Fluctuating water levels are dependent upon the amount of water going in and out of a body of water. Water levels rise when there is more precipitation and cooler and cloudier conditions that cause less evaporation. Less precipitation and warmer temperatures result in lower water levels.
Water level fluctuations may be short-term, long-term or seasonal. Short-term fluctuations may be caused by changes in barometric pressure or storms. These changes may last from a few hours to a few days. Long-term fluctuations, on the other hand, require years of changes to precipitation and temperature conditions to make water levels rise and fall.
Seasonal water fluctuations correspond to the changing of the seasons. Warm seasons, such as the spring and summer, result in more water coming in and less evaporating. The opposite is true for colder seasons when water levels decline.