COLUMBIA RIVER FISH MITIGATION
Flow Augmentation
Upstream storage dams hold back water for flood damage reduction and other uses, interrupting the seasonal river flow patterns. Seasonal releases of water from the dams, called flow augmentation, can aid salmon migration. The National Marine Fisheries Service Biological Opinion for salmon contains flow objectives for the Snake and Columbia Rivers, shown on this map, at McNary Dam on the Columbia River and the Lower Granite Dam on the Snake River. The map also shows target limits on reservoir drafts from upstream storage dams to get to the flow objectives. The upstream storage dams are Dworshak and Libby dams (Corps of Engineers), Grand Coulee and Hungry Horse dams (Bureau of Reclamation) and Brownlee Dam (Idaho Power Company).