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Mid-America Transportation Center

NDOR Development and Evaluation of BMP's for Highway Runoff Pollution Control


Researchers

  • Principal Investigator: Tian Zhang (tzhang1@unl.edu 402-554-3784)
  • Co-Principal Investigator: Massoum Moussavi (mmousavi2@unl.edu (402)554-3414)
  • Project Status
    In Progress
    About this Project
    Brief Project Description & Background
    To prevent harmful pollutants from being washed or dumped into a Municipal Separate Storm Sewer Systems (MS4s), operators must obtain a National Pollutant Discharge Elimination System (NPDES) permit and develop a stormwater management program. Currently, many municipalities and non-traditional MS4s are under federal regulations that require new developments or redevelopments of a certain size to capture (and treat) the first half-inch of runoff from all new impervious surfaces (roofs, driveways, sidewalks, and so forth) onsite, instead of allowing it to run into the sewers or nearby waterways. Development of Best Management Practices (BMPs) to manage and treat stormwater before it arrives at storm sewer systems is a new challenge to these entities. Currently the mandate from Environmental Protection Agency (EPA) does not include specific pollutants to be removed or levels that must be obtained for stormwater. However it is widely anticipated that the requirement to obtain specific levels of treatment (i.e. 80% removal of Total Suspended Solids), will soon be enforced. As a part of the NPDES permit the Roadside Stabilization Unit and Roadway Design-Hydrology are creating the Post Construction Stormwater Program, which establishes the framework for the implementation of stormwater treatment Best Management Practices (BMPs) on projects within an MS4 boundary. Many of these BMPs have never been implemented or tested by the Nebraska Department of Roads (NDOR). Having information regarding the effectiveness of BMP options will give NDOR the tools to design for these requirements when the time comes. Therefore, it is important to develop and evaluate these BMPs to find the best systems for Nebraska’s environmental conditions and soils. It is important that stormwater BMPs are cost-effective and require minimal maintenance. This research is focused on those BMPs that rely on biorentention, infiltration, and slow conveyance of stormwater.
    Research Objective
    The objective of this research is to develop and evaluate available BMPs to find the best systems for Nebraska’s environmental conditions and soils.
    Potential Benefits
    This project anticipates new requirements that will soon be released and will help provide information to NDOR to be prepared to meet these requirements for stormwater treatment.
    Abstract
    Polluted stormwater runoff is commonly transported through Municipal Separate Storm Sewer Systems (MS4s), from which it is often discharged untreated into local waterbodies. To prevent harmful pollutants from being washed or dumped into an MS4, operators must obtain a National Pollutant Discharge Elimination System (NPDES) permit and develop a stormwater management program. Currently, many municipalities and non-traditional MS4s are under federal regulations that require new developments or redevelopments of a certain size to capture (and treat) the first half-inch of runoff from all new impervious surfaces (roofs, driveways, sidewalks, and so forth) onsite, instead of allowing it to run into the sewers or nearby waterways. Development of Best Management Practices (BMPs) to manage and treat stormwater before it arrives at storm sewer systems is a new challenge to these entities. Currently the mandate from Environmental Protection Agency (EPA) does not include specific pollutants to be removed or levels that must be obtained for stormwater. However it is widely anticipated that the requirement to obtain specific levels of treatment (i.e. 80% removal of Total Suspended Solids), will soon be enforced. As a part of NPDES permit the Roadside Stabilization Unit and Roadway Design-Hydrology are creating the Post Construction Stormwater Program, which establishes the framework for the implementation of stormwater treatment Best Management Practices (BMPs) on projects within an MS4 boundary. These BMPs will be designed to treat the first 0.5” Water Quality Volume (WQV), and will be permanent measures on a project site. Many of these BMPs have never been implemented or tested by the Nebraska Department of Roads (NDOR). Having information regarding the effectiveness of BMP options will give NDOR the tools to design for these requirements when the time comes. Therefore, it is important to develop and evaluate these BMPs to find the best systems for Nebraska’s environmental conditions and soils. It is important that stormwater BMPs are cost-effective and require minimal maintenance. This research is focused on those BMPs that rely on biorentention, infiltration, and slow conveyance of stormwater. Many of these BMPs rely on engineered soil media with high percolation rates to be effective; several challenges related to these BMPs exist: (1) Usually, BMPs such as subsurface constructed wetlands (CWs) and bioretention bed sequences (BRS) need a 2–3 foot thick layer of porous media; the conventional media (e.g., gravel or crushed rock) are expensive due to their high density. Finding a medium that has a low density, a long lifespan, and can recover its original volume after compression (e.g., due to car accidents or maintenance activities) is critical. (2) When a soil medium is used in these BMPs, creating a soil medium that drains at a desired rate is functionally attainable. However, the combinations of plants and media that will be sustainable in the varied regions of Nebraska are unknown. Certain plant species have been shown to provide significant uptake of pollutants in a process called phytoremediation. This uptake is not universal for all species and all pollutants, so knowing the key species to use in a BMP could drastically improve its effectiveness.
    Project Amount
    $ 113,918