5.9 Managing Water Supply Flashcards
5.9a Hard Engineering
techno-fix
a
5.9a Hard Engineering
hard-engineering
high level s of capital and technology are needed to carry out these projects
economic costs are high (multi-billion) however there are often economic benefits across a large area
5.9a Hard Engineering
water transfer schemes
WATER TRANSFER IN CHINA CASE STUDY
water transfer schemes involve the diversion of water from one drainage basin to another (inter-basin transfer), either by diverting the river itself or by constructing a large canal to carry water from an area of surplus to an area of deficit
controversy in large-scale, high-tech transfer schemes because they may lead to long-term changes to local and regional hydrological conditions (increasing flood risk, damaging fish stocks, spreading leases and pollution, affecting river environments)
SPECIFIC ADVANTAGES AND DISADVANTAGES IN CASE STUDY
5.9a Hard Engineering
water transfer schemes: advantages
water available for development
reduced water scarcity in the receiving area
large scale projects have significant impacts
5.9a Hard Engineering
water transfer schemes: disadvantages
source experiences drop in flow of up to 60% as a result of diversion/ transfer
original river experiences low flow and becomes polluted, increasing impact on ecosystems’s salinity
climate change can combine with low flows to lead to water scarcity
greater availability of water in receiving area leads to greater use and promotes unsustainable irrigated farming by agri-businesses
nitrate eutrophication and ecosystem destruction due to pollution transfer in the transfer scheme
5.9a Hard Engineering
mega dams
nearly 60% of the world’s major rivers ar impeded by large dams
China is the world’s leading dam builder (46% of the world’s total) and, as part of its FDI programme in Africa is building many more mega dams
5.9a Hard Engineering
mega dams: advantages
multipurpose schemes have multiple benefits, providing irrigation, HEP and flood control, as well as domestic water supply
produce clean energy, which is increasingly popular because of rising concerns about global warming from greenhouse gasses
5.9a Hard Engineering
mega dams: disadvantages
evaporation losses are very high as many dams are located in semi-arid areas
5.9a Hard Engineering
desalination plants
Saltwater from the sea is either evaporated to leave behind the salts or undergoes reverse osmosis, where water is pushed through a membrane to separate it from salts.
5.9a Hard Engineering
desalination plants: advantages
recent breakthroughs in technology (reverse osmosis) make desalinating far more cost effective (given that freshwater costs are rising), less energy intensive
easy to implement on a large scale
the relative costs of desalination may decrease further as technology advances
can run on renewable energy from solar panels
more viable than large water transfers
5.9a Hard Engineering
desalination plants: disadvantages
high initial costs
environmental concerns, particularly for maritime ecology
5.9b Sustainable water management
restoration of water supplies
restoration of damaged rivers, lakes and wetlands, to return water environments to their natural states
local scale: restoring meanders, replanting vegetation, using sustainable methods to manage water courses
larger scale: restoration of entire rivers, marsh areas
water restoration schemes are environmentally sustainable and have socio-cultural benefits to the communities living there, but disputed as to their economic sustainability
5.9b Sustainable water management
water conservation
LOTS OF DETAIL IN HODDER TEXTBOOK
a
5.9b Sustainable water management
water conservation: smart irrigation
aim to be ‘more crop per drop’ by supplying minimum amount of water for maximum yield
Israel is a pioneer of water conservation
5.9b Sustainable water management
water conservation: recycling of water
recycling of water in areas of water scarcity to ensure feasibility because grey water (waste sink or washing water) does not need to be of drinking-water quality
