Analysis of Capture Zone and Pump-and-Treat Method in Fractured Rocks

Abstract

A wellhead-protection area, as defined by United States Environmental Protection Agency (EPA 1987), is surface and subsurface area surrounding a water well or well field, supplying a public water system, through which contaminants are reasonably likely to move toward and reach such water well or well field. The travel time-related wellhead protection areas or capture zones of wells are predominantly two-dimensional flow regimes. One of the objectives of a wellhead protection program is the early detection of groundwater contamination in a network of wells installed around the perimeter of a wellhead protection area (Bair et al. 1991). These wells allow sufficient time after detection of a contaminant to plan remedial measures, if necessary, before the contaminants reach the water-supply wells. Many states have been developed regulations to define wellhead protection areas on the basis of the capture zone of wells during specific periods of time. The critical components of a wellhead protection program include: a) determination of groundwater flow pathways, b) delineation of travel time-related capture areas, c) identification of potential source of contamination, d) construction of a network of sentinel wells with a routine sampling regime, and e) implementation of land-use restrictions within the designated wellhead protection area.