Stormwater Discharges from Transportation Sources
Streets, roads, and highways are the primary mode for moving goods, people, and services but also can carry stormwater runoff pollutants from the adjacent land and from cars, trucks, and buses, including heavy metals from tires, brakes, and engine wear, and hydrocarbons from lubricating fluids. If the pollutants are not properly controlled, they can impair waters causing them to no longer support the water's designated uses and biotic communities.
Similar to traditional stormwater management authorities (cities and counties), transportation authorities are also responsible for managing the stormwater runoff that discharges to our nation's waters via regulated municipal separate storm sewer systems (MS4s) along streets, roads, and highways, but there are some key differences:
Transportation MS4s versus Traditional MS4s
(NonTraditional) Transportation MS4
(Traditional) City/County MS4
State transportation agencies often own streets and highways that can stretch for many miles, and cross numerous waterways, watersheds, and jurisdictions
Local governments are typically responsible for streets they own, which are usually in a limited geographical area
Population served by MS4
State transportation agencies often serve a transient population of drivers and passengers
Local governments often serve residents and businesses in their community boundaries
State transportation agencies have little to no enforcement authority to implement ordinances and must use other mechanisms
Local government can develop and implement ordinances that they then enforce in their community boundaries
An integrated approach is needed to address these challenges and strengthen stormwater management programs (SWMPs). This site provides access to transportation-specific stormwater information primarily for state transportation agencies, but county and local transportation authorities will also find it useful.
Regulations, Permits, and Programs
The NPDES program requires operators of regulated transportation MS4s to reduce the discharge of pollutants from their MS4 to the maximum extent practicable. They must each establish a comprehensive SWMP under their NPDES permit. Most states are authorized to administer their own stormwater permitting programs. EPA remains the permitting authority in New Hampshire, Massachusetts, New Mexico, Idaho, territories, and on most Indian Country lands.
- Municipal MS4s —Find information on the municipal stormwater program in guides and fact sheets.
- Authorization Status— Determine your permitting authority for construction and industrial stormwater discharges.
- Stormwater and TMDLs —Learn about how TMDLs are developed and read case studies.
A permitted Phase II MS4’s SWMP must at least cover:
- Public education/outreach,
- Public involvement,
- Pollution prevention/good housekeeping,
- Post-construction, and
- Illicit discharge detection and elimination.
State Department of Transportation (DOT) Information
Many state departments of transportation (DOTs) maintain a stormwater website where they post their NPDES permit, program-related information, and specific actions they are taking to reduce stormwater pollution.
Visit the following non-EPA websites to learn more about how state DOTs are managing stormwater runoff The following links exit the site Exit.
Other Federal Websites
- Federal Highway Administration (FHWA)— Reports and guidance for transportation departments to better control stormwater along highways.
- U.S. Geological Survey (USGS) —An overview of stormwater, common concerns, publications, and other useful information.
State DOT Stormwater Websites
- Alabama DOT (ALDOT)
- Alaska DOT & Public Facilities Resources (Alaska DOT&PF)
- Arkansas DOT (Arkansas State Highway and Transportation Department – AHTD)
- Arizona DOT (ADOT)
- California DOT (Caltrans)
- Colorado DOT (CDOT)
- Connecticut DOT (ConnDOT)
- Delaware DOT (DelDOT)
- Hawaii DOT (HDOT)
- Indiana DOT (INDOT)
- Florida DOT (FDOT)
- Illinois DOT (IDOT)
- Kansas DOT (KDOT)
- Louisiana DOT (Louisiana Department of Transportation and Development - DOTD)
- Michigan DOT (MDOT)
- Minnesota DOT (MnDOT)
- Mississippi DOT (MDOT)
- Missouri DOT (MoDOT)
- Montana DOT (MDT)
- Nebraska DOT (NDOR)
- Nevada DOT (NDOT)
- New York State DOT (NYSDOT)
- North Carolina DOT (NCDOT)
- North Dakota DOT (NDDOT)
- Ohio DOT (ODOT)
- Oregon DOT (ODOT)
- Pennsylvania DOT (PennDOT)
- Rhode Island DOT (RIDOT)
- South Carolina DOT (SCDOT)
- South Dakota DOT (SDDOT)
- Tennessee DOT (TDOT)
- Texas DOT (TxDOT)
- Utah DOT (UDOT)
- Vermont DOT (VTrans)
- Virginia DOT (VDOT)
- Washington State DOT (WSDOT)
- West Virginia DOT (WVDOT)
- Wisconsin DOT (WisDOT)
Innovative Materials and Good Practices
- public education,
- public involvement,
- illicit discharge detection and elimination, and
- good housekeeping.
