It won’t be like it was five years ago, city officials promise.

But some downtown business owners are casting a wary eye at work planned for this spring and summer to replace decades-old water lines under downtown streets. They remember too well the disruption caused in 1999, when a massive sewer replacement project closed Ninth Street and split downtown with open trenches for much of the summer.

“I think it will be a bit of a hardship, to be honest,” said Steve Buren of 7th Heaven, 1000 Mass., which sells CDs and futons. “It’s kind of a double-edged sword. I know the work needs to be done. Those water lines are 100 years old.”

The work scheduled to begin April 19 and continue through the summer will be along 10th, 11th and Vermont streets. And this year, the city says, only one lane of traffic at a time should ever be closed along the streets. The work will be done on a section-by-section basis, rather than closing all three of the streets at a single time.

“It’s not a cataclysmic close down,” Assistant City Manager Dave Corliss said Friday. “It’s a lane close down.”

City Manager Mike Wildgen agreed.

“There should be traffic on one side of the street, in most cases,” Wildgen said.

Another inconvenience: Water service occasionally will be disrupted at downtown businesses while the work is being done.

“Every attempt will be made to accomplish this in a short time period, and residents will be notified in advance when their water service is scheduled to be disrupted,” city officials said in an unsigned memorandum to downtown merchants.

The $563,000 project is part of a four-year phased project of replacing the water lines downtown with newer and bigger models. Emco Construction Inc. is the contractor; work will be done from 8 a.m. to 5 p.m. weekdays.

Last year, the work closed down street lanes along Vermont Street in front of the Lawrence Chamber of Commerce and on Eighth Street in front of the downtown fire station.

“That was a little disruption … but nothing major,” said Maria Martin, executive director of Downtown Lawrence Inc.

But she added of this year’s project: “It will affect quite a number of people when this happens.”

City officials say they’ve sent letters to downtown merchants and scheduled meetings to explain the project. The next meeting is scheduled for 1 p.m. Wednesday in City Hall, Sixth and Massachusetts streets.