Document Type



In several regions of the Great Lakes, including Saginaw Bay, the proliferation of muck, decaying organics largely from aquatic plants such as Cladophora, has washed ashore, and is blamed for negatively affecting water quality and economic losses in the region. The current view is that excess nutrient loading into the system is a leading cause of this type of organic debris, though changes in food web dynamics may also be a contributing factor. Through an Integrated Assessment (IA) framework, we summarized the current state of knowledge on the causes and consequences of muck conditions at the Bay City State Recreation Area (BCSRA), including the socio-economic impacts of muck at the park and on the Saginaw Bay Region. Through this framework we identify potential management scenarios for addressing beach fouling at the BCSRA. Through a robust stakeholder engagement process, the IA team implemented a suite of models and surveys to understand public perception of muck-related issues and identified a series of feasible short and long-term management actions that could help alleviate and better manage the impacts of muck. Results indicate that even drastic reductions in external phosphorus loads will not eliminate Cladophora growth in the bay. Beach muck is likely a historical part of the system, and nutrient reduction programs may not prevent muck from fouling Saginaw Bay beaches. We identify a sustainable park management practice maybe reallocating resources previously designated for cleaning efforts to achieve bare, sandy beaches and promoting alternative ecological activities and attractions such as bird watching, kayaking, and nature walks in the park’s coastal marshes.


Fresh Water Studies | Water Resource Management


Final report to the Michigan Sea Grant, Project # R/SS-2, NOAA Award Number NA14OAR4170070. Project overview at