ENVIRONMENTAL ISOTOPE STUDY OF THE SHALLOW AND DEEP GROUNDWATERS IN THE AZRAQ BASIN, JORDAN

摘要

The Azraq basin covers about 12 000 km~2 in the semi-arid to arid east of Jordan; it discharges through the two Azraq springs (10.6 m~3/s) and the Azraq Sabkah. The aquifers around Azraq have recently been explored and the water offtake is currently 40 × 10~6 m~3/a or 1.3 m~3/s. As a consequence, one of the two Azraq springs has dried up completely and the discharge of the second has been reduced to about 20% of the original amount.Tritium and stable isotopes indicate an actual contribution of precipitation to groundwater recharge through wadis and ponds. Groundwater recharge has been determined as about 2.7 mm/a on the basis of chloride balances. This result agrees fairly well with the meteorological water balance and covers only 10% of the actual discharge. From this it follows that the dicharge of the Azraq basin must occur under non-steady-state conditions.