African Water Development Report 2006 - United Nations Economic ...

African Water Development Report 2006time in one year. The potential and exploitablenon-renewable water resources in the northernsubregion are given in table 4.14 with respect tothe countries of the region. Generally the constraintsof management of non-renewable waterare as follows:(a) The extractable quantities of water are quitelower than the calculated reserves.(b) The depth of pumping is limited technicallyand economically to 250 m. The fast fall ofthe piezometric level limits the possibilityof their exploitation;(c) The exhaustion of this resource is likely topose environmental problems,(d) The sustainability of the projects, which usethis water, is compromised in the long run;(e) This resource has a strategic role which it isnecessary to safeguard for the future generations.The exploitation of fossil water should thus beresource is missing, fossil water shall be used, forexample, only for drinking water, which is notthe case for all the countries of the subregion.Non-Conventional Water ResourcesNon-conventional water resources include agriculturaldrainage water, desalination of brackishgroundwater and/or seawater, and treated municipalwastewater. In this case also the northernsubregion is far ahead of the others. The northernsubregion has, between brackish and sea waterdesalination, a capacity production of about1,400,000 m3/day (table 4.15). The desalinationof water is introduced gradually into the subregionwhen it is the only possible alternativefor the production of fresh water, and when it isjustified economically. Its cost, still high, mainlymakes it still difficult to reach for the countriesof the subregion, mainly the poorest ones, and/orTable 4.14: Potential and Exploitable Non-renewable water in the Northern Sub RegionCountry Non-renewable Water Reserves (Mm3) Exploitable and/or ExploitedMauritania 50 -Morocco 8,000 (annual renewable of 240) 640Algeria 5000 (annual renewable of 800) 1600Tunisia 1400 (53.7% renewable) -Libya. Shared with Algeria and Tunisia, on one hand, andEgypt,Sudan and Tchad2000 (projected)Egypt 20 million 7500Sudan 562000 -Extracted from Draft Sub Regional Synthesis of AWDR National Reports, 2005made only in the event of great need and afterhaving been surrounded by all the precautions toavoid their negative impacts. Generally locatedin arid climate areas, where an alternative waterthose having low potential in energy resources.70