5.9A - Hard Engineering
The pros and cons of the techno-fix of hard engineering schemes to include water transfers, mega dams and desalination plants. (China)
Because of the wide range of players involved in the use of water resources, there are inevitable conflicting views as to what constitutes the best approach to the management of these resources. For example, economic players, such as businesses, typically opt for hard-engineering schemes, whilst environmental players, such as conservation organisations, favour a more sustainable approach.
Hard engineering schemes require high levels of capital and technology. There are now up-and-running long-distance water transfer schemes; mega dams; and clusters of desalination plants.
Water transfers
Water transfer schemes involve the diversion of water from one drainage basin to another, either by diverting a river or constructing a large canal to carry water from one basin to another.
The most publicised of these is China's South-North Transfer Project, which is currently under construction. The idea of moving water from an area of surplus to one of deficit seems simple, but issues include:
Source area
The most publicised of these is China's South-North Transfer Project, which is currently under construction. The idea of moving water from an area of surplus to one of deficit seems simple, but issues include:
Source area
- Experiences drop in flow of up to 60% as a result of diversion/transfer
- River experiences low flow and becomes polluted increasing impact on ecosystem's salinity
- Climate change can combine with lower flows to lead to water scarcity
- Availability of water simply leads to greater use
- Increased use for development, e.g. golf courses, tourism
- Promotes unsustainable irrigated farming by agri-business
- Nitrate eutrophication, salination and ecosystem destruction. Pollution transfer.
Mega Dams
Nearly 60% of the world's major rivers are impeded by large dams, perhaps most notably the Colorado, Nile and Yangtze. While the capital costs of such dams are immense, this hard-engineering solution to water shortages has other drawbacks, such as high evaporation losses from the water surface, the disruption of the downstream transport of silt and the displacement of people.
Desalination
Given the increasing pressure on freshwater resources and their shortage in the drier parts of the world, it is not surprising that some countries are looking to the oceans for water. Desalination is the process by which dissolved solids in sea water are partially or completely removed to make it suitable for human use. It has been undertaken on a small scale for centuries, but recently there have been technological advances in the process, most notably:
Desalination is an expensive process; it requires inputs of advanced technology and energy. However, as the price of freshwater rises, so some countries will look increasingly to the seas for their water supplies. Middle Eastern states like Saudi Arabia, Kuwait, Israel and the UAE have already done so.
Because of its inputs, desalination is classified as a hard-engineering solution. However, it is a sustainable process, although it does have an ecological impact on marine life.
- development of the process of reverse osmosis
- pioneering work on carbon nanotube membranes
Desalination is an expensive process; it requires inputs of advanced technology and energy. However, as the price of freshwater rises, so some countries will look increasingly to the seas for their water supplies. Middle Eastern states like Saudi Arabia, Kuwait, Israel and the UAE have already done so.
Because of its inputs, desalination is classified as a hard-engineering solution. However, it is a sustainable process, although it does have an ecological impact on marine life.