Artificial drainage is a common agricultural management technique in the United States used to remove excess water from poorly drained soils. Approximately 22.48 million hectares of crop land are drain-tiled in the United States, providing long-term economic benefits to farmers. However, artificial drainage increases sediment transport in agricultural watersheds, which can degrade aquatic systems, destroy habitats, and limit biological diversity. Biotic indices based on benthic macroinvertebrates are commonly used to assess surface water quality, but recent studies show potential in developing sediment biotic indices using benthic macroinvertebrates to estimate fine sediment in streams. The objective of this study was to initiate the development of a biological index that reflects the fine sediment conditions in ditch systems utilizing subsurface drainage in southern Minnesota. Macroinvertebrates, sediment cores, and suspended sediments were collected from agricultural ditches in 2021 and 2022 during severe drought conditions. Fine sediments stored on a streambed ranged between 0.716–100.6 g/m2 in 2021 and decreased to a range of 0.0762–34.28 g/m2 in 2022. Total Suspended Solids decreased from an average of 18.6 mg/L in 2021 to 8.9 mg/L in 2022. The TITAN analyses identified 10 indicator families in 2021 and 5 in 2022, with Heptageniidae being the only family appearing in both years. Calculated FSBI scores ranged from 19-31 and 5-13 for 2021 and 2022, respectively. This project serves as a foundation for future research on the development of fine sediment indices in this region, and demonstrates that the FSBI approach may be a useful tool for assessing stream ecosystem health in Minnesota.


Bertha Proctor

Committee Member

Michael Minicozzi

Committee Member

Nathan Ruhl

Date of Degree




Document Type



Master of Science (MS)

Program of Study

Environmental Science


Biological Sciences


Science, Engineering and Technology



Rights Statement

In Copyright