Evaluation the Hilti/Salahi Recharge Dam in Batineh Area using GIS

By
William Bajjali, Ph.D.
Hydrogeologist & GIS Expert

Brief Introduction

Recharge dams in Oman have been designed and built to store the runoff caused by rain and runoff in order to facilitate its infiltration to the subsurface and exceed the storage capacity of the aquifer.

Hilti/Salahi dam one of oldest and longest dams that have been built in Batina area. The effective capacity and length of the dam are 0.55 Million Cubic Meter (MCM) and 9 km respectively.

The dam had been planned to recharge the groundwater and improve its quality in Batineh area, which has thousands of wells that have been drilled for various purposes and mainly for agricultural use. In wadi Hilti there are 634 production wells that have been drilled and used for number of years, 630 wells of them located downstream of the Hilti/Salahi dam. The groundwater exploitation and the over pumping have caused an increase in water salinity due to salt intrusion or re-irrigation.

The Hilti dam, the groundwater wells and the groundwater chemistry have been integrated into GIS system in order to verify the effect of the dam in the quality of groundwater. The figure below shows the improvement of the water quality downstream of the dam.