Quantifying long-term groundwater recharge in transient environments using environmental tracers

Environmental tracers are a useful tool to draw conclusions on long-term groundwater recharge and flow. The challenge lies in finding a method which allows for quantifying realistic recharge under transient conditions, which best reflect the changing climate as well as anthropogenic impacts. This thesis establishes a framework for interpreting radioisotopes in long-term groundwater recharge applications and refines non-parametric methods (specifically, deconvolution) for defining groundwater age distributions using environmental tracers in climates with episodic rainfall events. Both methods expand the scope of using environmental tracers for meaningful interpretation of transient groundwater recharge, especially in arid and semi-arid environments.