Stillwater engineers and geomorphologists* led the analysis, design, and construction implementation of the innovative design for the River Bluffs project. This project broke new ground in Colorado for functional use of Large Wood (LW) and Small Wood (SW) structures, including placements in the channel, on banks and gravel bars, in overflow channels across the newly reconnected floodplain, and specifically to encourage localized disturbance over time and flood stage, which is critical to sustained ecological diversity and long-term riparian health.
The restoration design process included a comprehensive geomorphic assessment to establish baseline conditions and provide an opportunity to model future conditions to guide habitat design that would be sustainable long-term. Sediment transport modeling was completed to translate invaluable information from an upstream high-functioning reference reach to the design reach, enabling sediment transport continuity across a broad range of flows, from low flow to infrequent higher flood flows.
The vast benefits of large wood in a river system were maximized through extensive installation of wood structures. Rigorous analysis of each individual log was completed to ensure stability. Woody materials were comprehensively restored throughout the site, including placements in the channel, on the banks, on gravel bars, in overflow channels across the newly reconnected floodplain, and via willows and other woody species. Wood features were strategically placed to encourage localized disturbance over time and with different flood stages, which is critical to sustained ecological diversity and health of native riparian species that require bare soil for regeneration.
The River Bluffs project serves as an exciting example of using natural river processes and natural materials to both establish microhabitats for improved biodiversity while accomodoating natural flow regimes for long-term performance and sustainability. This approach increases the resiliency and sustainability for the streams, wetlands, wildlife, and people who use it.
*Stillwater scientists completed portions of this project prior to joining Stillwater Sciences. Stillwater staff are currently conducting construction implementation monitoring to evaluate the performance over time of this innovative approach to restoration.