Transcript Why Care for the Watershed?

Why Care for Your Watershed?
Charleston, OR
The Oregon Coast Education Program
Watersheds provide water – and the
resources that water provides.
What Is
A Watershed?
... the area of land that
drains to a particular
point along a stream.
(Lane Council of
Governments)
… a ridge of high land
dividing two areas that are
drained by different river
systems. (Free Online
Dictionary)
… the land that surrounds and
drains rain, snowmelt, and other
water into a lake, pond, wetland,
stream, or river. (Minnesota River
Basin Data Center)
Most watersheds combine urban, rural,
natural & cultural elements
Parts of a
Watershed
Sub-basin or tributary watershed
Some typical features of watersheds
Precipitation,
surface flow,
ground water flow,
evaporation, and
transpiration of
water by plants
recycle water
through the
atmosphere, soils,
streams, and
bedrock
formations.
Common Ways People Change Watersheds
• Alter land cover and use (e.g., agriculture,
•
•
•
•
urban development)
Simplify surface pathways (e.g., drainage
ditches, canals, storm sewers)
Add things to water (e.g., fertilizers, sewage)
Increase runoff and sedimentation from
parking lots, roofs, roads
Increase risk of flooding
The Stream Margin:
A Vital Transition Zone
Riparian Area:
The area adjacent to a
lake or stream,
consisting of the area of
transition from an
aquatic ecosystem to a
terrestrial ecosystem.
Riparian Area Functions
Water Quality
Flood control
Aquatic habitat
Wildlife Habitat
Aesthetic value
Estuaries
& Watersheds
Estuaries are the places
where The ebb and flow
of the tides connect a
watershed to the ocean.
Surface Water: The Visible Watershed
• In the United States, 60% of all
public water supplies (including
Bandon’s) use surface water…
• In Oregon, surface water is really
important. Public water suppliers
use 5 times more surface water
than ground water
• In Oregon Surface water is
especially important because
salmon are also important to us.
• Virtually all municipal waste water
is discharged into surface water…..
(Think about that for a moment!)
Ground Water:
The Watershed We Don’t See
• Important water supply for
Oregonians. 40 percent of public
water supplies use wells.
• More than 600,000 Oregonians
provide their own drinking water and
70% of this water comes from
private wells.
• Many Oregon rivers and streams
depend on ground water, especially
in summer, when ground water
influences stream flow, water
chemistry and water temperatures.
• In some streams ground water is
essential to the survival of salmon
and other fish that depend on cold
water.
Ground Water:
The Watershed We Don’t See
• Over the last 20 years, ground
water studies and monitoring of
public water supplies revealed
impairment or reason for concern in
35 of 45 ground water study areas
in Oregon.
• Nitrate is the most common
contaminant in ground water.
• 16% of 2,187 wells sampled
exceed the EPA drinking water
standard for nitrate, a form of
Nitrogen.
Nitrogen, Nitrates & Nitrites
• Nitrogen, a common element, is
necessary for life. It is used to build
proteins.
• Earth’s atmosphere is 70% nitrogen.
• Before living organisms can use it,
nitrogen gas must be chemically “fixed”
to make ammonia, nitrates and amino
acids.
Nitrogen-fixers:
• alder trees
• blue-green algae
• beans and leguminous plants
• soil bacteria
• lightning and cosmic rays!
• Nitrification:
– When plants and animals die, their
proteins are broken down by bacteria
to form ammonia.
– Other bacteria convert the ammonia
to nitrite.
– Still other bacteria convert the nitrite
to nitrate, which fertilizes new plant
growth.
• Denitrification:
– Bacteria and fungi break down
nitrates to obtain oxygen and return
nitrogen gas to the atmosphere.
Other Sources of Nitrates
In Ground Water & Surface Water..
• Chemical Fertilizers including
– agricultural fertilizers;
– turf grass fertilizers;
• Septic tank effluent or leaking sewer lines;
• Animal waste Including:
– Pets
– Domestic animals
– Wild animals
• Can you see the human connections?
• It is really difficult to remove Nitrates from water
Too much nitrogen?
Adding too much nitrate (and
phosphate) to the water is
called eutrophication: a
cause of algae and plankton
blooms.
Algae blooms use up the
oxygen on the water leading
to fish kills, dead zones, and
the production of more
nitrates.