Contact us


Regulatory image of wetlandsMitigation is an important part of the U.S. Army Corps of Engineers’ (Corps) permitting process. It includes avoiding, minimizing and compensating for impacts to aquatic resources.

If your project cannot avoid or sufficiently minimize affects to wetlands or other waters of the United States, you must compensate for the impacts. Compensatory mitigation provides methods to offset these unavoidable losses due to project impacts. These methods include the restoration, establishment, enhancement and/or preservation of aquatic resources.

Federal Mitigation Rule

Mitigation requirements are outlined in Compensatory Mitigation for Losses of Aquatic Resources Final Rule (33 CFR Part 332), commonly referred to as the “Federal mitigation rule.” The mitigation rule promotes consistency and predictability and improves ecological success of mitigation efforts through better site selection, use of a watershed approach for planning and project design, and use of ecological success criteria to evaluate and measure performance of mitigation projects.

Compensatory Mitigation for Losses of Aquatic Resources, Final Rule (Federal Register, 04/10/08
Corps Headquarters Final Compensatory Mitigation Rule information
Watershed Approach
Watch an introductory video on Mitigation

Providing compensatory mitigation

There are three ways to provide compensatory mitigation:
Mitigation Banks, In-Lieu Fee Programs and Permittee-Responsible Mitigation. Mitigation banks and in-lieu fee programs are generally the preferred options for mitigation because they consolidate resources and involve more financial planning and scientific expertise. These factors help reduce the risk of failure of mitigation projects. The following are acceptable mitigation options;

Collapse All Expand All
 Mitigation bank. Click for more.

A mitigation bank is one or more sites where aquatic resources such as wetlands or streams are restored, established, enhanced and/or preserved for the purpose of providing compensatory mitigation in advance of authorized impacts to similar resources. A bank sells mitigation “credits” to permittees. The obligation to provide mitigation is then transferred to the bank sponsor. The bank sponsor is then responsible for implementing the mitigation, monitoring its performance and long-term site management.

 In-lieu fee program. Click for more

An in-lieu fee (ILF) program involves the restoration, establishment, enhancement and/or preservation of aquatic resources through funds typically paid to state governments, local governments, or non-profit natural resources management organizations. As with banks, credits are sold to permittees by the ILF program sponsor. The in-lieu fee sponsor is then responsible for implementing the mitigation, monitoring its performance and managing the site long-term.

 How to find if credits are available for your proposed project. Click for more
  • The Regulatory In-lieu Fee and Bank Information Tracking System (RIBITS) can be found at This publicly available website can be used to determine if your project location is in the service area of a mitigation bank or ILF site and whether or not there are credits available.

    Once in RIBITS, use the following steps to determine if credits are available for your proposed project:
  1. Under MENU, Tools, select Find Credits
  2. Enter the project latitude and longitude in decimal degrees (4X.XXXXXX, -12X.XXXXXX)
  3. Click on Search

If your proposed project is within a mitigation bank or ILF site with available credits it will populate a list.  You will be able to see how many credits are currently available and the contact information of the sponsor.  You may also click on the bank or ILF site name for more information.

 Full list of NWP mitigation banks and ILF sites. Click for more

To view the full list of mitigation banks and ILF sites within the Portland District area of responsibility, you can use the Regulatory In-lieu Fee and Bank Information Tracking System (RIBITS), found here.  Once in RIBITS, use the following steps to view banks and ILF sites:

  1. Under FILTER, select USACE District
  2. From the drop down select Portland
  3. Under MENU, Mitigation, select Banks & Sites

What to include in mitigation plan:
If you’re using a bank or ILF program, you must submit a mitigation plan. This mitigation plan should include a description of the baseline conditions at the impact site, the number and type of resource credits to be secured and how these were determined. You must also provide the name of the specific mitigation bank or ILF program site proposed to be used.

 Permittee-responsible mitigation. Click for more.

Individual mitigation projects constructed by permittees can also compensate for environmental impacts authorized by the Corps. This option makes the permittee responsible for implementing the mitigation, monitoring its performance and long-term site management. Mitigation projects may occur on the same site as the permitted project or at an offsite location usually within the same watershed. In some cases, permittee-responsible mitigation (PRM) is the only option. This is typical when proposed impacts are not located within the service area of an approved mitigation bank or ILF program, or if these mitigation options would not provide appropriate mitigation for the proposed impacts.

