Watershed Systems

Health of Ecosystems

  • Factors that can affect health:

  • Ecosystems contain abiotic and biotic factors that affect water quality

    • Biotic factors are living, including organisms

    • Abiotic factors are nonliving

      • Sunlight

      • Soil

      • Water supply

      • Topography

      • Soils

      • Dissolved oxygen

      • Air quality

      • Salinity

      • Water chemistry

Many environmental processes are natural, but humans can alter these natural processes:

  • release pesticides/herbicides/fertilizers and alter the chemicals in the ecosystem

  • flood protection/wetland loss

  • plowing fields (accelerates erosion)

  • planting trees (slows erosion)

Watersheds

  • What are watersheds?

    • Land that water flows across or through on its way to a stream, lake, wetland, or other body of water

    • Areas of high elevation, like ridgelines and divides, separate watersheds

    • Arrangements of river systems

  • VA’s Watersheds

    • 3 major regional watershed systems lead to:

      • Chesapeake Bay (pictured on left)

        • 6 States (New York, Penn., Maryland, Delaware, West Va., Virginia)

        • 6 Major river systems

          • Susquehanna River

          • Shenandoah River

          • Potomac River

          • Rappahannock River

          • York River

          • James River

      • North Carolina sounds

      • Gulf of Mexico

Rivers and Tributaries

  • River systems are made up of tributaries of smaller streams that join along

  • What are tributaries?

    • Tributaries are rivers or streams that enters a larger body of water, especially a lake or river

  • Rivers and streams generally have wide, flat, border areas, called flood plains (water spills out at times of high flow)

  • Rivers and streams carry and deposit sediment

Wetlands

  • transition zone between dry land and bodies of water (rivers, lakes, or bays)

  • regulate runoff by storing flood waters

  • reduce erosion by slowing down run-off

  • maintain water quality by filtering sediments, trapping nutrients, and breaking down pollutants

  • recharge groundwater

  • provide food, shelter for wildlife

  • provide nesting and resting areas for migratory birds

Estuaries

  • Saltwater and freshwater mix (water is called “brackish”)

  • provide habitat for many organisms and serve as nurseries

  • Example: Chesapeake Bay - largest estuary in the contiguous United States (and one of the most productive) - covers 60% of VA

  • Estuaries can also be called bays, lagoons, harbors, inlets, or sounds

  • Humans rely on estuaries for recreation, tourism, fisheries, and transportation

  • Support communities of organisms

Chesapeake Bay

Conservation and Water Quality

  • Monitoring water quality is an important way for scientists to determine ecosystem and watershed health

    • Scientists collect water samples to analyze chemical and/or biological parameters

    • Parameters include (there are many more):

      • pH, temperature

      • salinity

      • dissolved oxygen

      • turbidity (cloudiness)

      • presence of macroinvertebrate organisms

      • Chemical components and nutrients

  • Many governmental and local efforts to conserve watershed ecosystems (like the Chesapeake Bay)

  • Ways to help: advocacy, working with educational programs, litigation/laws, restoration, and volunteers picking up trash

Pollution and Safety Issues

  • Nonpoint Source Pollution - does not result from a single location

    • Examples: runoff, drainage or seepage, when rainfall carries contaminants, such as fertilizers and pesticides, oils, grease and trash to bodies of water

  • Point Source Pollution - pollution that flows from pipes or comes from specific points

    • Examples: industrial plants, sewage treatment plants, storm water drains, pipes

  • This damages both human health and the health of organisms in these bodies of water, compromising safety and water quality

Quiz

Check your answers!

1.D

2.B

3.C

4.A,C

5.A,B,C,D,E

6.B,C,D

7.A,C,D