Other manuals are specific to a particular region, but they still might provide innovative tools from which all transportation authorities can benefit.
- Copper-free Brake Initiative —EPA, the Environmental Council of the States (ECOS), and eight automotive industry groups, signed an agreement to reduce the use of copper and other materials in motor vehicle brake pads. This initiative will decrease runoff of those materials from roads into the nation’s streams, rivers, and lakes and is a national example of pollution prevention/source control.
- Green Streets, Green Jobs, Green Towns InitiativeExit— This partnership aims to stimulate the green jobs market and enable families to work where they live and play. Small-to-mid-sized communities can boost their local economies and protect water resources through the use of watershed planning, and design and construction of stormwater best management practices (BMPs).
- Greening America’s Capitals— This EPA program helps state capitals develop an implementable vision of environmentally friendly neighborhoods that incorporate innovative green infrastructure strategies. Through the Partnership for Sustainable Communities, EPA provides design assistance to sustainable communities that protect the environment, economy, and public health and to inspire state leaders to expand the program.
- Maryland State Highway Administration (MDSHA) Exit —MDSHA’s construction program provides statewide oversight, sets policy, and supports and contributes to building a safe highway system to enhance Maryland’s communities and economy, and the environment.
- Washington DOT Construction Manual Exit —In coordination with FHWA, the WSDOT State Construction Office coordinates the development of policies and standards to provide guidance and oversight on construction issues.
Illicit Discharge Detection and Elimination
- Ohio DOT Outfall Inventory Manual and Database —Ohio DOT’s database contains 6,826 outfalls from over 1,900 miles of roadway with specific attributes.
- Colorado Department of Transportation’s Illicit Discharge Program —Colorado DOT’s example of a web page set up for reporting illicit discharges.
Maintenance of BMPs
- Caltrans BMP Field Manual Troubleshooting Guide — Guidance for installing, inspecting, and maintenance of construction.
Pollution Prevention and Good Housekeeping
- Environmental Stewardship Practices, Procedures, and Policies for Highway Construction and Maintenance —This compilation of state transportation manuals, procedures, and practitioners can be used as a guide for good stewardship practices.
- Litter on State Highways —Washington State Department of Transportation’s Web page on litter that quantifies the amount of litter picked up, the associated costs, and their Adopt-A-Highway program.
- Green Infrastructure – Learn more about green infrastructure techniques that uses vegetation, soils, and natural processes to manage water and create healthier urban environments.
- Nonpoint Source Program— Learn about nonpoint source pollution programs in your area and what you can do to protect and conserve valuable ecosystems.
- OWOW Green Street Page —Green Streets are a sustainable stormwater management strategy that contributes to community redevelopment. Many cities have replaced traditional street rehabilitation with green street strategies to address stormwater, transportation, and neighborhood stabilization goals. By combining transportation choice with environmental strategies, a green street product can support redevelopment efforts from multiple stakeholder perspectives.
- Green Streets: A Conceptual Guide To Effective Green Streets Design Solutions
- Managing Wet Weather with Green Infrastructure — Municipal Handbook on Green Streets
- Stormwater to Street Trees: Engineering Urban Forests for Stormwater Management —This guide can help engineers, planners, developers, architects, arborists, and public officials understand how trees perform and interact in a stormwater management system, and the new technologies that are being used to increase the stormwater utility function of the urban forest, even in the densest urban environments.
The following links exit the site Exit
- Arizona DOT Post-Construction Best Management Practices (BMP) Manual
- District DOT Green Infrastructure Standards — These green infrastructure standards are required in all DDOT contracts and include drawings, requirements, and procedures.
- Minnesota Stormwater Manual — Examples of post-construction practices.
- Washington State DOT Highway Runoff Manual — Guidance for designing stormwater systems for transportation projects.
