An Assessment of U.S. Stream Mitigation Policy: Necessary Changes to Protect Ecosystem Functions and Services

Abstract:

Compensatory mitigation of impacted streams and wetlands has increased over the past two decades, with the associated mitigation industry spending over $2.9 billion in aquatic restoration annually. Despite these large expenditures, evaluations by the National Research Council (NRC) and U.S. Government Accountability Office (GAO) have provided evidence that compensatory mitigation practices are failing to protect aquatic resource functions, and vague federal policy and inadequate evaluation of compensation projects are to blame. An update to federal guidance on compensatory mitigation was released in 2008: the Compensatory Mitigation for Losses of Aquatic Resources. Additionally, the 2012 Reissuance of Nationwide Permits was recently updated and published. Current policy, as reflected in these documents, still uses vague language to direct compensatory stream mitigation leaving most implementation decisions (e.g., geographic scale of compensation, stream restoration methods) to the local U.S. Army Corps of Engineers (USACE) District. The majority of mitigation federal policy has focused on wetland compensation, paying minimal attention to other aquatic resources (e.g., streams) and mitigation alternatives (e.g., avoidance and minimization). Interest in stream compensatory mitigation is growing. In this presentation, weaknesses of current policy and recommended changes to minimize the loss of stream ecosystem services are presented. Compensatory mitigation policy should contain more detailed criteria, to prevent large implementation variations between USACE Districts, and provide clear guidance for watershed scale compensatory stream mitigation. In addition, stronger and more detailed criteria for avoidance and minimization alternatives should be enacted to reduce the need for compensatory mitigation for difficult to restore aquatic resources.