Unit 6
Study
Guide
1. Define a watershed and what does it
mean that we live in the Chesapeake Bay
Watershed?
 A watershed is the area of land where water flows
across, under, and through on its way to one large body
of water.
 The water moves from a higher elevation to a lower
elevation, picking up contaminants that affect the
habitat and water quality of the watershed.
 Living in the Chesapeake Bay Watershed means that
the water that moves across or below the land will
eventually drain into the Chesapeake Bay.
2. Most of the water in Loudoun
County flows into which river that is a
tributary to the Chesapeake Bay?
Potomac River
Which 6 states, along with the
District of Columbia make up the
Chesapeake Bay Watershed?
Virginia
Pennsylvania
Maryland
New York
Delaware
District of
Columbia
West Virginia
4. Define tributary and name three
tributaries (other than the Potomac) to the
Chesapeake Bay
 Tributary = any smaller river or stream that flows into a
larger body of water.
 Examples
 Susquehanna River
 Potomac River
 James River
 York River
 Rappahannock River
 There are about 150 major rivers (tributaries) that
contribute fresh water to the Chesapeake Bay.)
5. What do we call the rainfall that
flows over the ground instead of
soaking into the ground?
Runoff
6. Give two reasons why water
runoff is a problem for our
watershed.
 Excess sediments can passed through a watershed
 Pollutants (such as nutrients) can be passed through
a watershed.
7. Which tributary to the Chesapeake
Bay is the largest and provides the
majority of fresh water?
 The Susquehanna River. It is believed
to have flooded to form the bay about
12,000 years ago.
8. What do we call the highest point of
elevation in a watershed that divides
one watershed from another?
A divide
9.What is a floodplain and where is
it located?
 Floodplain = part of a river or
stream valley covered by water
during a flood.
It is located on either side of the
river or stream (running parallel to
the body of water).
10. Rocks experience changes in
temperature that causes them to crack.
Is this an example of erosion or
weathering?
Physical Weathering
11. Acid rain eats away at statues.
Is this an example of physical or
chemical weathering?
Chemical Weathering
12. What is the difference
between erosion and weathering?
 Weathering is the process of breaking
down rock or soil into smaller pieces.
 Erosion occurs when rock and soil are
moved from one place to another due
to wind, water, glaciers, humans, or
animals.
13. Which type of load causes
turbidity in water?
Suspended load causes turbidity.
“Load” in a river is another word for
sediment that is carried by a river.
14. What materials are sediments
made of?
Sediments are made up of
materials such as sand, clay,
silt, or smaller rock
fragments.
15. Explain how vegetation
along a stream affects runoff.
Vegetation slows runoff, absorbs
excess nutrients and water.
16. If a river has more energy what
happens to the landscape and the
turbidity of the water?
 Faster moving rivers cause more
erosion and carry more sediment, thus
increasing turbidity. Faster moving
rivers can carry larger sediment and
rivers tend to be straighter.
17. What is a wetland and how are
the three types classified (defined)?
A wetland is an area where land is
usually covered by water all year or
for varying periods of time during
the year.
Wetlands are classified by the type
of vegetation existing there.
18. Why are wetlands called a
transition zone?
Wetlands are called transition
zones because it is where the land
meets the water in an estuary.
19. What are 3 types of wetlands?
Marsh - grasses, soft stemmed
plants and reeds
 Bog - thick organic matter, such
as peat
Swamp -trees
20. What are 3 functions of a wetland
that helps the health of the Chesapeake
Bay?
Wetlands perform the following functions:
1) Trap sediment
2) Filter pollutants
3) Provide a habitat
4) Prevent erosion
21. What is an estuary and what
makes it unique?
 An estuary is a semi-enclosed body of water
where freshwater from rivers and streams
meet saltwater from the ocean.
 Estuaries are unique, because the salinity
levels change and the animals that live there
must adapt. Estuaries are also nurseries for
animals.
22. Name three things that have caused the
water quality in the Chesapeake Bay
(estuary) to decrease.
1. Excess nutrients from fertilizers, such as nitrogen and
phosphorous compounds, in the water (main cause).
These nutrients cause algae to grow out of control.
This makes it hard for underwater grasses to grow,
reducing the supply of oxygen to decrease.
2. The destruction of natural habitats for plants and
animals, including wetlands.
3. Toxic chemicals and increased sediment (dirt) in the
water.
23. What is the largest estuary
in the US?
Chesapeake Bay.
24. Give two reasons estuaries are
important for humans.

