What term describes particles suspended by the natural action of flowing water?

The term that describes particles suspended by the natural action of flowing water is "suspended solids." These are tiny particles, such as silt, clay, and organic matter, that remain afloat in a liquid due to the movement of water. In flowing water bodies, the continuous motion helps keep these particles suspended, preventing them from settling to the bottom.

Suspended solids are significant in various water quality considerations, as they can affect water clarity, reduce light penetration, and cause harm to aquatic life if present in excessive quantities. Managing suspended solids is crucial in drinking water treatment processes to ensure water is clean and safe for consumption.

The other terms listed refer to different states or forms of solids in water. Settleable solids are those that can settle out of water under quiescent conditions, sludge is a combination of settled solids at the bottom of a water treatment tank, and dissolved solids refer to contaminants that are fully soluble in water and cannot be filtered out using standard filtration methods. Understanding these distinctions is important for water treatment and environmental science.