Torrens Taskforce

Torrens Taskforce Summary of Findings

FINAL REPORT 3 May 2007

Acknowledgements

This is a report of the Torrens Taskforce to the Hon Gail Gago, Minister for Environment and Conservation. The report was produced with the assistance of the Torrens Taskforce Reference Group, the Adelaide and Mount Lofty Ranges Natural Resources Management Board staff and consultants from ARUP Pty Ltd.

Torrens Taskforce - Members

Professor Don Bursill, Chair, Torrens Taskforce Professor George Ganf, University of Adelaide Dr. David Cunliffe, Department of Health Dr. Michelle Bald, Department of Water, Land & Biodiversity Conservation Mr. Peter Koukourou, Central Group, Natural Resource Management Board Mr. Mike Burch, Australian Water Quality Centre Professor Hilary Winchester, University of South Australia Dr. Simon Bryars, South Australian Research & Development Institute Professor Howard Fallowfield, Flinders University Professor Simon Beecham, University of South Australia

Torrens Taskforce – Reference Group Lord Mayor Michael Harbison, City of Adelaide Mayor Harold Anderson, City of Charles Sturt Councillor John Kennedy, Campbelltown City Council Mayor Bill Cooksley, Adelaide Hills Council Mr. David Duncan, Environmental Protection Authority Dr. John Howard, South Australian Water Corporation Mr. Bob Inns, Department of Environment & Heritage Ms. Carmel Schmidt, Primary Industry Resources South Australia Mr. Ben Clark, South Australia Tourism Commission Mr. John Phillips, KESAB Mr. Robert Myers, Landcare & Rural Community Conservation Groups Dr. John Cugley, Friends of the Gulf St. Vincent Mr. Jim Douglas, Western Adelaide Coastal Residents Association Mr. Rob Skipper, Torrens Lake Users Mr. Wayne Cornish, South Australian Farmers Federation Ms. Jane Corin, Conservation Council Mr. Trevor Ranford, Apple & Pear Association Mr. Michael Leyland, City of Adelaide Mr. Craig Bildstien, The Advertiser Ms. Yvonne Sneddon, Adelaide and Mount Lofty Ranges NRM Board

Thanks are also extended to the various staff, consultants and Members who provided significant technical inputs.

Ms. Whendee Moore, Ms. Kate Milburn and Mr. Borvin Kracman of ARUP Pty Ltd Mr. Paul Manning, Eco Management Services Mr. David Duncan, EPA Mr. Ken Schalk, Tonkin Consulting Professor Simon Beecham, University of SA Professor Howard Fallowfield, Flinders University Mr. Mike Burch, SA Water Quality Centre Dr. Stephen Gale, University of Sydney Mr. Alan Ockenden, Mr. Keith Downard, Mr. Andrew Thomas and Mr. Peter Shultz of AMLR NRM Board

3 May 2007 copyright

Torrens Taskforce Summary of Findings

Contents

Page 1 Executive Summary 1 2 Background 6 2.1 Introduction 6 2.2 Formation of Taskforce and Reference Group 7 2.3 Terms of reference and the Taskforce 9 2.4 Conduct and activities of the Taskforce and Reference Group 9 3 Aspirational Goals / Objectives for the Torrens 11 3.1 State of the catchment and river health 11 3.2 Setting inspirational objectives 13 3.3 Iconic objective for the river 14 3.4 Environmental values 14 3.5 Specific water quality objectives 18 4 Review of Previous Work and Existing Strategies 21 4.1 TCWM Plan 2002 – 2007 / Initial NRM Plan 21 4.2 Torrens Lake algae bloom prevention strategy 24 4.3 Adelaide Coastal Waters Strategy – current 24 4.4 Contemporary research 25 5 Investigations Undertaken by Taskforce 26 5.1 Key strategies requiring investigation 26 5.2 Slowing, storing and treating urban runoff 26 5.3 WSUD – Retrofitting Water Sensitive Urban Design 27 5.4 Torrens Lake nutrient balance and treatment options 28 5.5 Audit on stormwater / non stormwater inflows 31 5.6 Gross pollutant traps and capture 32 5.7 Heavy metals in sediments 32 5.8 Environmental enhancement flow / water transfers 33 5.9 Weir at Frome Road 34 5.10 Exotic and native vegetation in the catchment 35 5.11 Highbury and other storage options 36 5.12 Roles and responsibilities 36 6 Recommendations 37 6.1 Adopting water quality objectives 37 6.2 Current management strategies to strengthen and/or accelerate 38 6.3 Environmental flows in urban rivers 40 6.4 WSUD and modifying urban stormwater flows 41 6.5 Increase attention to compliance 42

Torrens Taskforce Summary of Findings

6.6 Torrens Lake initiatives 43 6.7 Community engagement 44 6.8 Roles and responsibilities 7 Reference Documents 46

Torrens Taskforce Summary of Findings

Executive Summary

Preamble Media and community concern over the state of the River Torrens, specifically the Torrens Lake’s susceptibility to cyanobacterial blooms over the summer of 2005/ 2006 promoted the Government, through Minister Gago to establish a Taskforce to review the situation. With the assistance of the Adelaide and Mount Lofty Ranges Natural Resources Management Board a Torrens Taskforce was established and led by Professor Don Bursill, a local scientist and water quality management practitioner. The Taskforce had a very strong and credible scientific bias with members from all of the State’s universities and selected experts from key agencies. To help support the Taskforce’s review, a community based Reference Group was established. This was done to ensure the various reviews, technical investigations and proposed strategies were able to be embraced and supported by the community. The Reference Group comprised of representatives from local government, community groups, state government agencies, conservations organisations, industry and the media. A good balance of urban/rural interests and perspectives as well as a community/government representation was achieved.

The Taskforce commenced in September 2006 to address the following terms of reference;

• Consider aspirational objectives, goals and targets for the River Torrens catchment, including the Torrens Lake.

• Review the previous work including relevant contemporary academic publications and the current programs and projects that have been implemented on the River Torrens and catchment as well as actions on the Torrens Lake.

• Identify current and possible future issues (including cyanobacteria and the accumulation of gross pollutants) that need to be addressed with respect to the health of the urban River Torrens and Torrens Lake from an ecological, social and economic perspective.

• Assess and recommend viable management and river rehabilitation options that are required to improve the River Torrens and Torrens Lake Condition and in particular to manage urban river algal blooms, litter and debris and the ecological health of the system. • Provide a report to the Minister on recommended actions and responsibilities and findings by the end of March 2007.

Review of previous work The Taskforce reviewed the management programs of the Adelaide and Mount Lofty Ranges Natural Resources Management Board (and its antecedent Torrens Catchment Water Management Board) and the recent Torrens Lake Algal Bloom Management Plan Update 2005. Other recent investigations, scientific papers and reports were also collated and reviewed. Both the Taskforce and the Reference Group were impressed by the amount if work and effort invested to date. However there were some key areas that needed to be further addressed. Broadly these areas can be summarised as follows; • A greater focus on clearly articulating water quality objectives to meet the desired environmental values of the various parts of the catchment; • Acceleration of fundamental catchment management activities, particularly in the rural catchment such as fencing off watercourses to stock;

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Torrens Taskforce Summary of Findings

• More attention on compliance to ensure both urban and rural communities exercise their duty of care and desist from poor management practices that lead to these water quality problems.

The review also confirmed the huge challenge that urban stormwater represents in terms of poor water quality from highly developed catchments. Unlike the newer urban areas to the north and south of Adelaide the Torrens urban catchment has virtually no water sensitive urban design features such as wetlands and swales, very little is left of the natural watercourse and a huge organic and chemical pollution load comes from street trees, motor vehicles, roads and a host of diffuse urban sources quickly transmitted through very efficient stormwater systems. This combined with the fact that cyanobacterial blooms in the Torrens Lake can occur even with very low nutrient (phosphorous) and organic carbon loads make the solutions to these problems extensive and expensive commitments. The Taskforce undertook a number of studies to increase understanding of particular issues and potential management strategies. These studies included nutrient balances in the Torrens Lake, water treatment options for urban stormwater and especially for the Torrens Lake, investigations of gross pollutant traps, dry weather stormwater discharges and various innovative water sensitive urban design projects. The recommendations of the Taskforce, with the support of the Reference Group, fall into three groups, namely; 1. Actions to be accelerated from the current management programs – eg. Fencing off watercourses to stock, increasing emphasis and follow up on compliance with existing regulations and policy and expanding the gross pollutant trap (GPT) facilities to cover all significant stormwater discharges, including First Creek which discharges near the Botanic Gardens. 2. Set specific water quality objectives and review and upgrade monitoring to regularly measure progress in achieving these objectives. A detailed set of water quality objectives is provided and in addition an overall aspirational objective of achieving conditions suitable for bringing back the platypus to the Torrens is proposed. 3. In order to meet the necessary water quality targets set for the Torrens Lake (and thereby avoid cyanobacterial blooms) a series of strategies were proposed; a) The provision of an environmental flow during the high risk period (Oct – March), with flows in the downstream reaches recovered, where feasible, for irrigation and ASR reuse; b) Development of an innovative biological filter for the Torrens Lake – an experimental project that shows significant promise of achieving a clean and clear Lake. If successful in the Lake, these filters should be added in other parts of the urban Torrens to improve water quality along its length, and; c) Long term commitment to retrofit the Torrens urban catchment with water sensitive urban design (WSUD) features that will slow water flows and help to deal with stormwater quality / quantity problems at the source. A complete list of the strategies recommended by the Taskforce and Reference Group are detailed below. These strategies are listed as being either short term (1 to 3 years) , medium term (3 to 10 years) or long term ( 10 to 50 years). Also for the purposes of budgeting, indicative costs are provided for actions except for those that could reasonably be expected to be undertaken as part of existing programs and commitments of Government agencies. These actions are notated as N/A, as shown below.

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Torrens Taskforce Summary of Findings

Adopting Water Quality Objectives Adopt WQ objectives through the EPA policy and monitoring system Short term $2m Consider reintroduction of the platypus once adequate progress is made Short/ medium N/A on improvements to water quality and ecological status term Regular reporting on progress in achieving objectives annual N/A

Rural Watercourse Fencing and Stock Management Accelerate fencing of rural watercourses and provide incentives to Short / $8.8m complete priority areas by 2012 medium term Establish guidelines/ code for expected (duty of care) practices and Short term N/A enforce Provide support to landowners to manage acidic soils and improve Short/ medium $1m retention of nutrients and organic matter term

Complete Urban GPT Program Install an effective GPT in First Creek at Botanic Park/Gardens Short term $0.5m Install GPT’s to 95% of urban catchment Short/ medium $2.8m term Check urban drainage systems for resident nutrient loads between Short term $0.1m stormwater events

Community Education, Behavioural Change and Compliance Review urban and rural education and change programs to determine Short term N/A best way forward Increase compliance program to reflect importance in achieving good Short term $1m practices

Changes to River Murray and Farm Dam Operations Change River Murray transfers to River Torrens to eliminate rapid Short term N/A changes (especially cessation) in flow associated with discharge operations Promote low flow bypasses on farm dams in stressed areas of the Medium term N/A Torrens catchment (as part of the WAP)

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Torrens Taskforce Summary of Findings

Environmental flows in Urban Rivers Gain approval for the provision of an environmental flow for the urban Short term $5m section of the River Torrens Develop a business case for securing an allocation from local catchment Short term N/A &/or River Murray Consider modifications to the spillway of Kangaroo Creek Reservoir to Short term N/A increase storage capacity to original design level. Assess the impact of this action on flood risk and on jointly providing releases of water for environmental flows Negotiate an operational plan to provide water to downstream users near Medium term $5m - the outlet of the Torrens to the sea $40m

WSUD and Modifying Urban Stormwater Flows Ensure WSUD principles and practical implementation are delivered Short/ long N/A through changes to planning policies term Develop detailed concept plan for wetland/detention basin in Botanic Park Short term $3.5m and/ or Gardens Adopt a WSUD demonstration suburb in the urban catchment to Short/ medium $2.5m showcase the future term Implement strategic stormwater detention basins on First to Fourth Medium term $6m Creeks and in selected locations on the main stream Use planning policies to stop and reverse development on and over the On going N/A urban creeks

Increase Attention to Compliance Refocus on compliance needs and assign clear responsibilities between Short term N/A EPA/councils and NRM Board Define “Duty of care” requirements for the rural and urban Torrens Short term $0.5m catchment communities Revise stormwater infrastructure standards and practices for discharge to Short/ medium $3m River Torrens and undertake a remediation program term Provide a regular audit and pollution incident follow up program Short term N/A

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Torrens Taskforce Summary of Findings

Torrens Lake Initiatives Investigate and trial innovative biological filtration system(s) for the Short/medium $0.3m Torrens Lake and if successful; term Design and construct an appropriate biological filtration system for the Short/medium $4m Torrens Lake and other urban water sites, such as St Peters Billabong term and upstream in the Athelstone reach Re-arrange all pumping from the Torrens Lake from its downstream end Medium term $2m Support current Lake management strategies of destratification, pond Short term $0.5m weed establishment, and improve water quality monitoring Remove artificial bird feeding stations from the lake, discourage feeding Short/ medium $0.2m of birds and commence a carp removal/eradication program for the term lake/river

Community Support and Engagement Maintain a community based Torrens Reference Group linked to the Short term N/A Board’s Central Group to support and guide the implementation of the Taskforce’s recommendations

Roles and Responsibilities Undertake a thorough review of the roles and responsibilities of agencies Short term N/A involved in the River Torrens (especially urban area) and recommend an approach to increase responsibility clarity and leadership in managing the River

The above recommended strategies combining short, medium and longer term actions collectively total over $50m of investment. This is the level of commitment required to seriously address the current water quality problems of the River Torrens.

