An economic model of waterlogging and salinization in arid regions

Waterlogging and salinization arise in arid areas largely because two essen tial resources, irrigation water and the assimilative capacity of unconfine d aquifers, are not priced or allocated correctly to reflect scarcity value s and opportunity costs. Farm-level and project-level models of crop produc tion are examined to identify policies that will encourage farmers to consi der opportunity costs and the effects of irrigation and leaching on depth t o regional water tables. Appropriate policies include volumetric water pric ing, water markets, tradable water allotments, adjustments in area-based co st recovery programs, and incentives for farmers to use irrigation methods that reduce deep percolation. Implementing appropriate Versions of these po licies may reduce the rate of increase in waterlogged and saline areas. (C) 1999 Elsevier Science B.V. All rights reserved.