Evaluation of surface water and groundwater resources in watershed planning: comparison between various estimation methods in southern Tuscany

The first step for reaching correct management of water resources in terms of comprehensive planning is to defme the quantìty of water which is potentially available in a given watershed. In this study we present and compare various methods suitable for evaluating surface and groundwater, beginning with the estimation of the total potential resource (water surplus). The study, which was carried out on the main watersheds and subwatersheds in southem Tuscany (Italy), has shown an excellent agreement between the total infìltratìon values deduced from water balance calculations and those obtained with the application of the coefficients of potential infiltration (with deviations lower than 9% in the corresponding water surplus).