Determining if your project will affect "Waters of the U.S."

"Navigable Waters of the U.S." includes all surface water bodies such as drainage ditches, intermittent streams, streams, lakes, and ponds, as well as vegetated wetlands adjacent to water bodies. Most areas where water flows or gathers (even intermittently) would be considered navigable waters of the U.S. for the purpose of this section. Any project that involves construction in or adjacent to waters of the U.S. can Potentially impact the quality or function of the waters. Water quality can be impacted by physical disturbance and by the discharge of sediment, construction debris, pollutants, or other materials such as oil or other vehicle fluids. The functions of navigable waters and wetlands can be impacted by activities such as the disposal of soil and construction materials; excavation; the placement of structures such as culverts, storm drain outfalls, bridges, and buildings; and modifying the amount or quality of water flow to the existing bodies of waters due to adjacent landscape modifications. In general, FEMA is concerned with any construction activities within 200 feet of waters of the U.S., and requests additional documentation in Section D of the Environmental /Historic Preservation Questions for those projects.

If your project is in or near navigable waters of the U.S., you have probably collected information about this resource already in Section C of the Environmental /Historic Preservation Questions. If not, be sure to read Section C, and provide the information requested on that page.

Referencing a United States Geological Survey (USGS) topographic map [example map ] is an easy way to check for nearby waters of the U.S. Be sure to use a 1:24,000 scale topographic map; any scale greater than this may not show all water body features. Water bodies are represented on USGS topographic maps in blue (on maps showing water body types). One way to find out if there are wetlands nearby is to reference the wetland maps on the National Wetlands Inventory website. Care should be taken when referencing these maps; not all wetlands are included on the maps they maintain.

The most reliable way to determine if there are wetlands or navigable waters of the U.S. in your project area is to contact the United States Army Corps of Engineers (USACE) [// ] , an appropriate state regulatory agency such as the department of environmental protection, or a local agency such as a stormwater management district.

In your communication with the USACE or other agency, you should:

  • Indicate you are applying for federal aid, and you are requesting information about the presence of jurisdictional waters or wetlands in your project area
  • Include the name of the nearest city and the names of the county and state where the project will occur
  • Include a description of the proposed project
  • Include a 1:24,000 USGS topographic map marked with the project location

If you have determined that there are waters of the U.S. in your project area, the next step is to determine the potential impact to the body of water. The USACE (or the US Fish and Wildlife Service (USFWS) from your work in Section C) may indicate a potential to impact a water of the US in the agency’s response to your request for information. You can also determine potential impacts by carefully reviewing your project scope of work. If your project indicates that it involves work in the water, excavation of material from the water or placement of material in the water, then you should answer “yes” to Section D, Question 1 of the Pre-Disaster Mitigation (PDM) Environmental and Historic Preservation Questions.

Projects that typically result in a “Yes” answer to Section D, Question 1 include:

  • Culvert replacement or realignment
  • Drainage improvements, to include straightening, widening and deepening on channels, ditches, or other water bodies
  • Construction of retention or detention ponds,
  • Work on bridges
  • Stream bank stabilization
  • Any construction within 200 feet of a waterway that could contribute to erosion or sedimentation.

Waters of the U.S. and Wetlands

There are a range of laws and executive orders that are designed to protect the nation’s water resources. Over a century ago, the Rivers and Harbors Act was enacted to address the need to maintain the navigability of the nation’s waterways. Under the Act, regulations and procedures were implemented to control proposed development on or around navigable channels. More recently, the Federal Water Pollution Control Act, later to be called the Clear Water Act, tackled issues associated with cleaning up and maintaining the water quality of the nation’s waters by setting up a permit system under the direction of the US Army Corps of Engineers (USACE). Any entity, Federal or non- Federal, who is developing in or around “waters of the US” (which includes wetlands), is required to contact the USACE about the need for a permit. If a permit is required, it must be obtained and the permit conditions complied with.

In addition to the Clean Water Act and the Rivers and Harbors Act, many states have permitting requirements associated with work in wetlands or streams, along stream banks, or in floodplains. You should check with your state and local authorities regarding these requirements before undertaking any work in these areas.

In addition to the laws enacted by the Congress there are executive orders (EO) issued by the President that relate to actions and funding undertaken by the administrative branch of the Federal government. In particular, EO 11990, Protection of Wetlands, requires that all Federal agencies consider alternatives for proposed actions or funding of actions that would be in or otherwise adversely affect the natural or beneficial functions of wetlands. Where reasonable alternatives are not available, then minimization of impacts must be considered.

The questions and guidance in this section are designed to provide information useful in determining if your proposed project is likely to trigger any of these laws or executive orders and if so, steps and costs that might be involved in reducing the potential impacts.

D: Waters of the U.S. and Wetlands (PDF 118KB, TXT 17KB)

D-1 - Determining if your project will affect "waters of the U.S."
D-2 - Agency Coordination, Permitting, and Evaluation of Alternatives
D-3 - How to Address Adverse Effects
D-4 - How to Provide Relevant and Helpful Support Documentation


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