Mitigation Overview

Mitigating the environmental impacts of necessary development actions on the Nation's wetlands and other aquatic resources is a central premise of Federal wetlands program.

Compensatory mitigation is the third step in the sequence of actions that must be followed in the review process, the first being to avoid, then to minimize and finally to mitigate for any unavoidable impacts. The Clean Water Act (CWA) Section 404 permit program relies on the use of compensatory mitigation to offset any unavoidable adverse impacts which remain after all appropriate and practicable avoidance and minimization has been achieved.

The objective of the Clean Water Act (CWA) is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” Toward achievement of this goal, the CWA prohibits the discharge of dredged or fill material into wetlands, streams, and other waters of the United States unless a permit issued by the U.S. Army Corps of Engineers (Corps) or approved State under CWA Section 404 authorizes such a discharge. When there is a proposed discharge, all appropriate and practicable steps must first be taken to avoid and minimize impacts to aquatic resources. For unavoidable impacts, compensatory mitigation is required to replace the loss of wetland, stream, and/or other aquatic resource functions.

Mitigation for the unavoidable adverse impacts to aquatic resources may occur through the following methods restoration, establishment, enhancement and, in certain circumstances, preservation. The preferred hierarchy, as stated in the EPA/ Corps Mitigation Rule, for the forms and location of compensatory mitigation is as follows:

1. mitigation bank credits from an approved mitigation bank,
2. in-lieu fee (ILF) program credits from an approved ILF program,
3. permittee-responsible mitigation under a watershed approach,
4. permittee responsible mitigation through on-site and in-kind mitigation, or,
5. permittee-responsible mitigation through off-site and/or out-of-kind mitigation.

What is compensatory mitigation? 

The fundamental objective of compensatory mitigation is to offset environmental losses resulting from unavoidable impacts to waters of the United States authorized by DA permits and to replace the loss of wetland, stream, and/or other aquatic resource functions. Compensatory mitigation involves the actions taken to offset unavoidable adverse impacts to the aquatic ecosystem after all appropriate and practicable steps have been taken to avoid and then minimize adverse impacts to wetlands, streams, and other aquatic resources authorized by Clean Water Act section 404 permits and other Department of the Army (DA) permits. Compensatory mitigation can be carried out through the restoration of a previously-existing wetland or other aquatic site, the enhancement of an existing aquatic site’s functions, the establishment (i.e., creation) of a new aquatic site, or, in some cases, the preservation of an existing aquatic site.

When is Mitigation Required?

The mitigation sequence established by the Clean Water Act Section 404(b)(1) Guidelines has been retained in the Mitigation Rule. Proposed impacts must first be avoided to the maximum extent practicable. Remaining unavoidable impacts must then be minimized. Finally, unavoidable impacts must be compensated for to the extent appropriate and practicable.

In Maryland, where stream compensatory mitigation is required, the Maryland Stream Mitigation Framework Version 1 Final (MSMF V.1. Final) will be implemented to quantify stream debits for DA permit applications where greater than minimal stream losses occur.  Additionally, it will be used to quantify stream credits awarded for mitigation work to offset unavoidable stream impacts.  MSMF V.1. Final can be found at the bottom of this page.  It includes a user manual, a stream debit and credit calculator workbook (Appendix A1), and several additional attachments which are used to populate the debit/credit calculator workbook (Appendix A1) such as functional and conditional assessments.

EPA/Corps Mitigation Rule

The EPA/ Corps Mitigation Rule establishes the standard to improve the planning, implementation, and management of compensatory mitigation projects by emphasizing a watershed approach in selecting compensatory mitigation project locations, requiring measureable, enforceable ecological performance standards and regular monitoring for all types of compensation, and specifying the components of a complete compensatory mitigation plan, including assurances of long-term protection of compensation sites, financial assurances, and identification of the parties responsible for specific project tasks. This rule also significantly revises the requirements for in-lieu fee programs to address concerns regarding their past performance and equivalency with the standards for mitigation banks and permittee-responsible compensatory mitigation.

