A network of consultants in: water resources, hydrology, hydraulics, hydrogeology and water quality

Arid Zone Hydrology

Arid zones present special problems to hydrologists. Describing the hydrological balance is difficult as very little of the potential evaporation demand is satisfied. Only a small proportion of the rainfall becomes runoff except in extreme storms. Also, rainfall tends to be highly variable in arid regions both in time and space, which leads to very high variability of runoff.

Groundwater can be a major source of water, but similar problems exist in estimating the long-term yield of an aquifer. Recharge of groundwater can be very small in most years but groundwater levels can recover dramatically in a few wet years.

Although surface water is not always a major source of water, it is sometimes feasible to build dams for domestic water supply or for irrigation. Some over-year storage is usually desirable despite the high losses by evaporation because of the high variability of runoff from year to year. Spate irrigation by diversion of flood runoff is also a possibility.

Water Resource Associates has experience of these issues gained through many studies in arid zones primarily in the Middle East and Africa.

Israel, Jordan, Palestinian Authority
WRA has set up and supervised a €2 000 000 project for the European Commission enhancing the capabilities of the three parties to collect and process water related data.

Israel, Jordan, Palestinian Authority
WRA has prepared a project for the real-time transmission of environmental data for the French government. The data will include parameters related to water quality and level of both surface and groundwater.

Chad
Rainfall-runoff and flow forecasting models were developed for the Lake Chad drainage basin for the strategic planning of regional water resources.

Jordan
Analysis of the potential for surface water storage and groundwater recharge in the Hammad and Sirhan basins.

Yemen
Analysis of the statistics of daily rainfall for generation of spate flood series. Regional modelling of spate runoff and the potential for diversion of flood water for irrigation in the Tihama plain.

Yemen
Estimate of flood frequencies for the historic walled town of Shibam.

Oman
Primary water resources survey of northern Oman. Analysis of the impact of spate floods originating from rainfall on Jebel Akhdar on the shallow groundwater storage in the wadi channels and the alluvial plains. Detailed study of the interaction between surface and groundwater flow in the wadi gravels as evidenced by discharges observed in the aflaj (qanat) systems.