Water and its management Flashcards
Describe the global water distribution
- 97% of the water is saline ( inconsumable )
- 2/3rd of the freshwater we can consume is locked in glaciers
- Rest stored as groundwater (water in the soil or water held in pores of rocks)
- Surface freshwater is barely 1%
Describe the water cycle
- The sun heats the water in rivers, lakes, etc, and it evaporates into water vapor + transpiration from plants
- This moist water vapor rises because its less dense and forms into clouds through condensation
- It then precipitates and intercepts for human survival or freezes into glaciers and ice caps
Most of the water however runs off the surface into rivers as groundwater flow or infiltrates the ground through percolation which is stored in aquifers
Define percolation
The downward movement of water from soil to rock
Define infiltration
The downward moment of water through the soil and into the rock layer below
Define aquifer
A layer of porous and permeable rock that stores underground water
Define groundwater flow
The movement of water through rocks
How is water extracted from aquifers?
Through an artesian well-
A pipe is drilled from the surface to the aquifer.
Natural pressure means water will flow up on its own without the need for external pumping- This is the case when there is an impermeable and non-porous rock layer such as clay under and below the aquifer (flowing artesian well)
Effects of groundwater depletion
- Wells dry up
- Larger pumps are required (more energy +costs) since the water depth increases
- Land collapse
- Saline contamination
What is the crisis faced with both sources of freshwater?
Groundwater depletion- This occurs when water is being pumped out at higher rates than the aquifer is being replenished by the surface runoff and percolation of rainwater.
Surface water depletion- When the dams/ reservoirs/ lakes are being used faster than the tributary streams, rain etc, is replenishing it
Describe desalination plants
They involve removing dissolved salt from seawater and brackish (slightly salty) water from places such as river estuaries as well as treating wastewater (sewerage) to make it reusable for drinking.
Why don’t all countries invest in desalination plants?
It’s incredibly expensive and highly unaffordable for LEDCS who require it the most. This is because there are high costs of production, the process is energy intensive and it requires building large processing plants
How can you tell a countries economic situation from their water consumption?
LEDCS tend to have a high percentage of consumption in the agriculture sector (MEDCS agriculture will be intensive and water efficient)
MEDCS has the highest industrial and domestic (wells vs washing machines)
Difference between physical and economic water scarcity
Physical- All available reserves of water have been exploited
Economic- When there is insufficient water despite adequate reserves available due to a shortage in capital, income to exploit it
Difference between potable and non potable water
Potable is water that has been treated to ensure it’s free from external contaminants and harmful bacteria, unlike non-potable water which is extracted directly from wells, rivers, and lakes most likely contaminated by feces causing chronic diarrhea, and bacterial diseases like typhoid or viral infections like hepatitis A.
Difference between + Example-
- waterborne
- water bred
- water related
- Waterborne:
A disease caused by pathogenic microorganisms that are transmitted in contaminated freshwater - Water bred: Malaria
When the parasite breeds in water - Water related
Define dam
A barrier constructed across a river in order to control the flow of water leading to the creation of an artificial body of water, known as a reservoir, upstream of the dam
Uses of dams
- Collects water to irrigate adjacent crops
- Holds back water which is then released under pressure to turn turbines and generate electricity (hydroelectric power)
- Gather and distribute water for domestic and industrial use
- Improves navigation along rivers and canals by ships and barges carrying cargo
- Protects communities from flooding by regulating river flow and water discharge
What factors must be taken into consideration before developing a dam in an area?
- Stability of land (should be able to sustain high hydraulic pressure)
- Narrowing of a river within a deep valley or cannon
- Close to where consumption will occur
- Sufficient rainfall
- With no resident population (would have to force them to relocate)
- Local materials
How do multipurpose dams contribute to economic development?
