Project overview
This study provided a better understanding of the effectiveness of existing sump manholes and catch basins by documenting sediment volume data from actual structures in urban watersheds. Often influent concentrations in urban environments are assumed to have a particle size distribution (PSD) similar to NURP 50 (EPA 1983), and this study addressed if this is a valid assumption for urban watersheds.
This study also illustrated how SHSAM can be used to estimate effective maintenance schedules. Characterization of sump sediments provides a better understanding of the pollutant hazard to the environment. Characterization also provides an understanding of the sediment disposal options available.
Research findings
- Cleaning manhole slumps twice a year allows for much more dirt and debris capture, rather than the usual once a year cleaning.
- Using an average estimation of 400 mg/L of sediment concentration works best for planning
- The overall cost for stormwater sediment capture by sumps is ~$600/cubic foot of dirt removed.
What does this mean for Minnesota?
This project aimed to better understand how to use sump manholes to remove soil particles and other pollutants before they enter stormwater systems. Using the results found, stormwater practitioners will be able to implement practices that will keep our stormwater systems cleaner.
Reports and Presentations
- Research brief 2022
- Final report 2020