Water Security 2 Flashcards
Describe what happened to the Aral Sea in the 1960’s
Soviet Union diverted the Anna Dairyer and the Sydronyia (two rivers which fed into the Aral Sea) for a mass irrigation project to grow cotton in the desert
By 2007, it had declined to 10% of its original size - now mostly desert
Give some effects of the shrinking Aral Sea
The region’s once prosperous fishing insustry has essentially been destroyed - unemployment + economic hardship
Retreat of the sea has caused local climate change - summers becoming hotter and drier and winters colder + longer
Decades of heavy irrigation has brought the water table to the surface - making drinking water and food to salty + polluted
Outline 3 strategies to increase water supply
Catchment and Storage
Diversion and Inter-basin transfer
Desalination
Explain Catchment and Storage as a strategy to increase water supply
LARGE SCALE
- Interrupting and storing the flow of water via dams and reservoir schemes
- Can be multi-purpose: HEP, tourism, fishing
SMALL SCALE
- Rainwater harvesting
Give some examples of Catchment and Storage
Three Georges Dam - largest in world
Lake Nasser Dam - Egypt
Small scale = Bangalore, India. Rainwater system compulsory in buildings over a certain size
Give pros and cons of Catchment and Storage
CONS
- Zero sum game. One group may benefit at the expense of another
- Changes river regime downstream - sedimentation over time reduces capacity
PROS
- Can be multi-purpose
- Relatively cheap, can lead to water self-sufficiency (Small scale)
Explain Diversion and Inter-Basin Transfer as a strategy to increase water supply
River diversion is used to transfer water form one river catchment to another when there is a surplus of water in one area, and too little in another
Water is drawn from rivers, reservoirs and aquifers, and pumped across the region, enabling localised droughts to be tackled quickly
Give anexample of Diversion and Inter-basin transfer
China intends to build the South-North Water Transfer project
This would divert 44.8 billion m3 of water per year from the Tonytbe River, to the Yellow River
Give some pros and cons of Diversion nd Inter-Basin Transfer
CONS
- Were plans to divert Western Water to S.E England, but abolished due to construction costs, ecological concerns and public resistance to move
- China’s project relocation is exacerbating social inequalities - making the North richer
PROS
- Helps drought affected regions quickly and effectively
Explain Desalination as a strategy to increase water supply (Two Ways)
REVERSE OSMOSIS
- Involves filtration of seawater at high pressures through a partially permeable membrane, using small polymeric tubes to convert it to potable water. Collects freshwater, and rejects very saline water which is pumped back to sea
DISTILIATION
- Water is boiled by heating under reduced pressure to save energy - The steam produced is condensed and collected separately whilst the salt is left in the boiler
Give some examples of Desalination plants
Generally developed in wealthy countries with water stress: Saudia Arabia, Oman, UAE
Thames Water’s Desalination plant at Brecon provides water for over 400,000 homes through reverse osmosis
Give a pro and con of Desalination
CONS
- Expensive and not considered sustainable because it is very energy intensive + a significant source of greenhouse emissions.
