Delineation of Wellhead Protection Areas Containing Seepage Lakes

Abstract

The conventional method of delineating wellhead protection areas using travel times is not well suited for application in wellfields containing seepage lakes. The concentration factor is identified as an intrinsic vulnerability measure that does not have the shortcomings of travel time, and the theory of concentration factors is presented. Idealized scenarios are used to demonstrate the features of using concentration factors. It is shown that using travel times in the presence of seepage lakes can indicate an increased well vulnerability, when in fact there is a reduced vulnerability. It is further demonstrated that in wellfields without seepage lakes, travel times do not give a consistent measure of vulnerability, and concentration factors are a preferred measure.