Tuolumne County’s new jail likely will not be completed until late 2019.

County staff has proposed changing the date for contractors to bid on the contract to Oct. 24, move the start of construction from January to March, and extend the construction timeframe from 18 months to 20 months.

Starting construction in the middle of winter would require the contractor to take more costly measures for preventing stormwater runoff and erosion from the project site off Old Wards Ferry Road in Sonora, said Deputy County Administrator Maureen Frank.

“That cost would then come down to the county,” Frank said. “I’d rather have the money go into the construction of the facility and not mitigation measures if I can help it.”

The six-acre site is located near Sullivan Creek and part of the Law and Justice Center campus that includes the Mother Lode Regional Juvenile Detention Facility.

Frank said the $39 million estimate for construction includes a cushion for possible increases in price, so the delays are not expected to cost the county more.

One of the reasons for moving the bid date from next Wednesday to Oct. 24 is to give the contractors time to recalculate their proposals, Frank said.

“They were basing their proposal off of starting in January,” Frank explained. “Now that we’re changing the scope of work, they need to go back and redo all of their numbers.”

The county learned the hard way about the pitfalls of starting construction in the middle of winter last year when stormwater flowed into Sullivan Creek from the Law and Justice Center.

State water regulators alleged that contractors working for the county failed to put adequate controls in place to prevent the sediment-laden water from flowing into the creek.

County leaders agreed to a $131,000 settlement with the Central Valley Regional Water Quality Board and vowed to seek reimbursement from the contractor, F&H Construction.

In July, county officials asked the board to consider delaying the start of construction until next year, but the board urged them to continue pressing forward for as early of a start as possible.

The overall cost of the jail is estimated at about $42 million, with $33 million of the construction costs being covered by two state grants. The county plans to pay for the difference largely through a mix of internal and external borrowing.

At a proposed 62,000 square feet, the new jail would be nearly twice the size of the existing one at 175 Yaney Avenue in Sonora that’s been criticized as antiquated, cramped and increasingly unsafe for inmates and staff.

There would be room for 230 beds at the new jail, up from 147 at the current jail.

The Tuolumne County Board of Supervisors is scheduled to consider approving the changes to the project timeline during a meeting that starts at 9 a.m. Tuesday in the board’s chambers on the fourth floor of the County Administration Center, at 2 S. Green St. in Sonora.

Contact Alex MacLean at amaclean@uniondemocrat.com or (209) 588-4530.