University of Minnesota Stormwater Management Practice Assessment Project

St. Anthony Falls Lab and the Water Resources Center at the University of Minnesota present the:

Assessment of Stormwater Best Management Practices Newsletter

A quarterly newsletter designed to share news, current assessment efforts, and contact information related to the development of an assessment protocol for stormwater best management practices.

Projects sponsored by:

Stormwater BMP Effectiveness Evaluation:
Quest for More Accurate, Cheaper, and Faster Methods of Assessment
May, 2006

Executive Summary

As shown on the front page, partnerships are crucial to our quest for improving the assessment of stormwater BMP effectiveness for cities, counties, watershed districts and associated water managers. For more information or if you would like to share information, data, or coordinate efforts, please contact Andy Erickson (eric0706@umn.edu).

This newsletter features:

• What is Stormwater Assessment?
  • 4 levels of assessment include: visual inspection, field infiltration tests, simulated runoff tests, and monitoring
• Project update on Rain Garden Assessment (funded by Met Council)
• Project update on Proprietary Device Assessment (funded by LRRB and Met Council)
• Partner feedback (through voluntary input sessions and TAP meetings) identified priority stormwater BMP devices for this effort: infiltration practices and proprietary devices.
  • Input Sessions
  • Technical Advisory Panel (TAP) meetings
• Assessment method draft status
• Website being developed
• Outreach efforts
• University of Minnesota Duluth is coordinating with the project team to develop a monitoring program for a campus bioretention facility. Water quality, quantity, and weather (via onsite weather station) data will be collected starting this summer.
• Wisconsin DNR is testing stormwater proprietary devices and conducting street sweeping studies
• Urban stormwater runoff effects on trout stream temperatures is currently gathering data and developing a model.

Assessment Protocol Progress

What is stormwater assessment? The assessment protocol currently being developed by the University of Minnesota will propose and explain four levels of assessment:

1. *REFINED* Visual Inspection: Rapid assessment procedure that visually evaluates the effectiveness of a stormwater BMP device. Visual inspections will consist of a set of criteria that can be used to determine whether the stormwater BMP device is not working.
2. *NEW* Field Infiltration Tests: An assessment method that determines the infiltration capacity (hydraulic conductivity) of the stormwater BMP device through a series of point infiltration measurements. Statistical analysis of the results estimates an average infiltration rate of the stormwater BMP device.
3. *NEW* Simulated Runoff Tests: An assessment method that exposes the stormwater BMP device to synthetic stormwater while measurements of infiltration, treatment, and storage are taken. Simulated Runoff Tests can be used to determine volume reduction, peak flow reduction, and water quality treatment efficiency.
4. *REFINED* Monitoring: An assessment method that uses real time data and sample collection equipment to record how a stormwater BMP device treats actual stormwater runoff. The protocol refines and simplifies methods for monitoring to ensure accurate and precise data.

Funds provided by the Metropolitan Council Environmental Services (Met Council) will be used to assess approximately 12 rain garden sites in the Twin Cities metropolitan area. The rain gardens will be evaluated using visual inspection, infiltration measurements and verified using a simulated runoff test. The results will be analyzed for inclusion in the assessment protocol as an assessment method for small stormwater BMP sites. Various infiltrometers and permeameters are currently being constructed at St. Anthony Falls Lab or purchased through vendors. Laboratory and field experiments are scheduled to begin in May.

The field testing of underground proprietary devices is also scheduled to begin in May through a project funded by both Met Council and the Local Road Research Board (LRRB). Four devices from different vendors located throughout the metro have been selected for a field investigation of sediment removal performance. The project team has used information from the pilot studies completed last fall and laboratory experiments conducted over the winter months to revise the testing procedure that will be used this summer. Additional experiments conducted over the winter months were performed to investigate the accuracy and reliability of sampling methods for sediments.

As mentioned in a previous newsletter, many local consultants, city engineers, MS4 representatives, and other organizations gathered in Rochester, Duluth, and St. Paul, MN for voluntary input sessions and gave the project team a wealth of information specific to the local needs in each respective area. The overall conclusion of the input sessions was that rain gardens and other infiltration devices are a key concern in Minnesota and need to be investigated.

The assessment protocol project has hosted two Technical Advisory Panel (TAP) meetings at St. Anthony Falls Lab (SAFL) in Minneapolis, MN. At these meetings, consultants, city engineers, watershed districts, and other organizations specializing in water and stormwater management provide specific guidance on the protocol and the project. On June 30, 2005, the TAP indicated that underground proprietary devices are of interest and also need additional investigation.

