HAMILTON TOWNSHIP — The Cotton Mill Bridge over the Great Egg Harbor River will close this spring for the next two years.

The current bridge, built in 1940, will be replaced by a new one that will be a little more than 100 feet long in the same location in downtown Mays Landing, near where Main and Mill streets meet at Lake Lenape. It will cost more than $6.44 million and will be paid for by the state and Atlantic County, officials said.

The county will pay $2.8 million through bonds, and the balance will be paid by the state Department of Transportation, said Douglas E. DiMeo, Atlantic County’s supervising engineer for bridges.

The state inspects all major bridges every two years, said Mark V. Shourds, the Atlantic County engineer.

A steel plate is covering a hole on the Cotton Mill Bridge, but the hole in the deck does not mean the bridge is in danger of collapsing, Shourds said.

“Basically, bridges were designed for 50 years. Nowadays, they are designed for 75 years,” DiMeo said.

County officials knew there were problems with the bridge, having declared it functionally obsolete years ago, but it takes years to design a new bridge and go through the permitting process for construction, Shourds said.

Plans for the bridge needed to be approved by the state Pinelands Commission, the state Department of Environmental Protection, the U.S. Army Corps of Engineers, the U.S. Coast Guard and the National Park Service, said John E. Peterson, Atlantic County’s planning director.

Bids were awarded late last month, including to R.E. Pierson Construction Co. of Pilesgrove Township, Salem County. Contracts are being written. A pre-construction meeting still needs to be held, Shourds said.

Additionally, there are in-water work restrictions from April 1 through June 30 in the area because of fish spawning.

Utilities — sewer, water and gas — will be maintained during construction. A temporary utility bridge will be built parallel to the existing bridge, and some large cranes will be on the bridge during portions of the project, Shourds said.

“We want to get the temporary utility bridge in before April 1,” said DiMeo, who added three months of utility work probably needs to be done before the bridge can be started.

The plan is to demolish the current bridge right after July 1, Shourds said.

Peterson expects the project to affect traffic in downtown Mays Landing. A significant amount of traffic use the bridge both during the summer and in the offseason. Alternate routes will be set up during construction, he said.

If the bridge is not replaced, it will have to close eventually, said Peterson, who added repairing the bridge was considered but that was not found to be cost-effective.

The county is responsible for maintaining and repairing bridges within its borders with the exception of state bridges and turnpikes. There are 55 major bridges in the county that are more than 50 feet long and 145 minor bridges between 5 and 20 feet long, DiMeo said.

“At least two other bridges will go to construction in the county during this project,” DiMeo said.