US Army Corps of Engineers

McNary Dam & Lake Wallula

September 2025

Day of MonthTotal Generation MWhAverage Generation MWStation Use MWhInflow kcfsTotal Outflow kcfsGeneration Flow kcfsSpill kcfsMidnight Reservoir ElevationAverage Forebay ElevationAverage Tailwater ElevationAverage Head feet
1 14176 591 96 111.00 116.40 109.80 1.90 338.84 339.21 265.55 73.66
2 13408 559 96 118.20 111.60 105.10 1.80 339.23 339.24 266.29 72.95
3 11355 473 96 89.50 95.00 88.50 1.80 338.94 339.29 266.30 72.99
4 10082 420 96 82.30 84.90 78.40 1.80 338.78 339.17 266.14 73.03
5 10349 431 96 97.00 86.40 79.80 1.80 339.37 339.30 266.05 73.25
6 8486 354 96 64.20 71.70 65.20 1.80 338.99 339.21 265.72 73.49
7 7718 322 96 60.40 65.90 59.50 1.70 338.68 338.81 265.59 73.22
8 7468 311 96 61.00 64.00 57.60 1.60 338.48 338.52 265.40 73.12
9 7515 313 96 76.80 64.20 57.90 1.60 339.15 338.69 265.32 73.37
10 8149 340 96 68.70 68.90 62.40 1.80 339.11 339.24 265.37 73.87
11 8835 368 96 74.70 74.50 68.10 1.70 339.16 339.28 265.62 73.66
12 9023 376 96 75.30 75.60 69.20 1.80 339.11 339.38 265.57 73.81
13 9113 380 96 73.90 76.60 70.10 1.80 339.01 339.30 265.60 73.70
14 7841 327 96 66.80 67.00 60.60 1.70 338.99 338.96 265.60 73.36
15 7361 307 96 61.40 62.80 56.40 1.70 338.90 338.86 265.14 73.72
16 8919 372 96 74.20 75.00 68.60 1.70 338.83 338.93 265.19 73.74
17 11774 491 96 92.70 95.50 89.10 1.70 338.71 338.87 265.56 73.31
18 12673 528 96 106.70 101.90 95.50 1.70 338.97 338.99 265.73 73.26
19 12809 534 96 104.10 104.50 98.10 1.70 338.94 338.90 266.10 72.80
20 10853 452 96 99.40 90.90 84.40 1.80 339.40 339.35 265.94 73.41
21 9033 376 96 74.20 76.00 69.40 1.80 339.31 339.41 265.85 73.56
22 8464 353 96 56.30 72.10 65.70 1.70 338.46 338.89 265.66 73.23
23 8005 334 96 76.40 68.20 61.90 1.70 338.92 338.82 265.47 73.35
24 8728 364 109 73.80 73.10 66.60 1.80 338.88 339.17 265.42 73.75
25 8897 371 120 82.00 75.20 68.70 1.70 339.24 339.24 265.73 73.51
26 7199 300 120 59.20 61.60 55.10 1.70 339.10 339.13 265.49 73.64
27 7199 300 120 57.50 61.40 55.00 1.70 338.91 339.06 265.31 73.75
28 7231 301 120 68.50 61.50 55.10 1.70 339.31 339.07 265.11 73.96
29 7813 326 120 65.30 65.80 59.30 1.80 339.22 339.41 265.11 74.30
30 7692 320 120 68.60 64.70 58.20 1.80 339.44 339.43 264.97 74.46
TOT278166  3037        
AVG 9272 386 101 78.00 77.76 71.31 1.74 339.01 339.10 265.60 73.51
MAX 14176   118.20 116.40 109.80 1.90 339.44 339.43 266.30 74.46
MIN 7199   56.30 61.40 55.00 1.60 338.46 338.52 264.97 72.80
BUILDING STRONG®