234-9 Electrical Resistivity Tomography at Frozen Lake: Investigating Water Availability for Mount Rainier National Park in an Alpine Environment

Session: Advance Ground Surface Modeling for Hydrological and Environmental Applications

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Frozen Lake, a high-elevation alpine lake shaped by human and natural processes, serves as the sole water supply for Mount Rainier National Park’s Sunrise Visitor Center (Washington, USA). Declining surface water availability and the need for a secure public water supply necessitates an evaluation of lakebed sediment and water storage potential in this remote and geologically complex area. A combination of remote sensing and bathymetry data estimates that sedimentation has reduced Frozen Lake’s historical capacity of 64 acre-feet to 53 acre-feet based on digital elevation model (DEM) assessments. In combination with the DEM, this study employed a novel open-water application of floating two-dimensional electrical resistivity tomography (ERT) surveys to image the subsurface beneath Frozen Lake, characterize recent sedimentation, and assess water supply potential. The low conductivity of this surface water, complex volcanic and glacial geologic setting, and anthropogenic modifications to the lake present a challenging environment for this investigation. Nonetheless, the integration of ERT models; historical data and geological studies; and recent DEMs enabled realistic bathymetric and subsurface interpretations and recommendations for bolstering the Sunrise Visitor Center’s water supply. This work highlights the efficacy of floating ERT surveys in remote alpine lakes, combining remotely sensed and field-based data in useable interpretations, underscores the challenges of interpreting geophysical data in geologically complex settings, and provides insights into sustainable water management strategies for Mount Rainier National Park.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8565

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