After road construction, soil in revegetation areas must retain adequate stormwater and provide stable embankments along the road. Revegetation can be challenging due to thin topsoil, and it often requires importing healthy organic soil and exporting excess construction soil generally unsuitable for plant growth.
Continue reading Reusing Local Byproducts in Sustainably Designed SoilsCategory Archives: Environment
Assessing Culvert Designs for Aquatic Wildlife Capabilities and Future Resiliency
Culverts that influence the speed, depth or flow of a natural waterway can have a detrimental impact on fish populations. By assessing sites across the state, MnDOT sought to identify the effects the culverts have on aquatic wildlife currently and project what potential flooding and drought scenarios could mean in the future.
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New Project: Identifying Deer-Vehicle Collision Concentrations in Minnesota
Deer-vehicle collisions are a significant risk to public safety on Minnesota roads—causing injuries and death for humans and animals, and property damage. Minnesota ranks among the top 10 riskiest states for deer-vehicle collisions in the nation.
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New Tools and Protocols for Successful Infiltration Facilities
Roadside infiltration facilities like wet ponds and swales have been used for more than 30 years to filter roadway contaminants from stormwater runoff, but they have a high rate of failure due to inaccurate determination of soil infiltration rates.
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Using Noise Barriers and Snow Fencing to Capture Solar Energy
During the past decade, MnDOT has been developing solar projects and actively pursuing cost-effective energy-efficiency measures. Among the potentially effective innovations the agency has considered is adding solar panels to noise barriers and snow fences, transforming these single-function installations to multifunction installations. The electricity generated from this practice could offset installation costs and eventually generate revenue for other purposes.
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Ultrasonic Devices Deter Bats During Bridge Repair
Researchers tested ultrasonic bat deterrence devices at two MnDOT bridges, tracking bat activity with acoustic echolocation recorders and field inspections. Deterrence devices used in short- and long-term trials dramatically reduced bat activity at bridge site. Analysis showed that bats return promptly when devices are turned off.
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New Project: Comparison of Compost and Proprietary Soil Amendments for Vegetation Establishment
After road construction, the adjacent disturbed soil has a diminished capacity to sustain vegetation, overall soil health is compromised from soil disturbance and there is an increased risk for erosion.
Soil quality in these areas can be replenished by importing topsoil (the preferred choice) or using organic composts. If organic compost is not available, proprietary soil amendments provide a cost-effective alternative. But information regarding the effects, mix ratios and application techniques for these products is limited. Research is needed to better understand optimal organic compost ratios and how to integrate these amendments to improve soil quality.
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Stormwater Bioslope Site Monitoring Continues Using Local Filter Media
MnDOT and local agencies control stormwater runoff from roadways through a range of settlement, filtration and infiltration facilities, such as wet ponds, infiltration basins, trenches and swales. Infiltration facilities have been used for more than 30 years, but a high rate of failure has been tied to inaccurate determination of soil infiltration rates. Researchers developed new tools and protocols to provide designers and engineers with the accurate infiltration measures they need, from initial site selection through construction. These tools and methods will support the development of successful stormwater infiltration facilities along Minnesota roadways.
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Edina Studies Snowmelt To Reduce Chlorides From Deicing Operations
In Minnesota’s metro region, areas of shallow groundwater show increasing evidence of chloride contamination from winter road maintenance operations, particularly deicing. More than a quarter show chloride concentrations at the maximum contaminant level for municipal drinking water. In addition, 123 lakes and rivers show chloride impairment or risk of impairment for aquatic life. Chlorides are now considered the second most important threat, after phosphorus, to Minnesota’s urban waters.
The City of Edina, with funding from the Local Road Research Board, hired the University of Minnesota to analyze chloride accumulation in city snowmelt following winter maintenance operations to learn how to most effectively adjust its deicing strategies to reduce chloride contamination.
Over two winters, researchers collected data from city deicing operations and correlated it with chlorides present in meltwater runoff. A sampler box collected data continuously, and snow pile cores were also analyzed. Snowplow operators then examined the results during workshops, yielding innovative ideas for reducing salt use.
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A Long-Term Approach to Green Stormwater Infrastructure
This article was originally published in Catalyst, May 2021.
Strategies for managing stormwater runoff have been steadily undergoing a shift in recent decades toward “green” infrastructure. This is a potentially beneficial change, but transportation professionals are beginning to recognize a need for better information on how to properly design, implement, and maintain these facilities.
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Crossroads 