Missouri River High, But Not Alarming

Despite this weekend's rainfall, city staff said there's no cause for alarm as they watch Missouri River water levels.

With water levels expected to rise, officials from the City of Chesterfield and the Monarch-Chesterfield Levee District continue to monitor upstream Missouri River conditions. Chesterfield Planning and Public Works Director Mike Geisel said there's still no cause for alarm in a recent email through the city's email river update service. 

There is some significant flooding on the upper Missouri River, and the U.S. Army Corps of Engineers has begun a controlled release of some of the water from the Gavins Point Dam, which is on the border of Nebraska and South Dakota. Last week, the discharge from the dam was increased to 160,000 cubic feet per second, up from a normal output of about 130,000 cubic feet per second. Chesterfield Public Works Director Mike Geisel said in an email that the extra discharge isn't a significant amount.

"The entire discharge from Gavin's Point represents less than half of the Missouri River flow at (the current) stage in St. Charles," Geisel said. 

The St. Charles gauge, which is about one-half day downstream from Chesterfield Valley, was at 24.26 feet Monday morning, Geisel said. It's expected to rise through Saturday to about 30 feet.

The Hermann, MO gauge, which is about one day upstream from Chesterfield, read 21.51 feet Monday morning, with a predicted crest occurring Friday of 28.6 feet. However, Geisel said there's no cause for concern. 

He offered up information about the Great Flood of 1993 to put concerns in perspective. That flood, he said, exceeded 40 feet at the St. Charles gauge. And the Monarch-Chesterfield Levee has been raised anywhere from 5 to 8 feet since then, depending on location. Sand berms have been added and the levee has been widened. It's believed that the levee would protect the Valley even if water levels rose to 47 or 48 feet at the St. Charles gauge.

The agricultural levee might eventually be topped this summer as high river levels continue. That levee, which is about 2,000 feet north of the Monarch-Chesterfield Levee, has not been overtopped since 1995. Geisel said that was a ten-year levee; under normal conditions it's expected to be overtopped every ten years on average. If the St. Charles gauge reads between 33 and 34 feet, the agricultural levee will likely be overtopped. But that's not a cause for concern, Geisel said.

"While the agricultural levee performs an important function in keeping sustained water off of the main levee, overtopping is not a critical issue not does it warrant emergency action," Gesiel wrote in the email. 

Geisel said the city will continue to monitor river levels and update residents as needed. If necessary, the city will initiate the , but at this point no watch, warnings or advisories are called for.