PG&E has started work to replace a 12-inch-diameter high-pressure gas main between Ceres and Hughson.

The $50 million project calls for starting for trenching down Whitmore Avenue in the area of Ceres High School to replace an important gas line that serves Ceres, Hughson and Turlock.

City Engineer Toby Wells said the work will get interesting east of Mitchell Road where a horizontal directional bore that will go down 30 feet underneath the canal and come up east of Moore Road. The trenching will continue down Whitmore Avenue to Hughson, then south on Geer Road to Turlock.

Wells said the Ceres portion of the project should be done before school starts next month.

Richard Dye, PG&E's Government Relations Representative, said the goal is to install 10 miles of new pipeline from Ceres High School to Hughson before going to Santa Fe and Geer Road down to Turlock, and make the road surface appear seamless in the process.

PG&E is replacing gas lines in the state through a high pressure hydrostatic testing process to determine which of the older lines are at risk of rupturing and causing explosions like the one in San Bruno. Dye said PG&E's line down Whitmore Avenue to Hughson varies in age, dating back to the 1930s to the 1970s. Because it ranges in size from six to eight inches, it cannot accommodate "smart pigs," a robotic video camera to check line integrity.

"Given the age, it's more efficient for us to replace it than upgrade it," said Dye.

The larger size pipe will allow service to future food processing plants, he added.

The new line will be 12 inches in diameter and be planted 15 to 20 feet from the current line, which will be left in place in the interim because it supplies gas users in Hughson and Turlock. Once the new gas line is installed and used, the old line will then be abandoned and left buried in the ground.

Work is expected to end in October.

A similar replacement was recently completed near the Vintage Faire Mall.

PG&E must submit a traffic plan to the city that details when work will be done to minimize traffic impacts. Some disruptions can be avoided at night, which tends to slow down work, but PG&E will attempt to educate the public "before, during and after" the work takes place, he noted.

Dye informed the council that PG&E has plans to replace a gas line going west on Whitmore Avenue toward Morgan Road but not until next year.

PG&E has been in discussions with Stanislaus County and the cities of Ceres, Turlock, and Hughson since December.