A revised intergovernmental agreement that increases by $112,155 the design cost of a proposed bridge over the Chattahoochee River has been approved by the city councils of Roswell and Sandy Springs.

The two cities will split the cost, each contributing $56,077.50, according to staff reports. The fee modification was requested by engineering consultant Health & Lineback, due to additional environmental and design documents required for the pedestrian and bicycle bridge at Roswell Road (Ga. 9) and the river.

The Georgia Department of Transportation turned down a request to cover half of the additional cost, Roswell staff said. As a result, Roswell and Sandy Springs will have to contribute a total of $156,077.50 each toward design fees, up from $100,000 previously. Federal funding of $400,000 covers the balance of the $712,155 total engineering cost.

The latest changes “will get the project to construction,” Roswell staff said. Construction costs are estimated at $3.22 million, of which $2.58 million will be federally funded.