Hydropower Plants in Iceland and Their Impact on Freshwater Fishes

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1 University of Massachusetts Amherst Amherst International Conference on Engineering and Ecohydrology for Fish Passage International Conference on Engineering and Ecohydrology for Fish Passage 2017 Jun 20th, 3:30 PM - 3:50 PM Hydropower Plants in Iceland and Their Impact on Freshwater Fishes Ingi Runar Jonsson Marine and Freshwater Research Institute Gudni Gudbergsson Marine and Freshwater Research Institute Sigurdur Gudjonsson Marine and Freshwater Research Institute Fridtjofur Arnason Marine and Freshwater Research Institute Follow this and additional works at: Jonsson, Ingi Runar; Gudbergsson, Gudni; Gudjonsson, Sigurdur; and Arnason, Fridtjofur, "Hydropower Plants in Iceland and Their Impact on Freshwater Fishes" (2017). International Conference on Engineering and Ecohydrology for Fish Passage This Event is brought to you for free and open access by the Fish Passage Community at UMass Amherst at ScholarWorks@UMass Amherst. It has been accepted for inclusion in International Conference on Engineering and Ecohydrology for Fish Passage by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact scholarworks@library.umass.edu.

2 Hydropower Plants in Iceland and Their Impact on Freshwater Fishes Ingi RunarJonsson, GudniGudbergsson, SigurdurGudjonsson and FridtjofurArnason Marine and Freshwater Research Institute Reykjavik, Iceland

3 Classification of rivers in Iceland Proportion of installed electrical capacity in hydropower plants 2015, by river origin. Numbers are numbers of power plants C C D C A D C 48 A B A B A. Spring-fed waters at the neovolcanic zone B. Direct run-off waters at the neovolcanic zone C. Short direct run-off waters of the Tertiary basalt formation D. Long direct run-off waters of the Tertiary basalt formation and waters originating from lakes or wetland heaths Gardarsson 1979 Gudjonsson Glacial origin Direct runoff or spring fed National Energy Authority 2015

4 Freshwater fish in Iceland Atlantic salmon (Salmo salar) Arctic charr (Salvelinus alpinus) Brown trout (Salmo trutta) Arctic charr Atlantic salmon Arctic charr Eel (Anguilla anguilla, Anguilla rostrata) Sticlebacks (Gaserosteus aculeatus) The dominant salmonid species in different parts of Iceland (Guðbergsson & Antonsson 1996)

5 River Blanda X Glacial river in North Iceland Stocks of Atlantic salmon, Arctic charr and brown trout Hydropower plant started operation in Reservoir enlarged in 1996 to 57 km 2. Veðurstofa Íslands 2012

6 River Blanda before the hydropower plant Glacial river flow pattern Flow unstable high during the summer (up to m 3 /s) low during the winter (down to 20 m 3 /s). Channel unstable. Fluctuating turbidity high during the summer lower during the winter. Silt on average t/year ( ) Low productivity Atlantic salmon and Arctic charr migratied to highland tributaries to spawn (500m a.s.l)

7 The impact of the Blönduvirkjun hydropower plant Canals through lakes => turbid The migration pathway to the highlands closed. Below power plant outlet Less fluctuating flow Less turbid water silt on average t/year ( ) Improved conditions for migratory fish (higher visibility) More stable channel Increased productivity Increased Atlantic salmon parr density Increased Atlantic salmon run/catch Higher value for fishing right owners and anglers Veðurstofa Íslands 2012

8 The impact of the Blönduvirkjun hydropower plant Between power plant outlet and dam Less flow (2-4 m3/s) No turbid water (except overflow) Stable channel Increased productivity Increased salmon parr density Increased salmon catch Number of salmon Veðurstofa Íslands 2012 Salmon catch in River Blanda between dam and power plant outflow

9 Kárahnjúkar hydropower plant X 2 4 S1 S2 S3 1. River Jökulsá á Dal dammed at Kárahnjúkar, creating Hálslón reservoir (63 km 2 ) 2. Water flow through tunnels to Fljótsdalsstöð power plant 3. Water through tunnels from Jökulsá á Fljótsdal og Kelduá watershed The outlet from the power plant to River Lagarfljót 5. The power plant started operation in 2007 S1, S2 and S3 ar sampling stations in Lake Lagarfljót

10 Lake Lagarfljót after hydropower plant Increased volumetric flow (less seasonal fluctuations) higher water level decreased lake retention time Increased turbidity due to increased inflow of glacial water with higher suspended solids Secchi depth (cm) 60 Station 1 50 Station 2 Station Year Secchi depth in Lake Lagarfljót Decreased mean water temperature (about C) Negative effect on productivity

11 Number of Arctic charr and brown trout caught in Lake Lagarfljót in one gill net series (10 60 mm) Number of charr Arctic charr Station 1 Station 2 Station 3 Number of trout Browntrout Station 1 Station 2 Station Year Year

12 Average length by age groups of Arctic charr and brown trout in Lagarfljót (station 1 and 2) before ( ) and after ( ) the Kárahnjúkar hydropower plant Length (cm) Age Arctic charr Length (cm) Age Brown trout Changes in stomach content of Arctic charr and brown trout - Increased proportion of food items of terrestrial origin

13 River Jökulsá á Dal Almost no fish production/catch in River Jökulsá á Dal before Hálslón reservoir. Primarily at the tributaries. Mostly Arctic charr, but also some salmon and brown trout. Release of salmon smolts in River Jökulsá and tributaries since 2006 Increasing salmon catch. Rod catch (number) Jökulsá á Dal Laxá Kaldá Rod catch of Atlantic salmon in River Jökulsá á Dal, River Laxá og River Kaldá Rod catch (number) Arctic charr Brown trout Rod catch of Arctic charr and brown trout in River Jökulsá á Dal, River Laxá og River Kaldá

14 River Jökulsá á Dal after the hydropower plant Less discharge (average 150 m 3 s m 3 s -1 ) Direct runoff river most part of the year overflow at Kárahnjúkar dam late summer Less suspended solids no silt while not flowing on overflow

15 River Jökulsá á Dal The overflow stopped before the spawning period. Wild and released Atlantic salmon parrs and smolts are found in River Jökulsá. The individual growth is high. Density of salmon parrs is still low. Large area. Increased Arctic charr stock size (searun charr?) The upper limits of the angling pools moving higher upstream each year. Some migration obstacles exists.

16 Conclusions Impact of hydropower plants on fish can be caused by several factors. As change in turbidity, discharge, migratory obstacles, channels change etc. Discharge and turbidity affecting fishing conditions. Affecting utilization of fish stocks. Time of year and duration of overflow is important factor.

17 Acknowledgements Collegues at the Institute of Freshwater Fisheries Fishing right owners and anglers Landsvirkjun, National Power Company of Iceland Thank you