The hydrosphere (The physical environment)

What is the hydrosphere

The earths water in solid liquid and gas forms including lakes, snow, water vapour

Chemical formula of water

H20, two hydrogen atoms and an oxygen atom

Hydrogen bonds

Weak bonds individually but strong in great numbers joining water molecules together

Dynamic equilibrium

Processes in a state of balance cancelling eachother out

Evaporation

Water turning from liquid into gas

Condensation

Water turning from gas to liquid

Precipitation

Any form of water falling from the sky eg rain snow sleet

Transpiration

Water evaporating from the leaves KF plants to become water vapour in the atmosphere essential for plant uptake

Why is water essential for life on earth

Waters property KF dissolving all charged compounds facilite faster chemical reactions in solution and can transport nutrients in blood and plants

What is high specific heat capacity and why is it important for living organisms

Means It takes a large amount of energy to change the temp of water by 1 degree which creates stable habitats for living organisms

Is solid or liquid water more dense

Ice is less dense than its liquid form allowing it to float and as an insulator for ponds/lakes

Reservoirs of water

A store of water, the largest being the oceans followed by ice and groundwater

Residence time

The average time water remains in a reservoir important for sustainable water management

Which energy source drives the processes in the hydrological cycle

Solar energy causes water to evaporate for eg

What energy form would water be stored in clouds as water vapour

Gravitational potential energy

Inputs, outputs, throughflow

Catagorisation processes in the hydrological cycle

Inputs- precipitation, surface water inflow, condensation, groundwater inflow Outputs- evaporation, transpiration

Throughflow- surface runoff, interception, percolation

What impact does deforestation have on processes in the water cycle

Reduces transpiration, interception, increases surface runoff leading to water cycle disruption and droughts

How do agricultural practices impact processes in the water cycle

Compaction of soil, reduced infiltration, increased surface runoff, causes soil erosion

What is irrigation and how does it impact reservoirs in the water cycle

Large scale watering of crops, reduces water stored in reservoirs, increases water vapour in downwind areas

How does urban development impact processes in the water cycle

Impermeable surfaces reduce infiltration and increase surface runoff leading to flooding

How does global warming impact processes in the water cycle

Rising temps alter water availability increasing snow/ice melt and increase evaporation whilst decreasing precipitation

States of water in order from most hydrogen bonds to least

Solid, liquid, gas

Residence time calculation

Volume/mean transfer rate

Global water demand

The total amount of water needed by all industries and individuals worldwide

How does population increase global water demand

Birth rate could be higher than death rate, immigration

How does increased affluence increase global water demand

Increased affluence means increase per capita and piped water becomes more accessible so it can be used in appliances eg dishwashers and washing machines

How does irrigation increase global demand for water

As commercial agriculture expands increased income allows money to be invested in irrigation schemes that water can be pumped from eg aquifers

How does industrialisation increase global water demand

Heavy industries such as the chemical, steel, paper making, use more water than lighter manufacturing industries

Per capita water use

The average amount of water consumed by an individual in a specific area often measured in liters per day

Water born diseases

Illness caused by microorganisms in contaminated water leading to health issues and potential epidemics eg cholera

How does water scarcity impact economies

Limited ability of water for manufacturing processes and electricity generation hinders economic development and infrastructure investment

Drip irrigation

A method of watering plants by applying water slowly and directly to the soil reducing water waste and promoting efficient growth

Human impacts to the hydrosphere

Deforestation- loss of trees causes changes in precipitation in downwind areas as more water infiltrates the ground/runoff into rivers

Agriculture- soil becomes compacted due to machinery/livestock trampling so water can infiltrate easily increasing runoff

Urban development- these areas have impermeable surfaces like concrete or tarmac reducing infiltration

Global climate change- higher temps affects rates of evaporation, melting, condensation, altering the type amount and location of precipitation

Aquifer

A layer of rock or sediment that holds and transmits water

Porous

Having small holes/air spaces that can hold water

Permeable

Allowing water to flow through easily due to interconnected air spaces

Impermeable

Not allowing water to pass through

Aquifer recharge

The natural process of rainwater percolating into the aquifer to replenish it

Confined aquifer

An aquifer under high pressure causing water to rise without pumping

Unconfined aquifer

An aquifer where water must be pumped to reach the surface due to lack of natural pressure

Artificial recharge

The process of pumping water into the aquifer to replenish supply

Water table

The level below the ground where soil and rocks are saturated with water

Saltwater incursion

The intrusion of salt water from the ocean into a freshwater aquifer as a result of aquifer depletion

