Brendan McGinn holding a trout, Wind River, WYElectrofishing on the Wind River in WyomingDead fishDry conditions on the Wind River, 2003

Fish Losses Associated with Irrigation Diversions on the Wind River Indian Reservation, Wyoming

Principal Investigator: Eric Bergersen

Graduate Student: Brendan McGinn

Project Start Date: 04/18/02

Expected Completion Date: 06/30/05

Funding Agency: USGS, Science Support Partnership (RWO 70)

Introduction: Previous sampling has indicated that great numbers of fish (both native and non-native) are lost each year in irrigation ditches and canals on the Wind River Indian Reservation. However, few researchers have attempted to quantify the total fish loss for an entire irrigation season. Recreational opportunities and management goals may be compromised by these fish losses.

Objectives: 1) Quantify the total losses of native and non-native fish species on the Wind River Indian Reservation associated with irrigation diversion. 2) Evaluation the timing and extent of losses as they relate to diversion schedules and volume. 3) Review fish screening research and development and make recommendations to the tribes regarding the best management practices to reduce or eliminate fish losses.

Progress: A field season was completed during the summer 2002. Three canals (Winchester Ditch, Ray Canal, and Dinwoody Canal) were sampled using electrofishing techniques and various nets. Population estimates ranged from 40,000 fish in the Winchester Ditch to 100,000 fish in the Ray Canal. In addition, at the end of the irrigation season, a salvage sampling was conducted on two canals. The second field season for the project was completed during the summer 2003 irrigation season. Seven canals (Ray, Coolidge, Sub-Agency, A-Canal, Winchester, Johnstown and Left-Hand) were sampled systematically using 3-pass electrofishing techniques. In addition, seven canals (Dinwoody, Coolidge, Sub-Agency, A-Canal, Winchester, Johnstown and Left-Hand) were sampled with modified trap nets to measure the rate of fish entry. Population estimates for each site were computed using Program CAPTURE. Net data was analyzed in SAS.

Preliminary results suggest that approximately 500,000 fish were lost to the irrigation canals during the 2002 and 2003 irrigation seasons. Also, the number of fish entering a canal does not appear to have a strong relationship with variations in flow. For the remainder of the project, the plan is to complete the data analysis, present results to funding agencies and public, prepare reports for funding agencies, finish the thesis, and prepare manuscripts for publication.

Results/Products:
McGinn B.M., 2005. Native and non-native fish losses associated with irrigation diversions on the Wind River Reservation, Wyoming. M.S. Thesis. Colorado State University, Fort Collins, CO 80523, USA.

McGinn B.M., April 2004. Determining the extent of native and non-native fish loss on the Wind River Reservation caused by irrigation water diversions. Public Meeting sponsored by the Wind River Alliance. Ethete, WY.

McGinn B.M., April 2004. Determining the extent of native and non-native fish loss on the Wind River Reservation caused by irrigation water diversions. Wind River Reservation - Bureau of Indian Affairs – Irrigation Division. Fort Washakie, WY.

McGinn B.M., April 2004. Determining the extent of native and non-native fish loss on the Wind River Reservation caused by irrigation water diversions. Colorado State University - Departmental Seminar of Fish and Wildlife Biology. Fort Collins, CO.

McGinn B.M., April 2004. Determining the extent of native and non-native fish loss associated with irrigation diversions. Colorado State University - Student Chapter of the American Fisheries Society. Fort Collins, CO.

McGinn B.M., March 2004. Determining the extent of native and non-native fish loss on the Wind River Reservation caused by irrigation water diversions. Western Division Annual Meeting of the American Fisheries Society. Salt Lake City, UT.

McGinn B.M., April 2003. Determining the extent of native and non-native fish loss associated with irrigation diversions. Wind River Tribal Water Board. Fort Washakie, WY.