Chris Caskey, The Union Democrat

The East Sonora Bypass project is moving along through the winter, but a state regulator is warning that the construction is causing too much erosion.

The Central Valley Regional Water Quality Control Board has cited Caltrans and contractor Teichert Inc. with two violation notices since Dec. 20 that could lead to a major fine over runoff at the site. The violation notices allege inadequate erosion protections have led to unlawful amounts of sediment discharged into local waterways.

According to Caltrans, steps are being taken to control erosion coming off of the bypass construction site. But water board spokeswoman Wendy Wyels said the project is still not complying with regulations, and an investigation is underway to determine just how severe the alleged violations are.

"They have tried to address it in some areas," she said on Wednesday. "But overall they are still in violation."

According to the citations dated Dec. 20 and Jan. 18, state water board staff have visited and inspected the site multiple times dating back to October. Inspectors allegedly found a lack of erosion and sediment controls and a "significant" amount of erosion as well as turbid, sediment-filled water in local waterways. According to the violation notices, this was especially true after rain at the portion of the project nearest to Mono Way.

The water board is requiring Caltrans and the contractors to bring their erosion controls up to code and also monitor and report pollutant levels, according to the citations. No fine has been issued, and Wyels said she couldn't discuss specific amounts or what would trigger or prevent a fine. But she said it could reach into the "millions" if a fine is issued.

Water board staff has subpoenaed extensive documents and will likely review them into the summer, she said.

"We're extremely concerned," she said.

On-site, crews have been laying out large plastic covers on disturbed ground to limit erosion and runoff, Caltrans District 10 spokesman Steve Gonzalez said. The plastic is visible from Highway 108, and will likely remain at least through the winter.

Gonzalez called runoff issues "typical" for a project like this one.

"What we found out is that, for a project like this in a mountain terrain, these issues … the runoff issues happen," he said.

Crews are working on the second of three phases for the East Sonora Bypass. This phase, when complete, will run from Peaceful Oak to Via Este Road.

While most of the heavy construction took place in the summer and will continue during the next traditional construction season, crews have continued bridge construction and other work and maintenance.

Once all three phases are completed, the entire bypass is expected to run from Sanguinetti Road in Sonora to the four-lane stretch below Twain Harte grade.