3.3- Managing water supply

Water transfer schemes- Hard engineering 

• moving water from area of surplus to area of deficit

• done through pumping it through pipes, canals

Pros and cons

• water security increased in receiving area- good at small scale use

• volume of water transferred can be controlled to suit seasonal needs

• water stress increased in source area, infrastructure needed is expensive , enviornemtally damaging

Water transfer scheme in china- CASE STUDY

• diverting 45bill cubes of water annuanly from Yangtze river to south with 3 routes

• PROS- provides clean water to 20 cities, 100mil ppl benefit, industrial development continues increasing wealth, prevents overabstraction in south

• CONS- to construct central route, dam height was increased on Hanshui river causing more flooded land, destroying habitats.- decreased velocity of river downstream,

Three Gorges Dam- Hard engineering

• Dams block rivers so reservoirs of water build up

• Designed to control flooding on Yangtze, generate HEP- vital for Chinas growth, improve water supply by regulating river, reduces water insecurity

Pros and cons

• displaced 1mill people, flooded huge amount of land to form reservoir- damaging habitats

• Damages downstream ecosystems- holds back water and sediment making downstream land less fertile

Desalination plants- hard engineering 

• extracts salt from seawater to use it for drinking & irrigation #

• seawater is heated until water evaporates, leaving salt behind or done through reverse osmosis

Pros and cons

• Expensive, salt waste damages marine ecosystems

• Produces large amounts of energy

• As price of freshwater increases, countries are looking to sea for water, good for island countries like Maldives

Suistainable schemes of water supply- smart irrigation

• automated water saving sprinklers and drip irrational systems- water drips to plants through pipes go reduce waste

• soil moisture of plants is monitored- when reaches low level, irrigation of plant is automatically triggered

• genetic modification creates drought resistant plants that need less water

Recycling water

• recyled water used for irrigation, industries, toliets- if treated eniugh can be used for drinking water

• greywater is wastewater from homes- its clean so can be used ro water gardens, flush toliets without being treated first

Singapores holistic water management 

• has high standard of living and high water consumption 

• has low natural sources of freshwater

• has 5 desalination plants meeting 40% of country’s water

• uses scaled water pricing system- ppl who use high levels of water are charged more

Collect every drop of water- water consumption has reduced from 165 to 150 litres per day

Sharing Colorado river

• Colorado river supplied water for 8 states-  Climate change and demand has depleted storage by 50% and has been in drought since 2000

• New agreement made so instead of sharing water between states, amount of water available determines supplies to each state- California reduces it’s amount by 20%

What is the UNECE- water sharing treaty

• protect and ensure quantity, quality and sustainable use of trans-boundary water recourses by helping with co-operation 

• Was established by Helsinki to resolve water issues through equal share concepts 

What is the IWRM- Integrated drainage basin management 

• emphasises river basin as a logical unit for managing water recourses 

• based on achieving close cooperation between basin users and players.

• River basin treated holistically to ensure water is used with max efficiency, equal distribution of water among users

• IWRM works well at community level but nit larger river basin when transboundary level is involved like the Nile

What is the water framework directive and hydropower- water sharing treaty 

• agreed in Berlin to set targets to restore rivers, lakes to “good condition”