Wetland mitigation monitoring

When mitigation is required to compensate for unavoidable impacts to wetlands and other aquatic resources, a monitoring plan should be included in the mitigation plan. The goals, objectives, and performance standards for a mitigation project are the basis for the monitoring plan. It is the measure against which compliance and success are determined. The duration, frequency, and methods of monitoring depend on a project's goals, objectives, and performance standards.

In general, monitoring is required for 10 years. The monitoring period may be extended if performance standards are not being met.

Monitoring helps ensure that a mitigation project achieves its stated purpose and complies with permit obligations. It also provides critical information about whether a site needs maintenance or whether the applicant needs to take corrective actions.

Washington state requirements


In Washington, the U.S. Army Corps of Engineer's (Corps) Seattle District refers to Regulatory Guidance Letter (RGL) 08-03 for guidance on minimum monitoring requirements for mitigation projects, including the required minimum content for monitoring reports. The Corps requires submission of monitoring reports to assess the development and condition of wetland mitigation projects. The content and level of detail depends on the scale, scope, and type of mitigation.

RGL 08-03 specifies that the monitoring report narrative should be concise and generally less than 10 pages. This length requirement helps to ensure that only pertinent information is submitted. This helps expedite agencies' review and determination of whether the mitigation project is in compliance.

For specific projects, the Corps' Seattle District determines how frequently monitoring reports are submitted, the monitoring period length, and report content. Permit conditions will support the specified monitoring requirement and include deadlines for monitoring report submittal. The Corps will also accept monitoring reports that follow our guidelines, provided permittees also include panoramic photographs of the mitigation site with the monitoring report.


RGL 08-03 is consistent with Washington's interagency wetland mitigation guidance. In most cases, monitoring reports are required as a condition of our certification or order.

Monitoring report contents

For specific projects, we typically list the required monitoring information in an attachment to the certification or order. For orders that do not have this attachment, refer to RGL 08-03.

Submittal requirements

The relevant conditions listed in our order will help you determine the specific submittal requirements for your project. For more recent projects, the condition will say something such as: “The applicant shall submit to Ecology one hard and one electronic copy of monitoring reports documenting mitigation site conditions for years 1, 2, 3, 5, 7, and 10.”

We need at least one paper copy of each monitoring report; however, the agencies also encourage reports to be submitted electronically. This allows for easy distribution to the appropriate agency staff and will limit the number of paper copies needed. There should be an address listed in our order for whom to submit monitoring reports to (this is usually the Federal Permit Manager in the region where the order was issued). The electronic copy can be sent via email if it is 30 MB or less. If it is larger than 30 MB, you can send a copy on a CD.

Failure to submit completed monitoring reports in a timely manner could result in an extension of the monitoring period or additional mitigation requirements.