Watersheds and Water Quality

It’s usually difficult to see a
watershed unless, you’re standing on top of a hill or looking down from an airplane. Then you can see all the hills and valleys that drain water into a stream, the streams flowing into rivers and where rivers flow into lakes,bays, and estuaries. (Fig. 3.1) A watershed is all the land from which water drains into a specific body of water. Sections of connected hills and valleys form each watershed. Small watersheds make up a larger watershed.

Everyone lives in a watershed, and all land on Earth is part of some watershed. The land upstream from you makes up your watershed. As you move downstream, more streams and rivers flow together. Then all the new land drained by those new streams adds to your watershed. So your watershed depends on where you are along a stream, river, lake,estuary or ocean.

   Watch “What is a Watershed?”


   Look at North Texas Watershed 


Each watershed is divided into smaller regions (sub watersheds) that is part of a river basin, which is part of the whole watershed. In North Texas, your watershed address differs depending on your actual physical address. You may determine your watershed address, by utilizing this link:


For example, a watershed address might be:
 Student A
Lower Hickory Creek Sub Watershed
Hickory Creek-Little Elm Watershed
Elm Fork Trinity Sub River Basin
Trinity Water Basin
  Student B
Timber Creek Sub Watershed
Timber Creek-Elm Fork Watershed
Elm Fork Trinity Sub River Basin
Trinity Water Basin

Water quality within a particular watershed is greatly affected by the pollution that is collected as water travels through the watershed.

The quality of water is water’s fitness for a particular use. Water quality is determined by many factors, including pollution and life of aquatic organisms, and the long term health of ecosystems. Many testing and regulations go into keeping our State's aquatic resources available and clean enough to drink or use. We determine water quality using physical, chemical and biological tests. If water does become polluted, it affects aquatic life in many ways, including:
  • cloudy water blocks light and slows plant growth.
  • too much fertilizer causes overgrowth of algae.
  • toxic chemicals are poisonous to living things.
Many questions arise when thinking about water quality:
How does water’s temperature affect the amount of oxygen in it?  Cold water holds more oxygen.
How do humans affect water quality? Humans affect water quality by polluting or conserving water.

Christy Croll,
Sep 20, 2015, 10:24 AM
Christy Croll,
Sep 20, 2015, 10:25 AM