How Much Is Enough? Defining Flow and Lake Elevations Necessary to Provide Healthy and Productive Habitats for Fishes in the Upper Klamath Basin, Oregon

The Upper Klamath Basin supports a variety of fishes including native redband trout (Oncorhynchus mykiss newberrii), and three fish species (shortnose sucker (Chasmistes brevirostris), Lost River sucker (Deltistes luxatus) and bull trout (Salvelinus confluentus)) listed under the Endangered Species Act. The basin also historically supported Chinook salmon (O. tshawytscha) and steelhead trout that are being considered for re-introduction.  The long-term provision of flows and/or water levels that meet the species habitat requirements will be critical to the recovery of the species back to harvestable levels. Commencing in 1991 the U.S. Bureau of Indian Affairs as part of its treaty trust responsibility to the Klamath Tribes and in response to a water rights adjudication, commissioned a series of multi-year studies on three ecologically distinct but interconnected systems within the basin.  These included 22 streams above Upper Klamath Lake (UKL), UKL proper, and a 72 km segment of the Klamath River extending from below UKL to the California-Oregon border. Studies specific to each system were conducted that identified monthly flows or lake elevations to provide healthy and productive physical habitats, lake habitats, and passage habitats to meet the needs of the native species.  This paper defines healthy and productive habitat and describes the primary methods used in defining the flow and lake level needs.