Estimating Stratification in Shallow Water Bodies from Mean Meteorological Conditions

The level of stratification within ponds, lakes, and other wetlands is a strong determinant of water quality. It is shown here how the stratification in shallow systems (to a few meters deep) can be described in terms of two nondimensional parameters, which are functions only of the water depth, turbidity, mean wind speed, and mean solar radiation. The functional forms have been derived from flows generated by a coupled atmospheric boundary-layer-water-body model. The results generally provide very satisfactory estimates of the stratification in a shallow lake in southeastern Australia and are also shown to be consistent with an existing criterion for the initial onset of stratification in shallow systems. It is suggested that with further validation, the simple empirical description of stratification conditions provided here might be usefully incorporated into existing wetland management strategies.