45 Hydrogeology (Posters)

Added due to amount of discipline abstracts submitted.

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

Impact of Land Use Activities on Nutrient Influx From Farm Fields in a Small Watershed in Iowa

Paper number: 45-4
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

Water quality is a critical issue in Iowa because it impacts water bodies extending all the way to the Gulf of Mexico. Agricultural practices greatly contribute to pollution in Iowa waters, and this study aims to analyze how agriculture impacts the water quality in the Dry Run Creek watershed. This project analyzes Dry Run Creek, which runs through Black Hawk County and Cedar Falls before flowing into the Cedar River. The project also includes four lakes within the watershed to study water quality differences in standing and moving water, and to see if any agricultural impacts are found in the lakes. For the duration of this project, a set of portable water quality sensors were used to conduct on-site analyses of pH, temperature, conductivity, TDS, DO, and turbidity. An HI 98311 EC/TDS meter was used for temperature, electrical conductivity, and TDS (Hanna Instruments, USA). TSS and E. coli were measured, and ion elution was also completed for NO3-, Cl-, and SO4=. Water samples were collected at 14 sites monthly along Dry Run Creek and the Cedar River, and water and sediment samples were collected at four lakes of different sizes in the area. The findings of this study indicate agricultural impacts on the water bodies in the Dry Run Creek watershed. Nitrate pollution is higher in rural areas (70.0-120.0 ppm) than in urban areas (4.0-9.0 ppm), and recorded concentrations increased in the summer months as agricultural practices increased. Chloride levels were generally higher in urban areas (100.0-250.0 ppm) than in rural areas (20.0-30.0 ppm) and tended to decrease over time before beginning to increase at the end of the sampling period. The lake sites did not detect any nitrates and found low levels of chloride (all under 100.0 ppm, except for one lake site) and sulfate (3.0-30.0 ppm). The chloride concentrations did not vary significantly between the different sites over time, indicating background levels and no significant source of pollution. Overall, these water bodies are healthy ecosystems; however, agricultural pollution is apparent and must be monitored. Parts of the Dry Run Creek are currently labeled as an impaired water body, which is why consistent monitoring and management is extremely important.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411740

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