Pond Boss Forums POND CONSTRUCTION Building a dam Dam Protection?

Here is a picture of my dam when the phone was dry. It has a shelf that is about 2 ft down and 1 wide. I assume that I need to put something there to protect the damn from the waves. I assume rock is the best choice, but I am looking for ideas. What have others done?

Today the water is high enough that it is flowing through the overflow.

Bossone,

Yes, rocks are the best solution. Size and shape will depend upon the size of waves you expect to hit the dam. This depends on the orientation to normal winds, wind speed, and fetch (the distance the wind blows across the water surface).

In a relatively protected area you might be able to get away with field stones that are softball size and smaller. On larger bodies of water you will need much larger stones, and preferably irregularly shaped stone that interlocks together to some point. Otherwise large waves will roll the rocks down into the water over time. Remember that rocks under water have buoyancy, and will move much easier.They use table sized, irregularly shaped quartz stones on the Missouri River impoundments here in the Dakotas.

We have a couple 20 acre ponds that are 1/4 mile long and get 2-3 ft waves, and we use boulders and field stone that range from table size down to softball size.

From the looks of your pond and the location, I'd think you might want to lay some big, anchor rocks at the base of your flat ledge, and then use that size and somewhat smaller rocks above. Make sure you go at least 1 ft above the top of your principal spillway pipe. Another thing you could consider is laying an erosion control fabric down first, and then putting your rock on top. That will help with erosion, and will help keep weeds from growing through the rock.

The other benefit of rock is that it will deter muskrats from burrowing trough the dam.

I notice you have a trash guard on the inlet of your pipe. Make sure you regularly inspect and keep this cleaned off.

Bill

Bill,

Thanks for the info. The pond is protected some and with it being fairly small (1/2 acre)I doubt I have very big waves, but it looks as if it needs something on it. I will see what I can find rock wise and I think the fabric is a good idea to keep the weeds down.

I am amazed just how wet the top of the dam is and in fact on the top (near the pond) from soaking up water from the pond. In fact I got several places where the dirt is wet up to 4 feet away. I assume this is normal and it will stop as some point?