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 2133 89 47 66.50 66.80 12.00 54.20 735.09 734.95 633.44 101.51 735.38
7 2140 89 47 65.00 64.90 12.00 52.40 735.11 734.97 633.27 101.70 735.51
8 2156 90 47 64.80 63.80 12.00 51.20 735.44 735.21 633.37 101.84 735.83
9 2144 89 46 65.60 65.60 12.00 53.20 735.44 735.50 633.68 101.82 735.85
10 2132 89 46 64.80 66.20 12.00 53.80 735.06 735.25 633.81 101.44 735.55
11 2146 89 46 64.90 63.80 12.00 51.30 735.34 735.19 633.82 101.37 735.79
12 2173 91 46 70.30 70.70 12.20 58.10 735.21 735.16 634.09 101.07 735.73
13 2150 90 42 76.10 76.30 12.10 63.70 735.14 734.94 634.09 100.85 735.66
14 2169 90 47 78.40 78.70 12.20 66.00 735.10 735.05 634.31 100.74 735.60
15 2194 91 47 76.00 76.10 12.30 63.30 735.11 735.10 634.28 100.82 735.69
16 2197 92 48 81.20 80.80 12.40 68.00 735.25 735.25 634.40 100.85 736.05
17 2198 92 48 78.60 77.30 12.30 64.60 735.59 735.37 633.81 101.56 736.25
18 2192 91 48 73.90 73.40 12.20 60.60 735.69 735.56 633.64 101.92 736.33
19 2200 92 47 68.70 69.50 12.20 56.70 735.52 735.51 633.51 102.00 736.13
20 2197 92 47 67.20 68.60 12.30 55.80 735.11 735.23 633.56 101.67 735.74
21 2195 91 47 68.90 70.80 12.30 58.00 734.73 734.95 633.73 101.22 735.69
22 2143 89 48 76.70 74.30 12.00 61.70 735.27 734.92 633.65 101.27 736.01
23 2327 97 47 91.20 92.50 13.10 78.90 734.97 735.01 634.03 100.98 735.87
24 2184 91 48 90.70 92.70 12.30 80.00 734.50 734.72 634.10 100.62 735.52
25 2146 89 47 86.50 85.80 12.10 73.20 734.67 734.59 633.67 100.92 735.46
26 2164 90 47 84.10 81.60 12.10 69.10 735.26 735.06 633.40 101.66 736.06
27 2164 90 47 81.60 80.80 12.10 68.20 735.47 735.06 633.59 101.47 736.13
28 2193 91 47 75.90 75.90 12.20 63.30 735.48 735.57 633.59 101.98 736.18
29 2158 90 46 74.50 74.80 12.00 62.30 735.38 735.37 633.35 102.02 736.06
30 2181 91 46 72.10 72.50 12.10 60.00 735.26 735.27 633.15 102.12 735.91
TOT 81443  1402         
AVG 2715 113 47 73.78 73.72 15.28 57.97 735.21 735.14 633.75 101.40 735.81
MAX 10521   91.20 92.70 60.00 80.00 735.69 735.57 634.40 102.12 736.33
MIN 2127   64.80 63.80 12.00 7.90 734.50 734.59 633.15 100.62 735.38
BUILDING STRONG®