Relationship between dry and wet beach ecosystems and E. coli levels in groundwater below beaches of the great lakes, Canada

There are two types of beaches along the shores of the Great Lakes in Canada: “Dry Beaches’' (dry sand at surface, deep water table, presence of beach grass) and”Wet Beaches’' (damp sand at surface, shallow water table, presence of phreatophytes and turf grass). E. coli is never detected in groundwater below dry beaches but E. coli is consistently detected in groundwater below wet beach. Phreatophytes and turf grass at wet beaches provide an environment and source of food that attracts geese. Goose feces are a source of E. coli. The shallow water table and high moisture content of the sand at a wet beach enables E. coli from fecal material to infiltrate to the water table. At dry beaches, only beach grass is present, and within the dunes, and this does not attract geese. The deep water table and low moisture content in surficial sand inhibits infiltration of E. coli to the water table.