PRAIRIEVILLE — The road contractor hired to widen La. 73 in Ascension Parish to three lanes has proposed shifting the location of sewer lines planned along the highway to speed up the project, a state highway official said Thursday.

The Louisiana Department of Transportation and Development is planning to widen La. 73’s two traffic lanes from 11.5 feet to 12 feet and install 6-foot shoulders on each side along with a third middle lane.

The project is bid to cost $15.5 million, including $3.2 million the parish plans to chip in for the sewer lines, DOTD officials have said.

The sewer lines are required because the road project involves enclosing open ditches, which would prevent treated effluent from being sent to the future drainage pipeline. The parish is also planning a regional sewer system.

The possible shift in plans came to light during a DOTD open house session at St. John the Evangelist Church Community Center as Aaron Elisar, DOTD project manager for La. 73, reviewed plans with residents.

Several people who filtered in and out of the hour-and-a-half open house wanted to see how the widened road would affect their land or their trees.

Though La. 73 winds through one of the parts of Ascension that recorded the fastest growth during the past decade, the roadsides retain many scenic live oaks.

David Oubre, 67, who lives along La. 73, spoke with Elisar about how utility relocations might affect the roots of a large old oak on his property and how drainage would flow past the tree into underground lines.

George Bonfanti, owner of Oak Lane Memorial Park cemetery, voiced concerns about his trees after Elisar discussed the proposal to move the sewer line.

“I got 160 live oaks there, and I want to keep every one,” Bonfanti said.

Plans to widen La. 73 between Airline Highway and Interstate 10 call for installing gravity-fed sewer lines and a force main underneath the center of La. 73, Elisar said.

He explained that plan means contractors would have to work in limited space between two lanes of traffic.

Elisar told landowners that Barber Bros. Contracting Co. LLC is considering a plan to move the sewer lines to the east side of La. 73 and parish officials are reviewing the idea.

Under that plan, Elisar explained, contractors could keep two lanes of traffic together instead of having lanes separated by a construction zone.

Utility work is under way, and full construction should begin in about a month. It will start with laying sewer and drainage pipes, DOTD officials said. The project is due for completion in the summer of 2013.