CSIRO urban water program
Volume 26 No 5 September/ October 1999 Journal Aust ralian Water & Wastewater Association
Editorial Board F R Bishop, C hairman
B N Anderson, D Deere, P Draayers, W J Dulfer, G Finlayson, G A Holder, P Johnstone, P Nadebaum, J D Parker, M Pascoe, A J Pricstlcy,J Rissman, F Roddick, EA Swinton
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From the Federal President ... ..... ... ... ..... ....... ................................ ................. 2 From the Executive Director ...... ...... ....... ....................... ..... ... ... ... .. ...... .. .. .... .. 4 MY
Names, Innovation and the New MIiiennium .................. .. .. .... ..................... .3 J G Parker WATER ·, CSIRO's Urban Water Program: A National Approach to Water System Efficiency and Sustainablllty . .. .. .. .. .. .. .. .. .. . ... .. .. ... . .. .. . .. .. .. .. .. ... ... . .. .. . . .. .. . .. . . .. .. 9 A Speers ·, Condition Assessment of Large Diameter Water Mains .......... .. .... .. .... 15 J Dymke, P Fergu son WASTEWATER ·, Storing Recycled Water in An Aquifer: Benefits and Risks .................. 21 P Dillon, S Toze, P Pavelic, S Ragu sa, M Wright, P Peter, R Martin, N Gerges, S Rinck-Pfeiffer ENVIRONMENT
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Federal President Greg Cawston
Trees or 'Bugs'? Which Are Better at Removing the Nitrogen in Effluent Used for Irrigating Plantations? .... .. .... ............................................. ..... .. ... 31 M Adams, J O liver ·, Effects of Radlata Pine Plantations on the Hydrology of A Small Catchment at Croppers Creek, Victoria ................. ... ........ ... ...................... 33 L B ren, P H opmans, D Fli nn BUSINESS
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the Water Services A ssociation ofA ustra.lia, is approaching the end of th e feasibility stage of its Urban Water Program which aims to reduce costs, make water systems more sustainable and drive assets harder. Ph oto courtesy of Tracy Nich olls, CSIRO Building, Construction and Engineering
Some Parting Words I will soon be handing over the role of President to Allen Gale who, as the sole nominee for that position, will be taking over from me in November this year. As that time approaches, I have been wo ndering w hat I can claim to have left as a mark of my term of office as President of AWW A. It occu rs to me that, if our Councillors sign off on our new Constitution and our change of name, I will actually be the last President of AWW A, while Allen will be the first of the Australian Water Association-the same orga nisation, but with a different, broader emphasis. Although the decision, in principle, to change our name was taken in my term, I feel it was simply the result of a long process, begun in 1994, of thinking about the question, teasing out options and, I am sure, arriving at the logical conclusion. So, although I am glad that that happened during my term and that I will er;joy a particular spot in history, I don't lay particular claim to the outcome. I wondered about the Inte rest Groups, some of which are well established, and some of which are only now taking shape-they were really David Hope's brainchild and it was a pleasure for me to install David as Director-atlarge so he could ensure their ultimate success. I am convinced that our ability to be relevant to many different water people, and to build our profile nationally, will hinge on the functioning of the Interest Groups. Ultimately, I concluded that there are two key outcomes that I can claim to have shepherded to success: the creation of portfolios for the Executive Committee 'Directors' and the initiation of special projects. Although our current Executive Committee structure (of six directly elected people) has been in place since our last rule cha nge in 1993, the Executive Committee tended to be a bit amorphous, with some overworked members and some less so, as well as a lack of role clarity. During my term, we have been able to give each Director a clear portfolio and to align t hose portfolios with strategic plan goals, with budget items and with staff in Federal Office. This has allowed each member of the Executive team to have clear goals, an idea of resources available and financial results required, and access to staffers
who provide horsepower for getting things done. All that is pretty simple in management theory terms, but it has been a challenge in a large organisation with mixed input from volunteers and employees. I have been very pleased with the results and with the performance of the Directors. I am sure several of them will return to the Executive Committee in the next term, so Allen Gale will have their support too. I h ave been especially pleased, though, by the success of two of the special projects to which we allocated some of the surplus from the excellent 17th Federal Convention in Melbourne
proj ec t taking off, since there is a desperate need for bright students to see a career in science, and especially water science, as attractive. Apart from those who do take up water oriented careers, the exposure to water issues can only h elp us create a more informed community to deal with the many issues that are going to be faced in years to co111e. A larger sum, just under $40,000, was alJocated to producing our first multi-media CD-Rom, designed to deliver useful information in an entertaining way to pupils and their teachers. A team in Adelaide led by Angela Colliver laboured long and hard over this one, supervised by a n ational AWW A committee. Although the CD was officially launched at the 18th Federal Conve ntion in Adelaide, wrapping up the technology proved a challenge and it was late June before the final product was out on the street. It was worth the wait, though, because the disk contains a wonderful selection of resources for teac hers and students from kindy to year 12 and beyond. There are games, quizzes and songs, as well as career profiles, case studies and teachers' units. We hope to sell our first batch widely, then look towards expanding the content and considering an update in a year or so. Being given the opportunity to be President of AWW A was a great thrill for me and I've had a fabulous time over the last two years. I've been lucky to have had the support of both a committed Executive team and a dedicated Federal Office staff, w hose professionalism has continued to grow through the leadership of Chris Davis, our Executive Director. In carrying out my role, I've had the opportunity to meet many great people from around Australia, as well as from overseas. It always heartened me to see so many people giving so much of their time in volunteer efforts. The real strength of AWW A is that it brings people together to learn and experien ce new things, and m ore importantly, to 'enjoy' the industry that we are part of. So in closing, having worked closely with Allen Gale over a number of years, I am confident that he will do a tremendous j ob as President of your association. Please give him your support. Greg Cawston
'The real streng1h of AWWA is that it brings people together ... to enjoy the industry that we are part of.'
WATER SEPTEMBER/OCTOBER 1999
in 1997. Those are the Stockholm Junior Water Prize and the educational CD-Rom. We set aside $15,000 to kick-start the Stockholm Junior Water Prize in Australia. This involves running a local competition for water projects by high school pupils, then sending the winner to Stockholm in August to compete for the Stockholm Junior Water Prize. We commenced the project last year and Rio Tinto generously agreed to support it, allowing our seed funds to go back into the pot. As you may have read elsewhere, Jonathon Duniam from Tasmania won the local competition in Adelaide last April. At the time of writing, we had booked for Jonathon and me to go to Stockholm in August and, by the time you read this, the result will be known. I am particularly happy to see this
A National Approach to Water System Efficiency and Sustainability A Speers Abstract The Australian water industry is undergoing significant reform, the outcomes of which will require it to become more efficient, achieve a better financial return for its owners and face aggressive competition. Additionally, customers are expecting better value for money and improved environmen tal performance. In conjunction with the Water Services Association of Australia, the Agricultural and Resource Management Council of Australia and New Zealand, and the Australian Water and Wastewater Association, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) is leading a multidisciplinary project-the Urban Water Program (UWP)-which is directed towards achieving improved environmental and economic performance for water systems withi n the context of socio- economic and climatic change. This paper describes the feasibility stage of the program and outlines the four tasks involved. It also sets out benchmarks for measuring the success of the program.
Urban Water Program
Key Words Urban water, Urban Water Program, (UWP), CSIRO, urban water research.
Introduction The urban water industry turns over about $5 billion annually. H owever, this statistic understates the significance of the industry since the value of water to society goes beyond its contribution to economic wellbeing. The benefits of water in terms of quality of life and protecting commu nity health are immeasurable. It is evident that steps can be taken to improve the efficiency of urban water
systems and to minimise health risks and environmental impacts arising from their provision. To demonstrate the potential of alternative approaches the CSIRO has initiated a m ul tidisciplinary research program called the Urban Water Program (UWP) in conjunction with the Water Services Association of Australia (WSAA), the Agricultural and Resource Management Cou n cil of Australia and New Zealand (ARMCANZ ) and the Australian Water and Wastewater Association (AWWA). The Urban Water Program began in May 1998 and, assuming it is re-funded at the end of the feasibility stage in November 1999, will continue for a further 18 months, with the likelihood of spin-off research continuing after that. This paper describes the UWP's intent, 'drivers,' components and benchmarks for assessment of its success.
Vision and Alms The vision determined by the UWP Steering Committee is: WATER SEPTEMBER/OCTOBER 1999
WATER ' in th e face of economic, social and climatic chan ge, enable Australia 's urban water systems to improve services to the community and improve economic pe rformance w hi le achi eving ecological sustainability.'
Th e UWP will develop a series of indica to rs of susta inability aga inst w hich movement toward development of m o re su stainable systems w ill be measured . It is funda m ental to the UWP that the solutions developed be eventually tai lored to the circum stances in wh ich they wilJ be implemented. It is A critical element of thi s vision is its most unlikely that blan ket solution s wilJ impli catio n that the UWP must be be avai lable, e.g. that land d isposal of dynamic. The tim efram e over whjch effiuen ts should be favoured over water the concepts in the UWP will be imple- disposal in all conditions or that mented is 10-50 years. It is therefo re recycling is necessarily a desirable goal essential that the context fo r impleme n- w hen water is abundant. The re is debate abou t the exten t to tation is investigated. It is not inte nded that a 'foresighti ng' exercise be carried w hich the availability of water is a out in the manner of the C urbing O ur ba rrier to populati on and econo mic Thirst report published by ASTEC growth in Australia. T he recent report (Au stralian Science and Tech nology Water and th e Australian E conomy (AATSE & !EA , 1999) sugges ts that water w ill 'A critical element of this vision not, in fac t , inhibit as long as it is is its implication that the UWP growth the reallocated to ' highes t va lue' uses. must be dynamic.' Neverth eless, as t he report also states, it is Co un cil). Rathe r, ' boundary condi - incumbent on us to i mprove the tion s' fo r fu ture wate r syste ms will efficiency w ith wh ich water is used. be d eve lo ped th rough surveys of More efficient water use in urban areas customers, ope rators and regulators. would , fo r example, make water potenThese bou ndary co nditi ons will incl ude tially available fo r environmental flo ws factors such as co mmunity attitudes or other purposes. T his report says little and expectations, rn.ini mum required about the li mits to be placed on the service levels, cost, techn ical feasibility, di sch arge o f wastewa ters to th e operational require men ts and cli mate environ m en t , a facto r w hich also chan ge. requ ires resea rch. To ensure rigour in thi s process, the A particular driver o f the costs of concepts developed wi ll be modelJed existing system s is the co st of ' transu sing a 'test-case' site in P erth's north- portation' (i.e. the costs of transporting east developmen t corridor. An indu stry water arou nd the system, including the reference group (IR.G) has also been infrastructure required to do so). T hese esta blished to provid e input and costs comprise 60-70% of operational feedback on e merging alternatives. The costs, o r some billion dollars per IRG includes representatives of water an num. Further, it is common ly compani es, appliance and pipeline assum ed that there are eco nomjes of manufacturers, developers, health and scale co ntinu ously ava ilable in the enviro n me n tal regul ators and ot her ce ntral isa tion of (particul arly) wastewate r transport and treatm e nt system s interests. that lead to th e pattern of infrastructure The UWP has three clea r goa ls: • to reduce significantly the ecological that is provided curre n tl y. If suc h impact of Australia's urban water use economies of scale are shown through a more comprehe nsive analysis of transand wastewater disposal • to redu ce the importance of water port costs to be smaller than anticipated availabili ty and wastewater di sposal as or to become disecono mies at a certa in point, the design of water systems in li m its to the growth of Australia's cities future may be fundame ntally differe nt. • to reduce the costs of water , wasteThese aims and th e examples given water and stormwater service delivery describe key outcomes from the UWP , by 25% per unit of wate r suppli ed. It is not the UWP's intention to but are not necessarily intended to b e defi ne 'sustainabili ty' or to describe an exhaustive. optimum system. R athe r, given existing system s cause evident environ m ental Structure of the Program impacts, the UWP aims to work toward It is useful to think of the UWP as systems that: comprising four tasks, at least during its • reduce pressu re on water resources feasibi ljty stage. These tasks are articu• improve management of nu trient lated me rely for ease of unde rstanding and contaminant flows in water systems and are not sequential or discrete bu t so tha t adverse impacts are prevented w ill overlap as data and research are • reduce materials and ene rgy use. integrated. 10
WATER SEPTEMBER/OCTOBER 1999
The fi rst task is the developme nt of an understanding of critical charac teristi cs of urban water system s to ide nti fy op po rtuni ties for improvem ent and gaps in knowledge. This understanding is used to establish a benchma rk aga inst w hi ch th e alternatives emerging from the program can be measured. The critical characte ri stics include th e pa ttern of water flows in the system (water balance), nu trient and contaminant fl ows (con taminant balance), th e drivers of the design of water, wastewate r and stormwa te r systems, an d transport costs. As water is the medium by w hich contaminants are transported in urban wa ter syste m s, a com mon mapping system wi ll be employed for wate r and co ntaminant fl ows. This map will iden tify in puts of water and contam inants, including overland stormwa ter flows, and wi ll trace thei r pathways and transfo rmations in the sys t em. Transformation s occur due to both onsite degradation of co ntami nants and the growth of biofilm and as a result of trea tment processes. Variations in flow will be calculated for daily and seasonal peaks. M ass balance calcu lations will be perform ed on contaminan t flows. Co n tam inants mapped will include heavy m etals (Cu , Z n , Pb), nutri ents (total, N , NH3-N , total-P), ino rgan ics (TSS , TDS), orga nics (COD TOC, BOD, H eptachlor as a representative pesticide, PAHs, oil and grease) and path ogens (coli forms). A series of t ables wi ll describe inputs at the fl ux points (e.g., nutrient inpu ts at particular p oi n ts in a household). Being a feasibility stage program , much of th e data fo r thi s m odell ing com e from existing so urces, although they will be collated in new ways to prod uce t he m odelling outcomes required. An original in pu t to the wate r balance is a study of patte rns of domestic water use. T he Wate r Co rpo rati on (W estern Au stralia) and CSIRO are collaborating in this study, w hic h is a detailed analysis of indoo r and external pa ttern s of water use. The Water Corporation undertook a similar study in 1983/84 and th e results of this study are well respected in the water industry (MWA, 1985). The parameters of the more rece nt study are similar, bu t new technology, including 'smart meters' capable of recogni sing the signatures of water-using appliances, will be use d. In total, 720 househo lds have bee n recruited for the study, of w hi c h 600 wi ll record water use in a diary. The remainder will also complete diaries, but these records will be compl em e n ted by data from the smart meters. To date, the first su mmer's metering of about
WATER four months has been completed. Summer is the time of peak use, w hen there is very little rainfall at the study site. It is hoped that the study can conti nue into a second summer to provide an extended baseline of data. Costs of urban water systems traditionally include capital and operating co sts, including maintenan ce. T hese costs are included in net present value calculations to determine the feasibility of capital expenditure. What is generally not included , however, is the total lifecycle costs of infrastructure, includ ing-as well as capital and operating expenditure-disposal and embodied energy costs. Also not included are externalities (generally those costs and benefits enj oyed by third parties w ho do not pay for the benefits received or who are not compensated for losses) . Externalities too represent costs in the system and must be considered if a view of total system costs is to b e gained. In its feasibility stage, it is not anticipated that fu ]J lifecycle costs and externalities will be quantified. Rather, a methodology for lifecycle costs will be developed and applied using existing data, and a 'ranking' of externalities will be d eveloped , based o n t heir likely magnitude, and characterised for the range of urban water systems com monly in use in Australia. T his will form the basis fo r sensitivity analyses comparing t he existing systems wi t h the n ew concepts that emerge from the program, among other things. The co sts of existing system s represent 60- 70% of the cost of service provision (AATSE & IEA, 1999). Particular attention will therefore be paid to u n dersta ndi ng these costs. There are two perspectives to this work. The first, as referred to above, is to begin to quantify system costs, including lifecycle costs and externalities. This quantifica tion wi lJ b e analysed to determine whether the economies of scale said to exist in infrastructure provision are in fac t available. If not, or more likely if there are diseconomies of scale reached at a parti cular level of centralisation, fundamental questions would be raised about current sys tem design p rac tices, as the most effi cien t approaches may be fou nd to be toward greater decentralisation. T he second perspective is to ide n tify ways of mitigating transport costs, say through a levelling of peak flows, allowing smaller, cheaper pipes to be installed. A fall i n transport costs may make approaches such as localised treatm ent of wastewaters viable, whereas th ey are currently considered unecono m ic. Transport cost analysis will therefore be a fea ture of the UWP in its feasibility stage. By identifying the characteristics of
Sustainable urban water systems could 'free up' water for other uses
flows and co sts in existing systems, a ben chmark will be established against which alternatives can be assessed. Complementing this wilJ be identified i ndicato rs of su stainability , against which alternative techno logies and integrated alternative scenarios wilJ be measured . Identificatio n of these indica tors completes the activities to be undertaken as Task 1 of the UWP. Task2
risks to system operation in the future. Th ese facto rs are also social and economic, but include climate change, which may pose a risk to supply security (both quality and quantity) or which may affect the adequacy of downstream infrast ru ct ure, su ch as stormwater systems. CSIRO is using innovative approaches to the downscaling of global climate model sim ulations to determine impacts on local system performance under a range of scenarios (Charles, 1999). The combined ou tcome of T asks 1 and 2 w ilJ be an understanding of existing system operation and cost and t he i de n tifi cation o f opportuniti es for improvement within a realistic socioeconomic and climate change context. These factors will be 'bou ndary condi-
This co mponent of the work is directed to identifying feasible alternative approaches and th e socio- eco nomic and physical context in which they might be implemented over the 10- 50 year planning horizon of the UWP. We have been careful in our choice of the term 'alternative approac hes' rather than 'alternative technologies.' While 'It is vital ... that benchmarks of n ew and e me rging tec hnologies will be performance be established for investigated thoroughly in t his program , new the UWP' technology is frequently applied or seen to have tio ns' within which alternative 'scenarthe greatest application at the 'end-ofios' of urban water service prov1S1on the-pipe.' Such a concentration would will be developed in Task 3 of the be cou nterproductive. Our approach program. will therefore be to con side r new management m ethods alongside new Task3 treatment and transport technologies. Task 3 is the development of realistic We con sider it essential that the alternative scenarios using data from the alternatives we do propose are realistic first two tasks and input from two critiwithin th e context in which they will be cal sou rces. The first of these sources is implemented. Consequently, consider- the IRG (industry reference group). able effo rt w ill be put into determining T he IRG will be directly involved in customers' m inim um requirements for th e development of the scenarios, the service delivery and barriers to accep- provision of data and the challenging of tance of new approaches, be they social, assumptions underpinning the scenarios regulatory, technical or economic. This that emerge. work will be based largely on attitudinal The second inpu t source is the use of surveys of cu stom ers, operators and a test-case site in Perth 's north- east others. development corridor. T his site w ill be Similarly, there is a need to identify u sed as a basis for co nceptually those 'change factors' that m ay pose modelling the alternative approaches WATER SEPTEMBER/OCTOBER 1999
WATER proposed. U se of a real-life example is intended to add rigour to our analysis through the use of actual, not theoretical, data. In this feasibility stage it will not be possible to state definitively w h ere opportu ni ties exist or whether opportunities that exist, say, within th e test site will be available at other locations. Rather, we wish to be able to say, with a high degree of confidence, whether or not opportunities of some significance are likely to be available, depending on local circumstances and whether or not they will be worth pursuing (i.e. whether further research is likely to bear fruit). of specific Identification research needs, assuming such opportunities are proven to be available, is also an outcome. It is not therefore problematic that the test case site is not fully represe ntative of conditions in o the r parts of the nation. Nevertheless, the site has been selected to contain a range of conditions that may obtain in other areas. For example, it includes a greenfield development area Driving assets harder Is critical In the CSIRO's (Ellenbrook Estate) and areas Water Program that have been established for many decades (Midland). It includes areas of sandy soils and areas of core models. The first-Urban Volume and clayey soils (which are uncharacteristic for Perth) and it contains a range of Q uali ty (UVQ)-controls data arising industry types (including the light from water and contaminant balance industrial area and Bullsbrook Airforce work and will run at the 'front-end' of efficiency modelling to determine the Base) and landuses. To date, four preliminary scenarios impact of alternatives on water and have been discussed with the IRG. contaminant flows. This model will be based on the Aquacycle (Mitch ell, These are approaches that: 1999) model developed by the • maximise asset use Cooperative Research Centre for • minimise demand • can be applied at scales ranging from Catchment Hydrology. The model will household, through clusters of house- produce daily water flows and contaminant loads to and from the various holds up to catchments and demands in an urban area. sources • promote more effective nutrient This approach will also reveal points in management. These are preliminary scenarios only. the water, wastewater and stormwater In the final event, combinations of systems that will have particular priority elements of each of these and poten- in terms of water management and contaminant impact reduction. An tially others will be represented in the interative process will therefore occu r final scenarios that are proposed for between the design of alternative furt her analysis in computer- based scenarios and their testing. modelling systems. The second model-TAWS (Tool Task4
Task 4 comprises the development of models to compare the relative efficiency of alternatives against the base case. It also comprises modelling the impact of these alternatives on contaminant and water flows and potentially other characteristics. There are three 12
WATER SEPTEMBER/OCTOBER 1999
for Analysis of Water Systems)-is being developed to compare the relative efficiency of alternatives. It is based on the Integrated Water Resources Decision Support System (Gilbert, 1997), a key outcome of early investigations by CSIRO into urban water planning and management.
