A contract increase of $440,157 for a new cell at the landfill was approved during Tuesday's Watertown City Council meeting.
Dan Hart Patrol Services was awarded the project with an original bid of $1.79 million, which was 18% below the engineer's estimate. However, during the cell excavation, a large area of poor soil and an underground spring were uncovered. With the extra money approved, the overall cost is now about $2.23 million.
Houston Engineering is overseeing the construction of the new landfill cell. The engineering firm also worked on the construction board for the development of landfill cells five and six.
Dennis McAlpine, a civil engineer with Houston Engineering, explained that the cell's baseline must be raised 4 feet to increase the density of the cell's liner.
"There is a combination of highly organic and gravel-type material and then a saturated clay. It is a highly fractured clay," said McAlpine.
The construction of the cell requires the removal of the undesirable soil and proper drainage for the underground spring.
City Councilman Michael Danforth asked if soil borings were taken at the site prior to awarding the contract. But even with soil borings, there is still a chance that the soil conditions can be missed, McAlpine said.
"We did a very limited boring exercise in 2021," he said. "We did the borings, but just happened to have missed it."
With soil conditions in the other landfill cells not being a problem, the organic material and underground spring surprised contractors.
"The facility has constructed six cells out there," said McAlpine. "There was no indication that we would have had to do an elaborate study."
Another reason for not doing a more extensive soil boring is how close the new cell will be to the first cell.
"We don't have good records on cell No. 1," said City Engineer Heath VonEye. "What we didn't want to do is go poking holes in the ground through soil borings and then puncture cell No. 1."
Funds to pay for the new cell will come from a $400,000 solid waste management state grant, a $1,428,000 clean water state revolving fund loan and a $212,000 American Rescue Plan grant, totaling $2.04 million. The remaining $193,500 will come from the landfill's unrestricted cash balance.
Pavement project over budget
The 2022 pavement rehabilitation large patch project was over budget by $27,364 when it was bid. Now that number has grown by another $13,528, prompting the city council to approve a contract change that pushes the overall cost to $290,792.
The engineer's estimate was $152,361.
The pavement rehabilitation project will repair roughly 40 city blocks of asphalt throughout Watertown.
"We bid this project on a very conservative level for a couple of different reasons," said VonEye.
They include attempting to keep costs down and using any rollover funds for other projects, he said.
"Like the Third Avenue bridge and reconstruction project that came in over budget. We needed to keep the ... fund balanced for 2022," said VonEye.
While the pavement rehabilitation project will cost more than estimated, VonEye said the asphalt cost is competitively priced.
"We felt this was a very competitive bid for the unit pricing," he said. "We did not negotiate a lower unit price on the asphalt."
The engineering staff has proposed using capital improvement fund money to offset the extra cost and keep funds balanced.
This article originally appeared on Watertown Public Opinion: Street maintenance, landfill cell costs increase, costing Watertown $453K