SOUTH BRISTOL – State transportation officials have gone back to the drawing board as they design a new bridge for the waterway known as “The Gut,” the result of lobbying by a group of residents who didn’t like plans that called for bridge sections rising high above the road when open.

The residents hired a prestigious Boston architect to design a competing project, and presented it to the state in January, asking officials to reconsider their previous concept.

Department of Transportation officials met with townspeople in July, and unveiled plans for a hinged bridge that would be 67 feet high when in the open position.

Some complained it would dwarf nearby buildings and destroy the character of the quaint village. The current 1933 “bobtail” swing bridge opens thousands of times each year to allow nautical traffic to pass between the Damariscotta River and Johns Bay.

And on land, vehicle traffic stops on Route 129 to allow boat traffic through. The swing bridge connects the peninsula to Rutherford Island, home to many summer residents.

The South Bristol bridge is one of the busiest movable spans in the nation, due to its low profile in the water, DOT has said, opening even to allow kayakers and small boats through. At high tide, seawater makes contact with the underside of the bridge deck for two to three hours, which has led to its demise. It is beyond repair, according to the state.

The new bridge will be designed for a minimum of 20,000 openings per year. And because the machinery that runs the bridge will be located above the road, it will not be subject to flooding.

Seeking a better design for the bridge, the group of residents hired award-winning architect Miguel Rosales, who was lead architect on the Leonard P. Zakim Bunker Hill Bridge over the Charles River in Boston. In about a month, Rosales Partners designed a bridge that meets the state’s requirements, yet also is visually appealing to residents because of its smaller scale, residents believe.

Both bridge plans carry an estimated price tag of $3.8 million, and have similar construction timelines and future maintenance expenses. However, the Rosales bridge rises just 36 feet above street level when open.

In a rare marriage of public and private interest, DOT engineers and architects met with Rosales and the residents, and now are carefully reviewing the Boston architect’s design, according to DOT spokesman Ted Talbot.

“This is very unique,” Talbot said of DOT’s decision to reconsider its plan. “These are primarily summer folks who had the means and the willingness to hire a Boston architect.”

Talbot said talks are underway at DOT about the best way to incorporate the positive aspects of the Rosales design into the state’s plan.

“It certainly is a lower profile bridge, and they are looking at it from an engineering standpoint because hydraulics and weather and winter and water doesn’t work,” he said, noting DOT would prefer using counterweights.

A new plan from the state should be ready in six to eight weeks, Talbot said. He predicted this unexpected redesign will not delay the project, which was going to be advertised to bidders in mid-April, with work commencing this summer.

“It really shouldn’t affect the timeline, things are still on track,” the DOT official said.

Once a new plan has been developed, it will be taken back to townspeople at another public hearing in South Bristol, he noted.

“We’re always willing to talk,” Talbot said.

Resident and historian Dave Andrews has been actively involved with the ad-hoc bridge group. He declined to say how many members are in the group, how they stay in touch and who they are. He did confirm Rosales was hired with private money from the group and that members are pleased to have a seat at the table on this important issue.

“The DOT has been very responsive, and the bridge group is very pleased that they took our plan seriously,” Andrews said. “A working relationship has developed, and I believe this is a very unusual situation for DOT to be in.”

The group has set up a web site, called “Build The Right Bridge” (southbristolbridge.org) which details the two plans and encourages visitors to click a link that urges DOT to adopt the Rosales plan.

The web site calls the DOT proposal “completely inappropriate and out of character for our small fishing village.” To date, the site indicates 599 web visitors contacted DOT to voice concern. The town has a population of about 900.

Andrews said the group appreciates DOT’s willingness to go back to the drawing board.

“I’m sure it wasn’t easy coming back and reconsidering something they have spent a lot of time and money on,” he said.

At a January meeting, state officials met with Andrews and others as the Rosales plan was presented, and DOT seemed to support its fundamental shape and concept.

A member of the South Bristol Historical Society, Andrews said the new bridge will be the fifth in that location. He noted a new “lift bridge” will recall the bridge that preceded the existing one, with a deck that lifts up rather than swings open.

The notion of having a modern bridge to replace the current 80-year-old model does not bother him, however.

“As an historian, I’m interested in change in the village. History is change,” he said. “Everybody in town wants a good, working bridge. The swing bridge is getting very tired.”

The two plans are similar in timeline and cost. But the Rosales plan eliminates the large arms and an overhead crossbeam that had been designed by DOT architects Clough, Harbour and Associates. It provides extra clearance between the bridge deck and the surface of the water (four feet instead of three), which could decrease the number of bridge openings, the plan notes.

It also adds a sidewalk with railings to enhance pedestrian safety, and features a control house for the bridge operator that is aesthetically compatible with the surroundings, according to the proposal.

The state plans to wait until the sturgeon migration is complete, most likely in November, then close the channel to navigation and build a temporary bridge. Workers would remove the existing bridge and the superstructure for the new bridge, which will be built off-site, would be brought in by barge and put into place. The channel would be closed for seven to eight months. No taking of private land has been proposed in either plan to date. The bridge is expected to last at least 75 years.

The state also intends to rebuild 4,250 feet of road along Route 129 and widen the travel lanes.

With the bridge, road improvements and new control house, the estimate is almost $8 million. Of that, DOT has said the federal government will pay 80 percent, the state will pay 20 percent and there is no cost to the town.

South Bristol is home to an active lobstering and groundfishing fleet, as well as recreational boating enthusiasts. The project is scheduled to be completed by fall 2014, or spring 2015 if there are delays.