Lions Open Space Bank Restoration and Stabilization

Lions Open Space Reconstructed Riverbank During Spring Runoff

Pre-Project Erosion Damage

Bank Erosion

Bank Reconstruction of North Riverbank

Reconstructed Riverbank During Spring Runoff

Project Summary

Lions Open Space northwest of Fort Collins is a day-use area offering picnicking, fishing, hiking and biking.  It is also home to the westernmost portion of the Poudre River Trail. In September 2013 the Poudre River in this area experienced flooding at an approximately 50-year level which caused considerable damage to recently installed bank protection measures. Early spring of 2014 brought heavy snows to the Poudre River headwaters resulting in snowmelt runoff on the Poudre River that remained at or near bankfull through Lions Open Space for nearly three weeks. Damage to the east channel bank was extensive with the loss of nearly all the protection measures. The damage included lateral bank retreat of up to almost 30 feet, causing concern for existing park infrastructure, the Poudre Trail, and the safety of park patrons and trail users. Anderson Consulting Engineers performed hydraulic analysis of the river and developed new designs for restoration and stabilization of the 500-foot reach along the eastern bank of the river through Lions Open Space.


  • Client/Owner: Larimer County Natural Resources Department
  • Project Location: Larimer County, Colorado
  • Approximate Project Cost: $455,000
  • Project Completion Date: September 2019
  • Project Components:
    • Hydraulic analysis of the Poudre River adjacent to Lions Open Space

    • Final designs for restoration and stabilization of a 500-foot reach along the east bank of the Poudre River
    • Rock vanes used to create varied flow areas along the reconstructed toe
    • Erosion countermeasure design using rock riprap and a boulder toe
    • Realignment and reconstruction of the Poudre River Trail within the 100-year floodplain

    • Revegetation of the entire project area
    • Conducted yearly stream restoration monitoring of the project area for a 3 year period 
    • Monitoring program followed the guidelines of the Colorado Water Conservation Board’s (CWCBs) 2010 Measurable Results Program intended to evaluate the performance of stream restoration projects
    • Evaluation of changes to channel planform, the channel thalweg profile, profiles along the left and right toes and tops of bank, and channel cross sections
    • Monitoring program demonstrated that the project performed as intended, with some natural adjustments occurring within the river channel, but the channel bank restoration/stabilization measures providing the necessary protection.
    • Permitted through Larimer County by demonstrating no-rise under a Floodplain Development Permit

    • LOMR was completed and approved by FEMA in October 2019, LOMR became effective in February 2020

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