Al Tahoe Erosion Control Project 2, EIP #696

Al Tahoe Erosion Control Project 2, EIP #696

Note: Joint Document, ND/FONSI The Project 2 area is adjacent to Lake Tahoe and is characterized by low slopes, seasonal ponding, compacted earthen eroding shoulders that collect and convey flow, and roadsides draining to yards. The predominantly unpaved shoulders in Project 2 range in width from 1 to 10 feet with sporadic vegetation and pavement coverage. Longitudinal slopes along the streets range from 0.2% to 1.2%. Much of the pavement along the side of the roads has deteriorated due to erosion, parking on the shoulders and snow plow damage. The Regan Beach storm drain extends from Lakeview Avenue to Regan Beach via Nevada and Sacramento Avenues. The storm drain consists of Corrugated Metal Pipe (CMP) ranging in size from 18 to 30 inches. The storm drain system outlets directly to Lake Tahoe within the Regan Beach Park with no pretreatment. The storm drain within the park area is in poor condition and the outlet is completely blocked. The storm drain within Lakeview, Nevada and Sacramento Avenues is moderately corroded. A video inspection of the storm drain system completed in summer 2010 showed some sediment and ponded water within the system. The drop inlets (DIs) that discharge to the storm drain have mostly unclogged grates with pine needles and yard waste collected in the inverts. The inlets do not have sediment collection sumps. Drainage complaints by residents of the area refer to standing water, clogged inlets due to snow, and water drainage into driveways and yards. Action is needed at this time to address issues related to water quality in the AI Tahoe Project 2 area because of its direct discharge to Lake Tahoe. Currently sediment and nutrient laden runoff from the project site flows untreated directly to Lake Tahoe. There is a need to maximize source control through shoulder rehabilitation and provide pretreatment and intensive filtering for storm water discharge to Lake Tahoe. Additional water quality benefit would be gained by replacing portions of the Regan beach storm drain with perforated High Density Polyethylene (HDPE) pipe. The existing outlet to Lake Tahoe will be abandoned and removed from the beach and replaced with an alternate outlet on the west end of the Park which is in line with proposed pretreatment and media filter. The proposed perforated HOPE would resist corrosion and enhance infiltration while providing more effective drainage and storm water treatment for the project area. A portion of the storm drain within Regan Beach Park will be replaced in Al Tahoe Project 2 in order to continue to serve the existing inlets within the park. In the future proposed Park improvement will reconfigure the inlets, and the future park inlets can be connected to the Al Tahoe Project 2 storm drain and pretreatment at the proposed manholes.

South Lake Tahoe

El Dorado