Water quality and invertebrate fauna of farm wells in an area affected by salinization in Oman

The spreading influence of salinity stress on the farmlands of coastal stri p in the Wilayat of Sur, Sharqivah region was investigated. A 4-km study tr ansect was chosen from 2 km from the coast to 6 km inland and three zones b ased on farm conditions were demarcated. Within each zone three farms were randomly chosen and a total of nine farm wells were studied. Irrigation wat er quality clearly indicated that Zones 1, 2 and 3 could be classified as h igh, intermediate and low salinity zones. The improvement of water quality from high to low salinity zones was progressive and statistically significa nt. Seawater intrusion appears to be the cause of degradation in water qual ity. Irrigation water quality of high and intermediate zones was unacceptab le by international standards. Expansion of farms, increased water extracti on and a recharge dam upstream are all considered as factors promoting sali nization. Management strategies for combating salinization are discussed. T he invertebrate assemblages of the study wells have been described and the potential of some sensitive species for use as indicators of salinity stres s is revealed. However, practical difficulties warrant the continued use of chemical methods to monitor salinity changes. (C) 2001 Academic Press.