Using a hydroeconomic model to evaluate alternative methods applied for the delineation of protection zones

The delineation of wellhead protection zones, especially for water-supply wells, is included nowadays among the most well-known and applied techniques for protecting groundwater quality. To this task, various methods have been developed and are currently implemented, ranging from simple and low-cost to more complex and costly ones. As these methods vary regarding their degree of accuracy and protection, the comparison and evaluation of their outcomes are required, which are usually based on technical criteria (i.e., extent, shape, and form of protection zones). The study takes a step forward by comparing and evaluating three different delineation methods not only on the basis of the - morphological features of the protection zones but also considering some economic and environmental aspects. In this framework, a hydroeconomic model was developed and an economic-environmental indicator - expressed as the ratio of the total cost of implementing a protection zone to the associated environmental benefits - was introduced. In the empirical application of this paper, the protection zones of two water-supply wells, both located in agricultural land, were determined. Furthermore, the application cost and the environmental impact (i.e., decrease in nitrate concentrations) of the protection zones were estimated by implementing set-aside programs specifically designed for each zone.