Strontium isotopes as a tool for estimation of groundwater recharge and aquifer connectivity

The relationship between 87Sr/86Sr and 1/Sr indicates aquifers' inter-connectivity and suggest that the ophiolite aquifer is recharged from the alluvium and HSG aquifers. Groundwater of the Tertiary aquifer is from: 1) mixture of groundwaters from the ophiolite, alluvium and HSG aquifers and 2) direct infiltration of rainwater and its interaction with evaporite rocks. Mixed waters between those from HSG and ophiolite aquifers is one source of recharge to alluvium aquifer. A mass balance for the ophiolite aquifer was calculated in a binary mixing using the Sr content and the 87Sr/86Sr ratio. The results indicates that about 85-98% of the groundwater of the ophiolite aquifer is recharged from HSG aquifer.