In vast areas of the Mediterranean basin, water scarcity and environmental degradation associated with the pressure on the meager water resources, mainly due to the imbalance between supply and demand, represents an environmental threat and a first-order bottleneck for the economic activities and sustainable development of the involved countries. In addition, arid and semi-arid areas affected by the lack and irregularity (both in time and space) of water resources poses specific challenges that have received little attention, at least not proportional to the magnitude and severity of their problems. It is necessary to underscore the hydroclimatic uniqueness of these territories, which can be included, in general, under the paradigm of arid and semi-arid areas affected by severe water shortages and global water scarcity
In the Mediterranean and similar regions of the world, water resources are limited and subject to severe and growing pressures. Urban and industrial, agricultural, point-source and diffuse pollution, industrial and domestic waste and groundwater overexploitation pose a threat to these scarce resources. River floods are rare but extremely violent and the fragile ecosystems can be threatened by groundwater withdrawals coupled with an inadequate management of surface waters. Moreover, the threat of climate change has to be taken into account, being the Mediterranean a very complex transition area, highly vulnerable to their effects. Depending on the various future scenarios and simulations, it is expected that in the MENA countries, during next century, rainfall will decrease 10-25%, runoff will decline 10-40%, and evaporation will increase 5-20%. In this context it is essential to advance in the knowledge and optimization of all available resources, and new tools and specific policy analysis of rational use of water resources systems are required
Aridity and scarcity of renewable resources, both surface and groundwater, give the non-conventional water resources greater importance than those raised in temperate or humid regions. In some cases, these new water resources could arise as an important part of the overall solutions to be implemented.
Non-conventional is a denomination given to water resources obtained from different sources to those that provide fresh water. FAO defines this concept as total volume of water obtained through the development of new technologies. Moreover, this organization considers that these non-conventional sources of water represent complementary supply sources that may be substantial in regions affected by extreme scarcity of renewable water resources. Such sources, usually counted separately from natural renewable water resources, are related to: a) the production of freshwater by desalination of brackish or saltwater, mostly for urban supply purposes; and b) the reuse of urban or industrial wastewaters (with or without treatment), which increases the overall efficiency of water use (extracted from primary sources), mostly in agriculture, but increasingly in industrial and urban sectors. This category also includes agricultural drainage water
There are near 500 million inhabitants and more than 250 million annual visitors (tourists) in the countries facing the Mediterranean. It is foreseen that this population will increase by 90 million inhabitants in the short-medium term. Moreover, almost 200 million inhabitants live in areas with less than 1,000 m3/capita. In fact, water scarcity in Mediterranean region is among the highest in the World. For instance, 7 out of the 9 SWIM countries (Algeria, Egypt, Israel, Jordan, Lebanon, Morocco, the Palestinian territory, Syria and Tunisia), during year 2010, had less than 500 m3/capita of sustainable fresh water. It is evident that there is a trend towards the worsening of current problems, as a result of the scarcity and therefore the lack of availability of water resources
Solutions that were put forward at the 5th World Water Forum, both in the Istanbul Water Guide and in the subsequent Ministerial Declaration, while indicating that the major challenges to be faced in water management over the coming years will be the population growth and migratory movements, as well as changes in land use, the increase in pollution, and all issues resulting from global changes, which advocate for decisions to be made such as the inclusion of national strategies for improved groundwater management and a greater investment for the reuse and desalination of water