4.1 water systems

What is the hyrdological cycle?

the continuous, solar-powered movement of water across the Earth, atmosphere, and land

what is the hyrdosphere?

includes all of Earths water, such as oceans, rivers, lakes and atmospheric moisture

how much of the earths water is ‘drinkable’?

Only about 2.5% of the Earth's total water is freshwater, and less than 1% of that is easily accessible for human consumption.

describe the hydrological cycle?

• The Sun's heat causes waterto evaporate from oceans, lakes, and rivers

• Water vapour cools and condenses into clouds, releasing heat

• Gravity pulls condensed water back to Earth via the process of precipitation (rain,

• snow, sleet, or hail).

• Gravity causes waterto flow over land into rivers and streams (runoff) and drain

• through soil

• Rivers flow downhill due to gravity, moving waterfrom inland back to the oceans

What are features of the hydrological cycle?

• closed system

• there are stores and flows

• processes in which water is constantly recycled through the system

what are the main stores in the hyrdological cycle?

• oceans

• glaciers and ice caps

• groundwater and aquifers

• surface freshwater (rivers and lakes)

• atmosphere

what are the main flows in the hyrdological cycle?

Transformations: processes where the state orform of water changes

Transfers: movements of waterfrom one location to another without changing state

Name all transformations in the hydrological cycle (7)

1. evaporation

2. transpiration

3. evapotranspiration

4. sublimation

5. condensation

6. melting

7. freezing

Name all transfers in the hydrological cycle (7)

1. advection

2. percipitation

3. surface run off

4. infiltration

5. percolation

6. streamflow

7. groundwater flow

What impact do humans have on the hydrological cycle?

they alter the natural processes of surface run-off and infiltration

What are the main human activities? (3)

1. agriculture

2. deforestation

3. urbanisarion

what is agriculture and irrigation what do they do?

irrigation= process of artifically supplying water crops —>modifying the water distribution and availability in a region

what can irrigation lead to? (2)

Artificially high evapotranspiration rates this is because more water is supplied to plants than would occur naturally

• This results in increased atmospheric moisture levels

• This can lead to localised increases in precipitation downwind ofirrigated areas, altering rainfall patterns in the region

increased surface run-off

• Water is applied fasterthan the soil can absorb it

• This causes waterto flow overthe soil surface, carrying sediments,fertilisers, and pesticides

• This leads to water pollution and nutrient imbalances

What is deforestation what does it do?

Deforestation refers to the clearing or removal offorests- this is primarily for agriculture, logging or urban development purposes (plants important = natural sponges and help recharge groundwater and maintain stream flows)

impacts of deforestation? (3)

• surface run-off increases —> more water reaches ground surface due to no canopy and vegetation

• reduces ecvapotranpiration

• increased erosion, reduced groundwater recharge

what is urbanisation what does it do?

Urbanisation involves the transformation of natural landscapes into urban areas with buildings, roads and infrastructure. Replacing permeable surfaces (such as soil and vegetation) with impermeable surfaces (concrete, asphalt)

impacts of urbanisation?

• prevent infiltration and reduced groundwater recharge—> increased flooding

• drainage systems—> overload natural water bodies and cause downstream flooding

• experinece higher temperatures —. increased evaporation rates and alter local percipitation patterns

what is steady state of water bodies?

involves analysing the balance between inputs and outputs. This balance ensures thatthe water level remains constant over time

What are flow diagrams?

visually representthe water inputs and outputs for a water body

examples of inputs in flow diagram?

Precipitation: rain, snow, or otherforms of waterfalling directly into the water body

Surface run-off: water flowing overthe land into the water body

GroundwaterInflow: water moving into the water body from underground sources

examples of outputs?

Evaporation: waterturning into vapour and leaving the water body

River outflow: water leaving the water body through rivers or streams

Groundwater outflow: water moving out ofthe water body into underground aquifers

Agricultural extraction: waterthatis extracted for irrigation