Though work to upgrade the deteriorating Boston University Bridge began earlier this summer, plans for the most significant part of the $2.3 million project have only recently made their way before Boston and Cambridge environmental officials.
Consultants working on behalf of the state Department of Conservation and Recreation recently appeared before the Boston Conservation Commission seeking approval to rehabilitate the 181-year-old steel-truss span, which crosses the Charles River between Boston and Cambridge.
Although the commission conditionally approved the plan, member Stephen Kunian expressed worry that lingering power struggles between the city commission and the state agency could drive the project to court, and potentially set back plans to begin construction on the next phase in the spring.
"I hope we're not going to get any jurisdictional fight. We're not about to give up what we perceive to be our jurisdiction" over the project's environmental issues, Kunian said.
Among the work scheduled for the three-phased project is to repair structural steel, concrete, and granite support blocks, and install an innovative storm-water drainage and filtration system.
The 760-foot-bridge has about eight scuppers to clear storm water from the roadway; their short drain pipes discharge potentially tainted rainwater directly onto the bridge's support structure and then into the river below.
Consultants from Boston-based STV Inc., which is working on behalf of the state DCR, promised that a number of steps will be taken to protect the river and surrounding wetlands from environmental pollutants both during the project and afterwards. Among the measures are new drainage lines to direct storm water away from the bridge, and new water-filtration systems that would be built on both the Boston and Cambridge ends of the bridge and treat 70 to 75 percent of the roadway's runoff to remove oils, chemicals, and other contaminants before sending it into the river, they said.
Rainwater runoff from paved surfaces is "the number-one source of pollution to the Charles," said Robert Zimmerman, executive director of the Charles River Watershed Association. Although he hasn't seen the specific plans for the BU Bridge yet, Zimmerman said, he called the perhaps 75 percent capture rate "great" and said he's "not surprised" at how extensive the measures will be, given the talks that his group and the DCR have had over the issue of storm-water management in the last several years.
"They're doing a terrific job. They've seriously stepped up to the plate," Zimmerman said.
"The proposed design collects bridge runoff and removes sediments via hydrodynamic separators before it enters the river. The hydrodynamic separators will remove 90 percent of the suspended solids during a 10-year storm event," DCR spokeswoman Wendy Fox stated in an e-mail discussing the treatment plants.
She added that smaller storm grates will be installed to filter out "greater levels" of trash from the runoff than the grates now in use.
The consultants assured commission member Vivien Li and others that the work to repair the bridge's stone pillars and the sandblasting of faded lead paint would be fully contained by a plastic canopy, so that construction equipment and the debris and dust generated by the work would not contaminate the surrounding area. Any lead-paint dust created would be taken to a hazardous-waste disposal site, they said.
The Cambridge Conservation Commission, which also must approve the plan, had just received the proposal last week and had not reviewed the plan in depth, said commission administrator Jennifer Wright. The panel intends to take up the matter at a public hearing on Sept. 8, from 7 to 9 p.m. in the City Hall Annex, 344 Broadway.
If approved, the project would feature the first storm-water filtration system on any bridge in Cambridge, said Wright.
In noting the possibility of disagreements with the Department of Conservation and Recreation, Kunian said he was "disturbed" that some sidewalk upgrades to the bridge had already begun before the state agency had secured the Boston commission's go-ahead for the bulk of the project.
He noted DCR's recent track record for acting without consulting the commission on issues that affect the Charles River and abutting wetlands. He cited what he said was the agency's costly mishandling of a gift of 100 cherry trees, planted without approval in the lagoon area along the Esplanade in 2004, that eventually had to be moved and replanted due to widespread public outcry.
"That was embarrassing and cost the DCR money," he said.
According to Fox, bidding on the BU Bridge project is expected to occur in late October, with construction starting in the spring.
"At this juncture, the designers do not have final cost estimates, as aspects of various elements of the design are currently being refined," she said. "The construction period is anticipated to extend from 30 to 36 months."