As floods and other natural hazards increase in frequency and severity across the United States and other nations worldwide, Natural and Nature-Based Features (NNBFs) are becoming a widespread solution for disaster risk mitigation. The NNBF design provides strengths in dynamic adaptive capacity to extreme events and multi-functional benefits beyond projects’ targeted mitigation goals. However, uncertainties on the performance, behavior, and longevity of NNBFs, and the lack of both regulated protocols and long-term documented outcomes, introduce challenges and considerations beyond those imposed on static gray infrastructure. The permitting step in the NNBF process is often complicated by the additions of uncertainty and risk through variability in ecosystem functions and unreliable predictability in NNBF operational success. Permitting and environmental review processes are also dependent on national, state, and regional contexts, and there are few actionable guidelines to NNBF projects across these sociopolitical and ecological domains. This research aims to address gaps in existing permitting guidelines and practices by providing a federal planning level review to inform and improve NNBF implementation efforts. By coupling interviews with U.S. Army Corps of Engineers project managers, regulators, and planners with review of existing permitting literature, we found examples of successful NNBFs and concluded that cross-agency coordination during conceptualization and design phases is critical for successfully implemented and maintained projects. Through communicating NNBF permitting options, examples, and recommendations based on these perspectives, this effort creates opportunity for more focused guidance on the permitting and environmental review processes and provides a framework for future projects.
