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 habitat would be changed if the tide gates would become ineffective.
The PAFP and tide gate structure provide significant flood protection benefits during lesser tidal events and, as mentioned above, the tide gates protect significant brackish marsh habitat. The tide gates have outlived their initial 50-year structural life and exhibit signs of aging such as spalling concrete and exposed reinforcement steel, as well as the very significant seepage problem that was addressed by an emergency project in 2012. This seepage may reoccur at any time.
To evaluate the initial Project objective, staff conducted a preliminary planning study for replacing the tide gate structures. The problem and alternatives evaluation of the Project identified a two-phased approach to improving the PAFB. The scope of this first phase will be to immediately repair the tide gate structure and ensure the hydraulic performance of Adobe, Barron, and Matadero Creeks.
The second phase scope of work will be to coordinate District resources during the intermediate term with ongoing external efforts that include the PAFB. These projects include the San Francisquito Creek Joint Powers Authority’s (SFCJPA) Strategy to Advance Flood protection, Ecosystems, and Recreation along the Bay (SAFER Bay) Project, the District’s South San Francisco Bay Shoreline Project, the South Bay Salt Pond Restoration Project, and projects under development by the City of Mountain View. The Project team expects that this intermediate term and collaborative project would likely result in a more efficient alternative to improve the PAFB and maintain the current level of flood protection in Matadero, Adobe, and Barron creeks. A Project Map is provided at Attachment 2.
The work in this Project will include dewatering of each cell of the tide gate, repairing spalled concrete surfaces, injecting epoxy into cracks in concrete, placing a polyester concrete overlay on the tide gates structure deck, and replacing the existing 36” chain link railing with a new 48” chain link railing at each side on existing deck.
Outreach to Bidders
As part of the District’s customary small and local business outreach, the following routine steps will be taken: the Notice to Bidders will be sent to approximately 27 plan rooms, 20 minority businesses, Chambers of Commerce and small business groups. In addition, the Notice will be sent to certified small business contractors and local and regional firms that have the appropriate license for this type of work. The Notice will also be provided to the Santa Clara and San Benito County Buildings and Construction Trades Council, which maintains contacts with at least 500 contractors and 70 union representatives, for distribution to their members.
Board Adoption of Plans and Specifications and Addenda Authorization
Board adoption of plans and specifications and Board authorization to advertise is recommended in order to proceed to bid the Project for construction. Authorizing the Designated Engineer to issue addenda during the bidding allows for modifications to the construction contract documents, if necessary, during the bidding period and before the contract is awarded.
Public Outreach
The District will lead the public outreach and communication for the Project and serve as the main Project contact for the community and media. The District will use a variety of outreach activities to keep the community informed of the Project progress and important milestones. Outreach efforts will include physical site and trail closure signage, social media Nextdoor posts as needed, website posts as needed, and coordination with the District’s partners at the City of Palo Alto, Bay Trail, Baylands Nature Preserve and Silicon Valley Bicycle Coalition. During construction, the outreach messages will focus on the Project benefits and impacts to trail and park users, and will be targeted to the surrounding neighborhoods and businesses.
Next Steps
If the Board approves the recommendations, staff will proceed to advertise for bids for Project construction. The next Board action would be for award of the construction contract, tentatively scheduled for July 11, 2017.
FINANCIAL IMPACT:
The estimated construction contract cost for the Project is between $270,000 and $330,000. Adequate funding for this contract is included in the FY 2016-17 budget, Project #10394001.
CEQA:
Staff has determined that the implementation of this Project will meet the requirements of the minor maintenance in-kind repair activity under the District’s Stream Maintenance Program (SMP). The construction of this Project has been included in the Notice of Proposed Work (NPW) to the permitting regulatory agencies for 2017 instream work season.
ATTACHMENTS:
Attachment 1: Notice to Bidders
Attachment 2: Project Map
UNCLASSIFIED MANAGER:
Manager
Ngoc Nguyen, 408-630-2035