Tectonic Control of Groundwater Recharge and Flow in Faulted Volcanic Aquifers

Abstract Groundwater dynamics in continental rift zone settings remain poorly understood because of the spatial heterogeneity flow, storage, and recharge dynamics. The Central Kenya Rift is an excellent example where, though groundwater important for domestic, irrigation, geothermal energy exploitation, its hydrogeological properties largely unknown. Existing conceptual models assume flow from high‐elevation, humid flanks to low‐elevation, semiarid floor, but role faults that fracture aquifers commonly unaccounted for. We applied geochemical, isotopic (δ 18 O, δD, 87 Sr/ 86 Sr, 3 H‐ He), multivariate statistical methods, knowledge geological structures determine sources, residence times revise model. Results show primarily recharged by meteoric waters, river input, Lake recharge. impart a control on within four sub‐compartments. Major differences patterns exist between eastern western flanks: surface transfer floor occurs via relay ramp structures, west side takes place laterally high escarpment. Although He dating shows age ranges few >>50 years, most rift‐floor area free H was before 1960s. Hence, we propose these areas receive episodic represent sensitive resources rift. To inform sustainable development, robust monitoring network required capture heterogeneous