosing/cleaning agents and storage requirements (sodium hypochlorire, citric acid, caustic soda, sodium merabisulphire); • Electrical, instrumentation and control; • Construction and installation; • T esting and commissioning; and • Contingency of 30% (1 0% engineering design and 20% construction). The capital cost estimates are summarised in Table 4.
Operating and maintenance costs The operating and maintenance budget cost estimates account fo r rhe fo llowing: • Power; • Chemicals/Cleaning agents; • Membrane and media replacement; • Maintenance (civil structures, mechanical and electrical); and • Operator input and labour. The operation budget cost estimates are summarised in Table 5.
Operation cost (c/kL) The estimated MTP operation cost (c/kL) was determined by dividing rhe annual production rate by the an nualised operation and maintenance cost in today's money. The results are presented in Table 6.
NPV analysis A 50-year NPV analysis was performed. Civil, mechanical and electrical cost
Table 2. Estimated foo tprint requirements for a UF MTP buildi ng. Membrane System (ML/ d) 6 12 16 24
PUF (m 2)
360 120 m x 18 m) 468 (26 m x 18 m) 624 (26 m x 24 m) 780 (26 m 30 m)
100 (10 m x 10 m) 196 m2 (14 m x 14 m) 256 (16 m x 16 m) 400 (20 m x 20 m)
Table 3. Estimated MTP site footprint requirements for tertia ry sand filtration and balance and storage tanks . Process Unit (ML/ di 6 12 16 24
Tertiary Sand Filtratian (m2)
2x Balance tanks and l x storage tank (m 2)
125 (12.5 m x 10m)
250 m (0.25 ML tanks)
250 125 m x 10 m) 284 127 m x 10.5 m) 500 (25 m x 20 m)
435 10.5 ML tanks) 435 (0.5 ML tanks) 640 (1 .0 ML tanks)
Table 4. TP capital cost estimates. Membrane System (ML/ di
IUF ($ million!
PUF ($ millionl
6.3 9.0 10.9 14.4
Table 5. MTP annualised operation cost estimates ($/annum ). Membrane System (ML/ d)
12 16 24
559,000 655,000 855,000
675,000 1, 132,000 1,436,000 2,048,000
components were assigned replacement periods of 50 years, 15 years and 10 years respecrively. T he resulrs for a 7% discount race are summarised in Table 7. Cost of production
T he cost of production was determi ned by amorrisacion of che capital cost over 25 years (at 7% interest), plus rhe addition of the annual operaring and maintenance cosr in roday's money. T he resul ts are presenred in Table 8 and are displayed graphically in Figure 2. Figure 2 highlighrs rhe cosr effecriveness of immersed systems fo r higher capaciry facilities. T he resul ts agree with comments made by industry and suppliers rhar pressurised systems are cost comperi tive (in Australia) fo r facili ties of capaciry less than 5 ML/d.
Conclusions Ultraftltracion technology provides the platfo rm ro achieve
high quality Class A+ recycled water. To ensure commun ity safery and red uce process risk a "multiple barrier" filtration and disinfection process should be adopted. IUF technology has a higher capital cost co mpared ro PUF technology. T he significan tly lower operation coses (d ue mainly ro lower power co nsumption) provides a distinctive "whole of projecr li fe" (NPV) cosr advantage fo r IUF technology as projecr scale increases. Recent advances in energy savings fo r reverse osmosis rechnology may be transferable ro PUF rechnology, which may result in redu ced coses fo r chis technology in the fu ru re. GHD experience and info rmation provided by suppliers ind icares chat project costs (including operation and maintenance) for PUF systems are lower rhan IUF sysrems fo r flows less than about 5 ML/d.
QUALITY ASSURED ENGINEERED PRODUCTS
Table 6. MTP operating and maintena nce costs. Membrane System (ML/ d)
PUF (c/ kLI
6 12 16
19 13 11
31 26 25 23
Table 7. 50- year NPV analysis results fo r a 7% discount rate. Membrane System (ML/ di 6
12 16 24
IUF ($ millionl
PUF ($ million!
18.0 21.9 24.5 29.8
23 .4 27.0
IUF (c/ kLI
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29.7 34. 3
Table 8. MTP estimated cost of production. Membrane System (ML/di 6 12 16 24
35 31 27
Journal of the Australian Water Association
Results from this study suggest that IUF technology has a distinct cost advantage over PUF technology fo r p rojects greater than 6 ML/d.
:::i' 60 -·r------- - - -- - - - - - - - - - - ~ ~ ~ 50
Dale Young is a process engineer with five
a. 20 -
year's experience in water, wastewater and aquatic science. Email email@example.com. Chris Hertle is a Senior C hemical Engineer involved with design and application of MBR, email C h ris_Herrle@GHD.com.au. Both are with GHD, Brisbane office.
10 0 -j------,-----,-------.-----.....-----1
Output Capacity (MUd)
1-+- IUF -
References Chapman S., Leslie G., (2004), Membrane
Bioreactors (MBR) -An Australian Perspective, AWA March 2001. Freeman S., Leimer G., Milton G., Pressdee J., Veerapaneni S., (2003), Selection and Procurement ofMFIUF Membrane Filtration Equipment, Internacional Desalination Association Conference. Kramer A., Lubben D., Yu Jung Chang, Cline G., (2003), Procurement and Performance Testing Results for the US's Largest Membrane Water Treatment Plant: The Minneapolis Water Works Experience, American Water Works Association Membrane Technology Conference.
Figure 2. Estimated cost o f prod uction for IUF and PUF MTP Facili ties. Hertle C., Crofts J ., Whittle R., Turi P. , Joh nston G. (2001), Picnic Bay Membrane
Bioreactors for Wastewater Treatment at Magnetic Island, Australia, I nrernarional Water Association Conference. Hopkins L., (2002), Reusing Water: The Luggage Point Water Reclamation Plant, Brisbane Water, Brisbane. Lozier J ., Leslie G., Bergman R., Fleischer E., (2003), Developments in M embrane Treatment of Wastewater for Potable and Industrial Reuse, C H 2M H ill , USA
Metcalf and Eddy, (2003) Wastewater
Engineering Treatment and Reuse 4th Edition, McGraw Hill, Sydney. Sakaji R., (2001), California Surface Water Treatment Alternative Technology Demonstration Report, http://www.dhs.ca.gov/ ps/ ddwem/ publications/afrr6_200 l .PDF QLD EPA, (2005), QLD Guidelinesfor the Safi Use of Recycled Water, QLD EPA, Brisbane. QLD EPA (a), (2004), Risk management strategy to meet the Queensland Guidelines for the Safi Use ofRecycled Water, QLD EPA, Brisbane.
Supplier Information (2004)
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56 JUNE 2006
Journa l of the Australian Water Association
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CHARACTERISING WASTEWATER FOR ULTRA FILTRATION A Davey, R Schumann, D Davey Abstract Mem brane technology faces difficult issues in co ntroll ing the rate of organic, colloidal and biological fo uling associated with municipal secondary wastewater. Ir is important to characterise rhe particular wastewater to gain some insight in to the various potential mechanisms char may cause fouli ng . W ithout som e understanding of the feed water chemistry the productivity of membrane systems can be reduced significan tly. Therefore chis paper sets o ut to outline a general approach to testing and measuring parameters relevant to the performance of a membrane fi lter operating on wastewater.
Introduction The p ermeate q uality from membrane treatment is consistently high due to the physical nature of the fil tering process. However, rhe high level of treatment comes at the expense of fou ling due to soluble or colloidal material. Backwashing of the membrane systems rarely removes all of the foulants. Over rime, the foulancs nor removed d uring backwash ing build up to rhe point where they must be removed by chemical cleaning . The protection of receiving waters from poll ution is the p rimary goal fo r municipal Waste Water Treatment Plants (WWTPs). Consequently d ischarged effluent is characterised by measuring nutrient levels (total nitrogen and phosphorous), potential for oxygen depletion (BOD5, COD) and suspended solids (SS). However, while these parameters are important to biological treatment they do nor have as much importance to membrane fi ltration, as they provide insufficient structural derail of the organic com pounds involved. T o properly characterise rhe potential fo r a wastewater to foul a membrane rhe organic material muse be characterised according to size, structure and functionality. Its potential for interaction with the membrane can be determined by molecular weight distribu tion, hydrophobic versus hydrophilic character and charged functio nal group analysis.
A range of soluble organics are present in treated wastewater d ue to their refractory nature during treatment. T hese include synthetic organic compounds resulting from domestic use, and soluble microbial p roducts (SMP) derived from biological treatment of sewage. In addition ocher parameters such as oils, heavy metals, or ocher organic pollutants, which are controlled as part of trade waste programmes, can be present at concen trations although safe for environmental discharge, may be deleterious to the operation of che membrane. T he occurrence and concentratio n of all these compounds are monitored on a voluntary basis if at all.
It is important to analyse the compounds that bond to, and adsorb or precipitate on, the surface of the membrane filter. Consequently, pilot plane trials are usually a necessity to predict operational perfor mance o f full scale membran e fi ltration planes. Although many pilot studies have been performed on rhe characterisatio n of fou ling mechanisms, little is known about methods for proper characterisation of the wastewater which would allow for the foul ing potential of the wastewater to be estimated.
Membrane Composition The influence of mem brane composition on the fo uling race is a critical parameter in mem brane selection. Membrane types include polyerhyl-sulphone (PES), polyvinylidene fluoride (PVDF), polyp ropylene (PE), polyacrylo ni trate (PAN) , with molecular weigh t cut off (MWCO) levels ranging from 150 to 300 kDa for UF membranes d epend ing much on the pore size o f the membrane fi lter. There are p rofound differences in performance, and although surface charge and roughness are accepted as important in
fouling, the crucial characteristic needed to lower membrane fou ling is hydrophilici ty in most cases.
Membrane Fouling Reversible fo uli ng, caused by accumulation of solids on rhe membrane surface is typically remedied by hydraulic backwashing, whereas semi-permanent fouling requires chemical cleaning and limits the viabili ty of the UF due to higher operating coses. Fouling within a V F system fi ltering created wastewater is a complex phenomeno n, mai nly due to the problematic and variable com position of the wastewater. Fouling can be due to biological fl oes formed through conglo meration of micro-organisms, together with a whole range of soluble, insoluble and colloidal compounds, either present in the wastewater before treatment or resulting fro m bacterial action in the treatment process. Fouling is normally defined as two types: â&#x20AC;˘ Surface fo uling (at the macro level); and â&#x20AC;˘ Pore fo ul ing (at the micro level). Su rface fou ling results either fro m a buildup of solids on the surface caused by too high a solids-flu x, thus blinding the pores and reducing the available surface area for filtration, or from precipitation of inorganic salts which form a rigid non porous layer or scale over the surface. Pore fouli ng wh ich occurs at a microscopic level involves blocking of pores via soluble o r colloidal organic matter. Sources include surfactants, slime, extra-cellular polymeric substances (EPS) and SMP produced by biomass and organ ic matter with poor biodegradability. Pore blocking also reduces the available surfa ce area for fi ltration. Adsorptio n onto the membrane proper can lead to an increase in transmembrane pressu re not easily rectified by simple backwashing . Adsorption fouling is usually related to organic materials that are weakly bonded to the membrane (via Van der Waals interactions) and is sometimes referred to as semi-permanent fouli ng. The nature and extent of fo uling is infl uenced by the fo llowing facto rs:
Journal of the Australian Woter Association
JUNE 2006 57
• Hydrophilic/Hydrophobic characteristics of che membrane material; • Pore size; • Membrane flux; • Presence of EPS, SMP and ocher organics; and • Temperacu re and pressure. In the majority of cases che inso luble colloidal matter seems co account for most of the fouling.