THE TAWS model represents the urban water system using two networks: logical and physical. The former captures the supply, demand and disposal dependencies between different water sources and consu mers, whereas the latter represents the actual t ransportation system. Changing the supply, demand and disposal dependencies of the logical network can generate alternative water supply and disposal resource scenarios. Scenarios ca n be generated manually for 'whatif analyses or automatically as part of optimisation. The underlying models can then predict the p racticality and cost-effectiveness of the The va rious scenarios. optimising mode can identify the most cost-effective of all available approaches. The original IWRDSS included only the water supply system. Enhancements to develop TAWS will include its extens10n to wastewater and stormwater systems. The third model is the Scenario Manager. This 1s a front-end in terface between the underlying models and the Urban user, allowing the various scenarios to be described to the system and results to be represented in an understandable fashion . The Scenario Manager can 'plug and play' various underlying models for analysing flows and comparing costs, depending on the preference of the user. It therefore has a great deal of inbuilt flexibility. These models will allow effective comparison of complex and multivariate scenarios and combine data on flows, transport, treatment and infrastructure costs and other factors.
Benchmarking Success of the UWP Extensive accountabilities are built into the structure of the UWP. A highlevel Steering Committee oversees the program, and regular reports are made to the Water Services Association Research Committee and the IRG. It is vital, therefore, t hat benchmarks of performance be established fo r t he UWP itself. The following general performance criteria have been sp ecified: 1. Demonstrate knowledge of patterns of domestic water use specifically, and commercial and industrial water use generally, that lead to identification of opportunities to reduce demand or improve service provision
WATER 2. Quantify characteristic contaminant and nutrient flows, including pathogens, m water, wastewater and stormwater systems 3. Analyse transport costs, including externalities and lifecycle costs, leading to identification of ways to reduce these costs or improve service provision 4. Identify technologies with the potential to reduce costs facing the water industry or increase efficiency, particularly in the fields of: pipeline maintenance pipe-laying and longevity water and wastewater treatment â&#x20AC;˘ stormwater management (including treatment, velocity reduction, pathogen reduction, etc.) 5. Based on the above, identification of new configurations for water, wastewater and stormwater systems which reduce costs and/or improve the efficacy of new systems. Additionally, and more specifically, key benchmark figures will be identified against which proposed improvements can be measured. As outlined above, the UWP has three aims. These arc cost reduction (S), increased sustainability (S) and reduction in resource scarcity as a barrier to growth (G). Measures of performance, which will be derived as an average for the Australian water industry, based partly on data in the Water Services Association WSAA!acts and partly on other sources, are set out below. (The symbols in parentheses refer to the aims the criteria will be used to measure): water use per capita (S, G) cost of service (S) average pipeline costs (S) characteristic nutrient ÂŁlows (S) potable and secondary water availability per capita (G).
Conclusion The Urban Water Program is an integrated multidisciplina1y program aimed at fundamentally re-evaluating the operation of existing urban water systems to the benefit of the Australian economy generally and water companies and their customers specifically. If successful, proof will be provided of the potential for significant gains to be made and research directions will be identified for the program's postfeasibility stage. The UWP is designed to respond to factors driving reform in the Australian water industry and to further those reforms. The establishment of indicators of performance for the UWP itself will ensure that its outcomes are quantifiable. Progress up to the time of writing has been good and the t\vin goals of offering better sustainability and lower costs for Australian urban water systems seem attainable.
References ASTEC (1995) Curbing our Thirst: Possible Futures for Austrnlia's Urban Water System in the 21st Century. Australian Science and Technology Council. AGPS, Canberra. Australian Academy of Technological Sciences and Engineering and the Institution of Engineers, Australia (1999) Water and the Austr.1lia11 Economy. Australian Academy of Technological Sciences and Engineering, Parkville, Victoria. Bates B C,Jakeman AJ, Charles SP, Smnner N R and Fleming P M (1996) Impact of Climate Change on Australia's Surface Water Resources. In: Greenhouse: Coping with Clinrnte Change. Bouma W J, Pearman GI and Manning MR (eds.), CSIRO Publishing, Collingwood, Victoria, pp. 248-262.
Bates BC, Charles SP and Hughes] P (1998) Stochastic Downscaling of Numerical Climate Model Simulations. Environ. Model. & Software, 13(3-4), 325-331. Charles S P, Bates B C, Whetton P I-I and Hughes J P (in press) Validation of a Downscaling Modd for Changed Climate Conditions in South-\.vestern Australia. Clim. Res. Gibert J and Maheepala S, Applying the Object-oriented Paradigm to lntq,rrated Water Resource Planning and Management. In E11vironment,1l So[t\varc Systems, Vol. 2, Chapman & Hall, 1997,
Maheepala S and Gibert j, Optimisationbased Model for Integrated Water Resource Planning, Proceedings of the 24th Hydrology and Water Resources Symposium, Auckland, New Zealand,
24-27 November 1997, pp. 456-461. Maheepala S, Gibert j and van der Wcl B, Toward Cost-effective and Sustainable Water Resource Development in the Spencer Region of South Australia (in press) Proceedings of the Water 99 Joint Congress of Second International Conference on Water Resources and Environmental Research and 25th Hydrology and Water Resources Symposium, Brisbane, Australia, 6-SJuly
1999. Metropolitan Water Authority (1985) Domestic Water Use in Perth Western Australia, Perth, WA. Mitchell V G CJ 999) Aquacycle: An Urban Water Balance Model for Assessing Stormw.1ter and W.1stew.1tcr Reuse Options: User M.1nual. Cooperative Research Centre for Catchment Hydrolot,ry, Monash University, Clayton, Victo1ia.
Author Andrew Speers is Director, Urban Water Program, Commonwealth Scientific and Industrial Research Organisation, PO Box 310, North Rydc NSW 1670. He can be contacted at email: firstname.lastname@example.org
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BOOKS Towards a Financially Sustainable Irrigation System K John Langford, Christine L Forster and Duncan M Malcolm are the authors ofWorld Bank Technical Paper No 413 (ISBN 0-8213-4286-X). Available from the World Bank, email: email@example.com or in Australia from DA Information Services, Mitcham, Victoria, fax (03) 9210 7788 for $ 33.75 per copy plus postage. Limited copies are also held by Dr J Langford, Executive Director, WSAA. T his publication o f 95 pages, including an Executive Summary and seven chapters, se ts out the wate r reform process applied to the irrigation industry in the State ofVictoria in the period 1984-1994. Irrigation water reform is well interlinked with the historic fabric of Victoria. Irrigation in Victoria offered an opportunity to manage the extreme climatic variability in the continent and the reform process was necessary to position agriculture to take advantage of emerging in ternational markets. The authors highlight how episodes of drought in the 1890s, financial crises
of p rivate irrigation sc hemes and Royal Com missio ns resulted in the State Government m oving to centralised control via the State Rivers and Water Supply Commission in 1905. Vesting the use and flow of rivers and streams in the C rown was a benefit while fixed allocation of water rights in the long run was not. In the first few decades of the 20th century water was treated as a social rather than economic good, and the governmen t promoted intensive irrigation before changing to pasture-based irrigation in the 1930s which in the long ru n proved a disbenefit. T h e impact of a high level of accumulated debt, replacement of infrastru cture assets, coupled with highly subsidised water and transport u tilities, forced the government to implement eco nomic reform in the 1980s. T his was highlighted by the Public Bodies Review Comm.ittee during 1980-1983. Floating of the Australian currency in 1984 and globalisation of national eco n omies exposed Australia to competition in agricultural products and exposed the low productivity for irrigated agriculture.
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T he Victorian Gove rn ment focused on eco n omic reality by restructuring, efficient management of government business enterprises, realistic pricing and setting clear financial targets. The book sets ou t the decision making in the $400 m illion debt w hic h could not be treated as an opportunity cost due to the parlous state of irrigation farme rs and hence became a sunk cost. T he authors reveal the restructuring which began with the SR&WSC in 1984, sepa rating functions, so that the R ural W ater Commission concentrated on rural water supply functions and and resource Department of Water R esources on policy and regulation. It is worthy of note that in the period 1984 to 1995 the financial stra tegy reduced the shortfall from $66.9 millio n to $13.3 million. Non-core activities were sold off, wa ter allocations were reformed, asset management and accounting systems were restructured, and staff reform and training and environmental sustainability and mitigation methods were put into place. One key part of restructuring was the move from a centralised structure more suited to a capital-in tensive construction organisation to a highly specialised operations and maintenance business, and this resulted in four autonomous regional authorities responsible for irrigation functions in 1994. The publicati on de tails the Victorian experience, but it would be an appropriate model for irrigation systems in developing countries and probably in some devel oped countries. T here are a number of good lessons to be learnt from perusal of this publication of advantage to experienced practising engineers and new graduates alike. Frank Bishop Egis Consulting
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CONDITION ASSESSMENT OF LARGE DIAMETER WATER MAINS J Dymke, P Ferguson Abstract T his pape r provides a methodology for condition assessment oflarge diameter wa ter mains using a combination of desktop and field tec hniques including remote field technology (R.FT) M ainscan®, di rect physical measurement of metal and coating thicknesses, linear polarisation resistance (lpr) soil testing and extreme va lue statistics. T he results provide an indication of the classifica tion of risk of failure for each mai n and allow the water authori ty to plan the most appropriate action. A sum mary of the condition assessment of the external su rface of ACTEW's 20 km 35- yea r-old DNl 600 mild steel B endora G ravity M ain (BGM) is also given.
Key Words Pipeline, con dition, investigatio n, critical mains, soil testing
Introduction Large diameter water mains (DN300 and above) are a vital part of the water indu stry. The vast majority of these pipelines are grey cast iro n , steel, wrought steel or ductile cast iron. Some have been in use for more than 100 years and have been constructed using a variety of j ointing methods, including rubber rings, lead and welded joints. A variety of external protection systems has been used including cemen t mortar (Gunite), coal tar en amel w rapped , fu sion bonded polyethylene, loose polyethylene sleeving and thin paints. Lining systems for internal corrosion include cement mortar, coal tar epoxies and thin paint. Many of the mains are buried and exposed to a variety of soil conditions, but a significant number have been installed above grou nd. This paper provides a methodology for condition assessment oflarge diameter mains u sing a combination o f desktop and field techniques including: • RFT Mainscan® • direct physical m easurement of metal and coating thicknesses • linear polarisation resistance (lpr) soil testing • extreme value statistics. The results provide an indication of
the classification of risk of failu re for each main or for sections of a main and allow the water authori ty to plan the most appropriate ac tion. Finally, a su mmary of the condition assessment of the external surface of ACTEW's 20 km 35- year-old DN1600 mild steel B endora G ravity Ma in (B GM ) is presented. For the major part of its length the pipeline traverses the Cotter River catchment and is located in an area of severe topographical conditions, with pipeline gradients of up to 40% . In general, the assessment fo und the conditi on of the main to be good, but identified several items requiri ng remedial action to minimise risk of failu re on the pipeline.
Critical Nature of Large Diameter Water Mains Large diameter water mains (DN300 and above), particularly those that connect water supply storages (headworks) to water treatm ent plants and wate r treatment plants to service reservoirs, are strategically importa n t in supplying large volumes of water to con sumers. The con seque nc es of a failu re are very severe and many of these mains can be classified as being critical (VWR.A, 1993) . T he design lives of
mains are usually greater than 80-100 years and many of them are located (often buried) in difficu lt terrai n , where access for inspection and refurbishment is restricted. These mains form a signi ficant component of the water supply authority's 'balance sheet.' T h e questions asked by Asset Management are: Will the main achieve or exceed its design life? and What inspection and maintenance actions need to be taken to ensure the design life and performance objectives a z·e optimised? T hi s paper foc u ses on methods u sed to answer th ese two important qu estion s. ACTEW Corporation's large diam.eter water mains (>600 mm nomi nal dia m ete r) co n stitu te approximately 7.6% of the total water supply system piping length. H owever, in terms of th eir current replacement cost th ey represent 31..2% of the total value of the system . T able 1 shows the lengths and approximate replacement valuatio n of ACTEW's water mains assets. T he most cri tical part of ACTEW's water su pply system is the B GM system, connecting Bendora Reservoir on the Cotter R.iver to the M t Strom.lo Water Treatment Plan t. The main feeds up to 320 ML/d of raw water to the treatment
Table 1 ACTEW Corporation's water mains (1997 valuation) Diameter (m) 100-525 600 675 750 825 900 1050 1124 1280 1350 1420 1600 1 753 1828
% total length
Est. replace. cost
% tot al
2,656,586 53,482 18,464 29,831 7 ,898 41,089 10,430 3,553 18,474 5,347 7,619 12,187 2,044 7,600
92.42 1.86 0.64 1.04 0.27 1.43 0.36 0.12 0 .64 0 .19 0 .27 0.42 0.07 0.26
482.81 35.76 13.85 25.36 7.50 45.20 12.41 4.44 24.02 7.49 11.05 18.28 3.27 12.92
68.64 4.94 1.97 3 .61 1 .07 6.43 1 .76 0.63 3.41 1.06 1.57 2.60 0.4 6 1.84
CICL, DICL, other DICL, MSCL, other MSCL MSCL MSCL MSCL MSCL MSCL MSCTEL MSCTEL, MSCL MSCTEL MSCTEL MSCL MSCL
CICL = cast iron cement lined DICL • ductile iron cement lined MSCL • mild steel cement lined MSCTEL • mild steel coat tar epoxy lined Other • unplasticised polyvinyl chloride and asbestos cement
WATER SEPTEMBER/OCTOBER 1999
Soil environment Exposure time (age) Condition of coating
0' 0 0
Exposure time (age)
Condition of lining
Original thickness , . . , Thickness of metal
IMaterial properties j [ ) I
•a e aa
Q Strength of pipe
' ' '
Weakening of pipe
Figure 1 Relationship between pipel ine features and strength of pipe material
plant and supplies 95% of Canberra's bulk water supply. A condition assessment was conducted on the series of mains comprising the BGM sys tem using a variety of techniques described below. This identified high risk regions along the pipeline and recommended remedial actions to drastically reduce the risk of a mechanical failure on the pipeline system. A C TEW 's key interest in the con dition assessment of this system w as to determine the present and future condition of the buried steel shell, which is coated and lined with a coal tar epoxy system.
