Capell Storm Damage Project (Project) (Lake or Streambed Alteration Agreement No. 1600-2017-0579-R3)

Capell Storm Damage Project (Project) (Lake or Streambed Alteration Agreement No. 1600-2017-0579-R3)

Caltrans proposes to repair the damaged embankment and improve the drainage systems at two locations. Major items of work include installation of RSP and repair/replacement of existing cross culverts. At location 1 the existing 15-inch corrugated metal pipe (CMP) will be replaced with a 24-inch diameter pipe to better handle storm flows. In the northbound direction the slope will be regarded with an unlined v-ditch. On the Creekside (southbound direction), a drop inlet with manhole will be placed along the edge of the shoulder and the damaged embankment will be repaired with Class I and Class V rock slope protection (RSP) at the new pipe outfall. At location 2 the slope erosion in the southbound direction will be repaired by rebuilding the embankment with soil-filled RSP, which consists of Class I and Class V RSP rock gradation at a 1:1 slope up to the roadway level. The soil-filled RSP will consist of layers of RSP with native material filled within the rock voids. The slope hinge point will be 3 feet from the existing edge of pavement. The corroded 42-inch diameter CMP will be repaired by lining it with a 36-inch pipe liner. The damaged embankment at the pipe outfall will be repaired with Class I, Class V, and Class III RSP. The project will require creek diversion system to isolate the creek from the work area, and to minimize water quality impacts to U.S. waters during construction. The diversion may include a gravle bag berm covered with plastic sheeting or similar items to isolate the streambed from the work area. If dewatering system requires pumping, all intakes will be completely screened with wire mesh not larger than 5 millimeters (0.2 inch) and preconstruction surveys will be performed by an agency-approved biologist. The existing pullout area at PM 20.5 will be used for equipment storage and stockpiling materials. Materials potentially containing contaminants, such as fuels, lubricants, oils, or solvents will be stored per Caltrans specifications. No storage of such materials will be removed after construction activities are complete. All permanently and temporarily disturbed areas will be restored to preconstruction conditions, where possible, and revegetated with appropriate native species.

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