With the Mississippi river up as high as it is, the Meramec river is going to back up as it feeds into the Mississippi. The top left of the map below has a red square where the images were taken. Follow the red line to see the path the Meramec takes to get to the Mississippi river for reference. The red line represents approximately 20 miles of river.
I went out with my kids to explore the flooding first hand. Lucky for us, we were prepared to get wet!
Google Maps
There is a road under this water!
The bridge at Simpson Lake going into the Meramec
Hogan Haake