Assessment of Historic Wetland Compensatory Mitigation Sites in Western Washington State

In this 40-minute national webinar to USEPA Office of Water 404 Mitigation Workgroup, which includes Regions, we will discuss the ROAR Project 2586 "Assessment of Historic Wetland Compensatory Mitigation Sites".

Impact/Purpose

Despite the national “no-net-loss” policy of 1989 that aimed to prevent the loss of wetlands, research has documented that newly constructed (< 10 year old) wetland compensatory mitigation sites (WCMS) constructed through Section 404 permitting do not effectively replace wetlands and their functionality. However, very few studies have assessed wetland mitigation sites that were completed over 20 years ago. This study uses National Wetland Condition Assessment (NWCA) protocols to evaluate sites established through CWA Section 404 permits in the 1980s to address the following questions: (1) Do the historic WCMS still exist? (2) How does site ecological condition compare to the condition of regional natural wetland systems? (3) Is there an ecological return for the permitted wetland loss? Answers to these questions will provide requisite data for staff reviewing CWA Section 404 projects proposing to compensate for wetland impacts with WCMS.  In this presentation, we provide answers to these questions from the 2023 field survey of mitigation wetlands in Washington and findings from final results.

Citation

Nahlik, A., L. Newsom, A. Whitley, M. Kentula, A. Bennett, AND K. Blocksom. Assessment of Historic Wetland Compensatory Mitigation Sites in Western Washington State. EPA 404 Mitigation Workgroup, Corvallis, OR, October 15, 2024.