A decision support system for analysing the impact of water restriction policies

The overall objective of the “Design of a Integrated Ground Water Management System. Application in the aquifer system 08.29 in Mancha Oriental, Spain” project (GESMO), financed by the Spanish government, is to research into new software tools for managing water resources in the agricultural environment. This paper presents a decision support system (DSS) developed within that project. The goal of the system is to assist Eastern Mancha Central Irrigation Board authorities to evaluate water use policies that combine the sustainability of natural resources with regional economic development, which is effectively based on irrigation farming. For this purpose, two different models were integrated within one and the same computer application. One is a hydrogeological model able to simulate the River Júcar basin and its associated aquifer. The other is an econometric model capable of statistically predicting the evolution of the regional crops map, the crop yields and the associated prices, thus allowing for the determination of the regional gross product of crops. A combination of both models can be used to compare the reserve of ground water with the product generated using it as a resource, thus making easier to identify the policies that best combine both factors. The scope of this work is the whole river Júcar aquifer (which is the second largest in surface in Spain) and the lands irrigated by it. Functionally, the hydrogeological model is based on finite differences in accordance with the Modular Three-Dimensional Finite-Difference Ground Water Flow (MODFLOW) model developed by the US Geological Survey (USGS), whereas the econometric model is supported by statistical techniques. An important effort have been made in coupling both models as a feedback cycle allowing for a dynamic scenario assessment. Technically, the DSS is conceived as an integrated tool which has been implemented in Visual Basic with a database associated. Its architecture could be translated to other regions without significant programming changes, only introducing new particular parameters into the database.