Water valuation at basin scale with application to western India

A parsimonious hydro-economic model for a data scarce dryland area is presented. It features a basin level decentralized water allocation mechanism which is adapted to incorporate sustainable water use and to deal with the externalities from upstream-downstream linkages. We formulate the profit maximization problem of various agents in a basin, each identifying a sub-basin, who operate within the boundaries of a spatially explicit model that describes the dominant hydrological processes. We address issues of non-convexities and non-steady state conditions and elicit the dependence of a decentralized water allocation on geophysical properties of the basin. In particular, the approach describes how the competition between the drying and drainage functions of sub-basins in dryland areas manifests itself in the optimal valuation of water. The application to an area of over 500,000 km2 and 34 sub-basins in western India indicates that intra-basin cooperation could be beneficial; valuation of inter basin flows as a percentage of respective sub-basin income is on an average around 30% when each sub-basin includes downstream valuation as well.