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	16747	698	96	181.50	169.50	161.60	0.50	75.50	75.30	17.20	58.10	17.20	11765	114.20
11	19395	808	96	179.70	197.70	192.50	0.50	73.70	74.60	18.40	56.20	18.30	12570	126.10
12	19196	800	96	186.60	203.60	199.20	0.50	72.00	72.40	18.50	53.90	18.30	12451	130.60
13	18597	775	96	195.60	196.60	192.20	0.50	71.90	71.90	17.80	54.10	17.60	12060	126.00
14	17957	748	96	191.90	183.90	179.50	0.50	72.80	72.40	16.70	55.70	16.50	11476	116.00
15	17994	750	96	183.70	184.70	179.10	0.50	72.50	72.50	16.60	55.90	16.40	11066	111.20
16	18623	776	96	197.40	193.40	185.40	0.50	72.90	72.90	17.30	55.60	17.00	11498	115.10
17	19275	803	96	204.80	206.80	197.40	0.50	72.80	72.60	18.40	54.20	18.10	11796	121.10
18				252.60	239.60	221.90	8.80	74.10	73.10	20.30	52.80	20.10		138.90
19				258.70	263.70	223.20	31.60	73.50	74.00	23.10	50.90	22.80		143.50
20				239.00	245.00	217.10	19.00	73.00	72.70	22.40	50.30	22.10		138.30
21				224.90	216.90	209.80	0.50	73.80	73.00	20.50	52.50	20.30		132.10
22				211.30	203.30	199.10	0.50	74.70	74.40	19.40	55.00	19.30		125.80
23				204.70	196.70	192.50	0.50	75.50	75.60	18.60	57.00	18.50		124.70
24				195.70	209.70	205.60	0.50	74.10	74.10	18.90	55.20	18.70		136.80
25
26
27
28
29
30
31

TOT	276525		1632
AVG	16266	678	96	182.93	182.77	173.17	3.09	73.67	73.65	16.91	56.74	16.78	11469	118.21

MAX	19395			258.70	263.70	223.20	31.60	75.50	75.60	23.10	62.40	22.80	12570	143.50
MIN	12665			120.60	122.60	114.20	0.50	71.90	71.90	11.60	50.30	11.60	10551	98.80