King Talal reservoir case study; water quality, treated wastewater use for irrigation and its risk assessment, irrigation type and crop selection

Abstract

According to the World Health Organization (WHO), Jordan is one of the poorest countries in the world in terms of water availability. The amount of water available per capita is 14 per cent less than the world’s water poverty line. Irrigated agriculture is currently the largest consumer (Gunn, 2009). King Talal Reservoir is considered to be the largest supplier for the agricultural sector in the Jordan Valley region. The area planted annually in the Jordan Valley is about 31,600 hectares mainly taken up by irrigated vegetables and citrus orchards. The irrigation water resources for this area are the King Talal Dam, the King Abdullah Canal and runoff from the Zarqa River (Hasan , et al. 2000). This paper aims to study the quality of the King Talal Dam water over a period of four years as most of its water content is a treated wastewater which is coming from Khirbet Al Samra Water Treatment Plant, and Jerash and Baq’a Water Treatment Plants, and to determine the safe use of this water in agriculture and how to choose the crops for this type of water, also to determine if the Jordan Valley farmer's need to change the type of their crops and what is the most suitable water irrigation type depending on water quality, and finally a qualitative risk assessment has been done for using treated wastewater in un-restricted agriculture. This study shows that the localized irrigation system (drip, trickle or splitter) is the most suitable method of irrigation in the Jordan Valley. The high sodium and chloride concentrations prohibit the use of sensitive crops to salinity in Jordan valley's agriculture (FAO Guidelines, 1989), depending on the risk assessment the existing regulations for using treated wastewater in agriculture should be reviewed and issuing a new guide lines for treated wastewater use in irrigation.