Hydrology

Question 1

What is the molecular structure of water?

Answer 1

Water molecules are asymmetrical and bent at a 105° angle

Water consists of covalent bonds within the molecule and hydrogen bonds connecting different molecules.

Question 2

What makes water a universal solvent?

Answer 2

Water’s polarity due to oxygen’s electronegativity

Polar molecules dissolve in water through electrostatic interactions with water’s dipoles.

Question 3

What is surface tension in water caused by?

Answer 3

Cohesive hydrogen bonds at the surface

Surface tension allows water to form droplets and influences capillary action.

Question 4

What is the maximum density of water and at what temperature does it occur?

Answer 4

3.98°C

Density decreases with temperature.

Question 5

What is the high specific heat capacity of water at 0°C?

Answer 5

4216 J·kg⁻¹·K⁻¹

This high specific heat capacity is important for thermal regulation in climate systems.

Question 6

What is the latent heat of fusion for water?

Answer 6

334 J·g⁻¹

The latent heat of vaporization is 2500 J·g⁻¹, making evaporation energy-intensive.

Question 7

What influences river channel initiation?

Answer 7

Past topography, tectonics, and climate

These factors shape current drainage systems.

Question 8

What is the shear stress equation used in river channel formation?

Answer 8

τ = γ·d·sin(θ)

τ = shear stress, γ = weight density, d = depth, θ = slope.

Question 9

What is the vadose zone?

Answer 9

Unsaturated zone

The phreatic zone is the saturated zone.

Question 10

What are the types of overland flow?

Answer 10

• Infiltration Excess Overland Flow (IOF / Hortonian Flow)
• Saturation Excess Overland Flow (SOF)

IOF occurs when rainfall rate exceeds infiltration capacity; SOF occurs on saturated ground.

Question 11

What are the components of river flow sources?

Answer 11

• Throughflow
• Overland flow
• Precipitation
• Groundwater discharge

Response varies with soil characteristics, topography, catchment size, and drainage density.

Question 12

What does a hydrograph show?

Answer 12

Stream discharge over time

It is used to infer lag time, flow pathways, and landscape storage and movement.

Question 13

What are the main components of soil?

Answer 13

• Inorganic particles
• Organic particles
• Air

Soil texture determines porosity, field capacity, and wilting point.

Question 14

What drives infiltration in soils?

Answer 14

Capillary and gravitational forces

Infiltration starts fast and slows to a steady rate based on soil characteristics.

Question 15

What is Darcy’s Law?

Answer 15

Governs groundwater flow dynamics

It relates hydraulic head to flow rate and permeability.

Question 16

What defines a confined aquifer?

Answer 16

An aquifer between impermeable layers

Unconfined aquifers are open to the surface, while perched aquifers sit above impermeable layers.

Question 17

What is the water balance equation?

Answer 17

D = R + G; S = soil moisture, groundwater, snow/ice

It helps in water resource planning.

Question 18

What is baseflow?

Answer 18

Groundwater-sustained, slow, old water

Stormflow is fast and dominated by surface or macropore flow.

Question 19

What influences hydrograph shape?

Answer 19

• Area
• Slope
• Geology (permeability)

External factors include rainfall intensity and land use.

Question 20

What does the continuity equation calculate?

Answer 20

Discharge (Q) = flow volume per time (cumecs)

Discharge can be calculated using the area and velocity of flow.

Question 21

Fill in the blank: Water’s unique physical and chemical properties make it key in _______ and climatic systems.

Answer 21

[geomorphic]

Question 22

True or False: Saturated soils lead to increased slope stability.

Answer 22

False

Fully saturated conditions increase slope instability.