US Army Corps of Engineers

Lower Granite Dam & Lake

April 2026

Day of MonthTotal Generation MWhAverage Generation MWStation Use MWhInflow kcfsTotal Outflow kcfsGeneration Flow kcfsSpill kcfsMidnight Reservoir ElevationAverage Forebay ElevationAverage Tailwater ElevationAverage Head feetMidnight Lewiston Gage ft
1 9909 413 45 66.50 64.90 56.60 7.90 735.12 735.18 634.19 100.99 735.63
2 10521 438 47 68.90 68.50 60.00 7.90 735.30 735.12 633.98 101.14 735.81
3 2295 96 47 74.00 74.20 12.80 60.90 735.21 735.19 633.55 101.64 735.69
4 2212 92 48 71.60 71.80 12.40 59.00 735.14 735.09 633.72 101.37 735.60
5 2127 89 47 68.20 68.00 12.00 55.70 735.20 734.96 633.62 101.34 735.46
6 66.50 66.80 12.00 54.20 735.09 734.95 633.44 101.51 735.38
7 65.00 64.90 12.00 52.40 735.11 734.97 633.27 101.70 735.51
8 64.80 63.80 12.00 51.20 735.44 735.21 633.37 101.84 735.83
9 65.60 65.60 12.00 53.20 735.44 735.50 633.68 101.82 735.85
10 64.80 66.20 12.00 53.80 735.06 735.25 633.81 101.44 735.55
11 64.90 63.80 12.00 51.30 735.34 735.19 633.82 101.37 735.79
12 70.30 70.70 12.20 58.10 735.21 735.16 634.09 101.07 735.73
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TOT 27066  234         
AVG 5413 226 47 67.59 67.43 19.83 47.13 735.22 735.15 633.71 101.44 735.65
MAX 10521   74.00 74.20 60.00 60.90 735.44 735.50 634.19 101.84 735.85
MIN 2127   64.80 63.80 12.00 7.90 735.06 734.95 633.27 100.99 735.38