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Environmental Review Toolkit


Wetlands, coastlines, and water quality are vital parts of the natural ecosystem and require careful planning to avoid, minimize, and compensate unavoidable impacts as a result of transportation projects. FHWA provides information and guidance to Federal, State, and local agencies to assess the function of these resources and restore the integrity of the Nation’s aquatic ecosystems.

For information related to specific Legislation, Regulation, and Guidance related to water resources, please visit the Natural Environment Legislation page.

Wetlands and Watershed

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A watershed is an area defined by a common drainage endpoint. Land uses within each watershed directly affect their water quality and other environmental features. As a significant form of land use, transportation presents many potential threats to watersheds.

The United States Environmental Protection Agency (EPA) provides resources on protecting watersheds and other water sources, including the Surf Your Watershed tool that provides lists of organizations working to protect local watersheds nationwide.

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Wetlands are delicate natural resources that serve many functions. Not only do they provide habitat for aquatic species, but they also improve water quality and manage floodwaters.

The FHWA offers the following resources for minimizing and mitigating the impacts from transportation projects on wetlands:

5 Star Wetland and Urban Waters Restoration Grants - This program brings together students, conservation corps, other youth groups, citizen groups, corporations, landowners and government agencies to provide environmental education and training through projects that restore wetlands and streams. The program provides challenge grants, technical support and opportunities for information exchange to enable community-based restoration projects. Funding levels are modest, from $10,000 to $40,000, with $20,000 as the average amount awarded per project.

Results of the FHWA Domestic Scan of Successful Wetland Mitigation Programs, 2005 - Managing and mitigating wetlands impacts due to highway projects is a significant issue for FHWA and State DOTs. To help find out what kind of issues were most problematic, and to identify successful solutions that were being used, the Office of Environment and Planning conducted an interagency scan of wetland mitigation and impact management practices in eight States. There was a strong focus on mitigation banking, including what issues and solutions have been associated with the development of successful, workable wetland mitigation banks. Where banks were not being used, successful on-site mitigation projects were examined.

Executive Orders

Subject/Title Resource URL E.O. Number
Executive Order 12962 on Recreational Fisheries Executive Order 12962
Amendments to Executive Order 12962 Executive Order 12962
Executive Order 11988 on Floodplain Management Executive Order 11988
Executive Order 11990 on Protection of Wetlands Executive Order 11990


FHWA offers the following instructional recording on wetlands:

RIBITS Wetland Mitigation Tool - Live Demonstration
FHWA and the U.S. Army Corps of Engineers (USACE) have produced an instructional recording for transportation users on how to use the Army Corps Regulatory In lieu fee and Bank Information Tracking System (RIBITS) to find mitigation credits for transportation projects. A version of this training was presented as a webinar in December of 2013. RIBITS is a web site that provides information on stream and wetland mitigation banks and in-lieu fee programs across the country. Users can access a wide range of information on wetland mitigation and endangered species conservation banks including the availability of mitigation credits, bank ledgers, service areas, and national and local policies and practices for the use of mitigation and conservation banks. Viewers of this demonstration will learn about:

  • Using RIBITS (Regulatory In lieu fee and Bank Information Tracking System) to determine if you can purchase mitigation credits for your transportation project.
  • Documentation for these mitigation banking or in-lieu fee programs.
  • New RIBITS features for transportation professionals.

The recording can be accessed at:

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Subject/Title Resource URL Agency
Association of State Wetland Managers Website N/A
Chesapeake Bay Watershed Program Webpage USFWS
Clean Water Action Plan: Wetlands Webpage EPA
Natural Resources Conservation Service: Wetlands Webpage USDA
Section 404 Compensatory Mitigation Webpage EPA
Society of Wetland Scientists Website N/A
Wetlands Research Technology Center Website USACE

Stormwater Management and Water Quality

When precipitation occurs over highways and other impervious surfaces, the resulting stormwater can carry debris, sediment, and chemicals into water sources, diminishing their quality. In addition to the stormwater runoff that carries sediment and pollutants into water sources, highway construction and maintenance activities have potential to affect nearby bodies of water.

The FHWA provides the following reports and guidance for controlling stormwater runoff along highways and minimizing the effects of transportation projects on water quality:

