Core Principle 1: Watersheds are natural systems that we can work with

Human Factors at Work

Working with your watershed also means understanding how most human activities in the watershed can occur in harmony with natural processes. Communities located along streams and rivers, for example, are faced with very basic choices: they can learn how the river functions and learn to draw benefits from it while staying out of harm's way—or, they can try to significantly change the river's behavior in order to accomplish their plans. It may be feasible to change the way a river acts, but this usually means taking on costly and never-ending maintenance of those man-made changes; and, despite all the maintenance, communities may remain still vulnerable to floods and other disasters. In contrast, a community that has made sensible decisions on activities near the river can avoid a costly maintenance burden while sustaining their community's use and enjoyment of a healthy river system.
In which type of community would you rather live and pay taxes?

How do you get oriented to what's happening in your watershed? Again, one place to begin a simple screening for potential stressors is Surf Your Watershed. After choosing the watershed you're interested in, the first page summarizes important statistics that describe the watershed such as:

• size of the watershed
• population
• current land uses by percentages
• counties in the watershed

By clicking on the words highlighted in blue on this page, you can get more detailed information about potential water quality or habitat stressors in the watershed. For example, you can find out what NPDES (PCS) Facilities or Toxic Release Sites are in the watershed.

If you want to understand where these and other potential stressors are in the watershed, you query the database for information such as:

• Population density
• Major roads
• Drinking water supplies
• NPDES sites
• Toxic Release Sites
• Superfund Sites

BASINS software can then be used to produce maps spatially illustrating this information. BASINS is a multipurpose environmental analysis system developed for EPA to assist regional, state, and local agencies in performing watershed and water quality-based studies. BASINS integrates a geographical information system (GIS), national watershed data, and modeling tools into one powerful package.

Maps and other valuable sources of land use and land cover information may be available through your local government offices. You can also turn to a USGS topo map to get a sense of where the farm, mining, and forest land is in the watershed.

Why is it important to know about these human activities and where they occur in the watershed? These human forces interact with the natural forces to directly shape the condition of the land and water. For example,

• increasing impervious surfaces in the urban areas leads to increased water and contaminant runoff;
• removing vegetation along drainage areas and increased stormflows lead to erosion of soils which can change the landscape to more arid conditions;
• increasing the velocity of the water and contaminants it contains can be lethal to living things
• or it can create health hazards, reducing our quality of life.

Once you've conducted a simple screening for potential stressors, you have a better sense of where to do more in-depth investigations, including getting out in the watershed to conduct stream walks, windshield surveys, and strategic water quality sampling.

So watersheds are natural systems we can work with because

• they are practical, tangible management units that people understand, and
• they help us understand and appreciate nature's interrelated processes and how our actions can be tailored to complement rather than impact them.