Pond Boss Forums POND CONSTRUCTION Soil questions Leftover topsoil any use for pond?

Some clays will tend to stay in suspension and cause muddy looking water.

My NRCS guy said that our type of clay likely would and If I wanted a clear water pond to line the pond with a couple inches of topsoil. Silt particles are much larger (eidt: I originally said smaller - wrong - clay particles are much smaller than silt, that is why the clay stays suspended) than clay, and will precipitate out of the water column much better. We have an old pond that tended to stay muddy looking so I took his advice.

Now the good and the bad of lining a clay pond with topsoil. The good is we have never had muddy looking water. The top soil did the job of not having clay particles suspended in the water. The bad is that our topsoil had a lot of nutrients in it. That can be a good thing if your watershed does not give off much nutrient load. It can keep you from having to fertilize to get a plantonic algae bloom. In my case the topsoil was pretty high in nutrients and we do have some nutrient load from runoff from agricultural land. So we have had some problems with FA because of the abundant nutrients.

So lining a clay pond with topsoil can have some good results in keeping the water more clear (if the type of clay you have tends to stay suspended in water - not all do). It can also have some disadvantages. Plus you are already filling some of your water capacity with dirt. So the answer is "it depends".

If your BOW will take a long time to fill, another thing topsoil lining the pond would do is let you establish some grass in the bowl of the pond. This has some specific advantages like erosion control during large rain events and also provides some good places for new fish fry to hide and eat till some water plants get established. I did this on part of the pond and I think it helped the pond life cycle get established during fill.

So I'm giving you some pro's and con's of lining the pond with top soil. It does not take much to cover the clay. The less the better actually but still covering the clay.

The other thing I would consider doing with if the top soil pile would be in the way or an eyesore is to just slope the back side of the dam even more with it. Gentle slopes are so much easier to keep mowed and maintained, so if the dirt is excess and you think you will never need it elseswhere, that is a good place to waste it.