Most people visualize a headwater as a powerful gush of water over a falls or a single bubbling brook high in the mountains at the source of a stream. But in fact, rivers have no single source. A network of springs, creeks, streams, and tributaries drain into the upper portion of a river’s system to form its headwaters. These network waterways are often found in the mountains but may also include desert springs and seeps, wet meadows, or even bayou-like channels. The headwaters of a reservoir are the waters at the far upstream end, where the river empties into the lake. Headwater streams are critically important to the whole river system, providing habitat to the flora and fauna of their own ecosystems and delivering nutrients and organic material to downstream regions. Headwaters can also carry pollution and damage downstream. For example, the Mississippi River begins in Minnesota, carrying agricultural runoff pesticides and farm chemicals all the way to its mouth in New

Mary Swander