A Mississippi River flood crest of nearly 29 feet is expected to arrive in Hannibal Friday afternoon, May 3.
The projected crest of 28.8 feet would rank third on the community's list of historic crests. Only the record flood crest of 31.8, seen on July 15, 1993, and a crest of 29.54 feet, which occurred on June 18, 2008, would rank above Friday afternoon's crest.
"It's bigger than I want," said John Hark, emergency management director for Hannibal and Marion County, regarding the anticipated crest.
With additional heavy rainfall still in the forecast for the Hannibal area and to the north, Hark said the crest could be pushed higher yet.
"Anything is possible," he said. "This thing has gone up a half-foot or foot about every 12 hours. We started out at 20.3 feet, that's what we were down to."
The height of the city's flood gates and levee will be raised as a precaution. As of Wednesday afternoon, Hark was waiting to hear back from the U.S. Army Corps of Engineers regarding how best to accomplish that task. Hark was hopeful that work on the levee could begin Wednesday afternoon, or at the latest, Thursday morning.
Hark said that both the city of Hannibal and Marion County issued state of emergency declarations Wednesday morning. Ralls County was expected to do the same Wednesday afternoon, Hark said.
Hannibal has already seen three river crests this spring. On March 26, the river peaked at 23.65 feet. The highest crest thus far in 2019 occurred on March 31 when the Mississippi rose to 25.81 feet, which ranks seventh all time. The latest crest occurred April 11 when it went to 23.52 feet.
All five of the city's floodgates were installed on March 15.
Heath Hall, general manager of the Hannibal Board of Public Works (HBPW), said the rising water has not created any unexpected problems yet.
"With the river expected to continue to rise, there will be some issues with the sanitary sewer system. As the underground piping system gets inundated with groundwater, we expect some basement backups and overflows to possibly occur," he said. "The Wastewater Treatment Plant continues to have higher than normal flows."
The HBPW has been operating in accordance with its flood prevention protocols since the Mississippi reached 20 feet for the first time weeks ago. When the river reached 24 feet Wednesday morning HBPW personnel began making daily visual inspections of the pumphouse, located on Bridge Street, and the Wilson Street lift station, a sanitary sewer lift station located near Ely Street.
"Both locations have concrete floodwalls, but the gates have to be closed and sealed," Hall said. "Also sump pumps had to be installed on float systems inside the floodwalls to pump out any leakage of rainwater. These preventative measures have been in place for a few weeks now and will continue to be monitored both remotely with electronic alarms and at least once per day with a visual inspection."
Hall said the precautions are warranted since the forecast crest will approach levels not seen since 1993.
"We are preparing for the worst. Hopefully reality is better," he said.