Why shouldn’t an opening be placed at or near the bottom of a sediment pond?
An opening placed at the bottom of a sediment pond such as in a principal spillway riser pipe would eventually force the pond to empty, along with most of the fine sediment particles concentrated near the bottom of the pond, during and after the storm. The purpose of having a permanent pool of water is to allow sediment particles to settle out and remain in the pond while skimming off or dewatering the upper layer of relatively clear water near the pond surface. A riser with a bottom opening, surrounded by rock, is not effective in removing fine sediment particles.
