With all the rain we have received over the last 2 weeks, it has really been evident how much the Forebays we constructed on both sides of the pond have worked to reduce silt accumulation. The walls help to slow the water down, which causes a lot of the larger silt particles to fall to the bottom upstream. By trapping these dirt particles upstream, we can use our excavator to remove the silt and maintain a large area for the water to back up and drop silt. Take a look at the picture of the Forebay after a heavy rain:
This picture clearly shows the different colors of water upstream, and then downstream of the forebay. Upstream is much more "chocolate milk" looking, and down stream much clearer and a lighter shade of brown. This difference in color is because the upstream flow has much more silt, and while the water is forced through the small opening, it effectively helps to settle the silt particles to the bottom before moving through.
Look closely and you will see the Upstream rocks on the right side have a film of silt deposited on them after the water recedes. The Downstream rocks have not silt deposited on them because of the quicker moving, cleaner water. This is encouraging evidence that the Forebay is working just as it was designed to work.
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