Fouled Membrane Autopsies
Figure 1. Low magnification SEM image of inside surface of fou led membrane (left)
Often problematic issues will occur during pilot or fu ll scale operation. A membrane may need co be removed from the plane co identify the particular fou lant causing the issue. An autopsy of fouled membranes can be conducted using a variety of techni ques which include: • Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) co identify changes in the membrane surface and also areas of scale deposi cion; • Attenuated Total Reflectance Fourier T ransform Infrared Spectroscopy (ATRFTIR) co identify fu nctional groups of organic materials depositing on membrane surface; • solvent extraction and Gas Chromatography - Mass Spectrometry (GC-MS) co characterise low molecular weight organic constituents present in a fouled membrane; • solvent extraction and High Pressure Liquid Chromatography - Mass Spectrometry (HPLC-MS) co characterise higher molecular weight organic conscicuents (particularly proteins) present in a fo uled membrane; and • ashing, digestion and elemental analysis to identify inorganic salts present in a fouled membrane. With all these techniques it is advisable co conduce parallel analyses on a virgin membrane co give che appropriate background for comparison with the fou led membrane properties. We have recently carried out such an autopsy on a UF membrane which was used co filter created wastewater and consequently lost a significant amount of flux due co foul ing. The follow ing highlights the information chat can be obtained by application of che various techniques to help identify the causes of fou ling. The reader should note chat the examples discussed may not characterise every plant in practice, or be general to all wastewater sources, but are selected co highlight a range of problems that may be of interest.
a nd virgin membrane (right).
58 JUNE 2006
Figure 2. Hig h magnification SEM image of inside surface of fouled membrane (left) and virgin membrane (rig ht).
shows a higher magnification image of the inside surfaces, indicating chat there has been a build up of material on the inside surface of the fouled membrane.
Scanning Electron Microscope (SEM) For this particular membrane, the SEM images show distinct differences in the appearance of the inside surfaces of the fouled and virgin membranes. Figure l shows a low magnification view of the inside surface, indicating cracking chat occurred during preparation of the fouled membrane for SEM analysis. This cracking is not evident in che virgin membrane, highlighting che brittle nacure of the inside surface of che fouled membrane. Figure 2
FTIR Spectroscopic Analysis FTIR analysis of the fouled UF membrane showed peaks at wave numbers 1650 co 1750 cm- 1 indicating the presence of proteins, fatty acids and lipids (F igure 3). It should be emphasised how important it is to also measure the background spectrum fo r the virgin membrane. In this case chat ~-
,.....,~.......... - - J
' "1"""TT~·· ,
- -- - - - - - - -
r-1 ·r, ' , . TT
r ,-, r-r, ··1-
r ,~ ,_,
Figure 3. FTIR transmission thin film spectra of extracts from a fouled membrane and showing a virgin membrane spectrum overlay in the carboxylate region.
Journal of the Australian Water Association
spectrum clearly shows similar organic substances are present. However, it is the observed increase in peak intensities characteristic of carboxylate groups, that supporrs the view that saturated fatty acids and esters derived from source water are present in the foul ed membrane.
Chro matogram Plots
Other compounds identified in rhe hexane extract of the fou led membrane included herbicides (isopropyl-4chlorophenylcarbamare) and pesticides (2,3,5 ,6-rerrachloro-benzene) , plasticisers (mono-2-ethylhexyladi pace) and additives (benzophenone) which are commo nly found in wastewater. Two common synchecic musk co mpounds (AHTN and HHC B), which are used as fragrances in numerous cleaning and personal care products were also identified. T hese co mpounds are widespread in the environment, and their presence in wastewater is nor unexpected . A bacterial metabolite of criclosan (triclosan methyl ether), which is a preservative used widely in perso nal care produces, was also identified in the hexane extract of the fou led membrane. Triclosan is also common in wastewater. Membrane Feed Water Analysis Once the wastewater source has been determined, a complete and accurate analysis of the wastewater should be made. This analysis should focus on those parameters which have been identified as influential in low pressure membrane fo ul ing. The followi ng discussion highlights recent research on low pressure membrane fouli ng and emphasises chose compounds most associated with loss of flux.
Organic Substances Treated wastewater contains a range of both suspended and dissolved species. Generally a significant proportion of this is
RIC all f i.d ffl •ffl lu1 11 1 10 .,.i.1 • JJt N11u 1 • 4m ·
,oo 5 00
, oo HO
Gas Chromatography - Mass Spectrometry (GC-MS) Figure 4 shows the chromatograms obtained from analysis of hexane extracts of the fo uled UF membrane. T he major compounds identi fied in the hexane extract of the membrane were Cl6 (pal mi tic) and C l 8 (stearic) acids and in the main these acids were present in conjugated form, probably as lipids. Of rhe ocher compounds identi fied in the hexane extract of the fouled membrane, the major group was the C l0-Cl 4 alkyl benzenes. These compounds are the parent compounds used in the manufacture of linear alkyl benzene sulfo nates (LAS), which are used widely in detergent formulations.
uof 50 0
Figure 4. Total ion chromatograms from GC-MS analysis of the hexane extract of foul ed membrane (top), hexane extract + diazomethane (middle) and hexane extract + Meth Prep II (botto m) . Palmitic (C 16) and stearic (C 18) acids are marked . N ote peaks marked with "X" were present in the bla nk extraction and are not extracted fro m th e membranes.
organic material or effluent organic matter (EfOM). EfOM consists of three main groups of compoun ds based on their so urce. T hese include natural organic material (NOM), which is present in potable water which in turn constitutes the majority of wastewater. NOM is the main fo rm of organic carbo n in aquatic systems and is made up of a complex mixtu re of organic macromolecules whose nature can vary depending on the source of the water. le is derived from the degradation of terrestrial and aquatic organisms and generally contai ns a mixture of humic acids, fu lvic acids and hydrophilic acids. The NOM can be fractionated by adsorption using resins and by size using a UF membrane (Chow et al., 2006). It should be noted char che charged, hydrophilic fract ions of NOM are readily removed by chemical coagulation as part of the pretreatment seep for the membrane. A second group of organ ics found in treated wascewacer are materials originating from microorganisms in the treatment process. These include polysaccharides, proteins, am inosugars and fats present as either metabolites or breakdown produces fro m microbial processes. These long chain
fa tty acids, methyl and ethyl esters originati ng from human excreta, soaps and food oils and fats are routinely fo und in domestic wastewater (Paxeus, 1996). The removal efficiency of faery acids is typically 90% compared co 97% for particulate fractions in WWTPs. Fats, oils and grease (FOG) may constitute a significant fractio n of EfOM if che waste water source is largely urban in character. A fu rther sub-division in treatment terms depends on whether manufacturing industries (petroleu m-based oils and grease) or residential and commercial cooking establishments (vegetable and animal sources) are dominant. Such wastes are difficul t for sewage works co deal with, and any residue becomes an issue for a filtration plane (Wacer Resources Resea rch Inscicuce News, 2002). A third class of compounds identified in EfOM are synthetic organic compounds (SOC) resul ting from either domestic or industrial discharges inco the sewer, as well as disinfection byproducts produced as a result of disinfection of either potable or wascewacers. A number of studies have investigated the presence of SOC in created wastewater. For example, Paxeus undertook
Journal af the Australian Water Association
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a comp rehensive study of effluents from wastewater treatment plants in Sweden (Paxeus, 1996). He identified numerous compounds present in low or sub- µg/L concentrations. The study described aromatic hydrocarbons, household related co mpounds (i.e. detergen ts), solvents, plasticisers, preservatives, an tioxidants and clean ing related products in domestic wastewater. These compounds are present in concentrations several orders of magnitude lower than that ofNOM and other microbial degradation products which are usually present in EfOM in mg/L concentrations . Low molecular weight SOC are therefore less likely to be responsible for membrane fo uling than the higher molecular weigh t NOM and b iological macromolecules present in wastewater. Such compounds, if regarded as issue by the membrane manufacturer, can be identified through GC-MS analysis. There has been a limited amount of research reported in the Ii terature on the components present in EfOM responsible for foul ing of low p ressure membranes (Poele et al. 2004, Laabs et al. 2004, Jarusucrhirak et al. 2002). There has been a much more comprehensive study o f the components ofNOM which give rise to memb rane foul ing (Gray and Bolto 2005, Lee et al. 2004, Aouscin et al. 200 l , Carroll et al. 2000, Arny and Cho 1999). Although these studies have been undertaken using a wide variety of water types and using a large array of experimental techniques, there is a generally coherent picture emerging of those components ofEfOM and NOM which are responsible for fouling of low pressure membranes. The majority of the studies on o rganic membrane foulants indicate that the major component of EfOM and, to a lesser exten t NOM, responsible for membrane foul ing is colloidal organic material in the feed water. This material is typically in the size range of 0.4 5 to 0.1 µm and consists of high molecular weight (MW) hydroph ilic substances of protein and polysaccharide origin. These colloidal species form a cake or gel like layer in the surface of the UF membrane resulting in reduced membrane fl ux. Since suspended solids are usually measured as material not passing through a 0.45 µm membrane and these materials are typ ically less than 0.45 µm in size, rneasu remen t of total suspended solid s does not always give a satisfactory indication of rhe potential for membrane fouling. In this case, turbidity may be a b etter measurement to indicate the presence of significant q uantities of colloidal material.
Specific U ltraviolet Absorbance (SUVA) also provides a useful measurement to indicate the propensity of an effluent co fo ul UF membranes. SUVA is defined as absorbance at 254 nm x 100 divided by DOC as mg/L (SUVA= UVA 254/DOC). SUVA values for water sou rces are generally between 1 to 5 rn-1mg-1L. If the SUVA number is less than 2, the UF is u nl ikely ro fo ul, even with a high turbidity. If rhe SUVA number is greater than 4 then the UF is likely to foul and sh ou ld be run at a lower flux. SUVA is generally thought to give a representation of o rganic matter with co njugated double bonds (including aromaticity) in a sample as ir in cludes absorbance at 254 nm. However, in the case o f effl uent samples where there may be a substantial amount of colloidal material in the size range of 100 to 450 nm, the absorb ance of light of similar wavelength (254 nm) may also be accompanied by significant scattering. Thus SUVA may be giving an in direct measurement for the colloidal organic material responsible for much of the UF membran e fouling. This fraction of EfOM can often be reduced th rough fl occulation and adsorption (H.K. Shon et al. 2004) to achieve a lower SUVA number. The second most important class of organ ic material responsible for low pressure membrane fou li ng is the soluble neutral hydrophilic fractio n. In the majority of investigations it is apparent chat this fraction, consisting primarily of polysaccharides, resulcs in reduced membrane flux. Some authors (Lee et al. 2004, Carroll et al. 2000) have suggested char measurement of the hydroph ilic fraction of the o rganic material would be a useful predictor for membrane fou ling. The fact chat small molecular weight, nonionic, hydrophilic NOM is poorly removed by coagulation exacerbates chis problem, as feed water is not readily treated to remove ch is fraction. Several studies have also indicated other species present in the water can influence the degree to which organic matter will fou l membranes Qones and O 'Melia 2001, Aouscin et al. 2001). T hese studies suggest char pH and ion ic strength , and in particular the p resence of divalent cations such as calcium, can influence membrane fou ling by organic matter. It appears that calcium ions are able to promote aggregate formation of dissolved charged organic polymers resulting in increased fouling potential. These results indicate that not only is proper characterisation of organics p resent in the feed water important, but
Journal of the Australian Water Association
that a com prehensive characterisation of inorganic sales should also be undertaken.
Inorganic Substances and Scaling To minimise precip itation and scaling, it is important co check hardness, heavy metals, alkalinity and silica levels in the wastewater. I n a UF system o perating at a h igh recovery, d ue to the presence of nutrients and several ion species, sparingly soluble salts such as CaSiO3, MgSiO 3, Alz(SiO 3h, CaCO3, CaSO4, BaSO4, SrSO4 and Ca3(PO4)z may precipitate on th e reject side of the hollow fibre membranes. If the system is operated at a recovery of 85% then this may resu lt in a concentration of metal salts app roximately 6 times the concentration of che influent. For example, if barium sulfate is p resent in wastewater in large enough concentrations, this can lead to massive precipitation withi n che UF membrane, and possib ly act as a catalyst for calcium and strontium sulfate scaling. As a rule, metal analyses should be conducted to test fo r alumin ium, iron, barium, calcium, magnesiu m, manganese, and strontium, etc. in rh e influent. Acids are normally used to dissolve mineral scaling during chemical cleaning of the membrane system. H owever, interaction of these minerals with fatty acids may create a fou ling layer that subsequen tly reduces the flux of the membrane. It is also often overlooked chat metal carboxylates are not necessarily very solub le, and chat their precipitation can occu r at acid p Hs, adding to the scaling. Solving such problems may require specialised cleaning products. These cleaners employ surfactants to lessen adsorp tion and complexing agents to bring the metal ion into solution, rhe aim being to reverse fo ulant equilibria. To add to the difficulty in solving the problem, the whole process may need a particular pH range for success.
Conclusion In conclusion, membrane productivity can be sign ificantly affected by organic, inorganic and synthetic compou nds present in the wastewater. It is important to analyse rhe size, structure, functionality, quantity and interaction of organic and inorganic compounds chat bond to, and adsorb or precipitate on, the surface of the membrane filte r. SEM, FTIR and GC-MS examples presented illustrate that it is important to analyse the waste water characteristics, and understand fou ling mechanisms behind each measured parameter. Characterisation of rhe wastewater is important co
improving the membrane prod uctivity, and in reducing the need for membrane cleaning, and its impact on plant operation.
The Authors Anthony Davey is Technical Manager IMD, Earth Tech, Melbourne Australia (email@example.com); Russell Schumann is a Senior Research Fellow with Levay & Co Environmental Services in the Ian Wark Research Institute at the Un iversity of South Australia. (Russell.Schumann@ unisa.edu. au); David Davey is an Associate Professor in the School of Pha rmacy and Med ical Sciences at the University of South Australia. (David.Davey@un isa.edu. au)
References Amy G. and C ho J. , ( I 999) , "Inceracrions between natural organ ic matter (NOM) and membranes: Rejection and fou ling", Water Sci. Tech. Vol.40 (9), pp 13 1- 139.
Aousrin, E., Schafer, A. I., Fane, A. G . and Waite, T. D. (2001), "Ultrafiltrat ion of natural organic matter", Separation & Purification Technol. Vols 22-23, pp 63-78. Carroll T ., King S., G ray S .R, Bolco B.A. and Booker N.A (2000), "The fouling of microfiltration membranes by NOM after coagulation treatment", Water Research. Vol.34 (I 1), pp 286 1-2868. C how C., Fabris R. , W ilkinson K., Fitzgerald F. and Drikas M ., (2006) "Characterising NOM ro assess treatabiliry". Water, Vol 33 No2, pp 74-85 Gray S.R, and Bolto B.A. (2005) "Predicting NOM fou ling rates of low pressure memb ranes", Australian Water Conference 2005 . Jarusutth irak, C., Amy, G . and Croue, J-P., (2002) " Fouling characreristics of wastewater effiuenc organic matter (EfOM) isolares o n NF and UF membranes. Desai. Vol 145, pp 247-255 Jones, K. L. and O'Melia, C. R. (200 1). Ulrrafilcration of protein and humic substances: effect of solution chemistry on fouli ng and flux decline. J Membrane Sci. 193, 163- 173. Laabs C., Amy G. and Jekel, M. (200 l ) "Organic colloids and their influence on
low-pressure membrane filtratio n", Water Sci. Technol.. Vol. SO (12), pp 311-3 16. Lee, N-H., A.my, G., C roue, J-P. and Buisson , H. (2004) . " Identification and undersranding of fouling in low-pressure membrane (MF/UF) filtratio n by natural organic matter", Water Research, Vol 38, p p 4511-4523 . Paxeus, N. ( 1996) "Organic pollutants in rhe effiuencs of large wastewater t reatment planes in Sweden ", Water Research., Vol 30, pp 1115-1 122. PoeleS.te, Roorda, J . H . and van der Graaf J.H.J .M., (2004) "Influence of the size of membrane fou lan rs on rhe filte rability of WWTP effiuent", Water Sci Technol. Vol.SO (12), 111 - 118. Sho n, H .K. , Vigneswaran, S., Kim, In S., C ho, J. and Ngo, H. H.,, (2004) "The effect of pretreatment to ultrafiltration of biologically t reated sewage effiuenc: a derailed effluent organic matter (EfOM) characterisation". Water Research, Vol 38, pp 1933- 1939 Water Resources Research Institu te News of t he University of North Caroli n a, ISSN 0549-799X, No.335, 2002.
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Journal of the Australian Water Association
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COMMUNITY-BASED INTEGRATED CATCHMENT MANAGEMENT IN NEW ZEALAND N 8 Edgar Abstract The NZ Landcare Trust, with funding from the New Zealand Ministry for the Environment, undertook a two-year national proj ect aimed at sharing community best practice in integrated catchment management (ICM). In recent years, ICM projects have increased in number in New Zealand , and there is a strong component of community involvement in these projects. Many participants within community-based ICM projects feel that they operate independently of other project initiatives across New Zealand. There is a concern that a lack of communication and exchange of information occurs between individual ICM projects. T he Ministry for the Environment responded to these concerns by funding a project initiative that would enhance the national co-ordination and sharing of information from communitybased projects. This paper focuses on describing the project's objectives and methodology; examining some of the lessons learnt from ICM participants; derailing the communications tools used to enhance national information sharing about ICM; and making recommendations for the national co-ordination of community-based ICM.
Introduction There are a wide range of definitions for Integrated Catchment M anagement (ICM). Essentially, it is based o n a systematic effort to understand the linkages between ecosystems, resources and people (Frieder, 1997). ICM is an ap proach that recogn ises the catchment, watershed or river basin as an appropriate geographic organising unit for managing natural resources in a context that includes social and economic considerations. ICM places a primary emphasis on people and developing a process through wh ich people can develop a vision, agree on shared values and behaviours, make informed decisions and act together to manage che natural resources of their catchment (Murray-Darling Basin Ministerial Council, 2001 ). Ultimately, the
62 JUNE 2006 Water
Lake Brunner catchment, West Coast.
goal ofICM is to find a more effe ctive way to meet the constantly evolving water- related needs of society today.
States, substantial capital and voluntary investments are often being made within these New Zealand catchment proj ects (Bellamy, 1999; Conley and Moote, 2003).
Hearing the stories of real people undertaking real projects and making a real difference on the ground.
The NZ Landcare Trust in conjunction with New Zealand's M inistry for che Environment has now completed a twoyear project entitled: "Integrated catchment management: sharing best practise nationally" . The project's goal was co identify lessons that have been learnt from the implementation of a broad range of local, community-based ICM projects across the country. A key focus of the proj ect was co develop a range of communication cools to ensure the national sharing of information from these proj ects with ICM profession als and participants. The purpose of chis paper is to provide an overview of che outcomes of chis project.
In recent times, che focus on ICM has grown within New Zealand. Many projects have developed at the community level out of concern for the health of parts of the local envi ronment. In particular, concern over the declining water q uality of New Zealand's freshwater ecosystems (Edgar, 1999; Parkyn et al., 2002; Parliamentary Commissioner for the E nvironment, 2004). These community-based ICM projects rend to operate independently of each other and there is a general lack of communication and exchange of information between each project. As in Australia and the United
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The National ICM Project This Ministry for the Environment Sustainable Management Fund proj ect was aimed at sharing comm unity level best practice in integrated catchment management nationally. T he purpose of the
project was to establish a nmvork of ICM practitioners and participants involved at che community level, and co provide opportunities fo r these people to share experiences, tools and approaches ch roughour New Zealand. T he proj ect was fu nded fo r two years - from 1 J u ly 2002 to 30 J une 2004. ICM Project objectives were to: • P rovide a common u nd erstand ing and knowledge base for ICM nationally • Encourage improved networking and cooperative arrangements between I CM programmes and parcicipanrs in N ew Zealand • Identify I CM fram eworks, models and processes, research, monitoring, fundin g so urces and orher tools chat can berrer inform IC M implemen tation • Assist in rhe furth er development o f ICM capabilities ar che community level, particularly, by supporting community lead ers and local co-o rdinators
Project Context and Methodology There are a large number o f ecological restoration projects currently u nderway in New Zealand. To make the cask o f invescigaci ng rhe lesso ns learnt fro m so many IC M p rojects more manageabl e, it was decided to choose projects char mer a range of criteria . Proj ects were chosen char fu lfi lled che following contextual parameters: strong co mmuni ty involvement; a triple bottom line approach (the incorporation of environmental, social and economic dimensions co rhe project); a "mountains co the sea" philosophy (representing a coral ecocone - from the high counrry co rhe lowlands); incorporation of a range of catchment land uses (for exam p le: native ecosystems; plantation forestry; agriculture; periurban and urban development); inclusio n of regionally significant ecosystems within rhe catchments (regional significance was determined by reference to local government resource management policies and plans); interacting and potentially conflicting natural resource use (crossseccoral industries; value conflict; competing resource demand s); and representing a range of catchment scales at which che community were operating (Edgar, 2004). In essence, these contextual p arameters provided a basic typology fo r categorising each community-based p roject. T hese contextual parameters aided in gro uping the catchmen t projects by su ch features as rh e size of che catchments (scaling), p redominant land use (rural o r u rban), the range o f resou rce management issues
Table 1. Lessons fro m community-based ICM projects. • Involve o school w ith the project - for environmental education, o source of labour, and raising the project's profile with parents and the wider commun ity • Seek partnerships wi th local government - for assistance in resourcing the pro ject !e.g . cash support, technical expertise, project advocacy) • Employ a project co-coordinator - for project ma nagement, project communications, group facilitation, preparing funding applications and providing a v isible ' fa ce' for the project • Develop o catchment stra tegy or pion - for identifying long-term visions as well as action steps. Hoving o commun ity-based pion to attach to funding proposals may enha nce funding success. • Multi-task. N ot oil members of the group need to be d irectly engaged in the !often) long-term process of developing catchment plans or strategies. Practical action !e.g. restoration work) on the g round should occur in parallel with this planning effort. • Involve o local polytechnic or university in the pro ject - for lending leg itimacy to restoration actions, undertaking research and advocating for the project • Manage the expectations of community volunteers - match their voluntary labour contributions with some rewords • Involve local landholders with the project - sometimes one-to-one contact is better than trying to get them oil to attend o meeting • Celebrate your ach ievements - work one weekend, on the next take time out to enjoy w hat you are working for
(particularly, land use inten sification versus water quality proceccion), and most importantly, the level of comm unity involvement in che projects. Like all collaborative natural resource management initiatives, catchmen t projects can range signifi cantly in their level of collabo ration or stakeholder involvemenc (M oore and Koontz, 2003) . Some projects are large partnerships of diverse stakeholders represen ting government, industry, landholder, research provid er, indigenous, environmentalist and general public interests. Other projects consist p rimarily of citizens, the class ic grass roo ts, co mm unity-based app roach. Alrernarively, so me p rojects are largely agency-based and driven. Evaluative reviews of collaborative catchment proj ects are beginn ing to support this basic typology: agency-based ; community-based ; o r hybrid/ mixed (Center of W atersh ed Protection , 1998; Edgar, 1999; Moore and Koo ntz 2003 ; C o nley and M oore 2 003). T he age of rhe proj ect is clearly impo rtant in determi ning the mix of participanrs. This national project was focused on identifying rhe lesso ns learnt from active participatio n in ICM initiat ives . In order to do rhis, these iniriarives needed co have operated fo r some rime, co have undertake n some endeavo urs or achievements in order co have some lessons ro offer. T he level of governmental support for community-based resource management is also very importan t in determ ining rhe mix of participants. W here there is political support fo r, o r environmental legislation requiring the active engagement of local government with communi ties, the I CM projects rend to be of rhe hyb rid /mixed type.
Boch rhe New Zealand and A ustralian governments have d evelo ped environmental legislation char requires local , reg io nal and/or state governments co support community-based environmental initiatives - with particular emphasis on using catchments to defi ne this engagement process (Bellamy, 1999; Bellamy et al. , 2001; Bowden et al., 2004). Collaborat ive envi ro nmental management may also be influenced by differen t political contexts across the United States. Moore and Koontz (200 3) suggest that the West has a long history of a strong fed eral role in water resource management and char such federal agencies are usually among th e most active participants in western watershed groups. This co ntrasted with their study in the M idwest (Ohio) were citizens were responsible fo r fo rming rhe largest p roportion of watershed groups. By establish ing a typology of communitybased ICM initiatives in rhis N ew Zealand project, it was possible to identify a manageable number ofI CM projects fo r more derailed case study analysis. Case study analysis utilised a range o f research methods included: one-on-one semi structured interviews with p roject participants; focus group meetings with project participants (including community, local government and research provider participants); interviews wirh ICM project partici pants at their own project meetings; interviews with ICM project participants at each o f che national project's Regional I CM Worksh ops; and participant question naires returned fro m the project's Nation al ICM Confe rence.
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JUNE 2006 63
Lessons Learnt From ICM Projects A key aim of the ICM Project was to identify some of the successful strategies and approaches to communi ty-based catchment projects. D iscussion revealed a wealth o f personal experiences. After all, there is no substitute fo r fi rst- hand experience with environmen tal management. Table l. provides a general summary of these strategies. T h e following quotes typify many IC M participants' observations. Keep it simple. You don't need a lot of science to tell you what trees to plant and where. Just learn from your mistakes, watch the plants, and work out where they thrive best. Its not rocket science.
Don't monitor the scream just for the sake of monitoring. If you don't know where you can get assistance in interprering the data you collecr, or how you can convey rhe infor mation to the public, what good is it? Having local agencies and businesses support your project is a blessing. Work to develop partnerships. Try something novel wi th local politicians and senior local government managers. Maybe a raft trip or a riverside cocktail parry, or get a positive article in to rhe local press. Having scientists o r researchers involved with a project can be very rewarding, you learn all kinds of new in fo rmation you might never have rhoughc of. Bue be clear abou t che relationship and what expectations might be placed on your group. And remember science won't solve all your problems. Don't be put off with your fi rst or second contact wirh local government. Sometimes it rakes a little digging and a little patience to connect with the right person to champion your project in these large organisations.
ICM Project Communications C ommunicati ng the lessons learnt fr om ICM projects, linking IC M participants together around the country, and advising on IC M activities, resou rces and cools was an essential part of the proj ect. T o enhan ce communication and the sharing of experiences, a M icrosoft Access database of contacts was d eveloped - rhe I C M Network. Contacts ranged from p rivate individuals, to fa rmers and landholders. Other contacts represented landcare or community environmen tal groups, central and local government agencies, NGO s, research providers, iwi and industry. A wide variety of communication cools and forums were used to enhance information flows across this network. T able 2 p rovides a gen eral summary of these communication initiatives. The recommendations section of 64 JUNE 2006
Table 2. ICM Project Communications. • Wide distribution of an ICM promotional brochure entitled "The Co-ordinated Approach". This provided on overview of the project and identified opportunities for ICM professionals and practitioners to engage in the project. • The development of a newsletter series - Catchments to Coastlines - that profiled New Zealand ICM projects and personalities, introduced readers to ICM resources, and advised of upcoming ICM workshops and events • The establ ishment of five ICM Regional Working Groups. Working Group members were encouraged to promote the ICM project through their existing networks and to report on the project to their parent organisations, employers and the cammunity/ environmental/landholder groups they represented. • Conducting Regional ICM Workshops (in partnership with the ICM Regional Working Groups) that showcased loca l ICM project initiatives. The workshops incorporated field trips to introduce participants to local projects. • Conducting a Notional ICM Workshop . Commun ity representatives from nationally recogn ised ICM projects were support funded to attend the event and present their projects and lessons learnt to attendees. A CD of the presentations was prepared a nd made widely available. • The establishment of on ICM section on the NZ Landcare Trust's website. Web pages provided information on community-based ICM projects in NZ, the latest in ICM research and tools to support ICM, and lessons learnt from ICM practitioners around the country. http://www.londcore.org.nz/ • Preparing articles on the project and local ICM initiatives for the media (particularly community newspapers) and industry a nd local government newsletters this paper provides more in formation on what I C M N etwork part icipants thought were the most valuable communication tools and forums for chem. Gen erally speaking, the ICM Netwo rk pa rticipants were most suppo rtive of opportunities to engage directly with ICM professionals and community-based I CM project participants at the regional and national IC M workshops.
Recommendations for National Co-ordination of ICM As part of the co mpletion of the two-year ICM Project, rhe N ew Zealand Ministry fo r the Environment requested rhe National Co-ordinator (ICM ) - chis paper's author - to prov ide a fi nal report char would include discussion on what was required to maintain long-term action for national co-ordinatio n of I CM. A number of these recommendations are outlined b elow.
Communications ore Key to Shoring Experiences Feedback from participants involved with chis project has confirmed the value of providing a range of communication opportunities fo r community stakeholders. For exam ple, in reviewing the evaluative feedback fro m participan ts at the National IC M Wo rkshop, 77% of respondents rared the wo rkshop as satisfactory and 86% of the respondents would be interested in attending further workshops on community-based environmental management (Edgar, 2003). T here has been consid erable support for:
Journal of the Australian Water Association
• Co ntin uin g the I CM newsletter series Catchment to Co astlines • Conducting more regional ICM workshops arou nd rh e country to promote action on rhe ground • H osting further N ational ICM W orkshops • Ongo ing updating of the ICM web-sire The regional ICM workshops and rhe National I C M W orksh op were strongly su pported in attendance by community groups and agency staff. The cost of hosting national forums, particularly where funding was used to support the travel of comm un ity group mem bers to attend the fun ction , is h igh. Consequently, a National IC M W orksh op h eld every second year, alternatively in rhe North and South Islands of New Zealand migh t be the most appropriate strategy. National networking opportunities for ICM participan ts are valuable bur might best b e foc used aro und regional communities. Often community p articipants d o nor h ave the rime or inclination to find our what people are d oing in catchments in o ther parts of the country. At rimes the issues are also qui te localised or region-specific. W hat wo rks in one region may be inappropriate fo r transfer and applicatio n to another regio n. Regional workshops also allow more op p ortunity to tailor rhe worksho p to the specifi c n eeds of rhe target audience. T he provision of more regular regional workshops would help to address the gap between providing less frequen t national workshops.
Community Capacity Building in ICM
One of the primary aims of the I CM Project was to furth er develop ICM capabilities at the community level, particularly by supporting comm uni ty leaders and local co-ordinators. The communications ou tpu ts of the ICM Project provided some mechanisms fo r supporting chis capacity build ing withi n local communities . However, participant feedback from the Regio nal ICM Workshops and the National ICM Workshop highlighted the n eed to p rovide more of these learning forums and to p rovide more specialised ICM information and training opportu nities.
App ropriately evaluating community learning oppo rruni ries (with in natural resource management initiatives) is a complex issue bur there is a considerable body of research and k nowledge in chis area char could be accessed (Bellamy et al., 2001; Conley and Moore, 2003). Fostering behavioural change (to more sustainable activities) is a key feature of rhe outcomes of th e Ministry fo r the Environment's Sustainable Management Fund . More attention needs to be focused on developing cri teria or indicators to evaluate rhe human (social) dimensio n of these projects, particularly where the focus is on establishing rhe value of an initiative within communities.
Particularly notable was the overlap between I CM information needs and other knowledge requ irements. For example, participants at rhe national workshop supported fu rther workshops and training on riparian management, pest management and environmental monitoring. There was also a focus on improving skills in social marketing and the need to incorporate science and economic facto rs into chis learning process.
Leadership and Collaboration Leadership and collaboration are clearly pivotal to the fu ture of any national I CM co-ordination initiative. Given the role char catchment management plays in su pporting the principles of both rhe Resource Management Act (1991) and New Zealand's Sustainable D evelopment Agenda there is a need to reconsid er chis country's support for national implementation of ICM. T he role rhe NZ Landcare Trust u ndertook over the two years of chis project was limited by fund ing and staff resources. However, through effective networking many ocher organ isatio ns became involved. Any fu rure initiative would need to be adequately fund ed to gain rhe traction req uired. One possibil ity would be to reformulate the Co-operative Research Centre (CRC) approach being used in New Zealand and Australia to support environmental science provision. The CRC approach involves partnerships between central and regional government, research providers (for example, Crown Research Insrirures, universities and private organisations), industry and communi ty groups. Fo rming a natio nal Co-operative Management Centre (CMC) for ICM in New Zealand would further rhe CRC research focus co include rhe application of catchment research provisio n to sustainable resource management.
