Paper No. 00000 of the Journal of the American Water Resources Association.Discussions are open until October 1, 2001.
DETERMINING NUTRIENT EXPORT COEFFICIENTS AND SOURCE LOADING UNCERTAINTY USING IN-STREAM MONITORING DATA1
Version of Record online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 37, Issue 1, pages 223–236, February 2001
How to Cite
McFarland, A. M. S. and Hauck, L. M. (2001), DETERMINING NUTRIENT EXPORT COEFFICIENTS AND SOURCE LOADING UNCERTAINTY USING IN-STREAM MONITORING DATA. JAWRA Journal of the American Water Resources Association, 37: 223–236. doi: 10.1111/j.1752-1688.2001.tb05488.x
- Issue online: 8 JUN 2007
- Version of Record online: 8 JUN 2007
- nonpoint source pollution;
- water quality;
- export coefficients;
- nutrient loads;
- animal waste;
- uncertainty analysis)
ABSTRACT: Over a three-year period, flow and nutrients were monitored at 13 sites in the upper North Bosque River watershed in Texas. Drainage areas above sampling sites differed in percent of dairy waste application fields, forage fields, wood/range, and urban land area. A multiple regression approach was used to develop total phosphorus (TP) and total nitrogen (TN) export coefficients for the major land uses in these heterogeneous drainage areas. The largest export coefficients were associated with dairy waste application fields followed by urban, forage fields, and wood/range. An empirical model was then established to assess nutrient contribution by major sources using developed export coefficients and point source loadings from municipal wastewater treatment. This model was verified by comparison of estimated loadings to measured in-stream data. Monte Carlo simulation techniques were applied to provide an uncertainty analysis for nutrient loads by source, based on the variance associated with each export coefficient. The largest sources of nutrients contributing to the upper North Bosque River were associated with dairy waste application fields and forage fields, while the greatest relative uncertainty in source contribution was associated with loadings from urban and wood/range land uses.