18-11 Impacts of Drought and Deluge Conditions on Water Supply in a Prairie Tributary Basin of the Missouri River

Session: Shaping a Sustainable Future with Geology in the Twenty-First Century: Geology and Society Division Turns 22

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The Northern Great Plains (NGP) is experiencing significant hydrological fluctuations due to climate-induced changes in precipitation and temperature trends. Although extensive research has been focused on the mountainous headwaters of the Missouri River Basin (MRB), the Missouri Plateau (MP) remains critically understudied, despite its importance for regional water security and agricultural resilience. This study investigates the impacts of climate variability on the cold-region hydrology of the Cannonball River Watershed (CRW), a major yet understudied tributary within the MP. Using the Cold Region Hydrologic Model (CRHM), the study aims to quantify how wetting-cooling and drying-warming climate phases influence hydrologic processes, including snow accumulation, soil moisture, and streamflow generation. To address the data gap in this region and support modeling, three new rainfall and soil moisture monitoring stations were installed across the Standing Rock Sioux Reservation, filling a critical instrumentation gap, as the nearest climate station is up to 35 miles away in some areas. Field-based monitoring of snow water equivalent (SWE), rainfall, soil moisture, and streamflow will be measured from 2024 to 2026 to support the calibration of the CRHM model. Following the two-year calibration period, CRHM will be applied to simulate streamflow over a 33-year period (1991–2024), capturing cold-region processes such as blowing snow redistribution, freeze–thaw infiltration, and evapotranspiration. Preliminary findings from 2025 are consistent with national trends of increased precipitation and localized flooding. Between May 16 and 20, water levels surged by 2.61 meters, averaging 0.65 meters per day, demonstrating the watershed’s acute sensitivity to short-term storm events. Across all three monitoring sites, 27 rainfall events were recorded between June and July, including multiple high-intensity storms (e.g., 48 mm at Sites 2 and 3). The spatial variability and timing of these storms underscore the necessity of distributed monitoring to capture localized hydrologic dynamics. In addition to advancing cold-region hydrology research in the MP, this project integrates culturally responsive education and outreach. Hands-on hydrology workshops are being delivered to Native-serving high schools and professionals from the Standing Rock Sioux Water Resources Department. This partnership between the University of North Dakota and the Standing Rock Sioux Tribe represents a critical step in addressing long-standing data gaps while empowering Native communities to lead in the stewardship of their water resources for generations to come.

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

doi: 10.1130/abs/2025AM-7228

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