Geospatial methods to examine shoreline erosion in the Chippewa Flowage: A case study

Abstract

The wind fetch and wave energy of a waterbody are important factors in determining shoreline erosion potential and can influence aquatic community composition. Quantifying and interpreting these variables, however, can be a difficult and time-consuming process without the use of a geographic information system (GIS) coupled with fetch models, such as WAVES (produced by the United States Geological Survey). Examples of the applicability of these tools are limited; therefore, we present a case study to demonstrate the use of these tools in a novel way for understanding lake ecology and guiding lake management. By analyzing hourly wind data, using geospatial methods, and accounting for the abundance of macrophytes, shoreline erosion potential data were generated for Wisconsin's third largest lake, the Chippewa Flowage. GIS-based shoreline erosion potential data showed significant (X2 = 167.17, p ≤ 0.001, df = 2), though not complete, correspondence with an inventory of shoreline erosion from all causes conducted in 1971. A high degree of correspondence was found in wind-exposed areas (X2 = 442, p ≤ 0.0001, df = 2); 1971 erosion sites considered to be in exposed areas had significantly higher average erosion classification than those in more protected areas (p < 0.0001). These shoreline erosion potential data were used for management recommendations to mitigate shoreline erosion and as a variable in ecological analyses of macrophyte communities. © Copyright by the North American Lake Management Society 2012.