NRCS EXIGENT STREAM BANK STABILIZATION

Engineered and bioengineered bank stabilization in Lyons, Co
A bendway wier re-stabilizing the river and bankside

Lyons, Colorado

S2O Design provided design and construction management services for the emergency watershed protection project in Lyons, Colo. The project was sponsored by the Town of Lyons and funded by the Natural Resources Conservation Service (NRCS), Colorado Department of Emergency Management, and the property owners.

NRCS classified several sites along the St. Vrain River as exigent sites in need of immediate attention to prevent further, future damage to private properties. S2O Design provided designs to protect from flows up to a 25 year return flow for seven properties in Lyons. After the first runoff season, where flows peaked between a five and 10-year return flow, the streambank stabilizations performed as expected. This project was one of the first permanent flood recovery projects to be construction in Lyons.

To accomplish the project objectives, the design aimed to remove large, channel blocking flood debris and stabilizing streambanks with a combination of rock and bioengineering techniques. The rockwork was covered with topsoil and an erosion control blanket. The banks were seeded and trees and willow stakes were placed intermittently throughout the sites. The project includes approximately 450 feet of streambanks on seven private properties.

Project Highlights

  • S2o produced all design drawings and construction documents.
  • Worked with all stakeholders throughout the design and construction process.
  • Streambank stabilization designs protected property from floods up to a 25 year return flow.
  • Designed to provide an economic solution with superior protection.
  • Implemented a combination of hardscape and bioengineering techniques.
  • Placed riprap over the ordinary high water line and then covered it with topsoil and vegetation to mitigate for Preble’s Meadow Jumping Mouse habitat, as well as to produce a more aesthetic streambank.
  • Large woody debris was incorporated to create aquatic habitat.