Brett oliver
Coupling Numerical Hydrologic Models with Geodetic Inversions to Illuminate the Role of Fractured Bedrock in Storing and Releasing Water in Mountainous Watersheds
This research develops a novel method to estimate the role of bedrock diffusivity in the terrestrial water budget of three HUC-8 mountainous watersheds. Seasonal changes in terrestrial water storage cause deformation to the Earth’s crust that is within the observational capacity of GNSS instruments. Therefore, this method couples finite difference groundwater simulations with geodetic forward models of crustal displacement to investigate the ability of geodetic deformation to constrain subsurface hydrologic properties. It uses MODFLOW-2005 to simulate groundwater storage and flow and LoadDef to forward model crustal displacement caused by the change in terrestrial water storage calculated by each groundwater simulation. It also performs theoretical sensitivity analyses by simulating changes in deformation as a result of different subsurface properties for a single, synthetic seasonal recharge function. Initial results indicate that the timing and magnitude of vertical crustal displacement are affected by the bulk bedrock hydraulic diffusivity. Varying values of hydraulic conductivity and hydraulic storativity create unique signatures in crustal displacement. This method could improve the bulk parameterization of bedrock within mountainous regions with adequate GNSS network density. This modeling framework offers a new tool to parameterize the subsurface at the watershed scale for numerical groundwater simulations using geodetic observations, which is challenging in mountainous watersheds where extremely limited groundwater data is available.
Brett is originally from the Wet Mountains of southern Colorado. Despite their name, water supply in the Wet Mountains often doesn’t meet the demand of surrounding communities during the annual dry period. Summers under strict water rationing shaped Brett’s passion for water resources in the arid Mountain West, which he continues to pursue in his research at the University of Montana. Brett Oliver is an MS candidate at the University of Montana studying hydrogeology in the Geosciences Department under the guidance of Dr. Payton Gardner.