The project team hosted the second TAP meeting on February 28, 2006 at St. Anthony Falls Lab in Minneapolis, MN. The TAP reviewed and commented on the following 4 chapters for the assessment protocol:

• Chapter 1: Introduction
• Chapter 3: Water Budget Monitoring
• Chapter 7: Source Reduction
• Chapter 9: Filtration Practices

The next step for the assessment protocol is drafting and reviewing additional chapters thatwill be sent to the TAP for further review as draft copies are completed:

• Chapter 2: Primary Stormwater Treatment Processes
• Chapter 4: Sampling Methodology
• Chapter 5: Water Quality Analysis
• Chapter 6: Testing for Performance Assessment
• Chapter 8: Bioretention Facilities

The project team is also drafting a website where information about the project and drafted chapters will be available for download and printing. The goal of the website is to provide a single location for interested parties to learn about the protocol and get in contact with the project team.

The project team has also been very active in outreach efforts:

• Andy Erickson hosted a poster presentation at the Minnesota Association of Watershed Districts (MAWD) conference in Alexandria, MN on December 1-2, 2005.
• John Gulliver presented at the Minnesota Air, Water, and Waste Environmental Conference (MAWWEC) on the topic of testing and monitoring for stormwater best management practice assessment on February 16, 2006.
• An abstract by Brooke Asleson titled "Assessing Rain Garden Effectiveness" has been accepted for presentation at the National Monitoring Conference which is May 7-11 2006 in San Jose, CA.
• Two abstracts have been submitted to the National Non-point Monitoring Conference (Sept 24-28, Minneapolis, MN)
• Three abstracts have been submitted to the Annual Minnesota Water Conference (Oct. 24-25, Brooklyn Center, MN).

Current/Future Assessment Efforts

These highlights of ongoing work are not inclusive. Contact Andy Erickson (eric0706@umn.edu) with any additional items to share. The overall effort is led by Dr. John Gulliver, department head of Civil Engineering and Dr. James Anderson, co-director of the Water Resources Center at the University of Minnesota.

• University of Minnesota Duluth (part of the Duluth Regional Stormwater team) is coordinating with the project team to develop a monitoring program for a campus bioretention facility. Water quality, quantity, and weather (via onsite weather station) data will be collected starting this summer (Andy Erickson).
• Wisconsin DNR is monitoring proprietary device efficiency for size distribution of soil particles and suspended solids for different land uses and watersheds. Stormceptor® is complete, Downstream Defender® is next. (Roger Bannerman)
• Wisconsin DNR is conducting a study on the effects of street sweeping. (Roger Bannerman)
• Ramsey Washington Metro Watershed District is currently monitoring several sites and intends to monitor its new facility for green roof and porous asphalt effectiveness. (Cliff Aichinger)
• University of Minnesota (UMN) will assess approximately 10 rain garden sites for infiltration effectiveness while developing a protocol for testing infiltration and filtration stormwater BMPs with funds received from Metropolitan Council Environmental Services. (Andy Erickson)
• University of Minnesota (UMN) will assess approximately 4 underground proprietary devices for sediment retention effectiveness while developing a protocol for field testing these proprietary stormwater BMPs with funds received from the Local Road Research Board and Metropolitan Council Environmental Services. (Omid Mohseni)
• Three Rivers Park District is monitoring six (as three paired) watersheds for the effects of restricting phosphorus fertilizers in Maple Grove and Plymouth as well as other practices and sites. (John Barton)
• Dakota County Soil and Water Conservation District is measuring infiltration rates at demonstration rain garden sites using the Turf-Tec infiltrometer commercially available to golf course managers. (Mike Isensee)
• Dakota Soil and Water Conservation District is evaluating rain gardens in the Twin Cities for cold climate infiltration during winter months through a WERF grant. University of Minnesota is coordinating with this effort to continue infiltration measurements throughout the year. (Jim Davidson)
• Partner contract with UMN and MPCA to model the effects of urban stormwater runoff on trout stream temperatures is currently gathering data and developing a model. (Heinz Stefan)

Thank you for taking the time to read this newsletter. If you have any questions or suggestions, please contact Andy Erickson (eric0706@umn.edu).

Sincerely,

Stormwater Best Management Practices Assessment Project Team
Jim Anderson (Principle Investigator) - UMN Water Resources Center
John Gulliver (Principle Investigator) - UMN Department of Civil Engineering
Larry Baker - UMN Water Resources Center
Andrew Erickson - UMN St. Anthony Falls Laboratory
Raymond Hozalski - UMN Department of Civil Engineering
Omid Mohseni - UMN St. Anthony Falls Laboratory
John Nieber - UMN Department of Biosystems and Agricultural Engineering
Heinz Stefan - UMN Department of Civil Engineering
Ron Struss - UMN Extension Service
Peter Weiss - Valparaiso University Department of Civil Engineering
Bruce N. Wilson - UMN Department of Biosystems and Agricultural Engineering