Reducing the Environmental Impact of Road Construction

Construction of roads and buildings can generate significant amounts of sediment and turbid runoff while the construction process is underway. As a result, the sites are required to have plans to control erosion and sediment through the use of best management practices (BMPs) such as sediment basins, silt fences, check dams, and many others. While the original intent of the Clean Water Act of 1972 was to require basic erosion and sediment control, these practices have been improved and refined to retain most of the sediment generated on site. This has been particularly evident on NCDOT projects, which have added and improved practices continuously for many years. While current practices largely eliminate discharges of heavy sediment, turbidity caused by fine sediment that doesn’t settle easily remains a problem in construction site discharges. The can be addressed through various systems to introduce polyacrylamide (PAM) into the stormwater, the potential reduction in turbidity is often not achieved. This project will track turbid discharges on active construction sites and determine the sources and potential remedies to the problem. The goal will be to evaluate current practices in the field and test modifications and additions which can provide better turbidity reduction. Particular attention will be focused on construction in the Swift Creek watershed, as there is a population of endangered mussels in that creek. Because of increased concern and interest in pollinator populations, there is also interest in creating areas which have plants that provide food and habitat for these insects. Wildflowers are of particular interest as they provide multiple environmental benefits. There is potential for them to be used as ground covers on new construction areas, where bare subsoils are expos​​ed on slopes which need to be vegetated to stabilize them and prevent erosion. There is a great deal of knowledge about establishing and maintaining grass in roadside environments, but much less about doing that with wildflowers. This project will evaluate mixtures of different pollinator-friendly wildflower species and potential nurse crops for plant establishment and flowering. In addition, factors in establishment such as soil amendments, seeding method, and mulches will be tested to help determine the best approaches to establishing wildflowers on low-maintenance areas.

Language

• English

Project

• Status: Active
• Funding: $408444
• Contract Numbers:

  FHWA/NC/2020-01

• Sponsor Organizations:

  North Carolina Department of Transportation

  Research and Development
  1549 Mail Service Center
  Raleigh, NC  United States  27699-1549
• Managing Organizations:

  North Carolina Department of Transportation

  Research and Development
  1549 Mail Service Center
  Raleigh, NC  United States  27699-1549
• Project Managers:

  Kirby, John

• Performing Organizations:

  North Carolina State University, Raleigh

  College of Agriculture and Life Sciences
  Department of Soil Sciences, Campus Box 7619
  Raleigh, NC  United States  27695-7619
• Principal Investigators:

  McLaughlin, Richard

• Start Date: 20190801
• Expected Completion Date: 20220731
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Environmental impacts; Erosion control; Road construction; Sediment discharge; State of the practice; Turbidity; Watersheds; Wildflowers
• Geographic Terms: North Carolina
• Subject Areas: Construction; Environment; Highways;

Filing Info

• Accession Number: 01715958
• Record Type: Research project
• Source Agency: North Carolina Department of Transportation
• Contract Numbers: FHWA/NC/2020-01
• Files: RIP, STATEDOT
• Created Date: Sep 10 2019 3:14PM