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  • Granato, G.E., 2021, Highway-Runoff Database (HRDB) Version 1.1.0b in Granato, G.E., and Friesz, P.J., 2021, Model archive for analysis of long-term annual yields of highway and urban runoff in selected areas of California with the Stochastic Empirical Loading and Dilution Model (SELDM): U.S. Geological Survey data release
  • Granato, G.E., 2021, Stochastic Empirical Loading and Dilution Model (SELDM) software archive: U.S. Geological Survey software release
  • Granato, G.E., Spaetzel, A.B., and Medalie, L., 2021, Statistical methods for simulating structural stormwater runoff best management practices (BMPs) with the Stochastic Empirical Loading and Dilution Model (SELDM): U.S. Geological Survey Scientific Investigations Report 2020–5136, 41 p.
  • Granato, G.E., and Jones, S.C., 2019, Simulating Runoff Quality with the Highway Runoff Database (HRDB) and the Stochastic Empirical Loading and Dilution Model (SELDM): Transportation Research Record, Journal of the Transportation Research Board, 7 p. - The purpose of this paper is to describe the datasets that are available in version 1.1 of the HRDB and to demonstrate how data and statistics from the HRDB can be used with SELDM to assess highway-runoff quality. As such, this paper describes the practice-ready data and methods that can be used by DOTs to assess, and if necessary, mitigate the effects of highway runoff on receiving waters. Version 1.1 of the HRDB includes more data-quality information than version 1.0 and an option to calculate highway-runoff statistics for multiple sites in batch mode. However, the differences that are apparent to the user are trivial and are explained within the HRDB graphical user interface, so these changes are not described here.
  • Granato, G.E., and Jones, S.C., 2017, Estimating Total Maximum Daily Loads with the Stochastic Empirical Loading and Dilution Model: Transportation Research Record, Journal of the Transportation Research Board, No. 2638, p. 104-112. - The Massachusetts Department of Transportation (DOT) and the Rhode Island DOT are assessing and addressing roadway contributions to total maximum daily loads (TMDLs). Example analyses for total nitrogen, total phosphorus, suspended sediment, and total zinc in highway runoff were done by the U.S. Geological Survey in cooperation with FHWA to simulate long-term annual loads for TMDL analyses with the stochastic empirical loading and dilution model known as SELDM. Concentration statistics from 19 highway runoff monitoring sites in Massachusetts were used with precipitation statistics from 11 long-term monitoring sites to simulate long-term pavement yields (loads per unit area). Highway sites were stratified by traffic volume or surrounding land use to calculate concentration statistics for rural roads, low-volume highways, high-volume highways, and ultraurban highways. The median of the event mean concentration statistics in each traffic volume category was used to simulate annual yields from pavement for a 29- or 30-year period. Long-term average yields for total nitrogen, phosphorus, and zinc from rural roads are lower than yields from the other categories, but yields of sediment are higher than for the low-volume highways. The average yields of the selected water quality constituents from high-volume highways are 1.35 to 2.52 times the associated yields from low-volume highways. The average yields of the selected constituents from ultraurban highways are 1.52 to 3.46 times the associated yields from high-volume highways. Example simulations indicate that both concentration reduction and flow reduction by structural best management practices are crucial for reducing runoff yields.
  • Granato, G.E., DeSimone, L.A., Barbaro, J.R., and Jeznach, L.C., 2015, Methods for evaluating potential sources of chloride in surface waters and groundwaters of the conterminous United States: U.S. Geological Survey Open-File Report 2015–1080, 89 p.
  • Remotely Monitoring Water Quality Near Highways - A Sustainable Solution, 2015 - Collecting water quality data on streams located near highways can be challenging in remote and difficult-to-reach locations. Obtaining and transporting water samples is time-consuming, expensive, and sometimes dangerous. Another key challenge is that transportation agencies can miss the release of toxins and pollutants that occur in a short time period or the first flush of stormwater runoff from highways. Collecting water quality data is crucial, however, to State departments of transportation in their effort to meet U.S. Environmental Protection Agency National Pollutant Discharge Elimination System permit requirements, particularly during the first flushes of spring stormwater runoff.

    Placing sensors directly in the water to collect data is an appealing solution, but these in situ sensors typically rely on batteries that have to be replaced as often as every 3 weeks. Designing a renewable and self-sustaining onsite system is the goal of the Exploratory Advanced Research (EAR) Program project, “A Remote, Self-Sustained System for Monitoring Water Quality Near Highways.” Montana State University conducted this research, which was funded by the Federal Highway Administration (FHWA).

