Bonneville Dam & Lake on Columbia River

December 2025

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	12814	534	96	131.10	125.10	116.60	1.10	74.40	73.40	11.60	61.80	11.60	10843	99.10
2	12665	528	96	129.60	122.60	114.20	1.10	75.10	74.00	11.60	62.40	11.60	10909	98.80
3	13441	560	96	120.60	129.60	121.20	1.00	74.20	74.30	12.00	62.30	12.00	11085	100.50
4	14329	597	96	133.00	140.00	132.00	0.60	73.50	73.60	13.00	60.60	12.90	11036	102.30
5	14375	599	96	137.20	143.20	134.80	1.00	72.50	73.20	13.60	59.60	13.50	10551	99.50
6	14463	603	96	156.60	144.60	136.30	1.00	73.90	73.90	14.20	59.70	14.20	11069	104.30
7	15236	635	96	148.80	151.80	143.40	1.00	73.60	74.50	14.50	60.00	14.50	11603	109.20
8	15097	629	96	155.20	153.20	144.20	1.40	73.80	74.50	14.90	59.60	14.80	11725	111.80
9	16321	680	96	170.20	165.20	157.30	0.50	74.30	74.70	16.40	58.30	16.40	11476	111.20
10				181.50	169.50	161.60	0.50	75.50	75.30	17.20	58.10	17.20		114.20
11				179.70	197.70	192.50	0.50	73.70	74.60	18.40	56.20	18.30		126.10
12				186.60	203.60	199.20	0.50	72.00	72.40	18.50	53.90	18.30		130.60
13				195.60	196.60	192.20	0.50	71.90	71.90	17.80	54.10	17.60		126.00
14				191.90	183.90	179.50	0.50	72.80	72.40	16.70	55.70	16.50		116.00
15				183.70	184.70	179.10	0.50	72.50	72.50	16.60	55.90	16.40		111.20
16				197.40	193.40	185.40	0.50	72.90	72.90	17.30	55.60	17.00		115.10
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TOT	128741		864
AVG	14305	596	96	162.42	162.79	155.59	0.76	73.54	73.63	15.27	58.36	15.18	11144	110.99

MAX	16321			197.40	203.60	199.20	1.40	75.50	75.30	18.50	62.40	18.30	11725	130.60
MIN	12665			120.60	122.60	114.20	0.50	71.90	71.90	11.60	53.90	11.60	10551	98.80