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1. [Image] Lower Klamath River instream flow study : scoping evaluation for the Yurok Indian Reservation
ABSTRACT The U.S. Fish and Wildlife Service, Lower Columbia River Fishery Resource Office was funded by Bureau of Indian Affairs to conduct an instream flow assessment for the lower Klamath River within ...Citation Citation
- Title:
- Lower Klamath River instream flow study : scoping evaluation for the Yurok Indian Reservation
- Author:
- Anglin, Donald R
- Year:
- 1994, 2007, 2006
ABSTRACT The U.S. Fish and Wildlife Service, Lower Columbia River Fishery Resource Office was funded by Bureau of Indian Affairs to conduct an instream flow assessment for the lower Klamath River within the Yurok Indian Reservation in northern California using the Instream Flow Incremental Methodology (IFIM). Specific study tasks consisted of developing an explicit statement of purpose, definition of the study area and target species, assembly and evaluation of hydrologic, water quality, and physical data as well as biological and fish habitat information. A reconnaissance survey of the proposed study area was also conducted. The purpose for conducting the proposed flow study was the Yurok Tribe's desire to protect the Klamath basin water supply for the production of anadromous fish. The ultimate goal was to protect, restore, and enhance the anadromous fishery resources on the Reservation and in the basin as a whole. The study area was defined as the lower Klamath River and tributaries from the confluence with the Trinity River downstream to the area of tidal influence. Although the mainstem Klamath only was proposed for flow studies, the tributaries were included in the study area as a result of their hydrologic and biological relevance. Target species were identified as chinook salmon {Oncorhynchus tshawytscha), coho salmon (0. kisutch), steelhead trout (0. mykiss) , green sturgeon {Acipenser medirostris) , eulachon (Thaleichthys pacificus) , and Pacific lamprey (Lampetra tridentata) . Assembly and evaluation of relevant information was accomplished from results of a public scoping meeting and the review of a large volume of both published and file reports as well as numerous personal communications. Hydrology of the lower Klamath River is affected by U.S. Bureau of Reclamation projects in both the upper Klamath and upper Trinity subbasins. Several hydroelectric projects in the upper Klamath subbasin affect flow patterns, and agricultural activities in the upper Klamath subbasin and tributaries and the Central Valley Project in the upper Trinity subbasin have reduced water yield from the basin. Water quality concerns were identified as elevated water temperatures and nutrient levels resulting from land use activities throughout the basin. Hydrologic and water quality impacts are partially mitigated in the lower Klamath by tributary inflow throughout the basin. The physical environment in the basin has been altered by land use practices and several major flood events. Alterations include loss of riparian vegetation and stream channel stability, loss of soil moisture storage capacity and infiltration potential, debris slides and logjams resulting in migration barriers, reduced supply of large woody debris for recruitment into the stream channel, and sedimentation of spawning and rearing habitat. Fish habitat in most lower Klamath tributaries has been surveyed and deficiencies as well as good quality habitat have been described. Significant production potential exists in most tributaries, however much restoration work needs to be completed to realize the potential. Habitat characteristics for the mainstem Klamath have not been described. Life history and production data are presented for target species and a brief review of sources for suitability criteria is presented. Harvest management and escapement for naturally spawning fall chinook salmon were reviewed from 1978 through 1993. Escapement has varied over the years but a general downward trend in naturally spawning fall chinook can be observed, particularly in recent years. Escapement goals for the Klamath basin varied from 115,000 in 1978 to an "emergency" floor of 27,000 in 1992. Actual escapement of naturally spawning adult fall chinook varied from a high of 113,000 in 1986 to a low of 11,600 in 1991. Escapement in 1978 totalled 58,500 and preliminary estimates of escapement in 1993 were 21,000 naturally spawning adults. Factors affecting production and subsequent stock size and escapement included variable ocean survival, degraded freshwater habitat conditions, the recent six-year drought, releases of large numbers of hatchery juveniles, and harvest management methodologies that have failed to adequately match harvest to predicted stock size. Differential harvest rates for Klamath and Trinity subbasin fall chinook have also complicated attempts to structure the harvest. Field reconnaisance surveys were conducted in spring and summer 1993 for the proposed mainstem Klamath study area. Two distinct river segments were identified based on macrohabitat characteristics. Microhabitat was classified within each river segment and mapped on USGS quadrangle maps. Cross section identification was postponed pending the decision to move forward with the flow study. Following the scoping tasks described above, conclusions and recommendations were developed. No information was reviewed that indicated the need for an instream flow study in the lower Klamath River. The two basic problems affecting anadromous fish production are degraded freshwater habitat and chronic underescapement. Coordination and planning for instream flow studies on a basin-wide scale was recommended. Biological data gaps were identified which need to be addressed before an instream flow study can be completed for the lower Klamath. Suitability criteria for habitat analysis also need to be identified. Habitat restoration and protection and proper management of anadromous fishery resources were identified as the highest priorities to begin restoration of anadromous stocks. Specific recommendations for habitat restoration included watershed and riparian zone restoration, barrier removal, instream habitat inventory, restoration, and monitoring, estuary studies, and description of streamflow characteristics for lower Klamath tributaries. Recommended fishery resource studies included collection of basic life history data, monitoring for adult escapement and juvenile production, description of estuary usage, effects of hatchery programs on both adult and juvenile wild fish, evaluation of the accelerated stocking program, and refinement of harvest management methodologies to achieve appropriate escapement of naturally spawning stocks into all subbasins.