A Systems Approach to Holistic Total Maximum Daily Load Policy: Case of Lake Allegan, Michigan

Abstract

Systems thinking and system dynamics simulation can provide insights for developing effective plans to protect the environmental integrity of natural systems impacted by human activities. In this study, a system archetype known as growth and underinvestment is hypothesized to explain the eutrophication problem of Lake Allegan in Michigan and identify policy leverage points for mitigation. An integrated system dynamics model is developed to simulate the interaction between key socioeconomic subsystems and natural processes driving eutrophication. The model is applied to holistically characterize the lake’s recovery from its hypereutrophic state and assess a number of proposed total maximum daily load (TMDL) reduction policies, including phosphorus load reductions from point sources and nonpoint sources. It is shown that for a TMDL plan to be effective, it should be considered a component of a continuous sustainability process, addressing the functionality of dynamic feedback relationships between socioeconomic growth, land use change, and environmental conditions.