Recent listing of Columbia River salmon and steelhead runs under the Endangered Species Act has led to efforts to recover fish populations. There are several causes for the original population declines and not all of these are clearly understood, making the direction of the recovery effort uncertain and controversial. A number of remedial actions have been undertaken or are proposed; some of these have conflicting impacts. After a historical review of the problem, a specific example of flow augmentation in the Snake River basin is described in detail. Flow augmentation has been implemented to increase discharges in the Snake River in late summer when fall run chinook salmon smolts are outmigrating. The major source of extra water is from storage in the Dworshak Reservoir on the Clearwater River. A secondary benefit is that selective withdrawal allows the release of cold water from the reservoir, lowering Snake River temperatures at a time when water temperature often exceeds levels deemed harmful to salmonid species. Reservoir releases must be passed over the Dworshak Dam spillway due to insufficient hydrolectric generating capacity; this leads to nitrogen supersaturation in the downstream flow often exceeding total dissolved gas standards. Numerical modeling was used to examine the impacts of different proposed scenarios for water releases from Dworshak Reservoir.