<
>
Download

Aufsatz
Geowissenschaften

Wisbech Grammar School

2014

Christiane T. ©
3.00

0.10 Mb
sternsternsternsternstern_0.25
ID# 40540







Large Scale water managemenet projects

Geography Homework


Contents

a)Explain how physical and human factors have contributed to the variation in water scarcity shown 1

b)Using named examples, assess the contribution of large-scale water management projects in increasing water security3

 

a)   Explain how physical and human factors have contributed to the variation in water scarcity shown (10) (Jan 2010)

The causes of water scarcity are varied.  Some are natural and others are a result of human activity.  The main cause of growing water scarcity is growing demand resulting from population growth.  The population growth rate for all countries in South Africa varies between 2.2% to 3.8%.  The major increase in demand is due to the development needs of the growing population and, primarily, from the need to grow sufficient food to feed the increasing population.

There are 48,000 large dams around the world, which alter the natural flow of a river, often improved water and energy security for some, but at the expense of others – such as developing countries in Africa.  1.1 billion people worldwide lack access to clean water, and a total of 2.7 billion suffer from water scarcity for at least 1 month a year.

Areas such as North Africa and the Middle East have desert-like climates meaning their supply is limited due to the high temperatures making the area dry.  But, areas on the equator with high temperatures and non arid climates tend to have the least scarcity as they have high rainfall.

Human activity is having a negative effect on the environment and water supply.  There is over-abstraction for human domestic, agricultural and industry needs.  There is pollution of groundwater due to sewage disposal contaminating the underground water supply, which is expected to cause 135 million deaths by 2020 due to contaminated water diseases such as hepatitis.  Chemicals from fertilisers used by farmers also contaminate groundwater supplies – this can cause eutrophication thus contaminating water supplies.  Each year there are 400 billion tonnes of industry waste, which also contributes to water contamination as only a small proportion is disposed of in an environmentally friendly manner.  Higher temperatures at the equator cause water shortages due to the shorter distance from the earth to the sun.

There are any factors causing economic water scarcity in areas such as the USA, Russia, Europe and the Australian coast.  This is caused by political crisis’, such as lack of government investment, water privatisation, TNC’s using water, e.g. Cocoa Cola using fresh groundwater in Africa to clean their bottles instead of local people using it to live, increasing usage and the poverty trap.  12% of the world’s population consume 85% of the world’s water supply, so the other 88% only have 15%, therefore causing many developing countries to suffer from water scarcity.  Only 1% of the world’s freshwater .....

Although it meets some of the criteria that makes water security, you could argue it hasn’t resulted in ‘clean’ and affordable supplies, also the huge environmental, economic, cultural and social impacts it has caused may prove it to be an unsustainable scheme.  Up to 1.2 million people, 1,600 enterprises, 140 towns and 4,500 villages have been relocated; and many of these people haven’t received compensation – over $30 million of funds set aside for this have been taken by corrupt local officials, but, this could be used for the greater goods as it may be spent on flood control.  The environmental impacts have been devastating; the dam has trapped a large amount of untreated waste each year, which has impacted the biodiversity in the area.  The dam has interfered with aquatic life e.g. the Siberian Crane and the white flag dolphin, which are threatened with extinction.  Fish stocks have also declined as the number of phytoplankton they feed has fallen.  Archaeological treasures have also been drowned e.g. the famous Zhang Fei Temple.  The port at the head of the lack may become silted up as a result of increased disposition, which could cause the development of a delta at the head of the lake, which could affect the longevity of the scheme.


Large-scale water security would appear to create food security through irrigation projects such as those in Egypt.  But do they?  Another scheme, which has attempted to improve water security, is the Aswan High dam in Egypt.  Most of Egypt only receives less than 125mm of rain a year and the Nile is the only river in Egypt therefore the management of the Nile to create water security is vital.  Work started on this dam in 1968 and by the end of that year the reservoir, Lake Nasser, was full.  It has created a reliable source of water for virtually all Egyptians (60 million).  This secure water supply has also had a positive impact on agriculture as it has extended the amount of irrigated land along most of the desert margin of the valley delta.  It has increased crop yields and provided locals with more cash crops to be exported.  Although this project isn’t at the same large scale as the Three Gorges, its negative impacts are very similar, suggesting it hasn’t increased water security.  The water quality has declined because of pollution by fertilisers.  There has had to be a lot of resettlement – formerly, the area was inhabited by 120,000 people, who were forced to leave and seek a new home and lifestyle.  It has also reduced the amount of silt that is being deposited which creates a loss of soil nutrients.  It has also increased erosion – riverbanks are collapsing because of it, resulting in loss of agricultural land.


Water stress is a massive problem in California and It depends on 3 major water supply lines in order to supply its growing industry and population with water.  The SWP and CVP schemes provide drinking water for about 22 million Californians.  Water is transported 500km across the desert via a system of aqueducts from Lake Havasu in Phoenix and Tucson in Arizona.  The water has to be raised by 400m using several pumping systems along the route, using HEP generated by the Colorado River.  However, by the time the water reaches Tucson it has become very salty, therefore it has to be treated before it can be used.   This project only provides security to California due to the wealth and investment that can be made by the USA.  The methods of controlling the Colorado River are unsustainable, creating social, economic and environmental implications.  Wetlands have been drained, natural habitats altered, and fish stocks depleted, all to secure water supplies.  Pollution is also a massive problem as well as the over extraction of groundwater and increase salinity.


The major negative impacts involved with large-scale water management projects outweigh the benefits in some cases e.g. the Three Gorges dam, as it hasn’t actually improved water security.  More efficient, small-scale projects may be the way forward in .....


| | | | |
Tausche dein Hausarbeiten