Catchment landforms predict groundwater-dependent wetland sensitivity to recharge changes

Abstract

This study investigates the influence of topography on the desaturation rates of groundwater-dependent wetlands in response to changes in recharge. We examined 60 catchments across northern Chile, which feature a wide variety of landforms. Landforms were categorized using geomorphon descriptors, resulting in three distinct clusters: flat, transitional, and mountain settings. Using steady-state three-dimensional (3D) groundwater models, we derived flow partitioning and seepage area extent for each catchment. Each cluster exhibited consistent seepage area evolution under varying wet to dry conditions. Our findings indicate that mountains have reduced seepage area compared to flats at equivalent hydraulic conductivity to recharge (K/R) ratios but are less sensitive to recharge fluctuations, with slower rates of seepage area reduction. Statistical analyses show that geomorphon-defined landforms correlate with desaturation indicators, enabling the prediction of catchment sensitivity to climate change based solely on topographic attributes.