OUTCOMES (Matters in red link to the Basin-wide environmental watering strategy, MDBA 2014a) OBJECTIVES FOR LOWER MURRAY–DARLING ASSETS IN-CHANNEL ASSETS END OF SYSTEM OFF-CHANNEL ASSETS River Murray from Euston to Lower Lakes Lower Darling River Great Darling Coorong, Lower Lakes and Murray Mouth Hattah Lakes Floodplain and wetlands from Euston to South Australian border Floodplain and wetlands from South Australian border to Lower Lakes INVERTEBRATES Provide habitat to support increased microinvertebrate and macroinvertebrate survival, diversity, abundance and condition. OTHER Provide habitat to support survival, maintain condition and provide recruitment opportunities for frogs and turtles. CONNECTIVITY Maintain baseflows and increase overall flows in the River Murray. Maintain longitudinal connectivity along the Lower Darling and Murray rivers, including connectivity between the two systems in order to fulfil important environmental functions, such as nutrient and sediment transport, organism dispersal and water quality. Maintain lateral connectivity through contributing to an increase in the frequency of freshes, bankfull and lowland floodplain flows. Maintain latitudinal connectivity (within constraints) to wetlands and floodplains, by contributing an increase in the frequency of lowland floodplain flows. Improve the connection of the River Murray to the Coorong and the sea, through supporting increased barrage flows and Murray mouth openness. PROCESSES Increase primary productivity, nutrient and carbon cycling, biotic dispersal and movement. Increase transport of organic matter, salt and nutrients downstream and out the Murray Mouth. WATER QUALITY Maintain water quality and provide refuge habitat from adverse water quality events (e.g. blackwater). Maintain salinity regimes below critical thresholds for key flora and fauna in the Lower Lakes and Coorong through supporting the export of salt through the Murray Mouth. Increase mobilisation and export of salt from the River Murray system. RESILIENCE Maintain drought refuge habitat and maintenance/condition of native biota (e.g. fish and other aquatic fauna). Information sourced from: MDBA (2014a); Department of the Environment (2011 and unpublished); MDBA (2012a-i); DELWP (2015), Department of Environment, Water and Natural Resources (2015).
Key - events in previous years means demand was met by Commonwealth environmental water or any other source means demand was partially met by Commonwealth environmental water or any other source (may be used to indicate infrastructure assisted delivery) means water not provided (or not required) Note that not all demands require water every year; drying phases are important for floodplains and temporary wetlands or streams Key - potential watering in 2017-18 means a high priority for Commonwealth environmental watering (full or partial contribution, and subject to seasonal and operational considerations) means a secondary priority for Commonwealth environmental watering, likely to be met via other means (other water holders, or natural flows) means a low priority for Commonwealth environmental watering Key - urgency of environmental demands means critical demand i.e. urgent need for water in that particular year to manage risk of irretrievable loss or damage means high demand for water i.e. needed in that particular year means moderate demand for water i.e. water needed that particular year and/or next means low demand for water i.e. water generally not needed that particular year means very low demand for water i.e. water generally not needed that particular year or the following year demand is considered at a generalised scale; there may be specific requirements that are more or less urgent within the flow regime
Specific outcomes for key species for the Lower Murray include: Species Specific outcomes In-scope for C’th watering? Diadromous species (Congolli, short-headed and pouched lamprey) Upstream expansion facilitated through flows to operate fishways Yes Flathead galaxias (Galaxias rostratus) Expand the core range in the wetlands of the River Murray Yes Freshwater catfish (Tandanus tandanus) - Yes Golden Perch (Macquaria ambigua) A 10–15 per cent increase of mature fish (of legal take size) in key populations Yes Murray cod (Maccullochella peelii peelii) A 10–15 per cent increase of mature fish (of legal take size) in key populations Yes Murray hardyhead (Craterocephalus fluviatilis) Expand the range of at least two current populations: Establish 3–4 additional populations, with at least two of these to be within the lower Murray conservation unit and a further population potentially within the Kerang Lakes region Yes Olive perchlet (Ambassis agassizii) Olive perchlet are