Information about Levees
Levees are not all the same. Levees are classified as either urban or agricultural levees because of different requirements for each.
1. Urban levees are built very high to protect cities and towns against floods of great magnitude. Levees that reduce flooding in communities, providing protection for communities; industrial, commercial and residential facilities. Most major levees protecting urban areas have been built to U.S. Army Corps of Engineers (USACE) standards. Two levees in St. Peters, the Old Town Levee and the Lakeside 370 Levee, are levees that have been built to current U.S. Army Corps of Engineers standards.
2. Agricultural levees are smaller levees that provide relatively lower levels of protection from flooding in lands used for agricultural purposes. These are generally 50-year or 25-year levees, designed to protect against lesser flooding events. For example, these kinds of levees are generally found along the Dardenne and Sanfort Creeks.
Many of the levees you are hearing about in the media coverage of the current flooding situation are agricultural levees. When these levees are overtopped, this means that the water is going over them because they weren’t built to protect against higher flooding levels. When a levee is overtopped, that does not mean that they are "failing." They simply weren’t built to stop the kind of water they are facing. They have not been built to current U.S. Army Corps of Engineers standards.
What Kinds of Levees Protect St. Peters?
The Old Town Levee
is a certified federal urban levee built to current U.S. Army Corps of Engineers standards to withstand a 100-year flood event, or a one percent chance of a flood of this magnitude.
The Old Town levee protects St. Peters’ Old Town, the City’s water treatment and wastewater treatment facilities, Recycle City, Earth Centre, agricultural land, and several light industry and retail areas from floodwater coming from Spencer Creek, Dardenne Creek and the Mississippi River.
The Lakeside 370 Levee
, which protects Premier 370 Business Park, is a non-federal, privately built, certified urban levee built to current U.S. Army Corps of Engineers standards to withstand a 500-year flood event, or a 0.20 percent chance per year for a flood of that size. The "Flood of 1993" was a 250-260 year flood event.
The Lakeside 370 Levee is three and a half miles from the Mississippi River. The levee protects Premier 370 Business Park. It does not impact communities upstream, downstream, or across the river in Illinois. The levee has received permits from the U.S. Army Corps of Engineers and the Missouri Department of Natural Resources and will not raise flood levels during a 100-year flood event. During a 500-year flood event, the levee would have .02 of a foot impact, or less than a tenth of an inch, on water levels.
Both of these levees meet or exceed current federal standards and are monitored and maintained to U.S. Army Corps of Engineers standards.