Case Study

Post Wildfire Mudflow and Debris Mitigation in Colorado Springs, Colorado

In June 2012, the Waldo Canyon Fire burned more than 18,000 acres in and around Colorado Springs, stripping vegetation from steep foothill terrain and leaving the region vulnerable to severe post wildfire runoff. While the immediate fire threat passed, the long-term hazard of burn scar flooding, mudflows, and debris slides emerged with every subsequent rain event.

Without vegetation to slow or absorb rainfall, stormwater rapidly mobilized ash, soil, rock, and woody debris. These high-energy flows threatened schools, residential neighborhoods, roadways, and critical facilities, including areas associated with the United States Air Force Academy. Emergency mitigation measures were needed to manage repeated runoff events throughout an extended recovery period.

Project Specifications

Product used: TrapBag® erosion and flood control barriers

Installation configurations: Deflection barriers, linear diversion systems, slope check dams

Material: High-strength woven polypropylene geotextile with dual-layer construction

Fill material: Locally sourced sand, gravel, and soil

Reinforcement: Integrated with rock armoring and drainage improvements where needed

Initial Solution

TrapBag® cellular barriers were deployed across multiple sites as part of a coordinated post wildfire mitigation effort, providing adaptable protection where rigid structures were impractical.

Installations included:

  • Deflection barriers to redirect mudflows away from homes, schools, and occupied facilities
  • Linear diversion systems guiding debris into designated channels and collection areas
  • Slope check dams installed along steep grades to slow flow velocity and encourage sediment deposition

Unintended Longevity

Although initially deployed as emergency mitigation, many TrapBag® installations remained in place through multiple seasons. Their durability under repeated debris impacts allowed communities to maintain protection while long-term watershed stabilization and revegetation efforts progressed.

Project Expansions and Reinforcements

As erosion patterns evolved, TrapBag® alignments were adjusted in the field and expanded as needed. In several locations, the systems were paired with rock armoring and drainage improvements to create layered protection capable of managing changing flow paths and sediment loads.

Performance

TrapBag® systems performed consistently during repeated rain events following the wildfire, including high-intensity storms that produced fast-moving, debris-laden flows. The barriers resisted impact from rocks and woody debris, reduced flow velocity, and promoted sediment deposition upslope, limiting downstream damage.

Performance highlights included:

  • Stable barrier performance under repeated debris impacts
  • Effective redirection of mudflows away from critical infrastructure
  • Continued function during multiple runoff seasons following the fire
Mudflow mitigation

Key Outcomes

  • Protected residential neighborhoods, schools, and critical facilities from post wildfire mudflows
  • Redirected debris flows and reduced downstream damage risk
  • Enabled rapid deployment and field adjustments as site conditions changed

Conclusion

The Waldo Canyon Fire highlighted the prolonged risks communities face long after flames are extinguished. In Colorado Springs and surrounding foothill communities, TrapBag® systems provided an effective water barrier that adapted to evolving conditions and delivered dependable performance during a vulnerable recovery period.

By combining rapid installation, field flexibility, and durable construction, TrapBag® cellular barriers demonstrated their value beyond traditional flood applications. Coverage of these deployments can be found here:

Installation Highlights

  • Multi-cell cellular barrier configurations used for deflection, diversion, and slope control
  • Double-layer woven polypropylene geotextile for abrasion and debris impact resistance
  • Filled with locally sourced sand, gravel, and soil using standard construction equipment
  • Installed in adaptable alignments to match changing flow paths and steep terrain conditions