Shallow Pond Freezing, minimum depth for de-icing agitators

[Candlestick3]

We re having an issue where our floating pump platforms being frozen in during the winter on a storm / waste water pond which was designed rather shallow (less than 3m) and wide. They rely on de-icing agitators but the pond depth doesn't seem to be deep enough to support it as some eventually became frozen in place last winter

I was looking for some guidance as to which standards or documents might dictate a minimum depth of a pond to prevent full freezing of a pond with a given surface area and depth and flow rates (being pumped out). the agitator manuals seem to go on the assumption there is simply enough depth of water for them to work

Thanks

 

[miningman]

ambient temperature might be an important part in this dont ya think???

 

[GeoEnvGuy]

What you are describing suggests you want to look at lagoon, aerobic or anaerobic pond design guidelines. These are typically regionally specified in sewage works guidelines. In cold climates the ponds are less effective due to the lack of heat so they don't discharge all year long. The winter months are usually storage with treatment and discharge in the summer months. This makes the ponds large and empty. Aerators are only used to enhance the treatment in the summer months and beached in the winter.

 

[Candlestick3]

Ambient temperature range around -5C to -20C with the coldest days probably around -35C during the winter months.

hmm my operators tell me there is still flow intermittently during the winter so I assume that is during the sunny days trench water flows into the pond and also implying there is still unfrozen water under the ice surface. I couldn't find any calculation type documents relating to the heat retention of the pond so I wonder if it was considered.

Are there any sort of heat barriers that can be placed in the water where I can add some heat in the water and try to retain it in a smaller area like a oil boom but one that will sink into the water a bit and provide a slower heat transfer to surrounding ice