How can a lake be defined?

A lake is best defined as a large body of water where currents are primarily influenced by wind. This definition captures the essential characteristics of a lake, distinguishing it from other bodies of water. Lakes typically have relatively still waters compared to rivers, and while they may have some currents due to the wind, they are not predominantly driven by tides or significant currents like a river.

The influence of wind on the surface water can lead to varying water levels and temperature stratification within the lake. This stratification impacts aquatic life and water quality significantly. In addition, lakes often serve as critical ecosystems and can support a diverse range of flora and fauna, depending on their size, depth, and nutrient availability.

In contrast, a small pond with no current does not sufficiently capture the size or characteristics typically associated with a lake. Similarly, a large body of water primarily affected by tides better describes an estuary or coastal environment than a typical lake. Lastly, a reservoir that stores surface runoff refers to a human-made structure designed specifically for water retention, different from the natural formation and ecological function of lakes.