Optimizing Patterns of Land Use to Reduce Peak Runoff Flow and Nonpoint Source Pollution with an Integrated Hydrological and Land-Use Model

Abstract

The goal of this study is to develop and apply a methodology for delineating optimal land-use patterns that minimize peak runoff flow at watershed outlets by coupling a hydrological model and a land-use model. Under the assumption supported in prior research that nonpoint source (NPS) pollution is positively correlated with surface runoff volume, the model then yields land-use patterns that minimize nonpoint source pollution. A hydrological simulation model is developed with a modified and spatially explicit Soil Conservation Service (SCS) curve number method to analyze the geographical impacts of land uses. An optimization algorithm is integrated with the simulation model to evaluate different land-use patterns and their response to rainfall runoff events, and to search for optimal land-use patterns. This approach, applied to the southwestern basin of Lake Erie, Old Woman Creek Watershed (Ohio), yields optimal land-use patterns that reduce the peak runoff rate by 15%?20% under 1-, 2-, 5-, and 10-yr storms, compared to the current land-use pattern. The model results provide site-specific land-use guidelines and identify critical areas for conservation.