ABSTRACT
Extent of Water Scarcity in Dry Areas .................................................................. 452 Declining Agricultural Share of Water ................................................................... 455 Options for Coping with Water Scarcity ................................................................ 456
Developing New Water Supplies ....................................................................... 456 Utilizing Marginal-Quality Water .................................................................... 457 Regional Water Transfer .................................................................................... 458 Rainwater Harvesting ....................................................................................... 459 Import Virtual Water .......................................................................................... 459 Demand Management, Water Pricing ...............................................................460
Increasing Agricultural Water Productivity............................................................460 Evolution of the Water Productivity Concept ................................................... 461 From Efciency to Productivity ........................................................................ 461 The Water Accounting Framework ...................................................................463 Water Productivity Performance Indicators ......................................................464 Economic Water Productivity............................................................................464
Responses to Improve Water Productivity ............................................................465 Decit Irrigation ................................................................................................465 Changing Current Land Use .............................................................................466 Precision Irrigation ............................................................................................466
Case Studies from the Middle East ........................................................................468 Supplemental Irrigation Improves Rainfed Agriculture ....................................468 Improved Water Productivity in Irrigated Agriculture ..................................... 476 Water Harvesting for the Drier Environments-Steppe .................................... 478 WP Improvement and the Environment ............................................................ 481 Policies and Institutions .................................................................................... 482
Conclusions ............................................................................................................ 482 References .............................................................................................................. 483
Water is life, and is absolutely essential to human development and prosperity. It is estimated that nearly one billion people live in the dry areas, where about half of the workforce earns its living from agriculture. The world data on water resources indicates that the West Asia and North Africa (WANA) region, mostly Middle Eastern countries, faces the most serious threat of water shortages (Figure 22.1). Water in this region has shaped up some of the greatest civilizations in the history of mankind along the Tigris, the Euphrates, and the Nile. Since then water has always played a crucial role in the development, stability, and conicts of this region.
