Studies of al Asfar and al Uyoun Evaporation Lakes water quality and the potential of its reuse in agriculture activities, al Hassa area, KSA

Abstract EN

There is a growing concern in the Kingdom of Saudi Arabia to exploit water resources of acceptable quality to meet demands in domestic, industrial, and agricultural sectors.

The agricultural water need constitutes approximately 85 % of the total demand.

Various alternative supplies to meet these demands are considered : Surface water, renewable groundwater resources, treated wastewater, desalinated water, and nonrenewable groundwater.

Al Hassa Oasis is one of the main and old agricultural centers in Saudi Arabia.

An irrigation network of 1, 450 km of concrete canals and drainage network were put into operation in 1971.

The project delivers 328 million m3 of spring water for about 22, 000 farms.

The excess drainage water is collected by earthen drainage network and discharged into two evaporation lakes, which are Al Asfar and Al Uyoun.

Such evaporation lakes (wet lands) are important link between water and land ecosystems.

They provide habitats and refuges for wildlife, flood protection and contribute to abatement of impact of pollution and promoting groundwater recharge.

The aim of this study is to investigate the water quality of these two evaporation lakes of Al Asfar and Al Uyoun and to study the potential of its reuse in agriculture activities at Al Hassa Oasis.

Remote sensing, hydrogeological, chemical studies and Geographical Information Systems (GIS) are implemented to achieve the objectives of this study.

For Al Asfar Lake, fourteen samples from surface water and the isolated water ponds and twenty samples of soil water from the area characterized by shallow water table (≈20 cm depth) have been collected in May to June, 2007.

For Al Uyoun Lake, thirty five samples from surface water and the isolated water ponds and eight samples of soil water have been collected in March to April, 2008.

Through chemical analyses, the major and minor ions content of soil pore water, surface water and sabkha soil samples were assessed.

ArcGIS software and satellite image processing software (ERDAS Imagine) were used for the integration of the output parameters of this study and for visualization of their spatial distribution.

The results indicate that surface water of Al Asfar and Al Uyoun lakes are characterized by relatively low salinity and then encourage to re-treat this considerable quantity of water and to reuse it in agricultural purposes.

This will lead to minimization of the sabkha extension, mitigation of its impact on the nearby farms of Al Hassa oasis and mitigation of aquifer recharge with high saline water and optimization of water use of this surface water body in this arid environment.

The results of this study are important in any future development of the Al Asfar and Al Uyoun areas in planning.