Ovens Region
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Fishing on the Ovens River at Porepunkah, Victoria Summary of OVENS 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 Ovens region. THE REGION The Ovens region is named after one of its major waterways. The Ovens River runs from the Great Dividing Range in north- eastern Victoria to Lake Mulwala on the River Murray. The Ovens is recognised as one of the last unregulated rivers in Victoria. The second major river in the region, the King, joins the Ovens near Wangaratta. The main towns in the region are Wangaratta, Myrtleford, Beechworth and Bright. All these towns, except Beechworth, secure their water supplies from within the region. Water USE AND environMentaL HEALTH The rivers of the region supply water for a The Authority has compiled the current limits variety of irrigated agriculture, including for all forms of water extraction in the Murray- vineyards and pasture production. The Darling Basin. For surface water these current dairying, beef-cattle farming and grape- diversion limits include watercourse diversions growing industries use the most water in the for town and community water supplies, Ovens region. irrigation and industries, floodplain harvesting, In the Ovens region, there are a number and interception activities such as farm dams of factors indicating moderate ecological and forestry plantations. For groundwater they condition. For example: Vegetation condition include all water diverted from the aquifers scores as moderate given the proportion of of the area. Current diversions are limited by remnant cover in the catchment and along existing transitional and interim water resource watercourses. Fish scores are poor with exotic plans where these are in place. These are fish making up a large proportion of biomass. existing plans, prepared by Basin states, and The hydrological condition for the Ovens is recognised under the Water Act 2007 (Cwlth) good while stream condition is moderate, with (the Act). Where there are no existing plans, a significant proportion in good condition. or plans do not apply to certain types of water Macroinvertebrate diversity is moderate to extraction, the current diversion limit reflects high. The water quality in the Ovens River is the current level of use. in very good to excellent condition, but some The surface water long-term average current tributaries throughout the upper Ovens River diversion limit for the Basin as a whole has have high turbidity levels and high nutrient been estimated at around 13,700 GL/y and concentrations, with low salinity levels. at 83 GL/y for the Ovens region. The Basin wide groundwater long-term average current Assessing environMentaL Water NEEDS diversion limit is 1,786 GL/y. Many of the environmental assets and functions of the Murray-Darling Basin have been degraded by the over-extraction Ovens Region surface water of water from the Basin’s rivers. The Act Current Diversion Limit (GL/y) and Basin Plan seek to address the over- Interceptions Watercourse diversions Total extraction of water to restore and maintain 58 25 83 the Basin’s key environmental assets and key ecosystem 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-dependent 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 Bright Bridge over Ovens River, Victoria environmental water requirements of rivers, and system wide processes such as connectivity between rivers and floodplains. Together, these assessments included specific this range. This range takes into account all the analysis of flows at 106 hydrologic indicator available evidence, the quality of that evidence, sites across the Basin (88 sites to assess the and the inherent uncertainty of modelling. water needs for the Basin’s key ecosystem The Authority has determined that 3% of the functions and 18 to assess the water needs for current diversion limit (around 410 GL/y for key environmental assets), as well as analysis the Basin as a whole and around 2 GL/y for of end of system flows in each region. the Ovens region) is an appropriate allowance The environmental water requirements at a to account for the effect of climate change Basin scale have been estimated between on surface water SDL proposals. The SDL 22,100 GL/y and 26,700 GL/y (an increase proposals for groundwater do not include a between 3,000GL/y to 7,600GL/y from the climate change component. 