Climate change is threatening critical infrastructure across Minnesota. Prepare your community to adapt using a climate resilience planning grant from the Minnesota Pollution Control Agency.
The MPCA is providing $870,000 to Minnesota communities for assessing vulnerabilities and creating plans to adapt to the effects of climate change. The funds can be used to build resilience in three infrastructure areas: stormwater, wastewater, and community-wide.
Projects funded through this grant could include, but are not limited to:
Gauging the impact of stronger, higher frequency storms on stormwater infrastructure
Planning wastewater infrastructure improvement projects to mitigate the impact of increased flooding
Assessing climate risks in community infrastructure such as parks and recreational areas, roads, public buildings, local power infrastructure, etc.
Seeking authentic input from residents and stakeholders on climate adaptation planning
Maintenance is key to ensuring Green Stormwater Infrastructure (GSI) practices continue to function as designed. An often-overlooked part of O&M, particularly for GSI practices, is the design phase. Predicting possible issues before implementation allows us to design practices that minimize O&M issues in the future. There are several common considerations that designers should recognize in the design phase, including the following:
limiting the contributing drainage area to the practice;
performing frequent landscaping maintenance, like trash or weed removal, by incorporating multiple and easy access points;
providing a vegetation design plan when needed; and
installing observation wells for infiltration practices.
Being able to identify items in the design phase will help save time in the future.
The MPCA has been and continues to work on building information on Green Stormwater Infrastructure (GSI) into the Minnesota Stormwater Manual. We have completed updating pages on operation and maintenance for eight GSI practices: bioretention, tree trenches, swales, stormwater wetlands, harvest and reuse systems, permeable pavement, vegetated filter strips, and green roofs. Access the updated O&M pages to get to the updated O&M pages in the Minnesota Stormwater Manual. Each updated page has a section on design phase O&M.
Q. When did Shoreview install their first permeable pavers?
A. Shoreview installed its first permeable articulating concrete block (P-ACB) pavement in 2014 as part of a low-volume city street reconstruction project. Permeable pavement in that project was integrated with the design of the stormwater improvements, and given the specifics of that project, it was the best approach to help meet both city and watershed requirements for stormwater management. The City had prior experience with pervious concrete being used for neighborhood street reconstruction projects in 2008 and 2009.
Q. How many permeable paver installations have been completed?
A. The City has installed P-ACB (permeable) pavements in six separate public street reconstruction projects, the most recent installation in our Edgetown Acres Neighborhood street reconstruction project completed in September 2021. Permeable pavement elements were integrated into the design for public street reconstruction projects in a low-volume, neighborhood street context for 5 of those installations. In 2020, the City used a permeable pavement element in the design for a higher volume, Municipal State Aid Collector road project that has an ADT of 3,300 vehicles per day.
Pressure washing permeable pavers
Q. How often do you conduct maintenance and what does it look like at different times in the year?
A. The city has long had an aggressive schedule for street sweeping; all public streets in Shoreview are swept a minimum of 5 times per year starting in April. Permeable pavement areas are swept on that same schedule, except that there may be additional sweepings following a storm that causes large amounts of organic materials from trees to be on the pavements. Pressure washing can be necessary periodically in some installations depending on land uses next to the roads. Concrete sealants can help slow the degradation of the pavement blocks in areas that are impacted by winter salting operations. These sealants can be applied at the time of construction, and we are setting our budget to assume the need to reapply every 5-10 years after that. Shoreview has developed winter maintenance strategies to dramatically reduce the use of chlorides overall, and refrain as much as possible from using deicers in the areas where our permeable pavements are infiltrating large amounts of meltwater into the ground. All of our permeable pavement streets are plowed in the winter by 1-Ton pick-ups using the same snowplow blades as are used for normal pavements.
