New Initiatives Improve Wetland Restoration Outcomes: Engineering with Nature and the Use of Natural and Nature-Based Features

Abstract

For some time, the U.S. Army Corps of Engineers has supported an initiative called Engineering With Nature® (EWN) and the application of Natural and Nature-Based Features (NNBF), both of which promote the incorporation of natural processes and structures into the design and operation of ecological restoration and flood risk reduction projects. Each approach is introduced below, with an emphasis on potential applications in a wetland restoration context. Additionally, examples of recent and ongoing case studies that align with these initiatives are discussed. Historically, practitioners designed wetland restoration projects and assessed their outcomes based upon observations made in unaltered reference areas (Brinson and Reinhardt 1996). However, many restoration projects failed to: follow anticipated trajectories, achieve project milestones, and provide wetland functions at magnitudes observed in unaltered locations (Zedler and Callaway 1999). Differences in landform, hydrology, soils, vegetation community dynamics, and landscape-level ecological processes between restored and reference locations were identified as factors limiting the success of restoration efforts (Zedler 2000). Also, many areas lack appropriate reference areas to determine pre-disturbance conditions which poses a challenge to achieving restoration success (Otte et al. 2021). Recently, researchers and practitioners have increasingly emphasized the integration of natural and nature-based structures and processes into interdisciplinary frameworks to improve restoration project outcomes (Kurth et al. 2020). These concepts build upon previous research recognizing that restoration projects mimicking natural processes and structures provide higher levels of ecological functions than those constructed using traditional techniques (Streever 2000; Foran et al. 2018).