Using the GIS to Characterize the Groundwater in Dhuleil, Halabat, and Samra Areas, Jordan

Summary

Jordan is a country located in the Middle East. It is an arid area and the desert makes up approximately 90 % of its land mass. The amount of precipitation and the water resources are very scarce and limited. The country mainly depends on groundwater as a main source for domestic water supply and irrigation.

The investigated area is about 490 km2 and it is part of the Amman-Zarqa Basin. In the middle of the sixties a number of wells were drilled for irrigation purposes. After 25 years of groundwater exploitation for irrigation purposes, it has been shown that the water quality has seriously deteriorated. For instance, the salinity rose in some wells from 250 mg/l (1965) to 4000 mg/l (1990). To find a solution to the salination problem and water table drop, Khalidieh Dam with a 1 MCM capacity was built and four wells were drilled in 1983 in order to store the flood water in winter time and inject it into the aquifer to improve the quality and replenish the groundwater.

In 1985 Alsamra Waste Water Treatment Plant (AWWTP) was built in the Samra area with a capacity of 20 MCM to treat the domestic and industrial water of the Great Amman area.

The potentialities of a GIS (ArcView and ArcEdit) as a tool was applied in conjunction with the chemistry and environmental isotopes in studying the hydrochemistry of the groundwater and the water quality in these areas.

The results of the study area and the GIS output maps of the salinity, nitrate, chloride, and stable isotopes show that the deterioration of groundwater is due to the return flow from irrigation and extensive fertilizer applications in Dhuleil and Halabat, while in the Samra area it is due to the effluent of waste water from AWWTP.

The evaporated irrigation water from the soil and the roots of the plants accumulate the salts in the soil, the continuous irrigation from the same groundwater continue to dissolve the salts from the soil which is flushed into the subsurface thereby increasing the salinity. The chloride is the major dissolved anion in the groundwater. The increased nitrate concentration measured in the groundwater wells downstream of AWWTP recorded very high values, in some wells it reached up to 300 mg/l.

The stable isotopes show that the groundwater of meteoric origin and the low calculated deuterium excess (d ) of some water wells is due to evaporation of the return flow before infiltration. The man-made radioactive tritium found in shallow wells in Samra area is evidence of local recharge.

Khalideh Dam serves as an artificial recharge, replenishing local groundwater, thus improving their quality.