How big is a watershed?
pop-up #21
How big is a watershed?
Watersheds come in different sizes. The size of a watershed can vary depending on the point of discharge chosen to define it. If the chosen point was the mouth of a major river that drains to the ocean, the watershed would likely be very large. However, if you chose a point upriver at the confluence of two streams, the watershed would be much smaller.
For example, Albuquerque sits in the Middle Rio Grande Watershed, which itself is part of the larger Rio Grande river basin. Within the Middle Rio Grande Watershed are smaller ones – often referred to as “subwatersheds” - such as mountain canyons that drain to a stream or arroyo.
You can define a subwatershed as small as the drainage area for a housing development, or even a road culvert. In fact, engineers often do this to design things like storm drainage facilities.
