Secure water supply in water-scarce regions [book chapter]

Abstract

Water security implies the access of water in sufficient quantity and of adequate quality to meet societal and ecological needs. From the supply side, traditional water resources management focuses on the characterization and exploitation of surface and groundwater resources. This chapter discusses other sustainable forms of water supply that could improve water security and thus will become increasingly important in water-scarce regions. Increasing supply is considered after options to manage demand (as described in other chapters of this volume). Water harvesting, for instance, has roots in ancient technologies and has been revitalized over the last decades, promoting its use to maximize the use of rainfall resources and ephemeral rivers. Fog harvesting is rather new but offers a great potential in semi-arid regions. Other technologies such as desalination and water reuse, as well their associated management and policy challenges, are discussed. Particularly challenging are the ecological footprints these innovations produce and the energy implications of expanding their adoption. Nevertheless, they offer considerable advantages in contributing to water security in arid regions. The selection of the most appropriate water supply system to ensure the satisfaction of water needs while maintaining ecosystem functioning and social demands is always a challenge that requires sophisticated tools for multi-objective decision making. Here we discuss some of the most salient issues that are involved in the process, classifying them into the three major criteria of sustainability.