  • Determining the State of the Practice in Data Collection and Performance Measurement of Stormwater Best Management Practices, 2014 - The objective of this research project is to assess the state of practice of data collection and performance measurement in stormwater management programs at state Departments of Transportation (DOTs). Specifically, this study evaluates if it is feasible to develop performance measures for stormwater that state DOTs can use in performance-based planning and programming. The study focused on both construction-phase as well as post-construction application of BMPs to protect water quality.
  • Granato, G.E., 2013, Stochastic empirical loading and dilution model (SELDM) version 1.0.0: U.S. Geological Survey Techniques and Methods, book 4, chap. C3, 112 p., CD–ROM.
  • Stormwater Best Management Practices (BMPs) in an Ultra-Urban Setting: Selection and Monitoring, 1997 - The purpose of this report is to provide a planning-level review of the applicability and use of new and more traditional BMPs in ultra-urban areas. This report focuses on the unique characteristics specific to ultra-urban settings and provides specific guidance for selecting and siting stormwater management technologies. The information is structured in an informative, user friendly format, with case studies highlighting examples of BMP monitoring throughout the country and tables illustrating the characteristics of each BMP to facilitate comparison and identification of specific technologies appropriate to a given site. BMP information is provided in fact sheets, which address applicability, effectiveness, siting and design, maintenance, and cost considerations. The report is organized into separate chapters that address ultra-urban considerations, BMP design information tailored to the ultra-urban environment, monitoring program design, and BMP selection.
  • Bank, F.G., Cazenas P.A., Cutshall, C.D., Granato, G.E., Iyer B., Jongedyk, H., Palumbo, V.J., Prendergast G., Salter, J., Storey B., Young, G.K., 1997, Water Quality and Hydrology: in Environmental Research Needs in Transportation, Transportation Research Circular 469, Transportation Research Board, National Research Council, Washington D.C. p. 73-80.
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  • Stochastic Empirical Loading Dilution Model (SELDM), 2013 - The USGS, in cooperation with the FHWA, developed the Stochastic Empirical Loading and Dilution Model (SELDM) to replace the FHWA runoff-quality model developed in the 1980s and published in 1990. That model was limited to a few water-quality constituents, was based on the assumption that upstream concentrations are equal to zero, was based on water quality standards from the 1980’s, was not compatible with newer operating systems, and there was no mechanism for continuing model support. SELDM is designed as a tool that can be used to transform disparate and complex scientific data into meaningful information about the risk for adverse effects of runoff on receiving waters, the potential need for mitigation measures, and the potential effectiveness of such management measures for reducing these risks. SELDM is designed to help develop planning-level estimates of event mean concentrations, flows and loads from a highway site and an upstream or lake basin. The model has been tested by the FHWA, many State DOTs, the EPA, and several other regulatory agencies. This resulted in a robust model that will be acceptable to DOTs, regulators, and resource-management agencies.
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  • The International Stormwater Best Management Practices (BMP) Database project website features a database of over 600 BMP studies, performance analysis results, tools for use in BMP performance studies, monitoring guidance and other study-related publications.
  • Stormwater Discharges from Transportation Sources - 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.
  • TRB Publications about Environment - The Transportation Review Board maintains an updated list of publications related to transportation and the environment.
  • Evaluation of Best Management Practices for Highway Runoff Control, 2006 - This report focuses on improving the scientific and technical knowledge base for the selection of best management practices (BMPs) through a better understanding of BMP performance and application. This report documents an extensive program of research on the characterization of BMPs and stormwater, and the influence of factors such as land use practice, hydraulic characteristics, regional factors, and performance evaluation. The report includes a CD containing a spreadsheet model and three additional volumes: User’s Guide for BMP/LID Selection, Appendices to the User’s Guide, and Low Impact Development Design Manual for Highway Runoff Control.
Subject/Title Resource URL Agency
Erosion and Sediment Control on Highway Construction Projects (23 CFR 650B) Regulation FHWA
Erosion and Sediment Control on Highway Construction Projects (NS 23 CFR 650B) Guidance FHWA
Guidance on 23 U.S.C. §328 Environmental Restoration and Pollution Abatement Memorandum FHWA


FHWA’s regulations, policies, and guidance implement national floodplain goals and requirements while keeping public safety paramount and balancing flood risks, environmental stewardship, and cost in the planning, design, construction, and operations/maintenance of transportation infrastructure.

Executive Order 11988 “Floodplain Management” is available here.

FHWA EO 11988 implementation procedures are located at 23 CFR 650 subpart A.

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Subject/Title Resource URL Agency
23 CFR 650 Subpart A - Location and Hydraulic Design of Encroachments on Flood Plains Regulation FHWA
Environmental Impact and Related Procedures - Programmatic Agreements and Additional Categorical Exclusions Final Rule FHWA and FTA
Highways in the River Environment - Floodplains, Extreme Events, Risk, and Resilience Technical Report FHWA
International Erosion Control Association (IECA) Website IECA
Association of State Floodplain Managers Website ASFPM
Mapping Service Center Website FEMA
Significant Encroachments Memorandum FHWA
Procedures for Coordinating Highway Encroachments on Floodplains with FEMA Memorandum FHWA
Floodplain Management and Protection DOT Order 5650.2 DOT
Guidance for Implementing the One-Foot Standard for Encroachments on NFIP Floodplains Guidance FHWA

Coastal Zone Management

The Coastal Zone Management Act, administered by the National Oceanic and Atmospheric Administration (NOAA), provides for the management of the nation’s coastal resources and includes programs such as the National Coastal Zone Management Program. This program is a partnership between coastal States and territories and the Federal government. The FHWA coordinates with the State Coastal Zone Management agency or appropriate local agencies when a proposed action is within, or is likely to affect land or water uses within, the area covered by a State Coastal Zone Management Program approved by the Department of Commerce.