Pond Boss Forums POND CONSTRUCTION Building a dam "Flash Board" For Level Control?

Recently I ran into this design for controling pond level that just uses boards. So called a flash board feature. Why it has that name I know not. But my question is; has anyone ever used one and how do you think it would hold up in an ice condition? The pond I want to put in is in Michigan and we can get some really solid ice.

I should explain that alyhough my pond is being designed for a 20' depth, it is mosty dug out and my dam will only be about 2 - 3 foot above the discharge.

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Called flash board risers they are used mostly in shallow water situations (flooding and impounding fields for duck hunting or rice production)to regulate water depth. I have never seen one used on a pond with a dam and more than 3-4 ft of water. I would not consider using one on a normal pond design especially with ice (better options). Strength is not there strong point and with large vols of water pressure builds up against the boards.

Just to offer some food for thought:

Where I go grouse hunting in WI, I run by these risers installed by the state all over the place in the flooded marshes/canals that they use to control the water and drain it as well. Most are only 3-4 feet deep however several are 8-15 feet deep and all seem to be functioning fine. And I know they get some ice up there. I have thought of installing one in my own pond (when it gets built) but from what I have seen, is that they leak between the boards which makes me wonder on the effectiveness of the device.

TMK, The depth of the pond below the discharge pipe has no relevance, because the pressures will be lateral. The only pressure that will be applied to the flashboards are relatively low and come from the blocked water only. These pressures will rise as the level of blocked-off water rises. It is fairly simple to create a flashboard riser system but to seal it is much more difficult, but can be done. On a discharge pipe (vertical Riser) that is surrounded by ice, failure will probably occur, however, if the discharge pipe is lateral the ice expansion pressure is far less.

There is a state owned 70 acre lake in my area that is 20 feet deep max. They have a flashboard riser for the primary spillway and have 2 x 12's for the boards. The lake has been there for 80 years. The water level at the riser is approx 4 foot and last year there was 26 inches of ice on the lake. I was talking to the Conservation officer and he said they used waterproof caulking between the boards to prevent leaks. It flows large quantities of water over it with no problem.