104 A Showcase of Undergraduate Research in Hydrogeology (Posters)

This session is designed for undergraduates presenting research and senior theses in the field of hydrogeology. Prizes will be awarded for top presentations. Employers and graduate advisers are encouraged to attend.

Monday, 20 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

From Pebbles to Profiles: A Baseline Characterization of Substrate and Fluvial Geomorphology in Spearfish Creek

Paper number: 104-7
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Spearfish Creek runs northward approximately 65 km out of the northern Black Hills, western South Dakota, USA. Spearfish Creek is a cold-water stream with ecological, recreational, and hydrological significance to the region. Located in the developing urban area of Spearfish, the creek is subject to both natural geomorphic processes and human impacts. The purpose of this study is to document baseline data of Spearfish Creek, including bathymetry, thalweg, substrate size and distribution, and depth. Conducted as part of a course-based undergraduate research experience (CURE), four 400-m reaches located within the city limits of Spearfish were selected. Each reach consisted of 51 equally-spaced transects (or cross-sections) and 100 synthetic transects with 6 to 11 data points along each transect. Depth, substrate size, and whether the substrate was cemented were recorded at each point, with thalweg measurements also taken at every transect. Bathymetric charts were produced in ArcGIS Pro using Ordinary Kriging interpolation of data collected in the field. Substrate size and cementation maps were produced using the Empirical Bayesian Kriging method. Average depth increased from upstream to downstream being 23, 29, 29, and 32 cm, respectively. Average wetted widths from upstream to downstream were 9.9, 7.4, 7.3, and 6.8 m, respectively, showing a decrease. Cobble was the dominant substrate size in all sites, and the average cementation percentage for all reaches was approximately 49%. These baseline data provide a foundation for future monitoring efforts, geomorphic assessments, and restoration planning. Variations in channel form, sediment composition and distribution, and flow pattern across the reaches

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

doi: 10.1130/abs/2025AM-414607

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