The Taskforce and Reference Group agreed that all of the actions were important and must be progressed with a serious level of commitment. For this reason there was reluctance to put specific priorities on the individual actions, but instead recommend the whole package to Government.

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Torrens Taskforce Summary of Findings

1 Background

1.1 Introduction

The River Torrens and its catchment of just over 500km2 is a vital natural resource for the State providing important ecological, social and economic services for the community. The rural catchment supports a host of productive agricultural, rural living and commercial uses as well as being a watershed for Adelaide’s public water supply. Important areas of remnant vegetation and habitats, supporting biodiversity assets of the Mount Lofty Ranges are also under intensive pressure from past and present development. The urbanised Adelaide foothills and plains are traversed by the highly modified First to Fifth Creeks which flow into the River Torrens through the Linear Park, the Torrens Lake and then out into Gulf St Vincent through the artificial channel, Breakout Creek. This system doubles as part of the City’s stormwater drainage system and along the River, much of the Adelaide Parklands and recreational open space assets are located. Water quality from runoff events in the rural and urban catchments is extremely variable., Urban stormwater quality is at times very poor with all manner of diffuse pollutants washed into the river by a very efficient suburban street stormwater system. Rural runoff is also heavily polluted by nutrient rich silt and sediments, microbiological contaminants and diffuse pollutants from agricultural, urban and rural living land uses. A catchment management approach has been taken to manage these various impacts through the strategies reflected in the Torrens Catchment Management Plans (Reference Documents 1, 2, 3 & 4). Over the last decade significant effort and financial resources have been put into the catchment to improve water quality and enhance and protect ecological functions. Evidence exists to demonstrate that these efforts have been successful in improving the function and environmental status of the catchment – but there is still much to be done.

The Torrens Lake, in the centre of Adelaide, is the focus of national and international attention during the many and varied community events that take place on its waters, banks and in surrounding parks. The Lake supports the culture of Adelaide and is a feature of the city in which we should all take pride. Since 1998 issues with cyanobacterial blooms over summer have overshadowed the progress made in the catchment, with media attention focusing on Lake closures and stormwater pollution. The Torrens Lake is high profile water body and a major Parkland asset which accumulates litter and debris, sediment and nutrients. During summer it is prone to cyanobacterial (blue- green algae) blooms. Closures of the Lake to boating and rowing activities which are required to mitigate public health risks associated with blooms of cyanobacterial and also high microbiological counts after summer storms , attract media attention and community concern. The situation becomes increasingly intolerable when the Torrens Lake and surrounding Parklands are used as a stage for high profile community events such as the recent World Police and Fire Games and the regular Festival of Arts celebrations. While the Lake’s litter and debris problem can be cleaned up relatively quickly after stormwater events, the cyanobacterial bloom and poor water quality episodes generally last much longer. Attempts to prevent and manage cyanobacteria to date have only been partially successful. On some previous occasions, just prior to major public events, the Lake has been flushed with water released from the Kangaroo Creek Reservoir. This has resulted in the discharge of polluted water onto Adelaide’s beaches, which has generated concern from downstream

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communities. These flushing flows from Kangaroo Creek reservoir are a very short-term, expensive and unsustainable solution, especially in the current drought conditions. The 12-week closure of the Lake in 2005 and the impending cyanobacteria bloom prior to the opening of the 2006 Festival of Arts led the government to reconsider the objectives and strategies for the Lake and the broader catchment system. The State Government decided to establish a Taskforce to review these problems and provide advice on appropriate solutions. The Torrens Taskforce was initiated in September 2006 by the Minister for Environment, the Honourable Gail Gago, with five key areas of focus: • Determining aspirational goals for the catchment. • Reviewing existing knowledge and works done to date. • Identifying the issues that need attention now and in the future. • Investigating solutions and strategies to manage the issues. • Conclusions and findings for the government to consider. While the public focus has often been centred on the Torrens Lake it is important to consider the whole catchment and river system since the health of the Lake is indicative of the health of the upstream urban catchment and management of the Lake impacts on the downstream riverine environment and the coastal waters. The objectives, strategies and recommendations in this report are based on the need for holistic management of the catchment, a need for general improvement in the ecological status and connectivity between the various river system elements to better support the propagation and development of the natural biota of the whole system.

1.2 Formation of Taskforce and Reference Group

The role of the Torrens Taskforce was to guide the review, input specialist knowledge, and ensure all potential strategies were explored and critically reviewed. The Taskforce was chaired by Professor Don Bursill with representation from the Universities of Adelaide, South Australia and Flinders, Department of Health, Department of Water, Land and Biodiversity Conservation, South Australian Research and Development Institute, Australian Water Quality Centre with support from the Adelaide and Mount Lofty Ranges Natural Resource Management Board and project consultants Arup. Members include: • Professor Don Bursill, Chair, Torrens Taskforce • Professor George Ganf, University of Adelaide (UA) • Dr. David Cunliffe, Department of Health (DoH) • Dr. Michelle Bald, Department of Water, Land & Biodiversity Conservation (DWLBC) • Mr. Peter Koukourou, Central Group, Natural Resource Management Board (NRMB) • Mr. Mike Burch, Australian Water Quality Centre (AWQC) • Professor Hilary Winchester, University of South Australia (USA) • Dr. Simon Bryars, South Australian Research & Development Institute (SARDI) • Professor Howard Fallowfield, Flinders University (FU) • Professor Simon Beecham, University of South Australia (USA)

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Torrens Taskforce Summary of Findings

The water quality issues facing the River Torrens and the Torrens Lake required a fresh, critical review from a strong technical perspective. It was considered that the best scientific expertise from internationally acknowledged local experts should be applied to ensure contemporary and innovative options were explored. Independent views were also encouraged.

The Taskforce was supported by a Community Reference Group which comprised representatives from 20 different organisations including state government agencies, local government, the media and various community groups. Using the scientific and technical input from the Taskforce the Community Reference Group helped ensure community values and agency perspectives were included in the deliberations and ultimately in the recommendations. The membership of the Community Reference Group is listed below; • Lord Mayor Michael Harbison, City of Adelaide • Mayor Harold Anderson, City of Charles Sturt • Councillor John Kennedy, Campbelltown City Council • Mayor Bill Cooksley, Adelaide Hills Council • Mr. David Duncan, Environmental Protection Authority (EPA) • Dr. John Howard, South Australian Water Corporation (SAWater) • Mr. Bob Inns, Department of Environment & Heritage • Ms. Carmel Schmidt, Primary Industry Resources South Australia (PIRSA) • Mr. Ben Clark, South Australia Tourism Commission (SATC) • Mr. John Phillips, KESAB • Mr. Robert Myers, Landcare & Rural Community Conservation Groups • Dr. John Cugley, Friends of the Gulf St. Vincent • Mr. Jim Douglas, Western Adelaide Coastal Residents Association • Mr. Rob Skipper, Torrens Lake Users • Mr. Wayne Cornish, South Australian Farmers Federation • Ms. Jane Corin, Conservation Council • Mr. Trevor Ranford, Apple & Pear Association • Mr. Michael Leyland, City of Adelaide • Mr. Craig Bildstien, The Advertiser • Ms. Yvonne Sneddon, AMLR NRMB

The Taskforce met 10 times and the Reference Group met on 5 occasions. Although not all members could attend every meeting attendance and the value of input was very good.

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Torrens Taskforce Summary of Findings

1.3 Terms of Reference and the Taskforce

The Terms of Reference for the Taskforce were developed in consultation with the Minister, the Adelaide and Mount Lofty Natural Resources Management Board (AMLR NRMB) and the Taskforce members. The five Terms of Reference were:

• Consider aspirational objectives, goals and targets for the River Torrens catchment, including the Torrens Lake.

• Review the previous work including relevant contemporary academic publications and the current programs and projects that have been implemented on the River Torrens and catchment as well as actions on the Torrens Lake.

• Identify current and possible future issues (including cyanobacteria and the accumulation of gross pollutants) that need to be addressed with respect to the health of the urban River Torrens and Torrens Lake from an ecological, social and economic perspective.

• Assess and recommend viable management and river rehabilitation options that are required to improve the River Torrens and Torrens Lake Condition and in particular to manage urban river algal blooms, litter and debris and the ecological health of the system. • Provide a report to the Minister on recommended actions and responsibilities and findings by the end of March 2007.

1.4 Conduct and Activities of the Taskforce and Reference Group

The Taskforce met first in September 2006 and began by compiling relevant information. The Taskforce was assisted throughout the development of this report by a Project Officer from Consultant Arup and Board staff. Detailed briefing sessions were held in October 2006 together with the Reference Group. The briefings included discussions with Minister Gago with particular emphasis on community views. A site visit of rural and urban catchment issues and programs was undertaken on 28 October 2006 and it covered the rural and urban catchments and River reaches. The Urban Rivers Symposium, initiated by the City of Adelaide was held in November 2006. The Taskforce and Reference Group actively engaged in the forum which attracted valuable contributions from a wide range of water experts, community members and groups as well as presentations by ‘industry solution’ providers. The Board assisted in arranging for Dr Klaus Lindner, the recently retired Head of The Rhine Water Association of Germany to participate in the forum and also visit and reflect on the River Torrens issues. This was a very successful and strategic contribution. Although the Rhine River system is much larger and more complex than the Torrens, it was important to hear how such a system was changed over a thirty year period from a highly polluted drainage system to a more sustainable working river with a much improved ecological status. The Taskforce together with the Reference Group subsequently assigned desired Environmental Values for the River and segments of the catchment. EPA representative, Mr. David Duncan greatly assisted in this process. The Taskforce recognised at its earliest meetings that it was vital to establish detailed quantitative objectives to reflect water quality and hydrological requirements that will need to be achieved if the broader community expectations are to be realised. These quantitative

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objectives are also very beneficial in assessing the efficacy of improvement strategies and will assist markedly in monitoring progress in future. Any future planning decisions could also be assessed against these objectives to gauge their likely positive or negative impacts on the River system. The process has involved a series of meetings and workshops with the Taskforce and at appropriate stages with the Reference Group culminating in this report. A range of short and longer term options were considered. The Taskforce and Reference Group acknowledge that there are no quick fixes and that the objectives are likely to only be fully met in the longer term. However, given the provision of adequate resources, it should be possible to make substantial progress in the short to medium term – key issues being the provision of enhanced base flows (particularly during the period October to March), the modification of the hydrological regime to substantially smooth out moderate rainfall events and the provision of facilities to enhance the biological treatment and removal of key pollutants. Increased support for existing NRM Board strategies such as riparian zone restoration, wetland construction and enhanced gross pollutant removal would also have significant short to medium term beneficial impacts.

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2 Aspirational Goals / Objectives for the Torrens

2.1 State of the catchment and river health

Hydrology – in brief The hydrology of the River Torrens is important in understanding the state of the catchment. The hydrology has been highly modified by native vegetation clearing for farming and urban development, increasing drainage and channelling of creeks on the plains and foothills and the construction of diversion weirs and storages for public water supply and private use on properties via thousands of farm dams. Some basic figures on surface water are provided as follows (Reference Document 2); Watershed average yield 47,700 ML/yr Public Water Supply average use from Watershed 35,700 ML/yr Average transfers from River Murray 9,000 ML/yr Volume of Farm Dams 9,400 ML/yr (approx 1200 dams) Discharge from Torrens Outlet 40,000 ML/yr (mostly urban derived stormwater) Volume of Kangaroo Creek, Millbrook and Hope Valley Reservoirs are 19,000 ML; 16,000 ML and 3500 ML respectively. Volume of Torrens Lake 500 ML

The urban catchment has a very high proportion of impermeable surfaces (roads, roof and pavement) and runoff is very flashy and intense (short duration - high peak flows). The efficient drainage system (to minimise flooding) helps create short term high flows which on the Adelaide plains are very difficult (virtually impossible) to store in any significant volume. In contrast the rural catchment, even in its cleared state, only produces significant runoff after the catchment has been saturated, usually well into winter. Flows are generally slower to peak due to the surface storages, however when rain events are long and local farm dams become full, flows persist for many days. Managing water quality outcomes requires a good understanding of the catchments’ hydrology.

Water quality and river health The Board (including the antecedent Torrens Catchment Water Management Board) has undertaken a comprehensive program of water quality monitoring over the past decade that has included ambient water quality monitoring and pollutant load monitoring. It has also undertaken a river health assessment program by monitoring macro invertebrates at sites throughout the catchment. Monitoring macro invertebrates offers a good insight into the health of waterways because the number, species and diversity of macroinvertebrates is influenced by water quality, flow regime, sediment and habitat conditions in the river. The assessment of river health based on macroinvertebrate data has been standardised under the Ausrivas scoring system.

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A summary of macroinvertebrate analyses for the sites in the River Torrens is provided in the following table. In the table “Reference” indicates that macroinvertebrate numbers and diversity are judged to be reasonably similar to what could be expected at undisturbed sites. “Below Reference” indicates that at that site a mild impact on water quality, or habitat or both has resulted in a loss of macroinvertebrate families.

