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TN = Total Nitrogen
TP = Total Phosphorus
SS = Suspended Sediment

Nutrient & Suspended Sediment Loads & Yields

Loads and yields represent two methods for describing nutrient and SS amounts within a basin. Loads refer to the actual amount of the constituent being transported in the water column past a given point over a specific duration of time and are expressed in pounds. Yields compare the transported load with the acreage of the watershed and are expressed in lbs/acre. This allows for easy watershed comparisons.

This project reports loads and yields of total and dissolved nitrogen, organic nitrogen, ammonia nitrogen, nitrate + nitrite nitrogen, kjeldahl nitrogen, and phosphorous, total organic carbon, suspended sediment, and inorganic phosphorous. Prior to 2014, load estimation was conducted the Minimum Variance Unbiased Estimator (MVUE or ESTIMATOR) described by Cohn and others (1989). This estimator relates the constituent concentration to water discharge, seasonal effects, and long-term trends, and computes the best-fit regression equation. Daily loads of the constituents were then calculated from the daily mean water discharge records. Beginning in 2014, load estimation was conducted using the USGS developed model, Weighted Regression on Time, Discharge, and Season (WRTDS).