Optimized Vegetation Buffer Strips Design for Integrated Management of Goodwin Creek Watershed in Mississippi

A principal contributor to soil erosion and non-point source pollution, agricultural activities have a major influence on the environmental quality of a watershed. Impact of agricultural activities on the quality of water resources can be minimized by implementing suitable Best Management Practices (BMPs). The selection and design of these BMPs must be carried out by optimizing both technical and economical considerations. For example, a Vegetation Buffer Strip (VBS), one of the commonly used off-field structural BMPs, can significantly improve the water quality when it is designed and placed correctly. On the other hand, a VBS occupies a portion of the agricultural land that could have been used for crop production, and implementation/maintenance costs are involved. Currently, VBSs are designed (location, plant type, and width) based on field study results, and do not involve a science-based approach to ensure their efficiency under particular regional, climatic, geological and economical conditions. The present study proposes a new approach which integrates computational modeling of watershed processes, fluvial processes in the drainage network and modern heuristic optimization techniques to design cost effective VBSs. The watershed model AnnAGNPS and the channel network model CCHE1D are linked together to simulate the sediment/pollutant transport processes. Based on the computational results, a multi-objective function is set up to minimize soil losses, nutrient concentrations, and total costs associated with installation and maintenance of VBS, while the production profits from agriculture are maximized. The iterative optimization algorithm uses adaptive Tabu search heuristic to flip VBS design parameters. USDA's Goodwin Creek experimental watershed located in Northern Mississippi is used to demonstrate the capabilities of the proposed approach. The results show that the optimized design of VBS using an integrated approach at the watershed level can provide efficient and cost-effective conservation of the environmental quality by taking into account also productivity and profitability.