19,100 GL/y currently available for the The SDL proposals would require a reduction environment). in the current long-term average surface In the Ovens, 101 key environmental assets water diversion limit at the Basin scale from have been identified. Of the 106 hydrological 13,700 GL per year to between 10,700 GL and indicator sites across the Basin the Ovens 9,700 GL per year (reduction between 3,000 GL region contains 4 hydrological indicator sites and 4,000 GL per year or 22% to 29%). for key ecosystem functions. For the Ovens region this would equate to The environmental water requirements for reduction in the current long-term average the Ovens region have been estimated at surface water diversion limit from 83 GL/y to 13 GL/y (13 GL/y are currently available for between 73 GL and 72 GL per year (reduction the environment). However, reductions in between 10 GL and 11 GL per year or 12% current diversion limits may still be required to 13%). considering the environmental water needs of The SDL proposals would also require a downstream regions. reduction in the current long-term average Further information on assessing the groundwater diversion limit at the Basin scale environmental water requirements of the Basin by an aggregate 186 GL or an average reduction is available at http://www.mdba.gov.au/basin_ of 10% across the Basin. The reductions in plan/water-assessment-report. current diversion limits are required in only 11 of the 78 groundwater SDL areas. No SUstainaBLE DIVERSION LIMIT ProPOSALS reductions are proposed for the remaining AT THE BASIN AND REGIONAL SCALE 67 groundwater SDL areas where the current The Authority is required to establish new diversions are assessed as sustainable. long-term average SDLs for surface water SDL proposals for the surface water and and groundwater. SDLs represent the long- groundwater SDL areas of the Ovens region are term average amount of water which can be set out on page 5. used for consumptive purposes after meeting the environmental water needs that have SUPPorting coMMUNITIES been identified. Across the Basin, 29 surface The Murray–Darling Basin Authority water and 78 groundwater SDL areas have acknowledges that implementing SDLs been identified to cater for state boundaries, may have significant social and economic hydrologic and hydrogeologic units used by implications for individual entitlement holders Basin states for their existing and proposed and communities across the Basin. water resource plans. SDLs will be set for all diversions in each of these SDL areas. However, the Australian Government has committed to recovering sufficient water access In the Guide, the Authority presents the SDLs entitlements to fully offset the impact of SDLs as a range of scenarios for discussion at this across the Basin, including the Ovens region. stage, rather than choosing a particular value in This will be achieved through a combination of purchasing entitlements in the market and investments in more efficient irrigation infrastructure. Consequently, should these targets be met, there are likely to be no reductions in individual water entitlement holder allocations. Ovens River near Porepunkah, Victoria SUSTAINABLE DIVERSION LIMIT PROPOSALS OVENS REGION SURFACE WATER GROUNDWATER There is one surface water SDL area There are two groundwater SDL areas wholly or within the Ovens region. partially contained within the Ovens region. 1) Ovens 1) Ovens–Kiewa Sedimentary Plain Current diversion limit 83 GL/y Current diversion limit 14.7 GL/y SDL proposal from 73 GL/y SDL proposal 14.7 GL/y to 72 GL/y Reduction Nil Reduction from 10 GL/y 2) Ovens Highlands (12%) to Current diversion limit 3.2 GL/y 11 GL/y (13%) SDL proposal 3.2 GL/y Reduction Nil Warrego er Riv Condamine−Balonne o M Condamine−Balonne eg rr a a r a W n o Moonie a Charleville R i v Roma e r k e River e ne r i am Paroo C d on BRISBANE a l C Toowoomba a l r l iver e a nie R r v g o ive i Cunnamulla St George Mo ir R n e R W u o o M QLD r ver iver Goondiwindi a i R R on P oa w lg ar u B C er r Se SA iv e ver Barwon−Darlining R iv Moree G n R ie R w ive rr n yd r i a ir B rr R NSW a iv N e Bourke r Border RiRivers Nam o i C Narrabri R a iv Lower Darling r s e C e t r iv M l Gwydirir e o R g a r x e Tamworth lin c s r B q a a u g C o a h r D g r e a i R e e n i R v k Murray e R i Broken Hill v r i e er v r r Riv e Talbraga r Namoii Dubbo Ivanhoe chlan River La Orange Macquarie−Castlereagh Forbes B Cowra la SYDNEY n River d Mur Mildura ray Griffith C r e Renmark urrumbidge e M e R k ive ADELAIDE r Lachlalan B illabo Murray Bridge ng C Wagga Wagga CANBERRA