SBT-Habitat-Upper Salmon Basin-Dewatered Tributary Feasibility Study

Feasibility study to identify the problems and causes (either natural or irrigation) of dewatered tributary streams in the upper Salmon Basin (from Morgan Creek to the Salmon River headwaters; e.g. Morgan, Challis, Bayhorse, Thompson, Kinnikinic, Squaw, Elk, Gold, Williams, Fourth of July, Champion, Beaver, Pole, Smiley, Frenchman Creeks). Irrigation dewatered creeks were investigated for alternatives with the NMFS and IDFG to evaluate and identify opportunities to get water back into the tributaries for riparian and spawning habitat improvement while creating improved irrigation efficiency (buy-outs, switch to pumps) and connect those tributaries to the mainstem. Worked with experts in NMFS, USFS, IDFG, local residents, and others, to determine the need for and designs of irrigation improvements (screens, water rentals, conversion to pump irrigation, etc.). Reconnection would de-fragment habitat, improve ecosystem function, and may help reduce water temperatures downstream in the main Salmon and would provide access to adult and especially juvenile salmon and steelhead. These creeks provide a valuable and significant role as temperature refuges for juvenile anadromous fish. Preliminary observations indicate that the majority of the problems in the tributaries below Valley Creek occur in the bottom quarter to half mile of each creek. Thus, in six creeks (Morgan to Squaw) where the problem is near the creek mouth, only a total of one to three miles of creek would be re-watered; however, over more than 40 miles of rearing habitat would be reconnected. Conversely, the Valley Creek tributaries (Elk and Gold creeks) and above (Williams to Frenchman Creeks) - referred to as the headwaters of the Salmon River - are replete with a myriad of de-watering problems, both natural and irrigation. This maze of irrigation ditches that cross, re-cross, and connect to each other are not presently a high priority to the IDFG screen shop and the Mitchell Act funds that support screening because these areas are not presently occupied by anadromous fish (SBT disagree). However, the amount of rearing habitat that could be reconnected through resolving this problem may very well be a significant contribution to the recovery of Snake River spring chinook salmon. The actions to solve the problem are elusive. Identifying the problems in the headwaters and laying out alternative solutions can possibly be accomplished in FY 2002, but the actions to resolve these problems may well take more than a year through consultations and collaboration with local water users, governmental agencies, and habitat/hydrology experts. However, due to the importance of these systems to a significant proportion of the total listed Snake River spring/summer chinook population, funding the initial assessment and feasibility work is a priority.

Salmonid habitat including spawning, rearing, migration, and holding habitat will be improved, expanded, and connected.