TO:
Honorable Mayor Powell and Members of the City Council
THROUGH:
David N. Carmany, City Manager
FROM:
Jim Arndt, Public Works Director
Steve Finton, City Engineer
SUBJECT: Title
Plans and Specifications for the FY2012-2013 Gravity Sewer Main Rehabilitation Project Including Sewer Spot Repairs at 34 locations in Areas 1, 2, and 3 (bounded by Manhattan Beach Boulevard, Ardmore Avenue, Aviation Boulevard and the Southerly City Limit) and Sewer Main Replacement in 11th Place from Ardmore Avenue to Highview Avenue.
APPROVE
Body
____________________________________________________________________
RECOMMENDATION
Staff recommends the City Council approve the plans and specifications and authorize the City Manager to solicit construction bids for the Fiscal Year 2012-2013 Gravity Sewer Main Rehabilitation Project.
FISCAL IMPLICATIONS:
Sewer Enterprise funds in the amount of $900,000 have been appropriated by City Council for this project through the Fiscal Year 2011-12 and Fiscal Year 2012-13 Capital Improvement Budget. Total expenditures are anticipated to be $600,326 leaving an anticipated balance of appropriations in the amount of $299,674. A summary of appropriations and anticipated expenditures in tabular format is provided in Attachment 1.
BACKGROUND:
City Council has committed to an accelerated infrastructure investment program. Increases in sewer rates have generated funding needed to make the important infrastructure improvements. In 2008 and 2009, 53% of the City's 81.6 miles of sanitary sewer mains were inspected using closed circuit television. In 2010 an additional 22.8% were inspected. These closed circuit television inspections allow staff to pinpoint problems in sewer mains such that spot repairs can be performed in lieu of full pipeline replacement. The plans and specifications include spot repairs at 34 locations in the Hill and southeast areas of the City and full main replacement of the segment of the sewer main in 11th Place from Ardmore Avenue to 250 feet east (see map, Attachment 2).
On April 17, 2012, City Council awarded a contract to VA Consulting in the amount of $64,982 to prepare plans and specifications for this project. The plans are complete and ready to be advertised for construction bids. If approved, bids will be solicited and will be opened in early January. Construction will begin in early March 2013. This project is being coordinated closely with the current water main replacement project in the same area. A public meeting will take place in December to introduce the project to the neighborhood and to hear concerns the residents may have.
DISCUSSION:
Sewer main rehabilitation strategies are selected based on the type, extent and location of deterioration. Below are the implementation strategies which were considered.
Spot Repairs - Sewer mains with localized structural problems only are candidates for spot repairs. Spot repairs consist of digging down to the deteriorated sewer main, replacing broken segments of pipe then backfilling and restoring surface improvements. This alternative is the most cost effective and durable alternative and can be completed in two to five days depending on the depth of the sewer to be repaired. This method was used successfully on the Fiscal Year 2010-11 Gravity Sewer Rehabilitation Project completed in 2011 and is recommended again for use on the Fiscal Year 2012-2013 Gravity Sewer Main Rehabilitation Project.
Slip Lining - sewers that are in good structural condition but have significant root intrusion or fine cracking are candidates for slip lining. Slip lining is a trenchless method of rehabilitation that consists of inserting a thin interior lining into an existing sewer pipe to provide a new leak-free interior surface. This method is relatively inexpensive, but is not as durable as a new pipe installed via a spot repair. This method can be completed in a single day.
Full- Replacement - Full pipeline replacement is required when sewers have structural deterioration throughout or have significant grade deficiencies. This method is the most costly and disruptive to the neighborhood and is selected only when the other alternatives are not feasible. This alternative requires months to complete.
Plans and Specifications
Plans and specifications for the 2012-2013 Sewer Main Rehabilitation Project are available for review in the City Clerk's Office at City Hall.
Attachments:
1. Tables 1 & 2: Funding and Anticipated Expenditures
2. Map of FY2012-2013 Sewer Main Rehabilitation Project