AUGUSTA – A state panel is recommending replacing a failing bridge on the Allagash Wilderness Waterway with a longer, higher span that incorporates new building technology developed by University of Maine engineers.

Henderson Brook Bridge near Round Pond is used by logging trucks carrying an estimated 150,000 tons of timber annually. Another 20,000 recreational visitors to the area also use the bridge yearly. But nearly 40 years of heavy use and severe winters have taken a toll on the bridge.

Sen. John Martin, who helped lead a panel examining replacement options for the bridge, questioned Thursday whether the span will survive the winter and spring.

“The bridge is worse now than it was five weeks ago or six weeks ago,” Martin said. “You can actually see further deterioration.”

Panel members voted Thursday to recommend building a new bridge adjacent to, but slightly downstream from, the existing bridge. The proposed bridge would be more than 200 feet long, versus the current 170-foot span, and stand about 3 feet higher.

Lengthening and heightening the bridge will allow engineers to place the abutments outside of the normal high water mark, thereby increasing the water flow area and reducing the risk of damage from ice flows.

The panel endorsed a proposal developed by researchers at UMaine’s Advanced Engineered Wood Composites Center to construct two piers out of steel I-beams and concrete encased in a glass fiber and polymer resin composite.

Eric Cassidy, a structural engineer with AEWC, said the composite is comparable to steel in terms of strength. But the composite can be dyed and textured to resemble wood. The sides of the bridge visible to river users would also be covered with wood from native trees to blend better with the surroundings.

The panel also recommended the state continue talking with AEWC staff about using high-tech wood products for the planking. But several members raised maintenance and durability concerns since the bridge must withstand trucks weighing in excess of 200,000 pounds driving over the bridge in winter with chains on their tires.

The timber industry is expected to pay to replace the state-owned bridge, which could cost more than $1 million. But Martin said partnering with UMaine to build a first-of-its-kind bridge could help the state garner federal funds for the project.

The group plans to file a final report with the Legislature’s Agriculture, Conservation and Forestry Committee on Jan. 29.

No one spoke during a public hearing on the draft recommendations. Nonetheless, the group has its critics.

The thought of rebuilding a bridge in the Allagash angers some environmental and conservationist groups who believe the state should be removing manmade structures from the federally designated “wild and scenic” waterway.

Several environmental organizations declined to appoint representatives to the panel and, instead, urged the state to move the bridge outside of the waterway.

An economic impact study conducted by panel members predicted moving the bridge would cost the timber industry $562,000 annually in additional transportation costs while eliminating a local crossing altogether would cost the industry nearly $1.2 million.

But Jym St. Pierre with RESTORE: The North Woods and Citizens to Protect the Allagash, dismissed the economic study as biased.

St. Pierre said the panel failed to consider the benefits of protecting wilderness or whether a new bridge in that location would meet the stipulations of the federal “Wild and Scenic River” program. He said the state could end up with a well-engineered bridge “impaling one of the most important wild rivers in the country.”

“We ought to be designing a way to move wood so that we can phase out this bridge as soon as possible, consistent with the original mission to ‘develop the maximum wilderness character’ of the Allagash Wilderness Waterway,” St. Pierre said in an e-mail Thursday afternoon.