Bonneville Dam & Lake on Columbia River

May 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	7834	326	96	247.50	244.50	82.50	149.60	73.90	73.40	19.90	53.50	19.90	7518	79.20
2	4893	204	96	225.20	213.20	48.90	151.90	75.00	74.20	18.20	56.00	18.20	4893	48.90
3	7215	301	96	229.80	235.80	73.40	150.00	74.40	74.70	19.20	55.50	19.20	6928	70.40
4	7161	298	96	227.30	235.30	73.80	149.10	73.60	74.00	19.40	54.60	19.40	6473	66.60
5	7610	317	96	243.20	240.20	78.50	149.30	74.20	74.20	19.60	54.60	19.60	6745	69.50
6	5745	239	96	225.50	219.50	57.60	149.60	74.40	74.40	18.60	55.80	18.70	5745	57.50
7	5303	221	96	217.50	214.50	52.50	149.60	74.90	74.40	18.10	56.30	18.10	5303	52.50
8	6393	266	96	226.00	226.00	63.60	150.00	74.80	74.70	18.60	56.10	18.60	6393	63.60
9	6697	279	96	225.40	229.40	67.00	150.00	74.40	74.70	18.80	55.90	18.80	6697	67.00
10	7235	301	96	243.40	235.40	72.60	150.50	75.20	75.00	19.20	55.80	19.20	7235	72.60
11	8729	364	96	246.90	251.90	89.20	150.30	74.70	74.90	20.00	54.90	20.00	8205	83.80
12	6265	261	96	234.00	225.00	62.00	150.70	75.60	75.10	18.70	56.40	18.80	6265	62.00
13	6732	280	96	231.30	230.30	66.10	151.80	75.80	75.80	19.00	56.80	19.10	6732	66.10
14	7358	307	96	228.10	237.10	73.40	151.20	74.90	75.50	19.30	56.20	19.40	6895	68.80
15	8792	366	96	246.50	253.50	91.00	150.10	74.20	74.70	20.40	54.30	20.50	7388	76.60
16	8049	335	96	239.20	245.20	83.60	149.20	73.60	74.20	20.10	54.10	20.10	7034	73.10
17	6832	285	96	235.80	231.80	70.20	149.20	74.00	73.80	19.40	54.40	19.40	6797	69.80
18	6806	284	96	232.30	232.30	69.90	150.00	74.00	73.80	19.30	54.50	19.30	6806	69.90
19	4901	204	96	214.60	211.60	49.00	150.20	74.20	73.90	18.20	55.70	18.20	4901	46.90
20	4102	171	96	212.70	203.70	40.10	151.20	75.00	74.60	17.60	57.00	17.60	4102	40.00
21	3954	165	96	197.30	202.30	38.40	151.50	74.30	74.80	17.40	57.40	17.40	3954	38.40
22	3991	166	96	211.60	202.60	38.70	151.50	75.50	74.80	17.30	57.50	17.30	3991	38.70
23	3380	141	96	174.40	187.40	32.50	142.50	74.20	74.40	16.50	57.90	16.50	3380	32.50
24	3370	140	96	180.20	176.20	31.90	132.00	74.60	74.20	15.40	58.80	15.50	3370	31.90
25	3389	141	96	182.30	182.30	32.30	137.70	74.60	74.20	15.70	58.50	15.80	3389	32.30
26	3371	140	96	184.50	185.50	32.20	140.90	74.50	74.40	16.10	58.30	16.10	3371	32.20
27	3727	155	96	210.60	198.60	35.70	150.50	75.70	75.10	17.10	58.00	17.00	3727	35.70
28	6172	257	96	213.10	224.10	61.30	150.30	74.70	74.90	18.50	56.40	18.50	6172	61.30
29				203.70	210.70	48.90	149.40	74.00	74.30	18.20	56.10	18.20		48.90
30				200.00	200.00	38.60	149.00	74.00	73.40	17.20	56.20	17.20		38.60
31				231.80	223.80	61.10	150.30	74.80	74.20	18.50	55.70	18.50		61.10

TOT	166006		2688
AVG	5929	247	96	220.05	219.67	58.60	148.68	74.57	74.47	18.37	56.10	18.39	5729	56.66

MAX	8792			247.50	253.50	91.00	151.90	75.80	75.80	20.40	58.80	20.50	8205	83.80
MIN	3370			174.40	176.20	31.90	132.00	73.60	73.40	15.40	53.50	15.50	3370	31.90