D Ductile iron/steel
• Cast Iron/asbestos cemont •
Plastic/glass reinforced plastic
Figure 2 Failure sequence of pipes (Ferguson and Nicholas, 1992)
Investigation Methodology The various techniques that can be used to investigate th e condition of a large diameter main are significantly influe nced by the availability of access to the main and the pipe joints, e.g. welded, rubber ring o r lead pac ked. The main factors that require investigatio n fo r condition assessmen t of a large diameter ferrous metal main are: • metal thickness • coating assessment • lining assessme nt. These factors give an indica tion of the physical condi tion of the main.
Combined with the age of the main and the enviro nment surrounding the main, they can also give an indication of the likelihood of a corrosion failure (see Figure 1). Figure 1 shows the gen eral relationship be tween the strength of the pipe, the condition of the coating and lining, the age of the pipeline and the corro sivity of both the internal and external environments of a pipeline. Figure 2 sh ows the failure sequence of a pipe that has undergone corrosion. Corrosion weakens the pipe and if an internal or external load is applied in excess of the pipe's residual strength, a
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WATER failure will occur. H owever, it is important to note that some failures can and do o ccur without corrosion weakening. No n-me tallic p ipes fail through a variety o f m echanism s (Burn et al. , 1998) and brittle grey cast iron pipes have failed w ithout any evidence of corrosion (Ferguson, 1990).
Assessment Techniques The vast majority of large diameter water mains in Australia have been constructed of steel (including locking bar and fully welded pipes), grey cast iron and du ctil e cast iron. Consequ ently, the following techniqu es pertain to investigative methods associated with metallic pipes. Constantine et al. (1996) determined a statistical model fo r predicting the future number of pipeline failures for asbestos cement and cast iron re ti culation pipes in Melbourne. The model is useful in providing an indication of the likely performance of reticulation and non -critical mains, but is of limited use for a proactive approach in assessing the individual condition of critical ma ins where failures have either not occurred or have not bee n recorded. The determination of the residual thickness of metal is fundamental in assessing the co ndition of a me tal
pipeline (see Figure 1). M etal thi ckness T echniques used to ascertain the measurements can be performed by a condition of the external coating are variety of methods depending on ease of determined by electrical co ntinuity of access, th e length to be investigated and the pipeline and the type of coating. the diame ter of th e pipe. Three The table below summarises the various techniques are used: in-situ non- techniques employed, with examples of destructive evaluation using remote several external corrosion protection field technology (RFT) Mainscan systems. (Ferguson et al., 1996), linear polarisaThe joint areas of pipelines may tio n resistance (!pr) soil testing require special consideration if they are (Ferguson and Nicholas, 1992 and H ay, different to the barrel coating or have 1984) and direct physical measure- bee n applied in the fi eld. In som e men ts. Direc t measurements are insta nces, particularly with thi n tape divided into ultrasonic measurements 'The determination of the residual thickpit depth and ness of metal is fundamental in assessing measurements. Table 2 sumthe condition of a metal pipeline.' marises the applicability of the techniques as a function of wrapped systems, a co nservative pipe diameter, pipeline material and approach is adopted and the pipe joint is ease of access to the ma in. T able 3 considered to behave as bare unprocompares the informatio n or data tected pipe. output from the four tec hniques. Table 4 shows tha t two electrical The direct techniques can be used on techniques can be used to determine the exhumed or removed sections of the conti n uity or condition of a barrier pipeline by locating potentially high coa ting applied to a welded steel risk areas, determined by co nsideration pipeline. Direct cu rrent voltage gradiof the p ipeline route environments, ent (DCVG) survey measures the fl ow pipe-to-soil potential or direct current of electric curren t in th e soil associated voltage gradient (DCVG) survey if the with a coating defect after application pipeline is electrically co ntinuous, or (usually at an above ground appurteresistivity survey (Peabody, 1967). nance) of a direct current to the pipeline
Table 2 Compa rison of techniques for determining metal t hickness Technique
RFT MainscanÂŽ LPR Ultrasonic Pit depth
Above Below Above Above
DN150 to DN375
DN375 to DN600
Yes Yes Yes Yes
Future Yes Yes Yes
No Yes Yes Yes
Yes Yes Yes Yes
Yes Yes No Yes
or below ground ground ground or with access ground or removed samples
Table 3 Comparison of techniques for determining metal thickness Technique
Failure probability of individual pipeline elements
Able to obtain extensive and intensive information
Corrosion rate of bare metal at selected locations
Used in combination with extreme value statistics (EVS) to obtain time-to-first failure along pipeline
Remaining th ickness of steel pipe at selected locations
Used in combination with EVS to obtain time-to-first failure along pipeline or section of pipeline. Not su itable for corroded cast iron mains
Depth of pitting corrosion at selected locations
Used in combination with EVS to obtain time-to-first failure along pipeline. Requires removal of corrosion product
Table 4 Comparison of techniques for determining coating condition Type of coating
Cement mortar (Gunite)
Observation (plus chemical)
Joint condition needs to be assessed. Joints may be considered bare
Usually poor quality and deteriorating. Considered as bare
Coa l ta r enamel or wrapped coating such as Polyken YGIII
Observation and thickness. DCVG or Pearson survey if electrically continuous
Joint condition needs to be assessed. Joints may be considered bare
Loose polyethylene sleeving
Applies to recent cast iron and ductile iron pipelines. Allows access to metal if removed during inspection
Fusion bonded polyethylene
Observation and thickness. DCVG or Pearson survey if electrically contin uous
Sintajoint has extremely low risk of failure
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and the Pearson survey (Morgan, 1987) involves the detection of an imposed high frequency signal emanating from a coating defect. The assessment of internal coating (lining) condition requires access to the pipe bore. In the case of cement mortar lining, the integrity of lining is determined in-situ by qualitative chemical analysis, or determined 'destructively' by sampling a section of lining and performing a quantitative chemical test in the laboratory. The longevity of the lining is estimated by consideration of the density of the lining, the depth of degradation and the age of the main and/or lining. Barrier coatings are observed visually for obvious defects and discontinuities and their longevity is estimated from their age and past performance. The thickness of the barrier lining can be measured non- destructively. The condition (thickness) of the metal needs to be determined beneath any large coating defect.
Extreme Value Statistics Extreme value statistics (EVS) (Aziz, 1956) are used to extrapolate results obtained from a relatively small sample (e.g. pit depth measurements from several pipe exhumations, several LPR readings) to a much larger sample (ideally the entire pipeline). The diagram above shows corrosion pitting results obtained from 20 pipe sections (each approximately 0.5 x circumference x 0.5 min length and depicted as red squares) extrapolated to the entire pipe length of 70 m (representing a sample size of 7% of the entire pipeline). The method predicted a maximum pit depth of 3.1 mm along the full length of the pipeline, whilst the maximum measured value was only 2.8mm.
Investigation Outcomes The primary objective of an investigation is to obtain an assessment of the risk of failure of the main in the short term-say, within the next five years. This enables the authority to prioritise expenditure on repair, refurbishment or replacement of the main investigated to decrease the risk of failure of the main (see Figure 4). The benefits are a significantly lower risk and better use of money and resources.
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Condition Assessment of Bendora Gravity Main System A condition assessment was conducted on ACTEW'S BGM System (see Figure 5) . Table 5 compares the various techniques used on the BGM 1 pipeline and shows the outcomes of the investigation. The assessment proved
WATER Table 5 Resu lts of condition assessment of BGM1 pipeline Feature of main
A combination of pipe-to-soi l potential, DCVG su rveys, electromagnetic measurements and direct observations from exhumations. Used EVS to extrapolate beyond a small number of sample measurements
Some difficulty with assessment of concrete encased sections. However, general condition of pipeli ne coating is very good. Identified external coating of appurtenances such as scour valves as potential weaknesses
External coating-above ground
Thickness measurements and observations
Integrity of pipeline not at risk except at some bu lkheads where soil has come into contact with inadequately protected steel pipe
Thickness measurements and observations
Lining is showing signs of deterioration at some locations. However, water appears to be relatively non-corrosive
Thickness of steel shell
Ultrasonic measurements obtained at exhumed sections of main. Used EVS
No detectable pitting corrosion detected on the BHM 1 pipeline
Prudential building SE rainwater pipe
Pipeline condition assessment
-2 - ' - - - - - - - - ~ - - - - - - - - - - - - - - '
Pit depth (mm)
I -- 20th Floor - NW duct -
Deferral of capital
Figure 4 Water authority objectives for condition assessment of a pipeline
successful in identifying high ri sk aspects of the main.
The overall ou tcomes of the co ndition assessment program have been p ositive. The external corrosion protection coatings on the main were fo und to be in good condition and are still providing good corrosion protection. H owever, due to poor design and construction de tailing, remedial work is required at most of the buried scour valves to provide a less corrosive environment and improve access. The internal epoxy coating has undergone some minor deterioration and periodic inspection and refu rbishment will be required to prevent minor tuberculation of the B GM l main. The following conclu sions arose from the assessment: • all ferrous metal pipelines are able to undergo a proactive condition assessme nt • p erformance of m etal pipelines is influenced by several factors including coating type and soil environment • th e applica tion of investigative techniques depends on several characteristics of the pipeline including electrical continuity of the pipeline and the type of coating • condition assessment of a main
Figure 3 Example of use of extreme value statistics
Lowering of risk
allows better use of a water auth ority's resources and capital • co nditi o n assessment of a main provides mo re information to a water authority to allow a reduction in the risk of failure of a main.
Rehabili tation Schem es. Pipelin e Proceedings of 2nd International RILEM/CSIR.O/ACRA Conference. Constantine G et al. (1996) Predicting Underground Corrosion Failure. Water, March/ April 1996. Ferguson P H (1990) Failure of Grey Cast Iron Pipe in Wyong Shire. Internal Tubemakers R eport. Ferguson P H and N icholas D M F (1 992) External Corrosio n of Buried Iron and Steel Water Main s. Corrosion Australasia, Vol. 17. No. 4. Ferguson P H et al. (1996) Condition Assessment of Water Mains Using R emote Field Technology. Water, March/April 1996. Hay L (1984) T he Influence of Soil Pro perties on the Performance of Underground Pipelines. Department of Soil Science M.Sc. Thesis, University of Sydney, 1984. Morgan J (1987) Cathodic Protection NACE Publication, 1987. Peabody A W (1967) Corrosion and the Maintenance Engineer. National Association of Corrosion Engineers NACE Publication, 1967.
Aziz PM (1956) Application of the Statistical Theory ofExcreme Value Statistics to the Analysis of Maximum Pit Depth Data for Aluminium, Corrosion, 12. VWRA 1993 R eport No. 57 Identification of Critical Water Supply Assets. Burn L S et al. (1998) Optimisation of
John Dymke is Manager of the Water and Sewerage Assets Branch of ACTEW Corporation and Phlllp Ferguson is Manage r, Pipeline Condition Assessment, Tubemakers Water, PO Box 141, Fairfield NSW 2165.
Stromlo treatment plant
4 3.5km ON600 1920!1
•·I Stromlo junction 3b 3.5 km ON900 1940~
Cotter pump station
ON1350 to 1600 MSEL 1962
Figure 5 Schemat ic of ACTEW's Bendora gravity main system
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STORING RECYCLED WATER IN AN AQUIFER Benefits and Risks P Dillon, S Toze, P Pavelic, S Ragusa, M Wright, P Peter, R Martin, N Gerges, S Rinck-Pleiffer Abstract Reuse of effiuent on land is becoming a common way to reduce nu trient discharges to coastal and surface water bodies. However, storage of efflu ent is needed in the wet or winter season to protect both coastal or surface waters and groundwater from contamination and supply irrigation in the dry season. Surface water dams are normally expensive. If the effiuent is given appropriate treatment, inj ection and extrac tio n wells can be used to restore saline and brackish aqui fers. Known as Aquifer Storage and R ecovery (ASR ), this system combines wate r that woul d otherwise be wasted with an unproductive aqui fer to add valu e to both. However, success relies on a thorough understanding of subsurface processes. Some questions to be addressed are: • can the existing quality of grou ndwater be adequately protected? • will the qu ali ty of the recovered wate r be fit for its intended use? • how can clogging of the injection well be prevented? • how much can be stored? • is it economic? • does it really work? This paper ou tlines a m ultidisciplinary research proj ect to assess techni cal viabili ty, environme ntal and commercial/ sustainabi lity economic feasibility of ASR at a site near Bolivar, Adelaide's major wastewater treatment plant (WWTP). The project team seeks to extend this work to other sites and expand the range of applications and scientific knowledge of aquifer processes.
groundwater pressures have continued to fall i n two confined aquifers and the salinity of this groundwater is increasing du e to localised leakage of more saline water from overlying and unde rlying brackish aquifers and ingress from more sa[jne parts of the same aquifers. At the same time, expanses of seagrass beds in the Gulf of St Vincent have been steadily depleted and th e Adelaide population is thought to have been a contributor to this through the discharge of secondary-treated effl uent and stormwater to the sea. The largest of the wastewater treatment plants, at Bolivar, is near the horti cultural irrigation area where groundwater is overexploited. U ntil recen tly thi s plant discharged approximately 40 GL/year of secondary-treated effluent to the sea. Some effiuent is being used locally for irrigation, but the Virginia Pipeline Scheme has recently been established to facilitate further growth in the irrigation industry. A new plant at Bolivar takes secondary- trea ted effluent (afte r its retention in oxidation lagoons) and, by dissolved air flotation followed by filtration and chlorination, produces recycled water which is fit for unrestricted irrigation use. About 100 km oflow pressure pipeline will re ticulate the recycl ed water to the horticultural area (see Figure 1). Over summer the irrigators will take all the available recycled water, but in
Key Words Artificial recha rge , water re use, health risk, water reclamation, groundwater
Introduction On the Northern Adelaide Plains licensing has restricted grou ndwater extraction for a thriving Au$40 million a year horticulture industry to about 18 GL/year. In spite of this restriction,
winter there will be surplus water. To continue irrigation with recycled water w hen rainfall exceeds plant water requireme nts would be wasteful and would result in excessive leaching of nitrate to shallow grou ndwater (S now et al., 1998; Snow and Dillo n, 1998). If this winter surplus can be stored and recovered for su mmer use it would enable th e irriga tion area to expand and result in almost zero effiuent discha rged to the sea. In this flat coastal plain the costs of a surface storage are prohibitive. H owever, in the aqui fe rs used to supply irrigation water there are brackish zones which are normally unusable but which could be used for storage of this good quality recycled water. Stormwate r ASR has genera ted water supplies for landscape irrigation in urban areas by harves ting the stormwater from detention ponds and wetlands constructed fo r flood mitigation. Single injection and recovery wells are preferred because ambient groundwater quali ty is not fit for irrigation and recovery assists with well redevelopment. R esearch and developmen t at a stormwater ASR site (Andrews Farm) on the Northern Adelaide Plains and its application at several other sites have bee n described by Dillon et al. (1997). As discussed below, the issu es faced in ASR with recycled water are more extensive and warrant comprehensive evaluation to mitigate risks and build an understanding which, if successful , will allow this technology to be applied elsewhere.
' ,,,/ / ''• / ,,
Figure 1 Northern Adelaide Plains map
T he Bolivar recycled water aquifer storage and recovery research project commenced in July 1997 with the constructi on of a test well at Bolivar and a series o f laboratory and desktop studies. Based o n these results, the second stage involves a trial injection and recovery of recycled water at a single well-instrumented test site near Bolivar, commencing in w inter 1999. If this is successful it will provide the information necessary for the design of WATER SEPTEMBER/ OCTOBER 1999
WASTEWATER a full- scale scheme capable of storing and recovering 5 to 10 GL/year. The project aims to evaluate the public health, environmental, technical and economic viabili ty of using an aquifer to store recycled water. An outline of the project in relation to t he Virginia Pipeline Scheme is given by Bosher et al. (1998). The benefits of these projects include: protecting groundwater supplies against further sali nisation, e nhan cing groundwater supplies, reducing nutrient-rich d ischarge to sea and more efficient use of water resources in an area where water has been a limit to economic growth.
