Large-scale coastal wetland restoration on the Laurentian Great Lakes: Determining the potential for water quality improvement

Coastal wetlands around the Laurentian Great Lakes, estimated to cover 1290 km(2) in the USA after extensive losses in the past 200 years, are rarely restored for water quality enhancement of the Great Lakes, despite the need for minimizing phosphorus and other pollutant inputs to the lakes. A simul ation model, developed and validated for a series of created experimental m arshes in Northeastern Illinois, was aggregated and simplified to estimate the nutrient retention capacity of hypothetical large-scale coastal wetland restoration in Michigan and Ohio. Restoration of 31.2 km(2) of wetlands on agricultural land along Saginaw Bay, Michigan, would retain 25 metric tons -P year(-1) (53% of the phosphorus flow from the upstream watershed). Hydro logic restoration of 17.3 km(2) of mostly diked wetlands in Sandusky Bay, O hio, would retain 38 metric tons year(-1) (12% of the phosphorus flow from the upstream watershed). A wetland distribution model developed for the Sag inaw Bay site illustrated a technique for identifying sites that have high potential for being transition zones between open water and upland and thus logical locations for wetland restoration. (C) 2000 Elsevier Science B.V. All rights reserved.