Due to wildfires and heavy precipitation events, a large volume of sediment has
migrated into the Dam 5 impoundment. SCE is concerned that continuing accumulation of sediment could cause a collapse of the dams’ intake gates. To avoid
this collapse, SCE proposes mechanical removal of the sediment. To access the Dam 5 impoundment, SCE will draw down the Dam 5 reservoir using thelow-level outlets. Additionally, SCE will expand the existing access road ramp by
approximately 20 feet. The expanded access road will be constructed using up to
200 cubic yards of crushed rock to create a drivable surface. The expanded access
road will be left in place after Project completion. A temporary bypass channel will be
constructed out of two side-by-side 48-inch-diameter culverts to allow flows to bypass
the construction area. SCE will remove approximately 2,000 cubic yards of sediment located adjacent to the Dam 5 intake structure and directly upstream of the Big Creek Powerhouse No.2. The Project will result in no more than 3.24 acres of temporary impacts to the Dam 5 reservoir. Once sediment removal is complete, the ramp and culverts and all imported earthen support materials will be removed. Only the permanent rock fill for the base of the extended access road will remain in place.