Bonneville Dam & Lake on Columbia River

October 2026

Day of Month	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 Flow kcfs
1	84.70	74.70	60.00	2.30	75.40	74.90	7.70	67.20	7.70	57.00
2	81.50	78.50	63.80	2.30	75.60	75.50	7.90	67.60	7.90	62.90
3	69.40	76.40	61.70	2.30	75.00	75.30	7.70	67.60	7.60	60.90
4	84.50	81.50	66.80	2.30	75.40	75.00	8.00	67.00	7.90	64.40
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1

TOT
AVG	80.03	77.78	63.08	2.30	75.35	75.17	7.83	67.35	7.78	61.30

MAX	84.70	81.50	66.80	2.30	75.60	75.50	8.00	67.60	7.90	64.40
MIN	69.40	74.70	60.00	2.30	75.00	74.90	7.70	67.00	7.60	57.00