9 chambers p er assembly
Figure 2 Diffusion chambers used in in-situ
In a series of public meetings the pathogen inactivation studies (from Pavel ic local community raised a number of et al., 1998a) issues. In order of importance to the local community, these inter-related • aquifer storage capacity being inadeissues are : public health, environment quate for economic ASR. protection, water resources management and technical/economic viability. Injected Pathogens. Bolivar recycled Steps in managing risks include: identi- water will be filtered and chlorinated fying and evaluating exposure and and pathogen concentrations will be so hazard, developing and implementing low as to allow unrestricted use for preventative m eas ures, d eveloping irrigation (target< 1 pathogen per 50 L). contingency plans and providing H owever, the question arises that if accurate, understandable and tim ely pathogens were present in the inj ectant, information to the community that for example due to a process failure at could potentially be affected. the treatment plant or recontamination, The broader issues associated with what would become of them in the water recycling and reuse have been fully aquifer? explored by many researchers (Asano, Pavelic et al. (1996), Dillon (1996) 1998). In co mparison with typical and Toze (1997) reviewed the literature stormwater at Andrews Farm, recycled concerning the survival and viability water has higher nutrient and organic of pathoge nic micro-organisms in concentrations, higher partial p ressure of aquifers. Numbers of o rganisms CO2 and, like stormwater, a possibility of commonly decline at an exponential containing pathogenic microorganisms. rate (analogous to radioactive decay) . However, there is greater control on the T he time over which the number of quality of water. This has been seen in viable organisms declines to 10% of the the USA as a reason for p referring number initially present is called the recycled water to stormwater fo r artificial removal time. Five species of enteric recharge intended to create potable water bacteria had removal times of 3 to 33 supplies (NRC, 1994). M ost ASR sites days. Six independent laboratory and in the USA have been constructed for field studies of E. coli survival in potable water supplies with potable or groundwater found removal times of 3 near-potable source waters (Pyne, 1995). to 20 days, with a mean of 5 days and Ri sks identified for the Bolivar ASR median of3.5 days (Pavelic et al. , 1996). proj ect and on whic h the project The same studies fpr faecal Streptococci focu sed were specifically related to had removal times ranging from 3 to 33 subsurface processes and include the days with a mean of 10 days and median of 4.3 days. Viruses and coliphages had a possibility of: • growth or survival in the aquifer of similar range of removal times, wi th sp ecies of Poliovirus, Coxsackievirus, inj ected pathogens • growth of opportunistic pathogens Echovirus and Rotavirus having removal times of between 3 and 33 days (from indigenous to the aquifer • inj ected water reaching existing nine studie s) and various coliphages between 1 and 7 days (from four studies). water supply wells Information on protozoan inactiva• irreversible clogging of the well or tion in groundwater is scant. A preliminearby aquifer • well or aquitard instability due to nary study by Ragusa et al. (1998) in the T2 aquifer at Andrews Farm found that aquifer dissolu tion or pressure changes • recovered water containing an exces- for two species of Giardia (intestinalis sive proportion of brackish native and muris) removal times ranged from 7 to 23 days. groundwater 22
WATER SEPTEMBER/OCTOBER 1999
Removal rate depends primarily on the p resence of antagonistic organisms and on temperature, with highe r tempe ratures accelerating removal. Pavelic et al. (1998a) developed a diffusion c hamber met hod to quantify pathogen inactivation in groundwater in-situ (see Figure 2). T hey found that the presen ce of aquifer medium prolonged survival with re spect to that measured in chambers containing only water. Poly merase chain reac tion (PCR) techniques to quantify protozoa and viruses are currently being d eveloped in order to estimate more accurately the survival times of these o rganisms should they reach the aquifer via the injected recycled water. R esidence time within the aquifer is the key to the fate of any injected pathogenic organism. When residence time of i1~ectant in the aquifer exceeds several removal times, the viable n umbers remaining are orders of magnitude smaller than in the injected water and the risk of exposure to pathogens in recovered water is commensurately small. In most European countries, a 50 to 60 day residence time in the aquifer is used as a basis for establishing groundwater protection zones (van Waegeningh, 1985) in order to protect drinking water supply wells in u nconfined aquife rs against pollution by pathogenic organisms. For th e larger micro-o rganisms, such as protozoa and helminths, with a size similar to the dimensions of the pores of the porous medium, removal can also occur by filt ration during passage through the aquifer. However, for ASR projects where recovery takes place from the inj ec tion well, no allow ance can be made for passage through the aquifer. The first water extracted during recovery may need to be stored and recycled to avoid the potential for retic ulation o f water containing pathogens which may have been shielded in well biofilm stripped off at the start of the recovery cycle. Indigenous Pathogens. Opportunistic pathogens are ubiquitous in aquifers, even those which are well protected fro m human activities. Aeromonas hydrophila, Pseudomonas aeruginosa and P. stutzeri, Yersinia enterocolitica and various Flavo- bacterium species are co mmonly detected as members of natural mic robial commu nities in many different environments, including groundwater. They have been implicated in a range of diseases and infections, particularly in very young, old, ill, or immuno-compromised people. W hen nutrient-rich recycled water is i1~ected, does this promote the growth of such potential pathogens, enabling them to be concentrated in th e recovered water?
WASTEWATER production well
; ; 0.3
CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ CJ
0.2 0.1 0 0
Figure 3 Cross-section diagram of total dissolved salts of groundwater at Bolivar assuming a well connecting T1 and T2 aq uifers
Seven ty-one bacterial species were isolated (17 from core material and 54 from native groundwater) at the Bolivar site. Of 16 identified strains, ni ne were recognised as opportunistic pathogens and the p athogenic status was unclear for a furt her three. Laboratory studies have been conducted which found that growth rates for Pseudomonas aeruginosa were no different for groundwater and mixtures of recycled water and groundwater. While further tests are required to substantiate this and expand the range of micro- organisms tested, current re sults are en couraging and suggest that this issue will be manageable. If absence of regrowth is shown, there would b e no need to disinfect recovered water, as its pathogenic status would be at least as good as the chlorinated inj ectant, with the possible exception of the first water recovered (as ou tlined above). Leaky Wells. A 7.5 metre thick clay aquitard separates the brackish aquifer (T2, 2100mg/L) which is the target for injection of recycled water from the overlying fres h wa ter aquifer (Tl, 800mg/L) which is used fo r irrigation, stock and domestic purposes (Table 1). In this area w here there is no re ticulated potable supply, many people use their wells for drinking, cooking and bathing water. An examination of drilling records, site visits and information volunteered at community meetings led the project team to evaluate the
Figure 4 Hydrau lic cond uctivity variation of aquifer materia l in laboratory columns (from Rinck-Pfeiffer et al., 1998)
prospect of a leaky well connecting the two aquifers within a kilometre of the injection well. While the re is n o evide nce that su ch a well exists, the possibility could not be excl uded. Simulations were condu cted using a 3-D FEFLOW model, assuming a large perforation through the clay at 400 m from the injection well and, for sim plicity, presuming that both inj ec tion and extraction from a nearby drin king/ irrigation well were continuous at their maximum rates fo r 10 years (see Figure 3) . This is a gross exaggeration of the flow rates and the hydraulic heads and velo cities in the aquifer and ignores the recovery cycle. The simulation assumes the T2 aquife r is he teroge neo us in layers with the highes t hydraulic condu ctivi ty in the layer immediately below the Munno Para Clay. Again, this is a worst case scenario for the possibility of inj ec ted water reac hing the production well. R esults indicated that upward leakage from the more saline T2 aquifer would give a small increase in salinity at the production well in the first year and this would then stabilise as the T 2 aquifer was freshened by injectant (1200mg/L). However, it would take more than six years continuous injection and pumping before the first trace of inj ected recycled water would appear at the drinking water well and this would increase in time to stabilise after 30 years to contribute less than 1% of the wate r pumped from the well. If pathogen attenua ti on 1s as
expected, the travel time to a drinking water w ell will en sure tha t the recovered wa ter meets drinking water guidelines for any mi cro-organisms origina ting from the injection trial. Any con servative solutes in wa ter (including recycled water) leaked from aquifer T2 or displaced from the aqui tard that may lie ou tside drinki ng water guidelines will be sufficiently diluted that the well water w iU meet drinking w ater guidelines. The adsorptive capaci ty of the aquifer provides an additi onal factor of safety, which for this aquifer is significant for some pollutants such as metals and some organic ch emicals (Olive r et al. , 1996). In reality, with summer recovery from the injection well, th e time scale for injected water to reach the drinking wate r well will be substantially longe r and the proportion of injectan t recovered would be lower than in this sim ulation. While this is a worst-case scenario, it was worth explo ring this to put an envelop e on the po te ntial exposure to recycled water in drinking supplies and provide the local community with a more accurate understanding of risk than otherwise would be p ossible. These modelling predictions will be verified during th e trial using a network of monitoring wells in the vicinity of the inj ectio n well. M ost are in the target aquife r, but one is in the overlying aquifer that is used as a drinking water supply. Grou ndwater pressures will be
Table 1 Lithology of Bolivar recycled water ASR site (after Martin et al., 1998) Llthologlcal unit Recent Hindmarsh Clay Ca risbrooke Sand (Aquifer Q4)
Contains saline aquifers (>5000 mg/L)
Dry Creek/ Hallet Cove Sand (Aquifer Tia) Upper Port Wlllunga Formation (Aquifer T1b)
Munno Para Clay
Lower Port Willunga Formation (Aquifer T2)
Target for injection (2130 mg/L)
Drinking and 1rrigat1on water (800 mg/L)
Low yielding marl
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WASTEWATER (cont. from p . 23) monitored, grou ndwater samples will be taken according to a monitoring program and in selected wells indicators of the presence of injectant will be continu ously recorded . This w ill provide definitive information on the way i njected water moves in the aquifer. Furthermore, nearby drinking/irrigation wells have been sampled and analysed prior to the injection trial and will be resampled during the trial to provide additional assurance to the local community on the protection of the quali ty of their water supplies. Clogging. Clogging of injection wells
has been a maj or problem in the past and un til a good understanding evolved of the processes w hich cause clogging, injection wells were regarded by many as unviable. T he major causes are: • physical clogging by suspen ded solids an d organic matter • chemical clogging by precipitation o f minerals on the surface of aquifer materials • biological clogging due to growth of micro- organisms and associated polysaccharides • gas binding thro ugh release of entrained air o r production of gases • dispersion of clay minerals or rearrangement of fine material in the aquifer. Various forms of pre-treatment of the injectant can reduce the incidence of clogging an d periodic redevelopmen t o f the injection well can help to mai n tain acceptable inj ectio n ra tes . Improved design of injection wells and development techniques has also assisted in overcoming clogging problems. Due to low suspended solids and high nutrient status of the injectant, it was considered that biofilm growth in the well would be the most im portant clogging process at Bolivar. Experiments were conducted using cores of aquifer material, which, under anaerobic conditions, had been stored, ground, sieved and used to pack three laborato ry columns. A small laboratoryscale treatment process was built to replicate the water quali ty expected from the final DAF/ F plant and was fed with secondary-treated water taken from Bolivar oxidation lagoons. T he output water quality was similar to that of an earlier pilot DAF/ F plant and was used to supply water that was passed through the three columns at a constant rate of flow for 23 days. The experiment is described in more detail by Rinck-Pfeiffer et al. (1998). An initial reduc tion in hydraulic conductivity was observed over the first week, as expected , after which i t remained approximately co nsta n t or increased (see Figure 4). T he hydraulic 26
WATER SEPTEMBER/ OCTOBER 1 999
be possible to predict th e resultant partial pressure of CO 2 and therefore the potential for calcite dissolution . While this process is slow and helps to offset the effects of well clogging, it could ultimately destabilise the well and even compromise the integrity o f the overlying aquitard by undermining it in the vicinity of the injection well. Geotechnical studies were perfo rmed to evaluate the shear an d tensile strength of the clay aquitard and to determine the possible failure mechanisms. The pressu re diffe rence (most critical during recovery) across the aquitard required to cause its failure u n de r differe n t support condi tions could then be estimated. In this way it is intended to determine th e safe operating life of an injection well fo r various pressures across the aquitard. This will be validated during the trial by observing calcium and bicarbona te concentrations of injected and recovered wate r to assess the mass of calci te dissolved, by observing the quantity of sand recovered from the well and by recording any vertical movement o f the clay layer near the injection well. It is important t hat the aquitard retains its integri ty as a hydraulic barrier, to prevent the inte rconnec tion and mix ing of water between aqu ifers. If the aqu ife rs became connected an irreparable change in aquifer hydraulics would occur. T he ability to control the distribu tion of inj ectant would be lost lnstablllty. Groundwater and aquife r and the ability to protect the drinking ma terial are generally in a state o f water quality of the upper aquifer from c he mical equilib riu m in a confi ned inj ectant could not be assured. Thereaquifer system. H oweve r, wh en a fore, w hile aqui tard i mpairmen t is different wa ter is injected into t he considered highly improbable under aquife r, this equilibrium is disturbed good management of the site, monitorand geochemical reactions can occur ing will be un dertaken to give advance that result in dissolution of aquifer warning of any potential problems so material or precipitation of minerals in that these can be averted. In general, aquitards can be protected by restricting the vicinity of the injection well. As these processes can destabilise a well pressures d uring inj ection and well and result in excessive sediments in recovery to an acceptable range and by recovered water, or in clogging of the avoiding sites w here aquitards are thin well, it is important to be aware of or weak. them. O ther processes which may result in recovered water containing hydrogen Brackish Groundwater. The quality of sulphide or excessive iron or manganese recovered wate r depe nds to a large due to biogeochemical reactions also degree on the quality and amount of need to be understood (Rattray, 1998). water i1~ected and on the quality of T his allows precautions to be taken to ambient groundwater. In any recovery prevent suc h problems before t hey cycle, the proportion of inj ected water occur, such as adjusting the pH or redox in the recovered water decreases with state of the injectant, or monitoring to time. If the ambien t groundwater is saline, there is a limit to the volume of determine the working life of a well. In a carbonate aquifer where surface water that can be recovered for i ts water is injected, an increase in the intended uses. The prop ortion of partial pressure of carbon dioxide as a recovered water that is of suitable result of oxidation of organic carbon quality for its intended use, as a fraction may assist in dissolving calcite in the of the injected volume, is called the aquifer matrix (see Figure 5, after recovery efficiency. Gerritse, 1998). If the amount of labile The recovery efficiency depends on organic carbon that would be oxidised the homogeneity of hydraulic properin the well could be quantified it would ties of the storage zone. Factors w hich
conductivity decli ne was most p ronounced in the fi rst 3 cm at the inlet end of the column due to physical and biological clogging. H owever, after about 15 days, the permeability of this zone began to increase due to calcite dissolution in the matrix material in this zone. Similar observations have been made in the field where stormwater was injected into the same aquifer at Andrews Farm (Pavelic et al. , 19986). It vvas considered that relatively frequen t redevelopment of the well would be needed to prevent clogging and that clogging would be reversible with such redevelopment. Independent tests on hydraulic conductivity of intact aquifer core material were undertaken using a triaxial cell apparatus which could maintain p ressures at 1.2 MPa to approximate the condition of the material in- si tu. Variations o f hydrauli c condu ctivi ty over several orders of magnitude were observed in the aquifer. T he hydraulic condu ctivi ties o f intact cores were smaller than in the repacked columns, so it is anticipated that the ini tial hydraulic conductivity decline in the well may be more severe than the colum n tests indicate. H owever, the fi ner calcite cemen ted matrix is expected to be amenable to dissolution and the column study results may best represent the ultimate hydraulic conductivi ty of the well perimeter.
