Designating Restricted Areas around Drinking Water Sources through an Index-Based Spatial Approach

Abstract

The design of protection/restriction zones around drinking water bodies is not a simple task, as there are many processes that govern transfer of pollutants in corresponding catchments. The width of the protected area is one of the basic factors to be considered when setting up and managing the zones. The presented approach provides a practical methodology for deciding on an optimum protection distance. Its most distinctive outcome is the feasibility of defining protection zones of variable distances for the applications in different catchments, all based on a single scientific reasoning. It basically considers flow travel times within protection zones, subsurface buffer depths, potential diffuse pollution risks from land uses, sediment-bound pollution, and the total utility of land as a resource. Different weighting schemes for merging various factors together and associated sensitivities on the outputs are further examined for providing more realistic assessments than the equiponderant use of the distinctively significant components. By virtue of an unsymmetrical weighting biased more towards the protective parameters, the protection boundary appears essentially to be located at a distance of 5.3 km from the reservoir in the case of Çamlı reservoir catchment under study.