The Clean Water Act (CWA) is the legislative framework for regulating discharge of pollutants into Waters of the United States (including wetlands). Section 404 of the CWA is considered when assessing impacts to biological resources during the National Environmental Policy Act (NEPA) or the California Environmental Quality Act (CEQA) processes. The US Army Corps of Engineers (the Corps) and the US Environmental Protection Agency (EPA) have enforcement authority for Section 404 of the CWA.

Section 404 of the CWA

Section 404 of the CWA establishes a program to regulate the discharge of dredged and fill material into Waters of the United States, including wetlands.

Activities in Waters of the US or wetlands regulated under this program include fill for development, water resource projects (such as dams and levees), infrastructure development (such as highways and airports) and mining projects. Section 404 requires a permit before dredged or fill material may be discharged into Waters of the US or wetlands, unless the activity is exempt from Section 404 regulation (e.g. certain farming and forestry activities).

The goal of the program is to permit dredged or fill material to be discharged only under one of two scenarios:

  1. No practical alternative exists that is less damaging to aquatic resources, or
  2. The Waters of the US (or wetlands) would not be significantly degraded.

To receive a permit to discharge dredged or fill material into Waters of the US you must prove that you have taken all necessary steps to avoid impacts to aquatic resources, mitigated any remaining potential impacts, and provided compensation for unavoidable impacts.

What are Waters of the US

Waters of the US are under the jurisdiction of the EPA and the Corps, and are subject to Section 404 of the CWA. The definition of waters of the US has recently been re-defined in 2015 by the Clean Water Rule, which helped clarify certain parts of the previous definition that were ambiguous or unclear.

Currently Waters of the US include the following:

  • Traditional Navigable Waters (TNWs) – a body of water is considered a navigable water if it is subject to the ebb and flow of the tide (i.e. has a direct connection to the ocean) or if the body of water is used for interstate or foreign commerce currently, in the past, or could be used for commerce in the future. A water body can be considered a TNW if a federal court has determined that it is “navigable-in-fact under law”.
  • Tributaries of TNWs – to be considered a tributary it must show physical features of flowing water, including a bed, bank, and ordinary high water mark and flow into a TNW (it does not need to flow directly into the TNW, but can be a tributary of a tributary as long as it eventually makes it into a TNW). Headwaters that show these features are also considered tributaries. Under the new rules, this can include waters nearby to lakes and other streams if they share a chemical, hydrological, or other ecological connection besides one that is above ground. The distance for nearby water bodies is assessed on a case-by-case basis. This also includes ditches within tributaries that can meet the definition of a tributary, and are able to carry pollutants downstream to a TNW.
  • Territorial Seas – are defined as “the belt of the seas measured from the line of the ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters, and extending seaward a distance of three miles”

 What are “Wetlands”

Wetlands are also under the jurisdiction of the Corps and the EPA , and are subject to Section 404 of the CWA. The Corps and EPA define wetlands as:

“Wetlands are areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.”

As indicated in the Clean Water Rule, wetlands, lakes, ponds, etc. that are adjacent to “Waters of the U.S.” would be jurisdictional if they can meet the significant nexus test – meaning the adjacent waters must show a significant connection to a Water of the US.

Jurisdictional Delineation

Jurisdictional Delineations are performed on a property in order to identify and delineate which waters are Waters of the U.S. and which are wetlands, and are therefore subject to Section 404 of CWA. The EPA and the Corps use the 1987 Corps of Engineers Wetlands Delineation Manual and Regional Supplements to define wetlands and Waters of the US for the CWA Section 404 permit program. Waters of the US  are defined by the bed, bank, and ordinary high water mark. The 1987 Corps of Engineers Wetlands Delineation Manual and Regional Supplements organizes characteristics of a potential wetlands into three categories:

  • Soils – wetlands have “hydric soils”, which means they are saturated with water and less oxygenated, but also less suitable for plant typical plant growth.
  • Vegetation – wetlands have “hydrophytic vegetation” or plant species that prefer to live in hydric soils where oxygen is low.
  • Hydrology – the presence of standing, pooled, or flowing water is also a good indicator of a wetland, but many wetlands do not have surface water present at some or all parts of the year. A wetland does not need to have surface water present at the time of the delineation to be considered a wetland, but it does need water present at some time during the year.

The manual and supplements contain criteria for each category. With this approach, an area that meets all three criteria is considered a wetland.