US Army Corps of Engineers

Lower Granite Dam & Lake

May 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 2222 93 46 69.60 70.10 12.40 57.30 735.10 735.02 633.23 101.79 735.69
2 2158 90 46 68.20 69.20 12.10 56.70 734.91 734.91 633.24 101.67 735.55
3 2156 90 46 66.40 65.90 12.10 53.40 735.00 735.03 633.36 101.67 735.70
4 2168 90 46 68.50 67.60 12.10 55.00 735.19 734.94 633.50 101.44 735.78
5 2218 92 45 75.30 75.50 12.40 62.50 735.14 735.02 633.81 101.21 735.84
6 2142 89 46 78.80 79.60 12.10 67.00 734.96 734.91 633.90 101.01 735.66
7 2151 90 46 82.00 81.40 12.10 68.80 735.08 734.98 634.01 100.97 735.85
8 2147 89 46 87.60 87.00 12.10 74.50 735.23 735.18 634.33 100.85 736.12
9 2150 90 45 87.90 88.30 12.10 75.60 735.13 735.07 633.92 101.15 735.93
10 2144 89 46 87.10 86.90 12.00 74.40 735.22 735.06 633.71 101.35 736.06
11 2152 90 45 87.80 88.40 12.10 75.90 735.06 735.02 633.74 101.28 735.89
12 2148 90 45 89.70 90.30 12.10 77.60 734.93 735.02 633.75 101.27 735.83
13 2558 107 45 95.80 95.40 14.40 80.50 735.00 734.99 634.09 100.90 735.99
14 3654 152 45 101.00 103.30 20.70 82.20 734.49 735.04 634.42 100.62 735.72
15 2300 96 45 98.00 97.10 13.00 83.70 734.71 734.64 634.13 100.51 735.74
16 2139 89 46 90.90 89.10 12.10 76.40 735.08 734.73 634.11 100.62 735.83
17 2160 90 46 81.70 83.20 12.20 70.60 734.77 734.91 633.70 101.21 735.67
18 2156 90 46 77.10 76.00 12.10 63.40 734.98 734.71 633.29 101.42 735.51
19 2159 90 46 72.30 71.30 12.10 58.60 735.29 735.10 633.31 101.79 735.90
20 2188 91 46 63.90 64.10 12.20 51.40 735.23 735.17 633.38 101.79 735.86
21 2198 92 45 59.20 59.60 12.30 46.90 735.10 735.06 633.55 101.51 735.66
22 2195 91 46 54.90 54.50 12.30 41.70 735.22 735.06 633.50 101.56 735.66
23 2202 92 45 54.60 53.90 12.30 41.10 735.42 735.29 633.47 101.82 735.95
24 2200 92 45 55.50 54.70 12.30 42.10 735.64 735.46 633.48 101.98 736.18
25 2186 91 45 58.40 57.40 12.20 44.70 735.88 735.68 633.52 102.16 736.63
26 2182 91 46 63.60 64.10 12.20 51.30 735.77 735.81 633.82 101.99 736.39
27 2185 91 45 67.50 67.80 735.69 735.61 633.80 101.81 736.41
28 2180 91 47 72.50 73.30 735.50 735.66 634.10 101.56 736.30
29 78.30 78.40 735.48 735.38 634.23 101.15 736.30
30 75.90 76.90 12.20 64.20 735.20 735.15 634.40 100.75 735.82
31 71.90 71.50 12.10 59.00 735.31 735.29 634.13 101.16 735.97
TOT 62798  1277         
AVG 2243 93 46 75.55 75.54 12.59 62.73 735.18 735.13 633.77 101.35 735.92
MAX 3654   101.00 103.30 20.70 83.70 735.88 735.81 634.42 102.16 736.63
MIN 2139   54.60 53.90 12.00 41.10 734.49 734.64 633.23 100.51 735.51
BUILDING STRONG®