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
24 180.60 184.10 180.10 0.00 339.57 339.59 266.59 73.00
25 183.10 184.70 180.70 0.00 339.45 339.51 266.63 72.88
26 185.20 186.10 182.10 0.00 339.48 339.36 266.64 72.72
27 183.20 186.20 182.20 0.00 339.32 339.47 266.78 72.69
28 204.80 198.10 182.00 12.10 339.58 339.66 266.89 72.77
29 181.90 190.90 180.60 6.30 339.17 339.45 266.85 72.60
30 190.40 187.60 183.60 0.00 339.24 339.13 266.89 72.24
31
TOT422102  2760        
AVG 18352 765 120 161.80 161.53 153.17 3.99 338.72 338.72 266.30 72.42
MAX 22876   204.80 198.30 183.60 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®