Friends of the Teton River will install a corrugated fish screen and passage return pipe to help protect a priority spawning population of Yellowstone Cutthroat Trout (YCT) from entrapment and mortality in the Desert Canal, the last remaining unscreened irrigation diversion on upper South Leigh Creek. Fisheries monitoring since 2005 has indicated that South Leigh contains the largest allopatric YCT population in the upper Teton River Basin; it contains only native trout and is a major source population for the main stem Teton River. It is estimated that a significant portion of the current population is lost to the canal each year. Installing a corrugated fish screen on this diversion will complete the last major passage improvement project on this perennial headwater stream as a part of a larger suite of projects undertaken since 2008. It will improve safe passage and connectivity for juvenile and fluvial trout migrating between National Forest habitat and the main stem Teton River, greatly reducing the risk of population loss to the canal and improving overall population numbers for pure YCT in South Leigh Creek and the Teton River.