The Grand Avenue bridge over the Des Moines River in downtown Des Moines will close for a little more than a year beginning in mid-September for construction of a new $9 million structure that will feature sidewalks that are 14 feet wide on the north and south sides; one lane of parking on the south side; three traffic lanes, one going east and two going west; and a westbound bicycle lane. A specific date to close the bridge has not been established. The bridge will reopen in late 2017. Click here for up-to-date information on the closure and detour maps. Signs will provide a route around the section of the Principal Riverwalk that will be affected by the construction project.