Conclusions Despite rhe general acceptance of rhe concept of integrating water and land management, rhe reality of acrual implementation of ICM has been hesitant and unsystematic. I r reflects a si tuatio n in which participants - local government, researchers, and communities - are learning as they proceed. Consequently, there is no obvious correct model to follow. Individuals and agencies are usually cautious with I CM initiatives and fo llow an incremental strategy in which they move forward slowly. U lrimarely, rhe value of sharing knowledge about ICM needs to be recognised for its own sake. There is no substitute for experience when it co mes to managing complex natural and modi fied ecosystems. Trial and error will always be part and parcel of the protection and restoration of our catchments and ware1ways. The opportunity to learn about successful approaches (and fai lures!) is an important way to avoid re-inventing rhe wheel and duplicating effort across catchments and communities. There is nothing mo re motivating and inspiring than hearing the sto ries of real people, undertaking real projects and making a real d iffere nce on the ground.
The Author Dr Nicholas Boyd Edgar is Research M anager, New Zealand Landcare Trust U niversity of Waikato, Hamilton, New Zealand, Email firstname.lastname@example.org
References Bellam y, J. A. ( 1999) Evaluation ofintegrated catchment management in a wet tropical environment: Collected papers of the land and Water Resources Research and Development Corporation. Research and Development Project CTC7. Volu me 1: Synthesis of
Findings (Brisbane, CSIRO Tropical Agricul ture). Bellamy, J. A., Walker, D. H ., McDonald, G. T. & Syme, G. J. (200 I ) A system s approach to the evaluation of natural resource management initiatives, journal of Environmental Management, 63, pp. 407423. Bowden, W. B., Fenemor, A. & Deans, N. (2004) I nregrared water and catchment research for the public good: the Morueka River-Tasman Bay initiative, New Zealand,
International journal of Water Resources Development, 20, pp. 3 11-323. Ce nter for Watershed Protection . (1998) Rapid
watershed planning handbook: A comprehensive guide far managing urbanizing watersheds (Ellicott City: Center for Watershed Protection). Conley, A. & Moore, M.A. (2003) Evaluating collaborative namral resource management, Society and Natural Resources, 16, pp. 371386. Edgar, N. B. (1999) Land use in rhe Taupo catch ment, New Zealand. New Zealand
Journal ofMarine and Freshwater Research, 33, pp. 375 -383 . Edgar, N. B. (2003) Integrated catchment
management national workshop report. Report p repared by the NZ Landcare Trust for the Ministry for the Environ ment, Wellington . Edgar, N. B (2004) Integrated catchment management project final report. Report prepa red by the NZ Landcare Trust for the M inistry for the Environment, Wellingron. Frieder, J. (l 997) Approaching sustainability:
integrated environmental management and New Zealand's Resource Management Act. (Well ington: Ian Axford [New Zealand] Fellowships in Public Policy). Moore, E. A. & Koontz, T. M . (2003) A typology of collaborative watershed groups: Citizen-based, agency-based, and mixed partnerships, Society and Natural Resources, 16, pp. 451-460. Murray-Darl ing Basin Ministerial Council. (2001) Integrated catchment management in
the Murray-Darling Basin 2001 -2010: Delivering a sustainable future. (Canberra: M urray-Darling Basin M inisteria l Council) . Parkes, M. & Panelli, R. (200 1) Participatory action research in a river catchment, Ecosystem Health, 7, pp. 84-106. Parkyn, S., Mat heson, F., Cooke, J. & Quinn, J. (2002) Review ofthe environmental effects of agriculture on freshwaters. Contract Report FGC02206 (H amilton: Narional l nsrimre of Water & Atmospheric Research). Parl iamentary Commissioner for the Environment (2004) Growing far good:
intensive forming, sustainability and New Zealand's environment. (Wellington: Parliamentary Commissioner for th e Environment).
Journal of the Australian Water Association
JUNE 2006 65
URBAN STORMWATER HYDROLOGY FOR AN INLAND CITY S Rahman, D Al Bakri Abstract This paper aims co better understand the effect of scormwacer runoff on the hydrological characteristics and water balance of urban waterways in rural Australia. The study focused on the catchment of Orange, a major rural urban centre in the Central Tablelands of New South Wales (NSW), Australia. The study data co ntributed co the development of the town's stormwater management plan. Six gauging stations were installed co monitor the stream flow in the Blackmans Swamp Creek (BSC) and Ploughmans C reek (PC). T he yearly fl ow from the BSC catchment was 23,840 ML. Of this, urban scormwater runoff contributed 69%, treated STP effluent accounted for 23% and the runoff from the rural area upstream of the catchment provided 8%. The annual fl ow from the PC catchment was 6,460 ML; 85% of which was derived from the urbanised carchment and 15% from the upstream rural area of the catchment. The volumetric runoff coefficients were 0.27 for rural areas and 0.58 for urban areas.
A significant contrast to similar-sized coastal catchments. Comparing the study results with those of urban catchments in the rural coastal region of Eastern Australia showed a significant contrast. The water cycle balance and water quality of waterways in the upland urban catchments were mainly driven by urban scormwacer runoff whereas the urban waterways in coastal rural region were mainly related co rural ru noff. This d ifference is mainly due the position of the urban areas in the catchments. Effects of urban areas tend co be more pronounced in the upstream catchments than in che downstream catchments.
Scream flow is a critical determinant of water quality as ic influences the
Rifle Rangt Cruk Sub-catchment
Eute,n Channel Sub-criohmant Upper Bl.lokm1ns: Swamp C rHk Suh-oi1tchment Upp tr Ploughm1ns Cruk Sub-utchmult Lower Ploughmus Cruk Sub -catchment
Figure 1. Ora nge urban catchments and monitoring sites.
66 JUNE 2006
EEI) Lowu Blukm1ns Sw1mpCruk Subâ&#x20AC;˘ OA1lchmant
This paper aims co quantify scream flow and assess spatial and temporal variation of
management, water balance, urban waterways, rural catchments.
Rud .& 1
scormwater runoff in che urban catchment of Orange, a major rural centre in che Central Tablelands of NSW, Australia. T he study d ata provided crucial input co determine the impact of scormwater runoff on the hydrology, water cycle balance and water quality in the urban waterways of rural catchments (Rahman and Al Bakri 200 1).
Key words: Stormwater, runoff,
Journal of the Australian Water Association
concentration and loading of pollutants entering from point and d iffuses sources. During periods of low flow, ground water inflows, effluent discharges, and illegal d ischarges can dominate water quality. But during high flow periods, agricultural and urban runoff has the dominant effect on water q uality. The surface runoff from a catchment depends on facto rs such as volume, intensity and d uration of rainfall, as well as d uration of the preceding dry
period. Apart from the above rainfall characteristics, there are a number of sire-specific factors such as so il types, topography, vegetation and the size of catchment wh ich have direct bearings on runoff volume (Pravoshinsky and Gacillo 1969) . Urbanisation has a profound impact on the quantity of stormwacer runoff and subsequencly scream flow (Neller 1982) . The degree of urbanisation, amount of the impervious area and nature of the drainage system influence runoff generation in u rban areas (D ebo and Resse 1995). Fleming and Daniell (l 997) reported char stormwarer volumes withi n urban areas d epend also on how they are hydraulically connected to the scream. Normally, channels, gutters, storm sewers, and drains are built in urban areas to p rovide a better hydraulic effi ciency. Braune and Wood (1999) reported that the peak flow rare from a developed area could be three rimes higher than from a natural area. In a natural catchment, vegetation and irregular surfaces usually slow surface runoff (Neller 1982). T herefore, runoff generated from a storm in an urban area is far greater than it is on a rural area. Removal of trees and vegetation fro m natural land decreases evaporranspirarion and the interception of rainfall. Usually in urban catchments, rhe creeks will have minimal base fl ow bu r will have a greater volume of runoff. Generally, a rural hydrograph is slower to reach rhe peak of disch arge than an urban catchment hyd rograph, as surface runoff from a rural catch ment starts later and fl ows more slowly because ofvegerario n (DLWC 1998). The runoff coefficient, which is a measure of sire response to rainfall events, is used in estimating flow rares. Ir represents the ratio of vol ume of surface runoff to the total rainfall volume (Schueler 1987) . The process of runoff generation continues as long as the rainfall in tensity exceed s the actual infil tration capacity of the so il bur it stops as che rare of rainfall drops below rhe actual race of infiltration. As the physical condi tions of every catchment are d ifferent, the runoff coefficient shows spatial and temporal variation within and among catchments. In rural catchments, where none or o nly small parts of the area are impervious, the runoff coeffi cient is lower than in urbanised catchments (Pilgrim 1987).
of chis study, the BSC catchment was divided into four su bcarchments. The U pper Blackmans Swamp Creek subcatchment is dominated by agricultu ral and rural land use, Rifle Ran ge C reek subcarchmenr which includes rhe central business d istrict (CBD) and is dominated by business and commercial land use, East Orange Channel subcatchmenr which is dominated by industrial and some residential land uses, and the Lower Blackmans Swamp Creek subcarchment where rural residential land use prevails. Ploughmans C reek drains the northwest and western sides of Orange, wh ich represent about 40% of the urban area. This creek is an unlined channel and fl ows north into the Bell Rive r. This catchment is subdivided into the upper (rural) and the lower (rural residential) Ploughmans Creek su bcarchments. Orange has a cold temperate climate; the coldest months are between May and September with an average temperature of 7°C. The weather turns into a pleasantly warm sum mer between October and April with an average temperature of l6°C. Longterm rain fa ll d ata (Orange City Council 1996) indicate a relatively high level of p recipitation, com pared with other inland centres, with a mean rare of 875mm. On average, rain falls o n 128 days per year. T he colder months, May to October, are marginally wetter rhan the warmer mo nths. T h e an nual evapo ration data for the study area was obtained from the Bu reau of Meteorology for Orange Agricultu ral Institute (Station no . 063254). Although rhe rainfall is distributed relatively even ly throughout the year, evaporation shows a distinct summer peak and wi nter low. When co mparing mean annual evap oration and average annual rai nfall, a moistu re d eficit (net difference between evaporation and rainfall) was evident during the warm months. During rhe colder and
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Orange Urban Catchment Orange is sicuared approximately 250 km west of Syd ney in the Central Tablelands of New So uth Wales . T he city encompasses several suburbs at the eastern foot of M ount Canobolas with a population of about 40,00 0 . The total area of the Orange urban catch ment is 58 km 2 , most of which is classified as rural land (Figure I ). The urbanised pare of the catchment, which is the focus of chis study, is approximately 22 krn 2 (Figure 1). Orange has an extensive srormwacer drainage system, which is designed to co llect and carry sro rmwacer fro m the residen rial, commercial, business and industrial areas to the natural wace,ways, namely the Blackmans Swamp C reek (BSC) and Ploughmans Creek (PC) . These two creeks are part of the headwater creek system o f the Macquarie River, a main tributary o f the Murray- Darling River system. The Blackmans Swamp C reek picks up treated effl uent from the Sewage Treatment Plant (STP) before it joi ns Summer Hill Creek at C lifton Grove. T he lower reach of rhe BSC, wh ich is contained in a narrow bur well-defi ned chan nel wi th a flat wide flood plain , d rains the majority of the central, eastern and northern pares of the city. Ir has two tributaries within the urban area: Rifle Range C reek and East Orange Channel. Rifle Range Creek fl ows north for about 3km before its natural stare is modified by a 3 x 1200-mm culvert at Gardiner Road. The East O range C hannel flows north to join the BSC via a combination of open d rains and closed conduits. T here is very little of this creek remaining in its natural stare (Sinclair Knight and Partners 1980). For the purpose
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Journal of the Australian Water Association
JUNE 2006 67
technical features refereed paper
slightly wetter period (May-October), the evaporation rate was usually lower than rainfall. d epth, which indicates the existence of soil saturation and h igh runoff.
