Cameron Peak Fire In-Stream Mitigation

Project Description

In-stream point mitigation projects utilize low-tech wood and rock structures within gullies, rills, and tributary streams to reduce the impacts of post-fire flooding. In the years following a severe wildfire, flooding can occur, especially in smaller tributaries, as excess water runs off hillslopes due to hydrophobic (water repellent) soils and a lack of vegetation. In unburned areas, vegetation and hydrophilic (water absorbing) soils absorb large quantities of water during rain events, reducing the amount of water that runs downhill and into waterways. When the vegetation and topsoil are burned away, rain flows downhill carrying sediment, ash, and debris with it. This leads to the incision of gullies and rills which can funnel water and debris into waterways that often do not have the capacity to handle large flows of water, resulting in flash flood events.

To help reduce the impacts of post-fire flooding, we will install various low-tech wood and rock structures in priority gullies, rills, and streams within the Cameron Peak Fire footprint. These structures help to slow the flow of water while catching sediment and debris. When sediment and debris are retained behind these structures it can raise the streambed helping to reconnect the stream to its surrounding floodplain. This allows for water to spread across the landscape rather than being channeled downstream through narrow waterways which can impact communities, roadways, and water quality. Further, by using native wood and rock on site, these structures become a part of the landscape over time reducing the need for structure removal and maintenance.

Fun Fact

It doesn’t take much rain to cause flooding impacts in a burned area – if 1 inch of rain falls across 10 acres of burned area with hydrophobic soils, over 270,000 gallons of water can flow downhill into waterways. That’s enough water to fill 14 average sized in-ground pools.

Project Photos

Cameron Peak Fire

Post-fire flooding in the Big Thompson has heavily impacted a number of mountain communities washing away roadways, clogging culverts, and damaging houses.

Post-Fire Flooding

Post-fire flooding brings more than water with it. Sediment, ash, and debris are all washed downstream where it can settle in ponds and reservoirs impacting water quality and aquatic life.

Willow Wattle

This “willow wattle” is one of the low-tech woody structures that will be installed in priority waterways to slow flow and catch sediment and debris.

Sediment

In severely incised gullies a mix of wood and rock is used to help backfill the gully by catching sediment behind the rock and wood structure.

Cameron Peak In-Stream Mitigation

Project Accomplishments

We’ll be working on this project throughout 2023, check back at the end of the year to see our project accomplishments!
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