Bonneville Dam & Lake on Columbia River

April 2026

Day of Month	Total Generation MWh	Average Generation MW	Station Use MWh	Inflow kcfs	Total Outflow kcfs	Generation Flow kcfs	Spill kcfs	Midnight Reservoir Elevation	Average Forebay Elevation	Average Tailwater Elevation	Average Head feet	Project Average Tailwater	2nd Powerhouse Total MWh	2nd Powerhouse Flow kcfs
1	21220	884	96	239.20	238.20	214.70	11.10	75.30	75.30	19.70	55.60	19.50	12921	132.80
2	20301	846	96	222.70	219.70	202.00	5.40	75.40	75.30	18.90	56.40	18.80	12502	126.00
3	20341	848	96	212.40	211.40	197.50	1.50	75.60	75.40	18.10	57.30	18.00	11945	117.10
4	20831	868	96	212.00	218.00	204.00	1.50	75.00	75.40	18.30	57.10	18.20	12469	123.30
5	20639	860	96	216.90	217.90	204.00	1.50	75.10	74.90	18.20	56.70	18.10	12407	123.80
6				214.50	214.50	200.50	1.60	74.80	75.10	18.00	57.10	17.90		120.10
7				205.50	210.50	196.60	1.50	74.40	74.60	17.80	56.80	17.60		116.10
8				188.50	193.50	179.60	1.50	74.00	74.00	16.70	57.30	16.50		105.80
9				186.50	178.50	164.60	1.50	74.80	74.10	15.50	58.60	15.30		100.20
10				179.20	189.20	33.00	143.70	73.90	74.20	16.30	57.90	16.30		33.00
11				189.80	193.80	35.90	145.50	73.50	73.40	16.70	56.70	16.70		35.90
12				214.90	205.90	43.40	150.20	74.40	74.00	17.50	56.50	17.40		43.40
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TOT	103332		480
AVG	20666	861	96	206.84	207.59	156.32	38.87	74.68	74.64	17.64	57.00	17.53	12449	98.13

MAX	21220			239.20	238.20	214.70	150.20	75.60	75.40	19.70	58.60	19.50	12921	132.80
MIN	20301			179.20	178.50	33.00	1.50	73.50	73.40	15.50	55.60	15.30	11945	33.00