IDENTIFYING ALPINE GLACIER MELT INFLUENCED SPRINGS IN MT. HOOD NATIONAL FOREST AND GLACIER NATIONAL PARK USING STABLE ISOTOPES OF WATER

The impact melting alpine glaciers are having on the environment is far reaching; this is causing changes in the agricultural industry, creating natural disasters such as glacial lake outburst flooding in mountainous regions, and loss of habitat for a variety of species. While the relationship between glacial melt and surface-water systems has received a lot of attention, the connection between mountain groundwater and alpine glacial melt is understudied. This topic is critical to future sustainability in alpine communities and ecosystems. Here we test the hypothesis that melting glaciers have an influence on recharge and deep groundwater flow through bedrock. We use stable isotopes of water as the primary method to test this hypothesis.

Stable isotopes of water (∂¹⁸O and ∂²H) have shown to be powerful tools in distinguishing between glacial ice and modern precipitation in catchments around the world, especially when identifying the contribution of glacial melt in rivers and streams, and in shallow aquifers. Field research and data collection including samples of glacial ice, seasonal snowpack, and spring water, were conducted within Mt. Hood National Forest and Glacier National Park in October 2016, July and August 2017, and July 2018. By comparing ∂¹⁸O and ∂²H values from the glacial ice, fresh snow, and springs with varying spatial, geologic, and geomorphic indices, we shed light on understanding how melting alpine glaciers are impacting mountain aquifers. The subsequent analyses and interpretations provide evidence that melting alpine glaciers in these regions are recharging mountain aquifers, directly from the glacier into the bedrock. Implications for this research include better understanding how water-balances in alpine environments are changing with the climate, identifying potential discrepancies in current watershed discharge estimations, and developing new sustainability and water management strategies.