SUBJECT:
Title
Adopt Plans and Specifications and Authorize Advertisement for Bids for Construction of the Palo Alto Flood Basin Tide Gate Structure Improvements Project, Project No. 10394001, Contract No. C0630 (Palo Alto) (District 5).
End
RECOMMENDATION:
Recommendation
A. Adopt the plans and specifications and authorize advertisement for bids for the Palo Alto Flood Basin Tide Gate Structure Improvement Project (Project) per the Notice to Bidders; and
B. Authorize the Designated Engineer to issue addenda, as necessary, during bidding.
Body
SUMMARY:
The Palo Alto Flood Basin (PAFB) Tide Gate Structure Improvements Project was initiated following emergency repair work on the Palo Alto tide gates which was completed in September 2012. The repair work addressed water flow occurring beneath the tide gate structure which was originally constructed in 1956. The temporary repair arrested significant under flow; however, additional and permanent improvements are required to avoid future loss in level of service which could result in fluvial flooding in the lower reaches of Matadero, Adobe, and Barron creeks and impacts to wildlife and aquatic habitats in the flood basin.
The PAFB Tide Gate Structure was built in 1956. The purpose of the structure is to control the downstream water surface elevation for Matadero Creek, Adobe Creek, and Barron Creek, which all drain to the PAFB. The PAFB controls the downstream boundary condition (starting water surface elevation) for these creeks by keeping the high tide out and allowing the Basin to empty out during the twice daily low tides. Of the current 16 tide gates, 15 are operated by the District and one is operated by the City of Palo Alto. The latter is operated to allow some tidal inflow to the Basin, subject to an elevation limit to provide PAFB flood protection capacity. Since Bay waters have limited access to the PAFB, it has developed a brackish habitat, different from adjacent saltwater wetlands. This habita...
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