Title
Recommendation to Accept the Work of NBC Construction and Engineering, Inc. for the Harbor Bay Isle Lagoon Improvement Project, No. PW 07-21-28.
In accordance with the California Environmental Quality Act (CEQA), this project is categorically exempt from further environmental review pursuant to CEQA Guidelines Section 15301 (Existing Facilities). (Public Works 31041520)
Body
To: Honorable Mayor and Members of the City Council
From: Jennifer Ott, City Manager
EXECUTIVE SUMMARY
The City of Alameda (City) issued plans and specifications for the Harbor Bay Island (HBI) lagoon improvement project on September 9, 2021. The construction contract was awarded to NBC Construction and Engineering in an amount not-to-exceed $344,683. The project replaced level sensors, control panels and made other improvements to restore the automated movement of water through the northerly lagoon system coincident with the tide. The improvements executed under the subject contract are complete and acceptable to staff. Staff is now recommending that the City Council accept the work.
BACKGROUND
The HBI lagoon system, located on the Bay Farm Island peninsula, was constructed in the 1970s. It forms a major component of the HBI community providing open space, aesthetic and recreational enjoyment for residents. The lagoon system also accepts stormwater drainage from the adjacent developed areas. The northerly lagoon extends from the San Francisco Bay at the west end to the San Leandro Channel at the north end, creating a narrow river-like waterway nearly two miles long. The basic operation of northerly lagoon is dependent on the normal San Francisco Bay tidal action which, through gate control systems located at each end of the lagoon, provide a degree of water movement from west to north while maintaining a desired water level in the lagoon.
Water circulation through the lagoon is critical for water quality. Constant circulation and exchange of water with the San Francisco Bay, periodic and spot treatments with algaecides and the control of stormwater run-off contamination are all required to maintain the overall ambience of the lagoon. The original design and construction of the gate control systems had automatic sensing of Bay and lagoon water levels, which controlled the degree the gates were opened or closed for water movement. Many years ago, the automation of water movement became inoperable. City staff manually controlled the gate levels to move water through the system. While this generally worked, it was inefficient, less precise and less effective at moving water through the system. This project restored the level sensing, logic and remote lagoon monitoring through the City’s System Control and Data Acquisition (SCADA) system. The project also replaced equipment at the end of its useful life and improves worker safety at each site. The system now has built-in alarms, redundancy and override manual operation to ensure reliability of the system.
DISCUSSION
The City issued plans and specifications for the HBI lagoon improvement project on September 9, 2021. The construction contract was awarded to NBC Construction and Engineering in an amount not-to-exceed $344,683, which included a 15% contingency. The project replaced level sensors, control panels and made other improvements to restore the automated movement of water through the northerly lagoon system coincident with the tide. The improvements executed under the subject contract are complete and acceptable to staff. The total actual cost was $315,548.35. Staff is now recommending that the City Council accept the work.
ALTERNATIVES
• Accept the work as presented.
• Do not accept the work and give staff alternate instruction.
FINANCIAL IMPACT
The project was budgeted in the Stormwater Management Capital Improvement Program (Project No. C31000) with funding from the Stormwater Fund (Fund 264). No additional appropriations are needed. There is no impact to the General Fund.
MUNICIPAL CODE/POLICY DOCUMENT CROSS REFERENCE
This action is consistent with the Alameda Municipal Code.
ENVIRONMENTAL REVIEW
In accordance with CEQA, this project is categorically exempt from further environmental review pursuant to CEQA Guidelines Section 15301 (Existing Facilities).
CLIMATE IMPACTS
The project increased the resiliency of the stormwater drainage system. It also maximizes water movement through the lagoon system, which generally leads to reduced chemical applications to control algal growth. Lastly, automation will reduce vehicle trips from the maintenance service center to the gate structures.
RECOMMENDATION
Recommendation to accept the work of NBC Construction and Engineering, Inc. for the Harbor Bay Isle Lagoon Improvement Project, No. PW 07-21-28.
Respectfully submitted,
Erin Smith, Public Works Director
Financial Impact section reviewed,
Margaret O’Brien Finance Director