Quality of surface waters in the Al Jabal Al Akhdar region of Oman

Abstract

Al Jabal Al Akhdar (Green Mountain) is the largest structural domain in the western Hajar mountain range of northern Oman, with elevations ranging from 1000 to 3000 masl. It has long been recognized as an important terrestrial ecoregion. Rapid urban and agricultural development in the Jabal Akhdar region of northern Oman is exerting pressure on its water resources. A survey was conducted on the quality of surface waters in the region. Samples were collected from all types of surface waters including man-made reservoirs, aflaj systems, and wedian. Samples were analyzed for temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD5), fluoride, chloride, sulphate, nitrate, sodium, calcium, magnesium, potassium, and trace elements (Ni, Cu, Zn, Cd, Mn, Cr, Co, Fe, V, Ba), coliforms and Escherichia coli. Based on the completed survey of about 40 surface water samples, it can be said conclusively that surface water in the area is not fit for human consumption. All samples clearly failed to satisfy Oman drinking water standards. This study establishes that the most crucial issue is the anthropogenic fecal contamination of surface waters. The eutrophication of all reservoirs is linked to the fecal input from goats and donkeys. Although other types of contamination are rare, there is one distinct case of a falaj contaminated with diesel. Heavy metal concentrations in some sites are not at acceptable levels. The development of the Jabal Akhdar region if not sustainable will inevitably lead to a water crisis involving supply-demand scenarios, water costs and water quality degradation. Management strategies are sorely needed to address these issues.