Table 1 Summary of macroinvertebrate analysis Waterway AUSRIVAS General Habitat General Comments Macro- Quality invertebrate Health (Rural) Torrens Below Moderate Poor Exotic Ground Cover Predominant, at Glen Devon Reference Diversity Isolated Pools Common Rd (Rural) Torrens Below Low Diversity Good Isolated Pools Common, Agriculturally at Griggs Road Reference to Disturbed, Stock Access Indeterminate, Reference Water Quantity Limiting (Rural) Torrens Below High Diversity Moderate Stock Access, Bank Erosion, Exotic Weeds at Carnell- Reference to to Good in Channel (Gorse), Water Quantity Boundary Reference Limiting, High macrophyte diversity Road (Rural) Torrens Reference Variable Very Large Variation in Water Quality and at Poplar Grove Diversity Good Quantity due to input of River Murray water (Rural) Torrens Below Moderate Good to Some Exotic Vegetation in CP at Cudlee Creek Reference to Diversity Very Conservation Reference Good Park (Rural) Torrens Reference Variable Very Highly variable water quality and quantity at Prairie Road Diversity Good (Rural) Reference High Diversity Poor Agriculturally Disturbed, Bank Erosion, Kersbrook Ck at Bank Slumping, Variable Flow Bagshaw Road (Rural) Miller Ck Reference High Diversity Moderate Nutrient Enriched, Algal Blooms, at Checker Hill to Good Revegetated Road (Rural) Angas Ck Reference Moderate Good to Agriculturally Disturbed, Bank Erosion, at Muellers Road Diversity Very Nutrient Enrichment, Some Revegetation, Good Water Quality Limiting Factor (Rural) Kenton Below High Diversity Poor to Stock Access, Bank Erosion, Low metals Ck at Reference to Good values, Variable Flow Gumeracha Reference (Rural) Cudlee Reference Moderate Poor Potential Water Diversion Upstream Ck Diversity (Urban) Torrens Reference Good Poor to Channel Choked with Macrophytes, Some at Silkes Road Diversity Good Revegetation, Silt Affected, Stormwater Ford Influence (Urban) Torrens Reference Good Very Habitat Limited by Poor Streamside at Windsor Diversity Good Vegetation Zone, Revegetation of Right Gardens Bank Recommended, High Algal Cover Common (Urban) Torrens Below Low Diversity Poor Poor Riparian Zone, Prone to Flooding and at South Road Reference Industrial/ Stormwater Run-off (Urban) Torrens Below Good Poor Poor Riparian Zone, Some Sediment at Tapleys Hill Reference to Diversity Anoxia, Flooding Common, Low Road Reference Macrophyte Diversity due to Horse Agistment, High Stormwater Run-off (Rural) Sixth Ck Reference Very High Very Edge Diversity may be limited by Low at Corkscrew Diversity Good Macrophyte Cover Road, Castambul (Urban) First Ck Below Low Diversity Poor Exclusively Exotic Riparian Zone, High at Botanic Park Reference to Stormwater Input, Low Macrophyte Reference Diversity (Rural) First Ck Reference Excellent Very Total Diversity likely to be underestimated at Waterfall Gully Diversity Good as edge habitat was generally not sampled, Riffle community clearly different

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to other communities in the catchment (Urban) Fifth Ck N/A Good Poor to Variable Discharge, Channel often Dry, at Fae Court Diversity Good Poor Riparian Zone (Rural) Fifth Ck Below Good Poor to Variable Discharge, Channel often Dry, at Montacute Reference Diversity Good Almost Exclusively Exotic Riparian Zone, Road Low Macrophyte Cover

The results of the macroinvertebrate monitoring program demonstrate the impact of land use on the overall health of the river and some generalised comments can be made as follows:

ƒ First Creek above the waterfall is the least disturbed sub catchment of the River Torrens with much of the catchment contained within the Cleland Conservation Park. As a consequence water is very good quality and flows all year round. Habitat is also very good and consequently macroinvertebrate data demonstrates reference condition with excellent diversity.

ƒ Sixth Creek at Castambul is a relatively undisturbed catchment with large areas of natural vegetation but with some agriculture and horticulture in the upper portions of the catchment. Water quality is good and flows all year around. Although habitat is disturbed at the monitoring site, macroinvertebrate diversity is very good and the site is in “Reference” condition”.

ƒ The Rural catchment generally has been impacted by agricultural enterprises and sites suffer variously from factors including: o impacted water quality including nutrient enrichment and algal blooms: o modified flow regime including intermittent flows in the upper catchment with long periods of no flow and conversely unseasonably high flows through the mid catchment due to water transfers from the River Murray; o poor habitat due stock access, bank erosion and presence of weed species. Consequently diversity is variable and whilst some sites are still classified as “Reference” condition a number fall “Below Reference”.

ƒ The two Upper Urban River Torrens sites were classified as “Reference” condition but suffer from limited habitat and the effects of stormwater inflows.

ƒ The two Lower Urban River Torrens sites and the downstream end of First Creek in Botanic Park fall to “Below Reference” condition because of poor habitat, especially in areas agisted by horses, and due to the poor quality of urban stormwater.

2.2 Setting aspirational objectives

There have been several attempts to identify and list the objectives and goals for the Torrens Catchment the most recent being the 2002-2007 Torrens Catchment Water Management Plan (Reference Document 2). This Plan provides a comprehensive list of qualitative targets, outlines strategies to reach targets and identifies priority issues. It also sets out a table of adapted Environmental Values for the Torrens Catchment consistent with the EPA’s Environmental Protection (Water Quality) Policy. The success of the Plan is demonstrated in the notable improvements throughout the catchment (Reference Document 3) although insufficient resources have prevented realising the targets associated with the Torrens Lake and urban stormwater. The Taskforce has used a staged process to identify and review objectives and targets.

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2.3 Iconic objective for the river

It was considered that a central, iconic objective was needed for the catchment to link the catchment zones together and to provide the community with a goal that will help to focus attention on the key strategies and actions that need to be applied across all areas and components of the catchment. There is a clear desire to see the catchment waterways looking better and functioning in an ecologically balanced way which will require a variety of strategies to be put in place. One way to achieve an overall improvement is to aim for the reintroduction of a sensitive species back into the river system and use the successful reintegration of this species to the river as a compelling icon of improved river health by successful management of the catchment and river system. Several species were proposed as potential indicators for the success of the improved management of the river. These ranged from frogs, fish and crustaceans however it was agreed that the platypus should be selected as the icon for the river as it would maximise community support and would provide an appropriate challenge to the successful implementation of the recommended strategies. Historical records indicate that the platypus inhabited the river up to at least the end of the 19th century although sightings were rare. The platypus is known to require a riverine and riparian habitat that has an abundant supply of prey species that flourish in what is considered good water quality, and it requires protection from consolidated river banks that provide nesting burrows. Successfully reintroducing the platypus will require great improvements in water quality, increased environmental flow through the river, better management of seasonal flows, rehabilitation of habitat areas and food sources, control of predatory animals (foxes, cats and dogs) and great support from the community to maintain a healthy river system. Interestingly, the Taskforce found that Melbourne Water has adopted the same objective in seeking to reintroduce the platypus to the Yarra River for similar reasons. Their program has been producing encouraging results. To capture community support and ensure the iconic objective drives water quality improvement, sites in the urban part of the River as well as rural sections should be considered.

2.4 Environmental values

2.4.1 General The Environmental Value (EV) assessment is a subjective process that aims to set water quality objectives to protect the environmental values of water bodies and/or courses within the Torrens catchment. EVs are the qualities of a water body that are important for a healthy ecosystem, or for public or private benefit, welfare, safety or health and that require protection from the effects of pollution and waste discharges. Generally, the EV process takes approximately two years. For the purposes of the Torrens Task Force report to the Minister, this was condensed into a few months. As a result, some limitations have been identified, whilst still being recognised as a valuable tool. Once the EVs have been determined, management goals and water quality objectives can be set, and management strategies implemented. In consultation with the Reference Group, the River Torrens was divided into four zones: rural; urban streams; Torrens Lake and; coastal. For each of these regions, values, threats to these values and potential management strategies to remove and/or reduce these threats were identified. A comprehensive analysis is detailed within the ‘Torrens Task Force Report’ by the EPA (Reference Document 22), with key relevant findings for each zone summarised below in Table 2.

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2.4.2 Brief Outline of the River Torrens EVs Zones

Rural Zone The ‘Rural zone’ is defined as the area from the River Torrens’ source near Mount Pleasant to the Gorge Weir below Kangaroo Creek Reservoir. It is predominantly rural, comprising four local townships and the River Torrens which is fed by a number of watercourses in varying condition, including Sixth Creek and Cudlee Creek. The Kangaroo Creek Reservoir and Millbrook Reservoir contribute approximately 20% of the water supply to Adelaide, sourced within this catchment. Water from the River Murray is also delivered at various points downstream of Mount Pleasant and Birdwood. Rural Zone EVs, management goals, key pressures and water quality indicators are outlined below in Table 2.

Urban Streams Zone The ‘Urban Streams zone’ is the section of the River Torrens from the Gorge Weir to near the St Peters River Park. The area is predominantly urban residential, with some primary production within the Adelaide Hills and a number of quarrying, industrial and commercial practices. There is also a considerable presence of parks and reserves forming part of the Greater Mount Lofty Parklands, through which run Second Creek to Fifth Creek. The upper reaches of these watercourses tend to be of high conservation value, but are disturbed within the Adelaide plains due to modification over time. Thorndon Park (decommissioned) and Hope Valley Reservoirs can be found to the north-east of the catchment. Urban Streams Zone EVs, management goals, key pressures and water quality indicators are outlined below in Table 2.

Torrens Lake Zone The ‘Torrens Lake zone’ incorporates the Torrens River from St Peters River Park to the Torrens Weir. It is thought that this area was integral to the life and culture of the local Kaurna indigenous population. These communities were displaced with European settlement and, in 1881, the lake and landscaped banks were created and have since become an important feature and area patronised by Adelaide locals and tourists alike. Surrounding land use is dominated by commercial and residential practices, with considerable tracts of land being parks, gardens and recreation grounds. First Creek, which is largely disturbed, feeds into the Torrens Lake via the Adelaide Botanical Gardens. In recent years, algal blooms as a result enormous changes throughout the entire Torrens River catchment since European settlement have caused considerable concern. Torrens Lake Zone EVs, management goals, key pressures and water quality indicators are outlined below in Table 2.

Coastal Zone The ‘Coastal zone’ incorporates the area from the Torrens Weir to the artificial mouth at West Beach and the nearby coastal environment. Breakout Creek, an artificial outlet through sand dunes to the sea, was constructed in 1935 to divert the Torrens River from its natural termination in reed beds between Glenelg and Grange. Land use in this zone is predominantly residential, with large areas of parklands in the upper section and equine farms along some sections. In this zone, much of the Torrens and the coastal environment at its mouth are highly disturbed, essentially acting as a stormwater drain transporting nutrients and sediments into the Gulf of St. Vincent. Coastal Zone EVs, management goals, key pressures and water quality indicators are outlined below in Table 2.

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Table 2 Catchment Zone Environmental Values, Management Goals, Key Pressures and Water Quality Indicators

Environmental Catchment Management Goal Key Pressure Water Quality Indicator Value Zone (Threats to Environmental Value) Microbiological contamination; nutrients, Microbiological, nutrient and chemical contaminant Improvement/maintenance of pesticides and other potential chemical levels are within recommended National Health and Raw Drinking Rural surface water quality for raw pollutants; modified flows; algal blooms; Medical Research Council guidelines. Water Supplies drinking water supply. River Murray capacity, salinity. Water supply needs from Mount Lofty Range met.

Improvement/maintenance of Microbiological contamination; chemical Contaminant levels in fish/shellfish are within Food Coastal surface water appropriate for food pollution. recommended Australian and New Zealand Food Consumption consumption. Standard guidelines.

Maintain and/or increase native Physical/chemical stressors below levels detrimental freshwater fish, macro to aquatic ecology. Poor stream health; poor connectivity; invertebrate, macrophyte and Maintenance/improvement of native fish and macro nutrient/sediment loads & turbidity; bank birdlife diversity. invertebrate diversity. instability/erosion; altered environmental Rural Restore riparian habitat to near as flows; microbiological and chemical Urban Stream Improved riparian habitat value, connectivity and possible natural condition. pollution; gross pollutants; salinity; exotic Coastal environmental flows that can support modified flora/fauna; land management; habitat aquatic ecosystems. Improve connectivity and destruction/alteration; increasing Aquatic environmental flows throughout development/infill; land management. Improved water clarity for an enhanced photic zone to Ecosystems catchment, River Torrens and provide better conditions to support a healthy benthic coast. floras and fauna. Physical/chemical stressors below levels detrimental Create a healthier and more Sediment, gross pollutant and nutrient to aquatic ecology. natural habitat capable of loads entering the lake; increased levels of dissolved organic carbon and biological Improved native fish, macro invertebrate, macrophyte Torrens Lake supporting wildlife diversity. oxygen demand; exotic fauna/flora species; and bird life diversity levels. Improved environmental flows habitat alteration/destruction; altered Biological oxygen demand below levels detrimental to through the River Torrens. environmental flows; irrigation extractions. aquatic ecology.

Rural Maintenance of water quality Microbiological and pesticide Microbiological and pesticide constituents below Stock Watering Coastal suitable for stock watering. contamination. levels detrimental to stock health. Maintenance of water quality Microbiological levels do not compromise human Rural Microbiological contamination; salinity; Irrigation suitable for crop, turf and garden health via irrigated crop product consumption. Torrens Lake irrigation. modified flows; algal blooms. Salinity below levels detrimental to plant growth. Maintenance of water quality for non-potable domestic use Salinity; pH; hardness. Water quality suitable for non-potable domestic use. Farm Use Rural (pumping, irrigation, stock Decreased/no corrosion/fouling of pumping, irrigation, watering systems). and stock watering systems.