Table 1. Flow data of the Blackman s Swamp Creek (BSC). Period
Rifle Range Creek
East Orange Channel
Total BSC catchment
1998-1999 (ML) 1999-2000 (ML) Average flow (ML/yr) Contribution (%)
5174 5809 5492 23
2877 3474 3176 13
1606 2038 1822 8
22253 25427 23840
T he stormwater runoff was monitored from N ovember 1998 to October 2000 at the fo llowing 6 gauging sites: Site 1: Lower Blackmans Swamp Creek Ophir Road (rural residential area)
Site 2: Rifl e Range Creek - Dalton Street Railway Bridge (CBD)
Site 3: East O range C hannel - William Street Bridge (industrial area)
Sire 4: Upper Blackmans Swamp Creek Woodward Street Bridge (ru ral area) Sire 5: Lower Ploughmans Creek T homson Road Bridge (rural residential area)
£ ~ 0
Stream Flow and Runoff Coefficient
Blackmans Swamp Creek Catchment Approximately 50 % of rhe land area of the
Site 6: Upper Ploughmans C reek Ploughmans Lane and Forbes Road intersection (rural area). Water discharged through monitoring Sire 1 represents the total flow of the Blackmans Swamp Creek catchment, which includes the STP effluent and stormwater runoff derived fro m rural and urban pares of the catch ment. A PYGMY current merer model 'OSS-PCI' was used to measure stream velocity and establish a rating curve for each of the six sires. Discharges were calculated according to the area - velocity method by multiplying the mean velocity by the cross sectional area of the flow (O'Loughlin 1994). The HYDSYS® database package (Hydsys Pry Ltd. 1998) was employed to analyse the instantaneous flow data and to construct the rating curves and raring discharge rabies, hydrographs and catchment runoff coefficients. Continuous disch arges were measured at Sires l, 2, 3 and 5 using IS C O 4230 water dep threcorders, which measured water depth by means of bubbler pressure transducers. IHAC RES®, a catch ment scale rainfallstream flow model (Littlewood et al. 2000), was used to simulate stream flow in periods when flow measurements were nor available and to develop a dynamic relationship between rainfall and stream fl ow of rhe catchment. IHACRES® simulation rakes into consideration the insta ntaneous stream flow measuremen ts and rainfall data (Littlewood et al. 2000). T he runoff coefficient fo r the catchment was calculated by dividing the annual stormwater volume over annual rainfall volume (Chiew et al. 1997).
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-- - "' "'
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0 0 0
0 0 0
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Figure 2. Daily hydrograph of the Blackmans Swamp Creek (Site l ).
BSC catchment (34 km 2) is impervious because it is intensively urban ised. The coral flow discharged rhrough Sire (1) was 22,253 ML during November 1998 October 1999 and 25 ,427 ML for the period N ovember 1999 - October 2000 (Table 1). The average fl ow of the BSC over the two years of study was 23,840 M L. Of this, stormwarer runoff contributed 77% and rh e STP effluent provided the remainder (23%). The stormwarer flow
varied from as low as 309 ML in February 1999, when rhe rainfall was 12 mm, to 3848 ML in October, when rhe rainfall was 224 mm. Variabili ty of stormwarer flow , which is refl ected in the daily runoff hydrograph (Figure 2), is closely related to variability in weather and it is rainfall dependent (Figure 3). In co n trast to stormwarer flow, STP effluent discharge was less variable over time (Figure 3) . Only small increases in
3XJ0 ::i: ~ 3000
"' l XJ0
1000 XJ0 0
°'~ °' °'~ z ....,
°' °'0.. °' °' °' °'::,',., "ii ., °'~ ...., °' z ~ V"I
Stonmw.te r Flow -
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Figure 3. Month ly stormwater flow and STP effluent discharged through Site (l ).
68 JUNE 2006 water Journal of the Australian Water Association
effl uent volu me were recorded during extended or heavy storm events. The 12% increase in volume of the STP effluent in the second year was largely due co overflow from the stormwater system into the sewage system during high rainfall events. The lowest effluent discharge (274 ML) was in February 1999 and highest effluent vol ume (679 ML) was in October 1999, the weccest month of the srudy period. Despite this temporal pattern, the influence of the STP effl uent on the catchment flow was more critical during the drier months of the year (F igure 2). For instance, the monthly efflu ent discharge in February 1999 was close co 77% of the coral catchment flow due to the low rainfall in that month. In contrast, the effluent discharge during the weccest month October 1999, represented only 15% of the catchment flow. Exclud ing the ST P efflu ent, 74% of the total stream flow in the BSC catch ment over the rwo years of srudy was contributed by storm events that occurred during 27% of the study period. T he base flow, which is derived from groundwater, wash ing vehicles, irrigation of lawns and gardens, and wa ter from street cleaning, only contributed 26% of the total flow during the study period. A similar paccern of contribution was also evident in all BSC subcatchments (Table 1). T he volumetric runoff coefficient for 1998 -1 999 was 0.53. In the second year, the runoff coefficien t was fo und to be 6% more than in the first year due to higher rainfall in the seco nd yea r. On average, the overall volumetric runoff coefficient was 0.56 in the BSC . catchment during the study period. Lower BSC (Guaging Site 1): This subcatchment covers an area of 10.7 km2 of which almost 40% is im pervious, as it is dominated by newly developed residential area and semi rural area. The total flow discharged at chis site was 5,73 1 ML during first year and 6,278 ML in the second (Table 1). On average, chis subcacchment contributed approximately 25% of the total flow discharged from the BSC. The volumetric runoff coefficient fo r chis subcacch ment was 0.57. Rifle Range Creek (Gauging Site 2) : The Rifle Range Creek subcatchment covers an area of 10.3 km 2 and is highly urba nised; dominated by the CB D. Approximately 75% of th is subcacchment is impervious. On average, chis subcacchment contributed approximately 3 1% of the total flow discharged from the BSC catchment, representing the highest contributor among all the subcacchments. The scormwacer flow varied from 225 ML in May 1999, when the monthly rainfall was 30 mm, to as high as 2173 ML in October 1999, when the
800 700 600 :J' 500
6 ~ 0
400 300 200 100 0 00
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Figure_4. Dai ly hyd rograph of the Plough mans C reek (PC). rainfall was 224 mm. It was also noticed that the creek was always running at Site (2), al though there was no flow at Site (4), particularly during prolonged dry periods. The volumetric ru noff coefficient of the Rifle Range Creek subcatchmen t was 0.71 in the fi rsc year and O. 74 in the second year with an average of0.73. East Orange Channel (Gauging Site 3): T his subcacchment (7. 13 km 2) is located approximately one kilometre east of the C BD. T he land use is mixed industrial, commercial and residential with impervious area representing 50% of the subcacchment. The drainage consists of concrete and natural waterways, which was always running, although during prolonged dry periods very little flow was observed. The average annual flow discharged through Site (3) supplied 13% of the total runoff of the BSC catch men t (Table 1). T he volumetric
runoff coefficient averaged 0.45 for the 2year study. Upper Blackmans Swamp Creek (Gauging Site 4): The Upper BSC subcacchment (6 km 2) is rural in nature, with only 20% of its area being impervious. As this was an ungauged catchment, flow characteristics were estimated from a rating curve developed on the basis of caki ng several instantaneous flow measurements using a current meter. The instan taneous flow data were then calibrated against concurrent discharges of the nearby gauged Site 1 on the same creek using the fo llowing regression model:
Site (4) = 0. 112 * Site (1)-2.1 142 R2 = 0.9687 The average annual flow from chis subcatchment (S ite 4) was 1,822 ML, which represented only 8% of the total BSC
1200 150 E
200 0 00
°'> 0 z
°' °'1'l ~
°' °'.,b. V,
°' °'> 0 z
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Figure 5. Monthly flow in the Ploughmans Creek (PC) . Journal of the Australian Water Association
JUNE 2006 69
flow (Table 1). D ue to the rural nature o f the catch ment rhere was no flow during most of February 1999. Base fl ow was observed only shorcly after heavy rainfall periods. T he estimated volumetric runoff coefficient was O. 31 for che study period. This was the lowest runoff coefficient amongst the fou r BS C subcacch ments.
Ploughmans Creek Catchment (Gauging Sites l & 2) T he Ploughmans Creek (PC) drains che northwest and western sides of O range, which represents about 40% (24km 2) of che urban catchmen t area. This creek is an unlined channel and flows north into the Bell River. T he catchment is dominated by rural land use and to a lesser extent by residential area, with only 20% of its area is impervious. Yariabiliry in the weather during the study period had a consid erable effect o n flow , as reflected in che daily runoff hydrograph (Figure 4) and monthly runoff (Figure 5). In summer and au tum n months, chis catchm ent shows little or no flow, particularly in the Upper Ploughmans Creek, due co che low rainfall and high evaporation. The total flow discharged through Site (5) was 5,854 ML during first year and 7,063 ML in the second year. The average annual fl ow over the two years of study was 6 ,460 ML (Table 3). Approximately 80% of the runoff was contributed by storm events chat occurred during 25% of che study period. The average runoff coefficient over che two years was 0.28.
