QUINCY -- The rising Mississippi River is expected to reach moderate flood levels in Quincy by early next week.
The National Weather Service is forecasting the river will reach 23.2 feet in Quincy by Wednesday because of recent heavy rains and snow melt in the upper Mississippi River valley.
Technical flood stage in Quincy is 17 feet. The National Weather Service's river gauge at Quincy was offline this morning. The last available reading on Thursday showed the river at Quincy was 15.6 feet and rising.
The NWS defines "moderate" flooding as 22 to 26 feet. Anything above 26 feet is considered a "major" flood.
The biggest flood in Quincy's history was recorded on July 13, 1993, when the river reached a height of 32.13 feet.
In Hannibal, Mo., the NWS is forecasting the river will crest at 23 feet on Wednesday. As a result of that prediction, John Hark, Marion County's emergency management director, ordered all five of Hannibal's flood walls to be installed starting at 8 a.m. Friday.
"When the river is projected to go to 20 feet, we put in the Hill Street and Center Street gates," Hark said. "If it's forecast to go to 21.5 feet or above, then we put in all five gates."
Since the latest forecast is calling for the river to reach 23 feet, "we stepped up our response to a Level 2, so now all five gates are going in," Hark said.
The closing of the gates means work on Hannibal's $6.6 million riverfront development project will be coming to a temporary halt because the contractor, Bleigh Construction, won't be able to work in a flood-threatened situation.
"I've been in touch with the superintendent of the construction site for the last week," Hark said. "As of Wednesday, they got all the equipment and supplies off the riverfront and back on the city-side of the levee where it's going to be safe from water."
With the flood walls in place, the downtown should be safe from any rising water, but other parts of the city closer to Bear Creek may be susceptible to flooding if the river continues to rise.
For example, Hark said the Admiral Coontz Recreation Center becomes unusable once the river reaches 24 feet.
In Quincy, meanwhile, flooding starts to become a problem once the river reaches around 19 feet, at which time flooding begins to take place at All-America Park, Kesler Park and Bob Bangert Park, according to the NWS.
At 20 feet, Clat Adams Bicentennial Park begins to flood. At 21.9 feet, the lower floor of the Pier restaurant begins to flood. At 22.1 feet, Bonansinga Drive at Bob Bangert Park begins to flood.
The problems become greater once major flooding occurs. At 26.3 feet, the eastbound lanes carrying U.S. 24 traffic across Quincy Memorial Bridge at West Quincy will be closed, and traffic will be diverted to Quincy Bayview Bridge. At 27.8 feet, water starts going over the lock gates at Quincy's Lock and Dam 21. At 28 feet, the city of Quincy starts sandbagging critical areas along the riverfront. At 28.2 feet, damage begins to occur at Quincy's sewage treatment plant.
The National Weather Service has issued flood warnings for all lock and dam locations in this part of the Mississippi River. The agency has reported that the probability for more severe flooding has risen because of recent heavy rains and additional snow in northern Iowa, Minnesota and Wisconsin.
"It is now likely that much of the mainstem Mississippi River will have a high chance of reaching major flood stage levels, with a potential for some locations to reach levels near previous record crests," the NWS's Quad Cities office said in a recent statement.