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Microbiological contamination; gross pollutants; bank instability/erosion; Water body microbiological and nutrient levels are Rural sediment, nutrient and chemical within recommended National Health and Medical Urban Stream loads/pollution; increasing Research Council guidelines, decreasing associated Coastal development/infill; altered environmental human health issues at swimming locations. flows; poor water clarity. Water body microbiological and nutrient levels are Maintenance of surface water within recommended National Health and Medical Primary quality suitable for primary contact. Research Council guidelines, decreasing associated Recreation Microbiological contamination; human health issues at swimming locations. cyanobacterial blooms; gross pollutants; Biological oxygen demand within levels indicating Torrens Lake increased sediment load; poor water clarity; acceptable water quality. increased levels of dissolved organic carbon. Ceased/minimised cyanobacteria blooms. Improved water clarity for safety and aesthetic requirements. Microbiological contamination; bank Rural instability/erosion; nutrient and sediment Water body microbiological and nutrient levels are Secondary Urban Stream Maintenance of surface water loads; algal blooms; increasing within recommended National Health and Medical Recreation Torrens Lake suitable for secondary recreation. development/infill; altered environmental Research Council guidelines, decreasing associated Coastal flows; increased levels of dissolved organic human health issues at recreation locations. carbon. Microbiological contamination; bank instability/erosion; altered environmental Rural flows; nutrient and sediment Phytoplankton scums, filamentous mats, sewage Urban Stream loads/pollution; riparian zone fungus, leeches (etc.) are minimal. Coastal destruction/alteration; increasing Improvement/maintenance of Riparian zones, water clarity and colour are Visual Amenity development/infill; exotic flora and fauna. water course/body visual amenity. maintained/improved. Poor water clarity; nutrient, sediment, gross pollutant load/pollution; algal blooms; exotic Improved water clarity to support enhanced photic Torrens Lake flora/fauna increase; altered environmental zone and healthy benthic community. flows entering lake; riparian zone destruction/alteration. Maintenance of water quality for Microbiological contamination; bank indigenous/non indigenous cultural Water quality levels protect indigenous/non- values, and as an educational instability/erosion; nutrient and sediment loads/pollution; algal blooms; increasing indigenous cultural values, encourage use as an Rural resource. development/infill; altered environmental educational resource and allow traditional and Cultural & Urban Stream Protect indigenous sacred sites. flows; exotic flora/fauna; riparian zone spiritual use. Spiritual Values Torrens Lake destruction/alteration; artificial construction Coastal Indigenous sacred sites and ecological communities Maintenance of traditional/spiritual of Torrens Lake, Breakout Creek and use of waterways, including the (modified) of cultural and spiritual significance are draining of The Reedbeds may impact protected and maintained. presence of valued ecological upon indigenous cultural/spiritual values. communities.

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2.5 Specific water quality objectives

With the benefit of the Environmental Values and the water quality indicators the Taskforce worked up the actual water quality targets. One difficulty with the existing program was that monitoring the progress and success of strategies being implemented was limited to broad water quality objectives and visual observations rather than a clear, or quantitative demonstration of the outcomes and impacts. The main water quality issues (key pressures) for the catchment were identified by the Taskforce and debated and agreed to by the Reference Group. For each of these key water quality issues a set of detailed water quality targets were determined and are displayed in Table 3. It should be noted that these targets are, in part, aspirational and should be reviewed as the impact of the strategies becomes evident. Table 3: Water Quality Targets Parameter Targets Upper Rural Catchment (as measured at Milbrook, Kangaroo Creek and Hope Valley Reservoirs at inlets [i], in the target reservoir [r] or at Gumeracha Weir [g].) Faecal Pathogens Crytosporidium [i] <10 per 100L viable crypo oocysts for 95% of the time and a maximum incident value of 100/10 L Enterococci [i] 95 percentile <200 orgs/100 mL Nutrients Concentration TKN [i] 95 percentile <1000ug/L, over 12 month period Ammonia as N [i] 95 percentile <25ug/L, over 12 month period Total N [r] 95 percentile <1000ug/L, over 12 month period of which < 100ug/L should be Nitrate as N Total P [r] 95 percentile <25ug/L, over 12 month period of which <5ug/L should be FRP Load Total N [g] Av annual load reduction 25% by 2015 Total P [g] Av annual load reduction 20% by 2015 Concentration DOC [i] 95 percentile <10,000 ug/L, over 12 month period Heavy Metals • Investigate natural background levels as a means of determining appropriate objectives for the catchment, by December 2007. • Continue to use the ANZECC guidelines for waters and sediments and determine site specific objectives when the investigation to define natural background levels is completed. Habitat Availability • Numerical and/or descriptive targets to be developed, integrating the work of all agencies by December 2007, which: - identifies priority assets and the timelines and resources required for their protection. - long-term targets for protection or enhancement of existing habitat or biodiversity values and rehabilitation.

Torrens Lake and Urban Streams Dissolved oxygen in Median percent saturation 50% or above at 0.5-1.0 m above Torrens Lake the sediments, with minimum at any time or at any location over 24 hrs to be 25%. Total N During summer (Nov - March) 95 percentile <1000ug/L of which <100ug/L should be Nitrate as N

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Total P During summer (Nov - March) 95 percentile <25ug/L of which <5ug/L should be FRP Cyanobacteria in <10 ug/L total microcystins Torrens Lake or <50,000 cells/mL toxic M.aeruginosa or biovolume equivalent of <4 mm3/L for the combined total of all cyanobacteria where a known toxin producer is dominant in the total biovolume. BOD in Torrens Lake • (Interim) 1-2 mg/L during the summer (Nov - March). • Lake loads should not exceed the capacity of the aerators 95%of the time (except during storm events). Water Clarity Secchi disc visible at 1.5 m, except for 3 days after rain events. Faecal micro- • 95 percentile <200 orgs/100mL. organisms • Lake closed for primary contact for 3 days after rain events (same as West Lakes) • Lake not closed for secondary contact.

Heavy Metals As for upper rural catchment - by Jan 2007. Lower Torrens and Outflow to Coastal Waters Nutrients TKN 95 percentile <1000ug/L, over 12 month period Ammonia as N 95 percentile <25ug/L, over 12 month period Total N 95 percentile <1000ug/L, over 12 months of which < 100ug/L should be Nitrate as N Total P 95 percentile <25ug/L, over 12 month period of which <5ug/L should be FRP Heavy Metals As Above Turbidity 95 percentile <10 NTU over 12 month period excluding during any storm events with a recurrence interval > 1 in 1 year.

Faecal micro- Enterococci, 95 percentile <200 orgs/100mL at the Torrens organisms outlet excluding 3 days after rainfall events.

The most challenging water quality objectives to be set were for the Torrens Lake. Meeting the Environmental Values set for the Lake requires a total phosphorous level over summer of < 25ug/L 95% of the time of which < 5ug/L should be FRP (dissolved phosphorous). This is indeed a challenging target but it is required if cyanobacterial blooms are to be avoided. The objective of 10 000 ug/L for dissolved organic carbon in the Rural Zone is set for water supply purposes. This value is high by international standards, which are generally between 2 000 and 5 000 ug/L. This higher objective recognises that local soil and native vegetation types result in higher transport of naturally derived organic carbon in to water systems. The objective will encourage better land management practices and attention to compliance with pollution prevention policies and regulations, but it will mean that water supply treatment costs will continue to be higher than would otherwise be incurred if DOC levels were significantly lower.

The main benefits of these water quality targets are to enable: • better selection of specific management options to achieve the objectives through meeting water quality targets;

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• quantitative assessment of the progress within the catchment over time which should be publicly reported annually; • a more open (to the community and government) assessment of the progress within the catchment and; • the responsible agencies to monitor progress and redress management options where required.

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3 Review of Previous work and existing strategies

3.1 TCWM Plan 2002 – 2007 / Initial NRM Plan

Most of the goals, strategies and actions of the Torrens Catchment Water Management Plan 2002-2007 (Reference Document 2) have been imbedded in the Adelaide and Mount Lofty NRM Board’s Initial Plan 2006 (Reference Document 5). For the purposes of summarising the previous and ongoing programs of the catchment (natural resources) management plan and how well the goals were addressed, especially with reference to water quality, the following format was adopted. Goal: To improve and maintain water quality in the catchment to a standard suitable for community use (including public water supply), for sustaining ecosystems and to reduce impacts on receiving waters. Interim environmental values were adopted however water quality objectives other than those for reservoir water quality were not progressed to the stage where broad community access and understanding could be assured. Importantly, public health issues associated with recreational water bodies affected by high-faecal coliforms contamination were assessed to be a low risk. Continued support to the Adelaide Coastal Water Studies helped that program to progress and it has almost been completed. Identifying priority diffuse pollution sources and the development of mitigation measures were identified and supported. In the urban area the road runoff and the efficiency of the stormwater system to rapidly transport very high loads of organic carbon, sediment, silt and motor vehicle wear products causes high impact on receiving waters. The relative impacts depend on the time, duration and intensity of the event. Summer storms after long dry periods produce very poor water quality with organic carbon, faecal coliforms and biological oxygen demands as high as wastewater on some occasions. The combination of high bio-mass associated with suburban exotic and native trees and other contamination of oil, motor vehicle brake and tyre dust and bird droppings create a load that is not possible to control at its source through community behavioural change strategies alone. Programs of constructing urban wetlands, installing gross pollutant traps and eliminating effluent discharges and non-stormwater discharges have been implemented. In the rural area poor land management practices lead to diffuse pollution largely from overgrazing and intensive horticulture. A significant land management program and incentives via landholder assistance funding for watercourse rehabilitation, fencing and native vegetation restoration has been implemented. The creation of rural riparian buffer zones along watercourses through a combination of fencing and revegetation is well advanced. To date approximately 33 % of watercourses (53km) that need to be fenced have been fenced. The fencing of watercourses to exclude stock and encourage native vegetation re- establishment is beginning to be an accepted rural land management practice. Farmers have issues with the loss of “productive land” and the need for alternative watering points but in the main a new duty of care ethic is emerging. Goal: To ensure sufficient water is maintained in creeks, rivers and aquifers to be available for equitable and economic use (both private and public) and maintain ecosystems. As part of the catchment management approach, the Western Mount Lofty Ranges have been prescribed and water allocation plans are under development. More recently this initiative has involved the River Torrens through to the outlet at Breakout Creek and the groundwater resources of the Adelaide Plains. Although the first water allocation plans are still under development, the requirement to consider all water users including allocations of water for the environment is expected in the next 2 – 3 years.

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Permitting policies have been put in place to encourage off-stream farm dams but this has not always been possible. Low flow bypasses for farm dams have also been encouraged however widespread adoption for existing dams remains a problem. The cost of bypass systems can be high and/ or problematic for landholders to manage. Goal: To protect and enhance water-dependant ecosystems through integrated natural resources management. This goal has involved strategies to protect and rehabilitate rural and urban watercourses and their dependent ecosystems. As part of this program the ecosystem associations have been mapped and assessed in terms of high, medium and low valued assets. Surveys of native fish, habitat and river health have been undertaken along with plans for rehabilitation, native fish passage and mitigating the impacts of the River Murray transfers down the river. An environmental flow trial for the rural and urban reaches of the River Torrens is underway. However current drought conditions have delayed progress of these trials. Goal: To foster an informed, committed and involved community, which takes responsibility for, and actively supports its role in catchment management. Over the last ten years there has been significant progress to educate and involve the community to become more aware and ultimately change their behaviour to improve water resource conditions. Key examples are the WaterCare program; a whole of community education media campaign. The industrial stormwater pollution prevention programs hosted through local councils have been successful in reducing poor practices and facilitating sound commercial and industrial site management practices. The Our Patch program in the urban catchment has helped provide community ownership of watercourses, similar to the Landcare program in the rural areas. School education programs and Waterwatch have increased the understanding and appreciation of the catchment management approach needed to protect aquatic ecosystems. Councils have been engaged in programs to audit their practices and undertake operational planning awareness programs to reduce stormwater pollution and meet the EPA stormwater code of practice to improve water quality. A new and innovative State and local Government stormwater management policy and agreement have been achieved with increased emphasis on multi-objective stormwater management. Goal: To co-ordinate floodplain management at the catchment side A PAR on stormwater management was developed for all councils in the Torrens catchment and has been progressively adopted by Councils. A First to Fifth Creeks floodplain mapping project was undertaken and is about to progress into the next phase of investigating flood mitigation options and development plan policies. Goal: To establish monitoring and evaluate systems that enables the Board to assess the effectiveness of its programs and the health or the catchment. A comprehensive program of water quality monitoring and river health has been implemented and is reported on each 5 years. The program involves continuous water quality and quality monitoring at key rural and urban sites and compliments the ambient and river health (macro invertebrate sampling) program. The next 5 yearly reports are in preparation and will be available next month. Monitoring has included community awareness surveys and auditing of practices in various sectors including local government and industrial sites. Goal: To deliver the Board’s program in an integrated manner in partnership with all other stakeholders, taking into account environmental, economic and social considerations. This goal has been promoted through the successive development and implementation of the catchment water management plans in 1996 and 2001. These initiatives helped support the ultimate formation of the Natural Resources Management Board which connects catchment water management with the other natural resources of land, vegetation,

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biodiversity, coast and seas. NRM initiatives are now in place and the next round of the NRM plan for the region is currently being developed.

