The Louisville District website ( is moving to the Great Lakes and Ohio River Division website ( This website is scheduled to be decommissioned on July 15, 2024. Please update all saved links to

Wetland Information & Resources

The U.S. Army Corps of Engineers (Corps) and the U.S. Environmental Protection Agency define wetlands as follows:

Those 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.

In general, wetlands are areas with wetland vegetation (cattails, rushes, sedges, willows, etc.) where the soil is saturated or flooded during a significant portion of the year during most years. Wetlands include swamps, marshes, bogs, and similar areas. Wetlands such as swamps and marshes are often obvious, but some wetlands are not easily recognized, often because they are dry during part of the year or "they just don't look very wet" from the roadside. The information presented below is intended to enable you to determine whether you might have a wetland.

Be aware that wetlands merit special consideration in the Section 404 Regulatory Program regulations. Wetlands are recognized as a productive and valuable resource, the destruction of which is discouraged as contrary to the public interest. In developing plans for a construction site, ample consideration must be given to alternatives, which avoid or minimize impacts to wetlands where practicable. The Corps is restricted from authorizing activities in wetlands where there is a practicable alternative with less adverse impact on the aquatic environment. Once the presumption of the availability of a less environmentally damaging practicable alternative is refuted, remaining wetland impacts, which cannot be avoided or minimized, will require compensatory wetland mitigation. Compensatory wetland mitigation may take the form of wetland restoration, enhancement, construction, or preservation. If you intend to place dredged or fill material in a wetland or in an area that might be a wetland, contact a Louisville District Office for assistance in determining if a permit is required.

The use of the 1987 Corps of Engineers Wetland Delineation Manual and the applicable Regional Supplement is required when any wetland delineation is performed and submitted to the Louisville District. The submitted wetland delineation should be accompanied by appropriate documentation and will be subject to review and validation by this office. Please see the “Wetland Delineation Regional Supplements” subpage of this website in the menu to the right for additional information. Below is an annotated version of the Corps official 1987 Wetland Delineation Manual (Technical Report Y-87-1). This on-line version provides updated interpretations and changes. It also contains important links to other related information (hydric soils data, wetland plants, etc.).

1987 Corps Wetland Delineation Manual (Technical Report Y-87-1)

Agency Programs and Centers

General Information

Hydrology Information

Mapping Tools

Monitoring & Assessments 

National Wetland Plant List

Publications, Handbooks and Manuals

Soil Information

State Information