WASTEWATER improve recovery efficiency include future, in determining admissible 300 ,---~-----....,---....,-_-_-_-__ - _ - ~ - - - - - - -- , increasing the volume of injectant, sites for ASR with recycled w ater in -+- %Ca: Calcite+Dolomite IEh, _200 mV I --- %Mg: Calcite+Dolomite increasing the number of years of order to obtain the necessary sto rage -l!t- %Ca: Dolomite 200 operation of the site, avoiding capacity w hile protecting ground%Mg: Dolomite %Ca: Calcite very saline groundwater, avoiding water quality for all existing water "' aquife rs which are karstic or have users on the Northern Adelaide Plains. "' 100 ~ strongly developed secondary porosHaving discussed the risks for the ~ c.. ity and being aware of aquifer Bolivar recycled water ASR research stratigraphy so as to judici ously project, it is timely to review precipitation i management guidelines for ASR. select target intervals for injection. R eliable predictions of recove ry Âˇ100 - ~ - ~-,.-~---~-~~-~----< ASR Management efficien cy depend on field trials and .3 -4 -5 -2 Âˇ1 (a) pCO, Guldellnes on an understanding of aquifer heterogeneity (Gerges et al., 1998). Australian water quality guideFigure 5 Prediction of change in Ca and Mg in A range of techniqu es has been laboratory columns eq uilibriated with recycled lines for aquifer storage and recovery employed to determine variations in water. Results of PHREEQE modelling (Gerritse, of stormwater and recycled wate r hydraulic conductivity in the T2 1998). Arrows indicate the partial pressure of CO 2 have been produced (AWRC, 1982; aquifer at Bolivar. Intact cores have in the atmosphere (a) and in the leached columns Dillon and Pavelic, 1996). The latte r of aquifer material (b) been tested in a triaxial cell using followed literature reviews of inte ra n ovel technique to measure national guidelines and practices hydraulic conductivity in vertical and inj ected wate r has not flowed out this (Pavelic and Dillon, 1997), field studies h orizontal directions . The results far, rather i t displaces aquifer water in of stormwater recharge at Andrews indicate that at the scale of core samples, the vicinity of the injection well and Farm (Dillon et al., 1997) and were t he aquifer mate ri al is generally because the system is confined, pressure based on the principles of the National isotropic, i.e. horizontal and vertical increases rapidly propagate radially Water Quality Management Strategy hydraulic conductivities are similar. ou twards. The pressure gradient causes (NWQMS) (Dillon and Pavelic, 1998). H owever, these vary by seve ral orders of the ambie n t groundwate r to flow In summary, the guidelines recommagnitude over the aquifer thickness. It outward to accommodate the injected mended that the quali ty of injectan t appears that anisotropy and hydraulic fluid . While increasing the volume of should preserve all potential beneficial conductivity variations in the aquifer groundwater in storage is a primary uses of the existing groundwater. In are mostly at a scale which exceed s the benefit for over- exploited aquifers, it is keeping w ith NWQMS groundwater dimensions of sections of core, but are expected tha t in general the major protection guidelines (NWQMS, 1995) somewhat smalle r than the aqu ife r benefit from ASR will be replacing this offers a higher level of protection to thickness. This work is to be confirmed ambient brackish or degraded ground- aquifers containing higher quali ty wate r wi th down- hole electromagnetic (EM ) water with water of usable quality. That or discharging into e nviro nmentally flow metering and the analyses of is, aquifer restoration and groundwater sensitive waterbodies. The guidelines aquifer pumping test results. D own- quali ty enhancement may be the main also allow for attenuation p rocesses hole geophysical logs are also available value-adding functions of ASR. On w he re these are quantified in the (Martin et al., 1998) to test for co rrela- recovery, aquifer pressures decline and aquifer. Codes of practice are currently ti on between EM flow meter and water is released from storage. To avoid being developed by the SA Artificial geophysical properties . The fate of the possibility of aquifer compaction R echa rge Coordinating Committee. injected water in the aquifer will be and loss of storage and transmission If the aquifer is brackish, the water determined making use of piezometers capacity a confined aquifer would n ot injected need not be fit fo r drinking, so w ith water pressure and water quality normally be depressurised so that it long as all existing potential beneficial sensors and recorders during the trial. became unsaturated. uses, say irrigation, stock use and At the Bolivar ASR trial a series of ecosystem maintenance, are protected. R esults from these will be compared with elec trical resistan ce cross- hole aquifer pumping tests will be performed If the injectant does not meet NWQMS tomography results, reco rded using w ith piezometers in place to determine water quality guidelines for chose apparatus specially d eveloped for this th e aquifer hydraulic c harac teri stics beneficial uses, the at tenuation of p roject. Again FEFLOW solute trans- which would enable an evaluation of contaminants within the aquifer would port modelling will be performed, to the potential storage capacity and the need to be quantified to ensure that the compare with observations and to refine best way to manage this. Recharge rates required water quality is achieved at all the aquifer hydraulic characte risation of 20 L/s are exp ected, enabling inj ec- prospective extraction wells. If there are tion of around 200 ML per well each drinking water users in fres he r parts of and predictions of recovery efficiency. winter. If this is achievable, about 50 the same aquifer, an evaluation would Inadequate Storage Capacity. While wells may be needed to recharge the full be required on whether contaminants confined aquifer systems 0ften contain volume of winter discharge of recycled would have attenua ted to drinking huge quantities of water, they have only water from Bolivar. There w ill be a water standards within the minimum a finite capacity to store additional minimu m economic recharge rate travel time co such wells to ensure they water. For example, a porous aquifer above w hich t h e investment in a are not compromised. These gu idelines 50 m thick with a typical porosity of recharge well will be repaid by the value are quite different to those currently 20% may contain 10 m water (10 GL/ of the water recovered. If clogging is applying in USA w here groundwaters sq km) . However, if the hydraulic head severe or hydraulic interference bet- less than 10,000 mg/L TDS are considcan be increased by 20 m, the additional ween injectio n wells is excessive, ered to be potentially potable and water elas tic storage (for a typical storage recharge rates may also decline. A trade- needs to be treated to drinking water coefficient of 5 x10- 4) is only about off between treatment of water and standards prior to inj ection (with few 10 mm water (10 ML/ sq km). In trans- sustainable recharge capacity is expected exceptions) (National Research Council, mi ssive aquifers the pressure increase is and this will be explored further at 1994; WEF & AWWA, 1998). observable a number of kilometres from other sites. T he fa te of injected water Community awareness is an importhe injection well. Of course the needs to be taken into account in tant aspect of the development of artifi-
WATER SEPTEMBER/OCTOBER 1999
WASTEWATER cial recharge projects. Just as the community should be consulted in defining the beneficial uses for which each of their aquifers should be protected, there needs to be a process of informing and edu cating t h e community about groundwater and the risks and benefits involved in artificial recharge. From the Bolivar example above there are some co ncepts which are not immediately intuitive. One of the tasks of professionals is to help the community gain the understanding necessary for them to make an informed assessment of risk. Undertaking investigations in stages, such as for the Bolivar project, where laboratory work defined the risks before field trials began, may be helpful in building confidence in methodology and capacity to manage the project, as well as allowing relationships to develop.
Conclusions Storing recycled waters in aquifers can produce significant benefits for water re sources development and management. ASR may help to offset the costs of treating efiluent for protecting the quality of receiving waters, while expanding the quantity of water supplies for irrigation, restoring otherwise unusable aquifers and supporting over-exploited aquifers. It can provide an alternative to new dams when only moderate quantities of water need to be stored. However, there are risks in storing recycled water in aquifers and in the case of the Bolivar ASR trial, there has been a substantial investment in research to identify and manage these risks. Aquifer storage and recovery is not a form of waste disposal. It requires a sound understanding of the hydraulic and geoc hemical characteristics of aquifers and of the physical, chemical and biological processes occurring within them. This knowledge underpins the management of ASR operations to contain the risks of failure due to public h ealth, environmental, technical and economic factors. There is no substitute for experience with ASR, particularly if that experience is strongly linked to supporting research on the key risks at any site. Sufficient preliminary work has been undertaken at the Bolivar site to demonstrate that no drinking water wells will be adversely affected by a trial injection and recovery sequence. T he work has also led to the development of a monitoring program including the quantity and quality of water to be inj ected and recovered, 28
WATER SEPTEMBER/OCTOBER 1999
pressure and quality of groundwater in monitoring wells in the T2 and Tl aquifers, measurements of pathogen inactivation rates and fate of indigenous opportunistic pathogens, monitoring of any vertical movement of the aquitard and geophysical measurements to interpret the spatial distribution of injectant in the aquifer. This will enable testing of laboratory-based predictions at field scale and provide feedback to ensure these risks are managed effectively. Experience gained through substantial research investments in ASR with stormwater (at Andrews Farm and other sites) and with recycled water ASR (at Bolivar) is expected to pave the way for wider applications and for future research on artificial recharge. This would include producing d rinking water supplies from potable and nonpotable source waters, using soil aquifer treatment, bank filtration and injection and recovery using different wells. In some cases ASR may be a precursor to these types of artificial recharge which may offer greater assurance on subsurface water treatment. For ASR, the quality of the injectant is expected to ultimately dominate the quality of recovered water and so long as the injectant meets all the water quality criteria for the beneficial uses of the ambient groundwater and is not aggressive, it is unlikely to create health or environmental hazards. In general, ASR has potential for producing supplies in brackish, saline or polluted aquifers, where injectant pre-treatment costs are lower than for drinking water supplies and the new supplies produced could not have been met by the existing aquifer. In essence t his is aquifer restoration, where in a few years fresh water supplies, say for irrigation, can be developed in aquifers which have been saline for millennia.
Acknowledgements This work has been reported with permission of the Steering Committee of the Bolivar ASR Research Project. T h e project partners are CSIRO,
Primary Industries and Resources SA, United Water Int. Pty Ltd, Sou th Australian Water Corporation and SA Department of Administrative and Information Services. Natural H eritage Trust support for this project is gratefully ackn owledged. The authors thank Bryan Harris, Borvin Kracma n, Pascale Sztajnbok, Chris Basher, Robert Thomas, Lester Sickerdick, Margaret Dugdale, Professor Stewart Greenhalgh, Dr Robert Gerri tse and staff of PIRSA, CSIRO and the Australian Water Quality Centre for their contribu tions to the direction and execution of this project. David Williamson and Andrew Speers also made helpful comments on a draft of this paper.
References Asano T (Ed.) (1998) Wastewater Reclamation and Reuse, Vol. 10, Water Quality Management Library, Technomic Publishing Co, Lancaster, Pennsylvania, 1528 pp. Australian Water Resources Council (1982) Guidelines for the Use of R eclaimed Water for Aquifer Recharge. Water Management Series No 2. Aust. Govt Publishing Service, Canberra. Bosher C B, Simms T O and Kracman B (1998) Wastewater Aquifer Storage and R ecovery (ASR): Towards Sustainable Reuse in South Australia. In Artificial Recharge of Groundwater, Peters et al. (eds) Balkema, Rotterdam, pp. 87-92. Dillon P J (1996) Groundwater Pollution by Sanitatio n on Tropical Islands: A UNESCO IHP Study. Centre for Groundwater Studies Report No 66. Dillon P J and Pavelic P (1996) Guidelines for the Quality of Stormwater and Treated Wastewater for Injection into Aquifers for Storage and Reuse . Urban Water Research Assoc. of Australia, Research Report No. 109. Dillon P , Pavelic P, Sibenaler X, Gerges N and Clark R (1997) Storing Stormwater Runoff in Aquifers, Aust. Water and Wastewater Assoc.]. Water, 24(4)7-11. Dillon P J and Pavelic P (1998) Environmental Guidelines for Aquifer Storage and Recovery: Australian Experience. In Artificial Recharge of Groundwater, Peters et al. (Eds.) Balkema, Rotterdam, pp. 313-318. Gerges N Z, Howles S R and Dennis K J (1998) ASR, Hydraulic and Salinity Response in Unconfined/ Confined Aquifers. In Artificial Recharge of Groundwater, Peters et al. (Eds.) Balkema, Rotterdam, pp. 269-274. Gerritse R G (1998) Biogeochernical Changes in Aquifers from Injected Waste Water. CSIRO Land and Water Report No. 16/98. Martin R, Sereda A and Gerges N (1998) Bolivar Reclaimed Water Aquifer Storage
WASTEWATER and R ecovery T rial: Progress R eport 1. Primary Industries and R esources Report No: DME 149/95. National Research Council (1994) Groundwater Recharge Using Waters of Impaired Quality. National Academy Press, Washington DC. National Water Qual.ity Management Strategy (1995) Guidelines fo r Groundwater Protection in Australia. Agriculture and R esource Management Council of Australia and New Zealand and Australian and New Z ealand Environment Conservation Council. Oliver Y M, Gerritse R G, Dillon P J and Smettem K RJ (1996) Fate and Mobility of Stormwater and Wastewater Contaminants in Aquifers: (2) Adsorption Studies for Carbonate Aquifers. Centre fo r Groundwater Studies R eport No 68. Pavelic P, Dillon P J, Ragusa S and Tozc S (1 996) The Fate and T ransport of Microorganisms Introduced to Groundwater T hrough Wastewater R eclama tion. Centre for Groundwater Stud.ics R epo rt No. 69. Pavelic P and Dillon P J (1997) R eview of Internationa l Experience in Injecting Natural an d R eclaimed Waters into Aquifers for Storage and R euse. Centre for Groundwater Studies Report No. 74. Pavelic P , R agusa S R, Flower R.. L, RinckPfei ffer S M and Dillon P J (1998a) Diffusion C hamber Method fo r In Situ Measurement of Pathogen Inactivatio n m Groundwater. Water R esearch, 32(4)1144-1150.
Pavelic P, D illon P Barry, KE H erczeg AL, R attray K J , Hekmeijer P and Gcrges N Z (19986) Well Clogging Effects D etermined from Mass Balances and Hydraulic R esponse at a Stormwater ASR.. site. In ArtiEcial FZechargc of Groundwater, Peters ct al. (Eds.) Balkema, Rotterdam, pp 61 - 66. Pyne R.. D G (1995) Groundwater R echarge and Wells: A Guide co A quifer Storage and R ecovery. CRC Press, Florida. R agusa S R , Flower R.. L P , Dillon P J and Pavelic P (1998) Measurement of Pathogen Inactivation in Artificially R echarged Stormwatcr. fn Proc. !AH Intl Groundwater Conf.: Groundwater Sustainable Solutions, M clb, Feb 1998, eds TR. Weaver & C R.. Lawrence pp. 545-550. Rattray K J (1998) Geochemical Reactions Induced in Carbonate Bearing Aquifers Through Artificial Recharge. MSc Thesis, School of Earth Sciences, Flinders University of South Australia. Rinck-Pfeiffer S, Ragusa S R.., Vandervelde T (1998) Column Experiments to Evaluate Clogging and Biogeochemical R eactions in the Vicinity of an Effluent Injection W ell . In A rtiEcial R echarge of Groundwater, Peters et al. (Eds.) Balkema, R otterdam , pp. 93-98. Snow V 0 , Dillon P J , Smith C J and Bond W J (1998) Containing the Risks of Groundwater Contamination from R euse of Effluent. Proc. 6th NSW R ecycled Water Seminar, pp. 66-72, Aust. Water and Wastewater Assoc.
Snow V O and Dillon P J (1998) Australian Design Method fo r Sustainable Land Treatment of Rural Industry and Sewage Eilluent. Final Report on LWRRDC Project CWWl 7. Centre for Groundwater Studies Report No 82. Toze S (1997) M icrobial Pathogens in Wastewater. CSIRO Land & Water Tech. R eport No 1/97, 79 pp. Waegeningh van H G (1985) Overview of the P rotection of Groundwater Quality. IAH/IAHS Intl. Contributions to H ydrogeology, Vol 6, 159-166. Water Environment Federation and American Water Works Assoc. (1998) U sing R eclaimed Water to Augment Potable Water Resources. Special Publication by a Joint Task Force, 357 pages.
Authors Peter DIiion , Simon Toze, Paul Pavellc, Santo Ragusa , Martin Wright and Paul Peter work w ith
CSIRO Land and Water and Centre fo r Groundwater Studies (CGS), PMB2 Glen O smond SA 5064 , email Pete r.Dillon@adl.clw.csiro.au Russell Martin and Nabll Gerges are hydrogeologists w i th Primary Industries and R esources SA, Groundwater P rogram and CGS. Stephanie Rinck-Pfeiffer is a PhD studen t at Flin ders University on assignment from Generale des Eaux to CGS.