Conclusions; Review of supported programs indicates that water quality objectives that are at greatest risk of not being met are due to; • High pathogen levels in rural runoff to water supply reservoirs. • High nutrient levels in rural and urban watercourses • Erosion and sediment transport in rural and urban reaches of the river and creek system • Algal blooms in Torrens Lake • Visual pollution (litter and debris) in urban watercourses • Nutrient and sediment levels transferred to the coastal zone

Existing catchment management plan actions that are considered a high priority and should continue to be supported are: (i) Fencing of all rural watercourses to exclude stock and improve management of pastures with particular emphasis on the impact of acidic soils; (ii) Land management skills to reduce impacts of over grazing and animal husbandry activities; (iii) Stabilisation of erosion heads and river bank erosion in the rural catchment; (iv) More effective and extensive litter and debris management in the urban watercourses; (v) Improved detection and removal of polluting non storm water discharges ; (vi) Greater focus on compliance in both rural and urban communities with water resources and pollution control policies and regulations; and (vii) Environmental flows including low flow bypass system for farm dams.

One area where the catchment management plans have neither been effective nor influential is the areas of planning policy for development control. Both the rural and urban catchments are under ever increasing pressure for development. Environmental and water quality protection objectives have not been successfully embedded in planning and development control policies or practices. Over a decade ago a major Mount Lofty Ranges review was conducted. It stimulated a lot of debate and some innovative recommendations including calls for a single development authority for the Mount Lofty Ranges but overall the findings of the review were not successfully progressed. In its work the Taskforce did not dwell on the planning system’s performance or its perceived inadequacies although there is clear evidence of this in both the rural and urban catchment.

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3.2 Torrens Lake algae bloom prevention strategy

The original Torrens Lake Algal Bloom Management Plan of 1999 resulted in a lake destratification system being established to, in the short term, reduce nutrient (phosphorus) release from the lake sediments. In the longer term the plan was that aquatic vegetation (e.g. curly pond weed) would be re-established to balance nutrients in the lake. The destratification system involved up to 14 mixers and aerators in the lake, which operated successfully in the summer to mix the lake and generally elevate oxygen levels. However, occasional cyanobacterial blooms persisted in some years. Extensive lake monitoring was undertaken by AWQC from 1999-2005 and these data were used to review the system’s performance. In 2005, ARUP Water completed the Torrens Lake Algal Management Plan update for the City of Adelaide (Reference Document 8) and reviewed the performance of the destratification system. A whole range of other possible strategies were also reviewed including; • Pumping and re-circulation options to improve mixing and flows • Bacterial nutrient removal – a variety of unproven products • Algicide application – barley straw through to copper sulphate • Chemical sediment management – includes phoslock, alum etc • Electromagnetic treatments • Natural and artificial removal – includes natural (pond weed) and modified systems • Sediment management • Mechanical – optimise and increase current mixing system • Algae removal – from flushing the lake to installing filtration systems • Modify environment – use of environmental flows The recommendation of the 2005 review was to proceed with a phoslock application in the short term and in the medium to long term, re-establish macrophytes (aquatic vegetation) in the lake, increase environmental flows and improve the water quality entering the lake.

3.3 Adelaide Coastal Waters Strategy – current

The Adelaide Coastal Waters Study (Reference Document 9) was a major investigation to determine the cause of the seagrass decline off the Adelaide Metropolitan coastline. The impact of the past, present and likely future treated wastewater and stormwater discharges were assessed. Of particular interest to the NRM Board were the estimated impact of River Torrens stormwater and river flows and the definition of water quality objectives to assist with catchment water management planning and decision-making. The formal study results are not finalised, but it is understood that stormwater nutrients, turbidity and sediments may have been a contributing factor to seagrass die-off. Stormwater is the major contributor (67%) to sediment load discharged into the coastal environment. The Torrens River discharges some 10% of the total annual suspended solid load estimated at about 6600 tonnes. In contrast, wastewater treatment plants discharge some 71% of the total nitrogen load, the nutrient which is believed to have been a major cause of large-scale losses. The management of sediment discharge from the Torrens River would have environmental benefit to both the ecology of the river and the coastal zone. Other stormwater quality parameters such as freshwater (reduced salinity), heavy metals and pesticides were discounted as a cause of large-scale seagrass losses.

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In regard to pathogens, (faecal coliforms as an indication), high levels and high colouration at or near stormwater and river discharge points after summer rainfall is a concern and precautionary advice and signage has been implemented. It is important to note that a sanitary review of the quality of stormwater (via faecal steroid sampling) has confirmed there are no significant sewage overflows during these events. It is likely that the Adelaide Coastal Waters Study will conclude that while sewage and stormwater discharges have severely degraded and removed much of the near shore seagrass meadows, the impacts have stabilised. Efforts will be required to reduce coastal discharges adjacent to Adelaide in order for natural recovery to occur and/or for artificial rehabilitation to succeed.

3.4 Contemporary Research

University of Adelaide Professor George Ganf and his research students have been active in studying the Torrens Lake, River Torrens and the associated biological and ecological processes (Reference Document 6). A variety of research papers have shown that urban stormwater with very high levels of organic carbon and nutrients contaminate the Torrens Lake during rainfall events. Important work has been done to demonstrate the potential of naturally vegetated urban creeks to reduce nutrient transport from the catchment area and in conjunction with other strategies such enhancements to the creek and river system would assist in the control of pollutant loads to the lake. Flinders University Professor Howard Fallowfield and his team have been involved in a variety of research and development areas relevant to the Taskforce’s interests. Public health risk assessment using faecal sterol techniques, biological filtration research and bank filtration research and catchment and coastal investigations most recently associated with the Adelaide Coastal Water Study have been very useful in understanding the system and various options for remediation of it. University of South Australia Professor Simon Beecham and the Sustainable Water Resources Engineering group have been active in promoting water sensitive urban design innovations which have enormous potential to resolve water quality and quantity issues as well as improving urban amenity. The more challenging aspect of WSUD is implementing these techniques retrospectively in an established/developed urban catchment. Australian Water Quality Centre Mr Mike Burch and his team from AWQC have been actively researching Cyanobacteria for some time and are recognised as international experts in assessment, control and management techniques. Mr Burch has been advising the City of Adelaide and the NRM Board in algal management strategies. Their current research supported by SA Water and other water utilities is focussing on fundamental and applied research to develop non- chemical control techniques including ultrasound to replace the use of copper sulphate.

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4 Investigations undertaken by Taskforce

4.1 Key strategies requiring investigation

Strategies to achieve the water quality targets for the Torrens Lake broadly cover the following options: • source pollution control by improved management practices • modifying stormwater inflows, quality and quantity • improving current management strategies and/or operational processes • planning policy initiatives • treatment options for Torrens Lake water/sediment • Provision of environmental flows Consideration of the strategies were supported by specialist investigations, which are referenced separately from this summary report (Section 7, Reference Documents) and include: • Nutrient Balance for the Torrens Lake • Water Transfers and increased base flows • Conventional Filtration Plant • Investigation to Store & Slow Water along Torrens River and creek system • Opportunities to incorporate WSUD into the Torrens River catchment area • Weir at Frome Road • Investigation into trash racks for the Torrens catchment • Exotic/Native vegetation issues • Audit of potential sewer and dry weather stormwater discharges into the Torrens Lake Weir, Hackney Road to Torrens Lake Weir and further upstream • UV treatment of Cyanobacteria • Bank Infiltration • Bio-filtration • Storage options in the urban catchment to provide environmental flows

4.2 Slowing, storing and treating Urban runoff

A study by Tonkin Consulting (Reference Document 14) was undertaken to assess the feasibility of slowing down urban runoff from the urban catchment by temporarily storing water from rainfall events in the 7-15mm range in available open spaces. Stormwater would then be released slowly back in to the creeks where natural physical and biological processes would provide improvements in sediment and nutrient loads to the River system. The strategy would involve one or two detention basins for each of the creeks with sections of the reaches being restored with vegetation. The preferred locations are upstream of Bartels Road and Rundle Road on Botanic Creek, Tusmore Park and Botanic Park on First Creek, St Peters Billabong on Second Creek, Gums Reserve and Drage Reserve on Third Creek and Dennis Morrisey Park on Fourth Creek. Some 46 storage options were considered but only 25 were considered feasible. The detention storages collectively represent over 200 ML and could slow flow rates down to Page 26

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between 50 and 250l/s making natural water quality improvements achievable. The most practical detention storages represent approximately 150ML of storage and would collectively cost in the region of $6m. Creek restoration with planting and extensive reworking of the banks would cost in the vicinity of $2m per km where the watercourse has not been piped or built over. The detention basins would impact on the current open space community use in some areas. The necessary creek rehabilitation would also require widening and careful rehabilitation to ensure flood capacity is not compromised. Water quality objectives could be achieved most of the time for the stormwater treated in the designated storages especially for moderate summer storms of 15mm or less. However contributions from other parts of the urban catchment that could not be fitted with detention storages would from time to time cause water quality problems. This detention basin option would have implications or loss in some recreational use of open spaces and property acquisition along some creek lines. The slowing, storage and treatment of urban stormwater is a long term option with some local community impacts. It is unlikely that this strategy alone could achieve substantial water quality improvements without substantial property acquisitions and high cost in some areas. However, opportunities for implementing improvements where the land is available and for slowing flow in the main stream where possible and appropriate (e.g. the improvements in the Lockleys area) should be pursued. With the proposed changes to the Planning System to incorporate WSUD (see 5.3 below) these strategies are likely to produce meaningful benefits in the long term. Certainly, it would be a retrograde step to continue to allow the existing creek and river banks to be encroached upon further in the future.

4.3 WSUD – Retrofitting Water Sensitive Urban Design

Interest in WSUD techniques is growing in South Australia. A WSUD planning policy framework currently under consideration by Planning SA. Although applying WSUD to existing urban development is challenging and any outcomes will only be realised in the long term, WSUD has great potential to achieve the stormwater quality objectives being considered for the Torrens Lake. The University of SA selected a demonstration urban sub – catchment of Fourth Creek in Hectorville and applied WSUD features that would achieve the required water quality for the Torrens Lake. Features to be considered include stormwater swales, local rain gardens, permeable pavements and bio-retention road / traffic features. Such a retrofit would need to occur over a long period given the costs of approximately $100,000/ha; that is in the order of $10M/km2. There is between 30 and 50 km2 of urban area that would need to be retrofitted. Water quality objectives are likely to be met but only after significant retrofit however there are other significant advantages in water savings and flood protection that need to be considered as well. WSUD initiatives are long term but requires broad uptake and should be implemented as significant developments or redevelopments occur. This requirement needs to be encompassed within changes to the Planning System. In addition, local councils need to be proactive so that footpath, kerb and road restoration components are progressively implemented when possible.

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4.4 Torrens Lake Nutrient Balance and Treatment options

Nutrient Balance As has been noted previously in this report the issue of cyanobacteria (blue green algae) blooms in the Torrens Lake is the issue that has presented the greatest challenge to managing the Lake over the last decade. Previous studies of the problem indicate that it is the high level of the nutrient phosphorus in the Lake water that permits the cyanobacteria to develop into the numbers that cause blooms. A study (Reference Document 11) was undertaken to try to assess the various sources of this phosphorus as a step towards understanding how it may be controlled. There are a number of possible sources of phosphorus including atmospheric deposition, artificial bird feeding and groundwater inflow but it is fairly clear that inflows of stormwater from the catchment upstream of the Lake are the principal source of phosphorus. Generally the amount of phosphorus in stormwater, particularly during moderate to high rainfall events, is sufficient to support a bloom of cyanobacteria given other conditions are suitable. The other conditions typically required include still water, low river flows (long detention times), high solar radiation and warm water, all conditions that prevail in the Lake during the summer months. The original source of the phosphorus in stormwater includes that contained in the high loads of organic material washed from the catchment. Once in the Lake, a number of things can happen, some phosphorus is carried downstream in outflow from the Lake or is pumped out for irrigating the Park Lands. The remaining phosphorus either remains in the water or settles out with particles that form sediments on the bed of the Lake. During the summer months water stays in the Lake for months allowing a number of complex biological and chemical processes to occur that result in phosphorus being recycled to and from the water column and the sediments. These processes can change the phosphorus from particulate and organic forms to the much more bio-available forms that provide the nutrient for cyanobacterial blooms to develop. Currently the cycling of phosphorus from the sediments, and by fish and other biological processes within the Lake, is not understood completely. At the time that the original Torrens Lake Action Plan was developed in 1999 it was believed that the critical source of phosphorus was that released during the summer from sediments that may have been deposited during preceding months or years. The strategy of de-stratifying and aerating the Lake to maintain well oxygenated water at the sediment interface was devised as a strategy to minimize the release of phosphorus during the summer when it was known that the Lake became stratified and anoxic at depth. Whilst the destratification system has brought a number of benefits to the Lake by improving the levels of oxygen in the water it now seems clear that to prevent cyanobacteria blooms a goal must be to reduce nutrients in the water column as well. The ideal solution is to ensure that stormwater from the catchment is low in nutrient and options to achieve this are discussed elsewhere in this report. Another alternative is to remove the phosphorus from the water once it has entered the Lake. This option and related strategies also discussed under treatment options below.

Treatment Options Bank infiltration Bank infiltration is a technique used in Europe and North America. Rather than take water direct from a river it is extracted from wells alongside the river so that it is pre-treated by infiltration through the banks of the river.

