Fishways: Restoring Coastal Aquatic Connectivity. Matt Moore

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1 Fishways: Restoring Coastal Aquatic Connectivity Matt Moore

2 Barriers to Fish Passage Barrier Passability Importance of Maintaining Fish Connectivity Overview Fish Physiology, Biology, Migration & Swimming Modes Identifying Restoration Sites Fish Barrier Prioritisation Restoring Aquatic Connectivity Nature-like Rock Ramp Fishways Concrete Cone Fishways Culvert Fishways Horizontal & Vertical Baffle + V-Slot Fish Passage Restoration Examples Bremer River Rock Ramp Fishway Slacks Creek Rock Ramp Fishway Monitoring Boundary Ck Fishway Fishways & Wetland Restoration

3 Fish Barrier Types: Box & Pipe Culverts Road Crossings Bunds & Sand Dams Ponded Pastures Dams & Weirs Floodgates Tidal Drop Board Structures Weed Choke Hymenachne & Para Grass Water Quality DO Fish Barrier Characteristics Water surface drop Velocity &Turbulence Shallow Water Surface Water Quality Barriers to Fish Passage

4 Barrier Passability How often is fish passage available? Low Passability Rarely drowns out 1 or less flow event per yr Dams & Large weirs ( 2 m headloss) Aplins, Caboolture, Mt Crosby & Luscombe Weirs Medium Passability Occasionally drowns out ~2-8 times per yr Causeway <2m (headloss) Pipe/culvert <60% bankfull width High Passability Frequently drowns out Pipe/culvert >60% bankfull width Causeway <0.3 m What do fish do if they can t migrate past the barrier? Small windows of opportunity Jungle perch

5 Why Is Fish Passage & Connectivity Important Fish Migration Life-Cycle Dependant (Diadromous) Long & Short-fin Eels, Sea & Freshwater Mullet, Jungle Perch, Tarpon Empire Gudgeon, Mangrove Jack Barramundi Juveniles and small bodied fish = Upstream Migration Wholly Freshwater Species (Potamodromous) Rainbowfish, Eel-tail Catfish Commercial Recreational Indigenous Environmental/Social Apex Predators Pest Control Vicarious Values Waterway Health Transfer of energy

6 Fish Physiology & Biology Why Is Fish Passage & Connectivity Important Secondary Freshwater Fish Recently evolved from marine ancestors Poor swimmers Poor leaping ability Utilise king tides & wet season flows Northern Hemisphere fish sp. i.e. Atlantic Salmon Great swimmers + can jump Aust. predominantly juvenile & small bodied species low-median flows Large bodied sp.@ elevated/drown out flows Swimming Modes Burst Speed - 15 seconds - Must have time to recover before next burst. Sustained Speed - 16 sec - 20 mins -Long periods Prolonged Speed min Velocity through culverts = 0.4 m/sec

7 Identifying Restoration Sites - Fish Barrier Prioritisation Fish Barrier Priorisation Process ID potential barriers via Aerial Imagery Thousands of barriers SEQ Barrier Prioritisation -ID 13,797 potential barriers Mackay/Whitsunday = 3,974 3 stage prioritisation process Stage 1 Desktop analysis Utilise GIS stream network analysis tools to priority rank into manageable list Stream Hierarchy, Landuse (% intensive) No. Barriers downstream, Distance to the next barrier upstream location within the catchment (% catchment blocked U/S) Ground-truth most important 1st

8 Identifying Restoration Sites - Fish Barrier Prioritisation Cont. Stage 2 Barrier Type + Ecological Criteria Barrier Type Tidal barrage/culverts etc. Stream/Riparian Condition % disturbance Flow Condition Perennial/seasonal In-stream Habitat/Refuge Proximity to Estuary Stage 3 Social, Economic Cost to remediate Community support Technicality of remediation option Improved productivity from remediation Important conservation species present Barrier Passability End result top ~150 barriers to fish passage Guide restoration funds towards remediating the most important barriers 1 st - Bang for Buck

9 Restoring Connectivity = Nature-like Rock Ramp Fishways Pros: Natural appearance Cheap/Cost effective Proven results Great for juvenile diadromous/small bodied species/poor swimmers Roughened so produce micro habitats assisting juvenile fish Barriers up to 3 4 m? Cons: Difficult to obtain precise control height Control volume of water through slots Require sufficient room Proximity to Rock Supply

10 Restoring Connectivity = Concrete Cone Fishways Pros: Proven results Exact drops between ridges Don t require close proximity to rock supply Don t require as much space Cons: Engineered/concrete appearance potentially looks out of place in a waterway? Cost higher cost than R.Ramps Concrete cones are pre-cast offsite, so require crane access to lower them in place

11 Culvert Fishways - Horizontal & Vertical Baffle Horizontal Concrete Baffles New innovative design Boxed up + poured in-situ 60 mm drops High flow & low flow slots Angled D/S slot chamfer Resting areas Convey stream flows Turbulence dissipation Vertical Baffles Galvanised C-section purlin + bolted Stream flow conveyance Cheaper Rust - material depend No resting pools Damaged by logs

12 Fish Passage Restoration Examples Bremer River Nature-like Rock Ramp Fishway Brisbane R Catchment Weir 1960 s 2.4 m high (headloss) Priority Ranked 7th in SEQ Longest Rock Ramp f/way in Australia - 90 m long Dog-leg fishway 33 pools and ridges Deep pools - ~500 mm Turbulence dissipation 450 t large rock m 32 m fibre reinforced concrete 3 wks construction Low Cost

13 Fish Passage Restoration Examples Monitoring - Bremer River Nature-like Rock Ramp Fishway Instant success Monitoring = Ave 690 fish/day 21 species 4 new sp. for Bremer 34 mm median size 32% diadromous 99.94% native PIT Tagged juvenile Bass & endangered Mary River Cod - successful at ascending Juvenile and small bodied fish on small flows Adult & larger bodied fish high flows

14 Fish Passage Restoration Examples Slacks Creek nature-like Rock Ramp & Horizontal Baffle Fishway Logan River Catchment Ranked 36 th highest barrier in SEQ 1.8 m high (headloss) barrier 1.3 m vertical apron drop off culvert apron 0.5 m cross fall through culverts 50 m long culverts 17 ridge nature-like rock ramp 750 t rock 20 m3 fibre reinforced 10 Horizontal concrete culvert baffles invert 60 mm drops 3wks

15 Measuring Success: Boundary Ck Concrete Cone Fishway Monitoring Rocky Dam Creek Catchment, Koumala Ranked 13 th highest barrier in MW 2016 Ave 1109 fish/day 11 sp. - 73% diadromous Indonesian goby, Greenback mullet, Crescent perch, Threadfin silver-biddy, Giant Herring, 43 mm Barramundi top of f/way, 18 mm halfway 1096 banded scats & 283 threadfin silver-biddy s in 6.5 hrs

16 Lagoons Ck Wetland Restoration Fishways & Wetland Restoration Cane Drain + Para Grass Mackay Botanic Gardens 5 Rock Ramp Fishways 2 constructed wetlands Fishway Monitoring 2016 = 3160 fish/day 2017 = 453 fish/day 14 sp.