Cultural benefits (recreation; scientific knowledge)

Economic benefits (tourism, commercial activities)

Shipping, transportation and other industry
25. Completely explain how oxygen can be
depleted (used up) in a body of water.
There are two basic reasons.

Turbidity blocks sunlight from reaching SAV.
 Excess nutrients cause algae to bloom, which causes
turbidity. When the algae dies and decays,
bacteria that decompose the algae uses oxygen.
26. Define salinity and explain how
the levels can change in an estuary.
 Salinity is the amount of salt dissolved
in the water. Excessive rain can
decrease the salinity and drought can
increase the salinity.
27. How can pH be measured and
what is the pH scale for an acid, base,
and a neutral substance?
 The pH level can be measured using pH test kits or
pH meters.
 The pH scale is a number scale between 0- 14.




An acid has a pH of 0 to less than 7
A base has a pH greater than 7 to 14
Neutral substances have a pH of 7
Pure water has a pH of 7.
28. What problems do farms
create for the watershed?
 Runoff from farms and agricultural areas allow excess
nutrients and sediment to get into the watershed.
29. What is the difference between point
and non-point source pollution and give two
examples for each.
 Point source pollution = pollution comes from one polluter
and can be easily identified .
 Examples: an industry is releasing toxic waste or a sewage
treatment plant is leaking
 Non-point source pollution is not easily identified,
because there may be many contributors to the pollution
 Examples: fertilizers, nutrients, pesticides from farms; oil
and paint from housing developments or city areas; spilled
gasoline at gas stations
 Runoff can be reduced by adding materials, such as
vegetation, wood chips or gravel to allow the water to soak
into the ground.
30. List three ways non-point
source pollution can be reduced.
 Using cleaning products and
fertilizers without phosphorus
 Testing your car for oil leaks
 Manure containment on farms
 Silt fences around construction sites
31. How much of the earth’s water
is salt water (percent)?
About 97% of
Earth’s water is
saltwater.
 Less than 1% of all the water
on Earth is non-frozen,
available fresh water.
32. Define abiotic factors and give
three examples.
 Abiotic factors include the physical,
non-living, factors that influence the
living organisms in an ecosystem.






temperature
soil
light
pH
salinity
turbidity, etc.
33. Of all the water quality tests,
which one is a test of a biotic factor ?
Macro-invertebrate tests would be a
biotic factor water quality test.
Macro-invertebrate Sampling
34. Why is rain normally acidic? What
creates acid rain, which is considered
unusually acidic?
 Rain is normally acidic because carbon
dioxide combines with the water in the air to
form carbonic acid.
 Acid rain is rain that is exceptionally acidic
due to additional compounds added to the
atmosphere (carbon dioxide – carbonic acid),
(sulfur dioxide – sulfuric acid), and (nitrous
oxide – nitric acid)
35. What is a SAV, and give two reasons
they are important to the Bay.
 SAV = submerged aquatic vegetation.
 SAVs provide a protective environment for
aquatic organisms
 SAVs produces oxygen through
photosynthesis.
36. Why are oysters important to
the Bay’s health?
 Oysters filter the water in
the bay, clearing it of
sediments and pollutants.
37. Name and define three types
of pollutants.
 Sediment pollution – sediments suspended in the
water
 Toxic pollution – Gasoline, oil, pesticides, industrial
discharge, etc.
 Thermal pollution – hot water resulting from water
runoff from paved surfaces
38. Which water quality test
(standard) is the most important test
for the health of a water ecosystem?
 Dissolved oxygen is the most important test for the
health of a water ecosystem.
39. What is a nutrient, how does it get
into the water, where does it come
from, and what does it cause?
 A nutrient is a compound (nitrates and
phosphates) that is necessary for all living
organisms.
 Nutrients get into the water through runoff
 Nutrients come from fertilizers, animal wastes,
and detergents (phosphates)
 Nutrients cause algae to bloom.