Everyone lives within a watershed, unless you live on the top of a mountain or exactly on the edge of a ridge, that is. A watershed creates a sort of forced community, and thus, protecting your watershed and keeping it clean can become as important as caring for you own home!

What exactly is a watershed?

Imagine a watershed as a geographic region where all the water that falls within it arrives to a common point, such as a lake or a river. Watersheds are separated from each other by ridges or other geographic features. When a water drop falls on one side of the ridge, it flows into one watershed, if it falls on the other side, it flows into another watershed.

Watersheds can be delineated on a small scale, such as space between hills, or on a macro-scale, such as the Amazon basin. Another commonly used term for a watershed is a "drainage basin."

If the watershed where you live is in poor health, impurities and contaminates may accumulate as the water flows from the top of the ridges to the output. Additionally, the health of the upland areas of a watershed affects the quality and quantity of the water downstream.

Living in a watershed

On a human scale, what happens within a watershed, whether natural or caused by humans, affects the water quality and health of that watershed, while not greatly impacting neighboring watersheds.

For example, let's say that the "Contaminators" live in watershed A, and the "Envirofriendlies" live in watershed B. Their watersheds are separated by step ridges, but are adjacent to each other.

The Contaminators have been busy logging all the trees in the upper watershed, throwing garbage into the creeks, using chemical fertilizers and pesticides on their gardens, and building lots and lots of paved roads and parking lots everywhere. The Envirofriendlies however, have been busy preserving their forests, keeping garbage out of their water, gardening with organic products on their properties, investing in public transportation, etc.

If we look at the quality of water and the environment within the two watersheds, we'll see a big difference, even though the two watersheds are next to each other.

Watershed A, where the Contaminators live, is quickly eroding because of the lack of vegetation. The water is also highly contaminated because of the trash, pesticides, and fertilizers. Also, because of all the pavement, very little water recharges groundwater resources, and therefore, this watershed is starting to experience severe drought. That's because most of the water leaves the watershed quickly in the form of runoff.

In contrast, watershed B, where the Envirofriendlies live, has more water year round as the water soaks into the ground and is slowly released throughout the year by the capillary action of the trees and plants in the area. Watershed B also has cleaner water, cleaner air, limited erosion, more wildlife, less problems with disease, etc.

Why we should think about watersheds

Watersheds create a sort of forced community of living things. What our common watershed neighbors do affects everyone in the community. Additionally, we have to think of the watershed as a whole connected unit, with the upland conditions affecting the quality of water, air etc. What happens upstream will influence everyone who lives downstream.

Therefore, watersheds are useful to consider when we decide to protect or restore an area. When we get together with our watershed neighbors, we can define the limits of our watershed, look at the environment challenges that we face within our area, and make plans to manage our environment.

Thinking on the scale of a watershed is useful for environmental work as we can scale things down for planning purposes, and therefore have a greater impact on the environment. For example, if we look at a city, we can divide it into watersheds. Then, we can measure the overall health of each watershed and decide which of them need help, and which are in good health. We can prioritize watersheds for restoration that are at risk, and focus on preserving watersheds that are already healthy.

Additionally, it is also easy to monitor the health of watersheds over time, as they are seen as contained units. In the example above, if we measure the water quality of watersheds A and B, we can see the changes over time as the Contaminators continue to chop down trees etc.

Even though the two watersheds are adjacent, the water quality and erosion rates in watershed B will not be affected by the conditions in watershed A. If the Contaminators decide to start some tree planting projects and stop throwing trash in the river, they can monitor their progress by calculating erosion rates and water quality within their own watershed, and the changes conditions in neighboring watersheds will not come into play.

Let's indeed hope that the Contaminators follow the example of our friends in the adjacent watershed!

Now that we've got you thinking like a watershed, below we offer a few resources for you to explore.

Watershed Restoration Resources:

EPA Watershed Page. http://www.epa.gov/owow/watershed/ 

The Watershed Management Council. http://www.watershed.org/wmc/index.php 

EPA Guide to Watershed Monitoring. http://www.epa.gov/watertrain/monitoring/ 

Kent Swanson is a freelance writer specializing in environmental issues. See these websites for more of his work:

EcoBackyard (www.ecobackyard.com)

Practical Environmentalist (www.practicalenvironmentalist.com)

Gardening Gift Guide (www.gardeninggiftguide.com)