US Army Corps of Engineers

Lower Granite Dam & Lake

August 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 2236 93 53 26.60 26.90 12.50 14.00 735.74 735.82 633.94 101.88 736.30
2 2350 98 53 25.90 27.20 13.00 13.60 735.43 735.57 633.82 101.75 735.87
3 2352 98 53 24.50 24.30 13.00 10.70 735.49 735.38 633.51 101.87 735.87
4 2290 95 53 27.60 27.10 12.70 13.90 735.62 735.61 633.84 101.77 736.01
5 2249 94 52 28.40 28.60 12.60 15.40 735.55 735.63 634.25 101.38 735.94
6 2231 93 51 29.70 29.70 12.50 16.70 735.55 735.57 634.06 101.51 735.92
7 2230 93 50 29.60 30.00 12.50 16.90 735.45 735.51 633.94 101.57 735.85
8 2237 93 53 27.00 27.50 12.50 14.40 735.30 735.33 633.81 101.52 735.72
9 2258 94 53 25.60 24.90 12.60 11.80 735.52 735.40 633.62 101.78 735.87
10 1340 56 52 26.60 26.10 10.00 15.60 735.63 735.70 633.51 102.19 736.03
11 1378 57 52 24.90 24.60 10.30 13.70 735.71 735.68 633.72 101.96 736.13
12 1476 62 52 26.00 25.90 10.70 14.70 735.73 735.70 633.88 101.82 736.17
13 1621 68 52 25.50 26.30 10.70 15.10 735.52 735.65 634.03 101.62 736.00
14 2145 89 51 25.50 26.10 12.10 13.40 735.37 735.45 634.26 101.19 735.79
15 2138 89 51 25.70 26.10 12.10 13.30 735.25 735.31 634.49 100.82 735.68
16 2164 90 51 25.10 23.30 12.30 10.70 735.72 735.40 634.95 100.45 736.06
17 2226 93 52 25.50 25.20 12.60 11.90 735.78 735.81 635.33 100.48 736.16
18 2277 95 51 26.10 25.60 12.90 12.10 735.89 735.84 635.98 99.86 736.28
19 2254 94 51 24.90 25.60 12.80 12.10 735.74 735.81 636.28 99.53 736.13
20 2248 94 52 24.60 25.20 12.80 11.90 735.61 735.64 635.96 99.68 735.96
21 2233 93 52 24.50 23.30 12.60 10.20 735.88 735.75 635.36 100.39 736.27
22 2232 93 52 24.60 25.20 12.60 12.10 735.74 735.78 635.65 100.13 736.15
23 2236 93 52 24.60 25.20 12.70 12.00 735.60 735.64 636.12 99.52 735.98
24 2215 92 52 23.30 23.30 12.70 10.10 735.59 735.61 636.37 99.24 735.96
25 2172 91 52 23.50 23.60 12.40 10.80 735.58 735.56 636.19 99.37 735.96
26 2209 92 52 22.40 23.00 12.60 9.90 735.42 735.50 635.66 99.84 735.81
27 2259 94 52 22.20 22.90 12.90 9.60 735.17 735.28 635.97 99.31 735.72
28 2246 94 52 21.90 21.50 12.80 8.00 735.31 735.28 636.14 99.14 735.74
29 2196 92 51 21.40 21.20 12.60 8.10 735.38 735.32 636.51 98.81 735.81
30 2182 91 52 21.20 21.20 12.50 8.10 735.39 735.37 636.27 99.10 735.76
31 2181 91 52 21.40 21.20 12.50 8.20 735.43 735.41 636.19 99.22 735.82
TOT 66061  1607         
AVG 2131 89 52 25.04 25.09 12.33 12.23 735.55 735.56 634.96 100.60 735.96
MAX 2352   29.70 30.00 13.00 16.90 735.89 735.84 636.51 102.19 736.30
MIN 1340   21.20 21.20 10.00 8.00 735.17 735.28 633.51 98.81 735.68
BUILDING STRONG®