STOP #2
Hahamongna Watershed/Devil’s Gate Dam
Built in 1920, Devil’s Gate Dam was the first dam built by the Los Angeles County Flood Control District. Dams were built in the foothills of the San Gabriels to both control water coming off the steep mountains to prevent flooding downstream and to capture rainwater to replenish groundwater reserves. In 2009 the Station Fire stripped the hillsides of vegetation, which helps hold sediment and rock in place, sending a cascade of debris and sediment down the mountains in 2010’s El Nino rains. The debris buildup behind the dam hit a critical point and spurred the now very controversial sediment removal project.
Dams and catchment basins protect communities below from flooding and help replenish our groundwater, but also disrupt the natural flow of sediment downstream, disrupting the natural ecology of rivers and creeks. How might the area be different without the dams and catchment basins? What plants and animals might return if the water was allowed to flow naturally?
Hahamongna Watershed/Devil’s Gate Dam
Built in 1920, Devil’s Gate Dam was the first dam built by the Los Angeles County Flood Control District. Dams were built in the foothills of the San Gabriels to both control water coming off the steep mountains to prevent flooding downstream and to capture rainwater to replenish groundwater reserves. In 2009 the Station Fire stripped the hillsides of vegetation, which helps hold sediment and rock in place, sending a cascade of debris and sediment down the mountains in 2010’s El Nino rains. The debris buildup behind the dam hit a critical point and spurred the now very controversial sediment removal project.
Dams and catchment basins protect communities below from flooding and help replenish our groundwater, but also disrupt the natural flow of sediment downstream, disrupting the natural ecology of rivers and creeks. How might the area be different without the dams and catchment basins? What plants and animals might return if the water was allowed to flow naturally?