Water quality decisions and policy for an interstate watershed

Abstract

Abstract We develop and apply a dynamic game model with economic, hydrologic, environmental and institutional components for interdependent states to meet water quality goals either jointly or separately. States minimize costs of phosphorus pollution abatement subject to phosphorus dynamics to reach the Total Maximum Daily Load (TMDL) water quality goal across agricultural, urban and stormwater sectors. Comparing noncooperation to cooperation helps delineate key differences in strategies to meet water quality goals. Monte Carlo simulations are used throughout the modeling process to incorporate natural variation in model parameter estimates. Nonlinear and asymmetric cost functions of pollution abatement for each state are estimated from data of each state's implementation of abatement across three sectors. The analysis helps assess how well states achieve the TMDL policy by a government-specified deadline of 2025. Variation in the abatement cost functions across states, sectors and abatement practices within each sector sets the stage to explore sharing of cost minimizing alternatives across all of these scales over time. The least cost option for each state takes into account asymmetry with cooperation across the interstate watershed to reduce total phosphorus load over the time horizon to meet the Clean Water Act goal by the 2025 deadline.