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
Links:
https://archive.epa.gov/water/archive/web/html/watersheds_index.html - Environmental Protection Agency is a great resource!
https://extension.psu.edu/watersheds-and-wetlands
https://www.solpass.org/science6-8-new/s6/standards6/standard_6-7.html?section=study-4
https://www.watereducation.org/aquapedia-background/tributaries
https://oceanservice.noaa.gov/facts/estuary.html
https://environment.des.qld.gov.au/management/water/health-indicators
https://www.lcps.org/cms/lib4/VA01000195/Centricity/Domain/3289/road%20map%20finished.pdf