- Permeable Interlocking Concrete Pavement (PICP) Fact Sheet (PDF)(4 pp, 5.18 MB, About PDF) —Benefits and application opportunities with PICP.
- Ultra Urban BMPs —View BMP fact sheets, a FHWA Report, and BMP monitoring studies of stormwater management in an ultra-urban environment.
- Chicago Green Alley Handbook — BMP techniques in green alley designs and flood control.
Public Education and Public Participation
- Michigan DOT Stormwater Education Program Exit —Examples of stormwater outreach materials.
- North Carolina DOT Highway Stormwater Program, External Education Program Exit — Rest areas can be used as an educational opportunity to post pet stations and education displays.
Television Advertisement and Radio
- Don’t mess with Texas Exit —This campaign emphasizes the importance of preventing road litter.
- Don’t Trash California Exit—Caltrans provides examples of advertising for public outreach.
- Washington State DOT Stormwater Monitoring Program — Describes the SWMP that is included in WSDOT’s draft permit.
- Caltrans Comprehensive Protocols Guidance Manual (PDF)(667 pp, 5.01 MB, About PDF) —This manual includes monitoring protocols for stormwater quality.
Research, Tools, and Webcasts
Research is an important component in stormwater management. Research can update us on the most recent technologies, improved strategies, cost-effective data, or emerging issues that need to be addressed. Many of the resource listed on this page are specific to stormwater and transportation.
Long-Term Stormwater Planning
- - Guide to assist states and local governments in developing and implementing effective long-term stormwater plans. This document describes how to develop a comprehensive long-term community stormwater plan that integrates stormwater management with communities' broader plans for economic development, infrastructure investment and environmental compliance.
- Joint EPA-Federal Highway Administration (FHWA) Webcasts (Coming Soon) —This page provides links to webinars cohosted by EPA and FHWA that feature techniques that state and local transportation departments have implemented in their SWMPs to reduce the discharge of stormwater pollutants.
- Research—Information on EPA developments and related resources for those who want to know more about stormwater-related green infrastructure practices.
- Experimental Permeable Pavement Parking Lot and Rain Garden for Stormwater Management—Information on EPA’s green infrastructure research on long-term porous pavement to address stormwater management issues.
- National Cooperative Highway Research Program Exit —This program under the Transportation Research Board addresses issues state transportation departments suggest to find solutions. The research conducted also can provide useful information to local transportation departments and others.
- Eco-Logical Approach Exit —This approach organizes current methods to identify natural resources and avoid, minimize, and mitigate impacts in a systematic, stepwise process. It was developed by a steering team consisting of representatives of federal agencies.
- Green Highways Partnership (GHP) Exit —The GHP is a voluntary public-private partnership that advances environmental stewardship in transportation planning, design, construction, operations, and maintenance.
- Watershed Resources Registry Exit—This interactive mapping tool can provide a framework and be tailored to characterize and prioritize natural resource management opportunities using a watershed approach. Preserving and/or restoring natural hydrology for stormwater is one element along with restoration and/or preservation of riparian zones, wetlands, and uplands.
- Stochastic Empirical Loading and Dilution Model (SELDM) Exit — SELDM is a stormwater-quality runoff model for highways and other land uses that estimates stormwater flows, pollutant loads, and concentrations from roads and upstream watersheds. The USGS developed SELDM in cooperation with the FHWA.
- Green Infrastructure — This page provides links to EPA and non-EPA Web pages that can provide information on how green infrastructure can be used to help mitigate climate change impacts.
- Context Sensitive Solutions -- Context Sensitive Solutions (CSS) is a collaborative, interdisciplinary approach that involves all stakeholders and leads to preserving and enhancing environmental resources along with other resources, while improving or maintaining safety, mobility, and infrastructure conditions.
- Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities —The report by the Institute for Transportation Engineers (ITE) can be used as a guide for roadway improvement projects.
- Caltrans Comprehensive Protocols Guidance Manual Exit —Caltrans has developed a number of monitoring, research, and applied studies.
- Washington State Department of Transportation Stormwater Monitoring Exit—This page describes the sort of monitoring being done, guidance documents, and summary reports.
Selecting Best Management Practices
- Caltrans BMP Retrofit Pilot Program Exit —This report discusses performance evaluation and cost of structural BMPs for treating stormwater runoff from Caltrans facilities.
