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 compensatory mitigation (compensation) 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 compensation 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 compensation projects, including the required minimum content for monitoring reports. The Corps requires submission of monitoring reports to assess the development and condition of compensation projects. The content and level of detail depends on the scale, scope, and type of compensation.

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 compensation 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 compensation 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.” 

Also refer to the order for how (paper copy, electronic, or both) and to whom the report should be submitted. There should be an address listed in our order for whom to submit monitoring reports to (this is usually the wetland specialist in the region where the order was issued and the Federal Permit Coordinator).

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