Title
Environmental Management Director requesting ratification of her signature on Change Order 031-PW-06/07-BOS, CCO No. 1 with D & E Construction to provide additional geotextile material for the Union Mine Landfill 13.6 Acre Final Closure project.
RECOMMENDED ACTION: Approve.
Body
BUDGET SUMMARY: |
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Total Estimated Cost |
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$49,500 |
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Funding |
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Budgeted |
$ |
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New Funding |
$ |
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Savings |
$ |
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Other |
$ |
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Total Funding Available |
$49,500 |
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Change To Net County Cost |
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$0.00 |
Fiscal Impact/Change to Net County Cost: Funding for the Change Order is available in the FY 2007-08 CSA #10 proposed budget. There is no cost to the General Fund.
Background:
The closure for the 15.8-acre Class III Old Landfill at the Union Mine Disposal Site specified by the California Valley Regional Water Quality Control Board, Central Valley Region (CVRWQCB) in new Waste Discharge Requirements Order No. R5-2006-0020 must be completed by August 15, 2007. As part of the Final Closure Plan, which was submitted to the CVRWQCB on March 30, 2006, it was identified that 13.6 acres of the 15.8-acre Class III Old Landfill Area will receive final cover in the year 2007. The remaining 2.2 acres are schedule to be closed in the year 2040, the projected closure date of the Class II active disposal area.
Reason for Recommendation:
This closure requires the use of geosynthetic products, specifically a linear low-density polyethylene geomembrane liner, geocomposite drainage net and non-woven geotextile. The geotextile material is designed for use between the pre-existing soil sub-grade and geomembrane liner in places that the soil sub-grade is either unstable or unsuitable to physically meet against the geomembrane liner. The existing soil sub-grade was placed on the Union Mine Landfill closure area in approximately 1995.
On March 13, 2007, the Board of Supervisors approved the bid documents to purchase and install the Geosynthetics for the Final Cover, 13.6 Acre Class III Old Landfill Area, Union Mine Disposal Site project. On May 22, 2007, the Board of Supervisors awarded the Geosynthetics bid to the lowest, responsive bidder, D & E Construction, Inc.
The contract bid documents indicated that as little as zero square feet or as much as 592,500 square feet of geotextile material may be required for this project. Due to the soil sub-grade uncertainty and potential variation based upon twelve years of natural weathering at the site, the bid schedule required the bidder to submit a price per square foot based upon the quantity of 100,000 square feet as a benchmark.
As part of the Final Cover project, the 13.6 acre closure area was "grubbed and scrubbed" of all grasses, weeds, shrubs, etc. It was not until the completion of this phase could the soil sub-grade be fully examined. Upon analyzing the soil sub-grade it was determined 325,000 square feet of geotextile material would be needed due to suitability issues, specifically, the presence of numerous jagged rocks, and to avoid potential long-term damage to the yet-to-be installed geomembrane liner.
In order to meet the project deadline of August 15, 2007 as required by the California Regional Water Quality Control Board, a change order was issued and signed by the Director of Environmental Management. The Department is requesting the Board ratify the Director's signature on the attached Change Order request. The Change Order specifies an additional 225,000 square feet of geotextile material at $.22 per square foot, including installation. This is a $49,500 increase to the original bid amount of $624,637.50.
Action to be taken following Board approval: The Department will execute the attached Change Order.
Contact: Gerri Silva, Environmental Management Director
Concurrences: