Unit 1

Question 1

What is hydrology?

Answer 1

The science of water, tracking where it falls, flows, hides, or vanishes.

Hydrology encompasses both surface and underground water as well as atmospheric water vapor.

Question 2

What are the two main branches of hydrology?

Answer 2

• Scientific Hydrology
• Engineering Hydrology

Scientific hydrology focuses on theory, while engineering hydrology is practical and applied.

Question 3

What does scientific hydrology focus on?

Answer 3

Pure theory, chasing ‘why’ and ‘how’ for the sake of knowledge.

It is more academic and detached compared to engineering hydrology.

Question 4

What is engineering hydrology?

Answer 4

Applied hydrology focused on practical applications and solving real-world water issues.

It involves bending water to human needs and addressing challenges like floods and droughts.

Question 5

List three tasks of engineering hydrology.

Answer 5

• Estimate Water Resources
• Decode Processes
• Fight Problems

Each task involves specific methods and data to manage water effectively.

Question 6

What does estimating water resources involve?

Answer 6

Quantifying rivers, aquifers, and rain using data like MCM, TMC, and CGWB.

This is crucial for understanding available water supply.

Question 7

What processes does engineering hydrology decode?

Answer 7

• Precipitation
• Runoff
• Evapotranspiration

Understanding these processes helps in managing and predicting water flow.

Question 8

What are some problems that engineering hydrology aims to fight?

Answer 8

• Floods
• Droughts

Strategies to predict and manage these issues are essential for safety and sustainability.

Question 9

True or False: Engineering hydrology is only concerned with theoretical concepts.

Answer 9

False

Engineering hydrology is focused on practical applications and real-world issues.

Question 10

Fill in the blank: This book serves as a _______ for civil engineers dealing with water management.

Answer 10

[field manual]

It combines qualitative and quantitative approaches to water management.

Question 11

What is the main purpose of the book mentioned in the text?

Answer 11

To provide practical tools for managing water issues like floods and shortages.

It is designed for civil engineers working on infrastructure like dams and bridges.

Question 12

What is the significance of understanding hydrology in engineering?

Answer 12

It allows engineers to master water processes and effectively address challenges like floods and droughts.

Knowledge of hydrology is crucial for successful water management.

Question 13

What is transpiration?

Answer 13

Water’s escape act through plants, where roots suck it from the soil and it is released as vapor through leaves.

Transpiration is a biological process and is dependent on the presence of plants.

Question 14

What are the main components involved in transpiration?

Answer 14

Roots, soil, vapor, leaves, stomata.

Stomata are tiny pores on leaves that allow gas exchange.

Question 15

How is transpiration measured?

Answer 15

Indirection, as it is hard to isolate.

It represents a significant portion of water loss in ecosystems with vegetation.

Question 16

Define evapotranspiration.

Answer 16

The total water-to-vapor process, which includes both transpiration and evaporation.

Evapotranspiration is a key concept in understanding water cycles.

Question 17

What is evaporation?

Answer 17

The process of water lifting off surfaces like soil, puddles, lakes, and rivers, driven by heat, wind, and dryness.

Evaporation does not require any biological processes.

Question 18

What are PET and AET in the context of evapotranspiration?

Answer 18

PET (Potential Evapotranspiration) is the maximum possible under unlimited water; AET (Actual Evapotranspiration) is the actual amount given the available water.

These terms help in assessing water availability and loss.

Question 19

How do transpiration and evapotranspiration differ?

Answer 19

Transpiration is a subset involving only plants, while evapotranspiration includes both plants and abiotic surfaces.

Evapotranspiration is broader and encompasses all forms of water vaporization.

Question 20

In which environments does evaporation dominate?

Answer 20

Deserts.

In arid regions, evaporation plays a more significant role compared to transpiration.

Question 21

In which environments does transpiration dominate?

Answer 21

Jungles or areas with dense vegetation.

In these ecosystems, plants significantly contribute to water loss through transpiration.

Question 22

Why is understanding evapotranspiration important in hydrology?

Answer 22

It affects runoff, river health, and water budgets.

Tracking evapotranspiration is essential for managing water resources.

Question 23

True or False: Transpiration can occur without the presence of plants.

Answer 23

False.

Transpiration is exclusively linked to living plants.

Question 24

Fill in the blank: Evapotranspiration is the combination of _______ and evaporation.

Answer 24

transpiration.

This highlights the interconnectedness of biological and physical processes in the water cycle.

Question 25

What are the three key components in the cycle discussed?

Answer 25

Precipitation, runoff, evapotranspiration

Question 26

Define precipitation in the context of the cycle.

Answer 26

The input—rain, snow, whatever falls. It’s the fuel.

Question 27

What is runoff?

Answer 27

Water that bolts—rivers, floods, surface chaos.

Question 28

What does evapotranspiration (ET) refer to?

Answer 28

The vapor thief that feeds on precipitation.

Question 29

True or False: Precipitation benefits both runoff and evapotranspiration.

Answer 29

True

Question 30

How do precipitation, runoff, and evapotranspiration interact?

Answer 30

They drive and steal from each other in a zero-sum system.

Question 31

What happens when evapotranspiration is high?

Answer 31

Runoff decreases.

Question 32

What can heavy rain on dry ground lead to?

Answer 32

Runoff winning over evapotranspiration.

Question 33

Fill in the blank: Evapotranspiration _______ on precipitation.

Answer 33

sucks it up

Question 34

In what conditions does runoff take precedence over evapotranspiration?

Answer 34

Wet soil, cool air.

