2. The water cycle

Question 1

define interception

Answer 1

rainwater which hits the surface of something

Question 2

define stemflow

Answer 2

water flowing out of the plant

Question 3

define infiltration

Answer 3

water enters the pores of the soil

Question 4

water table

Answer 4

the depth at which the rock becomes saturated

Question 5

define percolation

Answer 5

the movement of water through soil, soil -> ground water

Question 6

why does water flow horisontally

Answer 6

in order for water to flow horizontally the vertical flow must be impeded, this is done by:
1. impermeable surface - no spaces for water to infiltrate so surface runoff occurs
2. saturated ground - all spaces are full of water and it cannot take in anymore - saturation excess overland flow
3. porosity/infiltration rate - if the rate of precipitation is greater than the rate of infiltration - infiltration excess overland flow

Question 7

what factors affect the rate of evaporation

Answer 7

1. insulation/solar radiation - radiation and the resulting heat causes evaporation of water
2. availability of water - is the water liquid or solid, is the water exposed or absorbed (i.e. soil)
3. temperature of air - warmer air can hold more moisture
4. humidity - the closer the air is to saturation point the slower the rate of evaporation

Question 8

what causes condensation (and thus precipitation)

Answer 8

for condensation to take place water vapour must have something to condense onto e.g.dust or pollution (condensation nuclei)
warm, moist air passes over a cool surface causing it to condense
condensation is the direct cause of precipitation

Question 9

what causes orographic/relief rainfall

Answer 9

formed when air is forced to cool when it rises over relief features in the landscape such as hills or mountains. As it rises it cools, condenses and forms rain

Question 10

what is continentality

Answer 10

A location’s proximity to the sea affects its temperature and how often it rains
during summer, the sea heats up less quickly than the land. During winter, the opposite happens, and the sea retains heat from the sun longer than the land.

Question 11

define sublimation

Answer 11

strong sunlight and dry winds (low relative humidity) hits a snowpack and frozen water goes directly from solid to gas

Question 12

define deposition

Answer 12

moist air touches a cold surface and instantly freezes (hoar frost)

Question 13

why might the magnitude of water cycle stores change over time

Answer 13

hourly/daily -
during the day rain clouds can build up, forecasting rain
seasonally -
snows more in winter - colder avg temps, rainy seasons/monsoons
over longer periods - ice ages

Question 14

how has the hydrosphere changed with climate change

Answer 14

95.6% of the earth’s water is stored in the oceans
the burning of fossil fuels has caused bodies of water to become more acidic - Carbon dioxide reacts with sea water to produce carbonic acid. The resulting increase in acidity (measured by lower pH values) changes the balance of minerals in the water
as ice sheets decline water is released into the oceans

Question 15

how has the cryosphere changed with climate change

Answer 15

almost all freshwater is locked up in glaciers (68.7%)
the amount of water held in ice caps fluctuates due to the varying temps
climate change decreases the volume of water in the cryosphere
rate of melting in the andean glaciers is threatening many cities in peru

Question 16

how has the lithosphere changed with climate change

Answer 16

30% of earths freshwater is stored in the ground
climate change has changed the distribution of water in the lithosphere - desertification in reducing soil moisture
the changing weather patterns like high winds can increase erosion
drought, dry soils as well as flooded soils all affect food production

Question 17

how has the atmosphere changed with climate change

Answer 17

increased temps lead to warmer air, more evaporation
rising warm air holds water vapour which condenses to form clouds - changed weather patterns, more storms
water vapour is a greenhouse gas and furthers climate change

Question 18

describe the factors and flows that affect the drainage basin

Answer 18

vegetation and land use -high vegetation leads to high rates of interception, root uptake and evapotranspiration (reduces river discharge)
in low temps there is less growth so there is less root uptake and less interception
rainfall - long duration leads to saturation excess overland flow
shape of land - steep land means gravity will pull water down faster
climate - weeks of rainfall rises the water table meaning the basin can become saturated faster
high temps increase evapotranspiration which reduces drainage
low temps freeze water so there will be no runoff
soil type and depth - sandy soils have a faster rate, clay soils allow very little throughflow which results in less surface runoff
bedrock - permeable rock (chalk and sandstone) allows water to percolate through
impermeable rock (granite) stops percolation resulting in high surface runoff, soils become saturated
conditions in drainage basin - if soil is frozen it is impermeable, baked ground (so hot and dry) is also impermeable
size and shape of river basin - in a large basin water takes a long time to travel to the channel
in a circular basin all points are equivalent so there will be a shorter lag time
elongated basins have longer lag times and lower peak discharge

Question 19

define recharge

Answer 19

A time when water is added to soil moisture storage the recharge create a cousin facilitation exceeds potential evapotranspiration but the soil has yet to reach its field capacity

Question 20

define surplus

Answer 20

Occurs when precipitation exceeds potential about the transpiration and the soil has reached its field capacity
any additional water applied to the soil runs off if this water runs off into nearby streams and rivers it could cause flooding
the intensity and duration of surface can be used to predict potential flooding

Question 21

define utilisation

Answer 21

The utilisation season is a time and water is withdrawn from soil moisture storage
the utilisation period occurs and potentially backward transpiration exceed the precipitation but soil storage has yet to reach 0 (dry soil)

Question 22

define deficit

Answer 22

The deficit season occurs when potential evapotranspiration exceeds precipitation and soil storage has reached zero

Question 23

what is a river regime

Answer 23

The variability in a river discharge throughout the course of a year in response to precipitation temperature in evapotranspiration and drainage basin characteristics

Question 24

what are ephemeral streams

Answer 24

Ephemeral streams are temporary streams
found in arid or semi arid environments like Arizona
high evapotranspiration, soil deficit and low precipitation
streams appear following intense precipitation - precipitation exceeds infiltration rate but disappear very quickly

Question 25

what are intermittent streams

Answer 25

intermittent streams are seasonal streams
they occur in strong seasonal climates like a monsoon India
in the dry season they have high ET, soil moisture deficit and dry channels
in the wet season there’s a soil moisture recharge/surplus and seasonal streams

Question 26

what are perennial streams

Answer 26

Perennial streams are permanent streams they are maintained by base flow for example in the UK

Question 27

what happens with increased and decreased interception

Answer 27

Increased interception - leads to a decrease in peak discharge, lag time will increase, the graph will be more subdued
decreased interception - lower peak discharge, shorter lag time, flashy graph

Question 28

what happens with increased and decreased precipitation

Answer 28

Increased precipitation - leads to an increased peak discharge, lag time decreases = saturation excess overland flow and infiltration excess overland flow lower peak discharge and a longer lead time because the ground is not saturated infiltration is higher and exception is back to ground after drought where there is less lag time

Question 29

what happens with increased infiltration

Answer 29

Increased infiltration - lower peak discharge, slower lag time because through flow is slower than surface run-off
decreased infiltration - leads to larger discharge because less water will be able to flow through the soil this makes the hydrograph more flashy

Question 30

which water cycle processes affect the carbon cycle