ABSTRACT
ABSTRACT: Salalah is situated on a fresh water aquifer that is replenished during the annual monsoon season with an average precipitation of 245 mm/year in the highlands of Jabal AlQara to less than 100 mm/year in the Salalah plain, most of which falls during the 3 month long wet season. Salalah plain aquifer is the only source of water in the city for a population of more than the 134,000 inhabitants living in the city. Precipitation in the Jabal AlQara supplies the plain with significant renewable fresh groundwater resources that have allowed agricultural and industrial development to occur. In Salalah city where groundwater is used extensively since the early 1980s for agricultural, industrial and municipal purposes, groundwater is withdrawn from the aquifer more rapidly than it can be replenished by natural recharge. The heavy withdrawal of large quantities of the groundwater from the aquifer leads to the encroachment of seawater. Currently (2005) agricultural activities utilize over 70% of the groundwater. For the last 10-15 years the aquifer is facing acute challenge due to the over-extraction that has taken place since the 1980s and led to salinity intrusion problems. Safe yield has been calculated by the flow model at 51 million cubic meters (MCM)/year, of which 98% of this water is underflow originates from Jabal AlQara, and the remaining 2% is the recharge on plain. The water budget presented in this paper shows that the renewable groundwater resources meet only the 78% of the present demand. The water budget for coming years is predicted and shows that the deficit will increase. The prediction shows that the shallow on-farm wells will virtually lead to the abandonment of farming activities if no solutions are implemented since excess salinity in many wells will occur. The paper suggests a number of recommendations to be taken into account in order to protect the aquifer from further deterioration. A very urgent suggestion of this paper is to take an immediate action to relocate Garziz farm immediately and the fodder production farm of MAF. The two farms located on the freshwater zone and pump currently over 23% of the total discharge for irrigation on the plain. Another measure is to conduct the reuse of the treated wastewater in Salalah plain in order to halt seawater intrusion. These measures would improve the water supply situation for Salalah.
