Two North Charleston bridges that are main routes between the Park Circle area and the southern part of the city are scheduled for replacement, with each bridge expected to be closed for a year.

The Spruill Avenue and O'Hear Avenue bridges won't be closed at the same time, but one or the other will be shut down between roughly the fall of this year and the fall of 2016.

Both bridges cross Noisette Creek, just above the former Navy base.

"The bridge closures will be an unfortunate inconvenience for the immediate-area residents for a period of time," said North Charleston spokesman Ryan Johnson. "However, each bridge is in definite need of replacement."

The federally-funded bridge replacement work is expected to be under contract this summer, and the contractor picked for the job will decide which bridge to close first, according to S.C. Department of Transportation spokesman Pete Poore.

The estimated cost to replace both bridges is $11.4 million, he said.

When the O'Hear Avenue bridge is closed, traffic will be detoured over the Spruill Avenue bridge.

"That's going to be a major pain, especially the one on O'Hear, but it is needed," said O'Hear Avenue resident Tony Gentile. "Being in the construction industry, I understand that it takes time to do these things."

When the Spruill Avenue bridge is closed, traffic will be directed to Rivers Avenue.

As a side benefit of the project, the replacement of the two bridges is expected to make Noisette Creek more accessible for recreation.

"We've asked the SCDOT to raise each bridge to allow clearance along the waterway for passive water sports, such as canoeing and kayaking," Johnson said. "Once completed, the new bridges will be a certain improvement to our infrastructure."

There are also bridges that cross Noisette Creek on Noisette Boulevard, leading to the former Navy base, and on South Rhett Avenue.

In recent years North Charleston has been using Greenbelt funding from the special half-percent sales tax to purchase land along Noisette Creek.

The creek meets the Cooper River right next to North Charleston's Riverfront Park on the former base.

Reach David Slade at 937-5552