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The State of Stream Compensatory Mitigation: Science, Policy, and Practice

In 2008, the U.S. Army Corps of Engineers (Corps) and the U.S. Environmental Protection Agency (EPA) released regulations on compensatory mitigation under § 404 of the Clean Water Act. These regulations (“the 2008 Rule”) were intended to improve compensatory mitigation planning, implementation, and management by applying similar standards to all compensation projects and emphasizing a watershed approach to selecting project sites. The Rule also clarified the agencies’ interest in requiring compensation for impacts to streams.

At the same time, stream compensation has been on the rise, as demonstrated by an increase in the percentage of mitigation banks and in-lieu fee programs that provide credits for impacts to streams. The Environmental Law Institute (ELI) reported that in 2005, 12 percent of all approved mitigation banks provided stream credits. By the end of 2014, the Corps reported that 22% percent of all approved mitigation banks provided stream credits. The science of stream restoration is also rapidly evolving, as is the development of state and Corps policies governing stream assessment and compensation requirements. Thirteen states have formalized stream mitigation programs, the majority of which were initiated after the Corps and EPA issued the 2008 Rule, and at least 32 stream mitigation guidance documents and policies have been developed by states and Corps districts across the country. Even so, many decisions are still made on an ad hoc basis, depending on a regulator’s own experience or expertise, and there are few resources available to guide the development of science-based policy on stream assessment and mitigation.

ELI, Stream Mechanics, and The Nature Conservancy have partnered to provide a wide-ranging view of the state of stream compensatory mitigation. The reports examine how stream compensatory mitigation has evolved in policy and practice in the more than seven years since the 2008 Rule, identifying trends as well as areas for improvement and best practices. We also examine how stream restoration science continues to evolve and what progress can still be made. Our goals are to improve understanding about how well stream compensatory mitigation policies are integrating best available science and how well practice aligns with these policies. Ultimately, we hope to inform the development of best practices and comprehensive, science-based stream assessment and mitigation programs.

 

Stream Mitigation: Science, Policy, and Practice

ELI, Stream Mechanics, and The Nature Conservancy (TNC) have partnered to provide a wide-ranging view of the state of stream compensatory mitigation. This report examines how stream compensatory mitigation has evolved in policy and practice and was based on a series of white papers, listed below.

 

Assessing Stream Mitigation Guidelines at the Corps District and State Levels

An assessment of mitigation policies at the Corps district and state levels, including a review of the credit determination methods, performance standards, and other program components currently being applied.

 

Assessing Stream Mitigation Practice

An assessment of stream mitigation practice, including a review of the amounts of stream compensatory mitigation being required and the methods of compensation that are being used to meet permit requirements.

 

A Function-Based Review of Stream Restoration Science

An assessment of stream restoration science, including a literature review and analysis of stream restoration project success rates and restoration approaches.

 

Aligning Stream Mitigation Policy with Science and Practices

An analysis of the stream mitigation best practices and model approaches that can address the challenges to stream restoration success identified in the literature.

 

The documents above were prepared under a Wetland Program Development Grant from the U.S. Environmental Protection Agency.

 

Standard Operating Procedures and Guidance Documents

 Click for a list by state or district.