US Army Corps of Engineers

McNary Dam & Lake Wallula

October 2026

Day of MonthTotal Generation MWhAverage Generation MWStation Use MWhInflow kcfsTotal Outflow kcfsGeneration Flow kcfsSpill kcfsMidnight Reservoir ElevationAverage Forebay ElevationAverage Tailwater ElevationAverage Head feet
1 8429 351 120 70.10 74.20 65.80 3.60 338.66 338.85 265.77 73.08
2 7729 322 120 69.50 66.20 59.90 1.70 338.87 338.88 265.44 73.44
3 8676 362 120 74.40 73.90 67.30 1.80 338.87 339.09 265.58 73.51
4 8897 371 120 73.20 76.00 69.60 1.70 338.74 339.02 265.81 73.21
5 8404 350 120 69.20 72.00 65.70 1.60 338.58 338.74 265.65 73.09
6 9429 393 120 83.40 79.20 72.80 1.70 338.82 338.74 265.59 73.15
7 10856 452 120 97.90 94.70 82.20 7.80 338.98 338.93 265.94 72.99
8 10646 444 120 95.40 103.20 81.30 17.20 338.54 338.86 266.24 72.62
9 7440 310 120 91.50 81.20 57.40 19.10 339.08 339.04 265.88 73.16
10 6973 291 120 69.90 72.90 53.60 14.60 338.95 339.02 265.55 73.47
11 8120 338 120 75.20 70.60 62.20 3.60 339.18 339.15 265.27 73.88
12 8227 343 120 77.00 72.60 62.70 5.20 339.46 339.34 265.17 74.17
13 9817 409 120 85.50 85.40 75.50 5.20 339.46 339.43 265.46 73.97
14 8829 368 120 78.70 80.50 67.70 8.20 339.33 339.47 265.75 73.72
15 8068 336 120 70.50 73.90 61.90 7.30 339.17 339.49 265.64 73.85
16 8200 342 120 66.10 70.20 63.80 1.70 338.97 339.05 265.73 73.32
17 7138 297 120 59.40 61.60 55.20 1.70 338.85 338.89 265.53 73.36
18 6620 276 120 57.60 57.90 51.50 1.70 338.83 338.89 265.37 73.52
19 7208 300 120 60.10 61.90 55.70 1.50 338.72 338.76 265.26 73.50
20 8209 342 120 76.50 69.80 63.40 1.70 339.09 339.09 265.37 73.72
21 8879 370 120 84.10 78.70 68.60 5.40 339.40 339.34 265.70 73.64
22 7674 320 120 72.00 71.90 59.00 8.20 339.40 339.46 265.72 73.74
23 7557 315 120 72.80 66.70 58.20 3.80 339.69 339.55 265.91 73.64
24 8207 342 120 62.00 69.70 63.20 1.80 339.31 339.47 265.90 73.57
25 7875 328 120 62.40 67.50 61.10 1.80 339.00 339.21 265.94 73.27
26 7581 316 120 67.00 65.20 58.80 1.70 339.14 339.13 265.97 73.16
27 8516 355 120 75.70 72.40 66.00 1.70 339.27 339.36 266.16 73.20
28 9610 400 120 67.90 85.20 75.60 4.90 338.37 338.87 266.34 72.53
29 8853 369 120 72.50 75.80 69.50 1.60 338.19 338.36 266.06 72.30
30 84.00 77.00 70.60 1.70 338.57 338.49 266.05 72.44
31 90.40 87.60 75.10 7.70 338.72 338.84 266.22 72.62
1 84.00 84.00 62.20 17.10 338.76 338.96 266.07 72.89
TOT242668  3480        
AVG 8368 349 120 74.87 74.99 65.10 5.19 338.97 339.06 265.75 73.30
MAX 10856   97.90 103.20 82.20 19.10 339.69 339.55 266.34 74.17
MIN 6620   57.60 57.90 51.50 1.50 338.19 338.36 265.17 72.30
BUILDING STRONG®