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Yemen Case Study – Assessment of Underground Water
in Wadi Hadramaut by Mathematic Modeling and Exercise Offers

Dr. Prof. Mikhail Kalinin

Central Research Institute for Complex Use of Water Resources (CRICUWR),
Slavinskogo St., Minsk, 220086, Belarus
Tel.: + 375 17 267 05 23, fax + 375 17 267 27 34


For Yemen the most significant problem is to increase the volume of the pumped-out ground water from the artesian wells because of the water depletion. Surface water is formed only due to the atmospheric precipitation. Flood water flows on the surface to the sea faster, then it infiltrates to the water-bearing strata. The temporary ground dams are constructed for irrigation purposes. Drinking water is located underground.

The author had estimated the stock of the underground water on the investigated area for drinking and agricultural purposes. The operational stock was estimated by analytical and mathematic modeling. The map developed on this data might allow conducting the reconnaissance of the underground water. It was stated that a sufficient amount of underground water is located in Wadi Hadramaunt (wadi is an Arabic term for valley with periodic surface flow) where the estimated stock for the next 50 years would be over 10 l/km3/1 sec.
It was suggested to create underground reservoirs for water consumption purposes in arid territories.
The estimation of the natural and operational stock of subsurface water was done for the biggest Wadi Hadramaut by mathematic modeling on the base of data collected by the author.
It was stated, that recharge of the water-bearing strata is replenished by atmospheric precipitation which is not equal in the catchment area and unequally infiltrates to the ground water strata. One part infiltrates directly into limestone of seiwoon suite, second part, collected on the plateau, comes through karst cavities into limestone of Jezza suite, and infiltrates into limestone of seiwoon suite. The third part forms surface run-offs and flows into the main streamflows. It fills soil with water, recharge the alluvial strata within inflow territories and main valley, especially during high waters. The fourth part of precipitation which falls out in Wadi Hadramaunt, evaporates and infiltrates into alluvial-prolluvial sediments. If we take advantage of data on balance of surface waters during the spring of 1981, then we would notice that the first, second and fourth parts take 46% of the water recharge, and the third part - 54%.
Extremely important feature of water intake in the Cretaceous sandstone is the presence of a thick Paleogene limestone layer, which accumulates significant volume of water in storm periods.
As limestone and sandstone are alternated by clay soils, and water, which infiltrates into the clay soils, does not come directly to the lower sandy strata but spreads gradually. It means that limestone substitutes underground reservoirs which feed the main water-bearing strata. The value reaches its utmost in monsoon periods. It helps to keep the precipitation for water-bearing replenishment at a maximum extent in a catchment area and prevent from disperse of water.
Natural stock of the underground waters is estimated in 350 km3 in Wadi Hadramaunt. The main part is located in sandstones. Small amount is placed in alluvial water-bearing strata. Aground 1500 wells need to be constructed for water withdrawal.