Alluvial Fan Stabilization Project (Flood Control District)
The Alluvial Fan Stabilization Project featured the installation of on-forest sediment reduction measures, commonly known as grade control, on the eastern portion of the watershed, which accounts for about 70 percent of the watershed’s overall flows that could yield peak flows up to 100 times higher than pre-fire conditions. Left untreated, these fans would have become impaired and degrade significantly, creating massive head cuts and clogging downstream drainages with sediment. Although no project can completely eliminate sediment, these measures will help to arrest erosion (known as head cutting) and thus the alluvial fan can continue to spread out floodwater, causing some sediment to drop out instead of allowing it to travel downstream and fill up off-forest drainage structures and impact private properties.
This $231,000 project was funded by a $158,000 U.S. Forest Service (USFS) Regional Advisory Committee (RAC) Grant and the Flood Control District.