Assessment of Underground Stormwater Management Devices under High Flow Conditions (E08PS05)

Project summary:

Numerous technologies have been developed to treat stormwater runoff and remove suspended sediments. Various levels of government have spent millions of dollars on the implementation of stormwater treatment practices over the years. Many commercial stormwater treatment devices are being used because of their small footprint; however, what agencies do not yet know is the performance of these proprietary devices. In 2005, the St. Anthony Falls Laboratory received funding from the Local Road Research Board and the Twin Cities Metropolitan Council to conduct field tests on four devices to assess their performances in treating stormwater runoff. The field tests were completed and preliminary results presented. However, field tests were conducted to determine the performance of the devices for flows up to the maximum treatment rate, and in order to determine whether these devices re-suspend the removed sediments under severe storm events (less frequent storms) and to develop maintenance schedules, further tests on these devices under high flow conditions were deemed necessary. The objective of this research project was to test the effectiveness of these devices under high flow conditions, i.e. to determine whether the devices become a pollutant source or remain a treatment device as bigger storms occur. This research improved the effectiveness of storm water treatment evaluation and implementation through detailed assessment of performance. The results of this study were integrated into the Stormwater BMP Assessment Protocol.