Stillwater

Stillwater refers to water that is not moving relative to its surroundings, in contrast to flowing rivers or streams. It occurs in lakes, ponds, reservoirs, and other bodies where currents are weak or dampened by depth, wind shelter, or human-made controls. The term can also describe a momentary state of calm in a larger body of water.

Ecologically, stillwater conditions influence oxygen distribution, temperature stratification, and nutrient cycling. Deeper still waters may become oxygen-depleted at night or in summer, promoting stratified layers and the growth of certain algae and aquatic plants. Stillwater habitats support species adapted to calm conditions, such as some fish, amphibians, waterfowl, and invertebrates, but can also harbor mosquitoes in stagnant patches.

From a human perspective, still water shapes uses and management. It is common for recreational lakes and ponds to be maintained as still waters for boating, fishing, and aesthetic purposes. In drinking-water supply, stagnation can affect taste and odor and is often mitigated by circulation, aeration, or treatment. In agriculture and aquaculture, stillwater systems are designed to maintain calm conditions for stock and crop irrigation.

Place names: The term is used in geographic toponyms in various countries. In the United States, notable places include Stillwater, Minnesota, a city on the Saint Croix River, and Stillwater, Oklahoma, home to Oklahoma State University. There is also Stillwater Township in New Jersey. These names reflect historical associations with calm or unmoving water in the local landscape.