Pond Boss Forums POND CONSTRUCTION Building a dam How deep is too deep?

Pond Depth. I will expand on Bob's "fish production mostly occurs in the top 4' of water. Fish production in a pond or lake is dependant on the light penetration depth. Fish production down to 4' is very true if the water is fertile or fertilized and light visibility is approx 18" to 2'. But if the water is not very fertile & the water is clear then the general rule will be: fish production zone will be down to the lower limit of rooted weed growth; sometimes 8' to 16' deep; but usu. 6'-10' is the most common range for clearish lakes. This depth of (fish) production is called the LITTORAL ZONE.

Pond Depth & Mixing. Many people "up North" including most pond builders think it takes a "deep pond" to make the water mix or circulate. They think the deeper the pond is the better it circulates. No way! Pond water does not turn or mix deep (8-20') into the depths during summer. It also does not mix very deep under the ice in winter. A pond designer once told me "ponds don't turn in summer; there's no crank on them". He was mostly correct.

Ponds do turn, or roll, or mix top to bottom twice a year. Once in the spring and once in the fall. This primarily occurs when the water is around 39-40 deg F. Or, when surface water temp is close to bottom temp. When the water is uniform temp. top to bottom there is very little resistance to mixing and wind can push & pile water on the downwind bank and it is then forced downward along the bottom. If the water is cooler along the bottom the water will push down until it meets the thermal cold resistance and then push laterally or horizontally along the top of the cold water.
The degree of temperature difference between the surface and bottom waters and the wave height determines how deep the pond water will mix.