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The water is subsequently filtered and disinfected for potable water supplies. Infiltration through the banks of the river improves the quality of the water by filtering out suspended material, adsorbing metals and nutrients onto soil particles and by biological degradation processes within the soil. A study (Reference Document 23) was undertaken to assess the feasibility of this technique to treat water in the Torrens Lake by extracting it from wells or trenches adjacent the Lake and returning it to the Lake. The study was inconclusive in terms of the effectiveness of this technique because of a lack of data about the suitability of the soils both from the perspective of their hydraulic conductivity and their effectiveness in treating the water. The study recommended that a program of field trials would be needed to obtain the data necessary to fully evaluate this option. What is clear however is that the very fast growth rate of cyanobacteria blooms requires any treatment system to be able to process the whole volume of the Lake in a time period of days to weeks. A preliminary estimate of 20 to 40 ML/day has been given as a required flow rate for the system. Such a system would require a large number of wells, pumps, pipe work and other infrastructure adjacent to the Lake. It would also require ongoing pumping and maintenance costs and for these reasons it is considered that at this time this option should not be progressed further. Conventional water treatment plant A study (Reference Document 13) was undertaken to develop designs and costs to construct a water filtration plant that would treat the water in the Lake specifically to remove phosphorus to levels that will prevent cyanobacteria blooms. In essence this option requires a pump station sited near the City Weir, a treatment plant and a pipeline to return water to the upstream end of the Lake. Two treatment plant options were investigated, one a Dynasand D2 dual stage filtration plant and the other a micro-filtration plant. Both options involve chemical dosing and disposal of sludge to the sewer. Both treatment plant options will produce water of the required target quality but it is currently not certain at what rate water would need to be treated to maintain the Lake at the required water quality. This is largely dependent on the frequency that storm events bring poor quality water into the Lake and to avoid this issue but still provide a range of likely costs, two treatment rates were investigated and costed. To provide a 10 day turnover of the Lake, considered to be the ideal, a treatment plant capacity of 50ML/day was costed and for comparison purposes a 20ML/day plant (25 day Lake turnover) was costed. The construction and operating costs for these options are tabulated below: Table 4 Lake Treatment Plant Type Construction Annual turnover Rate cost operating cost time 10 days 50 ML/day Micro-filtration $25,500,000 $1,140,000 10 days 50 ML/day Dynasand $19,800,000 $833,000 25 days 20 ML/day Micro-filtration $16,300,000 $623,000 25 days 20 ML/day Dynasand $12,500,000 $468,000

It is considered that the cost and the likely aesthetic impact of the structures associated with these options precludes them from serious consideration at this time. Biological filtration The Taskforce was particularly interested in the option of biological filtration of the lake which has the potential to remove suspended solids and nutrients. This treatment technology is used in the aquaculture industry and in effect is the basis of the water treatment used in most aquariums. An investigation (Reference Document 25) on bio-

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filtration for the lake was undertaken by Flinders University. This work concentrated on vertical-flow bio-filtration units targeting organic carbon and ammonia reductions. While phosphorous levels are not directly targeted, oxygen availability though artificial DOC reduction and nitrification may indirectly reduce phosphorous. An extension to the above investigation involves a more substantial biofilter that could be back flushed or cleaned and one that would have a greater role in removing phosphorous and suspended solids from the lake. This type of biofilter has biofilms that need to be physically or mechanically cleaned and further trials and investigations are required. It is anticipated that this bio-filtration system will be substantially less expensive than conventional water treatment options such as those used for public water supplies. Further research and trialling on this option is strongly recommended.

UV radiation on cyanobacteria Ultraviolet (UV) radiation is already used in the treatment of water and wastewater to destroy pathogens including bacteria, protozoa and viruses. A trial (Reference Document 20) was undertaken to measure the effect of UV radiation treatment on blue green algae (cyanobacteria ) in the Torrens Lake. The trial demonstrated UV did have a significant effect on cyanobacteria. There were variations in impact depending on dose rate and the species of cyanobacteria present. This treatment option warrants further research in the future. However, if the other strategies and actions recommended in this report are effectively implemented, it is unlikely that measures such as UV treatment will be required in the longer term.

Other proposed treatment techniques A number of products have been suggested as solutions to the problem of cyanobacteria in the Torrens Lake. These include chemical or biological agents, absorbent materials, and devices that impart electromagnetic or other signals into the water. These products have been assessed as either offering poor prospects of success or are other wise unsuitable because of cost or potential environmental impact. They are discussed in more detail in Reference Document 24, Treatment Processes, and are summarised below. Table 5 Product Claimed technique for water Reason for not being quality improvement considered Solar bee Solar powered floating water Effectiveness no greater than mixer existing mixer systems Sediment modifying Prevents phosphorus release Generally appear not to be agents from sediments sufficiently well developed for ƒ Limnofix application on a large scale. ƒ Barraclear Phoslock is a preferred sediment ƒ Treated pumice modifying agent. and treated zeolite Algicides including Toxic to cyanobacteria Potential environmental impacts ƒ Copper due to toxicity to fish and other Sulphate biota ƒ Hydrogen peroxide ƒ Dimethyl Sulphoxide Alum Precipitates phosphorus from Introduces Aluminium into the water system Barley straw Hinders cyanobacteria growth Inconsistent results from trials and incompatible with aesthetic

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and recreational objectives. Biological additives Out-compete cyanobacteria for Unproven on this scale. Costs nutrients not known. Introduce bacteria into an open system Electromagnetic Reduces size of water particles Not considered to be a proven water treatment so that cyanobacteria can not management technology ƒ Hydrosmart attach Ultrasonic Rupture gas vesicles within the Not developed to the point of cyanobacteria commercial application Absorbent Absorbs organic material (and Feasibility and effectiveness not ƒ Oil spill nutrients) proven Information carriers Imparts properties of source Not considered to be a proven ƒ Penergetic water using an information management technology carrier

Environmental options In the long term the re-establishment of macrophytes (e.g. curly pond weed) is a positive option. Trials over the last few years have been encouraging but recruitment will take some time. The improvement in water clarity would increase the photic zone and provide enhanced conditions for the establishment of a healthier benthic community, including the macrophytes. The nutrient balance report (Reference Document 11) indicated that a reduction ( and ultimate elimination) of carp in the lake would help nutrient and turbidity levels. This will be difficult to achieve but is worth pursuing. In addition, the elimination of feed stations around the lake and a program to discourage the feeding of birds should gradually reduce the bird population. Current practices are likely to be supporting a higher bird population than would otherwise be the case if artificial feeding was discontinued. This action would help reduce nutrient inputs to the lake. Both these actions would not be sufficient to control algal blooms but would provide some assistance in achieving this goal. It is recommended that artificial bird feeding cease and that a carp removal program be introduced.

4.5 Audit on stormwater / non stormwater inflows

City Weir to Hackney Road (Reference Document 19)

Hackney Road to Silkes Road, Paradise During January 2007 stormwater outlets into the River Torrens between Hackney Road and Silkes Road at Paradise were inspected. The inspection was undertaken following at least 5 days without significant rainfall so as to assess whether there were any flows into the river caused by discharges other than rainfall. A number of dry weather discharges were observed, the majority of which were clear water. Algal growth in some pipes indicated that some of these dry weather flows are relatively permanent. The source of these flows was not traced through the drainage system but the source of some may be air-conditioner condensate. Irrigation overspray is not considered to be a likely source of water given the water restrictions in force at the time of the inspections. One discharge was a result of construction activity and one other discharge smelt characteristically like sewage but again the source of this water was not traced. Although not seen during the inspection it has been noted by other observers that burst water mains frequently contribute significant quantities of turbid water to the drainage system during the summer. It is recommended that further investigative work be undertaken in relation to identifying and sourcing non-stormwater flows into the river.

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4.6 Gross pollutant traps and capture

A large investment has been made during the last ten years in the installation of gross pollutant traps (GPTs). GPTs collect litter and debris and prevent it from entering the river. A significant proportion of what is collected is sediment and organic material. An assessment of the stormwater outlets into the river shows that there are about 220 outlets between the beach and the Gorge. Of these, 48 are equipped with a GPT. The catchment served by these 48 outlets represents about 62% of the total catchment of the Torrens downstream of the Gorge. GPTs have generally been installed on the larger outlets, including the creeks, and the remaining outlets represent increasingly smaller catchments. As a consequence the cost effectiveness of installing GPTs will progressively reduce as the smaller outlets are equipped with GPTs. One obvious exception to this is the outlet of First Creek which does not currently have a GPT prior to its entry into the Torrens Lake. Prior to the establishment of the Wine Centre, a GPT and small silt trap were located on First Creek. The facility had to be removed as part of the Wine Centre development and despite negotiations with the Botanic Gardens it has not yet been replaced in a mutually acceptable location. Costs have been estimated to equip all the outlets into the Torrens with GPTs. These figures are summarised below in Table 6 along with the current situation. Table 6 Number of GPTs Percentage of Incremental catchment cost Current situation 48 62% $1,800,000 12 24% $1,500,000 27 9% $1,300,000 39 4% $1,300,000 94 1% $2,000,000

To provide coverage of 95% of the catchment will require a further investment of $2.8 million, to provide coverage of nearly 100% will require $6.1 million. These figures are preliminary and do not include any allowance for ongoing management or maintenance. It should also be noted that it may be more cost effective in terms of debris removed if some of the existing GPTs are augmented to increase their performance, rather than installing new GPTs on the smaller catchments. This matter requires further consideration as does the option of diverting smaller outlets into larger outlets so that the total number of GPTs required can be kept to a minimum and efficiency of cleaning and maintenance maximised. It is recommended that the installation of GPTs and a rationalisation of the smaller outlets continue with the longer term objective of providing GPTs to all outlets into the River Torrens.

4.7 Heavy metals in sediments

Prior to the formation of the Task Force an independent study was undertaken that sampled and tested sediments from the River Torrens and First Creek (Reference Document 10). The results of the survey, which showed concentrations of cadmium, lead, zinc, copper and phosphorus above the national trigger value for sediment quality at some point along the course of the Torrens, were widely circulated in the local media and attracted considerable community attention. Lower levels of contamination are evident in the headwaters of First Creek, where moderately elevated levels of copper and zinc are probably related to the underlying geology.

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The worst contaminated sites are along the industrial stretch of the Torrens from the West End Brewery through to Underdale and are highly likely to be related to the historical location of noxious industries, including metal foundries and chemical works. For example, the trigger value for lead in sediments is 50 μg g-1 and the high value (beyond which ecological damage is deemed to have already occurred) is 220 μg g-1; measurements at the worst industrial site were 832 μg g-1 in the <2.00 mm fraction and 4769 μg g-1 in the mud and plant organic fractions. Similarly high levels of phosphorus in the sediments are concentrated in the vicinity of the former Adelaide Chemical and Fertilizer Company downstream of the weir. The company’s main product was phosphate fertilizer and the concentrations reach their highest value of 7300 μg g-1, over twice the concentration at any other site. Channel sediments may form significant repositories for noxious materials and concentrations of trace metals in river sediments may be between 104 and 105 times higher than those in the corresponding river waters. The river sediments tend to accumulate, and the modifications to the flow behaviour of the river mean that they are neither being moved downstream nor diluted by mixing with relatively uncontaminated deposits. Although contaminated sediments may exert a significant influence on water quality, there is no easy or short-term solution to the problem. Despite the high metal levels in the sediments there is no evidence of them becoming bio available in the River. Macro invertebrate sampling in the River has not produced any concerning results.

4.8 Environmental enhancement flow / water transfers

The natural flow through the river system has been modified by the extraction of water for agricultural use and by capture in reservoirs for domestic and industrial use on the plains. This impact occurs particularly during the summer months when, with the exception of extreme storm events, no flow passes over the Gorge Weir. It is important to acknowledge the significant contribution the use of this water makes to social and economic outcomes for South Australia but also recognise that the loss of these flows has impacted on the urban part of the River Torrens, albeit now a highly modified environment. To redress this issue it has been proposed that additional flows be returned to the urban River Torrens by releases from Kangaroo Creek reservoir or alternate sources, such as capturing stormwater currently lost to the sea during rainfall events. Recognising that any rural catchment water released would need to be replaced by additional water pumped from the River Murray, a river that currently has its own problems in relation to record low flows and drought, a study (Reference Document 12) was undertaken to assess whether these flows could be captured further downstream to replace either existing mains water or groundwater use on the plains. Note that there would be environmental benefit of securing a River Murray allocation (licence) from upstream in NSW (for example) and bringing that flow into South Australia at least down to Mannum. The study was undertaken to investigate the amount of irrigated land that could be supplied by water pumped out of the River Torrens and to compare this demand with the volume of water required to reduce the average detention in the Torrens Lake to a time that would reduce the risk of cyanobacteria blooms. Sufficient open space was identified along the river, around the City of Adelaide, and in the near coastal areas of Henley Beach, Grange and West Beach to use a volume of water sufficient to maintain a detention time in the Lake varying from 15 days during the peak irrigation months of December and January transitioning to 45 days detention times during November and March. This represents almost 5 GL per annum.