considered extinct in the southern Basin. Reintroduction using northern populations is the main option for recovery. Candidate sites may result from improved flow that reinstates suitable habitat in the River Murray Restoration of flow to River Murray could support the future reintroduction of the species Silver perch (Bidyanus bidyanus) Improve core range in at additional locations, with candidate sites including lower Darling Core range is within Mid-Murray region. Only in scope if additional populations are established Southern purple-spotted gudgeon (Mogurnda adspersa) Expand the range of current populations (including Jury Swamp) Yes Southern pygmy perch (Nannoperca australis) Establish additional populations in the Lower Lakes Only if additional populations are established Trout cod (Maccullochella macquariensis) For the connected population of the Murrumbidgee–Murray–Edwards, continue downstream expansion Yes Two-spined blackfish (Gadopsis bispinosus) Establish additional populations (no specific locations identified) Yes Yarra pygmy perch (Nannoperca obscura) Expand the range of current populations including the Lower Lakes/Coorong region Yes
Broad Asset Indicative demand Applicable level(s) of resource availability Very Low Low Moderate High Very High Floodplain and wetlands from Euston to South Australian border 30,000 ML/day @ Lock 8 for 30-60 days targeting low lying wetlands and anabranches, or portion via infrastructure 50,000-60,000 ML/day @ Lock 8 for 60-120 days targeting river red gum forest, lignum shrubland and associated wetlands, or portion via infrastructure Infrastructure delivery to a portion equivalent to 80,000 ML/d @ Lock 8 targeting river red gum and black box woodland and associated wetlands 5 Delivery via Lindsay-Mulcra-Wallpolla Floodplain works: Contribute flows via works to inundate low lying wetlands and anabranches, river red gum forest and/or black box woodland. 6. Infrastructure Delivery: Mallee Wetlands: Contribute flows via wetland regulators and/or pumping to inundate semi-permanent, temporary and ephemeral wetlands 7. Contribution to Overbank Flows: Contribute to flows to reconnect river with river red gum forest and lignum shrubland, subject to appropriate trigger Floodplain and wetlands from South Australian border to Lower Lakes 40 – 50 GL/day @ South Australian border for at least 30 days targeting river red gum forest, tea tree, lignum, river cooba and associated wetlands, or priority areas via infrastructure 50 -60 GL/day @ South Australian border for at least 30 days targeting river red gum forest, tea tree, lignum, river cooba and associated wetlands, or priority areas via infrastructure Infrastructure delivery to a priority area equivalent to 60 – 70 GL/day @ South Australian border targeting black box, cooba, lignum and chenopod and associated wetlands 8. Infrastructure Delivery: Chowilla Floodplain: Use Chowilla Floodplain infrastructure to deliver pulse flows to creeks and inundate parts of the floodplain 9. Infrastructure Delivery: Lower Murray Wetlands: Contribute flows via wetland regulators, pumping and/or weir pool manipulation to inundate semi-permanent, temporary and ephemeral wetlands 10a. Contribution to hydrodynamic diversity: Contribute to underwrite weirpools where lowering has been undertaken to increase diversity in hydrology, subject to appropriate trigger 10b. Contribution to Overbank Flows: Contribute to flows to re-connect river with river red gum forest and lignum shrubland, subject to appropriate trigger
Broad Asset Indicative demand Applicable level(s) of resource availability Very Low Low Moderate High Very High Coorong Lower Lakes and Murray Mouth Minimum barrage flow of 650 GL/yr Barrage flows of 2,000 GL/yr required to achieve salinity target in Lake Alexandrina Barrage flows of at least 2 500 GL over two years to avoid damage and protect habitat conditions within the Coorong Barrage flows of 6,000 GL every three years to maintain and improve habitat conditions within the Coorong. 11a. Seasonal Lake Level Variation: Between 0.40 m AHD and 0.80 m HD annually. Fishway Flows: Maintain minimum fishway flows Differential Barrage releases: To provide for connectivity between the Coorong, Lower Lakes and the Murray Mouth, improve Coorong water quality and maintain suitable estuarine conditions in the North lagoon and Murray Mouth Barrage flows of 10 000 GL every seven years to improve habitat conditions within the Coorong 11b. Seasonal Lake Level Variation: Between 0.50 m AHD and 0.85 m AHD one in three years Fishway Flows: Maintain minimum fishway flows Differential barrage releases: To provide for seasonally appropriate water levels in the Coorong and connectivity between the Lower Lakes and the Murray Mouth