Grading for Single-Family Residence on Slopes Over 10 Percent and Tree Removal Permit, Agreement 2009-0180-R4

Grading for Single-Family Residence on Slopes Over 10 Percent and Tree Removal Permit, Agreement 2009-0180-R4

The proposed Project consists of installing a bottomless concrete box culvert in the unnamed tributary to provide driveway access for a home site. The culvert would measure ~24 ft wide and 21 ft long, with straight wing walls installed and buried in the stream banks to contain fill material. Forms would be constructed and the concrete poured in place. The culvert would accommodate flows from a 100 year storm event. One coast live oak treek, approximately 20 inches diameter, would be removed and replaced at a 10:1 ratio. Approximately 1,400 sf of riparian vegetation would be affected by construction of the culvert. A sediment basin inlet would be constructed next to and immediately upstream from the culvert on the right side (looking downstream) of the stream channel. The basin would include an outlet constructed of rock slope protection near the top of the stream bank to allow water to flow to the creek. At another site, an earthen berm would be constructed in a swale to capture overland flow, retaining water and preventing sediment from entering an unnamed drainage that flows to a pastureland. The berm would be ~20 ft long, 4 ft high, and 8 to 10 ft wide at the base. All disturbed sites would be revegetated and stabilized using generally accepted erosion control practices. All work would be conducted when the sites are dry and devoid of surface flow.

Atascadero

San Luis Obispo