Assessment of nonpoint-source nutrient discharges from the Switzer Creek basin, Steuben County, New York

Switzer Creek, tributary to the upper Susquehanna River basin, drains a 3.55 sq mi watershed that is 51% agricultural and 49% forested. From November 1978 to September 1980, Switzer Creek discharged 1,000 tons of suspended sediment, or 0.44 tons/acre. The maximum instantaneous suspended sediment concentration of 3 ,840 mg/L occurred during high water on September 14, 1979. Nitrogen loads, composed of nitrite plus nitrate total kjeldahl nitrogen, totaled 11 and 3.5 pounds/acre, respectively. Eighty percent of the total nitrogen load was transported during base flow. Of the nitrogen load transported during base flow, 88% was nitrite plus nitrate; of the total nitrogen load transported during high flows, 85% was organic nitrogen. Nearly 90% of the phosphorus load was transported during high flows as a result of its affinity for particulate matter. The load of total phosphorus as P totaled 0.63 pounds/acre, and total orthophosphorus as P totaled 0.19 pounds/acre. Nitrite plus nitrate from atmospheric sources totaled 8.4 pounds/acre, and ammonium totaled 3.9 pounds/acre. Equations relate streamflow to concentration and load of eight selected nutrients. (USGS)