Computer aided evaluation of planning scenarios to assess the impact of land-use changes on water balance

Abstract The impact of land use scenarios on water availability is part of the analysis and evaluation of water resources planning options for a river basin. An increasing demand for proper planning and development strategies indicates the need for robust methodologies to analyse the relation between spatial planning and water resources availability. Such a need can be met, for instance, by means of a simple water balance, which relies on a grid description of the river basin. The distributed character of the basin water balance modelling allows to evaluate the influence of land use changes on runoff availability at any point in the river network, this being limited only by the size of the grid mesh. A pilot study in this direction has been undertaken, aiming at establishing a modular framework, which allows developing a computer aided estimation of impacts of land use changes on total runoff. An application to an actual case area has highlighted major advantages and some limitations of using such an approach in the early phase of planning. An example of such planning illustrates the impact of reforestation on run off and consequently on the expansion of a wastewater treatment plant.