Macquarie Marshes near Warren,

Summary of MACQUARIE– CASTLEREAGH REGION From the Guide to the proposed Basin Plan

This publication summarises proposals outlined in the Guide to the proposed Basin Plan as they relate to the Macquarie–Castlereagh region.

The region The Macquarie–Castlereagh region varies from steep terrain in the east to open plains in the west where the Ramsar-listed Macquarie Marshes are located. The region is based around the Macquarie, Castlereagh, Cudgegong and Bogan and the main population centres are , Wellington, Mudgee, Orange and Bathurst. Water use and environmental health Timor Dam on the upper Castlereagh provides water for and the lower The Authority has compiled the current limits for receives regulated water from the Macquarie by all forms of water extraction in the Murray- Darling diversions through the Albert Priest Canal, which Basin. For surface water these current diversion also supplies water to and Cobar. In addition, limits include watercourse diversions for town and there is a transfer out of the Macquarie–Castlereagh community water supplies, irrigation and industries, region to the catchment for floodplain harvesting, and interception activities industrial and urban use in Lithgow and the Blue such as farm dams and forestry plantations. For Mountains areas. groundwater they include all water diverted from the of the area. Current diversions are limited There are a number of factors indicating very by existing transitional and interim water resource poor ecological condition in the Macquarie – plans where these are in place. These are existing Castlereagh region. For example: Vegetation plans, prepared by Basin states, and recognised condition is moderate with over 50% remnant cover under the Water Act 2007 (Cwlth) (the Act). Where in the catchment and along watercourses. Native there are no existing plans, or plans do not apply fish populations are extremely poor with a high to certain types of water extraction, the current percentage of exotic species captured in sampling. diversion limit reflects the current level of use. Hydrological condition in the Macquarie and Castlereagh valleys is considered moderate to good The surface water long-term average current while stream condition is extensively modified and diversion limit for the Basin as a whole has been significantly impaired. Overall, macroinvertebrate estimated at around 13,700 GL/y and at 735 GL/y for diversity is poor. The major water quality issues in the Macquarie-Castlereagh region. The Basin wide the Macquarie-Castlereagh region are increasing groundwater long-term average current diversion trends in the levels of salinity, turbidity, nutrients, limit is 1,786 GL/y. pesticides and thermal pollution. Macquarie-Castlereagh Region surface water Current Diversion Limit (GL/y) Assessing environmental water needs Interceptions Watercourse Diversions Total Many of the environmental assets and functions 310 425 735 of the Murray-Darling Basin have been degraded The region’s water is diverted or extracted for by the over-extraction of water from the Basin’s industrial and urban water use as well as for stock rivers. The Act and Basin Plan seek to address the and domestic purposes and for irrigation of cotton, over-extraction of water to restore and maintain the oilseeds, cereals, citrus, grapes, stonefruit and Basin’s key environmental assets and key ecosystem lucerne. functions. To determine sustainable diversion limit (SDL) proposals it is necessary to work out how much water is needed to sustain the health of the Basin’s river systems, wetlands and floodplains. To do this, the Authority has undertaken an assessment of the environmental water requirements of key environmental assets and key ecosystem functions across the Murray-Darling Basin. In the most part, the assets assessed are large flood-dependant wetland and floodplain systems that support populations of waterbirds and fish, and large forests and woodlands. The assessment of key ecosystem functions gave particular attention to the environmental water requirements of rivers, and Cotton crop harvested near Warren, New South Wales system wide processes such as connectivity between rivers and floodplains. Together, these assessments included specific Castlereagh region) is an appropriate allowance analysis of flows at 106 hydrologic indicator sites to account for the effect of climate change on across the Basin (88 sites to assess the water needs surface water SDL proposals. The SDL proposals for the Basin’s key ecosystem functions and 18 for groundwater do not include a climate change to assess the water needs for key environmental component. assets), as well as analysis of end of system flows in each region. The SDL proposals would require a reduction in the current long-term average surface water diversion The environmental water requirements at a Basin limit at the Basin scale from 13,700 GL per year to scale have been estimated between 22,100 GL/y between 10,700 GL and 9,700 GL per year (reduction and 26,700 GL/y (an increase between 3,000GL/y to between 3,000 GL and 4,000 GL per year or 22% to 7,600GL/y from the 19,100 GL/y currently available 29%). for the environment). For the Macquarie-Castlereagh region this would In the Macquarie-Castlereagh region, 20 key equate to reduction in the current long-term environmental assets have been identified. Of the average surface water diversion limit from 735 GL/y 106 hydrological indicator sites across the Basin to between 631 GL and 600 GL per year (reduction the Macquarie-Castlereagh region contains eight between 104 GL and 135 GL per year or 14% to 18%). hydrological indicator sites for key ecosystem functions and one hydrologic indicator site for The SDL proposals would also require a reduction key environmental assets. This is the Macquarie in the current long-term average groundwater Marshes diversion limit at the Basin scale by an aggregate 186 GL or an average reduction of 10% across the The environmental water requirements for the Basin. The reductions in current diversion limits Macquarie-Castlereagh region have been estimated are required in only 11 of the 78 groundwater SDL between 1,922 GL/y and 2,091 GL/y (an increase areas. No reductions are proposed for the remaining between 20 GL/y and 189 GL/y from the 1,902 GL/y 67 groundwater SDL areas where the current currently available for the environment) diversions are assessed as sustainable.

