Hydrosphere Flashcards
What percentages of water do Industry, Domestic and Agriculture use?
Industry - 22%
Domestic - 8%
Agriculture - 70%
Why can demand for water increase?
- Population increase
- Increased affluence means more people use more water for more things
- Increased irrigation
- Industrialisation
What is residence time? How do you calculate it?
How long on average water stays in a particular form within the hydrological cycle. Volume of Water / Transfer Rate
How does Deforestation have an impact on the Hydrological Cycle?
Vegetation intercepts rainfall before it reaches the ground and release water from the soil via transpiration, losing trees would cause increased infiltration
How does Agriculture have an impact on the Hydrological Cycle?
Soil can be compacted by farm machinery or livestock reducing infiltration, crop irrigation increases evaporation rates and loss of soil biota can reduce infiltration and reduces water retention
How does Urban Development have an impact on the Hydrological Cycle?
Urban areas have impermeable surfaces that reduce infiltration and increase runoff, which can cause flooding downstream
How does Global Climate Change have an impact on the Hydrological Cycle?
Higher temperatures affect the rate of melting, evaporation and condensation and wind patterns.
What 3 things do we typically abstract water from?
Rivers, reservoirs and aquifers
What environmental effects can reservoirs have?
- Flooding of the area destroys old habitats but makes a new one
- Can act as wildlife barriers preventing migration or recolonisation
- reduces flooding risk down river
- reduces low-tide time in rivers
- sediments settle in the dam and are not carried downstream
- Warmer winter water, colder summer water
What factors affect reservoir site selection
- Topography
- Geology (impermeable rock)
- Water Supply
- Pollution Risk
- Sedimentation
- Existing land-use
What happened to the rivers and main body of the Aral sea?
Aral sea was the fourth largest lake in the world until water was diverted in 1960s to irrigate crops, resulting in the lake areas being reduced by 90% and being filled with waste, fertilisers and pesticides
What happened in the Tibetan Plateau and its rivers
Tibet was incorporated into China in 1950 and the water flowing from its plateau that feeds most rivers in Asia was subject to increasing population and industry, leading to over-exploitation and it is only made worse by climate change, reducing or removing a lot of Asian rivers
What are the 3 key features of an aquifer? Define each of them
- Porosity: The measure of the proportion of a rock that is free space and can therefore hold water.
- Permeability: How easily water can flow through a rock.
- Layout: Bottom of the aquifer must be low permeability while at least some of above has to be permeable, the actual aquifer must be porous rock
What is Aquifer Recharge? How does it work?
Aquifer Recharge is the process that keeps aquifers in equilibrium usually in the form of infiltrating precipitation. Some aquifers were only recharged in the last ice age 10-20,000 years ago
What are potential impacts of over-exploiting aquifers?
- Reduction in river lakes and marshes fed by aquifer
- higher water requirement plants may die
- salt water incursion may occur
- It may cause subsidence where the spaces in porous rock is compacted by above material
How can we monitor aquifer depletion?
- Checking water levels in wells or bore holes
- GRACE (Gravity Recovery And Climate Experiment) satellites can detect the change in mass caused by aquifers
What new methods of exploitation of water are there?
- Rainwater collection
- River water collection
- Estuary Barrages
- Sea Water
What is the issue with River Water and when does it arise?
Pollution from upsteam communities arises when said communities grow large enough that waste does not have time to break down before reaching the next community
How does artificial recharge of aquifers work?
Surplus water from high-rainfall periods can be pumped into aquifers directly or diverted to a place where it infiltrates easily
What are inter-basin transfers?
The transferal of water from an area with surplus to an area with a shortage through canals or pipes
How can afforestation help sustainable water management?
Trees reduce soil erosion and rainwater flow into rivers, reducing flooding and sedimentation after strong rainfall
What are common water conservation methods?
- Low volume water use appliances
- Low volume irrigation
- Recycling grey water (used but still clean enough)
- Control of acid mine drainage
- Sewage treatment
- buffer strips next to rivers to reduce fertiliser runoff
What is the sedimentation step of water treatment?
Water is allowed to remain static to let suspended solids settle
What is the Screen step of water treatment?
Metals grills or meshes filter out vegetation and litter
What is the Aeration step of water treatment?
Bubbles of air are used to ensure a high dissolved oxygen content, this also removes some dissolved metals
What is the Flocculation step of water treatment?
Clay particles, not removed earlier due to electrostatic repelling, are neutralised by flocculants like aluminium sulphate and allowed to settle
What is the Filtration step of water treatment?
Plant filters can be used to remove suspended solids or bacteria
What is the Activated Carbon Filter step of water treatment?
Particles of activated carbon are used to remove organic chemicals
What is the Sterilisation step of water treatment?
The addition of chlorine, ozone or UV light to kill pathogens and sterilise water
What is the pH Control step of water treatment?
Crushed lime is used to adjust pH
What is the Fluoridation step of water treatment?
Fluorides are added to water to improve drinker’s dental health
What is the Ion Exchange step of water treatment?
Toxic ions such as lead are adsorbed onto polymer beads to remove them
