Effect of Agricultural Activities on Water Quality Deterioration of Mujib Basin, Jordan

Mujib basin is located at the central part of Jordan, south of the Capital, Amman. The area is bounded by Zerqa basin in the north and Hasa basin in the south, while it extends to Azraq and Sirhan basins in the east and to the Dead Sea to the west. In the hills on the eastern edge of the Valley, the topography is rugged, scarp and steep canyon drops to elevation about 400 m below sea level (bsl) adjacent to the Dead Sea. The Mujib basin is semi-arid to arid, with low rainfall in most parts of the basin in winter and high temperatures in summer. In this study, the 24 water samples were analysed for their physical, chemical and biological characteristics. The analyses were done in November and February, before and after rainy season, respectively. About 12 water samples were collected from Mujib dam and Wadi Mujib and 12 from springs recharging Wadi Mujib and discharge their water from Upper Cretaceous aquifers (B2/A7). According to Langguth classification the surface water shows alkaline earth water with increased portion of alkalies and prevailing chloride. Four types of water were seen in the spring water; alkaline earth water with bicarbonate and chloride, alkaline earth water with increased portion of alkalies with prevailing bicarbonate, alkaline earth water with increased portion of alkalies with prevailing chloride and alkaline water with prevailing chloride. The chemistry of the water is originated from the dissolution of carbonate rocks and evaporates deposits such as Gypsum resulted from irrigation water. The high concentrations of Na+, Cl-,SO4- and NO3- could be attributed to the high probability of water contamination from agricultural activities. The average values for total coliform were ranged from 79 to 1600 MPN/100 ml and from 1.8 to 1600 MPN/100 ml for surface water and springs, before and after the rainy season, respectively. All studied springs have total coliform values exceed the permissible limit according to JS and WHO Guidelines. According to these values, it is not surprising to find high water contamination with total coliform caused by agricultural drainage to the surface water and springs, especially during summer period.