Thermal Stratification of Ponds
One of the principal reasons for pond aeration systems is due to the thermal stratification that can take
place. This occurs as the warmer water rises toward the surface forming a warm water layer with the
cold water at the bottom.
Thermal stratification becomes particularly troublesome in the summer months for ponds that are 8 to 10 feet or
greater, as the warmer water rises to the surface and the denser cold water sinks toward the bottom of the
pond. The difference in density due to the temperature creates these thermal layers that inhibit any mixing
between the layers. Thus the lower cold layer of stagnant water, unable to bring in dissolved oxygen through
the wind or diffusion, becomes less and less oxygenated.
Thermal stratification causes a depletion of oxygen and algae growth.
3 degrees or more between top and benthic