Oases are characteristic of the hyperarid areas in or near desert areas. They are typically supplied by ground water or springs, and temporary rivers can also sustain some oases by conducting rainwater (above or below ground) from far away (e.g., the Nile and Draa rivers) to desert depressions. Where oases are fresh, aquatic vegetation and animal life can flourish. They are a foci for people, and human intervention for water use often disturbs standing water habitats in oases so that eutrophication and water withdrawal can cause sustainability problems. The more isolated oases are subject to a hostile climatic ambiance and are usually fairly species poor but are not without interest as specialized insects and amphibians are often abundant. However, where salinity is high, for example in the hypersaline lakes of the Siwa
(Egypt), aquatic life is extremely reduced. Natural oases exist in depressions in the surface of the deserts and can move according to sand dune migration. Some are artificial, and desert people have shown the ingenuity to use water sustainably in dry areas and many oases can be regarded as the product of human effort and will disappear without regular management. Today, traditional water management techniques are declining around oases as technological innovations and finance make it possible to artificially extend water supply to thousands of hectares and 'make the desert flower.' Nevertheless, in many regions overuse of this precious freshwater resource has lowered the groundwater table and exploitation of deep water aquifer resources is now being undertaken.
Was this article helpful?