'Near to final' draft for independent review - 9 May 2016 ` Multiple distributary river channels Snags and benches Wetlands During no -flow periods, waterholes provide drought refuge. Periods of no flows are more common in the Lower Balonne River Floodplain than most systems. Small in-channel freshes provide longitudinal connectivity down the river channels. This is important for maintaining, and providing access to, in-stream habitats. Flowing water creates hydraulic diversity, such as eddies near snags. Freshes are also important for cycling sediment and nutrients between different parts of the river channel. Larger in-channel freshes are important for fish migration when they trigger movement and drown out in-stream barriers. Freshes can replenish soil water/bank storage for riparian vegetation and inundate benches, anabranches and snags which are important for fish spawning. Bankfull flows reshape the channel creating and maintaining habitats such as pools, bars and benches. Small overbank flows fill the river channel and inundate the riparian zone, anabranches, flood-runners, wetlands and the floodplain. These flows provide opportunities for some birds to breed and allow fish, frogs, turtles and invertebrates to move from the river to the wider floodplain next to the river, and back again. Larger overbank flows provide extensive lateral connectivity with the floodplain. These flows provide water and nutrients to floodplain vegetation communities. Flows that reach these areas are also very important for the dispersal of seeds and aquatic animals. Figure 4. Key components of the flow regime of rivers like those on the Lower-Balonne River Floodplain UEA, and connection with ecological functions and process Page 18
'Near to final' draft for independent review - 9 May 2016 Table 2: Lower Balonne River Floodplain UEA site-specific flow indicators related to drought refuges. In this table, frequency is the maximum number of days between events. The frequency range is shown from low uncertainty to high uncertainty. Magnitude: flow (ML/d) Basis of magnitude Duration (days) Basis of duration Timing Basis of timing Frequency range Basis of frequency Any flow, taken as 2 ML/d, Culgoa River at Weilmoringle Upstream waterhole refuges are topped up as there is an observed flow at the downstream gauge 1 Minimum time step in the model for a flow to be observed Any time of year The primary aim is to break up long dry spells: timing is not important. 350 - 430 days (maximum period between flow events) Set at the reach scale - based on modelled persistence time to a depth of 0.5 m in four waterholes (350 days), or two waterholes (430 days) in the Culgoa River Any flow, taken as 2 ML/d, Narran River at Narran Park As above As above As above As above As above 350 - 470 days (maximum period between flow events) Set at the reach scale - based on modelled persistence time to a depth of 0.5 m in four waterholes (350 days), or two waterholes (470 days) in the Narran River Page 50
'Near to final' draft for independent review - 9 May 2016 Table 3: Site-specific flow indicators for small in-channel freshes for the Lower Balonne River Floodplain UEA. In this table, frequency is the percentage of years in which there is a corresponding flow event. The frequency range is shown from low uncertainty to high uncertainty. Magnitude: flow (ML/d) Basis of magnitude Duration (days) Basis of duration Timing Basis of timing Freq. range Basis of frequency 1,000 (Culgoa River at Brenda) To provide access to in-stream habitat along with a range of hydraulic conditions. In- channel inundation beyond the waterholes. This flow would provide relatively small-scale movement opportunities, perhaps to neighbouring pools. There may also be some short term connection between distributaries, subject to barriers 7 Duration to achieve connectivity along the main distributary channels and potential for drift of biota such as fish larvae. Any time of the year At any time of year would provide benefits of connection and improved habitat condition. 90% – 80% The condition of aquatic biota benefits from regular flows for productivity in most years, particularly for short-lived aquatic species. Maintenance of habitat and regular short scale movement opportunities for aquatic species. 1,700 (Narran River at Wilby Wilby) In addition to the above, to trigger fish movement of flow dependent specialists, for dispersal and spawning. Provides both a 2 m rise and an average velocity (0.3 metres per second). 14 Linked to the typical duration of this size event, and to the hatch time for native fish eggs generally. Aug - May Fish response expected above the critical water temperature threshold of 15 degrees Celsius. 60% - 40% Re-colonisation of aquatic species. Provide regular opportunities for mixing of populations (genetic diversity) 3,500 (Culgoa River at Brenda) As above As above As above As above As above As above As above Page 58