- Evaluation of BMPs for Highway Runoff Control Exit —This guide is from the National Cooperative Highway Research Program (NCHRP) for selecting BMPs for highway runoff control.
- Stormwater Best Management Practices in an Ultra-Urban Setting:Exit Selection and Monitoring —Ultra-urban areas have high densities of paved surfaces. Buildings, parking facilities, urban streets, highways, or walkways cover a majority of the land area, with imperviousness typically greater than 50 percent in ultra-urban areas, and up to 100 percent in some cases.
- Stormwater Quality Benefits of a Porous Asphalt Overlay —This study documents the impacts of porous asphalt overlay to the quality of highway stormwater runoff.
- Tennessee State DOT Post-Construction Stormwater BMP Research Report —This report, written for the Tennessee Department of Transportation, includes research on other Department of Transportation post-construction stormwater activities, how other Departments of Transportation are handling post-construction stormwater from highway and facility sites, and a literature review of post-construction BMPs.
- Preliminary Environmental Investigation of Heavy Metals in Highway Runoff —This report discusses the research done by the Civil and Environmental Engineering Department at Washington State University for Washington State Department of Transportation.
Case Studies and Projects
With the challenges of climate change, impaired waters, and population and development growth, transportation entities are thinking beyond the right-of-way and approaching stormwater on a broader, watershed scale. New development and redevelopment projects are not only altering or creating new conveyance systems, but also incorporating effective stormwater BMPs—including green infrastructure and green street techniques—to reduce stormwater flow. Creating pervious biking/walking paths and curbside vegetation (e.g., bioretention areas) are just two of the many ways to incorporate these techniques.
- Construction and Maintence Practices for Permeable Friction Courses (PDF)(133 pp, 4.52 MB, About PDF) Exit— These overlays are a layer of pervious material on top of an impervious layer. This practice has been shown to have multiple environmental and safety benefits.
- Compost Use on State Highway Applications: Current Compost Usage by State DOTs — This report provides benefits, tools, and state DOT case studies of compost being used for roadside applications.
- Strategies to Mitigate the Impacts of Chloride Roadway Deicers on the Natural Environment (108 pp, 3 K, About PDF) Exit-- A synthesis of strategies used by tranportation agencies to mitigate environmental harm from chlorides in deicing agents.
Local Roads and Streets
- Complete Streets —Learn how transportation agencies are instituting complete streets policies, providing a more balanced transportation infrastructure resulting in reduced vehicle-related pollutants, and providing opportunities for improved stormwater management.
- Greening DC Streets —Washington, DC Department of Transportation is implementing a model green streets for the District of Columbia.
- Street Reconstruction with Pervious Pavers in Westmoreland Neighborhood of portland, Oregon —This project as part of Portland Green Streets uses a variety of pavement materials to show how the materials manage stormwater and maintain as a street surface.
- Green Streets: A Conceptual Guide to Effective Green Streets Design Solutions —This guide for green street designs shows that they provide better environmental performance for residential, commercial, arterial streets, and alleys.
- Green Streets —This web page provides a link to the Municipal Handbook for managing wet weather with green infrastructure/green streets and additional links on its home page for more information.
- The Chicago Green Alley Handbook —The Chicago Department of Transportation is working on a green streets pilot project to construct and measure the performance of a complete street/green street infrastructure.
Shared Use Paths
- Springwater on the Willamette Trail Exit —This bike trail in Portland, Oregon, was constructed from porous asphalt to capture stormwater.
- Connections - The National Transportation Enhancement Clearinghouse Newsletter —The beautification of 92nd Avenue in Portland, Oregon, included the construction of a sidewalk, a bike lane, lighting, and stormwater quality and detention swales.
- Coastal Stormwater BMPs Exit —North Carolina Department of Transportation works with Kure Beach to reduce stormwater using a dune infiltration system.
- Stormwater Curb Extension —The Portland Bureau of Transportation retrofitted a residential collector into a vegetative curb extension. This project incorporates a ramp for pedestrian use and captures, treats, and infiltrates runoff.
- Stormwater Planters —As part of Portland Green Street projects, a series of stormwater planters are structured so that intense storm events can be captured while maintaining pedestrian circulation and street parking.