Avista Operations Overview

• Operational decisions are based upon snow pack and precipitation and temperature forecasts. Forecasts are highly variable due to the relatively low elevation of the Coeur d’Alene basin.
• Flood control concerns overlie all of the balancing of generation, navigation, recreation, fish, and aesthetic concerns.
• Avista takes control of the lake level in the Spring only after inflows recede, the lake is below 2128 and inflows are forecast to continue to trained downward (typically between late May and early July).
• The initial closing of spill gates at Post Falls begins to fill the nine mile stretch of river between Cd’A and Post Falls.
• Avista attempts to hold the lake at or near the summer elevation of the 2128 through Labor Day (subject to a 300 CFS minimum flow requirement).
• The annual draft of the lake generally begins a week after Labor Day and proceeds at a rate of roughly 1.5 foot per month.
• By the first of January, Post Falls is passing all that’s possible through the natural outlet restriction.

• In the fall, Spokane River between the outlet and Post Falls begins to return to its natural unregulated level, where it stays until Avista take control after spring runoff.
• When on “free flow”, the elevation of the river at Post Falls can be 9 feet below summer elevation.
• Low levels bring navigational concerns.