Evaluation of groundwater in a three-aquifer system in Ramtha area, Jordan: recharge mechanisms, hydraulic relationship and geochemical evolution

Abstract

The groundwater wells in the Ramtha region of Jordan are tapping three aquifers: the upper, intermediate and deep aquifers. The upper aquifer groundwater is tritiated and its stable isotopic composition varies over a wide range. This signifies short residence times and local recharge from an elevation around 600 m above sea level. The groundwater of the upper aquifer has an elevated level of \( {\text{NO}}^{ - }_{{\text{3}}} \), which is attributed to anthropogenic sources. The intermediate and deep aquifers are untritiated and have long residence times. The stable isotope results signify a recharge elevation for the intermediate aquifer higher than that for the upper aquifer. Stable isotopes in groundwater from both aquifers clustered along the eastern meteoric water line and demonstrate association with the dominant climate of Jordan. The groundwater of the intermediate aquifer is classified as Ca2+- \( {\text{HCO}}^{ - }_{{\text{3}}} \), which reflects circulation through a carbonate aquifer. There is evidence that leakage from the upper aquifer has influenced the isotopic and chemical makeup of the groundwater in an intermediate aquifer well. The groundwater of the deep aquifer has the highest temperature in the basin and its isotopic composition is much more depleted than both the upper and intermediate aquifers and plots on the global meteoric water line.