The Corps and the Environmental Protection Agency have issued regulations governing compensatory mitigation for activities authorized by permits issued by the Department of the Army. The regulations establish performance standards and criteria for the use of permittee-responsible compensatory mitigation, mitigation banks, and in-lieu programs to improve the quality and success of compensatory mitigation projects for activities authorized by Department of the Army permits.

Mitigation Banking and In-Lieu Fee Programs

RIBITS (Regulatory In-lieu fee and Bank Information Tracking System) is an interactive web-based mitigation and conservation banking and in-lieu fee program tracking system. RIBITS allows the public to find and track the status of USACE approved mitigation banks and in-lieu fee programs nationally and within the Baltimore District. It provides up-to-date information about the availability of compensatory mitigation credits that may be purchased to offset adverse impacts that are authorized by a Department of the Army permit. RIBITS provides federal, state, and local regulations, policies, and guidance governing the mitigation bank and in-lieu fee establishment processes. This system also contains information to guide the prospective sponsor through the bank or in-lieu fee establishment process, including district procedures; site protection instrument templates; performance standards and monitoring protocols; financial assurances, and schedule of credit availability.

Mitigation banks are sites approved by the Corps to sell compensatory mitigation credits for projects resulting in unavoidable impacts to wetlands and waterways. When a Department of the Army permit is issued requiring purchase of credits from an approved mitigation bank, the permit will specify the number and resource type of credits are required to be purchased from an approved mitigation bank. It is the responsibility of the permittee to provide proof of the purchase of these credits prior to initiating any authorized work within wetlands and waterways. Visit RIBITS to determine if your project location is in the service area of an approved mitigation bank or in-lieu fee site and whether there are credits available.

Additional Compensatory Mitigation Information and Tools

U.S. Army Corps of Engineers Headquarters Regulatory Mitigation webpage 

Mitigation Plan Requirements 

RGL 08-03 - Minimum Monitoring Requirements for Compensator Mitigation Projects Involving the Restoration, Establishment, and/or Enhancement of Aquatic Resources

Performance Standards and Monitoring Requirements for Nontidal Wetland Permittee-Responsible Mitigation (PRM) in Maryland

Long Term Management Plan Template-Maryland

Long Term Management Plan Template-Pennsylvania

NAB Mitigation Monitoring Report

Appendix A to Mitigation Monitoring Report Format-Maryland

NAB Advance Permittee-Responsible Mitigation Procedures

NAB Compensatory Mitigation Responsibility Transfer & Sales Notice Template

Permittee-Responsible Mitigation (PRM) Site Protection Instruments

Example Joint Corps-MDE Permittee-Responsible Mitigation Site Declaration of Restrictive Covenant

Maryland Permittee-Responsible Mitigation Conservation Easement Template

PA PRM Conservation Easement

PA PRM Deed Restriction

Financial Assurances

Recommended Bond Surety Companies (renewed yearly in July)

Financial Assurances Regulatory Guidance Letter 05-1

Sample Financial Assurance Cost Estimate Tool

Sample Performance Bond

The Maryland Stream Mitigation Framework Version 1 Final (MSMF V.1. Final)

MSMF V.1 Final Public Notice 09/14/2023

MSMF V.1. Final Manual

Appendix A1_MSMF Version 1 Final Calculator

Appendix A2_MSMF Version 1 Final Calculator

Appendix B_EPA RBP Habitat Forms and Parameters

Appendix C1_Function Based Rapid Stream Assessment with Numeric Scoring 

Appendix C2_FBRSA Rapid-Assessment-Methodology

Appendix C3_Monitoring-Function Based Rapid Stream Assessment

Appendix D1_MSMF Version 1 Stream Buffer Quality Assessment

Appendix D2_Stream Buffer Quality Assessment Instruction

Appendix D3_Monitoring_Stream Buffer Quality Assessment

Appendix E1_Site Evaluation Report for Stream and Wetland Mitigation in NAB_Maryland

Appendix E2_Site Sensitivity Grids for Mitigation in Stream Channels and Stream Buffers