'Near to final' draft for independent review - 9 May 2016 Table 9: Site-specific flow indicators for the Narran Lakes UEA. All volumes are measured at the Wilby Wilby gauge on the Narran River. The frequency, unless otherwise indicated, is the average number of years between events. The frequency range is shown from low uncertainty to high uncertainty. Magnitude: volume (ML) Basis of magnitude Duration (days) Basis of duration Timing Basis of timing Frequency (years) Basis of frequency 25,000 Habitat vigour of lignum in northern lakes zone, core rookery habitat 60 Required duration to fill the lakes of northern lakes zone Any time of year, preferably summer Summer dominated system, most flows tend to occur in summer 1 - 1.3 Frequency of inundation for vigour of large clumps of lignum in key rookery habitats: around 60% cover 50,000 Habitat vigour of lignum surrounding core habitat, some of northern floodplain. 90 Retention of water on northern lakes zone and part of the northern floodplain As above As above 1.3 - 2.6 Frequency of inundation for vigour of lignum plants: around 20% cover 154,000 Volume associated with large-scale waterbird breeding 90 Time that it takes many waterbird species to fledge As above Waterbirds may continue breeding events across winter Twice in 8 years - twice in 10 years To provide at least two breeding opportunities during the life-cycle of a straw-necked ibis to protect and restore waterbird populations. 250,000 Habitat in all of open water lakes and much of the northern and central floodplains. 180 Required duration for water to move onto large areas of northern and central floodplain As above Summer dominated system, but will be largely an unregulated event so can happen any time 8 - 10 Critical period for survival of lignum in Narran Lakes (in small form and sparse) and other key vegetation species on northern and central floodplains Page 89
'Near to final' draft for independent review - 9 May 2016 Appendix E - Listed species, Narran Lakes Species Recognised in international agreement(s) (1) Environment Protection & Biodiversity Conservation Act 1999 (Cwlth) Fisheries Management Act 2004 (NSW) Threatened Species Conservation Act 1995 (NSW) Birds Australasian bittern (Botaurus poiciloptilus) E Bar-tailed godwit (Limosa lapponica) Yes Black-necked stork (Ephippiorhynchus asiaticus) E Black-tailed godwit (Limosa limosa) Yes V Blue-billed duck (Oxyura australis) V Brolga (Grus rubicundus) V Caspian tern (Sterna caspia)3 Yes Cattle egret (Ardea ibis) Yes Curlew sandpiper (Calidrus ferruginea)2 Yes Eastern great egret (Ardea modesta var. Ardea alba, Egretta alba) Yes Freckled duck (Stictonetta naevosa) V Glossy ibis (Plegadis falcinellus) Yes Greenshank (Tringa nebularia) Yes Latham’s snipe (Gallinago hardwickii) Yes Magpie goose (Anseranas semipalmata) V Marsh sandpiper (Tringa stagnatilis) Yes Sharp-tailed sandpiper (Calidrus acuminate) White-bellied sea-eagle (Haliaeetus leucogaster) Yes Fish Silver perch (Bidyanus bidyanus) CE V Olive perchlet (Ambassis agassizii) E (MDB population) E = endangered V = vulnerable CR = critically endangered, 1 Japan–Australia Migratory Bird Agreement, China–Australia Migratory Bird Agreement, or Republic of Korea – Australia Migratory Bird Agreement Page 106
'Near to final' draft for independent review - 9 May 2016 The site-specific flow indicators for the Narran Lakes UEA are in the table below. For each indicator, the flow indicator gauge is at Wilby Wilby on the Narran River. Site-specific flow indicator (SFI) Without development frequency SFI low uncertainty frequency SFI high uncertainty frequency Baseline frequency Maximum spell under without development Maximum spell under baseline 25,000 ML inflow volume over 60 days 0.7 years between an event (average) 1 year between an event (average) 1.3 years between an event (average) 1.3 years between an event (average) 3.2 years 7.5 years 50,000 ML inflow volume over 90 days 0.9 years between an event (average) 1.3 years between an event (average) 2.6 years between an event (average) 1.9 years between an event (average) 3.3 years 7.9 years 154,000 ML inflow volume over the first 90 days of the event 2 events in 79% of all 8 year periods; 2 events in 90% of all 10 year periods Twice in 8 years Twice in 10 years 2 events in 20% of all 8 year periods; 2 events in 27% of all 10 year periods N/A N/A 250,000 ML inflow volume over 180 days 6.5 years between an event (average) 10 years between an event (average) 12 years between an event (average) 16 years between an event (average) 30 years 55 years Page 108