NR 220 Watershed Study Guide: 100+
Questions & Answers|| Updated
2025/2026 A+ Graded||100%
Guaranteed Pass!!!
Section 1: Fundamental Concepts & Definitions
1. What is a watershed?
ANSWER ✓ A watershed is the total land area that drains all precipitation (rain, snow,
sleet) to a common outlet, such as a stream, river, lake, or ocean. It is a topographically
delineated area where all water within it flows to the same point.
2. What is another term for 'watershed'?
ANSWER ✓ "Catchment" or "drainage basin." The term used can be regional; for
example, "watershed" is common in North America, while "catchment" is more common
in Europe and Australia.
3. What is the defining feature that separates two adjacent watersheds?
ANSWER ✓ A ridge or area of high elevation called a "divide." The Continental Divide is
the most famous example, separating watersheds that drain to the Pacific Ocean from
those that drain to the Atlantic and Arctic.
4. What is the difference between a catchment and a subwatershed?
ANSWER ✓ A catchment is a general term for any area that collects water. A
subwatershed is a smaller, nested watershed within a larger watershed, often used for
more detailed planning and management.
5. What is the ultimate receiving body for all watersheds?
ANSWER ✓ The ocean. All land-based watersheds ultimately drain to an ocean, with the
,exception of closed internal basins (e.g., the Great Salt Lake) which drain to an inland
water body.
6. What is hydrology?
ANSWER ✓ The scientific study of the movement, distribution, and quality of water on
Earth, including the hydrologic cycle, water resources, and environmental watershed
sustainability.
7. What is the fundamental unit of study in watershed management?
ANSWER ✓ The watershed. It is considered the most logical and effective unit for
managing water resources because it integrates all the physical, chemical, and biological
processes within a defined geographical area.
8. Define "riparian area."
ANSWER ✓ The interface between land and a river or stream. These are vegetated areas
(riparian zones) immediately adjacent to water bodies that significantly influence the
health of the aquatic ecosystem.
9. What is a floodplain?
ANSWER ✓ A flat area of land adjacent to a stream or river that experiences flooding
during periods of high discharge. It is a natural part of a river's system for storing excess
water.
10. What is an aquifer?
ANSWER ✓ An underground layer of water-bearing permeable rock, rock fractures, or
unconsolidated materials (gravel, sand, silt) from which groundwater can be extracted.
Section 2: The Hydrologic Cycle & Water Movement
11. What is the hydrologic cycle?
ANSWER ✓ The continuous movement of water on, above, and below the surface of the
, Earth, including processes like evaporation, condensation, precipitation, infiltration, and
runoff.
12. What is the primary energy source that drives the hydrologic cycle?
ANSWER ✓ Solar energy from the sun, which provides the heat necessary for
evaporation.
13. What is the difference between evaporation and transpiration?
ANSWER ✓ Evaporation is the process where liquid water becomes vapor from surfaces
like soil, water bodies, and pavements. Transpiration is the release of water vapor from
plants. Combined, they are called "evapotranspiration."
14. What is infiltration?
ANSWER ✓ The process by which water on the ground surface enters the soil. The rate
of infiltration is influenced by soil composition, saturation, land cover, and slope.
15. What is the difference between infiltration capacity and infiltration rate?
ANSWER ✓ Infiltration capacity is the maximum rate at which soil can absorb water.
Infiltration rate is the actual rate at which water is entering the soil at a given time.
16. What is runoff?
ANSWER ✓ The flow of water that occurs when the rate of precipitation exceeds the
infiltration capacity of the soil, and water moves over the land surface towards streams.
17. What are the three main types of runoff?
ANSWER ✓ 1) Surface runoff (overland flow), 2) Subsurface flow (through the upper soil
layers), and 3) Groundwater flow (baseflow through aquifers).
18. What is the term for water that is stored in the pores of soil and rock?
ANSWER ✓ Soil moisture (in the unsaturated zone) and groundwater (in the saturated
zone/aquifer).
