What causes mud from the bottom of a body of water come up to the surface when it’s near a flowing culvert?


As seen at 58:45 in this video: [https://youtu.be/CTgbVjJnR1E?t=3525](https://youtu.be/CTgbVjJnR1E?t=3525)

In: 7

Decomposing vegetation on the bottom creates gasses. These gasses can be dissolved in the water/muck on the bottom to the point of saturation. When the water level drops slightly or muck is removed, the pressure drops and the gasses can come out of solution creating bubbles. These bubbles rise to the surface, drawing fine solids along with them.

My guess is the slight water level drop caused by the culvert flowing allowed these gasses to start bubbling out of the bottom muck.