US Army Corps of Engineers

McNary Dam & Lake Wallula

December 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 15363 640 120 130.50 123.80 119.10 0.00 339.21 339.26 265.24 74.02
2 15452 644 120 109.70 125.40 120.70 0.00 338.42 338.89 265.53 73.36
3 15172 632 120 114.70 125.40 120.70 0.00 337.80 338.21 265.86 72.35
4 14109 588 120 119.80 116.70 112.00 0.00 337.96 337.92 265.61 72.31
5 15698 654 120 126.90 130.00 125.30 0.00 337.82 337.92 265.81 72.11
6 15806 659 120 142.20 129.50 124.80 0.00 338.46 338.23 265.74 72.49
7 16016 667 120 131.60 129.70 125.00 0.00 338.63 338.62 265.34 73.28
8 16091 670 120 131.90 129.50 124.80 0.00 338.72 338.57 265.24 73.33
9 15822 659 120 125.70 127.00 122.30 0.00 338.65 338.88 265.40 73.48
10 18504 771 120 138.10 151.80 147.10 0.00 337.93 338.44 266.27 72.17
11 18009 750 120 138.20 150.60 145.90 0.00 337.24 337.60 266.37 71.23
12 19551 815 120 166.20 161.40 156.70 0.00 337.54 337.29 266.94 70.35
13 20467 853 120 173.10 165.30 160.60 0.00 337.94 337.77 267.28 70.49
14 20754 865 120 159.50 162.20 157.50 0.00 337.77 337.91 267.57 70.34
15 17947 748 120 148.70 143.40 138.70 0.00 338.11 337.93 267.05 70.88
16 17732 739 120 146.50 151.90 139.10 8.40 337.80 337.84 266.58 71.26
17 17205 717 120 179.50 163.30 138.50 20.70 338.71 337.85 266.71 71.14
18 18714 780 120 201.40 189.50 149.00 36.50 339.22 338.95 266.31 72.64
19 22328 930 120 198.50 190.60 176.90 9.70 339.81 339.25 266.35 72.90
20 22859 952 120 172.50 186.90 180.20 2.70 338.96 339.34 266.07 73.27
21 22876 953 120 203.00 188.20 179.80 4.50 339.76 339.38 265.92 73.46
22 22798 950 120 195.20 198.30 179.70 14.60 339.53 339.56 266.27 73.29
23 22830 951 120 191.50 187.70 179.50 4.20 339.83 339.68 266.24 73.44
24 22756 948 120 180.60 184.10 180.10 0.00 339.57 339.59 266.59 73.00
25 22761 948 120 183.10 184.70 180.70 0.00 339.45 339.51 266.63 72.88
26 22875 953 120 185.20 186.10 182.10 0.00 339.48 339.36 266.64 72.72
27 22879 953 120 183.20 186.20 182.20 0.00 339.32 339.47 266.78 72.69
28 22875 953 120 204.80 198.10 182.00 12.10 339.58 339.66 266.89 72.77
29 22637 943 120 181.90 190.90 180.60 6.30 339.17 339.45 266.85 72.60
30 22874 953 120 190.40 187.60 183.60 0.00 339.24 339.13 266.89 72.24
31 22905 954 120 186.50 187.90 183.90 0.00 339.26 339.30 267.08 72.22
TOT604664  3720        
AVG 19505 813 120 162.60 162.38 154.16 3.86 338.74 338.73 266.32 72.41
MAX 22905   204.80 198.30 183.90 36.50 339.83 339.68 267.57 74.02
MIN 14109   109.70 116.70 112.00 0.00 337.24 337.29 265.24 70.34
BUILDING STRONG®