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Distinguishi ng between the abi lity of the majority (>90%) of the nitrogen 'bugs,' or soil microbes, and trees to transported from the Albany aerated dispose of the nutrient and particularly pond treatment plant to the tree farm the nitrogen content of tertiary treated and the trees and soil mop up whatever effiuent is one of the key aims of cu rrent is left. investigations at the Albany Tree Farm in Western Australia. A team of University of Western 30cm Australia (UWA) researchers compris.s:::: ing Mike Coote, Mi ke Kemp, Phil ii 60cm QJ Crock, Andrew Stilwell, Zuliang C hen a and Mark Adams is worki ng with a range of new techniques at the 550 ha 100cm site, where some 14 ha of pasture and 0 2 4 12 6 8 10 230 ha of trees are currently being irrigated with treated eilluent. 30cm This research, w hich is fu nded by the Western Australian Water Corporation .s:::: and began in 1996, is the first Australian ii 60cm QJ a test of the ecological effectiveness of a • Trees + effluent fully operatio nal system of land di sposal • Trees no effluent 100cm of effiuenc. The research is managed for a Trees reference the Corporation by Gunnar Horn and 0 2 4 6 8 10 12 overseen by a Steering Committee Nitrate-N (ppm) w hi ch includes Bob Sillifan t, Jane Oliver and Ivan Unkovich as well Figure 1 Nitrate concent rations in free soil representatives of the Department of water at differing depths Conservation and Land Management and Kinhill Consulting Engineers. Nitrogen Phosphorus No effluent 102 kg ha·1 No effluent 12 kg ha· 1 The UW A researchers are measuring • wood many attributes of the hydrological and Cl bark nutrient cycles at the Albany tree fa rm o twigs • branchwood and in particular, the rates of nutrient o deadwood uptake by the trees and the rates of • loaves J denitrification (the conversion of nitrate + effluent 192 kg ha· 1 + effluent 24 kg ha·1 to N 20 or N 2 ) by soil microorganisms. These two processes arc critical in determining the effectiveness of tree and pasture- based treatment systems in disposing of nitrogen. So far, it looks as if the bugs are Figure 2 Nutrient content of the trees after winning! Denitrification accou nts for three years of growth (not drawn t o scale)
The w hole land treatment process includes several stages. First, the trea ted wastewater is pumped to small holding dam s from where it is used to irrigate a large set of pasture bays. About 3-4 tonn es of nitrogen are added in this way to each hectare o f pasture each year. Secondly, runoff from the bays and its nutrient content collect in a furt her large dam before being filtered and finally used to irrigate the trees. Figure 1 sh ows how the nitrate concentrati on of the treated effiu en t is diminished as it filters down the soil profile in eac h stage of the treatment system. Concentration s in efflu e n t when it arrives at the tree farm are - 29 mg/L. Tn the main dam they are - 18 mg/L. At the Gunn Road monitoring point on the Seven Mile C reek, concentrations are less than 0. 7 ppm . It is worth noting that ni tra te concentrations in grou ndwater in many agricultural regions in the south-west of Western Australia are greater t han 5 ppm and in soil water greater than 2-3 ppm-much more than the conce ntratio n in water that percolates below a depth of l m at the Albany Tree Farm! At present, the trees are mostly four years old, with some a year older. By early 1997 the three-year-old trees had accumulated an extra 90 kg of nitrogen and 12 kg of phosphorus per hectare over and above the nitrogen and phosphorus accumulated by trees which were not irrigated with effiu ent (see Figure 2). The rate of application of nitrogen to the trees is rough ly 100 kg per hectare per annum, so accumulation of90 kg over three years is not too bad. WATER SEPTEMBER/OCTOBER 1999
ENVIRONMENT Nonetheless, the denitrifying soil ' bugs' are still doing the bulk of the work in removing nitrogen from the effiuent, although some nitrogen will accumulate in the soil in organic forms. Eve n tually these trees will be harvested. The nutrients will then be exported. The wood will be sold, with the return going towards meeting the running costs of the treatment system. In the long run, the financial return from the sale of wood might mean cheaper costs of sewage disposal for Albany residents. The research program has produced a number of u nexpected benefits. The UWA team and the memb ers of the Steering Committee have h elped develop new methods for measuring leaf area in plantations, for measuring drought and nutrient stress in plantations and for foliage sampling. These are now being published in the in ternational literature. T he other aim of the UWA team is to prepare an integrated management model of tree growth and the water and nutrient cycles at the Albany Tree Farm. The model will be user-friendly and suited to the purpose of optimising the ecological aspects of the treatment system as well as helping grow the trees for economic benefits. UWA and the
funding to continu e this important research via the Strategic Partnersh ips: Industry R esearch and Training grants scheme. Overall, the research and management teams remain confident that the Albany T ree Farm will be an ecologically sustainable treatme nt system-as well as an economical system. Unknown fac tors include the capacity of the system to retain nitrogen in the longer term. Nitrogen presently being retained in the soil can re- enter the system as nitrate if the nitrogen load becomes too great. Overseas, excess nitrogen loads have caused 'nitrogen saturation' of ecosystems with disturbing side effects. And, of course, we have to remember that the environmental costs of previous syste ms of disposal of effiuent were more than the community was willing to pay.
Authors UWA student Phll Crock collecting soll samples to measure nitrogen In soils at the Albany Tree Farm. Perspex chambers are used to measure rates of denltrlflcatlon
Water Corporation have also joined forces to apply for federal government
Dr Mark Adams is Associate Professor of the Ecosystem R esearch Group in the Department of Botany at the University of Western Australia, Nedlands WA 6907 . Jane Oliver is Plant Sup erintendant, Subiaco WWTP, Water Corporation, Western Australia.
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EFFECTS OF RADIATA PINE PLANTATIONS ON THE HYDROLOGY OF A SMALL CATCHMENT AT CROPPERS CREEK, VICTORIA L Bren, P Hopmans, D Flinn Abstract Project FO3 ('Croppers C reek') is a multiple ca tch me n t proj ect near Myrtleford 111 north- east Victoria examining the impact of radiata p ine plantation development on th e hydrologic ou tput of a 46 hecta re catchment. The proj ect is a rejuvenation of an older project that ran from 1975-1987 and involved clearing and converting the catchment to radiata pine. This project conti nues t he measureme nt usmg modern electronic field and advanced labo ratory chemical tech niques. Current work is looking at the water and nutrient balance, applyi ng concepts of sustainability and measuring the dynamic behaviour of stream flow. In general the results showed a strong, initial clearing effect, but this has died away over time and the hydrology of the cleared catchment now approximates that o f the ca tchment under native eucalyp t fo rest. Multiple catchment projects have the advantage of being directly field-based, but are a substantial cost in o rganisational commitme nt. However, we believe that such smallcatchment-based experimentation provides the best way of giving complete, sound knowledge o n the effects of forest practices on hydrology and, in the long term , resolving conflict.
Victorian age ncies had not been successful. The Victorian fo restry agency at the time, the Forests Commission Victoria, decided to launch a solid field project looking at the basis of small catchment hydrology and the infl uence of radiata pine. T hus was borne the 'Cropper Creek H ydrologic Project'-currently the cen trepiece of project FO3 of the CRC for Catchment Hydrology. This project involved selecting a trio of small catchments u n der native eucalypt fo rest. Gauging weirs and a network of measurement equipment were installed, studies of fundamental processes were underta ken and a knowledge of the behaviou r of the streams and stream water nutrients was gained (see Figure 1). The project took two years to install, with the firs t data being recorded in 1975. In 1980 one of the catchmen ts had its vegetation changed from native eucalypt fo rest to radiata pine plantation. Gauging continued until 1987, when the project was discontinued following a depa rtmental review. Data analysis con tinued and the project data
Introduction The Croppers C ree k Multiple Catchment Proj ec t exa mining the impact of radiata pine development on wate r resources had its origins in the mid-1970s. Then, as now, there was concern by downstream landholders at the im pact of radiata pine on local an d regional water use rs. Rad iata pine plan tations were being rapidly expanded, largely through the clearing of native forests. Afte r some very wet years, downstream landholders expressed considerable disquiet about the effects of the new plantations, claiming increased sto rm flow and erosion. The difficulty was that there was little reliable data with w hich to examine these claims and attempts at collaborative hydrologic projects with
Figure 1 Water- a forest product-passing over the Clem Creek Weir
were full y analysed for the next decade, with the last publication from the old phase of data collection taking place in 1997 (Bren, 1997) and overlapping wi th the new project. Times moved on, t he planta tio n grew and two new hydrology concerns emerged. A couple of drought years and the question of 'excessive ru noff were replaced with concerns abou t reduced water yield from the mature plantatio ns. 'Blue-green algae' scares in major rivers caused concern about nutrient inpu ts. D evelopment o f new tools such as 'REALM modelling' raised questions such as, 'What is the inpu t of nutrien ts from this landuse?' Once again, there were no easy answers. If management was to be pu t o n a sound basis and contin ued disp utes avoided, a n umber of such information voids needed to be filled by quality measurement. The one measurement opportunity was the abandoned Cropper Creek Project. Although needing conside rable work, inspection revealed that the measu rement and road infrastructure were sou nd. Similarly, the personnel involved in the project in the past were all available and showed a commitment to being involved in a new project. The new project involved fo rming an alliance betwee n the CRC for Catch ment Hydrology (intellectual expertise), Forests and Wood Products R esearc h and Development Corpo rati on (funding and project manage me n t), Victorian Planta tions Corporation (now H ancock Victorian Plantations Pty Ltd- land owne rs and managers), The Centre for Forest Tree Technology (water chemistry and tree physiology expertise) and the University of Melbourne D epartment of Forestry (hydrology expertise, project management). A list such as this is necessary, but it blurs the considerable overlap of proj ect roles and expertise in carrying out the work. So the alliance was formed, the spiders were cleaned out of the old instrument housings and it was back to work at Croppers Creek. WATER SEPTEMBER/OCTOBER 1999
ENVIRONMENT Croppers Creek Project
water samples are ta ken at w eekly intervals for full chemical an alysi s. In addition , autom ated samples collect frequent samples during storm flow s. The re are also deep groundwater bores to facilitate fun dam ental gro undwa ter studies com mencing in 1999. All in all, the data gives quite a comprehensive suite of information abou t the hydrologic processes. Figure 6 shows an exam ple of the electronic outpu t of the in-strea m measurements of wate r quali ty. W ork is shared be tween the vari ou s partners and management is by a committee .
The Croppers C reek Projec t Betsy Creek is a m ultiple catchm ent project looking at t he hydrologic impact of radiata pine developm ent on w ater flows, catchm e n t dynamics and wa te r quali ty prope rties. T h e basis of a mu ltiple catc hm ent project is that two or more catchments are gauged for some years until knowledge of the hydrologic similarity ('calibrati on ') is obtained. One catchme nt is the n subj ected to a landu se Cropper Crttk change or specific trea tment ··-" (e.g. fertilisatio n) and on e or 1·."' more of the other catchments (' controls') effectively provide a real-time model of a ' natural' R,..,-diQ.l<h,- .n, ltaew,l1 J'iadn:a.Lh'-'1Jlo:c:ll The Old and the New catchm ent. Such st udi es are The proj ect is very much a ( I ] very effec tive bu t time/ / Stream, l'inel'lu!>tloM contin uation of the old . consuming and quite demandFigure 2 Com puter-generat ed view of t he proj ect showing Fortunately the old proj ect w as ing in logistics and resources . t he three catchments well docum ented and written Un derpinning this are a up in pap ers and bulle tins. T he numb er of fu ndamental studies ew proj ect would have been impossin the pine plan tation ca n be clea rly of on aspects o f regional hydrology (e.g. Bren and Leitc h , 1986) . The proj ect is seen. Ella C reek catchm ent (1 13 ha) is ble t o condu ct w ithou t th e ve ry located in the Black R ange, about 22 the m ain co ntrol ca tchment and has substantial in frastru cture and intelleckm sou th- west o f Myrtleford, Victoria remained un cha nged sin ce initial tual invest me n t in the old proje ct. in the ca tchme nt of the BufL1lo Da m . m easureme nt. A portion of this catch- Pleasantly, it has been possible to virtuFigure 2 gives a computer- generated ment can b e seen in Figure 4, to the ally use the skills of all m embe rs involved in the old p roject, although, view of the proj ec t and shows Clem right of C lem Cree k catchme nt. Betsy C reek ca tchment (44 ha) is an reflec ting the times, the skills have C reek, Ella C reek and Betsy Creek aux iliary control catchm ent and has also come from different organisation s and catchments. been used i n different ways. C lem Creek catchment (46 ha) w as remained unchanged. H owever, the new proj ect tend s to the catc hments are gauged by All converted fro m native eucalypt fo rest to radiata pin e in 1980. M easurem ent passing water through a 120° V-notch use (for better or worse) mo re modern com menced on the catchment in 1975 . w eir wi th w eir h eigh t recorded elec troni c m easurem ent tec hnology . Figure 3 shows the just-cleared Clem mecha ni cally and elec tro nically (see This has many advantages in data C reek. A riparian strip of eucalypt forest Figure 5). W ater level is recorded on display over th e older me thods, but 30 m either side of the stream was analogue recorde rs. At C lem and Ella tends to be not quite as reliable and retained at the time of clearing. The W eirs th ere is also elec tronic recording . m o re difficult to re m ove i nc orrec t slope vegetation was subsequently burnt Each site has a storage raingauge and a data sequences. The se nsitivity of our and the area planted. The catchment was tipping-bucke t raingauge recorded ch emi cal analysis u sing m odern fertilised and thinned in 1998 and is electronically . At C lem and Ella Weirs colorimetric an d I C P AES analytical scheduled for clea r- falling in abou t 2015. th ere is now also in-stream electronic tech niques has also gone up considerFigure 4 is an oblique aerial photo- recording of water , pH, conductivity, ably, bu t this poses i ts own se t o f grap h taken in 1998 . T he development temperature and turbidity. Base flow ques tions about how much accuracy is
Figure 3 Clem Creek catchment was converted to radiata pine in 1980
WATER SEPTEMBER/ OCTOBER 1999
Figure 4 Aerial view of Clem Creek catchment
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needed and what is an 'impo rtant' difference in nutrient levels. A consistent problem with both the old and the new projects has been the ve ry high quality of the water, which means that only the best instruments can be used . Thus for instance, recent failure of a flow cu t-off switch on an automatic sampler appears to be because the conductivi ty of the water is so low that the sensor did not recognise it was immersed!
What Was Found The old Cropper Creek project showed that the conversio n of a native eucalypt fores t to radiata pine did have substantial effects on the catchme nt hydrology in the short-term, but that the hydrology was not 'destroyed' or even dramatically changed. In particular: • clearing of the native eucalypt forest from the catchment slopes increased the storm runoff for the first few stonns in winter-spring. After that, the cleared and uncleared catchments behaved identically. The change was attribu ted to higher soil moisture storage in the cleared catchment slopes at the end of summer and appeared to last for seven years • the clearing slightly inc reased summer strean1flow • the levels of nutrients in streamwater from the Clem Creek catchment were substantially unchanged by the clearing but nutrient exports increased temporarily because the water yield was greater. There was a large seasonal and annual variation and this alone emphasised the difficulty of making gene ralisations about nutrient behaviour • both before and after clearing the
Figure 6 Exam ple of t he data record for a wet pe riod in 1997
water was of very high quality in chemical and physical terms. T he riparian zone plays an important role in the protection and maintenance of water quality • peri odically large storms (perhaps every 20 years) generated flows with the ability to mobilise stream beds in both natural forests and plantations and these led to substantial sediment movement. Beca use such storms are uncommon o u r observations are scant bu t the mechanism of movement seems to be that the flows e n train bed material. Mass movement of catchment material downslope seems uncommon in this environment • in general there was little overland flow or surface ru noff on the catchment slopes, with most water infiltrating. Similarly, the actual soil appeared to play little direct role in the catchment hydrology, with most water movement occurring many meters below the 'soil' level and probably in the weathered, fractured rock zone of the catchment • the riparian zone appears to have a large role in the low flow water use. This is particularly manifested by the strong diurnal variation shown by flow from these small forested catchments. We feel that this question alone will provide interesting and im portant information, but we are also fi nding it a difficult area in which to obtain clear results • catchment 'soil' does not play a direc t role in the catchment wate r storage, but acts as a fas t conduit for infiltrating rainwater to deeper, weathered rock • many assumptions made concerning catchment behaviour tend to be
simplistic, incorrect, or do not adequately consider the natural spatial and time variation. Major results were presented in H opmans, Flinn and Fa rrell (1987), Leitch and Flinn (1986), Bren an d Papworth (1991) , Bren (1997) and many other papers.
Findings-Present and Future The current work co n tinues th e thrust of the old project with the aim of using more mode rn techniques to quantify the local e nvironment. In particular, the current project aims to : • give a water balance o f 17- to 20year- old radiata pine and examine the impact of a non-commercial thinning on radiata pine water use • examine the im pact o f radiata pine afforestation, thinning and fertilisation on the water quality of Clem Creek catchment. A commercial fertilisation of the catchment was carried out by helicopter in 1998 (see Figure 7). Analysis of data collected in a particularly large storm in September, 1998 is still in progress. However, data analysis up to August 1998 showed that the 17year- old radiata pine catchment had similar hydrologic characteristics to the eucalypt catchment which preceded it. Thus, as a working hypothesis, it would seem that the hydrologic distinction is not between radiata pine and pasture, but rather between forest (eucalypt o r pine) and pasture. We will be refining this conclusion in the next few months. Because of water shortages in 1998 this qu estion became of some economic importance, with farming groups suggesting that landowners should h ave WATER SEPTEMBER/OCTOBER 1 999
Figure 7 Spreading ferti liser on Clem Creek by helicopter
to pay 'rent' for water used by their crops. The chemical data collected shows similar characteristics to the pre-clearing data and although we still have some way to go in the analysis of this data, results indicate that the high quality of the water has been maintained. However, the work does and will go considerably beyo nd these aims.
