Questions and Answers About 48-inch Force Main Reliability Improvement Project

The South Bayside System Authority (SBSA) began its long-anticipated 48-inch Force Main Reliability Improvements Project: Unit 1 – Maple Street to Bair Island on June 3, 2013. This segment is expected to take at least 12 months to complete. Detailed information about the project is available at (For answers to questions regarding SBSA’s project not covered below, please contact SBSA representative Duane Sandul at (650) 585-2181 or, or visit the website above; email questions are helpful).  

Here are answers to frequently asked questions about Unit 1 and the impact on Maple Street and Bair Island Road and surrounding areas.

What specifically is being done? 

  • Installation of 48-inch diameter high density polyethylene pipe below grade using shored open-trench and microtunneling construction methods. The open trench portion is identified as Reach 1, which is a northeasterly alignment approximately 1,000 feet long between the southern end of Maple Street near the San Mateo County Women’s Correctional Facility and microtunneling Jacking Shaft 1 near the Docktown entrance on Maple Street. 
  • Installation of 72-inch diameter steel casing below grade using microtunneling (trenchless) construction followed by installation of 48-inch diameter high density polyethylene sanitary sewer force main pipe and two (2) 3-inch diameter high density polyethylene conduits within the steel casing for fiber optic communication between pump stations and the main wastewater treatment facility. Construction of trenchless segments (microtunneling) will require the construction of jacking and receiving shafts at various locations along the alignment. These are:
    • Jacking Shaft 1: Located in Maple Street near 1548 Maple Street.  
    • Receiving Shaft 1: Located at the east end of the USFWS parking lot off of Bair Island Road.  
    • Jacking Shaft 2: Located on the property owned by the USFWS near the new pedestrian bridge, approximately 150 feet east of Uccelli Boulevard.  
    • Receiving Shaft 2: Located on the Inner Bair Island levee at the southeast corner of the levee.    

Will the project impact Maple Street access? 

  • Maple Street will remain open to vehicle traffic at all times throughout the duration of the project.  
  • The contractor will maintain a minimum of one12-foot wide traffic lane along Maple Street southwest of Jacking Shaft 1 at all times and will provide traffic control that provides for safe flow of traffic without undue delays. 
  • The contractor will plan and construct the pipeline improvements so that vehicle access from Maple Street to all residences, businesses, and institutions accessible from Maple Street is maintained at all times. 
  • During pipeline construction most, if not all, parking along Maple Street will be eliminated due to the very narrow road corridor and the need to allow for vehicle access along the road. Proper notification as well as proper signage will provide direction to motorists using Maple Street. 
How will the project affect Bair Island Road and surrounding areas?

  • Access to the U.S. Fish & Wildlife Service (USFWS) parking lot adjacent to the Villas at Bair Island Marina will be accessible throughout the project via a temporary access road. The contractor will post signs directing motorists wishing to use this parking lot. One of the connections to the existing Villas property parking area will remain open as well. Other than this, the project will not impact or encroach onto the Villas property. The USFWS parking lot will be used for project trailers, equipment, and supplies from approximately June 2013 through April 2014.    
  • Although the actual USFWS parking lot construction work will not take this whole time, the majority of the USFWS parcel will be used as the staging/storage area for the Redwood City portion of the project. SBSA does not foresee the 48-inch FM project to create any obstructions to the road other than increased truck traffic. 
  • Additionally, SBSA is aware of other construction in the area neighboring the Villas. The Pauls Corporation has installed a bypass road in order to modify the utilities in Bair Island Road for the neighboring One Marina Development. All traffic accessing the USFWS parking lot, The Villas, and Pete’s Harbor will need to use the bypass road until the utility work in Bair Island Road is completed.  
What about access to Inner Bair Island Pedestrian trail during pipeline construction? 
  • The USFWS Don Edwards San Francisco Bay National Wildlife Refuge opened a new pedestrian bridge that allows visitor access on Inner Bair Island in Redwood City on April 22, 2013. The bridge permits entrance to a one-mile loop trail around the southeastern portion of Inner Bair Island, known as Area D. Visitors are currently able to park in the refuge parking lot on Bair Island Road, access the pedestrian bridge from nearby Uccelli Boulevard, and cross onto Inner Bair Island to access the Area D trail.  
  • In coordination with USFWS, SBSA will be installing a new 48-inch force main pipe along the entire western levee of Inner Bair Island between approximately June 1, 2013 and December 31, 2014. During this period, there will be controlled public access to the levee on the southern side of Area D.  
  • In conjunction with the Refuge’s ongoing clean fill material import to the Island, SBSA and the USFWS will take precautions to ensure public safety during construction of the Area D levee and 48 inch force main project. Access to the northern and eastern portions of the trail (approximately 0.6 miles) will remain available to visitors during construction; however, access to the southern portion of the Area D trail will experience intermittent closure. Temporary fences will be installed to provide safety zones during active construction periods. If construction activities are inactive for extended periods of time SBSA will open these areas to allow visitors to access more of the Area D trail.  