Questions & Answers|| Updated
2025/2026 A+ Graded||100%
Guaranteed Pass!!!
Section 1: Fundamental Concepts & Definitions
1. What is a watershed?
ANSWER ✓ A watershed is the total land area that drains all precipitation (rain, snow,
sleet) to a common outlet, such as a stream, river, lake, or ocean. It is a topographically
delineated area where all water within it flows to the same point.
2. What is another term for 'watershed'?
ANSWER ✓ "Catchment" or "drainage basin." The term used can be regional; for
example, "watershed" is common in North America, while "catchment" is more common
in Europe and Australia.
3. What is the defining feature that separates two adjacent watersheds?
ANSWER ✓ A ridge or area of high elevation called a "divide." The Continental Divide is
the most famous example, separating watersheds that drain to the Pacific Ocean from
those that drain to the Atlantic and Arctic.
4. What is the difference between a catchment and a subwatershed?
ANSWER ✓ A catchment is a general term for any area that collects water. A
subwatershed is a smaller, nested watershed within a larger watershed, often used for
more detailed planning and management.
5. What is the ultimate receiving body for all watersheds?
ANSWER ✓ The ocean. All land-based watersheds ultimately drain to an ocean, with the
,exception of closed internal basins (e.g., the Great Salt Lake) which drain to an inland
water body.
6. What is hydrology?
ANSWER ✓ The scientific study of the movement, distribution, and quality of water on
Earth, including the hydrologic cycle, water resources, and environmental watershed
sustainability.
7. What is the fundamental unit of study in watershed management?
ANSWER ✓ The watershed. It is considered the most logical and effective unit for
managing water resources because it integrates all the physical, chemical, and biological
processes within a defined geographical area.
8. Define "riparian area."
ANSWER ✓ The interface between land and a river or stream. These are vegetated areas
(riparian zones) immediately adjacent to water bodies that significantly influence the
health of the aquatic ecosystem.
9. What is a floodplain?
ANSWER ✓ A flat area of land adjacent to a stream or river that experiences flooding
during periods of high discharge. It is a natural part of a river's system for storing excess
water.
10. What is an aquifer?
ANSWER ✓ An underground layer of water-bearing permeable rock, rock fractures, or
unconsolidated materials (gravel, sand, silt) from which groundwater can be extracted.
Section 2: The Hydrologic Cycle & Water Movement
11. What is the hydrologic cycle?
ANSWER ✓ The continuous movement of water on, above, and below the surface of the
, Earth, including processes like evaporation, condensation, precipitation, infiltration, and
runoff.
12. What is the primary energy source that drives the hydrologic cycle?
ANSWER ✓ Solar energy from the sun, which provides the heat necessary for
evaporation.
13. What is the difference between evaporation and transpiration?
ANSWER ✓ Evaporation is the process where liquid water becomes vapor from surfaces
like soil, water bodies, and pavements. Transpiration is the release of water vapor from
plants. Combined, they are called "evapotranspiration."
14. What is infiltration?
ANSWER ✓ The process by which water on the ground surface enters the soil. The rate
of infiltration is influenced by soil composition, saturation, land cover, and slope.
15. What is the difference between infiltration capacity and infiltration rate?
ANSWER ✓ Infiltration capacity is the maximum rate at which soil can absorb water.
Infiltration rate is the actual rate at which water is entering the soil at a given time.
16. What is runoff?
ANSWER ✓ The flow of water that occurs when the rate of precipitation exceeds the
infiltration capacity of the soil, and water moves over the land surface towards streams.
17. What are the three main types of runoff?
ANSWER ✓ 1) Surface runoff (overland flow), 2) Subsurface flow (through the upper soil
layers), and 3) Groundwater flow (baseflow through aquifers).
18. What is the term for water that is stored in the pores of soil and rock?
ANSWER ✓ Soil moisture (in the unsaturated zone) and groundwater (in the saturated
zone/aquifer).
