What's Your Watershed Address?

We are all familiar with our town and street address, but what about our watershed address? 

With the recent weather events and flooding, it is now more apparent than ever that what defines our location on this planet is not only our man-made address, but our place within a watershed. Everyone on the planet lives within a watershed. Perhaps it is on top of a hill, or in a valley, next to a river, or by a lake. Wherever we live, our watershed address tells us where the water comes from in our area, where it goes, and what might happen to it along the way.  

A watershed is an area of land that contains and filters water, from source to sink. The source is the place where a water system starts. For example, the source of the Hudson River watershed is a small lake on Mount Marcy in the Adirondacks, called Lake Tear of the Clouds.

The Hudson starts as a small rocky brook, and as it travels to lower elevations and meets tributaries it becomes wider and deeper, until eventually, it gets to its sink, the Atlantic Ocean.

In a watershed, the sink is the place of lowest elevation. Water always travels from a place of higher elevation to a place of lower elevation. There is a common misconception that rivers and streams always flow south. But there are plenty of waterways that flow north, as long as the direction north corresponds with a decrease in elevation.  

Your watershed address is defined by where the water around your home comes from, and where it goes.

Everybody has a major watershed address, as well as a sub-watershed address. My major watershed address is the Hudson River. Living on the western side of Westchester County, the water that flows over my lawn and down the hill eventually may end up in the Hudson River, after it travels through one of the reservoirs, wetlands or streams that will bring it finally to the Hudson River.

That is, if it does not enter into the bank of groundwater, get used by plants, or be evaporated into the clouds.  If you live on the eastern side of the county, chances are your major watershed address is the Long Island Sound. You can check out EPA’s Surf Your Watershed site for more information about your watershed.

Your sub-watershed address is the source closer to your home. For me, it is the Croton Reservoir. There is a stream in my backyard that flows directly into the reservoir, and the runoff from my local area washes into that stream.

You can find more about your sub-basin by observing the slope of the land around you and how it relates with the waterways and wetlands adjacent. You can also go onto www.usgs.gov to pull up a topographical map of your location. This map will show you elevation points and help you determine the area of lowest elevation near your home.

It is important to remember that a watershed does not consist only of streams, lakes and swamps. A considerable amount of the water within our watersheds is located under the ground, as groundwater. The water under the ground, although often ignored because it is not visible, is vital to life. It feeds the wetlands that become our rivers, and is a source of drinking water.

I like to think of groundwater metaphorically like a jar. There is a certain amount of space underground that can be used for water storage, in the crevices and cracks within bedrock. As it rains, the groundwater jar fills up as water soaks into the ground through impervious surfaces such as forests and lawns. The groundwater jar empties slowly into streams or wetlands, and sometimes is emptied by wells.

If the rains are heavy and the groundwater ‘jar’ is already almost full, like in the last few weeks, the ground will become saturated and the jar will overflow, onto streets, into basements, and rushing into rivers.

In places like New York City, where there is little impervious surface left to allow rainwater to soak into the ground, the groundwater jar has nearly emptied.

Back when Native Americans hunted and fished on the island of Mannahatta, there were springs and natural water sources. Nowadays because of all of the development, New York City gets its drinking water from reservoirs located East-of-Husdon (about 10%) and reservoirs in the Catskills (about 85%). For more information about the New York City Drinking Watershed, visit the NYC DEP website.

In our area more than many others, it is important to remember that we share our watershed address with many other people. We are all connected by the flow of water. What one person does near the source can affect many others near the sink. We all have common consideration for our neighbors when we keep our pets on our property and stay quiet at night, but even more important is consideration of our watershed neighbors.

We can be considerate of our watershed neighbors, and help the earth, by not dumping into street drains, by using fertilizers with low phosphate levels, by planting flowers or trees instead of lawn, by not dumping into local wetlands, by minimizing the amount of impervious surface (driveway, cement) on our property, and by keeping our septic systems maintained and without leaks.