Further information on assessing the environmental SDL proposals for the surface-water and water requirements the Basin is available at http:// groundwater SDL areas of the Macquarie- www.mdba.gov.au/basin plan/water-assessment- Castlereagh region are set out on page 5. report. Supporting communities Sustainable diversion limit proposals at The Murray–Darling Basin Authority acknowledges the Basin and regional scale that implementing SDLs may have significant social The Authority is required to establish new long-term and economic implications for individual entitlement average SDLs for surface water and groundwater. holders and communities across the Basin. SDLs represent the long-term average amount of water which can be used for consumptive purposes However, the Australian Government has committed after meeting the environmental water needs that to recovering sufficient water access entitlements have been identified. to fully offset the impact of SDLs across the Basin, including the Macquarie-Castlereagh region. This In the Guide, the Authority presents the SDLs as will be achieved through a combination of purchasing a range of scenarios for discussion at this stage, entitlements in the market and investments in more rather than choosing a particular value in this efficient irrigation infrastructure. range. This range takes into account all the available evidence, the quality of that evidence, and the Consequently, should these targets be met, there inherent uncertainty of modelling. are likely to be no reductions in individual water entitlement holder allocations. The Authority has determined that 3% of the current diversion limit (around 410 GL/y for the Basin as a whole and around 22 GL/y for the Macquarie- Warrego

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Macquarie−Castlereagh region Basin Plan regions capital city main town main rivers state border 0 100200 km SUSTAINABLE DIVERSION LIMIT PROPOSALS MACQUARIE–CASTLEREAGH REGION

SURFACE WATER GROUNDWATER

There is one surface-water SDL area in There are thirteen groundwater SDL 8) Lower Macquarie Alluvium the Macquarie-Castlereagh region. areas wholly or partly contained within Current diversion limit 69.3 GL/y the Macquarie-Castlereagh region. SDL proposal 41.9 GL/y Reduction 27.4 GL/y 1) Macquarie–Castlereagh or 40% 1) Bell Valley Alluvium Current diversion limit 735 GL/y Current diversion limit 2.2 GL/y 9) NSW Alluvium above the SDL proposal from 631 GL/y SDL proposal 2.2 GL/y Great Artesian Basin to 600 GL/y Reduction Nil Current diversion limit 1.2 GL/y Reduction from 104 GL/y SDL proposal 1.2 GL/y (14%) to 135 2) Castlereagh Alluvium Reduction Nil – potential GL/y (18%) Current diversion limit 0.4 GL/y for unassigned water SDL proposal 0.4 GL/y Reduction Nil 10) Orange Basalt Current diversion limit 6.9 GL/y 3) Collaburragundry–Talbragar Alluvium SDL proposal 6.9 GL/y Current diversion limit 3.7 GL/y Reduction Nil – potential for unassigned SDL proposal 3.7 GL/y water Reduction Nil

11) Upper Darling Alluvium 4) Cudgegong Alluvium Current diversion limit 2.4 GL/y Current diversion limit 1.6 GL/y SDL proposal 2.4 GL/y SDL proposal 1.6 GL/y Reduction Nil – potential Reduction Nil for unassigned water 5) Eastern Porous Rock: Macquarie–Castlereagh 12) Upper Macquarie Alluvium Current diversion limit 5.2 GL/y Current diversion limit 13.7 GL/y SDL proposal 5.2 GL/y SDL proposal 13.7 GL/y Reduction Nil Reduction Nil 6) Lachlan Fold Belt: Macquarie–Castlereagh 13) Warrumbungle Basalt Current diversion limit 47.7 GL/y Current diversion limit 0.5 GL/y SDL proposal 47.7 GL/y SDL proposal 0.5 GL/y Reduction Nil Reduction Nil – potential for unassigned water 7) Liverpool Ranges Basalt Current diversion limit 2.7 GL/y SDL proposal 2.7 GL/y Reduction Nil Crops on a farm near Mudgee, New South Wales

Further information and feedback About MDBA For further information on the Guide to the The Murray–Darling Basin Authority (MDBA) proposed Basin Plan, visit the MDBA website at: is the statutory agency that manages, in conjunction with the Basin states, the Murray– www.mdba.gov.au Darling Basin’s water resources in the national interest. Our website also provides details about community MDBA is responsible for preparing information sessions and ways to provide feedback and overseeing a legally-enforceable on the Guide. management plan — the Basin Plan. You can also find out about upcoming events The Basin Plan will: and information releases by subscribing to our • optimise social, economic and environmental outcomes engagement email and the monthly E-newsletter. • set and enforce environmentally You may also phone us on 1800 230 067 (free call) sustainable limits on the quantities of or write to us at: water that may be taken from Basin water resources Murray–Darling Basin Authority • set Basin-wide environmental, water quality and salinity objectives GPO Box 3001, Canberra ACT 2601. • develop efficient water trading regimes across the Basin • set requirements for state water resource plans • improve water security for all Basin users. This document has been prepared by PHOTOGRAPHER CREDITS the Murray–Darling Basin Authority for public consultation purposes, using the Bill Johnson: Page 1 best efforts to ensure that the material it presents is current and accurate. Arthur Mostead: Page 2 The opinions, comments and analysis (including those of third parties) expressed Irene Dowdy: back page in this document are for consultation purposes only.