What Is Wetland Delineation? 15 Things (2024) You Should Know

What do you think when you hear the word “wetland” or “delineation”?

If you’re like most people, you think of a swamp, marsh, or bog.

However, that’s not always the case.

Contrary to popular belief, wetlands don’t have to be wet all the time.

Some wetlands can be farmed, mowed for hay, maintained as lawns, or used for other purposes.

They provide a wide array of ecological, economical, and sociological benefits.

For this reason, they’re protected by federal, state, and local regulations.

Because wetlands are protected, if you intend to impact a wetland in any way (i.e., build a new road or drain an agricultural field), then you’ll need to do a wetland delineation first.

In this blog, we’ll tell you everything you need to know about what that is.

Let’s get started.

1. What is wetland delineation?

Wetland identification and delineation establishes the existence (location) and physical limits (size) of a wetland for purposes of complying with the Clean Water Act and other federal, state, and local regulations.

It also provides an element of jurisdictional determination whereby it identifies the water bodies within a project’s boundaries that meet the definition of “waters of the United States.”

When defining a wetland, the U.S. Fish and Wildlife Service looks for three attributes:

bulletThe land supports predominantly hydrophytes (a plant that grows only in or on water) at least periodically

bulletAn underlying substance or layer (the substrate) is predominantly undrained hydric soil

bulletThe substrate is non-soil and is saturated with water or covered by shallow water at some time during the growing season of each year

In essence, wetlands are areas of land that are unable to support specific types of vegetation and animal life due to the soil type and presence of water within the soil for an extended period of time.

2. How do I know if I have a wetland on my land?

Any area that is wet for an extended period during the year could be a wetland.

However, wetlands are not always that easy to spot, and thus, they should be surveyed and delineated by a professional utilizing an approved wetland delineation methodology.

3. Why is it beneficial to protect wetlands?

Most people do not realize why wetlands are so beneficial to them.

Here are the top advantages that wetlands provide to us and the environment.

bulletWetlands improve water quality as they act as a natural filter for nutrients and pollutants.

bulletWetlands help control flooding by absorbing and storing access water.

As a result, they may protect nearby communities and/or buildings from being flooded.

bulletWetlands assist in recharging groundwaters through aquifers.

While you may not realize it, you could very well get your drinking water from an aquifer.

bulletWetlands provide beautiful open spaces for reactional activities and wildlife viewing.

bulletWetlands are essential living spaces for many species and also become a food source; in this way, they protect biodiversity.

4. When do I need to do a wetland delineation?

You should do a wetland delineation if you’re planning a development project, building a new road, or having an agricultural field that needs draining where a wetland may be disrupted or impacted.

Wetland delineations tell you exactly where the wetland location falls within your project plan.

To obtain a permit for impacting a wetland, the delineated wetland boundary must be approved by the USACE and (often) other local agencies that have regulatory authority.

5. When is the best time to conduct a wetland delineation?

The best time to conduct a wetland delineation is during the growing season or the time of year when your soil temperature is above biological zero.

6. How is a wetland delineation conducted?

When you conduct a wetland delineation, you’re seeking three findings:

bulletA delineation results map: This map should clearly define the boundaries of each delineated wetland or stream as well as the location of all data points and the area of investigation.

bulletBoundaries: The wetland and tributary boundaries should be clearly marked in the field with wetland flags to aid in agency verification.

bulletReport: The final report should include the following:

    1. Delineation methods
    2. Results
    3. Data forms
    4. Documentation of the findings
    5. Photographs
    6. Climate conditions (both before and at the time of the delineation)
    7. Other relevant figures

To achieve these three goals, the delineator will follow these steps:

bulletStep #1: Review resources

A delineator should prepare by researching the project area.

This involves using mapping products such as aerial photographs and soil maps to identify potential aquatic resources.

Here are some essential resources that the delineator may use:

  1. Aerial photos
  2. National Wetlands Inventory – U.S. Fish and Wildlife Service (USFWS)
  3. Soil survey by Natural Resource Conservation Service (NRCS)
  4. Topography
  5. Relative local or state-level maps that could exist for wetlands (e.g., state departments of natural resources often have localized maps of known wetlands and aquatic resources)

The resources needed will likely depend on the size of the delineation project.

bulletStep #2:  Prepare field gear and review field procedures

The delineator must have all the proper field gear on hand.

Here are some of the must-haves that will allow the delineator to perform their job.

  1. Wetland delineation flags and tape
  2. Hat
  3. Backpack
  4. Bug spray and sunscreen
  5. Munsell soil color chart book
  6. Soil auger
  7. Wetland plant books
  8. Waterproof field notebook
  9. Waterproof field notebook
  10. GPS unit
  11. Boots – muck, hiking, waders
  12. Cell phone
  13. Waterproof field camera
  14. Soil knife
  15. Two-way radios or “spot” phones for working in remote areas
  16. Rain jacket
  17. Food and water for long days

At the field, the delineator will:

  1. Look at the vegetation
  2. Locate the topographic break
  3. Complete a soil sample

bulletStep #3: Draft a report

The content of the wetland delineation report should consist of the following format:

  1. Introduction: Site description and purpose for the delineation
  2. Wetland delineation description and methods (definition, methodology, hydrophytic/wetland vegetation, hydric/wetland soils, wetland hydrology)
  3. Results: Description of the wetland identified and regulatory considerations
  4. Bibliography
  5. Tables, figures, and appendices

Once the report is complete, it can be submitted to the wetland regulatory agency for review.

