Evaluating non-point nutrient loading in Steamboat Creek, Nevada

Steamboat Creek in western Nevada is the largest contributor of non-point n utrient pollution to the Truckee River, which connects Lake Tahoe to termin al Pyramid Lake. Lands adjacent to Steamboat Creek receive, on average, sev en inches of precipitation annually. Land uses in the Steamboat Creek basin are agricultural, urban, and undeveloped. Steamboat Creek is a complex sys tem due to the presence of numerous irrigation diversions and the Steamboat Springs geothermal area. The Steamboat Creek basin is experiencing urbaniz ation of agricultural and undeveloped lands. Historic water quality data wa s analyzed to identify trends associated with different land uses adjacent to the creek, seasonal flows, and irrigation regimes. Three Lagrangian-styl e water quality surveys were performed-one each during high flow with irrig ation, medium flow with irrigation, and low flow with minimal irrigation. E ach water quality survey occurred during dry conditions and followed dry an tecedent conditions. Hydrodynamics, nutrient flux, and diel variation of di ssolved oxygen concentrations associated with periphyton productivity will be simulated using the Water Quality Analysis Simulation Program Version 5 (WASP5).