What to include in a mitigation plan

If PRM compensatory mitigation is required, you must submit a mitigation plan. There are 13 required components in every mitigation plan.

The mitigation rule (33 CFR 332.4(c)) describes these 13 components in detail:
1) Preparation and approval (This component is guidance specific and is not included as an actual component of a compensatory wetland mitigation plan.)
2) Objectives
3) Site selection
4) Site protection instrument
5) Baseline information
6) Determination of credits
7) Mitigation work plan
8) Maintenance plan
9) Performance standards
10) Monitoring requirements
11) Long-term management plan
12) Adaptive management plan
13) Financial assurances
14) Other relevant information

Although not required, assistance from a qualified environmental consultant may be beneficial in developing a comprehensive and acceptable mitigation plan. All mitigation plans require Corps approval.

Additional mitigation information and tools

NWP Compensatory Mitigation Special Public Notices

Notice of Release of the Oregon Rapid Wetland Assessment Protocol (ORWAP) Version 3.1

Portland District
Published Dec. 6, 2016

Notice of Release of the Oregon Rapid Wetland Assessment Protocol (ORWAP) Version 3.1 
For the State of Oregon
Issue Date: December 6, 2016

Download a printer-friendly pdf of this notice

The Oregon Department of State Lands (Department) and the U.S. Army Corps of Engineers, Portland District (Corps of Engineers), jointly announce the publication and release of the revised Oregon Rapid Wetland Assessment Protocol (ORWAP) Version 3.1. ORWAP is a tool for rapidly assessing wetland functions and values (as well as other attributes) in all wetland types throughout Oregon. In a regulatory context, ORWAP also can be used to inform alternatives analysis and the selection, design, and monitoring of compensatory wetland mitigation sites. ORWAP, unlike some other methods, is particularly useful because it allows comparisons between different types of wetlands.

ORWAP and its applications were refined by the Department with funding assistance from the U.S. Environmental Protection Agency, Region 10 (EPA). ORWAP indicators and models were modified to reflect new information on wetland functions and values, and to improve its’ usability. ORWAP was applied to a new statistically valid sample of 200 wetlands across Oregon, which allowed ORWAP outputs to be calibrated and relative ratings to be developed. 

ORWAP consists of several different components: a Users Manual; two Excel spreadsheets (ORWAP Calculator and ORWAP Supplemental Information); and a Technical Supplement. The Department, the Corps of Engineers and EPA also cooperatively have developed a guide for using ORWAP for State and federal permit applications.

You may download all of the ORWAP components and the guidance for using ORWAP for permit applications from the Department’s Web site at:

Agency Requirements Regarding ORWAP

ORWAP may be used immediately for both State and federal permit purposes. ORWAP assessments conducted after February 1, 2017 for permit purposes must use version 3.1. Before using ORWAP v3.1 for the first time to assess a wetland for a permit application, read the revised Guidance for Using the Oregon Rapid Wetland Assessment Protocol (ORWAP) in the State and Federal Permit Programs (November 2016 ). This document provides instructions on how to select the assessment area, what to submit to the agencies along with the final scores, how to format the output in a permit application and other important information. The document is available at:

State Removal-Fill Permits—ORWAP is an approved method for assessing wetlands for purposes of the State Removal-Fill Law. Administrative rules governing wetland functions and values assessment may be found in OAR 141-085-0685. These rules explain what type of wetland assessment method is required or allowed for different types of wetlands and impact levels. 

Federal Clean Water Act (Section 404) Permits—Use of ORWAP is recommended, but not required, by the Portland District Corps of Engineers. 

For additional guidance on using ORWAP for state and federal permits, contact:
Dan Hicks, Department of State Lands, 503-986-5320,
Andrea Wagner, Corps of Engineers, (541) 465-6882,
Tracie Nadeau, EPA Region 10, 503-326-3685,

Interested in starting your own mitigation bank or ILF program?

If you are interested in developing a mitigation bank or ILF program in Oregon, contact the Corps, Portland District Mitigation Bank General Inbox; click here