Water scarcity has always formed a key aspect of life in the Arabian Peninsula, the Mashrek and Mesopotamia. Historically, communities living in these arid and semi-arid regions always shared the water of rivers, springs and wadis, though this was more out of necessity than idealism. Following the creation of modern nation states in the first half of the 20th century, most of the region’s major rivers crossed political borders and were shared between states. Technological advances and large-scale irrigation development in the second half of the 20th century boosted the water and agricultural sectors, fundamentally altering transboundary relations. The damming of major rivers often had negative impacts on downstream water users, especially during the filling of reservoirs. Small-scale dams on tributaries and in catchment areas also impacted downstream flows. While large quantities of surface water were abstracted and increasingly diverted out-of-basin, return flows from large-scale intensive agricultural projects polluted the rivers. Water quality deteriorated, most notably through increased salinity, thus limiting downstream use. In addition, exponential population growth rates throughout the region caused a sharp rise in demand.
Agricultural production also flourished with the introduction of groundwater pumps in the 1960s and 1970s, which resulted in large-scale, intensive development of groundwater. However, the arid climate and low rainfall levels meant that groundwater abstraction quickly exceeded recharge, which in turn led to the drying up of springs, streams and shallow groundwater bodies some of which flowed across national borders. Further advances in drilling and pumping technology allowed for the exploitation of deep groundwater reserves, which were created thousands of years ago and are non-renewable under current climatic conditions. These deep fossil aquifers in the Arabian Peninsula are often highly productive and constitute another, unique kind of shared water resource.
The state of knowledge on shared surface and groundwater resources in the region is largely drawn from the literature available at the global level and reflects the historical context outlined above. Research on surface water resources has tended to dominate the literature. However, information on shared surface water is limited given the political context and national security concerns that are evoked regarding data sharing and exchange. Even less is known about groundwater resources hidden deep underground.
The Western Asia region has no clearly agreed-upon boundaries and various international institutions and agencies define the region differently. The geographical coverage of this Inventory was first determined by the membership of ESCWA, which includes all Arab countries in Western Asia as well as some Arab countries situated in North Africa. This coverage was then modified according to the following four criteria:
- Focus was placed exclusively on shared surface and groundwater resources included in the Western Asia geographic sub-region covered by ESCWA, given that there exists no comprehensive study of shared drainage basins and aquifer systems in this sub-region and there was a clear mandate to examine water resources management within a regional, transboundary context.
- Surface and groundwater resources located on the African continent were excluded from the Inventory. These resources are covered extensively in other studies and are better addressed in an intra-African context, particularly when examining shared water systems.
- As the Inventory is intended to focus on shared water resources, parts of drainage basins or aquifer systems originating in or shared with non-ESCWA member countries are necessarily included in the Inventory. However, as the relevant countries – Iran, Israel and Turkey – are not members of ESCWA, they were not included in the consultative process undertaken with country representatives.
- The study area excludes a number of shared basins in the northern part of Western Asia situated outside of the ESCWA region, but these are to a large extent covered in a similar initiative undertaken by UNECE.
The 'Shared Water Resources in Western Asia' chapter aims to provide the reader with a general overview of the region under study. It starts with a short introduction on the historical development of water resources in Western Asia, and further provides information on the state of knowledge on shared water resources at the global and regional level, outlining existing initiatives and studies undertaken in this context. The second part of the chapter introduces the region under study in terms of geographical extent and also describes its general features such as population, topography, climatic conditions and availability of water resources.