Assessing the Effect of Riverbank Inducement on Groundwater Quality

Over two-thirds of the residents of Wisconsin use groundwater as their source of supply. As populations grow, their expanding demand for water will cause increased competition among users and may exceed the groundwater system’s supply. Wells are commonly installed adjacent to rivers in order to induce water to flow from the river into the aquifer. In parts of southeastern Wisconsin treated municipal wastewater effluent is entering the shallow aquifer via inducement of effluent-containing river water into the shallow aquifer. Because the surface sediments in southeastern Wisconsin are often glacial in origin with highly variable hydraulic properties the efficacy of using riverbank inducement (RBI) as a water source is not obvious. In addition, the close interaction between surface water and groundwater means that the shallow aquifer is vulnerable to contamination and there is worry that direct inducement of river water into groundwater systems will lead to future contamination. Therefore an understanding of effluent movement is needed and the development of a set of markers capable of identifying effluent becomes important. The overall goal of this proposed research is to develop a set of tools that can be used to evaluate the effect of RBI wells on local groundwaters. An existing, well-studied RBI well field located along an urbanized stretch of the Fox River (Waukesha County) will be used as the field site. A large proportion of Fox River flow at this site consists of treated municipal wastewater.