Great Lakes Beaches Research

1. The Problem

The beaches of the Great Lakes are an important recreational outlet, yet because of poor water quality many are often inaccessible due to beach advisories. Existing management approaches have been insufficient in improving the beach water quality as the contribution of all pollution sources, including the potentially significant role of groundwater is poorly understood. To understand the impact of and how to manage the contribution of groundwater to the poor water quality at beaches is complex.

Lake water recirculating through beach sand sets up a reaction zone that controls fate of nutrients discharging from the groundwater to the lake. A reservoir of bacteria often exists in the sand and groundwater near the shoreline.

Understanding the role of groundwater on the water quality at beaches requires knowledge of not only groundwater pollution sources (e.g., septic systems, leaky sewers) but also scientific understanding of the basic processes (hydrological, biogeochemical, and microbial) that affect the movement of pollutants in the groundwater and their release to the shallow lake water. Further, microbial contaminants (e.g., E. coli) accumulate in beach sand and groundwater at the shoreline. It is currently not known if beach sand acts as an important source of contamination and under what conditions bacteria will be transported from the sand to the shallow lake waters. This knowledge is needed to develop effective methods for restoring water quality at beaches and to reduce the frequency of beach closures on the Great Lakes.