Bass Lake Offsite Drainage Project

Bass Lake Offsite Drainage Project

The project is a request for a Grading Permit that will allow grading, excavation, and trenching for the installation of underground storm drains and pipelines; the construction of a concrete lined V-ditch, drainage improvements to the access road and a new 6 acre foot stormwater settling basin. The project includes the following: (1) trench approx. 2,400 linear feet for the installation of diversion pipelines. Pipelines will be constructed of high density polyethylene (HDPE) and will range in size from 12 to 42 inches in diameter. Trenches will be approx. 3 to 18 feet deep with widths to match the diameter of the pipeline. Trenches will be backfilled and compacted after the pipelines are in place. (2) Construct a concrete lined 800 foot V-ditch that will connect the pipelines to the settling basin. Two riprap lined dissipation structures will be located at the connection of the pipelines to receive the stormwater. Additional dissipation structures will be located at the bottom of the V-ditch to regulate flow into the settling basin. (3) Construct a new settling basin with sediment traps to treat the stormwater prior to its exit to the Cosumnes River watershed. The settling basin will be relocated from its existing location (west of Bass Lake) to a previously disturbed area approx. 800 feet southeast of the diversion pipeline terminus. The basin will be located approx. 5 feet below the discharge point from the V-ditch. The basin will have slopes along the embankment that will be 3:1. The discharge point will be located either on the northeast or the southeast corner of the basin. The discharge area will have a gate structure with a concrete head wall and be comprised of an 8 inch thick weir wall/gate that includes a slide gate wheel that can be used to regulate flows out of the basin. (4) Improvements to the access road will raise the existing grade so that it will slope away from the Irrigation Reservoir. A 600 foot section of roadway will receive drainage improvements. A shallow earthen V-ditch will be constructed on the upslope side of the access road for stormwater diversion. (5) Operation and maintenance of the proposed project include repairs to the pipeline and V-ditch that could include retrenching and periodic removal of vegetation and sedimentation to maintain sufficient capacity.

Rancho Murieta

Sacramento

California Department of Fish and Wildlife, North Central Region 2 (CDFW), California Department of Parks and Recreation, California Department of Transportation, District 3 (DOT), California Highway Patrol, California Native American Heritage Commission (NAHC), California Regional Water Quality Control Board, Central Valley Sacramento Region 5 (RWQCB), California State Lands Commission (SLC), Caltrans, Division of Aeronautics, Central Valley Flood Protection Board, Department of Toxic Substances Control, Resources Agency, State Water Resources Control Board, Division of Water Rights, Department of Water Resources

Department of Water Resources

Waste Treatment:Other (Irrigation Reservoir)

Grading Permit

Aesthetics, Air Quality, Cultural Resources, Drainage/Absorption, Geology/Soils, Hazards & Hazardous Materials, Land Use/Planning, Noise, Wildlife