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The total irrigation demand from all the areas identified equated to 4,700ML/annum. The cost of construction of the infrastructure to deliver this volume of water was estimated to be $40 million. It should be noted that a smaller scale project that selectively targeted users close to the river, whilst reducing the total demand for water, could be a significantly cheaper option at around $11m. This study provided a broad overview of the possible supply and demand for water but a number of practical issues would need to be solved before a scheme could be implemented. These include: • Identifying an owner and operator of the infrastructure. • Agreeing pricing structures for the delivered water bearing in mind that existing groundwater users currently pay no charge for the water. • Assessing what level of guarantee could be provided to potential users. • Location of storage required to balance demand against an effectively constant river flow. • Resolving potentially conflicting schemes such as the proposed Glenelg to Parklands scheme taking treated effluent to be irrigated in the City parklands. Notwithstanding these challenges the downstream harvesting of river flow should remain as a long term objective in the interest of conserving for beneficial use any environmental flow in the river. While the provision of urban environmental flows is likely to be mainly from the River Murray, a review of the yield possible from modifying Kangaroo Creek reservoir’s flood mitigation function would be worthwhile. In the early 1980’s approximately a quarter of this dam’s capacity was provided for flood control purposes (approximately 6.5GL). The resulting River Torrens Flood Mitigation Scheme provided a 200 year flood protection standard. A review of the potential to recover some of the reservoir space (yield) is warranted. Such a review could result in a compromise between lowering the flood control performance of the River Torrens Flood Mitigation Scheme and provision of an allocation of local catchment water for urban environmental flows. The Taskforce currently acknowledges that the current work on the Water Allocation Plans for the Western Mount Lofty Ranges (including the urban River Torrens) is fundamental to effecting changes to water allocations and implementing any environmental flow proposals. It will therefore be important for the Board (who is responsible for the WAP’s) to include future provision for the environmental enhancement flows for the urban River Torrens.

4.9 Weir at Frome Road

A study (Reference Document 16) was undertaken to investigate the construction of a weir just upstream of the Albert Bridge (Frome Road). A weir in this location would allow the upstream section to be converted back to a riverine environment rather than its current status as a shallow Lake. Currently there are a number of water quality issues with this section of the Lake that would be improved by the creation of a riparian section of River with pools and riffles. In conjunction with such a scheme a number of steep eroded banks could be restored and generally the amenity and ecological health of this reach of the river could be improved. The weir would also effectively reduce the volume of the Lake with a consequent reduction to the detention time in the Lake although given the volume of water currently in this section of the Lake this would be marginal. The water quality and other benefits of this proposal require further analysis.

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4.10 Exotic and native vegetation in the catchment

The urban catchment of the River Torrens is characterised by the very efficient street drainage system that conveys leaf and other organic debris from trees directly to watercourses. This contrasts with a natural catchment where leaf and other debris is generally not mobilised by rainfall runoff but remains on the ground, ultimately breaking down to become part of the soil matrix. Combined with this efficient drainage system is the fact that the urban catchment has considerably more biomass in the form of trees and shrubs than it would have had pre European development. Adelaide now has in excess of 20 million trees in the metropolitan area. Some 90% of these trees are in gardens and on private land. The situation is further complicated by the number of non native deciduous trees and shrubs now in the urban landscape which have higher nutrient content, faster breakdown rates and a short leaf fall season compared with the original native vegetation. The number and diversity of plant species has increased dramatically since 1836 with the number of tree species increasing by approximately 160% to include 38 native species and 60 introduced species. All of the above factors have lead to a considerable increase in the loads of nutrients and organic carbon entering the River Torrens and its tributaries. To help assess the contribution that trees may be making to the overall load of nutrients entering the River Torrens an assessment of the number of trees was made (Reference Document 18). Councils have good records about the numbers of street trees and this data was used. In the Torrens catchment there are about 100,000 street trees of which 47% are deciduous and 53% are evergreen. The estimate of the contribution that these street trees make to the load of phosphorus entering the River is summarised below. Note that this table is only for street trees and does not include trees in private gardens and open spaces which are likely to be at least 10 times the number of street trees. However these are generally not directly connected to the drainage system as are the street trees. Note also that the estimates do not include bark and branches dropped by native trees.

Table 7 Season Evergreen trees Deciduous trees Total Leaf mass (t) P mass (kg) Leaf mass (t) P mass (kg) P mass(kg) Summer 1,940 990 470 610 1,600 Winter 1,520 780 2,660 3,460 4,240 Annual 3,460 1,770 3,130 4,070 5,840

It is clear from the table that the deciduous trees produce the greatest amount of phosphorus although this occurs during the winter when flows in the rivers and creeks is greatest and consequently concentrations may be lower during the winter than the summer. The argument against deciduous trees based on leaf litter is flawed as all species create leaf litter and unlike deciduous species evergreen trees extract relatively little nutrients from their leaves before shedding. These leaves also fall most often during summer when water levels in creeks and watercourses are low and nutrient levels will be most concentrated. More research is required to understand fully the impact of leaf fall at different times of the year, how this may affect the concentration of nutrients in the water column and how these nutrients may be broken down, stored and processed through the river system but it would seem clear that notwithstanding other benefits of native vegetation, water quality will not be improved solely by removing exotic vegetation from the catchments.

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4.11 Highbury and other storage options

Lack of flow in the urban reaches of the River has been identified as an issue particularly in relation the Torrens Lake which, because of the very low flows, has very long residence times during the summer months. A number of options to capture winter rainfall and store this in the catchment for release during the summer were investigated (Reference Document 21). This stored water could be used as an environmental flow during the summer or, if necessary, as a flushing flow to replace the volume of water in the Torrens Lake. The options investigated, the corresponding volume of stored water, construction costs and comments are summarised in the following table. Table 8 Option Volume Cost Comments stored (ML) Thorndon Park 600ML $12M Requires property acquisition, rehabilitation and lining Reservoir of decommissioned reservoir. Water sourced from Fifth Creek and local catchments. Highbury 500ML+ $6M+ Previous sand and quartzite quarry owned by Ready- Quarry mix. Storage could be increased but at greater cost. Water sourced by pumping from River Torrens or from River Murray by transfer from Mannum-Adelaide pipeline. Dam on Sixth 1000ML $5M Water sourced from natural runoff from the catchment. Creek Hope Valley 600ML $2M Additional storage in SA Water’s reservoir achieved by Reservoir adding height to dam wall. An alternative of segmenting Hope Valley into two storages, one for water supply and one for environmental flows needs to be assessed as it could provide some 2 Gl storage. Storage in the 50ML Volume able to be stored in available open space River channel provides little benefit.

4.12 Roles and Responsibilities

During its deliberations the Taskforce noted that the lack of clarity of overall responsibility for the River Torrens made it difficult to progress improvement plans. However the Taskforce has not been able to explore in any detail the roles and responsibilities that the relevant authorities should have in the management of the River Torrens and its contributing catchment. The Adelaide and Mount Lofty Ranges NRM Board has responsibilities as defined in the NRM Act 2004. These are broad and allow the Board to develop and implement management plans, place orders on land owners to improve watercourse, land or vegetation management. There was a view expressed from the Reference Group that the Adelaide and Mount Lofty Ranges NRM Board should be the body responsible for the state of the health of the Torrens. Local councils are responsible for stormwater drainage into the river and have also agreed to maintain the River Torrens Linear Park, except that part of the channel which is the responsibility of SA Water. City of Adelaide have care control and ownership of the River Torrens and Torrens Lake between Hackney Road and Port Road. Better coordination of Council programs and activities on the Linear Park is needed. The EPA is responsible for water quality and environmental protection under the EPA Act. This has resulted in the establishment of a Watershed Protection Office and programs focussed on watershed and water quality protection.

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SA Water by virtue of the Metropolitan Drainage Act has responsibilities for the River Torrens downstream of Port Road. In the rural part of the catchment it has substantial reservoir, pipeline, aqueduct and water supply infrastructure and land assets and management responsibilities. Overall the current responsibilities for the River Torrens are shared across a number of state and local government bodies. The concept of a lead authority has some merit but ultimately all of the machinery of state and local government in regard to planning, policy, operations and maintenance will be needed. Further consideration and resolution of a lead authority is required but due to the complexity involved, this was not able to be provided through the Taskforce.

5 Recommendations The Taskforce considered a range of possible options and the preferred strategies and actions are set out below. It is important to note that several strategies require further investigation and in some cases further research before they can be adopted. Also some options can only be implemented over the long term as part of improvements to planning and development control policies. The recommendations presented here and below are an integrated suite that all require commitment. Recommendations taken up in isolation will not achieve the Taskforce’s water quality outcomes. The cost of actions in the strategies below is indicative only and is provided for comparative purposes. Where costs are expected to be covered by the normal operations of the various authorities or as part of ongoing development or policy, cost is designated as N/A.

5.1 Adopting water quality objectives

• It is essential to adopt clear sound water quality objectives to be able to set targets, assess progress and share information through the broader community. • An iconic target such as re-establishing the platypus in the Torrens (or an endangered native fish species) should be adopted and promoted in a way to raise and mobilise community commitment. Adopting the platypus as an icon target presents a number of natural resources management challenges that have multiple benefits and would support a number of the other objectives established by this study. Target re-establishment should include both rural and urban sites. • There should be a regular annual publicly available report on the progress in achieving the water quality objectives set out in this report.

Table 9 Strategy – Adopting Water Quality Objectives Actions Timing Cost Adopt WQ objectives through the EPA policy and Short term $2m monitoring system Consider reintroduction of the platypus once Short term N/A adequate progress is made on improvements to water quality and ecological status Regular reporting on progress in achieving Short term N/A objectives

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5.2 Current management strategies to strengthen and/or accelerate

• Overall the current management strategies (Torrens Catchment Management Plan actions as reflected in the Initial NRM Plan) are supported. However, there are some actions that need to be strengthened and accelerated. Others need to be reviewed and redirected. • Environmental guidelines prepared and implemented by industry need to be continued. This is how “duty of care” can be promoted and demonstrated as illustrated by the recent Environmental Guidelines for Viticulture and Perennial Horticulture. Accelerate Rural Watercourse Fencing and Stock Management Initiatives; • Rural programs that fence-off watercourses and exclude stock need to be accelerated and actively promoted as an expected land management “duty of care” practice. A target of fencing all watershed watercourses where grazing occurs by 2012 should be adopted and actively supported/funded. • In addition improved stock management practices on properties also have great potential to reduce pathogens reaching the watercourses and ultimately public water supplies. Increased focus on better stock/land management practices needs to be taken. • There is evidence to suggest that voluntary involvement in this program will not capture all land holders in the sensitive areas and observations were made during this study of cattle and other stock standing in the Torrens water course in relatively close proximity to off takes to water supply reservoirs. This is a practice that is far from satisfactory and something that would be unlikely to be seen in such sensitive areas of a water supply catchment in any other Australian capital city in 2007. • One aspect of improving grazing systems is the ability to manage and improve acidic soils. Application of lime to correct the acidity can also improve calcium to sodium ratios in soils, with attendant improved retention of organic matter and nutrients in the soil. This has been clearly demonstrated in local research at the laboratory and small pilot scale. The economic feasibility requires checking on a larger scale trial, but if reduced costs to water supply treatment are included with agricultural and environmental benefits pilot it is likely that the cost/benefit will be attractive.

Table 10 Strategy – Rural Watercourse Fencing and Stock Management Actions Timing Cost Accelerate fencing of rural watercourses and Short / medium $8.8m provide incentives to complete by 2012 term Establish guidelines/ code for expected (duty of Medium term N/A care) practices and enforce Provide support to landowners to manage acidic Short/ medium $1m soils and improve retention of nutrients and organic term matter

Continue the Septic Tank Remediation Program in the Watershed;

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• Continue the remediation of septic tanks in rural areas that are poorly maintained, this will reduce the risk of effluent contamination of surface water runoff in the watershed.

Complete the Urban Catchment GPT Program; • All urban catchments stormwater systems should have effective gross pollutant traps and/or litter and debris management systems in place by 2012. Analysis has shown that it would be practical for 95% of urban catchments to be covered by GPT and local councils should accept responsibility for maintaining these. • High nutrient, organic carbon loads and the early appearance of “black water” after storms suggest some resident system loading may be occurring – this needs to be checked.

Table 11 Strategy – Complete Urban GPT Program Actions Timing Cost Install an effective GPT in First Creek at Botanic Park Short term $0.5m Install GPT’s to 95% of urban catchment Medium term $2.8m Check urban drainage systems for resident nutrient Short term $0.1m loads between stormwater events

Expand the Environmental Water Requirements to the urban River Torrens; • The current trials to provide for environmental flows in the Torrens as part of the prescription process are supported. This effort should be extended to the urban catchment. Amenity, urban riverine ecology and the health of the River Torrens and Torrens Lake require a serious allocation of environmental water. Refer to section 6.3 for more detail. Targeting Community Education and Behavioural Efforts; • Community education programs that promote general awareness do not necessarily lead to effective behavioural change. With the benefit of the last 5 to 10 years experience of community behaviour change programs, a review needs to be undertaken to assess their effectiveness. Importantly the highest priority behavioural change actions need to be clearly identified prior to further investment in this area. • Not enough has been done to deter poor practices resulting in poor water quality in the catchment – a stronger compliance approach is needed. This applies to both urban and rural catchments. There does not appear to be strong follow up and investigation of pollution incidents or compliance on poor land management practices.

Table 12 Strategy – Community Education, Behavioural Change and Compliance Actions Timing Cost Review urban and rural education and change Short term N/A programs to determine best way forward Increase compliance program to reflect importance in Short term $1m achieving good practices

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Changes to River Murray Transfers and farm dam operations; • Transfers of River Murray water by SA Water to reservoirs in the Torrens catchment have resulted in severe bank erosion along a significant length of the River. This erosion is due in part to the action of rapidly turning on the water discharge valves when water transfers are required and switching off the flow without ramping it down over several days. Dispersive sub soils on the banks of the river exacerbate the problem. The sudden reduction in flow causes the banks to slump and increases the chances of further erosion during subsequent rainfall events. Water transfers need to be managed so that the flows avoid any further deterioration of the affected banks. This matter was raised with SA Water during the course of this study and the issue is being investigated by SA Water in collaboration with the Board. SA Water has indicated that action is planned to provide better control of the water transfer rate. • The proliferation of farm dams in the rural catchment has impacted on local environmental flows and watershed resources. The use of low flow bypasses on all new farm dams should be required. Where possible low flow bypasses should be retrofitted on existing dams with large capacity and/or where they are intercepting more than 50% of the available run off in stressed sub catchments. • The current investigations and consultation for the Western Mount Lofty Ranges Water Allocation Plan(s) is likely to include the issue of farm dams and desirable low flow bypass policies. The strategies below should be considered and discussed in these WAP’s

Table 13 Strategy – Changes to River Murray and Farm Dam Operations Actions Timing Cost Change River Murray transfers to River Torrens by Short term N/A slower ramping down of discharge operations Promote low flow bypasses on farm dams in stressed Medium term N/A areas of the Torrens catchment (as part of the WAP)

5.3 Environmental Flows in Urban Rivers

• The provision of a base flow in the highly modified urban River Torrens in the summer months would improve the river’s water quality, connectivity and general amenity and recreational values. • Summer and spring flows from Sixth Creek have been diverted by Gorge Weir. An allocation in the order of 5 GL over the summer period (Oct – Mar) would generally improve the urban River’s health. This allocation may need to be reduced to 2GL in low rainfall years, with an attendant increase in the risk of water quality issues arising in the Torrens Lake. • Securing 5 GL of water for the urban Torrens could be achieved through purchase of up state irrigation water, local allocation from SA Water and/or increasing yield from Kangaroo Creek Reservoir by raising the spillway/ lowering the available flood storage for the River Torrens Flood Mitigation Scheme (circa 1980’s). • Opportunities exist for such an environmental base flow to be subsequently extracted from the River Torrens (just before its discharge to sea) for irrigation use in open

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Torrens Taskforce Summary of Findings

space, golf courses or even as an ASR sustainable groundwater management strategy. • This environmental flow for the urban River Torrens is a key issue for consideration in the Western Mount Lofty Ranges Water Allocation Plan(s) (WAP’S). The strategies below should be discussed and considered in these WAP’s.

Table 14 Strategy – Environmental flows in Urban Rivers Actions Timing Cost Gain government approval for the provision of an Short term $5m * environmental flow for the urban section of the River Torrens Develop a business case for securing an allocation Short term N/A from local catchment &/or River Murray Consider modifications to the spillway of Kangaroo Short term N/A Creek Reservoir to increase storage capacity to original design level. Assess the impact of this action on flood risk and on jointly providing releases of water for environmental flows Negotiate an operational plan to provide water to Medium term $5m - $40m downstream users

• [Note: Purchase of River Murray water license at $1m per GL: pumping cost is approximately $0.1m per GL].

5.4 WSUD and Modifying Urban Stormwater Flows

• The use of the River system as an urban stormwater drain and flood mitigation system results in the rapid transfer of water along the creeks and main stream during rainfall events. This relatively high velocity of water flow to the sea causes a range of adverse effects to the river and coastal system, including severely limiting the opportunity for natural filtering and decomposition possesses to occur in the catchment, the creeks and the main stem. Measures to slow the flow down, without markedly impacting on flood risk are a key part of improving the ecological status of the River and need to be pursued. The existing restoration work undertaken in the Lockleys section of the River is an excellent example of what can be achieved – and the water quality improvements there are visually obvious. Other types of flow intervention will be more appropriate in other circumstances further upstream. The construction of small weirs and associated riffle zones in the main stem at appropriate locations will be required to enable in stream water quality improvements, habitat enhancement and to enhance the benefit of periodic environmental flows. • The Taskforce and the Reference Group would strongly support the government in the development of a strong WSUD planning policy framework. The Taskforce considers that planning policy needs to be changed to require implementation of water sensitive urban design (WSUD) in all new developments and significant redevelopments. Furthermore, the actions recommended in this report will be negated to some degree if the current planning system approach continues to allow further encroachment of housing on land immediately adjacent to the creek and river system.

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Torrens Taskforce Summary of Findings

• Detention and/or a wetland and swale system for Botanic Park will help improve stormwater quality from First Creek.

• Opportunities to slow, store and release stormwater in other strategic and in stream locations need to be further reviewed such as on: Botanic Creek upstream at Rundle and Bartels Roads; First Creek at Tusmore Park; Second Creek by major modifications at St Peter’s Billabong; Third creek at the Gums Reserve and Drage reserve; Fourth Creek at Denis Morrissey Park and near Torrens Linear Park • In addition, urban watercourses should, as far as practical, be rehabilitated with native aquatic vegetation and where possible bank layback. This strategy represents a very long term action that eventually, over a long period, will improve water quality and the environmental values of the urban creeks.

Table 15 Strategy – WSUD and Modifying Urban Stormwater Flows Actions Timing Cost Ensure WSUD principles and practical implementation Long term N/A are delivered through planning policies. Develop detailed concept plan for wetland/detention Short term $3.5m basin in Botanic Park and/ or Gardens. Adopt a WSUD demonstration suburb in the urban Short/ medium $2.5m* catchment to showcase the future. term Implement strategic stormwater detention basins on Medium term $6m First to Fourth Creeks Use planning policies to stop and reverse Long term N/A development on and over the urban creeks * Based upon an allowance of $100,000/ha

5.5 Increase Attention to Compliance

• Increase emphasis on compliance to achieve water quality objectives – at this stage there has been little in the way of compliance expectations put on the urban and rural communities. • In the urban catchments while codes of practice on storm water management exist there is currently little enforcement or investigative effort by the EPA and councils. • In regard to expectations from rural landowners there is little information which makes clear their duty of care to the environment. • A checklist of best practice and legal requirements is needed for rural landowners. Industry guidelines as developed through industry/Government partnerships for viticulture and perennial horticulture is a good example. • Raise the engineering standard of stormwater discharge structures to minimise erosion. Currently there are many stormwater structures discharging high energy flows in to the river system with little regard being paid to the erosion damage caused to the immediate stream environment. Apart from the aesthetic damage to the system, this represents a significant load of nutrient and other contaminants that are moved in to the aquatic system – with the potential to cause subsequent water

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contamination in the River or at the coast. The upgrading and further expansion of gross pollutant traps on these storm water discharge points should provide an opportunity to raise the standard of the engineering practice for these structures. • Regular audits of industrial and business premises, especially in the EPA un-licensed sites are needed.

Table 16 Strategy – Increase Attention to Compliance Actions Timing Cost Refocus on compliance needs and assign clear Short term N/A responsibilities between EPA/councils and NRM Board Define “Duty of care” requirements to the rural and Short term $0.5m urban Torrens catchment communities Revise stormwater infrastructure standards and Medium term $3m practices for discharge to River Torrens and undertake a remediation program Provide an audit and pollution incident follow up Short term N/A service

5.6 Torrens Lake Initiatives

• Continue to refine the operation and effectiveness of the de-stratification mixing system on the Lake. • Further design, develop and trial a biological filtration system for the Torrens Lake. Such a system would have similar applications on problem water bodies such as St Peter’s Billabong and for enhancing water quality improvement in the areas along the main stream where deeper water exists now – or where deeper water will be created by additional efforts to restrain moderate rainfall events. This biological treatment process could be seen as an additional set of lungs being provided to help the natural purification mechanisms destroyed or severely impacted by the channelling of the creek system. • Rearrange all pumping from the Lake to be just downstream at the City Weir; This measure will increase the turnover of the Lake water by one cycle each year. The suggested 5 GL of environmental flow allocation to the Torrens system would result in a reduction in the detention time in the Torrens Lake to approximately 2 weeks in the higher risk period through late spring, summer and early autumn. This would severely limit the opportunity for cyanobacterial growth in the Lake as these organisms are relatively slow growing. • Control to support sensible environmental actions such as re-establishing aquatic vegetation, remove carp and cease artificial bird feeding on the lake. Table 17 Strategy – Torrens Lake Initiatives Actions Timing Cost Investigate and trial innovative biological filtration Short/medium $0.3m system(s) for the Torrens Lake and if successful; term

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Design and construct an appropriate biological Short/medium $4m filtration system for the Torrens Lake and other urban term water sites, such as St Peters Billabong and upstream in the Athelstone reach Re arrange all pumping from the Torrens Lake to be Medium term $2m at the downstream end Support current Lake management strategies of Short term $0.5m destratification, pond weed establishment, and improve water quality monitoring Remove artificial bird feeding stations from the lake, Short/ medium $0.2m discourage feeding of birds and commence a carp term removal/eradication program for the lake/river

5.7 Community Engagement and Support

• The strategies outlined above will require genuine community engagement and support in their adoption and implementation. This includes engagement during the process of developing options, setting policy and formulating budgets. A collaborative approach is needed to ensure there is strong agreement on the package of measures proposed and in the implementation stages. It will therefore be important to continue the process commenced in the Torrens Taskforce and Reference Group, where discussion, input and community ownership is encouraged and ultimately government acceptance of the longer term measures can be secured. • Many of the strategies recommended will require fundamental changes and commitment to new approaches, particularly in the WSUD area. Also there needs to be acceptance of environmental flows for urban river system and commitment to planning initiatives that make provision for long term sustainable urban water management. • A process of maintaining community input and support for the strategies will be essential. The combination of representation and ownership through community leaders and influencers, academics, government representatives and program managers will be essential. This needs to be achieved with the collaboration of existing community based entities such as the NRM Board’s Central Group.

Table 18 Strategy – Community Support and Engagement Actions Timing Cost Maintain a Torrens Taskforce community based Short term N/A Reference Group linked to the Board’s Central Group to help support and guide the implementation of the Taskforce’s recommendations

5.8 Roles and Responsibilities

• There is a lack of clarity of the roles and responsibilities for the River Torrens, especially in the urban area. A concerted effort to remedy this problem, tidy up the legislation and provide clear overall leadership and coordination is required. .

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Table 19 Strategy – Roles and Responsibilities Actions Timing Cost Undertake a thorough review of the roles and Short term N/A responsibilities of agencies involved in the River Torrens (especially urban area) and recommend an approach to increase responsibility clarity and leadership in managing the River

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6 Reference Documents

1. Torrens Comprehensive Catchment Water Management Plan 1997 – 2001, Torrens Catchment Water Management Board 1997 2. Torrens Catchment Water Management Plan, 2002 – 2007, Torrens Catchment Water Management Board, 2002 3. A Catchment Journey to Integrated NRM 1995-2005, Torrens Catchment Water Management Board, 2005 4. Initial Plan, Adelaide and Mount Lofty Ranges Natural Resources Management Board 2006 5. River Torrens Reports – AMLR NRM Board Library Listings, Sept 2006 6. Publications; The Torrens Lake, River and feeder creeks by Limnology Laboratory, University of Adelaide – 2006 7. Briefing Session Presentations for the Torrens Taskforce and Reference Group, 19 October 2006, Torrens Taskforce. 8. Torrens Lake Algal Management Plan Update 2005 – Arup Water in association with Eco Management Services, Centre of Water Research for Adelaide City Council, 2005 9. Adelaide Coastal Waters Study, Draft Summary of Findings for EPA, CSIRO 2007 10. Gale, R.J.B., Gale, S.J. and Winchester, H.P.M. 2006 ‘Inorganic pollution of the sediments of the River Torrens, South Australia’, Environmental Geology, vol. 50, pp 62-75 11. Phosphorus Balance for Torrens Lake, Arup, Report prepared for Torrens Taskforce, 2007 12. Investigation: Water Transfers to Downstream Users, Arup, Report prepared for Torrens Taskforce, 2007 13. Water Treatment for Torrens Lake – Investigation Report, United Water, Report prepared for Torrens Taskforce, 2007 14. Investigation to Store and Slow Flows along the River Torrens, Tonkin Consulting, Report prepared for Torrens Taskforce, 2007 15. Opportunities to incorporate WSUD into the Torrens River catchment area, University of South Australia, Report prepared for Torrens Taskforce, 2007 16. Upstream weir on the Torrens Lake at Albert Bridge, Arup, Report prepared for Torrens Taskforce, 2007 17. River Torrens Stormwater Drainage Inlet GPT Opportunities, Adelaide and Mount Lofty Ranges Natural Resource Management Board Memo prepared for Torrens Taskforce, 2007 18. Exotic and Native Vegetation Impacts on the Torrens River Catchment Water Quality, Arup, Report prepared for Torrens Taskforce, 2007 19. Audit of Potential Sewer and Dry Weather Stormwater Discharges into the Torrens Lake, Hackney Road to Torrens Lake Weir - Adelaide City Council, Upstream of Hackney Road - Arup, Reports prepared for Torrens Taskforce, 2007 20. Effect of UV Radiation on the Viability of Cyanobacteria in the Torrens Lake, Australian Water Quality Centre, Report prepared for Torrens Taskforce, 2007 21. Storage Options, Arup, Report prepared for Torrens Taskforce 22. Torrens Taskforce Environmental Values - Draft in progress, EPA, prepared for Torrens Taskforce, 2007 23. Initial Assessment of Bank Infiltration at the Torrens Lake to Improve Water Quality, United Water, Report prepared for Torrens Taskforce, 2007 24. Treatment Processes, Arup, Report prepared for Torrens Taskforce, 2007 25. Torrens Lake Management Proposal: Bio-filtration Proposal, Flinders University, Report prepared for Torrens Taskforce, 2007

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