USGS/KASIA PRZYBYLA-KELLY

More than 2 million people per year visit Indiana Dunes National Lakeshore with hundreds of thousands enjoying the sandy swimming beaches. The timely and accurate measurement of water quality to protect swimmers’ health has long been a problem for park managers.

Indiana Dunes National Lakeshore comprises more than 15,000 acres (6,075 ha) at the southern tip of Lake Michigan and serves more than 2 million visitors each year. Like all national parks, Indiana Dunes places a high priority on visitor safety. With miles of sandy beaches attracting hundreds of thousands of swimmers annually, attention to swimmer safety plays a big role in park management (fig. 1). Indiana Dunes has improved its ability to protect the health of swimmers through better science-based management and increased understanding of contaminants. Most research has focused on Escherichia coli and its nature, sources, and distribution because it is widely accepted as an indicator of potential pathogens. Though research on E. coli and recreational water quality is continually generating new information, public beach managers may gain valuable insight into this management issue from our experience at Indiana Dunes. This article reviews one of the longest maintained indicator bacteria monitoring programs in the National Park System, highlights lessons learned, and summarizes research findings that may be of interest to public beach managers.