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CC - Approval of Amendment to Existing Professional Services Agreement with California Watershed Engineering for Additional Design Services for Mesmer Low Flow Diversion Project, PR-005 in an Amount Not-to-Exceed $28,582 ($25,984 Base Cost with a 10% Contingency of $2,598)
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Meeting Date: January 28, 2019
Contact Person/Dept.: Lee Torres/Public Works Department
Phone Number: (310) 253-6457
Fiscal Impact: Yes [x] No [] General Fund: Yes [] No [x]
Public Hearing: [] Action Item: [] Attachments: []
Commission Action Required: Yes [] No [] Date:
Public Notification: (E-Mail) Meetings and Agendas - City Council (01/23/19);
Department Approval: Charles D. Herbertson, Director of Public Works/City Engineer (12/27/18)
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RECOMMENDATION
Staff recommends the City Council approve an amendment to the existing professional services agreement with California Watershed Engineering for additional design services for Mesmer Low Flow Diversion Project, PR-005 in an Amount Not-to-Exceed $28,582 ($25,984 Base Cost with a 10% Contingency of $2,598)
BACKGROUND/DISCUSSION
On March 26, 2018, Council approved the professional services agreement for civil design for the Mesmer Low Flow Diversion Project (Project), PR-005.
The Public Works Department’s Environmental Programs and Operations Division (PW-EPO) Staff is proposing a low flow diversion system that will divert dry weather run-off from Centinela Creek Channel into the Mesmer Pump Station where the run-off will be pumped into an existing sewer main for conveyance to City of Los Angeles’ Hyperion Water Reclamation Plant (Hyperion) for treatment. The Mesmer Sewer Pump Station is located at 5586 Mesmer Avenue, Culver City, CA 90230 adjacent to Centinela Creek Channel.
This required Project is one of three projects approved in the Time Schedule Order (TSO) to comply with the Ballona Creek Bacteria TMDL. The Project is jointly funded by Cities of Los Angeles, Beverly Hills, Culver City, Inglewood, and West Hollywood, the County of Los Angeles and Los Angeles County Flood Control District. The following three regional projects collectively comply with the final water quality based effluent limitations during dry weather as specified by the Ballona Creek Bacteria TMDL:
1. Low Flow Treatment Facility (LFTF) #1 Project at Ballona Creek;
2. Low Flow Treatment Facility (LFTF) #2 Project at Sepulveda Channel; and
3. Mesmer Low Flow Diversion Project at Centinela Creek.
Culver City is taking the lead in managing both design and construction of the Mesmer Low Flow Diversion Project with City of LA managing the LFTF #1 & #2 Projects.
Conceptual Design
Mesmer Low Flow Diversion (LFD) System was conceptually designed to divert dry weather run-off from Centinela Creek Channel into a proposed inlet constructed along the channel. The inlet will be connected to a new 15-inch diameter pipe that will convey the run-off into a new 13 feet deep concrete receiving sump. From the receiving sump, a new 15-inch diameter pipe will take the run-off via gravity flow into an existing sewer manhole that discharges to the existing sanitary sewer wet well. Both the sewer and dry weather run-off collected in the existing sanitary wet well will be pumped to the sanitary force main for conveyance to Hyperion for treatment.
The low flow diversion system was conceptually designed strictly using gravity flow. However, during design, there were concerns with operational failures to the proposed check valve that is designed to prevent backflow of sewage from the sewer wet well to the creek.
Therefore, to provide added protection from sewer overflows into Centinela Creek, staff is proposing to design a separate low flow diversion pump station upstream of the existing sanitary sewer wet well. The run-off diverted from the channel would gravity flow into the low flow diversion pump station. This would allow the captured run-off to be discharged from the low flow diversion pump station at a higher elevation inside the existing sanitary sewer wet well. The higher discharge point and the pumping system eliminates any potential of sewer overflows from entering Centinela Creek Channel through LFD System.
Request Additional Services
Staff is requesting additional design services to add the separate low flow diversion pump station upstream of the existing sanitary wet well, modifying the original design proposal that was based on gravity flow from the Centinela Creek to the sanitary sewer wet well and, which did not include any intermediate pump system design. The additional design services is required for mechanical and electrical design related to the separate low flow diversion pump station.
FISCAL ANALYSIS
The project funding is as follows:
|
PROPOSED PROJECT BUDGET |
|
Funding Source |
Amount |
|
Mesmer Low Flow Diversion CIP (43480000.730100.PR005) |
$180,000 |
|
Total Available Funds |
$180,000 |
|
Amount |
|
|
Design - CWE |
$129,805 |
|
Proposed Additional Work |
$28,582 |
|
Total Design Cost |
$158,387 |
The cost of the additional civil design services is in the total amount of $25,984. It is recommended that the City Council authorize the Public Works Director/City Engineer to authorize amendments for additional design work in an amount not-to-exceed $2,598 (10%) if necessary. There is sufficient funds in the Project budget for the additional civil design services.
ATTACHMENTS
None.
MOTION
That the City Council:
1. Approve an amendment to the existing professional design services agreement with California Watershed Engineering for additional design services for the Mesmer Low Flow Diversion Project, PR-005 in an amount not-to-exceed $25,984;
2. Authorize the Public Works Director/City Engineer to approve amendments to the agreement with California Watershed Engineering in an amount not-to-exceed $2,598 for additional design work;
3. Authorize the City Attorney to review/prepare the necessary documents; and
4. Authorize the City Manager to execute such documents on behalf of the City.