Around the world multiple catchment projects have become a basic monitoring of the environment and this project is no exception. Thus the project data carry considerably more information thanjust the radiata pine effects and we are keen to formalise, encapsulate and use this information. Such projects also have been usefu l in giving 'depth' to courses in catchment hydrology and
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management by providing real, locally collected data and the opportu nity for students to collect their own data. It is intended to develop the project further to meet such aims. T he fi rst project extending the field data is using the Cropper Creek project to 'calibrate' a simple hydrologic model for 'native forest,' 'cleared' and '17- 20year-old radiata pine.' This model uses daily streamflow and temperature. The project will then use the accumulated weather records for Myrtleford from about 1890 to look at the occurrence and recurrence of drought and w hether a 'climate change' in soil moisture can be detected. A particular indicator of sustainability is the ability of streams to sustain flow in dry conditions and the work w ill quantify this indicator over this period. Additionally it w ill allow us to put the recurrent sequences of d1y and very dry conditions into a 'perspective,' see j ust how often such conditions are expected, rank major drought periods and to some extent correlate these rankings with anecdotal observations of drought- induced tree deaths on hillslopes. The second proj ect is looking further at the dynamics of groundwater inflow into the streams and diurnal variations due to day- night changes in evaporation. Groundwater storage and flow to the stream is the dominant hydrologic process in this environment at all times of the year. Notwithstanding our long involvement with the project, we still marvel at the abili ty of stream s to sustain flow for long periods without rain. In inspecting the data the most obvious variation is this daily change (see Figure 8). Such diurnal variation in stream wate r temperature and daily streamflow are a researcher's paradise. After storm fl.ow, they are the most apparent periodicities in the data and yield many subtle clues as to the hydrologic behaviour of the catchment slopes. We feel that there is considerable i nformation about slope vegetation water use carried in this signal by its shape, phase and amplitude, but this is not necessarily easy to extract. Work is continu ing a the me from the past p roject oflooking at the magnitude and p hase of this using newer tools and faster computers. In te restingly, our advanced techniques are also picking up a 'tide' in streamflow due apparently to the passage of th e moon arou nd the earth , influencing groundwater outflow. Again we can fi nd little information, either locally or internationally, on such behaviour and we are keen to explore this further since it is one of the most obvious manifestatio ns of catchment hydrology. Such projects also serve as substantial drivers for technical developmen t and these include developme n t of
ENVIRONMENT modelling techniques (currently excellent for ed ucatio nal a n d 22.s topographic-based), provisions tour pu rposes. We have used the S1rcam Wa1er zo.o of data se ts for other researchers, project area for one industry Tcmpcra1ure, 0c 17 .S reconciliation of stream flow and field day and intend to hold a direct measurem en ts of water series of these in the next two 15.0 use, development of laboratory yea rs. Howeve r, organisati o n 12.S methodo logies and examinaand condu ct of these is a tions of the efficacy of sampling substantial undertaki ng. and instruments fo r measuring. 2.0 Hourly Threats and W e have been disappointed in Stream Flow. 1,S Ls-I th e accuracy, precision and Opportunities reproducibility of in-stream 1.0 The Cropper Creek project m easure ments compa red to rep rese nts a major project and laboratory measure me n ts and comnl.itment. It does give us the this will also become a focu s of o pportunity to do first-class further activity. To date we have work on e nvironmental issu es Time ( 1998) fou nd that portable or in-stream using a very solid , field-based Figure 8 Diurnal va riations for January and Februa ry 1998 instrumentation is no substitute project with excellent data, a for carefu l stream sampling and large backlog of past work and a analysis in a welJ-equipped laboratory. an d ultimately to co m e up with highly- skill ed team of researchers an d Part of the diffi culty in getting sati s- sampling and stratification protocols for field management personnel. In the factory measurement is the high quality reliable measurem en t and examinati on s n ex t co uple of yea rs, we hope to of the water we are dealing w ith. A of hydrologic change associated with produce a stream of fi rst-class scientific second difficulty has been that tu rbidity forestry operations. papers, book chapters, field days and Such proj ects give grea t opportu ni- field to urs that will serve both the m ain sensors in particular require a large expanse o f water to give an accurate ties for more intensive measurements of stakeh olders and society generally. The measure and it is difficult to provide processes and this makes th em very major limiting facto r in th is is the such co nditions in a small stream bed. suitable for use by post-graduates or necessary time to produce quali ty work. Thirdly, in-stream instrume n tation post-doctoral researche rs. W e have U ndoubtedly the major opportuni ty often requi res fi eld calibration and this many ideas on this bu t have not of a m ultiple- catch ment project is the is difficult to do (particularly since it advanced them as much as we would di rectly field-based nature of the expe ri nvariably starts to rain as you try to do like beca use of the time commitmen ts imentatio n and observation. The downside of this is tha t the results tend it). A major proj ect aim is to look at the in getting the proj ect work u nder way. Finally, field sites like this are also to be specific and raise qu esti on s of statistics fo r adequate water sampling
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ENVIRONMENT extrapo lation and scaling when applied to other catchments. A decade or so ago, many hydrologists considered that compu ter modelling would make suc h field-based experi mentation obsolete . However, in fact, the need for calibration of the models and the difficulties inherent in models has made the importance of catchmen t-based modelling greater than ever. In the coming two years much of our efforts w ill go into extrapolation in time and space using the Croppers Creek data as a base. Topographically-based models such as TOPOG developed by the C R C for Catchment Hydrology (Vertessy et al. , 1994) offer great scope for extrapolation, but also have a substantial learning and calibration overhead. Such a project does have threats. Firstly, its funding is on a three-year basis and continuatio n is based on performance, w ith much of the time input being a labour of love rather than paid for in any explicit sense. Perhaps this is the way it should be, but the res earche rs also tend to be heavily involved in ea rning a living by contract research, lecturing o r administra tion and hence completion of 'public good' research can im pose substantial loadings with no clear return on the individuals and organisations involved. Secondly, the continuing change in
the charter and stru cture of the orga nisatio ns involved causes problems. To the authors, at least, a major miracle has been that the personnel involved in the old proj ect have managed to come together with the positive assista nce of the various fores t industry o rganisations. However, the re is co n tinued change in the organisations involved, with each change involving a new focus or examination of old commitments and this does not necessa rily lead to stabili ty. T he pace o f o rganisational change does not appear to be slowing in the immediate future. Third is the age profile of the researchers involved. The project has benefited greatly fro m the experience and 'can do' of the various participants but, by definition, this cannot go on forever. Our experience has been that such projects form an excellent training ground fo r young, field-based researchers and it is imperative that we get funding fo r employment and ed ucation of such people. Our post-graduate training experience is that such people are taken up by industry very quickly indeed.
Conclusion Project FO3 of the C R C fo r Catchmen t Hydrology is a field-based, multiple catchme nt project using modern technology to determine the
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Acknowledgements In writing this paper the contribution of Jim Morris an d Mike M cCormick of C FTT, Hugh Stewart, Simon Penfold, Ray Borschmann and Wayne Smith o f VPC (now Hancock Victorian Plantations), Rob Vertessy, David Perry and R ussell Mein of the C R C for Catchment H ydrology and many staff of FWPRDC are gratefully appreciated.
References Bren L J (1997) Effects of Slope Vegetation Removal on the Diurnal Variations of a Small Moun tai n Stream . Wacer R esources Research 33(2), 321-331. Bren L J and Leitch CJ (1986) Rainfall and Water Yields of Three Small Forested Catchments in North-east Victoria and R elation to Flow of Local Rivers. Proceedings R oyal Society of Victoria, 98 (1), 19-29. Bren LJ and Papworth M (1991) Early Water Yield Effects of Conversio n of the Slopes of a Eucalypt Forest Catchment to Radiata P ine Plantation . W acer R esources Research 27 (9), 2421-2428. Hopmans P, D W Flin n and P W Farrell (1987) Nutrient Dynamics of Forested Catchments in South-eastern Australia and Changes in Water Quality and Nutrient Exports Following C learing. Farese Ecology and Management, 20, 209-231. Leitch C J and Flinn D W (1996) Hydrological Effects of Clearing Native Forest in North-east Victoria: The First Three Years. Auscralian Forest Research 16, 103-1 16. Vertessy R , O'Loughlin E, Beverley E and Butt T (l 994) Australian Experiences with the CS IRO TOP OG Model in Land and Water Resource Management. In: Proceedings of UNESCO International Symposium on Water Resources Planning in a Changing World, Karlsruhe, Germany, June 28-30, 1994, pp. lll, 135-144.
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effect of radiata pine plantation developme nt o n wate r resources. It is a continuation of an older project and has benefited greatly from the infrastructure of the older projects. C urrently measurement and analysis is proceeding satisfactorily. To bring the proj ect to fruition involves many challenges of extrapolation and measurement.
AUSTRA LIAN WATER AND WASTEWATER ASSOC IATION
Leon Bren is a Project Leader with the Forest Hydrology Program for the CRC for Catchment Hydrology, The University of Melbourne. Peter Hopmans is a Research Scientist for the CRC for Catchment Hydrology, Centre for Forest Tree Technology, Department of Natural Resources and Environme nt and David Flinn is Director, Centre for Forest Tree Technology, PO Box 137, Heidelberg VIC 3084 and the Department of N atural Resources and Environment.
REF RM PIPE DREAM OR NIGHTMARE? B McRae Introduction
services sec tor increased by 89.8%, the Over the past 25 years, the serv ices u tility indu stry component experienced secto r has grown from arou nd 65% to a 32.5% decrease. The largest rate o f 80% of th e overall Australian eco nomy. change for all industries between 1990 At the sa m e tim e , util ity indu stry and 1998 occurred in th e util ity indusemployme n t levels have d eclined try, a 33 .4% decline. The decline in sharply. The 'utility industry' compo- utili ty industry employment in m etronen t of the se rvices sector includes politan areas (45.3%) was double the non- me trop olitan decline (21. 6%) , electricity, gas and water services. Wh y between 1981 and 1996. has utility indu stry employme nt Wh at is behind these changes? The followed a trend o pposite to the upward grow th in the services sector is eco nomic pe rformance of its parent large ly mirro red in Asia and o th er sector? W hat does econom ic reform of OECD and G7 countries. W hile th e the i ndustry mean and are water services report co mpares the Australian differe nt from elec tric ity and gas economy with other countries on th e businesses? This articl e explo res sector level, unfortunately it does not wh eth er water reforms will mirro r do so at the indu stry level. It does, electricity and gas reforms, are m erely a howeve r, m en tio n broad so urces o f pipe dream , or may result in a night- pressure for structural change, which mare- either for those involved in the include both market- and governmentindustry or fo r their customers. related sources. M arket-related so u rces include Utility Industry Reform tec hnological change, behav ioural Insight inco utility industry reforms, changes, trade and global specialisa tion and the larger context within which and resource recovery and depleti on. th ey are occurring, is provided in two T echnological change is perhap s th e rece ntly rel eased reports by th e most obvious fac tor at work in the Productivity Comm ission: Aspects of water industry. It is harde r to see how Strnctural Change in Australia and th e water industry may have bee n influMicroeconomic R eform by Australian enced by the othe r facto rs. Pri vate Governments 1997-98. The C o m- sec to r pa rti cipatio n , introdu ced via mission was established in April 1998 , government reforms discussed below, is fo llowing the 1996 administrative perhaps an example of trade and global amalgamation of the Industry Com- specialisation. Although it is easy to mission, Bureau of Industry Economics see that tec hnological changes have and Economic Planning Advisory occ urred , have they led to large C ommission. The Productivity Com- employme nt declines in the wa ter mision's role is to report and advise th e indu stry? Commo nwealth Treasurer on all More likely to influence the water are gove rnme nt-related asp ec ts of microeco nomi c reform, indu stry including matters related to industry pressures for change. Two of th esetrade and investment liberalisa tion and and productivity. Aspects of Strncttlral Change . .. is taxation and labour marke t reformsfull of data on the ch anging stru cture o f are similarly hard to relate to changes in the Australian econ omy over th e last 25 the water industry, although taxation years. Of particular concern to AWW A appears indirectly through governm ent m embers, perhaps, is information on business enterpri se reform. More signifemployment levels. B etween 1971 and ica nt p erhap s are two p articul ar 1998 , while overall e mployment in the reforms- competition and o ther regu-
latory reforms and infrastru cture and ge neral government reform s. Th e push towards privatisation , corporatisa tion and increased produc ti vity has bee n expe ri enced across the wh ole utili ty industry, including th e water secto r. Most notable among the governmentrelated in itiatives 1s the N ati o nal Compe tition Policy (N C P) and the Coun cil of Austral ian Governme nts (COAG) refo rm agenda. The Productivity Com m ission report Microeconomic R eform by Australian Governments 1997-98 provides an insight into the nature ofhow th ese initiatives have influenced the water indust1y .
Water Reform Implementation The report notes that the ' microeconomic reform effort is mo st advanced in the utili ty industries,' whi ch in this report include rail tra nsport as well as gas, electricity and water. Uti li ties were also ide ntified as th e area where th e NCP implementations had been most aggressive. T he repo rt notes that 'increasing competition between water u sers and e nvironm ental concerns has motivated reform in th e wate r indu stry. ' The goal of the NCP was to introdu ce compe t1t10 n , parti cula rly in areas where governm e nt monopolies occurred - the u ti lities being a prime example. Across the states, government services have been shifted to business ente rprises, wh ich are expected to adopt co mpetitive neutrality principles. Budge t allocati o n s are expected to result in the delivery of specific community servi ce obligations.
Competitive Neutrality C ompetitive neutrali ty means that prices must fu lly refl ect cos ts. Independent oversight bodies for water prices have bee n established in most states and progress has been made on eli mi nating c ross- sub sidies . In the urban sec tor , these may occur between WATER SEPTEMBER/OCTOBER 1999
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BUSINESS commercial and residential customers, but on a state level the gap between bulk water users and other interests is perhaps most significant for wa ter, given that agriculture is such a major water user, accounting for some 80% of water consumption in Australia. It is noted in the report that New Sou th Wales introduced entitlement transfers between industrial and irrigation users, including limi ted transfers to South Australia and Victoria. An 18% reduction in water rates for 80% of Victorian properties is identified as one of the benefits resulting from pricing reforms there. In Western Australia, real water costs increased by 3.2% for the average metropolitan household, while those for a medium-sized commercial business decreased by 10% (1992-3 to 1997-8) .
Government Business Enterprise Reforms Government business e n terprise reforms include restructuring, competltlve tende ri ng, corpo ratisation/ commercialisation and 'contestability'-allowing business ente rprises to contest service provision in other jurisdictions. There are a number of specific reforms in respect to water. In New Sou th Wales, Hunter Water's electrical and mechanical maintenance work was put out to tender, and although won by an internal bid, is seen as having introduced market competition. In Queensland, State Water Projects was commercialised. While water infrastructure assets are likely to remain a state monopoly, engineering, maintenance and operation services have been separated to promote transp arency and allow contestability. In South Australia, eight Highland Irrigation D istrict schemes were transfe rred fro m government to selfownership and an off- peak access regime was introduced in the Barossa Valley, allowing fo r commercial agreements. Approximately $ 140 million in capital works were awarded to private sector interests in Vi ctoria , w ith Treasury and Finance estimating 20-30% life cycle cost savings from the BOOT schemes. The Western Australian Government accepted a proposal by Preston Valley irrigators to manage their own distributio n system and transferred irrigation system assets, including the Waroona D am and H arvey and Collie River Schemes to the South West Irrigation Asset Cooperative.
Government Reforms A number of water- specific reforms are also identified in the arena of
government se rvi ce provision and regulation reforms. In the ACT, consumption- based pricing was introduced and c rosssubsidies were removed, including those between different water users and tho se between electricity and water. T his resulted in a marginal increase in water rates. In New South Wales, the Murru mbidgee and Coleambally Irrigation Areas were corporatised. Moves were made in Tasmania to transfer responsibilities from state to local governments in the case of the Esk Water Authority and the North West Regional Water Authority. In Victoria, a memo randum of understa nding (MOU) requiring improved water quality and environmental outcomes was established between the government and all nonmetropoli tan autho riti es an d the number o f regional au thori ties was reduced from 18 to 15, with efficiency savings estimated at 17% over the three years since 1994-95.
Effect on Employment The two Productivity Commission reports illustrate decli ning utility industry employment levels and identify a number of specific reforms that have occurred in the water industry. What abou t water indu stry employme n t levels, have they decli ned? Aspects ofStrnctural Change ... does not provide disaggregated water industry figures. M ost observers wo uld probably expect the bulk of the decline to be in the gas and electricity industries, where privatisation has been more aggressively implemented. T he overall figures themselves should be conservatively viewed. Conversations with staff involved with the report reveal that transfer of work from private to public sector companies is not necessarily accurately reflected in the statistics, and actua l utili ty industry employme n t declines are probably smalle r than reported (around 25%) . An excellent source of data is The Australian Urban Water Industry: WSAA Facts '98, published by the Water Services Association of Australia (WSAA). However , reporting of workforce numbers in WSAA Facts was discontinued after the 1996 version because the lack of data on numbers for the contract service provider workforce made this measure a poor performance indicator. Instead, subsequent reports have emphasised capital expenditures. The water industry employment figures provided in WSAA Facts '96 do indicate steep declines. For the 17 authorities listed, full- time workforce equivalents dropped from 20,500 in 1991-92 to 10,580 in 1995-96. The
report notes t hat this almost 50% decline reflects efficiency gains from implementatio n of commercial approach es, inclu ding the use of contract service providers. While WSAA Facts '98 does not provide data on employment levels, it do es support the P rodu ctiv ity Commission's fi nding that NCP reforms are lowering costs. The report provides business p erformance data on Australia's 19 largest water utilities for the six- year period co mme ncing 1992-93 . Over that time, water and wastewater revenu e per property decreased by 16.7% for the combined utilities, w hile operating cost pe r prope rty decreased by 18.6% . In the absence of other facto rs, o ne would expect declining revenues to result in an increased operating cost, due to the typically large fixed cost component of providing wa ter and wastewa ter services. Data on the electricity, gas, water and sewerage industries is also available in two Australian Bureau of Statistics publications. These are published i n alternating years, o ne relying on Australian Bureau of Statistics (ABS) data exclusively (#8226.0) and the othe r including information from oth er sources, p rimarily WSAA Facts for water industry data (#8208.0). For 1995-96, ABS #8208.0 showed 18,500 employees spread over 427 management units. For 1996-97, ABS #8226.0 reports 16,577 employees for 468 ma nagement units. The ABS data excludes the Austra lian Capital T e rritory Elec tricity and Wate r Corpo rati on (ACTEW) and the Northern T erritory's Power and Water Autho rity, since they are considered to be electricity businesses at the management unit level.
