Local and state officials say the discovery of mussels living in the Cuyahoga River can clearly be seen as a positive indicator of water quality improvements in the Crooked River.

If and how the invertebrates may affect construction of the new bridge from Fred Fuller Park to the Kramer Ball Fields is a bit murkier.

Brian Peck, an environmental specialist in the Ohio Department of Transportation's District 4 Office, said the mussels' presence "absolutely" is a good sign of improved water quality in the river.

"They’re a pretty sensitive species," Peck said. "There’s a lot of rivers and streams that do not have the mussel species in them they once had."

A surveyor for ODOT inspected the area of the river where the old bridge will be demolished and a new one built in its place on Aug. 20 as part of a broader environmental impact study related to the project.

The surveyor found three mussel beds — river habitat with multiple live mussels — and the presence of three species of mussels.

Among the mussel species found was the Eastern pondmussel, which is listed on the Ohio Endangered Species List. The other two species found were the Fatmucket and Giant Floater mussels, both of which are common freshwater mussel species.

Peck said regardless of the presence of the endangered mussel in the river all the mussels must be relocated, per federal requirements, before construction on the new bridge can start.

"One living (Eastern pondmussel) was found 50 feet upstream of the bridge, and they also identified suitable habitat along the edges of the river … that were suitable for that species," he said.

Peck said mussel beds are characterized by gravel substrate in the river bed with the right water depth and flow.

"If you find one mussel here and one mussel there, that’s not a mussel bed," he said. "You have to have a lot of individuals."

A thunderstorm on the day of the survey muddied the waters and made it somewhat difficult to identify all the mussels, so there may be more present — even of the Eastern pondmussel. The survey was conducted as a presence-absence survey, Peck said.

"So they didn’t look and identify every single mussel they saw out there," he said. "They got a representation of what they saw out there."

One mussel bed was found upstream of the bridge and lies within the construction limits of the project, according to ODOT's environmental report on the project. The second and third mussel beds are downstream of the bridge but may be affected by siltation and other side affects of the construction process.

City officials are optimistic that the presence of the mussels won't create a big delay in replacing the bridge, which provides the only access point to the Kramer Ball Fields.

Rhonda Boyd, senior engineer for the city of Kent, said the city is already working with consultants and trying to contract a malacologist — a biologist who specializes in mollusks — to relocate the mussels.

"I wouldn’t say necessarily that it’s going to affect the timeline much," she said. "It’s just that we need to make sure the timeline of relocating the mussels is done within the window we have before we start construction. And we’re doing everything we can to push the bridge along and be sensitive to the environmental (conditions) we have found."

The mussels must be relocated six months prior to start of construction.

Federal money for the estimated $1.16 million won't be available to the city until July 2013, and that means the city may be on the hook for the cost of moving the mussels if it happens before the grant money is available.

The relocation of the mussels will likely take place while the city is bidding the project and trying to identify a contractor for the work.

But the city plans to try and use some of the grant money to pay for the mussel relocation, Boyd said.

"We're trying to shorten down review times and keep on top of people involved with reports on the project so we can make sure we keep the project moving and it doesn’t sit somewhere on somebody’s desk for a couple of weeks longer than it needs to," Boyd said.

Construction is expected to start in late fall of 2013 with the new bridge open possibly in spring or early summer of 2014.

The added presence of the mussels may create more work related to the project, Boyd said overall city officials see their presence as a positive sign of the river's improvement.

"Most definitely," she said. “It’s good to know they’re there."