- They provide renewable energy
- They regulate water levels
- They distribute fresh drinking water
- They feed irrigation systems which boost food production
Social and environmental costs of building multipurpose dams
- Resettlement of people
- Large-scale habitat destruction:
- construction harms fish migration patterns
- reduction of downstream water levels
- blocks the free flow of nutrients
- water temperature increasing
- Harmful for people who rely on fisheries for their livelihood
- Fertilisers brought through run-off are trapped in the water leading to eutrophication and algal blooms which depletes oxygen levels
- Poor maintenance –> breeding grounds for mosquitoes
- Vegetation below the reservoir decaying releases methane
Define eutrophication
The pollution of water bodies by nutrients leading to the rapid growth or blooms of algae and deoxygenation
Impacts of domestic waste
Sewage waste, waste water, detergents dissolved water
- Pathogens in water contaminated by feces can cause chronic diahrea, typhoid
- Detergents damage fish gils and destroys their eternal mucus layer
Impacts of industrial processes
- Lead and mercury from the manufacturing of goods
- Acid rain (SO2+ NO2)
- increases acidity from 5.5- 2/3 (fish eggs can’t hatch)
- damages the waxy layer on leaves which prevents them from absorbing nutrients
- leaches out aluminum and carries it into rivers and lakes
Impacts of agricultural practices
- Drainage of animal waste, disposal of sheep dip, runoff of fertilizers
- Crops can absorb small quantities of mercury, lead, etc which is harmful to humans
- Soil erosion –> sedimentation –> stagnation + deoxygenisation
- Artificial growth hormones injected into animals are excreted which causes eutrophication
Define bioaccumaltaion
Process of how water pollutants increase in concentration through all the trophic levels of the food chain
Define sanitisation
Provision of clean drinking water and adequate sewage and water treatment services for waste domestic water
How do LEDCS improve their sanitation
They have to develop less expensive and sustainable sanitation systems that rely on local resources and expertise rather than advanced technology and high capital cost
- Domestic toilet design
- Pit emptying
- Sludge treatment
- Ways to reuse water
Explain the spread of Malaria
Malaria is water-bred as the female Anopheles mosquito that spreads it breeds below the surface of warm and stagnant water bodies. The plasmodium parasite is transmitted through the mosquito that mainly bites during the night
- The mosquito bites to suck blood and inserts a liquid to prevent blood clotting, to get nutrients to lay eggs
- The parasite is contained in this liquid and infects the individual (If the person is already affected, the mosquito just sucks out the parasites from their blood)
- Once in the bloodstream, the parasite travels to the liver and develops the infection which then reenters the bloodstream invading the red blood cells where the parasite grows and multiplies
- The infected blood cells burst every couple of hours releasing more- this causes the interval chills, sweating, and fever
If not treated, this can turn to severe anemia and cerebral malaria
Ways to prevent malaria-
- Antimalarial drugs
- Insecticide-treated mosquito nets
- Insecticide spray
Why is it hard to fight malaria?
- Infected victims often do not show symptoms
- Can’t afford to invest in measures that collect and analyze blood samples
- The mosquito and parasite have shown to have developed resistance against the drugs and insecticides
- Eradication requires huge amounts of unavailable money
- Developing a vaccine is extremely difficult
- Mating the genetically engineered gene of the mosquito which is now highly resistant to the paraiste
- Becoming more mobile–> more transportation of the parasite
Cholera: Describe Symptoms People at risk Preventation
A waterborne disease caused by consuming food/water infected by Vibrio cholera.
Symptoms- Stomach cramps, vomiting, and diarrhea –> dehydration
Spreads through drinking water that has been contaminated with the feces of an infected person
People at risk- Those with low immunity, low sanitation areas, refugee camps with quickly contaminated water
Can be stopped by boiling water, disinfecting through chlorination, cholera vaccination, access to potable water, oral rehydration solution (salt+ glucose in purified water)
Define improved sanitation
A system that effectively separates human waste from drinking water
Define Surface run-off
precipitation that flows over the ground surface, eventually finding its way into streams and rivers
Define Interception
precipitation that doesn’t reach the Earth’s surface due to being obstructed by trees and plants
Physical factors for the location of the dam
High precipitation to provide sufficient water;
Low temperature to prevent evaporation;
Built on strong impermeable rock so water doesn’t drain and has a good foundation;
Built high up in order to have good potential for hydro-electric power;
Rivers and lakes nearby to provide water;
Away from developed areas to reduce the risk of pollution in reservoirs;
Difference between water-borne and water-bred
Water-bred disease: the carrier breeds in water and spreads the disease by biting its victims.
Example: malaria.
Water-borne disease: spread by consuming contaminated water due to poor sanitation and untreated sewage, or by washing food, pots and pans, or hands and face in dirty water.
Examples: cholera
