LINE C-8 DRIANAGE BYPASS IN THE VICINITY OF 17130 FOOTHILL BLVD, CASTRO VALLEY, ALAMEDA COUNTY, ZONE NO. 2 PROJECT

LINE C-8 DRIANAGE BYPASS IN THE VICINITY OF 17130 FOOTHILL BLVD, CASTRO VALLEY, ALAMEDA COUNTY, ZONE NO. 2 PROJECT

The project is located along Zone 2, Line C-8, an underground flood control culvert that connects to an existing 24” corrugated metal pipe (CMP) through 17130 Foothill Blvd. in the unincorporated area of Castro Valley, Alameda County, California. The project would construct a 30” diameter underground reinforced concrete pipe (RCP) to bypass approximately 200 feet of the existing severely corroded 24” CMP. The existing corroded 24” CMP will be abandoned in place. The proposed bypass alignment would connect at the existing drainage inlet on the westerly side of Ehle Street, slope northerly along the Ehle Street right-of-way, turn west onto and through the northerly side yard, continue along the westerly and northerly portion of the park lot within 17130 Foothill Blvd parcel and reconnect at the existing drainage inlet on the easterly side of Foothill Blvd. The proposed bypass length is approximately 410 feet with approximately five (5) proposed storm drain manholes along the bypass alignment. The project would remove and replace approximately 40 feet of corroded 24” CMP within Ehle Street and approximately two (2) inlets, located on the west side of Ehle Street and Foothill Blvd. A small bladder dam or a cofferdam with a gravity or mechanical pumping system with pipes would be used to divert flows downstream. All Clean Water, Best Management Practices (BMP) would be used for the diversion of any flow downstream. Upon completion of the project, the bladder or cofferdams and all temporary pipes will be removed and normal water flows will be re-established. The project would install approximately five (5) clean out manhole boxes along the proposed C-8 bypass line. The project would remove approximately 3 (three) landscape trees, replace approximately 150 ft. of sidewalk, repave 160 ft. by 10 ft. in width of asphalt and add stripping and signage affected by the project. All landscape trees removed will be replaced in kind, near or at the same locations. All work will be performed within County road right-of-way, and on permanent and temporary easements to be obtained from property owner at 17130 Foothill Blvd to accommodate the project needs. The purpose of the project is to mitigate potential flooding due to severely corroded CMP and to restore culvert conveyance within the existing drainage system.

Hayward

Alameda

Unincorporated

Alameda