Question 35

What tools do engineers use to track the interaction between these components?

Answer 35

* CN (runoff potential) * AET (real vapor loss)

Question 36

What does a big storm hitting imply for the cycle?

Answer 36

Precipitation is huge; ET grabs what it can, infiltration takes a bite, and runoff claims the rest.

Question 37

What is the relationship between evapotranspiration and flood risk?

Answer 37

More ET means less flood.

Question 38

What is the relationship between runoff and vapor storage?

Answer 38

More runoff means less vapor or storage.

Question 39

Describe the dynamic between precipitation, runoff, and evapotranspiration.

Answer 39

They are rivals eating the same pie; when one grows fat, the other shrinks.

Question 40

What is meant by 'predatory balance' in the context of these components?

Answer 40

They clash and feed off each other in a competitive cycle.

Question 41

What is the first step of the hydrologic cycle?

Answer 41

Precipitation ## Footnote Includes rain, snow, and hail falling from clouds onto various surfaces.

Question 42

What processes are driven by precipitation?

Answer 42

* Runoff * Infiltration * Evapotranspiration (ET) ## Footnote Precipitation acts as the starting point for these processes.

Question 43

What is interception in the context of the hydrologic cycle?

Answer 43

Water caught by plants, leaves, roofs before it hits the ground ## Footnote Delays infiltration and runoff, with some water evaporating back.

Question 44

What factors dictate the amount of water that infiltrates into the soil?

Answer 44

* Available moisture content (AMC) * Capillary number (CN) * Soil type (pervious material) ## Footnote These factors influence how much water sinks versus stays on the surface.

Question 45

What is transpiration?

Answer 45

Plants pulling water from soil and exhaling it as vapor ## Footnote It is part of the evapotranspiration process.

Question 46

What drives transpiration in plants?

Answer 46

* Sun's heat * Plant health ## Footnote No infiltration means no transpiration can occur.

Question 47

What is evaporation from land?

Answer 47

Water lifting off bare soil, puddles, and surfaces without the need for life ## Footnote It feeds clouds and combines with transpiration to form total ET.

Question 48

What is surface runoff?

Answer 48

Water racing off into rivers, streams, and floods ## Footnote It occurs when infiltration and ET do not capture all the water.

Question 49

What is the largest source of evaporation in the hydrologic cycle?

Answer 49

Evaporation from the ocean ## Footnote It significantly contributes to global evapotranspiration.

Question 50

What is groundwater flow?

Answer 50

Water creeping underground, fed by infiltration ## Footnote It is vital for maintaining streams and ocean levels.

Question 51

What is deep percolation?

Answer 51

Water plunging deeper into aquifers and rock fractures ## Footnote It is part of infiltration's long-term process of recharging water reserves.

Question 52

Fill in the blank: The hydrologic cycle is also known as the _______.

Answer 52

Water cycle ## Footnote It describes the continuous movement of water on, above, and below the Earth's surface.

Question 53

True or False: Evapotranspiration (ET) is the sum of evaporation and transpiration.

Answer 53

True ## Footnote ET combines both processes to represent total water loss to the atmosphere.

Question 54

What is the hydrologic cycle?

Answer 54

Water’s endless war—shapeshifting (liquid, solid, gas) and moving relentlessly across oceans, land, and air.

Question 55

Where does the hydrologic cycle start?

Answer 55

Oceans—solar radiation rips water into vapor via evaporation (step 7), the biggest ET source.

Question 56

How does vapor become clouds?

Answer 56

Winds haul ocean vapor skyward, forming clouds that move over land.

Question 57

What losses occur during precipitation?

Answer 57

Mid-air evaporation and interception by plants or roofs (step 2) steal water before it lands.

Question 58

What are the three fates of water hitting land?

Answer 58

Infiltration (sinks into soil), evapotranspiration (stolen by sun and plants), runoff (races to streams).

Question 59

What controls infiltration?

Answer 59

Soil type (pervious material), wetness (AMC), and rain intensity—CN models the split to groundwater .

Question 60

Why is the hydrologic cycle complex?

Answer 60

It’s chaotic—no start, no end—spanning transportation, storage, and state changes across endless paths and timescales.

Question 61

What is transportation in the cycle?

Answer 61

Water moving—rain falling, rivers rushing, groundwater creeping.

Question 62

What is storage in the cycle?

Answer 62

Water parking—soil, aquifers, lakes, ice

Question 63

What are the state changes in the cycle?

Answer 63

Liquid to vapor (evaporation), vapor to liquid (rain), liquid to solid (snow), solid to liquid (melt).

Question 64

What is depression storage?

Answer 64

Surface traps—ponds, lakes, reservoirs—holding water.

Question 65

What is soil moisture storage?

Answer 65

Water in soil—pre-infiltration, post-rain—fuels transpiration, delays runoff.

Question 66

What is groundwater storage?

Answer 66

Aquifers and deep rock —slow, hidden reserves

Question 67

What keeps the cycle’s resources constant?

Answer 67

Earth’s water is fixed—sun drives, gravity enforces, no new water, just recycling.

Question 68

How do humans mess with the cycle?

Answer 68

Dams trap runoff, irrigation taps groundwater, paving kills infiltration, vapor suppression fights ET.

Question 69

What’s the role of the cycle in water power?

Answer 69

Dams harness stream flow—runoff’s the fuel.

Question 70

What is the difference between drainage area, drainage basin, watershed and catchment area

Answer 70

They are all the same, different names given to the same concept, - land area draining to a specific point or land surface that collects and funnels water to a specific point, like stream or lake.