How Long Is a Wetland Delineation Good For?

Key Takeaways:

  • A wetland delineation is typically valid for 5 years from the date of approval.
  • After 5 years, a new wetland delineation will need to be done before impacting wetlands.
  • Longer validity periods up to 5 years may apply for certain projects.
  • Proper timing helps avoid costs of prematurely re-doing the delineation.
  • Factors like site conditions and regulations determine useful life of delineations.


Wetlands provide a wide array of ecological, economic, and social benefits, such as flood control, water purification, and wildlife habitat. To protect these vital resources, section 404 of the Clean Water Act requires permits before dredging or filling wetlands. An essential first step is completing a wetland delineation to identify the boundaries and extent of wetlands on a property. This comprehensive evaluation and technical report is submitted to the U.S. Army Corps of Engineers for approval.

A key consideration is how long an approved wetland delineation remains valid before requiring an update. Proper timing of the delineation process can avoid unnecessary hassle and added project costs. This article will analyze the typical duration, factors that influence the shelf life, and recommendations for maximizing the utility of a delineation. After reading, you will have a clear understanding of how long you can rely on a wetland delineation before an update is needed.

Wetland delineations require considerable time and expense to complete. By planning the delineation early enough to avoid premature expiration during a project’s timeline, developers can realize significant cost savings by not having to redo the delineation process. However, delaying the delineation risks project delays if the approval expires before construction begins. Understanding duration and timing considerations provides an invaluable roadmap for efficient project planning and execution.

What is the Typical Validity Period of a Wetland Delineation?

The U.S. Army Corps of Engineers, which must approve all jurisdictional wetland delineations, generally considers delineations to be valid for five years from the date of approval, provided site conditions have not changed significantly.

According to a 2014 regulatory guidance letter, the Corps stated that approved jurisdictional determinations, including wetland delineations, “remain valid for a period of five years unless new information warrants revision of the determination before the expiration date.”

Beyond five years, the delineation is considered expired and no longer accepted. A new wetland delineation study would need to be conducted and submitted for approval before any dredge or fill activities could be permitted.

This five year validity mirrors the maximum term of Department of the Army permits issued for projects impacting wetlands. Nationwide permits are issued for five years. Individual permits are typically issued for three years but can be extended to five years.

Therefore, for general planning purposes, an approved wetland delineation can be relied upon for five years. Significant changes at the site may warrant revisions sooner, while certain projects may qualify for longer validity.

Can a Wetland Delineation Remain Valid for Longer Than 5 Years?

While five years is the standard duration, the Corps has discretion to provide a longer validity period in certain circumstances when warranted by the project.

According to Corps guidance, durations longer than five years, but not exceeding five years, may be appropriate for delineations supporting large linear projects or other long-term projects.

For example, large pipelines or highway projects that take many years to construct may need a delineation validity period greater than five years. The Corps will determine validity timeframes based on the anticipated start and completion dates of each phase of such phased projects.

Additionally, if site observations and all scientific data collected during the original delineation remain valid, the Corps may determine that conditions continue to support the original delineation even after five years. However, this depends heavily on site-specific conditions and regulations.

Barring such exceptions, delineations for typical projects can expect approvals lasting up to five years under normal circumstances. Any desired validity longer than this standard duration should be discussed early with the regulating Corps district.

What Factors Determine How Long a Delineation Will Remain Valid?

Several key factors affect the useful life of an approved wetland delineation before an updated study is required:

Site Conditions and Characteristics

The validity period largely depends on whether site conditions remain stable over time. Delineations are based on examining soil, hydrology, and vegetation characteristics. Significant changes to wetland boundaries, vegetation communities, hydrologic flows, or soil profiles could render the delineation obsolete prematurely.

Highly dynamic sites, such as streams and coastlines, are likely to require more frequent delineation updates as the site evolves. Stable wetland types, like forested swamps, may undergo fewer changes over five years.

Development Activities

Construction, land clearing, grading, or hydrologic modifications on or near the site could alter wetland boundaries or characteristics, necessitating an updated delineation.

Natural Events

Major storms, floods, wildfires, or other events may alter site conditions to change the accuracy of the existing delineation.

lapse of Time

Even without major changes at a site, the Corps presumes delineations start becoming outdated after five years due to minor vegetation changes, hydrology fluctuations, and other gradual site alterations.

Regulatory Changes

New or modified regulations, expanded jurisdiction, or improved delineation methods may necessitate revisions to bring existing delineations up to current standards. Periodic federal rule changes affect Corps review criteria over time.

By understanding these potential variables at a site, developers can anticipate when an update is likely to be needed and factor this into project timelines.

How Can You Maximize the Useful Life of a Delineation?

Proper timing is key to avoiding the hassle and costs of premature expiration. Here are some tips for maximizing the working life of your wetland delineation:

  • Plan the delineation early – Allow enough time for the delineation to receive approval well in advance of anticipated permit application and construction start dates. This avoids scrambling for an updated delineation while the project clock is ticking.
  • Discuss longer validity – If the project timeline warrants a validity period exceeding five years, negotiate this extended duration early with the Corps to prevent surprises down the road.
  • Monitor site conditions – Periodically check if changes to hydrology, vegetation, or soils could affect boundaries or jurisdiction before the five years are up. Proactively address potential discrepancies.
  • Consider contingencies – Build contingencies into project schedules in case the delineation does expire before completion or in case revisions are needed.
  • Maintain accurate records – Keep the original delineation report, maps, data sheets, and correspondence handy for easy reference and comparison if an update is ever required.

With proper diligence and planning, a wetland delineation can remain a reliable reference for most projects for five years or longer without having to undergo a costly redo.

Frequently Asked Questions

Does a wetland delineation automatically expire after 5 years?

No, wetland delineations do not have a mandated expiration date in regulations. The Corps generally considers them valid for 5 years, but may allow longer periods on a case-by-case basis depending on site conditions and project duration.

Can you request a specific validity period for a delineation?

Yes, applicants can request a desired validity period based on project-specific needs when submitting the delineation to the Corps for approval. The final duration will be determined by the Corps based on regulatory criteria.

What happens if a delineation expires before your project is done?

If the delineation expires, you will have to stop work and undergo the process of conducting and obtaining approval of an updated wetland delineation before resuming any dredge/fill activities in Corps jurisdiction.

Can minor wetland impacts be authorized without a current delineation?

No, the Corps requires an approved wetland delineation valid through the permitted activity period regardless of impact acreage. Delineations define the authorized boundaries.

How much does a new wetland delineation cost if the old one has expired?

The cost to redo a wetland delineation can range from $5,000 to $15,000 on average, with factors like site acreage affecting the total fees. Proper timing can avoid these unnecessary costs.


Wetland delineations are vital precursors to obtaining Corps permits for projects impacting wetlands. Their usefulness is limited to an approval period dictated by site stability and project duration. Generally valid for five years, longer durations are possible for large linear projects or very stable wetland conditions. Proper timing, monitoring, and contingencies can prevent costly hassles from delineations expiring prematurely. This guide provides a five year rule of thumb and planning strategies to maximize the working life of your wetland delineation.


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