Previous Issues

Bahrain brackish water resources occur in the form of a lens of a finite lateral extent with a salinity range between 8 and 15 g/L, developed in the Rus and Umm Er Radhuma formations. The lens has been exploited since 1984 by a well field at an average production rate of 24 mm 3/y in feeding a desalination plant as an alternative to seawater. The purpose of using the lens is to reduce the upward migration of brackish water into the relatively upper fresh water aquifer and to minimize the risk of shutting down the country desalination plants in the case of accidental oil spills in the Arabian Gulf waters. Examination of the response of the brackish water system to the well field pumping over the past nine years shows that the aquifer is undergoing a uniform depletion and no major salinity changes in the produced well field water yet have taken place. This is attributed to that flow towards the well field occurs in the highly transmission fractured zones present in the middle of the aquifer. However, geographical logging indicates that the higher salinity zone underlying the brackish lens has moved into the lower end of the well field interval, which implies that the salinity of the produced water will increase in the coming years. In order to maximize the lens future availability desalination plant, this movement should be delayed.

Modification of the present well field design and artificial recharge are proposed as control measures to achieve that. Simulation modeling of the aquifer system to predict the response of the proposed measures is a pre-requisite to aid future management of the aquifer.