Old and new: Changing paradigms in arid lands water management

Water management paradigms and practices have evolved markedly from the post-World War II years to the twenty-first century. Changes have been particularly urgent and visible in water-limited arid lands. Notable trends include movement from an emphasis on technological, supply-side solutions toward sociological, demand-side management; from rigid top-down state control toward decentralized management; and from local or regional management arenas toward integrated, multilateral formation of water policy from a global perspective. Efforts continue to augment water supplies, but practice has shifted from tactics such as weather modification to energy-efficient desalination, wastewater reuse and, significantly, conservation, which was hardly considered in previous periods of perceived abundance. Overtaking even these efforts in importance is a growing intellectual elaboration of an integrated water management paradigm, which recognizes that each element on both the supply and demand sides of the equation contributes to the total water availability and requires consideration of linkages between urban and rural water use as well as between the domestic, industrial, and agricultural sectors. This awareness has spurred the establishment of "global water initiatives," marking a shift toward globalization of water management to achieve higher levels of integration.