Saline intrusion is symptomatic of the water management challenges facing many countries in the and zone. On coastal aquifers, it results from the over development of limited groundwater resources leading to sea water intrusion. The challenge is to reduce groundwater abstraction to sustainable levels through the adoption of a management strategy. In developing a management strategy it is necessary to understand the relationship between abstraction and water quality. This study investigated this relationship within the catchments of Wadis Taww and Ma'awil in the Batinah region of the Sultanate of Oman. Over 1994-99 it monitored abstraction, water quality and crops on farms within the catchments. The study also included an investigation of irrigation management on a group of case study farms. The results confirmed the spatial relationship between rates of decline of abstraction and water quality. They show that abstraction is declining by more than ten percent per year within four kilometres of the coast, due to the loss of cropped area. The rate of decline decreasesw ith distance from the coast and with better irrigation water quality. The irrigation study confirmed the potential for improved methods and management. It shows that uniformity of application is low on more than 30 percent of sprinkler and bubbler systems and field efficiency less than 50 percent for surface irrigation. The potential improvements include more systematic scheduling of irrigation rates and frequency. The current trends and the benefit of non-intervention and management intervention, demand and supply, were evaluated using a groundwater flow model. Non-intervention leads to a progressive decline in water use and continued saline intrusion to the year 2041 and beyond. It also shows that high levels of demand management, in excess of a 50 percent abstraction reduction, would be required to significantly reduce the extent of saline intrusion. The development of a supply option, the reuse of treated wastewater for irrigation, reduced the extent of saline by nearly 2 kilometres compared to the nonintervention and demand management cases.

Saline intrusion is symptomatic of the water management challenges facing many countries in the and zone. On coastal aquifers, it results from the over development of limited groundwater resources leading to sea water intrusion. The challenge is to reduce groundwater abstraction to sustainable le...