'Near to final' draft for independent review - 2 May 2016 Table 3: Site-specific flow indicators for large in-channel freshes for the Barwon- Darling UEA. In this table, frequency is the percentage of years in which there is the flow event. Frequency range is shown as low uncertainty to high uncertainty Magnitude Dur. Freq. Basis of magnitude Basis of duration Timing Basis of timing Basis of frequency (ML/d) days range Trigger opportunity for large- To improve mixing of scale fish movement (Walgett The typical duration of Minimum of 1 Provide at least populations (genetic 10,000 to Wilcannia) through drown this size flow event at flow event one opportunity 80% - diversity) and improved (Bourke 14 out of barriers; improved Bourke and the hatch between Aug outside the two 60% conditions for breeding, gauge) access to ideal habitat (two time of most native fish - May coldest months especially for flow thirds of snags, most benches species dependent specialist fish and a few wetlands) Consistent with Ideal spawning and The minimum duration In addition to above, provides spawning season recruitment opportunities for Murray cod to breed Minimum of 2 10,000 peak of 15,000 ML/d for five of flow dependent in about 3 out of 10 (from nest development flow events 35% – (Bourke days, considered sufficient to 20 fish, with second years. Linked to to dispersal of larvae); between Aug 25% gauge) cue flow dependent specialist flow event biological requirements sufficient for other - May fish breeding enhancing of flow dependent groups of native fish recruitment specialist fish To provide breeding In addition to above, provides opportunities for access to all snags in the Minimum of 1 extensive breeding of in- 21,000 Bourke to Louth reach to flow event channel specialists fish - (Louth support in-channel specialist 20 As above As above 40% between Aug linked to biological gauge) breeding, and access to an - May requirements including increased number of those of medium to long anabranches and wetlands. lived fish Considered to Extensive inundation of in- Based on evidence Minimum of 1 Based on a percentage 20,000 provide channel benches to support in- showing carbon and flow event 60% - of the frequency under (Wilcannia 7 productivity stream primary productivity, nutrients are rapidly any time of 45% without development gauge) benefits for fish food supply and habitat access absorbed the year conditions any time of year Page 46
'Near to final' draft for independent review - 2 May 2016 Table 3: Site-specific flow indicators for large in-channel freshes for the Barwon- Darling UEA. In this table, frequency is the percentage of years in which there is the flow event. Frequency range is shown as low uncertainty to high uncertainty Magnitude (ML/d) Basis of magnitude Dur. days Basis of duration Timing Basis of timing Freq. range Basis of frequency 10,000 (Bourke gauge) Trigger opportunity for large- scale fish movement (Walgett to Wilcannia) through drown out of barriers; improved access to ideal habitat (two thirds of snags, most benches and a few wetlands) 14 The typical duration of this size flow event at Bourke and the hatch time of most native fish species Minimum of 1 flow event between Aug - May Provide at least one opportunity outside the two coldest months 80% - 60% To improve mixing of populations (genetic diversity) and improved conditions for breeding, especially for flow dependent specialist fish 10,000 (Bourke gauge) In addition to above, provides peak of 15,000 ML/d for five days, considered sufficient to cue flow dependent specialist fish breeding 20 The minimum duration for Murray cod to breed (from nest development to dispersal of larvae); sufficient for other groups of native fish Minimum of 2 flow events between Aug - May Consistent with spawning season of flow dependent fish, with second flow event enhancing recruitment 35% – 25% Ideal spawning and recruitment opportunities in about 3 out of 10 years. Linked to biological requirements of flow dependent specialist fish 21,000 (Louth gauge) In addition to above, provides access to all snags in the Bourke to Louth reach to support in-channel specialist breeding, and access to an increased number of anabranches and wetlands. 20 As above Minimum of 1 flow event between Aug - May As above 40% To provide breeding opportunities for extensive breeding of in- channel specialists fish - linked to biological requirements including those of medium to long lived fish 20,000 (Wilcannia gauge) Extensive inundation of in- channel benches to support in- stream primary productivity, food supply and habitat access 7 Based on evidence showing carbon and nutrients are rapidly absorbed Minimum of 1 flow event any time of the year Considered to provide productivity benefits for fish any time of year 60% - 45% Based on a percentage of the frequency under without development conditions Page 46
EWR-Barwon-Darling-draft.docx