Upper Elkhorn
Project Goals and Objectives
Improve water quality and ecological functioning by providing opportunities for sediment storage, nutrient uptake, and enhanced aquatic and riparian habitats. Improve stream processes in Elkhorn Creek that align with downstream Wild and Scenic recreation, aesthetic, fisheries, and aquatic habitat values in the Cache la Poudre River. Use process-based restoration techniques to meet the project objectives.
Structure Construction Elements
Log Structures – Burnt trees were felled, placed, and interlocked in the channel to increase roughness, reduce flow velocity, and enhance sediment deposition. These features will limit flow velocities and shear stress that result in erosion. Log structures will also return flow to the overbank areas, reducing incision and rehabilitating the floodplain area. On-site burnt material were primarily used. These features were field fit by the design team and placed to encourage sediment deposition. Placement will utilize the relic beaver dams, where feasible, to reintroduce water areas behind the dams and promote riparian vegetation growth. Post Assisted Log Structure (PALS) – On-site woody material of various sizes was pinned together with untreated posts driven into the streambed to initiate and simulate natural wood accumulation. PALS provide opportunities for sediment storage behind the structures while promoting floodplain connectivity, additional wood recruitment, and riparian health. These features were field fit by the design team and placed to encourage sediment deposition. Placement utilized the relic beaver dams, where feasible, to reintroduce water areas behind the dams and promote riparian vegetation growth. Riparian Revegetation - Recovery of riparian ecosystems is vital to improving water quality. Establishing woody riparian vegetation, primarily willows, increases the capacity for sediment storage, nutrient uptake, and habitat complexity in riparian and aquatic ecosystems. These willows are incorporated into the log structures and PALS to provide additional support. Willow Wattle – Willow stakes are harvested off-site and bundled using biodegradable twine. These bundles are then partially buried and staked into areas with regular baseflow where willows would naturally grow. Willow wattles provide water quality improvements through rapidly establishing woody riparian vegetation to increase sediment storage and nutrient uptake.
Project Photos
Cover Photo