The stress of wind moving over the lake surface causes a transport of water within the lake, as well as the movement of energy downwind through the mechanism of surface waves. The wind is therefore one of the most important external forces on a lake.

Movement in a lake occurs through both physical and biological processes, creating a dynamic system rather than a stagnant pool. Physically, the water itself moves via currents, waves, and internal seiches (oscillations) driven by wind and temperature gradients. One of the most critical physical movements is lake turnover, where water at the surface and bottom switch places seasonally as temperatures change, which redistributes oxygen and nutrients throughout the water column. Biologically, the lake is a hub of constant motion: zooplankton and phytoplankton migrate vertically through the water daily based on light levels, while fish, insects, and larger organisms move horizontally in search of food or breeding grounds. Even the lakebed is in motion, as sediment continuously settles or is stirred up by bottom-dwelling creatures. From the microscopic "streaming" within single cells to the massive, wind-driven surface ripples, every layer of a lake is characterized by constant energy transfer and displacement.