Table 1: The Krahnjkar hydro scheme in figures

Source: Landsvirkjun

Installed capacity 690MW
Generating capacity Approx. 4,600GWh/year
Turbines Francis, vertical axis
– Number 6
– Rated discharge per unit 24m3/sec
– Rated output per unit 115MW
Total head 599m
Rated discharge (maximum discharge) 144m3/sec
Average discharge 110m3/sec
Hlsln reservoir
– Area of full reservoir 57km2
– Length of reservoir 25km
– Live storage 2,100Mm3
– Reservoir full supply level (FSL) 625m asl
– Reservoir minimum operating level (MOL) 575m asl
– Hlsln reservoir catchment area 1806km2
– Average inflow to Hlsln reservoir 107m3/sec
Krahnjkastfla dam
– Maximum dam height 193m
– Dam length 730m
– Fill materials 8.5Mm3
Desjarrstfla dam
– Maximum dam height 60m
– Dam length 1100m
– Fill materials 2.8Mm3
Sau_rdalsstfla dam
– Maximum dam height 25m
– Dam length 1.100m
– Fill materials 1.5Mm3
Ufsarln pond
– Area of full reservoir 1km2
– Maximum water level 625m asl.
– Ufsarln pond catchment area 430km2
– Average inflow to Ufsarln pond 31m3/sec
Ufsarstfla dam
-Maximum dam height 37m
– Dam length 620m
– Fill materials 0.6Mm3
Keldurln reservoir
– Area of full reservoir 7.5km2
– Reservoir full supply level (FSL) 669m asl
– Live storage 60Mm3
Keldurstfla dam
– Maximum dam height 26m
– Dam length 1,650m
– Fill materials 0.8Mm3
Tunnels Approx. 72km
Headrace from Hlsln (dia: 7.2-7.6 m) 39.7km
Headrace from Ufsarln (dia: 6.5 m) 13.3km
3 adits to headrace (dia: 7.2-7.6 m) 6.9km
2 diversion tunnels and adit at dam 2,4km
Grouting galleries at dam 0.5km
Surge tunnel (dia: 4.5 m) 1.7km
2 diversion tunnels Hraunaveita (dia: 4.5 m) 3.7km
2 vertical pressure tunnels (dia: 4.0 m) 0.8km
Access tunnel to power station (dia: 7.5 m) 1km
Tailrace tunnel (dia: 9.0 m) 1.3km
Cable tunnel (dia: 4.0 m) 1km