Q. What is something that you have learned or the biggest takeaway since installing/maintaining permeable pavers?
A. It's best to apply a sealant to these types of pavement block systems at the time of construction, then monitor them and plan/budget for future applications as necessary. Shoreview experimented with outsourced solutions for pressure washing "trouble spots", but eventually decided on purchasing an $8,500 piece of equipment that is operated by city maintenance staff and integrated into our work program. We also discovered that any manholes within permeable pavement areas need to be sealed to prevent infiltration from water temporarily stored in the rock layer below the pavement blocks. Most importantly, and like any other public asset, these installations will only be as effective as a city's commitment is to maintain them throughout their life cycle.
Q. Any other projects in the future to install permeable pavers?
A. This year, Shoreview completed its Street Renewal Program that began in 1985 where all city streets have been brought up to modern standards as far pavement, drainage, and public utility needs, so we're not planning on using permeable pavements in conjunction with any comprehensive neighborhood reconstruction projects in the near future. There are some larger, relatively higher volume road projects in our 5-10 year plan that may incorporate permeable pavement elements, however. And we are planning on retrofitting permeable pavements into various locations in the city as a response to TMDL targets for water bodies in the community.
Many erosion and sediment control products contain plastics or synthetic fibers that remain on the site long after construction is complete. There are many environmental hazards with leaving products containing plastic onsite. For example: plastic netting from erosion blankets is known to entangle wildlife, netting can get entangled in mowers and also creates a trip hazard long after the organic portions have decayed. Some hydromulches contain synthetic fibers as well as dyes that can break down into toxic components that contaminate soil. Plastic trash left onsite eventually breaks down into extremely small plastic fragments known as microplastics that are turning up in rivers and lakes via stormwater runoff. Once in surface waters, these pollutants are known to harm aquatic life.
Many state departments of transportation, including MnDOT, currently prohibit use of erosion blankets with synthetic fibers. In case you missed it, check out a recording of MnDOT's presentation on use of biodegradable BMPs from this year’s Minnesota Water Resources Conference. MnDOT has a 2020 spec book for Rolled Erosion Prevention Products (REPP) and an REPP Approved Products List for biodegradable blankets.
Using BMPs that can be left onsite to degrade naturally helps reduce the amount of waste that requires disposal at landfills and their associated disposal costs. When there are no plastic alternatives for BMPs available, such as inlet protection devices and perimeter controls, invest in durable products that can be used again and again to save money and reduce waste. In some cases, existing vegetative materials on the site can be used for perimeter control BMPs, such as grinding trees into wood slash for mulch or perimeter control berms.
Wood slash perimeter control
Compost can be used for either perimeter controls or erosion control. Make compost berms or use compost logs or wood chip logs with biogradable sleeves, such as cotton or burlap. Information on use of compost filter berms can be found on EPA's website. Top soil from the site can also be used for perimeter control berms when mulched or seeded with quickly growing vegetation. Leaving existing vegetated strips on the site perimeter or installing sod strips are also effective in managing sediment runoff.
Woodchip perimeter logs and sod
Finally, use construction strategies that avoid needing BMPs in the first place by completing work in one area quickly and phasing grading so the entire site is not exposed at once. Limiting the amount of disturbed area requiring erosion and sediment control BMPs reduces the need for maintenance as well.
When. January 19, 1:00-2:30 PM Central Standard Time
Speakers
Dr. John Chapman, University of Minnesota - discussion of pretreatment and solids
Mike Isensee, Administrator of Carnelian Marine St. Croix Watershed District; and Noah Czech, Stormwater Compliance Specialist, City of St. Cloud - pretreatment practices and approaches in the field
Chris French, National Regulatory Manager and David Wright, Regional Sales Manager, for Bio Clean Environmental - Observations (the good, bad, and ugly)
We’ll also briefly go through pretreatment information in the Minnesota Stormwater Manual. Information on the webinar, including the link to the webinar, can be found in the Minnesota Stormwater Manual. NOTE: Registration is not required and 1.5 pdh will be offered.
Newsletter contact
If you have questions about or suggestions for this newsletter, contact Roberta Getman, MPCA-Rochester, 507-206-2629.
