Navy Pier is Chicago’s top tourist draw, and local officials were set make it even more attractive by building a giant marina on the pier’s north side for boats to come and go throughout the day.

It was estimated the addition could bring $10 million in annual economic revenue to the city. So why has the project, which received the green light from Chicago City Council, the state’s Department of Natural Resources and the Army Corps of Engineers, suddenly run into choppy water?

The tiny sliver of Lake Michigan between Navy Pier and the Jardine Water Filtration Plant is free and clear for all boaters to use.

In 2016, Navy Pier officials asked City Council to approve an update to the pier’s planned development, authorizing, among other things, the construction of a transient marina on its north side, where boats could dock for the day. It was unanimously approved.

Chicago developer Randy Podolsky landed the contract to build and operate the marina because he says boaters like himself had been clamoring for it.

“A marina that would allow boaters from Chicago or from around Lake Michigan, all around the Great Lakes, to stop at Navy Pier and enjoy all the city has to offer,” Podolsky told WTTW News.

The plans call for 6,500 feet of broadside mooring along the pier, with slips for between 130 to 150 boats — both big and small.

Podolsky proceeded to get the necessary permits. The Army Corps of Engineers and the Illinois Department of Natural Resources all signed off. But one big agency held out — the city of Chicago’s Department of Transportation.

“The quoted response by CDOT: unspecified security concerns,” Podolsky said.

Those concerns relate to the relatively unguarded south side of the Jardine Water Purification plant, which treats water for two-thirds of the city of Chicago and many surrounding suburbs. Since the project’s approval, water department officials have expressed concern that allowing hundreds of boats to dock mere feet from the plant could pose a grave security threat to Chicago’s drinking water.

Podolsky did not believe the concerns were warranted.

“Cybersecurity is the biggest threat that the water department faces,” Podolsky said, as opposed to a boat hypothetically docking and someone jumping off to enter the facility.

Podolsky says that if the department was truly concerned about security, then perhaps it would do something about the hundreds of boats that routinely dock and hang out in the area off the north side of the building near Oak Street Beach — colloquially known as the playpen. Podolsky says his operation would entail strong security checks.

“Boats would have to register with us,” he said. “We would know boat registration, driver’s license numbers, credit cards, basically everything there is to know about the driver.”

Podolsky has now sued the city to force them to issue his construction permits. He says he believes certain city agencies have gone rogue.

“Who the heck is CDOT to not issue a permit for something City Council approved unanimously?” he said.

Navy Pier, the Chicago Department of Water Management and the Chicago Department of Transportation all declined comment, citing the pending litigation against the city.