Groundwater irrigation management in the Kingdom of Saudi Arabia： A case study of Al-Wajid aquifer

Groundwater is the primary source for water irrigation in the Kingdom of Saudi Arabia. As a result of lack of basic knowledge on irrigation practices, massive abstractions of groundwater occurred in 1980s. A decision support linear programming （LP） model was developed to help in allocation of optimal groundwater irrigation use, to assess policies implication for water management efficiency, and to estimate welfare impact on producer surplus is developed. Due to massive abstractions occurring in 1980s, Al-Wajid aquifer water levels have dropped in agricultural areas by more than 200 m. The total groundwater of Al-Wajid aquifer that can be saved is equal to 158.7 MCM for the first scenario, 211.9 MCM for the second scenario, and 15,087 MCM for the third scenario. Regarding welfare analysis impact, it is clear that the second scenario alternative is the best alternative, since the value of the producer surplus is the highest for the two study regions and also the two type schemes of modern and traditional irrigation, except the traditional irrigation of Najran region.