A watershed is an area of land where water drains from higher parts to the low points. The high elevation areas in a watershed form the edges or boundaries of a watershed, moving water towards the low points in the valleys or rivers where water collects and flows. If we are on land, we are always in a watershed.
Watersheds are similar to sinks in a kitchen but are much bigger in size since they are defined by the shape of the land surrounded by hills or mountains. A sink is a small example of a watershed where water flowing on the edges of a kitchen sink runs down towards the drain at the bottom. On a larger scale such as a landscape, water moving downhill in small areas will lead to arroyos that only flow occasionally and will lead down to rivers or streams that are flowing all year. The water flowing will eventually end up in a larger waterbody like a lake, reservoir, large river, or eventually the ocean.
As the water flows, it often picks up pollutants caused by people which may have negative effects on the health of animals, plants, communities and farms. For example, during periods of heavy rain and snowfall, water may run off of hard surfaces that are impervious to water soaking into the ground such as parking lots, roads, buildings, and other structures. Because water has no way to soak into the ground, it flows quickly off the hard surface. These impervious surfaces act as “fast lanes” that rush water directly into storm drains and rivers. The high water speed and volume can quickly overwhelm streams and rivers, causing them to overflow, erode soil, and possibly result in floods.
When we learn about the negative impacts on water such as creating pollution or causing flooding from impervious surfaces, we can change how we use the land, reduce or eliminate sources of pollution, and use water more wisely. This will improve conditions in the watershed to better water quality and quantity all around. Because water is life, we need to protect and care for our watersheds wisely so that we can have water security for everyone and ecosystems around us.