Wetland Delineation

This is an example of an ortho map from a soil survey. The white lines separate different soil types.

If a wetland exists on property slated for development, the developer will need to mark, or delineate, the boundaries of the wetland. To find out if a wetland has already been surveyed and designated as wetlands, a developer would contact the district office or the U.S. Army Corps of Engineers. If the area is not yet surveyed, the developer must hire wetlands experts ( Society of Wetland Scientists). They might begin by looking at aerial photographs or soil maps of the area (soil surveys available from the US Department of Agriculture). Then they visit the site to evaluate the soils, plants, and hydrology.

The timing of those inspections can be critical. Many evaluators visit wetlands during the summer and fall because that's when wetland plants are most easily identified.

The delineation process should produce:

• Maps showing the size, location, shape and names of features.
• Data sheets listing soil, vegetation, and hydrological indicators.
• Vicinity map that identifies the study area.
• Narrative report describing the above information.

For more info check out the Army Corps of Engineers website on wetlands.

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