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Explanation of Flux and Yield

The flux (sometimes referred to as the load) of a river-borne constituent such as nitrate is the amount (mass) that passes a given point on the river over a given period of time. The yield of a river-borne constituent is the flux per unit drainage area. Nutrient flux and yield are calculated as follows:

Nutrient flux = streamflow (discharge) MULTIPLIED BY nutrient concentration in streamwater.

Nutrient yield = nutrient flux DIVIDED BY watershed area.

Nutrient fluxes at a river station are estimated using statistical models with data from a continuous streamflow record at a gaging station and water-quality samples taken at or near the gaging station. The temporal resolution of flux estimates (annual, seasonal, or monthly flux estimates) are limited by the number of water-quality samples collected during the year and the changeability of flow and water-quality conditions at the station.

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Page Last Modified: Tuesday, 06-May-2014 14:36:47 EDT