360 - Understanding the Impacts of Policy and Stakeholder Behavior on Surface Water Quality Through a Coupled ABM + SWAT Model

As a result of widespread and unregulated nonpoint source pollution (NPS), over half of the United States' surface water bodies are impaired. Excessive nutrient concentrations from agricultural runoff exacerbate toxic algal blooms and eutrophication, which degrade ecosystem health and threaten human well-being. As a critical component of the food, water, energy, and environment (FWEE) nexus, water quality management necessitates a multi-perspective system understanding to design effective environmental practices that protect water resources and encourage stakeholder participation. While previous research in optimizing agricultural best management practices (BMPs) and modeling watershed-scale nutrient dynamics have provided valuable insight, such approaches often fail to consider their integration with policy implementation mechanisms and stakeholder perspectives, which can ultimately influence how well water quality management practices are employed. To better understand how stakeholder (i.e., farmer, rural community, industry, and government) behaviors impact water quality in response to different policies and climate conditions, we develop a one-way coupling between an agent-based-model (ABM) and the Soil Water Assessment Tool (SWAT). Considering central Illinois’ Upper Sangamon River Basin and its extensive production of corn- and soybean-based biofuel, we aim to understand how multifaceted biofuel and environmental policies impact land-use management decisions and water quality. Given recent national interest in applying perennial energy grasses (PEGs) (i.e., miscanthus and switchgrass) towards a “greener” cellulosic biofuel economy, we also show how policy changes and a wider adoption of PEGs on marginal farmland can impact stakeholder land-use decisions and improve water quality.