How are mega dams being used as a hard engineering strategy for water supply management
- 60% of major rivers are dammed (5000 mega dams)
- Mega dams have the facilities to store 15% of annual global runoff, however losses from evaporation are high
- They are versatile in that they can provide irrigation, flood control, HEP and water supply
What is an example of a mega dam being used as a hard engineering scheme
An example of a mega dam being used for a hard engineering scheme is the three Gorges dam on the Yangtze River in China
- It makes the river navigable,regulates flow and generates HEP
- It is contraversial and very expensive
- It does enable water to build up and be diverted to Northern China via the South, North Watar transfer project
- 632km2 of land has been flooded to form the reservoir
- 1.3 million people have been relocated from 1500 villages and towns
- Decomposing vegetation releases methane which is then released when the water passes through HEP turbines
What is an example of a water transfer scheme (hard engineering)
-Chinas South-North transfer project is an example of a water transfer scheme
-It diverts water to the Northern Chinas plain Arable land
It is set to transfer a total of 44.8 billion cubic metres of water per year
-It has a 50 year construction with a $100 billion cost
-345000 are due to be relocated with 1300 km of canals
-There are risks of over draining southern China, worsening water quality and increasing pollution ( making worse as the Yangtze River is already severely polluted
-However it also does reduce groundwater abstraction and solves water shortages in Beijing and boosts economy
What is another hard engineering method of managing water supplies
- Desalination is another hard engineering process aiming to manage water supplies
- It provides a predictable and reliable supply of water
- It uses saltwater and is therefore a sustainable process as it conserves supplies for further generations
- It is still very costly however and does have a major ecological impact on marine life
What is an example of an area using desalination schemes to manage water supplies
- Israel is an example of an area using desalination as a route to managing water supplies
- Five desalination plants were opened in 2013, taking water directly from the Mediterranean
- it aims to provide 70% of Israel’s domestic water supplies by 2020
- each plant requires its own power station howver which adds to co2 emissions ( but much of the energy used is solar)
- It also produces vast amounts of salt/ brine which contains anti scaling agents that harm ecosystem
- It produces up to 600 tonnes of potable water per hour
How else do Israel manage their limited supplies
- Smart irrigation - this involves using drip systems which allow water to drip slowly to plants roots through a system of valves and pipes - reducing waste and evaporation
- recycling sewage water for agricultural use (65% of crops are produced in this way
- Reducing agricultural consumption and importing water in food as virtual water ( water in high water usage food)
- adopting stringent conservation techniques
- Managing demand by charging real value prices for water which reflect supply costs which include ecosystem management
How does Israel acquire new supplies of water
- Israel acquires new supplies by importing 50 million tonnes of water per year by ship from Turkey
- piping seawater from Red Sea and Mediterranean to new desalination plants
What does water conservation aim to do
-Water conservation aims to manage demand for water supplies in various sectors
What sort of water conservation techniques are being adopted in agriculture
- In agriculture, sprinkler and surface flood irrigation schemes are being replaced by automated spray, drip and smart irrigation schemes
- Repairing leaks is also stopping water loss
- Recycling city waste water ( grey water) can be used to irrigate
- GM crops are being bred to be water resistant
- hydroponics (growing in controlled greenhouse environments) are sustainable water wise but energy intensive
- Agronomists have designed algorithms to monitor water use efficiency
What is the role of intermediate technologies and specialist NGOs in water conservation
- Specialist NGOs such as farm Africa and waterAid help farming communities develop strategies to combat climate induced water scarcity
- intermediate technologies can also provide solutions such as ‘magic stone’ initiatives in the Sahel and rainwater harvesting in Uzbekistan
What is the role of industrialisation in water conservation
- Rapid industrialisation has contaminated water sources and aquifers but some companies have reduced water consumption e.g at Coca Cola bottling plants
- Zero liquid discharge rules can stop waste water pollution
How can water be conserved domestically
