Using Major Ion and Stables Isotopes to Characterize Groundwater Recharge and Hydrochemical Processes in a Mountain-Plain Area: A Case Study in High-Atlas of Marrakech, Morocco

Abstract

Piedmont landscape is especially important as groundwater recharge zones. Determination groundwater recharge origin and qualitatively, evaluate their contribution on groundwater in piedmont area of Haouz plain was based on the use of geochemical and isotopic analysis of groundwater, surface water and springs of the contact zone between the High-Atlas Chain and the Haouz plain.  The correspondence in the space evolution of the various chemical elements of evaporitic origin (SO4^2-, Cl^-, Sr²⁺) in groundwater, piedmont springs, and surface water reveals the existence of recharge water from the adjacent High-Atlas Chain. The various recharge modes of the different aquifers (High Atlas and Haouz plain) determined by isotopic analysis, shows that the source of groundwater both for the alluvial aquifer of Haouz and piedmont seems to be composite between a direct infiltration on the High-Atlas tributaries and a remote recharge from the bordering High Atlas aquifers. Remarkable mountain bloc recharge was observed in the piedmont area near the axis of syncline structures, which have layers of Mesozoic and Cenozoic deposits and control groundwater mineralization both in piedmont and plain.

Keywords: Groundwater recharge, Interaction groundwater-river, Mountain block recharge, Isotopic signature, Hydrochemical process