1. Hydrology Unit Test
Study Guide Answer Key

2. 1. Approximately what percentage of Earth’s water is fresh water?

3. 2. Completely label this water cycle diagram:
Precipitation: when the droplets become too heavy and fall as rain and snow
Condensation: Gas becoming liquid: water vapor cools to become droplets which adhere to one another and form clouds
Evaporation: Liquid becoming
gas (water vapor): This can include transpiration from plants & trees.
Infiltration: water on the ground surface enters permeable soil & rock
Run-off: precipitation moves across the earth, moving by gravity
**Some resources include COLLECTION: oceans and lakes ‘collect’ water and keep it until evaporation occurs

4. 2. Water that falls to Earth as rain, snow, sleet, or hail is called what?
Precipitation
3. Is the total amount of water on Earth increasing, decreasing or
staying fairly constant?
4. Water that fills the cracks and spaces
in underground soil and rock layers is
called what? Groundwater
5. The streams and small rivers that feed into a main river are called tributaries.

5. 5. A river system is made up of a river and its tributaries.
6. Where can you find fresh still water? In lakes and ponds
The land that supplies water to a
river system is called its watershed.
Materials that allow water to pass through them easily are
considered to be permeable.

6. water that then rises to the surface
When the demand for water is greater than the supply, the
surrounding area experiences a water shortage.
10. Using less water is one way to practice water conservation.
Sources of pollution that cannot be easily identified are called
nonpoint sources.
Yellowstone National Park contains many
hot springs and geysers. What would you
expect to find beneath the ground in this
area that causes the water to be heated?
hot, molten rock which heats
water that then rises to the surface

7. Plants use water to undergo photosynthesis. They V
Plants use water to undergo photosynthesis. They
also release water into the atmosphere. Plants
contribute to which part of the water cycle?
Evaporation….transpiration is essentially
evaporation of water from plant leaves.
The land area that causes water to drain into
two separate river systems is called a divide.
Groundwater is often reached by people through drilling a well
down into the aquifer.
22. The energy for the water cycle originally comes from the sun.

8. Water moves from the atmosphere to Earth’s surface as rain, snow, and
other forms of precipitation.
Most of Earth’s fresh water is
in the form of polar ice sheets.
Fresh water found in soil and rock layers below Earth’s surface is called
groundwater.
27. A ridge of land that separates two watersheds is called a(an) divide.

9. saturated zone. The area of soil in which the pores are
totally filled with water is called the
saturated zone.
The top of the saturated zone is
called the water table.
Industries that reduce water use, recycle water, and reuse water are
practicing water conservation.
The addition of any substance to water that has a negative effect on living
things is called pollution.

10. Farming, new organisms, land development
A widely spread source of pollution that can’t be tied to a specific point of
origin is a(an) nonpoint source.
A well in which groundwater rises to the
surface due to pressure is called
an artesian well.
34. A lake that stores water for human use is called a reservoir.
Name 3 human activities that threaten the Everglades.
Farming, new organisms, land development

11. marsh – grassy; covered with shallow water
36. Name 3 type of freshwater wetlands.
bog – acidic water; mosses thrive
marsh – grassy; covered with shallow water
swamp – flooded forest; trees & shrubs
37. Are the Florida Everglades considered to be a bog, a marsh, or a swamp?
How do wetlands help control flooding?
They absorb runoff from heavy rains.
39. What are two factors that make the Florida Everglades a great habitat for
many living things? Sheltered water & large supply of nutrients

12. a filtering ‘net’ that captures sediment, waste materials, and
How do wetlands serve as a filtering system? Plants roots create
a filtering ‘net’ that captures sediment, waste materials, and
chemicals, preventing them from entering groundwater
41. How do wetlands help to control flooding?
Wetlands capture and hold on to water much like a sponge.
42. What is an aquifer? An underground layer of rock or sediment
that holds water.
How is a lake different than a pond? Lakes are deeper and larger;
sunlight does not reach the bottom of a lake.

13. agriculture consumes 80% of the nation's freshwater – more
What is the most wasteful use of water in the United States?  
agriculture consumes 80% of the nation's freshwater – more
than twice the water used by industry
At which ocean feature would you find
the greatest amount of water pressure?
What are the three major steps in the water cycle?
Evaporation  Condensation  Precipitation
Deep-Ocean Trench

14. the sun, the moon, and the Earth
47. Make a table showing how all Earth’s water is distributed.
48. Which of the sea floor features is made up of a range of mountains that wind through the ocean? the mid-ocean ridge
Tides are caused by interactions
between what astronomical bodies?
the sun, the moon, and the Earth
A large stream of moving water that flows through the oceans is
called a(an) current.
Salt Water
Fresh Water
97%
3% (2% = ice; 1% = liquid {rivers, lakes, groundwater, etc.})

15. The abyssal plain is a smooth, nearly flat region of ocean floor
covered with layers of mud and silt.
Beyond the edge of the continental shelf lies the open ocean zone,
the deepest and darkest area of the ocean.
Which letter identifies the continental shelf? A
33. Identify feature E. Volcanic Island
What is the feature labeled C? deep-ocean trench
Identify the ocean feature labeled G.
Abyssal plain
36. What is the feature labeled D? Mid-Ocean Ridge
B = continental slope F = seamount

16. A “Tides” Cloze Activity
The daily rise and fall of Earth’s waters on its coastlines are called tides. As the tide comes in, the level of the water on the shore gradually increases. At the highest point, it is called high tide. Then the water gradually goes back out again to the lowest point, called low tide. Tides are caused by the interaction of the Sun, the Moon, and the Earth. The gravity of the moon pulls on Earth’s water, creating a bulge of on the side of Earth closest to the moon and on the opposite side of Earth as well. Because Earth rotates on its axis every 24 hours, there are 2 high tides and 2 low tides each day. The high tides are about 12 hours (time) apart.

17. Changes in the positions of Earth, the moon, and the sun affect the heights of the tides during a month. When the Earth, the moon, and the sun are positioned in a straight line, you will see the greatest range between high and low tide. This is called spring tide. When the moon, the moon and the sun are positioned at right angles to each other, you will see a tide with the least difference between low and high tide. This is called neap tide.

18. Good luck on the test!