Discussion The average annual scream flow discharged from O range urban catchment over the cwo years of che study was 30,300 ML. Stream flow exhibited marked temporal and spatial variation over the study period. Due co lower rainfall in 1999 the scream flow was higher in 2000 than in 1999. T he stormwacer runoff was moderately higher during the colder and wetter months in winter and early spring of both years. T he flow in the urban creeks was dominated by storm events. The storm flow, which o ccurred only 20% of the time, contributed approximately 80% of the total annual flow. It was also evident chat runoff hydrographs followed rainfall temporal patterns closely. T he storm hydrographs clearly showed chat di fferent rainfall intensities produced different peak flows. H ydrographs from less incensiry rainfall events were much fla tter than chose associated with h igh intensiry rainfall episodes. Daily flow records show char runoff from large storm events continued well into the following day due to either prolonged or mulciple episodes of rainfall over an extended time. 70 JUNE 2006
Table 2. Flow data of the Ploughmans Creek (PC). Period
Lower PC subcatchment
Upper PC subcatchment
Totol PC catchment
1998-1999 (ML) 1999-2000 (ML) Average flow (ML/yr) Contribution (%)
857 1047 952 15
7063 6459 100
Table 3. Contributions of different subcatchments and the STP effluent to stream flow. Period
1998-99 (%) 1999-00 (%) Average(%)
Blackmans Swamp Creek Site 3 Site 2
26 25 25
31 31 31
Mose of the flow (79%) was discharged through the BSC catchment, whereas che less in tensively urbanised PC catchment contributed the remaining 21 % . Within che BSC catchment, The Rifle Range Creek was the highest contributor to the fl ow (3 1%) whereas the rural area (Upper BSC) was the least contributor (8%) . T he STP co ntributed 23% of che flow and the Lower BSC subcacchment and East Orange Channel contributed 25% and 13% of the flow respectively. In the PC catchment, the rural area (Up per Ploughmans Creek) provided 15% of che total flow in the C reek and che urbanised pare of the catchment (Lower Ploughmans Creek) contributed the remaining 85% (Table 3) . The impervious areas generated significan rly more runoff and showed quicker flow respo nses than che rural areas of the catchment. In wee weather the contribution from che STP effluent was substantially larger than in d ry periods due co excessive inflow and infil tration of rainwater into the sewerage system. The runoff from che urban area was almost three times chat from the rural area. Braune and Wood (1999) scared chat peak flow race in urban areas could be fo u r times as high as chat of rural areas. Codner, Laurenson and Mein (1988) showed char rural area runoff is one sixth of urban area's runoff. Volumetric runoff coefficients varied from 0.26 (rural subcacchmenc) co as h igh as 0.72 (CBD and resid ential subcacchment). This is consistent with find ings from ocher catchmen cs that have similar hydrometeorological and urban conditions. For example, NSW-EPA (1998) reported chat the runoff coefficient fo r rural catchments ranged from 0.02 co 0.23, whereas coefficients fo r urban catchments ranged from 0.41 co 0.80. It has reported chat in Fairfield, Sydney where urban land use was 85%, the volumetric runoff co effi cient was 0.80. On the ocher hand, Yarralumla Creek in Canberra, where u rban land use is 60%,
Journal of the Australian Water Association
13 14 13
7 8 8
Ploughmans Creek Site 6 Site 5
85 85 85
15 15 15
the runoff coefficient was 0.35. Nichols and Shore (1995) observed chat 0.73 or even higher runoff coefficient could be generated from an average annual rainfall. A study conducted by Lyall and Macoun Consulting Engineers (1998) in the Orange area estimated chat where the main land use is rural, the volumetric runoff coefficient is 0.26. US-EPA (1983) noted runoff coefficients co fall within a range of 0.2 to 0.6 for urban areas. Comparing Orange urban catchment, which is situated in the NSW Central T ablelands, with coastal catchments of similar nature and population revealed an interesting co ntrast. In che Orange catchment, the stormwacer runoff from the urbanised pare of che catchment was the d ominant source (~ 70 %), whereas che upstream rural runoff contributed <1 0 % of the flow in the urban creeks. In contrast, the flow in the urban creeks in the coastal catchments of C larence Estuary and Brunswick River was quite the reverse. The contribution of the rural runoff accounted fo r up to 90 % of the fl ow in the u rban creeks, whereas the urban stormwacer runoff contributed between 10-15% of the fl ow (Eyre 1997, 1998, Mashiah 2002). This considerable difference is attributed largely co che face chat the Orange catch ment is situated in the headwaters of the Macquarie River system and as such the rural runoff en tering the urban catchment was limited. The coastal catchments, o n che ocher hand, represent the lower end of their river systems and chus the rural input co the urban waterways is substantially more than chose in che upland catchments. Based on chis comparison, it can be argued chat the relative impact, per capita, of urban scormwacer runoff o n the water cycle balance and water quality may vary according co the position of the urban area in the catchment.
technical features refereed paper
To mitigate the flooding propensity and to reduce the impact of major sto rm events in the urban area of Orange rhe followi ng actions are recommended: • Co nstructing detention basins upstream of the CBD to reduce localised flooding by reducing flow from existing and newly developed urban areas. • Improving rhe downstream channel capacity to reduce the ponding of major flows upstrea m of these structures. • Establishing several artificial wetlands to improve water quality by red uci ng suspended solids, turbidity and nutrients. • Install ing energy dissipaters such as gabions, riprap and co ncrete blocks at outlets of stormwarer pipes and culverts discharging into creeks to reduce the erosion of the streambank and im prove downstream water quality (H unt 1992).
Conclusions The presence of impervious areas, which are mainly co ncentrated in the middle of the Blackmans Swam p C reek catchment, was fou nd to infl uence much of rhe runoff volume and peak discharges, and was also responsible fo r rapid increases in scream flow with rai nfall events. The runoff volume was also influenced by loss of vegetatio n coverage and storage capacity T he increased volume entering waterways during storm events causes scouring in both Blackmans Swamp Creek and Plough mans C reek. Pans of the Orange catchment are prone to overland floodi ng due to poor drai nage condition and low capacity of the existing stormwarer in frastructu re. The stormwater system, much of wh ich is 50 years old, can carry only a 1 in 20 yea rflood annual accedence exceedence probability (AEP) event. This means that sto rms in excess of the system capacity will travel overland along the path of least resistance. This leads to localised flooding of roads and properties. Open space areas adjacent to rhe Blackmans Swamp Creek from ch e source to the junction of the Rifl e Range Creek near Anso n Street, che area between Lords Place and Peisley Street, the Blackmans Swamp C reek downstream of che Orange-Dubbo railway line, area downstream of Bath urst Road along che Ease Orange Channel and the PC downstream of Forbes Road are likely to be subject co flood ing as a result of one in 100 year storm events. Actions to mitigate the flooding caused by urban ru noff have been proposed.
Acknowledgments T he authors would like to acknowledge and express their appreciation to NSW
Environmental Protection Authority, Orange City Council and T he University of Sydney for providing necessary fundi ng and facilities to undertake che research. A special note of thanks is given for the expert advice and worthy suggestions received from Dr G O'Lo ughl in, Anstad Pry Led, Sydney, Australia and Dr L Bowling, NSW Department oflnfrasrruccure, Planning and Natu ral Resources, Parramacra Office, Australia.
The Authors Sadequr Rahman has a PhD in Road Construction and Maintenance and an MPhil. in Stormwarer Management. He worked as a Pavement Engineer in Orange C ity Council in NSW. Currently Dr Rah man is with Main Roads WA as a Project/Contract Manager. Dr Al Bakri is sen ior lecturer in environmental and water management, Faculty of Agricul ture, Food & Natural Resources, at rhe University of Sydney, email: email@example.com)
References Braune MJ , Wood A ( 1999) Best Management Pract ices Applied to Urban Runoff Q uan tity and Quality Control, Water Science Technology, vol. 39, (12), I 17-121. Ch iew F H S, Mudgway L B, Duncan H P, M cMahon TA (1997) Urban Stormwater Pollution, Industry Report, Report 97/5, Cooperative Research Centre fo r Catchment Hyd rology, C layton, Victoria. Codner G P, Laure nson, E M , Mein R G ( 1988) Hydrologic Effects of Urbanisation: A Case Study, H ydrology and Water Resources Sym posium 1998, ANU, 1-3 February, Canberra, pp. 20 1-205. Debo TN, Reese A J ( 1995) Mrmicipaf Storm Water Manngement, Lewis Publishers, London . D LWC ( 1998) The Constructed Wetlands Mnn unl. Department of Land and Water Conservation (D LWC), Sydney, NSW. Eyre B ( 1997) Contribution ofSewage Effluent to the Brunswick Estut11y Nutrient Budget, Report for Byron Sh ire Council, November 1997. Eyre B (1 998) Wnter Qunlity in the Clnrence
Estuary, in Clnrence River tstuary Process Study (Appendix C), Manly Hydraulic Laboratory D raft Report MHL 971, Sydney. Fleming N, D an iell T ( 1997) A Strategic
Perspective on Stormwnter Management for the Northern Adelaide Plains, Seminar proceedings "Stormwater in the next millennium: exportable innovat ions in stormwater management", Hydrological Society of South Aust ralia, University of South Australia, Narional W ater Week 23/ 10/97, Adelaide. Hunr J S ( 1992) Urban Erosion and Sediment Control, NSW Department of Conservarion and Land Management, Sydney. H YDSYS Pty Ltd ( 1998) HYDSYS/TS, Software suite for acquiring, managing vast collections of rime series data. Littlewood I G, Down K, Parker J R, Post DA (2000) The PC version of IHACRES for
catchment-scale rainfall - stream flow modelling, Version 1.0. Lyall and Macoun Consul ring Engineers ( 1998)
Constructed Wetland at Ploughmans Lane, Ornnge, Investigation and Concept Design Report, Lyall and Macoun Consul ring Engineers, Chatswood, Sydney. Mashiah G (2002) Rural Pollution l oads in Urban Stormwater Environments, Proceedings of the 6th Regional Conference on Urban Stormwater Exploding The MythsSrormwater Driving The Water Cycle Balance, Stormwater Indusrry Association, 23-24 April, Orange NSW (7 pages). Neller R ( 1982) Urbanisation and stream
channels' in Man nnd the Austmlian Environment, in W . Hanley and M. Cooper (eds), McGraw-Hill, Sydney, 24-36. Nichols PS, Shorr SA ( 1995) Stormwnter Qunlity Management on Trial, in the Second International Symposium on Urban Stormwater Management 1995 Integrated Management of Urban Environments, Melbourne, 11- 13 July, Institution of Engi neers, Australia, C anberra, 55-60. NSW-EPA ( 1997) Stnte ofthe Environment, NSW Environment Protect ion Authority, Chatswood, Sydney. NSW-EPA ( 1998) Managing Urbt111 Stormwater: Council hnndbook, NSW Environment Protection Authority, C hatswood, Sydney. O'Lough lin G ( 1994) Notes 011 Engineering Hydrology, University o f Technology, Sydney. Orange City Council (l 996) State ofthe Enviro11ment Report 1995-96, Orange, Australia. Orange Ciry Council ( 1999) State ofthe Environment Report 1998-99, O range, Australia. Pilgrim DH (ed.) ( 1987) Australian Rainfall
and Runoff- A Guide to Flood Estimntion, Volume no. I, The Institution of Engineers, Canberra, A ust ralia. Pravoshinsky NA, Catillo P D ( 1969)
Determination ofthe Pollution Effect of Surface Runoff, rhe 4th Inte rnational Conference on the Advances in Water Poll ution Research, 187- 195. Rahman S, Al Bakri D (200 l) Impact ofpoint
sources and diffi1se sources on stormwater quality in Orange, NSW, Australia, Water Resources Management, edi ted by CA Blebbier, P.Anagnostopoulos, K Katsifarakis, A H Cheng, WIT press, Southampton, Boston, 195-204. Schueler T R (1987) Controlling Urban Runoff
A prnctical Manual for Plnnning and Designing Urban BMP's, Deparrment of Environmental Programs, Metropolitan Washington Council of Governments, Washington D .C. Sinclair Knight and Partners (1980) Orange Drainage Study, Orange C ity Council and Bathu rst Orange Development Corporation, Sydney. US-EPA (1983) Methods for Chemical Annlysis of Water and Wastes, EPA/600/4-79-020, revised March 1983, Environmental Monitoring Systems Support Laboratory Office of Research and Development, US Environmental Protect ion Agency, Cincinnati, Oh io, USA.
