US Army Corps of Engineers

John Day & Lake Umatilla

September 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 13100 546 41 97.70 87.80 71.60 15.00 263.62 263.28 160.44 102.84
2 14871 620 41 101.70 86.50 80.50 4.80 264.21 264.12 160.47 103.65
3 15236 635 42 95.70 85.20 82.40 1.60 264.62 264.44 160.90 103.54
4 16333 681 41 91.00 91.00 88.20 1.60 264.62 264.75 160.96 103.79
5 12890 537 40 71.90 71.90 69.10 1.60 264.62 264.60 160.39 104.21
6 12410 517 40 79.40 68.90 66.10 1.60 265.02 264.97 160.30 104.67
7 11626 484 40 67.50 65.00 62.10 1.60 265.12 265.02 160.60 104.42
8 13379 557 38 79.40 74.20 71.50 1.60 265.32 265.26 160.66 104.60
9 13540 564 35 72.70 75.40 72.40 1.60 265.22 265.15 160.62 104.53
10 14074 586 36 83.30 78.10 75.40 1.60 265.42 265.37 160.66 104.71
11 12136 506 35 72.70 67.40 64.60 1.60 265.62 265.58 160.24 105.34
12 12574 524 34 66.80 69.40 66.80 1.60 265.52 265.51 160.33 105.18
13 12655 527 34 57.10 70.10 67.20 1.60 265.02 265.22 160.16 105.06
14 12035 501 35 59.00 66.90 64.00 1.80 264.72 264.92 159.98 104.94
15 69.20 68.80 65.90 1.60 264.82 264.83 159.81 105.02
16 70.30 67.70 64.90 1.60 264.92 265.11 159.80 105.31
17 59.70 67.40 64.60 1.60 264.82 264.98 160.24 104.74
18 75.20 67.40 64.60 1.60 265.12 265.14 160.36 104.78
19 75.50 70.30 67.50 1.60 265.32 265.27 160.40 104.87
20 70.40 70.40 67.40 1.60 265.32 265.31 160.10 105.21
21 69.60 69.60 66.70 1.60 265.32 265.34 159.96 105.38
22
23
24
25
26
27
28
29
30
TOT186859  531        
AVG 13347 556 38 75.51 73.30 69.69 2.40 264.97 264.96 160.35 104.61
MAX 16333   101.70 91.00 88.20 15.00 265.62 265.58 160.96 105.38
MIN 11626   57.10 65.00 62.10 1.60 263.62 263.28 159.80 102.84
BUILDING STRONG®