Protecting Ground water Wells Before Contamination Strikes: A Proactive Approach

摘要

Many public water supply wells are subject to actual or potential damage from releases of contaminants to groundwater. Such wells may be taken out of service due to detection of contaminant concentrations above regulatory or public policy standards, or their use may be reduced for fear of potential contamination. Water suppliers now have more options than ever to proactively protect water production wells before contaminant impact. New technology in the form of geographical information system (GIS) databases is available at a low cost from public sources. These databases allow system-wide threat assessments that identify candidates for protection before contamination has occurred. Developments in hydrogeology enable the demonstration of the necessary hydraulic connection to satisfy legal standards for compensation before impact on well operation, even at levels below maximum contaminant levels (MCLs). Monetary compensation is available even for wells that have not yet been actually impacted by contamination. This paper presents the hydrologic and geochemical factors that must be considered in evaluating the risk to supply wells from pollution sources. These factors include the nature of the contamination, the characteristics of the groundwater flow, the pumping well's construction, and the proximity of the contamination to the well. It also presents the techniques that are used to assess potential risk and allocate responsibility. A case study illustrates the application of these techniques to support a claim for monetary compensation for loss of use of a threatened public supply well. Finally, the legal principles governing the pursuit of such claims are described.