See a visual map showing public access (490 KB, pdf) 

Where will the pipeline contractor access Inner Bair Island for its project component there? 

  • Access to Inner Bair Island for construction of the pipeline improvements, including Receiving Shaft 2 and 48” Force Main Reach 4, will be via the gated access road at the north end of Whipple Avenue.   
  • Access to the site of Receiving Shaft 2 from Whipple Avenue requires crossing SBSA’s existing shallow-buried 48-inch diameter reinforced concrete sanitary sewer force main which is susceptible to damage from vehicle and construction equipment at-grade loading. The existing force main will be crossed only via the existing temporary bridge located on Inner Bair Island immediately north of the north end of Whipple Avenue. 

Are there other projects going on at Inner Bair Island?

It should be noted that the following construction in the vicinity the pipeline project is occurring concurrent with the construction of this project. This includes:

  • Construction of the Bair Island Restoration – Inner Bair Project (Restoration Project) by others for the U.S. Fish and Wildlife Service. Access onto Inner Bair Island is shared with the contractor for the restoration project. This includes use of the gate and access road at the north end of Whipple Avenue and the temporary bridge across SBSA’s existing sanitary sewer force main.   
  • The restoration project includes significant earthwork on Inner Bair Island including earthwork in the vicinity of Receiving Shaft 2 and the access route from Whipple Avenue to the site of Receiving Shaft 2. 
What about noise and vibration?

  • Noise Control Plan: The pipeline contractor will prepare a noise control plan prior to the start of construction to minimize construction noise levels as low as practical. 
  • Noise Barriers: The pipeline contractor will install temporary noise barriers to shield noise from microtunneling equipment at the shaft locations from residents and business near the construction areas. 
  • On Maple Street where vibratory pile driving will occur, the contractor is performing a pre-construction crack survey documenting existing conditions of buildings within 75 feet of the construction. This survey applies, but is not limited to, the following buildings: San Mateo County facilities at 1580 Maple Street and a multi-unit warehouse building at 1548 Maple Street. During construction on Maple Street, the contractor will monitor ground vibration levels outside buildings within 75 feet of the project area to confirm vibration levels are below the allowable level of 0.3 inch/sec PPV. If vibration levels exceed the allowable level, the contractor will complete a post-construction crack survey and repair any additional cosmetic damage resulting from the project. 
What are project working hours?

  • Construction will be allowed only between the hours of seven (7:00) a.m. and seven (7:00) p.m. on weekdays. When approved in advance by SBSA and the City of Redwood City, construction may be extended to include weekends and holidays but shall be limited to the hours between seven (7:00) a.m. and seven (7:00) p.m. on Saturdays, and nine (9:00) a.m. and six (6:00) p.m. on Sundays and holidays, unless other working hours are approved by SBSA in writing. 
  • In accordance with CEQA Mitigation Measures, truck traffic is limited to the hours of 7:00 a.m. to 7:00 p.m.  

Will the pipeline construction result in turning off my electricity, water, or sewer services?

There are no planned interruptions in the area along Uccelli Boulevard and Bair Island Road. Along Maple Street the contractor will be replacing both the existing sewer and water mains due to their age. When this work occurs there will be temporary disruptions to service in order to not only remove the existing line but to also connect the services to the new pipes. SBSA has retained a construction management firm to watch over all of the work. They, along with the contractor, will provide notification of upcoming service interruptions well in advance and also the day before the disruption occurs to that affected parties can plan for this. These disruptions will be temporary and will be as minimal as possible.