Hydro-economic modeling with aquifer-river interactions for sustainable basin management

Abstract

Water demands for irrigation, urban and environmental uses in many arid and semiarid regions continue to grow, while freshwater supplies from surface and groundwater resources are becoming scarce and are expected to decline because of climate change. Policymakers in these regions are faced with hard choices on water management and policies. Hydro-economic modeling is the state-of-the arts tool to assist policymakers in the design and implementation of sustainable water management policies in basins. The strength of hydro-economic modeling lies in its capacity to integrate key biophysical and socio-economic components within a coherent framework. A major gap in developments of hydro-economic models to date has been the difficulty of integrating surface and groundwater flows based on the theoretically correct Darcy equations used by the hydrogeological community. The hydro-economic model presented here specifies a spatially-explicit groundwater flow element. The methodological contribution to previous modeling efforts is the explicit specification of the aquifer-river interactions, which are important when aquifer systems make a sizable contribution to basin resources. This advanced framework is applied to the Jucar basin (Spain) for the assessment of different climate change scenarios and policy choices, specially the hydrologic, land use and economic outcomes. The response to scenarios integrates the multiple dimensions of water resources, allowing results to provide valuable information on the basin scale climate change adaptation paths to guide alternative policy choices using sound science.