A lumped parameter modeling approach considering land-cover and land-use for the simulation of karst spring hydrological functioning.

The lumped parameter modeling approach has been widely applied in karst hydrology for, among other applications, the understanding of their functioning of the assessment or groundwater availability in a context of global change. Nonetheless, such an approach generally does not account for land-cover land-use (LCLU) changes and their potential impacts on recharge processes. The study focuses on three forests dominated karst catchments: Kerschbaum (Lower Austria), Baget (French Pyrenees) and Oeillal (southern France), and investigates how LCLU changes in a lumped parameter modeling approach can affect both the internal fluxes and the model performance. The active subspace method is used to perform sensitivity analysis of model parameters, and to quantify parameter uncertainty. We show that the consideration of a semi-distributed recharge constitutes a relevant approach to capture the impact of LCLU changes on flow dynamics, but also introduces more uncertainty in the modeling approach. This approach may thus allow identifying the trade-off between modeling approach complexity and its performance. Finally, it gives new insight for the assessment of LCLU changes impacts on karst groundwater resource.