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JUNE 2006 71
EVALUATING MODELLING SOFTWARE: THE HIDDEN FEATURES P Banfield Introduction There is general agreement that the costs/ben efit balance of hyd raulic modelling is now heavily in its favour. T he massive advances in both speed of b uild and ease of use over recent years make modelling the best approach to a far greater range of issues rhan was the case even a few years ago. H owever, as many users know as they cry to select modelli ng sofrware, comparative evaluations of sofrware packages are difficult. T here are several reasons for chis, which are perhaps inevitable given the breadth and depth of function with in modern modell ing sofrware, including: • there are very few people with equally detailed knowledge and experience of several products that is necessary for true comparison; • it is almost impossible to devise an evaluation harness, in formal or forma l, that does not contain a built-in bias cowards one product or another; • geography also plays a part in evaluation, with some prod ucts looking good for a specific lo cation but not being as applicable elsewh ere; • the usual binary tick or cross approach to a feature list for software selection is an oversimplification of how well each produce meets each criterion - scales of 1 to 5 are more appropriate; • che weigh tings that should be applied to the values in a rick list vary from customer to customer, and even from proj ect to project, accord ing to their specific needs, and identifying these weightings requires extensive experience of the use of modelling; • produce com parison is a lengthy and therefore expensive process, so any published results are likely to have a commercial agenda behind chem rather than being a truly independent approach; • one of the most important attrib utes of any sofrware product is ics usab ility, and ch is is che most su bjective and therefore the hardest to quantify. The detailed technical functional ity of different packages has been extensively covered in various publications. Taken together, these provide a fair view of the engineering functionality of produces -
whether or not they use rhe St Venant equations, and if so, how they solve rhem, whether the modelling is dynamic, uses variable timesceps, can represent Real Time Controls, and similar important fun ctionality. Clearly any modelling package muse meet a certain level of calculation accuracy to p roduce valid resu lts on which capital and operational decisions can be soundly based. In addition, depending on che complexity of che system it is required co model, ic must have a certai n bread ch of feacures. Bur producing accurate results th rough a fast and stable simulation engine is only pare of che story for hydraulic modelling packages, a necessary bur not suffi cient condition. A number of ocher features chat lie outside this core technical/math ematical fu nctionality are just as important, but are freque n tly not to the fo re in the evaluation process. Hard to measure in many cases, they dictate the usability, productivity, and ulcimately the cost/benefit balance of modelli ng.
It is worth putting in the effort to determine the true cost/benefit. Productivity Features The prod uct ivity of th e modeller or modelling ream is the key determinant of the cost of modelling: good modelling software contains a range of productivity aids that can dramatically lower the effo rt of building, calibrating, running and maintaining a model. Prod uct ivity features can be categorised u nder rwo headings - technical features, and interface feat ures.
Technical features The best modelling sofrware undertakes a number of rhe simple but time-consuming tasks ch at are required during the model build process chat ocher sofrware products leave to the user. Data checking and cleaning provides an example. This activity is someti mes thought to require human intervention, but in fact once the rules have been established the checking is merely examining each number or attribute against a check list and flagging anomalies - a task
Journal of the Australian Water Association
chat sofrwa re can undertake far better, and at a much lower cost, than people. Equally, if required, rhe sofrware can apply inference rules where errors are id entified, based on interpolation berween valid data points, and autocorrect the data. Both these processes must cake place u nd er fu ll user control, but the drudgery and elapsed time of data checking can be greatly reduced. The same principle applies to con nectivity data. Because modelling data is often imported from GIS, and GIS is nor particularly concerned with co nnectivity, connectivity errors are common in the first pass at the model. Checking th is automatically is possible in a network modelling system that has the concept of conn ectivity bui lt- in, provi ding another major productivity aid in a viral validation area. Assigning roughness coefficients can also be au tomated. Although some roughness factors are selected to d irectly reflect a specific and unusual p ipe condition, most factors relate solely to properties of the pipe, such as age and material. T he software can allocate the maj o rity of roughness factors automatically from irs knowledge of rhe pipe attrib utes, and the few unusual instances can be specifically entered. Calibration of a model is typically a major component of the bu ild effort, and irs automation can make a major contributio n to reducing build cost. Finally on tech nical features, the run rime and stability of the model is a determinant of effi ciency - in many cases run time is dead time for the modelli ng staff, and unstable models that fail d uring runs multiply th is dead time and create a hidden ad dition to the coral cost equation. Speed and stability are vital attributes to include in so frware selectio n criteria.
Interface features T he issue of interfaces can be addressed as three separate aspects chat are all keys to good productivity: the user interface, multiuser operation, and interfacing to ocher sofrware. Most modelling sofrware now has a windows-like GUI as the user interface. But for maximum productivity, ic is vital chat the interface is effective, in tuitive for W indows users, and critically, consistent
integrated design across the entire product. Where a produce is modular, and perhaps chose modules co me from different so urces, standardisation of che interface is nor easy co achieve. T he use of models cannot become standard across engineering departments, rather than being che sole province of specialise modellers, unless che interface is simple and self-explanatory. T he second aspect of che user interface is suppo rt for multi-user operation - another prerequisite of broadening the use of modelling across a department co leverage the build costs. Ideally, che software will allow individual users che scope co own and use their own models and data secs, co view models developed by ochers under security control, bur wi ll impose central control onco storage and access co each daraser. An appropriate mix of accessibili ty and control is essential to any modelling software planned for long-term use wirhin a department and beyo nd. The im port and expo rt of files of various types is essential both to efficient model bu ild, and to the effecti ve reporting of model results. In terms of model build, the most obvious lin ks required are to GIS
systems. Modern modelling software can operate in one of two ways - either having links to a single specified G IS only, or links to all the major GIS systems. In addition to importing network data from a GIS, it is also important to import terrain data and rime-varying data, including survey data and rainfall data. Boch these come in a variety of fo rmats, both open and proprieta ry. The ab ility of software to manage the import of a wide variety of formats, rather than requiring extensi ve system knowledge and rimeconsu ming manipulation by the user, affects both the model bui ld and the analys is effo rt required.
In terms of outputs, the first need is for data to be wriccen back co rhe GIS. Next, for che effective discribucion of results, interfaces co the most effective reporting is required. Close links to MS Office can now assist reporring and disseminating model resu lts. With web publishing now a realicy in many companies, export of model results directly in xml is very useful. T he essential feacure is the Aexibility to meet most common export requirements.
Management Features Management feacu res are often the lase attributes to be placed on a selection checklist, bur in face are among the mosr important if modelling is to be an ongoing core activity, reliably supporting decision maki ng within the engineering department. The pressure of deliveri ng working models and results frequen tly tempts modellers co skip the proven good practices char should underpi n their wo rk, so ic makes sense to have these activities managed by che software. T he first management requirement is data management. Every data sec should have its creation and every subsequent use and change tracked - who did what, and when. Dara properly managed by modelling software should be securely scored centrally, downloaded co the cl ient PC of che user as required, all changes there logged, and then scored again centrally in ics updated fo rm, with audit loggings, at the end of the sess ion. If there are multiple versions of data secs, chen strict version con crol muse also be applied and logged for scrutiny when required.
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D ara fla gging is another essential feature o f good data management. Many users wan t to annotate their data with so called " meradara" char fl ags, fo r each d ata item, the source, rh e d are, and perhaps the rel iability of the data. T h e abili ty to store this meradara, as data and rexr, is an essential to the intell igent use of data.
• T he annual so frware maintenance ch arge, usually a percentage of pu rchase p rice.
Model managemen t requ ires th e same d isciplines to be applied to models as to d ata. Version control is frequently igno red by mod ellers as they make changes, so good mod ell ing software w ill log and store all versions for audit as required . Equally, just as with data, wh o did what and when should be reco rded, and this is best d one by a good audit trail fu n ctio n within the software.
• T he annual cost of sofrware su pp ort, which may be bund led in to the maintenan ce charge or may incur an extra charge. Vendor companies may also be fl exible or oth erwise in charging for assistance when wo rking on a specific model, fo r example to hel p with any run problems of a particular model.
T he iterative process of modelling places undue emphasis on th e cu rrent versions of data and the mod el, and rhe users have every reaso n to ignore the process char wen t before. Go od p ractice demands th at fu ll audit and version control are maintained, as every experienced user has learned rhe hard way, and sofrware does chis best.
Cost of Modelling A final selection criterion in selecting sofrware is rhe crucial issue of cost. If rwo or more software modelling solutions meet all the technical, p roductivity and management features char rhe buyer deems necessary, the questio n arises - what are rhe comparative costs? A commo n mistake at this stage is to fail to list the full cost of modelling. The most visible cost is rhe purchase price of the modelling sofrware, and it is easy to assume that, although there are clearly costs b eyond char initial outlay, they are likely either to fo llow the pattern of the comparative software costs - that less expensive sofrware h as lower costs - o r to assume that all other costs are identical across all products, and rhe only differen ce is in purchase price. Both these assumptions are wrong. The fact is that if the more expensive sofrware has more productivity and management features than cheaper software, it will be less expensive to u se. Ir is hard to generalise about rhe annual costs of running a mod el, b uc rhey may well amount to three to fi ve rimes the purchase cost of the software. T here are of course benefits of using the model, benefits which by d efiniti on ourweigh all the total costs if the procurement is justified. Bur when the selectio n d ecision is cost based, after all ben efits of using the models have been assessed , it is viral that full costs are taken in to account. These full costs are the sum of:
Software costs • The pu rchase price of the sofrware, fo r all modules required at the rime of purchase and into rhe future • The purchase p rice of new releases and upgrades - some manufacturers charge, and some d o no r • The purchase price of any third party sofrware rhar is essen tial to rhe running of the modelling software
Journal of the Australian Water Association
Training costs • The costs of staff train ing, noting th e o ptimum amount of trai ning of a number of staff for effective use of rhe mod el.
Staff costs • T he full p ayroll co sts of rhe staff that build and run the mod els. These costs, possibly a propo rtion o f the full costs of a number of staff rather than a single d edicated staff member, are likely to be large in comparison to w ith software costs, and therefore to be the do minant cost. All these costs differ accord ing to rh e so frware, bu r fo r rwo reasons there is a general rule that mo re p roductivity and management fearures in software lead to lower staff costs .. First, if tasks are automated they need less staff resource to undertake. Second, if tasks are automated and interfaces are simple to use, these simpler elements of mod el building and operating could be undertaken by less skilled and lower paid staff. If staff costs are indeed the domin ant element of true costs, then rhe sofrware that p rovid es the most effective productivity support will prove rhe best buy, o ther things being equal.
Selecting Software In the light of all the above, rhe read er can draw up a good checklist for so frware selection. H owever, there is a chicken-and-egg problem: in filling in such a framework accurately w ithout derailed knowledge of the sofrware, the user does nor really know how a product performs until after purchase. T he solution adopted by many companies is to forma lly ben chmark products with live prototypes in a pre-purchase phase, within an evaluation framework that is truly representative of rhe planned future use of rhe mod el. If successful , the work is n or wasted. If the mod el does nor work o ur well, an expensive and lo ng-term mistake is avoided. T he selection and impl ementation of modelling sofrware for ongoing decision support throughout an engineering departmen t and beyond is a d ecisio n char will have an impact for at least fi ve years into the fu ture. It is worth purring in the effort to get it right.
The Author Paul Banfield, based in Sydney, is Sales and Marketing D irector of W all ingford Sofrware, with experience into th e d evelopment of W ater Distri butio n Modelling technologies and techniques as currently applied th roughou t Europe, Asia, Australasia and N orth America. Emai l paul.banfield @wallingford sofrware.com