US Army Corps of Engineers

John Day & Lake Umatilla

May 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 11617 484 44 242.60 240.00 62.60 176.00 265.22 265.13 161.08 104.05
2 11511 480 44 236.00 228.20 61.60 165.30 265.52 265.36 160.70 104.66
3 11461 478 43 245.80 240.60 61.40 177.90 265.72 265.66 160.99 104.67
4 11427 476 46 223.80 236.90 61.40 174.20 265.22 265.50 161.29 104.21
5 11921 497 47 250.00 252.60 64.30 187.10 265.12 265.30 161.36 103.94
6 11393 475 46 228.00 222.80 61.60 160.10 265.32 265.15 161.39 103.76
7 11462 478 47 237.90 224.90 61.90 161.80 265.82 265.64 161.88 103.76
8 11403 475 46 223.30 225.90 61.40 163.10 265.72 265.71 161.53 104.18
9 11244 469 46 230.70 235.90 60.40 174.20 265.52 265.69 161.23 104.46
10 11184 466 45 257.80 250.00 60.00 188.60 265.82 265.47 160.98 104.49
11 11203 467 46 241.20 249.00 60.40 187.40 265.52 265.54 161.50 104.04
12 11110 463 45 240.30 242.90 59.80 181.90 265.42 265.46 161.29 104.17
13 11126 464 45 240.90 238.30 60.00 177.10 265.52 265.23 161.18 104.05
14 11185 466 46 241.40 241.40 60.20 179.90 265.52 265.53 161.37 104.16
15 11184 466 46 260.30 257.60 60.40 195.80 265.62 265.54 161.71 103.83
16 11288 470 45 236.30 241.50 61.00 179.40 265.42 265.36 161.54 103.82
17 11386 474 45 234.40 234.40 61.40 171.50 265.42 265.54 161.49 104.05
18 11562 482 44 233.00 235.60 62.10 172.20 265.32 265.33 160.97 104.36
19 11385 474 44 219.30 219.30 61.20 156.90 265.32 265.24 160.99 104.25
20 11337 472 43 216.80 212.50 61.10 149.90 265.32 265.25 161.22 104.03
21 4722 197 16 211.70 211.70 60.40 150.00 265.52 265.52 161.22 104.30
22 11297 471 42 198.20 211.20 60.30 149.90 265.02 265.29 161.13 104.16
23 11337 472 42 183.90 183.90 60.30 122.30 265.02 264.97 160.52 104.45
24 11301 471 42 185.80 180.60 60.30 119.10 265.22 265.14 160.85 104.29
25 11174 466 42 196.00 188.20 59.60 127.40 265.52 265.24 161.04 104.20
26 10777 449 43 194.10 191.50 57.50 132.70 265.62 265.53 161.16 104.37
27 10811 450 42 215.20 212.60 57.40 153.90 265.72 265.67 160.97 104.70
28 11201 467 42 219.20 227.00 59.90 165.90 265.52 265.52 161.48 104.04
29 213.70 203.20 59.70 142.10 265.82 265.25 160.91 104.34
30 211.10 213.70 59.40 153.00 265.72 265.90 161.52 104.38
31 208.50 232.00 60.10 170.80 264.82 265.21 161.76 103.45
TOT310009  1216        
AVG 11072 461 43 225.07 225.35 60.62 163.46 265.45 265.42 161.23 104.18
MAX 11921   260.30 257.60 64.30 195.80 265.82 265.90 161.88 104.70
MIN 4722   183.90 180.60 57.40 119.10 264.82 264.97 160.52 103.45
BUILDING STRONG®