Domestic water consumption can be reduced and supplies conserved using rain harvesting with water butts, sharing baths, reducing toilet cistern capacity and eco kettles
- In times of drought, conservation can be inforced by hosepipes bans
- Climate proofed gardens with drought resistant plants can survive water stress
- Filtration technology (e.g dual membrane technology) can reduce water usage
- Attitudinal changes can reduce domestic demand, through smart metres
What is involved in water restoration
- Sustainable water management can involve restoration of damaged rivers, lakes and wetlands to their natural state
- At a local level this can involve restoring meanders, replanting vegetation and using sustainable water coarse management alternatives e.g partial restoration of south Iraq marsh drained by Sadaam hussien
- The schemes are environmentally sustainable and have socio cultural benefits
What are examples of water sharing treaties and frameworks
- UNECE ( United Nations economic commission for Europe) water convention aims to protect and ensure quality, qauntity and sustainable use of trans-boundary’s water resources, it was established in Helsinki in 1992-96 to resolve water issues and apogee the IWRM at basin scale
- The EU WFD (water framework directive) and hydropower was agreed in Berlin in 2000 to set targets to restore water sources to good condition and assess all environmental risks of new developments
What is the IWRM
The IWRM is the integrated water resource management
- It is a policy setting out that water resources are an integral natural component and a socio-economic good
- It promotes the co ordinated management of water, land and other resources in a sustainable way
How prevalent is international co operation
- Despite the potential for conflict over international waters, international co operation is much more common than conflict
- Only 5.3% of all drainage basin agreements since 1948 have resulted in hostile military, political,diplomatic or economic acts, with most resulting in mild verbal support,official, economic, scientific or diplomatic support or water treaties e.h India and Pakistani signed the indus water treaty in 1960 and since it is has been honoured
- However conflict is more likely to develop where water is one of many factors causing disputes
What are the pros of water sharing treaties and frameworks
- They encourage international co operation and peace
- They support shared goals such as environmental protection and social development
- They can protect from natural threats such as drought and flooding
- They increase justice for downstream nations
- They can settle disputes to follow other political priorities
What are the cons of water sharing treaties and frameworks
- Water treaties can trap countries in unfair and outdated terms of resource split with changing factors e,g population
- They can reduce national autonomy and control by the government
- They can be initiated by corrupt proceedings creating injustice
- They can be difficult to enforce
What is the context behind the Colorado river basin case study
- The Colorado River Bain drains 7% of the USA and supplies water to 8 US states
- It contains 11 major dams and reservoirs, irrigating 1.4 million hectares of farmland and providing drinking water for 50 million
- It controls flooding and produces HEP
- demand and climate change has depleted storage to 48% and average annual flow has decreased by 15% since 1990
What agreement was made for the basin (1922) and what are the problems with this
-an agreement from 1922 ( Colorado Compact) was made but it’s now outdated as population is increasing and average rainfall was 10% higher
What is pressures are building on the river
- Mexico takes 10% of total flow
- Lower basin states take 50% of water
- Upper basin states fall 10% short
- California takes 20% more than its allocation
- Native Americans are owed 5% but could claim more
What new basin agreements have taken place in Colorado
- By the 2007 agreement the 7 US states agreed to divide the shortages and have to reduce usage (California has reduced extraction by 20%)
- In 2012 the minute 139 agreement between USA and Mexico giving it the right to store water in lake mead . Water providers will then be allowed to purchase this water by improving mexicos canals and storage infrastructure
- In 2017 by the minute 323 agreement the us invested millions of dollars in water conservation projects in Mexico such as plugging leaks and implementing water efficient farming technology
What other actions and policies are being considered involving water restrictions
- Domestic conservation ( repairing leaks, metering supplies )
- Re using waste water
- Storm drains to redirect rainwater to irrigation
- reducing irrigation (agriculture uses 80% of californias water
- Smart planning to ensure housing is only built in water supplies areas
