By Kristi DYES
The Union Democrat
Design work is progressing on the Jamestown Landfill closure and construction could begin this summer, county officials say.
Tuesday, the Tuolumne County Board of Supervisors unanimously approved a $687,380 contract amendment with Oakland-based Geomatrix, Inc., a geotechnical engineering firm, for ongoing work on the landfill's final closure design.
The increase will cover all of the firm's work up to the point of construction, County Administrator Craig Pedro said, after the meeting.
There is no final estimate on the construction project's cost, but the highest number at this point would be $7.4 million including the approved contract amendment for Geomatrix, Pedro said.
"We hope it will be less," he said. "We'll know more about the estimate probably next month."
Pedro added that the county hopes to have bids for the project by late May or early June and start construction in late June or July in order to meet the California Regional Quality Control Board's final closure deadline of Dec. 31.
The board originally approved a $239,400 contract with Geomatrix last May for design repairs on the western slope of the landfill cover, which had begun slipping. It was amended in December to $326,521 after additional failures were discovered on the eastern slope.
After the California Regional Quality Control Board determined the landfill closure would need to be redone, Geomatrix designed a new one that was approved by both the county and water board.
Geomatrix's final design will include:
Constructing a new final cover
Abandoning current landfill gas vents and constructing new ones
Dismantling cover surface drainage systems and constructing a new one
Constructing a 20-foot-high soil buttress on the landfill's eastern side
Moving garbage to other locations within the landfill to create flatter slopes
Supervisor Teri Murrison asked if the board would have to consider other contract adjustments in the near future.
"There are none at this time," Peter Rei, Tuolumne County director of public works, said. "With the nature of construction being as it is, that could change."
The money for the increase will come from the Solid Waste budget, according to Rei's memo.
The landfill was first closed in 2005 and the original design was done by Diamond Bar, Calif.-based Bryan A. Stiratt and Associates. So far, more than $7 million has been spent on the closure and related costs.