2010 Audit of the Sydney Drinking Water Catchment Volume 1 – Main report Report to the Minister for Water 2010 Audit of the Sydney Drinking Water Catchment Volume 1 – Main report Report to the Minister for Water © 2010 State of NSW and Department of Environment, Climate Change and Water NSW. The Department of Environment, Climate Change and Water and State of NSW are pleased to allow this material to be reproduced for educational or non-commercial purposes in whole or in part, provided the meaning is unchanged and its source, publisher and authorship are acknowledged. Specific permission is required for the reproduction of photographs and images. Published by: Department of Environment, Climate Change and Water NSW 59 Goulburn Street, Sydney PO Box A290 Sydney South 1232 Ph: (02) 9995 5000 (switchboard) Ph: 131 555 (environment information and publications requests) Ph: 1300 361 967 (national parks, climate change and energy efficiency information and publications requests) Fax: (02) 9995 5999 TTY: (02) 9211 4723 Email: [email protected] Website: www.environment.nsw.gov.au Report pollution and environmental incidents Environment Line: 131 555 (NSW only) or [email protected] See also www.environment.nsw.gov.au/pollution Cover photos: Russell Cox Top: Cordeaux River near Pheasants Nest Weir Bottom from left: 1. Fitzroy Falls 2. Gully erosion Wollondilly River sub-catchment 3. Tallowa Dam 4. Agriculture Upper Nepean River sub-catchment ISBN 978 1 74293 026 8 DECCW 2010/973 November 2010 Printed on recycled paper Contents Volume 1: Main report Summary Recommendations Chapter 1 Introduction ..................................................................................1 1.1 The Sydney Water Catchment Management Act 1998 .................................... 1 1.2 Overview of the audit....................................................................................... 1 1.3 The Sydney Drinking Water Catchment........................................................... 2 1.4 Approach to drinking water quality management ............................................. 2 Chapter 2 Audit Methodology.......................................................................4 2.1 Overview ......................................................................................................... 4 2.2 Arrangements for the audit .............................................................................. 6 2.3 Conduct of the audit ........................................................................................ 6 2.4 Submissions received...................................................................................... 9 Chapter 3 Land Use and Human Settlements............................................12 3.1 Land use ....................................................................................................... 12 3.2 Sites of pollution and potential contaminants................................................. 28 3.3 Soil erosion.................................................................................................... 32 3.4 Population settlements and patterns.............................................................. 40 3.5 Community attitudes, aspirations and engagement ....................................... 42 Chapter 4 Biodiversity and Habitats ..........................................................47 4.1 Macroinvertebrates........................................................................................ 47 4.2 Fish ............................................................................................................... 51 4.3 Riparian vegetation........................................................................................ 56 4.4 Native vegetation........................................................................................... 62 4.5 Fire................................................................................................................ 68 4.6 Wetlands ....................................................................................................... 75 4.7 Physical form................................................................................................. 84 Chapter 5 Water Availability .......................................................................89 5.1 Surface water flows ....................................................................................... 89 5.2 Environmental flows .................................................................................... 103 5.3 Groundwater availability .............................................................................. 109 Chapter 6 Water Quality ............................................................................115 6.1 Ecosystem and raw water quality ................................................................ 115 6.2 Nutrient load................................................................................................ 141 6.3 Cyanobacterial blooms ................................................................................ 154 6.4 Trend assessment....................................................................................... 165 6.5 Integration of water quality and ecosystem health indicators ....................... 173 Chapter 7 Audit Recommendations ..........................................................174 7.1 Overview ..................................................................................................... 174 7.2 Review of the 2007 recommendations......................................................... 174 7.3 Recommendations from the 2010 audit ....................................................... 183 Acronyms ....................................................................................................186 References ..................................................................................................189 Volume 2: Appendices Appendix A: Roles and responsibilities of stakeholders Appendix B: List of parties that responded to the audit Appendix C: Sub-catchment summaries Appendix D: Major projects in the Catchment Appendix E: Water sharing plan management zones Appendix F: Flow exceedance curves Appendix G: River Water Quality Summary The Sydney Water Catchment Management Act 1998 (the Act) is the legislation that defines the roles, functions and objectives of the Sydney Catchment Authority. The Sydney Water Catchment Management Amendment Act 2007 requires an audit of the state of the land of the Sydney Drinking Water Catchment (the Catchment) be undertaken every three years, and that a report on this audit be submitted to the Minister responsible for the Sydney Catchment Authority (SCA). The Department of Environment, Climate Change and Water (DECCW) was requested by the Minister to nominate an Auditor to undertake the 2010 audit covering the period 1 July 2007 to 30 June 2010. The audit’s Terms of Reference were to: • assess the state of the Catchment having regard to the catchment health indicators approved under Section 42 of the Act, applicable as at the time of the audit • conduct the audit having regard to the current methodology used in the NSW State of the Environment (SoE) reporting • consult with stakeholders inside and outside the Catchment to seek information and data that may assist with the audit and seek comments relating to the state of the catchment • include long-term trend analysis. The report, Development of Catchment Health – indicators for the drinking water catchments – Sydney, the Illawarra, Blue Mountains, Southern Highlands and Shoalhaven (NOW 2009) listed the catchment health indicators, outlined the process for indicator selection, summarised the recommended methodology for data collection and identified the agencies responsible for collecting indicator data. In this audit, consistency with current methods for SoE reporting for NSW was achieved by using the Pressure-State-Response (PSR) model of environmental reporting. Eighteen indicators were used to quantify and simplify the complex nature of environmental states and pressures and their interactions. The indicators were grouped into four broad themes: Land Use and Human Settlements; Biodiversity and Habitats; Water Availability; and Water Quality. Compared with previous audits, a number of changes were required for the 2010 audit because of: • changes in the indicators used, including the use of new indicators • changes to the period of assessment (three years as opposed to two years in previous audits) • the requirement for long-term trend analysis. Some indicators are less well-developed than others. The change to a three-year reporting timeframe also makes comparisons with previous audits (which covered a two-year period) less meaningful (e.g. when comparing the number of exceedances). The approach taken for such comparisons was, wherever possible, to split long-term data into successive three-year periods and then compare the results. Long-term trend analyses were based on analysis and comparison of percentiles during these successive three-year periods. Flow exceedance curves were also considered when comparing flow in the current audit period with flow in earlier time periods. The Catchment has been split into 27 sub-catchments. Information was compiled by each sub-catchment to highlight their condition and the pressures on them. However, some indicators did not have sufficient spatial resolution to report at the sub- catchment scale and so they were assessed at either the basin (Hawkesbury–