Sediment Forebay - Wentzville, MO
Posted by: 
YoSam.
N 38° 49.024 W 090° 52.315
15S E 684756 N 4298628
One of two markers at the east end of the lake.
Waymark Code: WM1C3ER
Location: Missouri, United States
Date Posted: 05/27/2025
Views: 0
County of marker: St. Charles County
Location of marker: William Dierberg Dr., Heartland Park, Wentzville
Marker Text:
SEDIMENT FOREBAY
TRAPPING SEDIMENT AND POLLUTION
What is a sediment forebay?
Imagine you left your house on vacation and then came back a few weeks later to a thicker than normal layer of dust over all your furniture. Pretty annoying, right? The dust was able to collect because there was very little air movement in the house while you were away, allowing the dust to settle.
Unlike dust and furniture, when it comes to water quality, we want particles to settle. As stormwater flows along the surface of the earth, it collets dirt, debris, and other pollutants; which often times end up in lakes, just like the one you see here at Heartland Park. A sediment forebay stops sediment and pollution from entering the lake by allowing it to settle, keeping the water in the lake clean.
As you can see before you, a forebay is a small basin located where water enters the lake. A dike made from large rocks separates the forebay from the lake. This barrier slows down the water , causing it to temporarily pool. By slowing and holding the incoming water, forebays give time for sediment and heavy pollutants to settle to the bottom before the water enters the lake.
Clean water means occasionally getting dirty.
Just as you need to dust your furniture after you return from vacation, the sediment that accumulates in the forebay needs occasional removal. So every few years, the layers of sediment are cleaned from the forebay floor. It may be a dirty job, but without the forebay, sediments would pour into the lake and accumulate on the lake bed.
Over time, the lake would fill up with so much sediment that the water would be to shallow to keep fish alive. Shallow water depletes the oxygen levels, which can lead to fish kills. During the winter months, ice build-up in the shallow water can also kill fish and further reduce the oxygen levels in the water.