- Would still need to transfer it via Inter-Basin transfer to reach affected areas
PRO
- Provides a huge new supply of water
Give two agricultural ways of managing water demand
Irrigation scheduling: prevents farmers from over-irragating - linked to controls and subsidies for groundwater pumping
Mulching: covering soil with protective plastics to prevent water evaporation nd keep temperature constant
Give two industrial ways of managing water demand
Power industries replace traditional water cooling systems with air cooling ones
Water pressure reduction - reduce pressure in pipes, thereby reducing losses from leaks
Give two domestic ways of managing water demand
Wastewater reuse - reuse treated municipal and industrial water as municipal public and industrial cooling water
Shower-heads and taps - installation. of water-efficient shower-head and taps with aerators and pressure controls to keep water flow at desired levels
Explain Partial Root-Zone Drying as a strategy to manage water consumption
- One side of the plant given drip irrigated water, whilst the other side of the plant/root are deprived of water
- Makes plant think its in a drought - closing its stomata, reducing ater loss through transpiration
- However, because one side is still being irrigated there’s no water stress. Can cut water usage by 50% whilst maintaining/slightly increasing crop yields
Give 5 sustainability issues linked with water management
Virtual Water Trade
Water Conservation
Recycling water
Grey water
Groundwater management
Explain virtual water trade
Refers to the total requirement of water for a commodity/manafactured product that is subsequently exported
Producers = exports of virtual water
Water scarce nations can avoid producing ad exporting water intense products
Give two examples of the Virtual water trade
One steak = 4650 litres
Kenya growing flowers for UK supermarkets in times of drought
Explain Water conservation
Reducing water losses e.g through leakage/evaporation
Also about reducing consumption
Give an example of Water conservation
California - 96 million shade balls released in lakes to prevent evaporation ($250 over 10 years)
Environmentally damaging
Explain Recycling Water
Former wastewater sewage that has been treated to remove solids and certain impurities, and is then allowed to recharge the aquifer
Most locations = only intended fro non-potable use (irrigation, fire suppression)
Singapore + California - water given more advanced treatment and used for drinking
Debate over the extent to which all the pathogens and chemicals are removed after treatment
Give an example of Recycling Water
Singapore faced with persistent water shortages = has invested in treating and purifying wastewater using dual-membrane and ultraviolet technologies
Makes up 30% of their water supply
Explain Greywater
Domestic water - internally used (showers, washing machines) that can be used fro toilet flushing + other non-drinking uses
Potentially saves 30% on bills, but expensive to install (£5,000)
Give an example of Greywater
Oxley gate in Milton Keynes - 150 new build houses with greywater systems that can hold enough water for 15 flushes
Explain Groundwater management
Maintaining groundwater supplies potentially involving aquifer recharging
At a basic level - involves not taking more water out of an aquifer the is naturally replenished. Aquifers can be recharged anthropologically (deliberately by people) rather than naturally
Give an example of groundwater management
Mindaroo Australia
Upside-down weir has been built under a river to allow groundwater to accumulate
Give some benefits of recycled water
Sold to citizens at a cheaper rate
Saves potable water for drinking
Contains higher levels of nutrients to help fertilise pants through irrigation
Give 3 water conflicts (local, regional, international)
Ica Valley, Peru (local)
California (regional)
Nile Basin (international)
Explain water conflict at the Ica Valley, Peru
Industrial production of asparagus is depleting the area’s water resources so fast that smaller farms and families are finding their wells running dry
Exports of asparagus to UK supermarkets = unsustainable
Local water plummeted in 2002 when extraction overtook replenishment
Water levels fall by 8mm per year (fastest rate of aquifer depletion in world)
Water shortage expected to get worse as climate change shrinks the glaciers that feed into the Ica Valley river system
Give a positive for the Ica valley’s asparagus growing
Created 10,000 local jobs on the area and brings in $450m a year
Give the background water scarcity in California
Demand for water currently exceeds natural supplies
Spatial imbalance - 3/4 population loves in the South, but 3/4 precipitation falls in the north
Persistent high pressure in the Western Pacific Ocean stops storms reaching California between Nov-March, a time when the states get most of their rain
Droughts between 200-2007 and 2011-2015
Explain water conflict in California
Water rights are continually disputed. Native Americans have longstanding legal rights. Ownership of the Colorado river has long been disputed between Mexico and USA
Environmentalists are concerned that wetlands have been drained, natural habitat altered and fish stocks depleted
Northern Californians fear ownership of their water by the South, But Southerners are worried about the continuity of there supply
Explain the Nile Basin Water conflict
1979 - Egyptian president Sadat stated that “the only matter that could take Egypt into war agin is water” (Nile = matter of national security)
11 states in the Nile Basin, each with a. different plan for the river
The Arab spring has made it unclear wether Egypt is willing or able to enforce its long-held dominance of the region
Great Lakes = notoriously prone t cons;ict. Sudan + South Sudan still clashing over issues from 2005
All countries have paid economic and demographic growth - increased water demand
