Category Archives: Environment

New Project: Update of Stormwater Management Best Practices Manual

The Local Road Research Board published the Stormwater Best Management Practice (BMP) Maintenance Resource Guide in 2009, and best practices for stormwater management have since evolved. Much has been learned about the benefits and limitations and inspection and maintenance activities of stormwater ponds, bioretention facilities, underground treatment devices, underground detention, and infiltration. Regulatory requirements have also changed as indicated in the Minnesota Stormwater Manual.

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New Project: Sustainable Application of Tire Derived Aggregate in Stormwater Infiltration/Treatment

The reuse of old tires that often end up in landfills has a significant environmental benefit. Tire derived aggregate (TDA), a waste product from automobile tires, can be used in stormwater treatment systems and has shown to be effective at retaining phosphate. However, TDA does not prevent the leaching of metals including zinc and copper.  

Developing media for stormwater infiltration/filtration that uses TDA in combination with materials that can capture metals has several advantages. It would prevent more pollutants from being released into Minnesota’s lakes and streams, save on landfill space and reduce stormwater management costs.

“The use of TDA has been proposed in the past for use in stormwater treatment.  However, local agencies aren’t very familiar with the product being used for this application and have concerns about its potential to contaminate groundwater resources,” said Mark Hansen, city engineer, City of Coon Rapids. “Initial research is showing positive benefits for the use of TDA as a component of the stormwater treatment process, while minimizing its impacts to groundwater.  Using TDA for this application provides a great opportunity to redirect old car tires from landfills and beneficially reuse them to assist in providing stormwater treatment.”

Objectives

  • Select blend materials identified in literature review and mix them in different ratios with TDA.
  • Measure the pollutant removal performance from runoff, leaching of zinc and copper from TDA, and infiltration capacity of each mix.
  • Analyze the observed values to choose the suitable blend material/ratio.
  • Perform lab batch tests to evaluate the potential leaching or removal of polyfluoroalkyl substances (PFAs) by TDA and the blends.
  • Determine impact of biofilms on the leaching of zinc and copper from the mix (Biofilms will be grown on an already defined mix of TDA with blend material).
  • Conduct outreach on project results and implications to management to key stakeholder groups.

Project Details

  • Estimated Start Date: 06/03/2022
  • Estimated Completion Date: 06/30/2025
  • Funding: Local Road Research Board
  • Principal Investigator: John Gulliver
  • Co-Principal Investigator: Meijun Cai
  • Technical Liaison:  Mark Hansen

Details of the research study work plan and timeline are subject to change.

To receive email updates about this project, visit the Local Road Research Board website to subscribe.

Improving Pollinator Habitat Through Cost-Effective Roadside Revegetation

Pollinating insect populations are declining worldwide. Revegetating roadsides after construction offers an opportunity to create pollinator-friendly habitat. Local agencies and MnDOT have new tools and strategies to cost-effectively derive multiple benefits from roadside revegetation efforts. 

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Have Minnesota’s Warmer Winters Increased the Number of Freeze-Thaw Cycles?

Minnesota’s winters have been warming significantly faster than summers over the last several decades. In fact, the state’s winters are among the fastest warming in the U.S. This warming trend is likely increasing the time in which winter temperatures are near freezing, which could increase the number of freeze-thaw events. An increase in freeze-thaw events could have detrimental effects on Minnesota’s pavement systems.

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Environmental Evaluations of Potassium Acetate Used as a Road Salt Alternative

New research explored the environmental impacts of an alternative to road salt—potassium acetate, which is effective on ice at lower temperatures. Minnesota’s winter roads have been effectively treated for decades with chloride-based mixtures for anti-icing and deicing. Salt, however, corrodes steel in vehicles and infrastructure. Additionally, chloride runoff harms the aquatic environment. For example, up to 70% of road salt applied on Minneapolis-St. Paul metropolitan area roads ends up in groundwater aquifers and nearby lakes, many of which exceed regulatory limits for chloride concentrations. 

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Treating Stormwater with Local By-Products Reduces Road Construction Costs, Minimizes Waste

This article was originally published in Catalyst, August 2022.

Ongoing research is looking into the possibility of using local industrial waste for roadside stormwater construction projects. This would help reduce material and transportation costs and put otherwise wasted materials to use.

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Improving Road Safety and Wildlife Conservation With Barrier Fencing

Small animals crossing roads put the animals at risk and present a significant safety hazard to road users. Motorists who suddenly stop or slow to avoid small animals crossing the road can cause significant safety concerns. Motorcyclists and bicyclists risk serious injury if they swerve or hit an animal, as do pedestrians in the road trying to assist the animals. A new, cost-effective fence design was tested and shown to be effective in preventing small animal crossings, benefiting both public safety and conservation. 

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Roadside Safe Spaces for Butterflies and Bees

Pollinators such as rusty-patched bumble bees and monarch butterflies, critical to our eco-system, are at risk due to the loss of native habitat. A University of Minnesota research team, with support of MnDOT and the Local Road Research Board, studied whether restored roadsides could provide safe habitats for declining pollinator populations.

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Expanding Alternative Snow Control Through Landowner Engagement

Some rural landowners maintain snow fences to prevent blowing snow from reaching highways, decreasing the resources MnDOT spends on winter maintenance. A recent project provided new information and updated tools to encourage more landowners to adopt this alternative snow control method.

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Pond Maintenance Strategies to Retain Phosphorus

Cities and counties depend on stormwater retention ponds to protect water quality in lakes and streams. New research sponsored by the Minnesota Local Road Research Board has identified cost-effective methods for ensuring pollutants remain in pond sediment and are not released into other bodies of water.

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