How to Build a Lined Silt Pond
Silt ponds are small ponds that catch water before overflowing into a larger feature pond. The purpose is for runoff and silt to accumulate in the bottom of the silt pond before getting into the feature pond. In my case, I am using a silt pond, because it is much easier to clean out than my feature pond. This way, when the silt pond gets full, I can easily drain the two foot deep pond and shovel out the silt into my tractor bucket.
1. Your silt pond should be situated above your feature pond in position to catch as much silt as possible.
2. Dig the hole. I dug a 16’ x 10’ hole that ended up being 2 feet deep. The size of a silt pond really depends on how much silt you get and how often you want to clean it out. I couldn’t find any literature on sizing for a silt pond.
3. Build up your walls if on a slope to level the pond. It is important to compact every 6 inches of fill as you are building up.
4. Set your inlet and spillway heights. I used a laser level to get this right. Make sure you have enough freeboard (height on your walls above water level) to accommodate a large rain storm without having your silt pond overflow.
5. Add the underlayment. This will stop any rocks from puncturing your liner from underneath.
6. Add your liner, and hold in place with rocks.
7. Dress up the edge, so it is more attractive. I folded the liner in and used stone to cover. I think this could be done much nicer if the edge of your pond is not so steep. Then the liner could be covered with stone or even gravel.
8. Unless you have regular water coming into your silt pond, it may become pretty stagnant. It might be a good idea to run an aerator in the bottom.