Evaporation rates in this region are high and the sub-surface limestones and marls absorbs much of the runoff except where the ground surface is compacted with clays in wadi stream beds and evaporation pans (qa’as). Precipitation is low (350mm in the north to less than 50mm in the south) and unreliable such that the recharge is minimal. Recharge through precipitation is minimal owing to the aridity of this region with evapo-transpiration rates in excess of 1800mm/year. Water storage is therefore a major problem with users resorting to the extraction of ‘fossil’ water from the aquifers.
Water supply and water quality decrease from north to south. In the north the upper geological sequences contain high quality water, which is at its best east of Safawi – although of limited availability. Towards the Saudi Arabian border the supplies are deeper, more limited and of poorer quality.
Other than subterranean supplies the principal source of water is runoff from the Jebel Druze in Syria where the precipitation is enhanced by snow. The water infiltrates into the basalts and follows the tuff layers beneath the lava flows to appear at the surface as springs in the region of the Azraq basin. Unfortunately water is not only extracted by the northern border villages and farms but is also dammed and used on the Syrian side also. Furthermore water I also abstracted to supply the exploding population of Amman. Whereas in 1965 the authorities were pumping out 4 mill.cu m./yr to day they are extracting in excess of 40 mill.cu.m/yr. Ironically the Azraq Wetland Reserve is now supplied by pumped water.
In Jordan as a whole water consumption exceeds recharge by 140%. Over-abstraction means that the supply is no longer sustainable in the long term and there is a danger of salination of the subterranean water. It is also estimated that loss through old and leaking waterpipes may be in excess of 60%. So critical is the use of water that the Water Authority of Jordan is actively looking into the re-use of water including ground water re-charge.
The provision of domestic and agricultural water is not derived from one single source. There are over 600 wells in the area east of Azraq and around the villages in the northern clusters. Of this water much is lost through inefficient techniques (channels) or inappropriate crops (tomatoes, melons).
The conservation of water resources would seem to depend upon:
- Implementation of surface water stores
- Repair or replacement of old pipe systems
- Better control of water use
- Water rationing
- Less water-demanding crops
- Re-use of waste water
- Rigorous enforcement of illegal wells
Interestingly the Bronze Age people, Nabateans and Romans had their own efficient water collection and storage systems using covered cisterns to reduce evaporation. These were in regular use within the northern villages until they fell into disuse once water was discovered by drilling. Perhaps it is time to revert to the ancient systems?
To improve surface water stores perhaps some research could be undertaken to construct sand dams such as have been developed very successfully in Kenya by the charity known as Excellent Develpoment. Dams across seasonal water courses trap the sediment and hold water within the interstices to be released slowly over time. The provision of such water also has the benefits for sustainable development in a variety of ways.
(www.waj.gov.jo/English/index.htm)
Satellite pictures are by courtesy of U.S. Geological Survey
