Prediction of Nitrate Concentration in Stream Water Based on Watershed Land Use and Stream Flow Rate

摘要

Non-point source nitrate loading to stream water can be affected by land use, soiltype, slope of discharging watershed, water flow rate, and storm events. This studyconsiders the effects of land use type, water flow rate and seasonal and regional variationin order to understand and predict transport of nitrate in stream water discharging fromwatersheds along Virginia’s Eastern Shore. A simple regression analysis was performedto check the relationship between nitrate concentration and land use type. Fertilizedland was found to be the strongest contributor to nitrate concentration in stream water.Developed land was also a contributor but with a lower weighting factor. Forested landacted as a significant inhibitor. A predictive model was generated using multipleregression analysis. Besides land use type, nitrate concentration was also significantlyinfluenced by stream flow rate. Other variables, including sampled area, seasonal andregional variation, may be treated as background information, in which they may havesome effect on nitrate concentration, but not significantly enough to be included in thepredictive model. Therefore, stream nitrate concentration levels can be predicted alongthe Eastern Shore of Virginia based on land use type and stream flow rate. Predictionsmay be improved by incorporating other geomorphic or hydrologic information.