Development and Applications of a Wellhead Protection Area Delineation Computer Program

Abstract

In the last few years, groundwater management has concentrated on the protection of groundwater quality. An increasing number of countries has adopted policies to protect vital groundwater resources from deterioration by regulating human interaction with the subsurface, the use of potential contaminants, land use restrictions, and waste transport and storage. One of the more common regulatory approaches to the protection of groundwater focuses on public water supplies to reduce the potential of human exposure to hazardous contaminants. Under the framework of the Safe Drinking Water Act amended by U.S. Congress in 1986, The U.S.EPA (1987) issued guidelines for the delineation of wellhead protection areas, recommending the use of analytical and numerical models for the identification of such areas. In this study, the theoretical background for the development of one such numerical model is presented. Two real-world applications are discussed: in the first case history, the model is applied to a Superfund Site in Puerto Rico as a tool for assessment of the effectiveness of a proposed pump-and-treat scheme for aquifer remediation. Based on simulation results for the evolution of the existing contaminant plume it was verified that such a scheme would not work with the proposed purging wells. The second case history is the delineation of a wellhead protection area in the Town of Littleton, Massachusetts, and subsequent design of a monitoring well network.