From filtering water and fostering biodiversity to mitigating flooding and sequestering carbon, wetlands are important ecosystems that provide a variety of ecological benefits. 

To ensure that the wetlands are protected, ecologists and conservationists use a process called “wetland delineation” to identify potential wetlands that would be protected under the Clean Water Act. This article will take a look at the process of wetland delineation as well as a few available resources for landowners!

What is Wetland Delineation?

Wetlands delineation is a process used to identify and map the boundaries of wetlands on a property. When performing a wetlands delineation, three main factors are taken into account: soil, vegetation, and hydrology. During an episode of the National Land Podcast, Wade Biltoft and James Mason from Three Oaks Engineering outlined the process of wetlands delineation and how they evaluate these three criteria. Biltoft explained:

“It’s a three-parameter approach. We evaluate the hydrology, is there water present or not? We also look at the vegetation of the area, is the the hydrology giving way to water-loving plants, or is it only plants that are found in dry mountainous habitats occurring here? Then the third is the soils, which kind of ties the other two together. There’s a lot of chemistry involved in how you determine whether the soils meet what would be determined a hydric or a wetland soil.

So wherever all three of those line up, you use your best judgment, hang a flag, and connect the dots around the limit on the property of where these features are.”

Resources for Identifying Wetlands

For landowners looking to learn more about wetland delineation, Mason explained that the Army Corps of Engineers is a good place to start. Mason stated, “Those parameters were outlined based on the 1987 Wetland Delineation Manual that the Army Corps of Engineers published, and that’s a national resource. 

In the past 10 years or so, regional supplements have also been developed that cater to specific regions of the country. So there’s a little more fine-tuning available depending on where you are in the United States in terms of what you’re looking for in those three parameters. There’s some variability, but it all comes back down to the standard three parameters and that basic delineation methodology.”

Biltoft expanded on this point, providing additional resources by stating, “I know a lot of land listings, particularly on National Land, have a wetland layer that can be toggled on and off. What that pulls from is the National Wetlands Inventory. It’s free to the public and it has a mapping tool online that you can Google and access. It’s from the federal government, and it’s basically like a zoomed-out, best guess of where wetlands are likely to be in the United States, based on known soil and floodway data. FEMA also has a lot of publicly accessible floodway data if you’re curious about streams and floodplains on a property as well.” 

Proper wetlands delineation is important for a variety of reasons. Failing to identify a wetland on a prospective development tract could cost a land buyer lots of time and money, and could even get them into trouble with the State or Federal government. Wetlands delineation is also often a prerequisite for obtaining building permits to ensure that landowners and developers are following environmental laws and guidelines. 

If you’d like to learn more about wetland delineation, reach out to Three Oaks Engineering or contact your local Land Professional today!