The hydrological cycle

Question 1

The hydrological cycle is…

Answer 1

continuous circulation of water between the atmosphere, lithosphere and biosphere.

Question 2

Interception is the precipitation…

Answer 2

that lands on trees and other vegetation.

Question 3

Infiltration-surface water…

Answer 3

soaks into the soil.

Question 4

Throughflow-water flows…

Answer 4

through soil.

Question 5

Percolation-water moves…

Answer 5

downwards through permeable rocks. In Chalk it is fast.

Question 6

Groundwater flow is very slow…

Answer 6

movement of water into the river.

Question 7

Hortonian overland flow is any…

Answer 7

surface runoff as a result of higher rainfall intensity than infiltration capacity.

Question 8

Saturated overland flow caused when…

Answer 8

the soil has reached its maximum soil moisture capacity and infiltration is 0.

Question 9

Condensation-water vapour…

Answer 9

cools down and clouds are formed.

Question 10

Evaporation-water heated by…

Answer 10

sun becomes water vapour(latent heat)

Question 11

Groundwater is water…

Answer 11

stored in porous rocks.

Question 12

The water table is…

Answer 12

the top of the saturated zone in permeable rock. It may rise or fall depending on inputs and outputs of the hydrological cycle.

Question 13

Drainage cycle is…

Answer 13

open as water can be transferred to other areas,

Question 14

Stem flow is any precipitation…

Answer 14

that has been intercepted by vegetation, then passes down the branches and stems of vegetation.

Question 15

How to calculate discharge?

Answer 15

• cross-sectional area and velocity are required
• discharge requires the multiplication of CSA and velocity
• recorded as cumecs-cubic meters per second

Question 16

Potential evapotranspiration is…

Answer 16

the water loss that would occur if there was an unlimited supply of water for vegetation. E.g. Egypt has annual precipitation less than 250mm, but potential EVP is 2000mm.

Question 17

Discharge is…

Answer 17

the movement of water in channels.

Question 18

Soil water or soil…

Answer 18

moisture is the subsurface water in the soil above the water table.

Question 19

Field capacity refers to…

Answer 19

amount of water held in the soil after excess water drains out.

Question 20

Soil moisture deficit is the degree to which…

Answer 20

soil moisture falls below field capacity.

Question 21

Soil moisture recharge occurs when…

Answer 21

precipitation exceeds potential evapotranspiration.

Question 22

Soil moisture surplus is the period when…

Answer 22

soil is saturated and water cannot enter, so flows over the surface.

Question 23

Soil moisture utilisation is the process by which…

Answer 23

water is drawn to the surface through capillary action.

Question 24

The amount of fresh water in groundwater stores is…

Answer 24

97%.

Question 25

Surface water stores:

Answer 25

• lakes
• small puddles following a storm
• wetlands, swamps
• snow, ice

Question 26

The phreatic zone is…

Answer 26

permanently saturated zone within solid rocks and sediment.

Question 27

Aquifers are rocks that…

Answer 27

contain significant quantities of water, provide a reservoir. Rocks such as limestone or sandstone.

Question 28

Recharge of groundwater:

Answer 28

• infiltration
• seepage(through banks and bed of rivers, lakes)
• artificial recharge from irrigation

Question 29

Losses of groundwater:

Answer 29

• evapotranspiration
• natural discharge(spring)
• artifical abstraction (Saudi Arabia resrve decreased by 42% since 1985)

Question 30

Aeration zone is between…

Answer 30

water table and the surface. Also called the unsaturated zone.

Question 31

Aquitard is a band of…

Answer 31

rock with low permeability.