Water and water resources

Question 1

What are the main reservoirs in the hydrological cycle?

Answer 1

Oceans (93%), Terrestrial water (5%), Polar ice (2%), Atmosphere (0.001%).

Question 2

What is residence time?

Answer 2

The average time water stays in a reservoir.

Question 3

How long does water stay in the atmosphere on average?

Answer 3

<10 days.

Question 4

What is evapotranspiration?

Answer 4

Combined water loss from evaporation and plant transpiration.

Question 5

What affects evapotranspiration?

Answer 5

Net radiation, soil heat flux, air density, specific heat, vapour pressure, and surface/aerodynamic resistances.

Question 6

What is the Charney Hypothesis?

Answer 6

Suggests vegetation reduces albedo, enhancing monsoonal rainfall through a feedback loop.

Question 7

What is actual evapotranspiration?

Answer 7

Evapotranspiration that occurs based on actual water availability.

Question 8

What is potential evapotranspiration?

Answer 8

Evapotranspiration that would occur with unlimited water.

Question 9

How is atmospheric water measured?

Answer 9

Using satellite reflectance and repeat surveys (e.g. MODIS).

Question 10

What process recycles moisture in the Amazon?

Answer 10

Rainforest evapotranspiration, which contributes 50-60% of precipitation.

Question 11

What are the three zones in a hillslope?

Answer 11

Root zone, Unsaturated zone, Saturated zone.

Question 12

What is infiltration-excess overland flow?

Answer 12

Overland flow when rainfall intensity exceeds infiltration rate.

Question 13

Who proposed the infiltration-excess model?

Answer 13

Robert Horton in 1933.

Question 14

What is saturation overland flow?

Answer 14

Overland flow caused by a rising water table, even if rainfall intensity is low.

Question 15

What law governs flow in saturated soil?

Answer 15

Darcy’s Law.

Question 16

What is Ks in Darcy’s Law?

Answer 16

Saturated hydraulic conductivity.

Question 17

What affects Ks?

Answer 17

Soil type and texture.

Question 18

What law applies in unsaturated soil?

Answer 18

Richards equation.

Question 19

What is a Variable Source Area?

Answer 19

Area contributing to runoff varies in space and time depending on saturation.

Question 20

What were the Plynlimon experiments?

Answer 20

Paired catchment studies comparing forested and grass catchments.

Question 21

What is macropore flow?

Answer 21

Rapid water movement through large pores from roots or animals.

Question 22

What causes pipeflow?

Answer 22

Natural pipes in soils or artificial drainage.

Question 23

What are the two key flood processes?

Answer 23

Flow accumulation and flow attenuation.

Question 24

What is Manning’s n?

Answer 24

Empirical value representing surface roughness in flow calculations.

Question 25

What increases flow attenuation?

Answer 25

Floodplain storage, vegetation roughness, and slower water velocities.

Question 26

What is a disadvantage of dredging?

Answer 26

It can increase downstream flood risk.

Question 27

What causes increased urban flood risk?

Answer 27

Impermeable surfaces and poor drainage.

Question 28

What is social vulnerability to flooding?

Answer 28

Risk exposure based on demographics, infrastructure, and insurance.

Question 29

What determines flood risk?

Answer 29

Flood hazard × exposure × vulnerability.

Question 30

What are the pros of floodplain use?

Answer 30

Storage for floodwaters, reduced peak flow downstream.

Question 31

What was the Messinian Salinity Crisis?

Answer 31

A period when the Mediterranean was cut off and evaporated significantly.

Question 32

What is the Zanclean Megaflood?

Answer 32

Refilling of the Mediterranean from the Atlantic around 5.3 Ma.

Question 33

What are badlands?

Answer 33

Eroded landscapes of soft sediment often formed in Mediterranean conditions.

Question 34

What characterizes Mediterranean climate?

Answer 34

Wet winters and hot, dry summers.

Question 35

How do plants adapt to water stress?

Answer 35

Waxy leaves, small leaves, open canopies, leaf shedding.

Question 36

How does vegetation affect runoff?

Answer 36

Increases infiltration and reduces sediment loss.

Question 37

What is a feedback from vegetation to climate?

Answer 37

More vegetation → lower albedo → more rainfall.

Question 38

What is aeolian input?

Answer 38

Dust transported by wind, contributing to soil formation.

Question 39

What are effects of fire on hydrology?

Answer 39

Increased runoff, hydrophobic soils, reduced interception.

Question 40

What increases fire risk in Mediterranean areas?

Answer 40

Land abandonment and dry, hot conditions.

Question 41

What is meteorological drought?

Answer 41

Period of below-average precipitation.

Question 42

What is hydrological drought?

Answer 42

Low river, lake, and groundwater levels.

Question 43

What is agricultural drought?

Answer 43

Soil moisture too low for crops.

Question 44

What is socio-economic drought?

Answer 44

Water supply fails to meet societal needs.

Question 45

What does SPI stand for?

Answer 45

Standardized Precipitation Index.

Question 46

What does PDSI stand for?

Answer 46

Palmer Drought Severity Index.

Question 47

Why is winter rainfall crucial in the UK?

Answer 47

It recharges groundwater.

Question 48

What are plant responses to drought?

Answer 48

C3, C4, and CAM photosynthesis strategies.

Question 49

What is xeriscaping?

Answer 49

Landscaping to reduce water use.

Question 50

What happened to Owens Lake?

Answer 50

Dried due to LA aqueduct diversion, causing dust storms.

Question 51

What is advection?

Answer 51

Transport of material by bulk flow.

Question 52

What is diffusion?

Answer 52

Movement from high to low concentration without bulk flow.

Question 53

What landscape shape does diffusion produce?

Answer 53

Convex hillslopes.

Question 54

What shape results from advection?

Answer 54

Concave valleys.

Question 55

How does vegetation affect water flow?

Answer 55

It increases infiltration and alters soil moisture distribution.

Question 56

How does vegetation affect erosion?

Answer 56

It reduces splash erosion, binds soil, and increases roughness.

Question 57

What is tree throw?

Answer 57

Soil disturbance by uprooted trees.

Question 58

What is the effect of burrowing animals?

Answer 58

Increase infiltration and disturb soil.

Question 59

What is the role of faecal matter in hydrology?

Answer 59

Enhances soil aggregation and stability.

Question 60

What is equifinality?

Answer 60

Different processes producing similar landforms.

Question 61

What is latent heat of vaporization?

Answer 61

2.5 MJ/kg.

Question 62

What is the lapse rate?

Answer 62

Rate of temperature decrease with altitude.

Question 63

What causes runoff?

Answer 63

Rainfall intensity exceeding infiltration or saturated soils.

Question 64

How does slope affect runoff?

Answer 64

Steeper slopes increase runoff speed.

Question 65

What is baseflow?

Answer 65

Portion of streamflow sustained by groundwater.

Question 66

What is infiltration?

Answer 66

Process by which water enters the soil.

Question 67

What is percolation?

Answer 67

Downward movement of water through soil layers.

Question 68

How does land use affect flooding?

Answer 68

Urbanization increases runoff and reduces infiltration.

Question 69

Why is vegetation important for water regulation?

Answer 69

It intercepts rainfall and enhances soil retention.

Question 70

What is hydrophobic soil?

Answer 70

Soil that repels water after fire, reducing infiltration.