Osmotic dehydration

The process of water leaving plant tissues when watered with saltwater

Subsidence

The sinking of the ground surface due to the depletion of the aquifer

GRACE satellites (aquifer)

Used to monitor changes in the earths gravitational field to detect aquifer depletion

Boreholes

Drilled holes used to measure the depth of the water table and obtain physical samples

Associated geological structures of aquifers

Rock below must be impermeable to prevent water escape and Rick universe must be permeable for recharge

Recharge of aquifers

Input and output must be at a dynamic equilibrium or if abstraction is greater then volume will decline

Overexploitation of aquifers

Changes in surface hydrology- overexploitation leads to lowered water table

Ecological impacts- plants with high water requirement will be outcompeted by others, aquatic animals will die, salt water incursion happenS

Examples of overexploited aquifers

North China Plain- largest agricultural in china with fertile soil but few rivers so ground water is used for irrigation, demand has cause 1m per year decline, low pressure irrigation pipes are used to reduce leaks large scale afforestation projects have been developed

Reservoir

Large body of water with a dam used for storing water for public use

Dam

A barrier built across a river to create a reservoir and control water flow

Topography

The shape and features of the land surface including natural and man made features eg valleys

Why would a reservoir be built somewhere with stable geology

Low risk of earthquakes if away from fault lines

Why does a reservoir bedrock need to be impermeable

Doesnt allow water to infiltrate into the ground and leave the reservoir

Catchment area

The area where rainfall flows into a river,lake or reservoir

Infrastructure

The physical and organisational structured and facilities needed for society or enterprise operation

Microclimates

Small areas with slightly different climate from the surrounding area

Salmon cannons

Devices used to transport their migration route without injuries

Trophies cascades

The ecological phenomenon triggered by the addition of removal of top predators involving reciprocal changes in predator and prey populations through a food chain

Ramsay sites

Protected wetland areas designated to be of international importance under the Ramsar convention

How will reservoir construction alter the surrounding environment

Habitat change- flooding destroys habitats but can create new wetlands or more value

Wildlife barriers- acting as barriers to migration such as salmon preventing recolonisation

River regime downstream- water can regulate the flow by holding it back during shortage and reducing risk of flooding downstream, reducing periods of low flow and important for egg laying

River case studies

Rivers in the Aral Sea- used to be 4th largest lake in the world due to the Syr Darya and Amu Darya rivers but due to irrigation schemes for cotton/rice crops the area was reduced by 90% and polluted by fertilisers, pesticides and industrial waste

River Nile- largest river in the world, goes through 10 countries, disagreements over water abstraction for irrigation and dam construction to regulate flow, provide electricity etc

Inter basin transfer

The transfer of water from surplus to shortage areas using canals and pipes to address regional water imbalances

River regulation reservoirs

Reservoirs created to regulate river flow and store surplus water this preventing flooding and ensuring a steady supply of water

Recharge reservoir

A structure on the ground above the aquifer that encourages water infiltration into aquifers helping to replenish underground water sources

What do recharge reservoirs do

Recharge aquifers

Xeriscaping

Planting xerophytes (plants that can survive in arid conditions) in public areas so they require less watering

Greg water use

Fairly clean water is reused from baths or showers for non drinking purposes reducing the demand on public water supply

Water infrastructure maintenance

Preventing leakage and promoting efficient water use through the maintenance of the supply systems as around 20% is lost

Rainwater collection

collection of rainwater for non drinkable uses reducing the demand on public water supply

Estuary barrages

Freshwater reservoirs with dams located where rivers meet the sea serving as a source of freshwater supply

Seawater desalination

Removing salt from seawater requires significant energy and is expensive only used when there’s an inadequate supply of freshwater

Water treatment steps

1- sedimentation: suspended solids need to settle

2- screens: metal grills/ meshes remove vegetation, litter, plastic

3- Aeration- air bubbles ensure a high dissolved oxygen content/remove toxic metals

4- Flocculation: neutralizó electrostatic charged on clay particles to allow them to settle

5- Filtration: Slow flow through sand/gravel removed any remaining suspended solids/bacteria

6- Activated carbon filters: used to remove organic chemicals eg pesticides

7- Sterilisation: addition of chlorine ozone or UV light kills pathogens

8- pH control: sterilisation with chlorine can make the water acidic so it’s ajustes by adding crushed lime

9- Fluoridation: fluorides added to improve dental health of consumers

10- Ion exchange: toxic ions eg lead mercury, arsenic can be removed using this

11- reverse osmosis: saline water filtered at very high pressure through a partially permeable membrane of very small polyamide tubes which is energy intensive

12- distillation- water boiled by heating and or reducing the pressure steam is produced then condensed then collected