water cycle

• hard management: 3 gorges dam: pros -

  • designed to control flooding to the Yangtze + improve water supply by regulating river flow
  • generates HEP + makes river navigable
  • enables surplus water to build up and be diverted to the north of china through the south-north water project
  • electricity generated by this is vital for chinas growth
• hard management: 3 gorges dam: cons -

  • 632km2 of land flooded to form reservoirs
  • 1.3 million people relocated from 1500 villages and town
  • reservoirs water quality is low because water from industry sewage and farms enters from upstream
  • decomposing vegetation in the reservoir produces methane which is released when water passes through the HEP turbines
• hard management: china south-north water transfer: pros -

  • aims to deliver 25 billion m3 of freshwater per year to the drier north by 2 routes (central and eastern) - 3rd western route is currently being planned
  • 2/3rds of the farmland are in the north and 80% of the water is in the south - provides opportunity to distribute water to ensure agriculture and water security for the nation
• hard management: china south-north water transfer: cons economic -

  • estimated to cost US80 billion - before maintenance costs and water prices are considered
  • likely to be too expensive for the farmers resulting in them continuing to use groundwater despite the scheme
• hard management: china south-north water transfer: cons social -

  • over 300,000 people have been displaced for the construction of the water transfers central route
• hard management: china south-north water transfer: cons environmental -

  • transferring water via water transfer does not address the main causes of water shortages in the north - the north has a limited water supply because of the pollution of water sources, water inefficient agriculture and poorly managed use for industry
  • by removing water from the Yangtze it may further reduce discharge levels - the impacts for the river ecosystem will be devastating, in addition too these already caused by the 3 gorges dam
• hard management: Israel desalination plants -

  • source of salt water is mediterranean sea
  • 2013 - had 5 fully functioning desalination plants
  • by 2020 - aims to supply 70% of its domestic water supplies from desalination plants
• hard management: Israel desalination plants: pros -

  • provide a supply of water that is both reliable and predictable
  • able to produce up to 600 tonnes of clean drinking water an hour
• hard management: Israel desalination plants: cons -

  • so energy exhaustive that each plant needs its own power station
  • by-product of the salt water is brine (a very salty liquid) which can be extremely damaging to the environment
• sustainable management: smart irrigation -

  • provides crops with below the optimum water levels during the growth stage so they become less sensitive to the lack of water
  • crops produce the same quality and quantity produce whilst using less water
  • eg a way water is regulated and restricted is through drip-feeding - water goes directly into the soil next to the roots of the crops, preventing waste and a loss of water via evaporation
• sustainable management: smart irrigation: australia -

  • use of smart irrigation for fruit trees has resulted in a 60% increase in water productivity
  • improvement has been seen in fruit quality and also in retaining the yield size by using the smart irrigation technique
• sustainable management: singapore recycling of water: background -

  • 5.4 million population and only 710km2 of land
  • 2,400mm of precipitation a year but there is limited land availability for collection and storage of rainfall
  • high temperatures mean high evaporation rates and also a lack of groundwater resourced despite the high levels of precipitation
• sustainable management: singapore recycling of water: techniques -

  • water agencies invested in several ways to ensure its water security
  • local rainwater collected via drains, canals and storm water collection points before being treated to become drinking water
  • NEWater scheme treats and purifies used water producing high-grade recycled water - 4 plants meeting 30% of countries needs - plans to raise it by 55% by 2060
  • signed agreement until 2061 to import water from Malaysia
  • desalination plants
• sustainable management: sand dams Machakos district Kenya: during rainy season -

  • when river is flowing, sand is trapped behind the 1m high dam
  • water gets trapped in amongst the coarse sand particles
• sustainable management: sand dams Machakos district Kenya: during dry season -

  • sand stops the water from evaporating when it gets hot
  • locals extract the trapped water by:
  • digging wells
  • channeling water through the dam and tapping it off on the other side
  • digging holes
• sustainable management: sand dams Machakos district Kenya: advantages -

  • sand dams are cheap to construct
  • local materials are used to build the sand dams
  • dam height can be increased each year so that more sand and more water are trapped by it
  • water recharges the whole area leading to an increase in vegetation surrounding the dam
  • locals trained by water charities to make the dams so that they can be self-sufficient going forwards
• Colorado river storage project: background -

  • Colorado river is 233km long with 97% of it flowing through the USA and rest through Mexico
  • levels of precipitation vary across the Colorado river basin - starts in the Rocky Mountains and flows through semi-arid areas to the gulf of California in Mexico
  • increase in population urbanisation and agricultural demands put pressure on river as water source
  • climate change resulted in lower precipitation and areas of drought across the Colorado river basin which adds further pressure
• Colorado river storage project: management -

  • 1956 - project established to develop regulation of the Colorado river between the states for irrigation development and HEP production - now 29 dams along the course of the river
  • in 1990 the states in the lower course of the Colorado river used their full allocation for the first time
• Colorado river storage project: resource pressure -

  • despite the project providing hydroelectric power, flood control and water storage - no methods that can sustainably remove all the water needed from the Colorado river
  • individual states are looking for alternative solutions and sources
  • nevada is negotiating for extra water allocation
• Helsinki UNECE water convention: aim -

  • improve and protect water quality and quantity in a sustainable manner whilst resolving and improving co-operation for trans-boundary water resource issues
• Helsinki water convention: result -

  • integrated water resource management approach was established
  • the IWRM determines what water resources are essential for the ecosystem and what resources are required for efficient social-economic development
  • the IWRM is an alternative to top-down sector by sector management that has a holistic approach
• Berlin rules on water resources -

  • august 2004 - international law association (ILA) approved the Berlin rules on water resources
  • Berlin rules state how freshwater resources should be shared whether nationally or internationally adopts nine water management principles
• Berlin rules on water resources: principles -

  1. public right to be involved in decision making
  2. resources managed to promote the availability of supplies
  3. whole drainage basin needs to be considered
  4. economic social environmental needs must be met
  5. environmental damage limited
  6. everyone must co-operate over shared resources
  7. everyone is to receive a fair share of water
  8. upstream developments are to be controlled
  9. all players have an equal position