7. How long is my wetland delineation good for?

After the report is approved, a wetland delineation determination is good for five years.

If your project is planned to begin after that timeframe, then we recommend waiting until closer to the initiation of the project to get your wetland delineation.

8. What happens if a wetland is found?

If a wetland is found during your wetland delineation, then the U.S. Army Corps of Engineers (USACE) will determine whether your wetland area is jurisdictional and in need of protection.

If it’s not jurisdictional, then you’ll be cleared for construction.

9. What is wetland reconnaissance?

Wetland reconnaissance is a general property assessment that determines if critical areas are present on a property.

If none are found, the product is a letter-style report confirming the absence of critical areas that may be used for permitting purposes.

If a wetland is found, the general location and estimated buffer size are described in a report that may assist you in evaluating if the property will meet your needs.

Note that the report cannot be used for permitting when wetlands are present.

You’ll need to get a wetland delineation to determine impacts.

10. What is the difference between wetland delineation and wetland reconnaissance?

Are you wondering what the core differences are between wetland delineation and wetland reconnaissance?

To help, we’ve provided the main points that you’ll need to know about each.

bulletWetland delineation

  1. Required by local jurisdictions when critical areas are present.
  2. Usually required if prior delineation study is 5+ years old.
  3. Detailed analysis of critical area types, boundaries, and buffer widths present on-site.
  4. Wetlands or stream boundaries are flagged for surveys.
  5. The client will receive:
    • A report that may be used for permitting.
    • Wetland determination and rating forms.
    • A sketch or GPS map with flagged locations of wetland boundaries.

bulletWetland reconnaissance

  1. Useful for those considering a property purchase.
  2. Quick determination verifying whether critical areas are present (no flags hung).
  3. The client will receive:
    • A report describing the presence or absence of wetlands.
      • If wetlands are present, the report may not be used for permitting.
      • If wetlands are absent, the report may be used for permitting.
    • Sketch of estimated wetland and stream boundaries (if present).

11. How much does wetland delineation cost?

It’s estimated that wetland delineation on a lot under 5 acres costs somewhere between $700 and $850.

The amount of wetland on site and the travel distance are the primary variables in this cost.

12. What is wetland mitigation?

Wetland mitigation was first introduced in the 1975 Farm Bill.

It discouraged the conversion of wetlands for the production of agricultural commodities by making those who converted land ineligible for certain USDA benefits until the functions of the converted wetlands were mitigated or restored.

Converted wetlands (CW) are those that have been drained, dredged, filled, or leveled.

Mitigation” itself is the replacement of the lost function, values, and acres.

Functions and values are replaced through restoration or enhancement of manipulated wetlands; enhancement of degraded wetlands; or creation of new wetlands.

Mitigation sites may be created, restored, or maintained on your land, another person’s land, or land held by a mitigation bank.

The owner of the land where mitigation will take place is responsible for the planning, restoration, and filing of easement documents.

The NRCS (Natural Resources Conservation Service) must approve the mitigation plans.

13. When is wetland mitigation required?

Wetland mitigation is required when a landowner wants to conduct activities that alter wetlands.

Conversion activities include filling, draining, land leveling, clearing woody vegetation when stumps are removed, and diverting run-off water from a wetland.

14. What do you need to do to mitigate?

Wetland mitigation requires the replacement of all lost functions, values, and acres.

With differing functions, the most effective method is replacing wetland type for type.

For example, pothole for pothole or riverine for riverine.

Landowners must develop a mitigation plan that is approved by the NRCS.

Plans may be developed by NRCS as well as qualified consultants.

Be sure to research qualified wetland contractors that you may use for wetland restoration and wetland mitigation planning.

15. Why does wetland mitigation benefit you?

Mitigating your wetlands allows you to maintain your USDA eligibility or potentially apply for USACE permit to develop or alter your property.

It also allows you to “move” wetlands to areas of your land that are more convenient for your operation.

Final Thoughts

If you have or plan to purchase land with wetlands, make sure you’re aware of the regulations surrounding them!

Sometimes people plan to develop their land without a second thought about the protections that exist.

Wetlands are vitally important to our environment, and thus, you can’t just develop them without some serious planning.

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Erika Gokce Capital

Disclaimer: we are not lawyers, accountants or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.


6 thoughts on “What Is Wetland Delineation? 15 Things (2024) You Should Know”

  1. Can We build a tree house on Wetlands in Cowlitz County Washington???

    • Hello Joseph, a tree house would still likely require a permit, but I would recommend speaking with the relevant county office and the local army corps of engineers.

  2. Hi, thanks for the great article. Is there a course or some way I can learn how to do wetland delineation? I’m an environmental scientist, but I was not taught how to do this.

    • Hello Sean,

      That’s a good question. I did a quick google search and found this course: https://cpe.rutgers.edu/wetlands

      It’s also possible your local university has one. I hope this helps!

  3. I have a lot of property which was used in the past for carrots, grazing and had a one house schoolhouse on it up till 1950’s. I’m trying to put in a small plot of blueberrys and some bees, and have has a 12×24 shed on skids on the property for 3 years. Humbolt county is saying I need a biological, , botanical, wetland delineation report? There is a long standing lot line dispute with this property and my neighbor made a false complaint that someone was living on the property. Any suggestions. I’m just want peace. Have paid county 6000. For a permit to keep the structure and 2000 for a flood level certificate from an engineer.

    • Hello Angie, unfortunately, I believe you need to comply with whatever the town asks you to do. Are they asking for more than the permit you already received? You may also want to speak with a real estate attorney about your dispute with your neighbor.


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