Closing the Gap An important point emerges from the above discussion-there is a lot of information on the Australian water industry that we simply don't have. Employment and other pertinent industry information is lacking in both accuracy and scope. While WSAA Facts is an excellent source of information on water utility business performance, it only covers the 19 largest water authorities and does not provide basic industry statistics, such as employment figures. A study has been planned under th e Agricult ure and Resources Ministerial Council of Australia and New Zealand to extend WSAA Facts to those Australian water utilities with 10,000-50,000 connections, which would pick up another 45- 50 utilities. In a separate effort, the Productivity Commission is currently working on a benchmarking study that WATER SEPTEMBER/OCTOBER 1999
BUSINESS will look at economic efficiency across the entire Australian water industry, p roviding a higher- order analysis to complement WSAA's business unit foc u s. Although both the ABS and WSAA publications reflect downward employment trends, the data can't be compared because the two are measuring different numbers of autho riti es . Also, both publications fail to account for employment ou tside the government sector. Conversations with ABS staff indicate that the reported employment information is based partly on survey of a sample of about half of the management units and partly on extrapolation. A rough count made by the Australian Water and Wastewater Associati on (AWW A) of water authorities to tals some 300- 330. The difference between AWW A's count and ABS's is n ot entirely clear since the info rmation is unpublished. H oweve r, irrigation districts are probably responsible for most of the difference. An authoritative listing of Australian water au thorities is not available- but it certainly should be. One of the u n dertakings being considered by A WW A is to p ull togethe r some of the missing industryspecific statistical informatio n. In addition to an authoritative listing of water auth orities, the Associatio n believes it would be useful to have information below this level, such as the total number of treatment plants and basic design parameters. From AWWA's point of view, the water industry includes private sector concerns and government interests other than those carrying out water supply and wastewater and drainage management. An accurate measure of the industry as a whole should reflect these interests as well. We'd welcome the thoughts and assistance of members regarding the need for this type of information and how we might best collect and present it.
Concluslon While shifts in the electricity and gas industries may outweigh those that have occurred in the water industry, i t remains to be seen whether this trend will continue or whether water reforms will catch up . One of the critical issues that has perhaps resulted in relatively slower implementation in the water industry is the relatively local nature of infrastructure when compared to electricity and gas. Some would argue, however, that this is a mis-oriented viewpoint. Reform in the power industry has seen businesses split three ways: generation, transm1ss10n and retaili ng. Refo rm in the telecommunications 42
WATER SEPTEMBER/ OCTOBER 1999
industry has followed a similar pattern. Is the re really any reason w hy this model couldn't be replicated in the water industry? Imagine a water retail market, where businesses usi ng the same distrib u tion network, operated by a single au tho rity, compete for customers. While this may seem fa rfetc hed, i t is really not that diffe rent from the current metropolitan Melbourne model. Whether this is a possible fu ture reality or merely a pipe dream remains to be seen. The declining employment statistics reported above, while unclear, may to some be a nightmare in progress-particularly th ose with a career stake in the industry. Others may feel that the price of reforms is too high if it means th e loss of institu tional knowledge or a decline in public control of water. T hose w ho fea r a n ightmare scenario may be quick to cite the New Zealand p ower outage or even the dilemma whe n Sydn ey W ater, Australian Water Services and Australian Water Technology were left to sort out responsibility during the Sydney water crisis. While most of us would not want to be without electricity or gas, the thought of being cut off from our water supply is unthinkable. Can we risk tampering with the systems that safeguard this lifeline?
References Australian B ureau of Statistics (1998) Electricity, Gas, W ater and Sewerage Industries A ustralia: 1995-96 (#8208.0), Canberra. Australian Bureau of Statistics (1998) Electricity, Gas, Water and Sewerage Operations Australia: 1996-97 (#8226.0), Canberra. Productivity Commission (1998) Aspects of Structural Change in Australia, Research Report, Auslnfo, Canberra. Productivity Commission (1998) Microeconomic Reform by Australian Governments 1997-98, Annual Report Series, Auslnfo, Melbourne. * Water Services Association of Australia (1998) The Australian Water Industry: WSAA Faces '98, WSAA, Melbourne.
Author Brian McRae 1s AWWA's Technical Director. He has bee n involved in the reform of government utiliti es in both Australia and the United States and is working wi th i nterested parties to improve o ur understanding of the Australian water industry and its rela tionship to the global wate r industry . He can be contacted at email: email@example.com.
Productivity Commission reports can be accessed at http://www.pc.gov.au. WSAA Facts '98 is available from the AWW A Bookshop (firstname.lastname@example.org) and WSAA (www.wsaa. asn.au).
EXPERIENCES WITH SMALLER SCALE
BUILD OWN OPERATE PROJECTS T Lambert Abstract The character of the Australian water and wastewater industry is unde rgoing substantial change. This includes the more frequent delivery of projects and services by way of Design and Construct; Operate and Maintain; or Build Own Operate (BOO) contracts . Henry Walker Environmental Pty Ltd (HWE) has been involved in two 25yea r BOO proj ects : the Aldinga Wastewater Treatment Plant and R euse Scheme for SA Water and t he Castlemaine Wastewate r Treatment Plant and associated facilities for Coliban Water. There are significant opportunities in Australia for smaller scale BOO projects. It is HWE's experience that the development of this market will require the various participants to examine further refine me n t o f risk profiles, edu cation of the Australian investment communi ty w ith respect to the opportunities provided by projects of this type and reductions in transaction costs.
Key Words BOO , manageme nt, risk, wastewater, reu se, sludge
Introduction The character of the Australian water and wastewater industry is undergoing substantial change. T his includes the more frequent delivery of projects and services by way of D esign and Construct; O perate and Maintain; or Build Own Operate (BOO) contracts. Contractual arrangements of these types are founded in the fundamental belief that they facilitate the transferring of risks (in a comp etitive environment) to those parties wh o are best able to assess, manage and price these risks (Salkeld 1997; Robb & Elliott, 1998). The initial experience in Australia with BOO projects was with substantial upgrades of water an d wastewater infrastructure requiring large capital expenditures. Clients are now examining using the BOO delivery mechanism for smaller scale projects. Henry Walker Environme n tal P ty Ltd (HWE) has been involved in two of these projects: â&#x20AC;˘ Aldinga Wastewater Treatment Plant
and R euse Schem e for SA Water tial penalties being applied for n on â&#x20AC;˘ Castlemaine Wastewa ter T reatment pe rformance. While a substantial Plant and assoc iated facilities for propo rtion of the risks associated with Caliban Water. the projects have been transferred to The Aldinga project comp rises a H WE, some differences do exist pump station, rising main and activated between the risk profile for the two sludge wastewater treatment plant to projects . These differences are a conseservice a population of 7,000 people. quence of the cu rrent evolving nature of HWE owns the wastewater from its these contractual arrangeme n ts and arrival at the pump statio n and is have had an influence on the pricing responsible fo r obtaining and maintain- structure. ing t he EPA licence. This licence prohibits the disc harge of treated Aldlnga wastewater in to the su rface drainage The Aldinga township is located system. A long-term co ntract exists approximately 45 km south of Adelaide with an adjacent w inegrower for the in the sou th-western corner of the sale of the reclaimed water. Payment fo r renowned Sou thern Vales wine produ cthe wastewater treatment services is by ing region. The present population is way of a monthly standing charge plus a approximately 3,500 p eople al though variable treatment charge. only approximately 1,100 are currently The Castlemaine project consists of connected to sewerage. W hen permitfive separate components. The first is ted by budgetary conside rations SA the provision of an upgraded wastewa- Water is extending sewers to existing ter treatment plant at Castlemaine with residences within a li mited area, as a total organic load capacity of 31,000 determined by poor soakage conditio ns equivalent population. Secondly, pre- fo r disposal of septic tank effiuent. New treatment facilities are provided on the premises of two of 'There are significant Castlemaine's larger trade waste producers. The refurbishment o f a opportunities in Australia trunk sewer and two pump station s in the Castlemaine for smaller scale BOO township is the third component. projects.' T he historic township of Maldon w ill also b e sewered as the fourth component with a rising main connec- subdivisions are required to provide tio n to the Castlemaine wastewater sewerage. The expectation is that over treatment plant. T he final component the 25-year life of the contract the of the project is the provision of a sludge population will reach 7,000 people. handling plant at Coliban's existing In d eveloping the basic concept for Bendigo BNR wastewater treatment the project early consideration was plant. This plant has a capacity of 2,250 given to the end uses of the reclaimed dry solid tonnes per annum. Again, water. The abutting landu ses were HWE is responsible for obtaining and mainly the growing of vines, olives, or maintaining the EPA licence. Payment almonds using drip irrigation. These for the services is by way of a quarterly crops benefit from a certain level o f toll which can be adjusted for changes nutri ents in t he irriga tio n water. in population or, in the case of the Consequently, the decision was taken Bendigo plant, for changes in tonnages to produce effiuent of a quality that treated. complied with N HMRC Reclaimed HWE is fully responsible for the Water Guidelines Class C and as such delivery of these services, with substanwas suitable for drip irrigation of crops which are to be processed. The plant is This paper was judged the best paper in being constructed in two stages with the the water industry management stream first stage having a capaci ty to service up of the AWWA 18th Federal Convention to 3,500 people . The second stage, to be held in April 1999. constructed about ten years into the WATER SEPTEMBER/OCTOBER 1999
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BUSINESS project, w ill have the capacity to service up to 7,000 people. HWE's responsibilities begin at the raw wastewater pump station . The wastewater is then pumped by way of a 2.9 km rising main entering the plant via an inlet screen. From the inlet screen the wastewater passes through an anaerobic reactor, then by way of a submerged inlet into a continuous flow oxida tion ditch which is the main biological trea tment unit. Aeration occurs by way of two horizon tal shaft su rface aera tors. Mixed liquor from the oxidation ditch flows over an outlet weir into a clarifier. The clarifie r separates t he biological solids from the liquor to produce reclaimed water. Sludge from the clarifier is returned to the oxidation ditch so that influent wastewater is continually introduced to active sludge. To maintai n solids concentration within th e system at a relatively constant level some solids are wasted on a daily basis to sludge drying lagoons. The reclaimed water discharges to storage lagoons. Irrigation is generally only undertaken in the five mon ths from November to March with the lagoons allowing winter production to be stored for reuse. Stage 1 includes a 150 ML storage lagoon sufficient to store the reclaimed water produced by a population of 3,500 people. The influent wastewater has a salinity in the range of 800-1,000 mg/L. Evaporation from the storage ponds has the potential to concentrate the salinity by 20% . The salinity of the irrigatio n water is critical to the ongoing management of the vines and is regularly monitored. To reduce the effects of evaporation the Stage 1 storage lagoon has been constructed with a stepped floor to reduce surface area as the volume decreases. The design and co nstruction was completed in J uly 1997 in accordance with the program. and budget. In keeping with current practice th e plant and reuse system are designed for unattended operations. Daily checks are undertaken by operations staff. Dial-up facilities are available fo r operator callout and critical alarms are connected by telemetry to SA Water's control room. The project has been licensed by the EPA and SA Health Commission. The irrigation management plan and e nvironmental management plan provide for a comprehen sive measurement and monitoring program. Currently the project is operating in the expected manner. SA Water is to be commended for th e foresight it demonstrated in the conception and delivery of the project. After undertaking a number of studies SA Water invited selected tenders to
deliver the Aldinga project based on the principles of: • a design, co nstruct and operate contract • a 25-year term • capability of serving a population of 7,000 people and able to be constructed in stages • lease of a 32 ha plant site from SA Water • lease of 62 ha of land from SA Water for the reuse component of the project • SA Water to pay a standing charge and a variable treatment charge • contractor to own wastewater and to have the rights to sell reclaimed water • contractor to obtain and maintain th e EPA licence • no discharge of treated wastewater to the surface drainage system. Given the small-scale nature of the project, a simple commercial structure was adopted. HWE took the role of main contractor, funding the project with parent com pany support. The company took responsibility for all services, subcontra cti ng the design, construction overview and co mmissioning support to Kinhill an d the operations and maintenance to United Water International. In-house resources were used to manage both the design and construction of the plant and the
ongoing operation. As part of the contract, HWE was allocated the risk of securing customers for t he reclaimed water. This was a significant risk since failure to secure customers would have jeopardised the project as other disposal options were not readily available. Agreement has been reached with one local winegrower to purchase all the project's reclaimed water. The agreement with the winegrowe r provides fo r the progressive supply of water to a number of parcels of land next to the plant as flows into the Aldinga catchment increase. The winegrower also takes up leases fo r the reuse sites when sufficient reclaimed water is available to irrigate these sites. The documentation requirements were in excess of w hat could be considered reasonable for a proj ect of this scale. The capital cost of the first stage of t h e project was of the order o f $3.5 million. Documentation costs accou n ted for some 7% of that total.
Castlemalne Caliban Water is a Victorian nonmetropolitan urban water and wastewater business based in Bendigo. Constituted under th e Wc1teI· Act 1989 Caliban provides water and wastewater
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BUSINESS services to 130,000 retail urban and rural water customers within a 16,500 km 2 area of Central and Northern Victoria. In October 1997 Coliban, together with 13 other similar authorities, entered into a memorandum of understanding with the Victo rian Minister for Agriculture and Resources to undertake projects to deliver a variety of outcomes for water and wastewater services (Robb & E lliott, 1998). Included in these outcomes were: • sewage treatment plants to discharge effiu ent to standards consistent wi th State Environment Protection Policy by 31 December 2001 • provision of sewerage services to all townships having both a reticulated water supply and a population in excess of 500 people by 30 June 2001 unless exempted by the EPA. To assist Caliban to achieve this target HWE has entered into a contract to provide the following services: • an upgraded wastewater treatment plant for the township of Castlemaine • refurbishment of a trunk sewer and pump stations in the Castle maine township • backlog sewe rage for the h istoric township ofMaldon, with sewage being transferred in a ri sing main to the Castlemaine plant
a sludge handling plant at Caliban's existing Bendigo wastewater treatment plant. At Castlemaine Henry Walker has taken over the operation and maintenance of the existing wastewater treatment plant upon commencement of the contract. T emporary facilities were provided to facilitate operations of the plant during construction of a new plant. Work is now proceeding on the design and construction of the new wastewater treatment plant on the same site. The new Castlemaine wastewater treatment plant will have a total organic load capacity of 31,000 equivalent populati on. The plant will use an In termit tently Decanted Extended Aeration (IDEA) process, with enhanced biological p hosphorus removal by way of a process which app roximates the UCT system. To provide for more effective control of the process, HWE is providing pre-treatment facilities on the premises of two of Castlemaine's larger trade waste producers. The wasted activated sludge from the Castlemaine plant will be stabilised and pasteurised in autothermal thermophilic aerobic digeste rs (ATAD) before solar drying and disposal off- site. Both the wastewater treatment plant and sludge management
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facilities incorporate Henry Walker's patented AAT technologies. In the township of Castlemaine an existing trunk sewer and two pump stations are being refurbished. Backlog sewerage is being constructed to service approximately 800 allotm ents in the historic mining township of Maldon. The topography of Maldon is such that it cannot be serviced by a single gravity sewerage system. Sewerage from a se ries of subsystems is transferred by gravity and rising main to the main pump station. T he sewage is then transferred 15.3 km in a rising main to the Castlemaine wastewater treatment plant. At Coliban's existing Bendigo wastewater treatment p lan t H enry Walker has taken over the operations and maintenance of the existing sludge management system. Currently, waste activated sludge from the BNR plant is dewatered by passing through a belt filter press before disposal on-site. T he new Bendigo sludge system will have a capacity to treat and dispose of 2,250 dry solid tonnes per annum of sludge. As at Castlemaine, the sludge will be stabilised and pasteurised using the ATAD process before solar drying and disposal off- site. Construction commenced on- site in early 1999. Current progress indicates that the proj ect will be fully operational in late 1999. The Castlemaine operati ons will demonstrate the latest advances in the design of both plants and pump stations fo r unattended operations. While daily checks will be made by operational staff, provision is being made for a computerbased SCADA system to provide monito ring, reporting and co ntrol fu nctions to both resident staff and offsite senior personnel. This system, together with the online monitoring which is being installed, will allow plant performance to be monitored and controlled directly in real time. Given the large scale of the project w hen compared with Aldinga, it has been necessary to adopt a more complex commercial structure. A Henry Walker spo nsored ownership company has e ntered into a contract with Coliban based on the principles of: • a design, construct, operate and transfer contract • a 25-year term • lease of plant sites plus an instrument of delegation of necessary powers under the Water A ct 1989 • the contractor owns wastewater and by-products • the contractor to obtain and maintain EPA licences • a tolling structure co nsisting of escalated and unescalated components plus adjustments for variation in