中国北方水资源供应问题--悉尼Essay代写范文

悉尼Essay代写范文:“中国北方水资源供应问题”，这篇论文主要描述的是在世界过去数十年的发展过程中，除了经济在不断的增长外，人口也呈现着快速增长的趋势，这也给环境带来了一定的负担，人们也为此付出了一定的代价，环境的恶化使得水资源短缺，部分的水资源出现了污染的情况，这在中国的北方尤为突出，如何解决人类社会的供应用水的问题，成为了我们思考的重点。

1. Introduction & Background

In the past few decades, the world's population and rapid economic growth, the environment has paid a huge cost. Continued growth, however, subject to the constraints of the deterioration of the environment, especially around water. Water is an important economic growth and well-being. In contrast, economic activity by the impact of water availability and quality. When water resources are limited or pollution, or improper unfettered economic activity and regulation, may lead to serious social problems. (Gleick,2008) The purpose of this report is to compare and recommend three requirements, which are the cost, environmental impact and social impact when using recycled water and built Dams for China./

At the same time, in China, these factors have come together and resulting in a more serious and complex water problem.(Gleick,2008) For instances, water quality deterioration, serious pollution by human, industrial wastes and irrigation.( Feng, 2007) China also has long suffered from the two extremes of floods and droughts. Some of the worst floods and droughts record have occurred in China.(Cooley, 2006). Li (2003) observes that the arid areas in China are mainly located in North of China which is the main region for food production. The plain contains 65% of the total agricultural land and 26.01% of the total population, however only 6.14% of the available water resources in this region. One can see the difficulties of irrigation in this arid region.( Lohmar& Wang& Rozelle& Huang& Dawe, 2003)

2. Presentation of Options

The diagram illustrates that how the water recycling project work.(Mission 2012 clean water, 2012)

As Hartman( no date) states that water recycling is using wastewater that has been treated, cleaned, and recycled, rather than being returned to the water system where it will evaporate and go through additional purification. It can be safely used for irrigation and other non-potable uses.  

2.2 Dams

A typical dam is built across the river, to prevent the flow of the river water in the lake. It has two main functions.The first one is the storage of water to compensate for fluctuations in the flow of the river and increases irrigation water for cropland below dam, or in demand for water and energy. Another role is to raise the upstream water level, so that the canal diversion or increase in ‘ hydraulic head '--- different height between the reservoirs and river Preparation surface. The dam by storing water, supply of agricultural, industrial and domestic water, as well as control flood , power generation and assist the inland shipping provide regular traffic and drowning rapids.(McCully, 2001)

3. Requirement of Water recycling and Dams

3.1 Cost

There is an example can be found in Australia, according to Olberding (2010) the Australian Academy of Science states that the city of Toowoomba needs to spend $68 million to a new wastewater treatment plant as part of its plan to use recycled water to supplement its water supply.

As WWF Global(no date) shows that dams in the 1990s was the annual expenditure between $32 and $46 billion. Throughout the 20th century dams was spent $2 trillion.

3.2 Environment impact

In addition to providing a reliable, local control of water supply, water recycling provides significant environmental benefits. By providing additional water sources, water recycling can help us to find ways to reduce the diversion sensitive ecosystems. Other benefits include the reduction of emissions, reduce and prevent pollution. Reclaimed water can also be used to create or enhance wetlands and riparian habitat. (United States Environmental Protection Agency, no date)

The dam's main environmental issues affecting biodiversity in the region. Other environmental impact include increase the water pollution, floods large cropland and forests even lead to earthquake.(Campbell-Hyde, no date)

3.3 Social impact

A negative perception can be seen of the general public around the using recycled water. Although this water is in fact has reached the safety of no-potable water, but the public still feel uncomfortable to using recycled water, despite the possible benefits. (Hartman, no date)

Thomson(2005) observes that the three gorges dam project will displace about 1.9 million people from their homes and also flooded some of the monuments and landscape。

4. Comparison of Water recycling and Dams        

4.1 Cost

Using recycled water, means an increase in the cost of additional processing facilities and pipeline transportation infrastructure. Local governments must establish and maintain water-recycling facilities, including the cost of labor and basic maintenance. They have to build and install pipes to collect the used water, also known as gray water, and then transport it to the recycling facility, as well as recycled water pipe line transmission facility. This is an easier goal in underdeveloped areas, but built city require the additional cost of tearing up roadways and buildings to install pipes. (Jenkins,2013）

The processed of reclaimed water treatment also have several costs. As can be seen from the table, the estimated costs of reclaimed water for several tertiary treatment processes. The cost is based on a flow of 114x103 m3/day where 28x106 m3/day of reclaimed water will be delivered for irrigation. (Asano, 2007).

Treatment process    Estimated cost, $/m3

Filtered effluent    0.05

Filtered effluent with flocculation    0.06

Tertiary with 50 mg/L alum    0.09

Tertiary with 200 mg/L alum    0.13 Source: Water Reuse: Issues, Technologies, and Applications.

In contrast, build dams are much more expensive than construction the water recycling plant. Especially for some older dams, which are require more frequent maintenance and the costs if repair and operate are very high. According to the website of Mission 2012 Clean Water(2012),by 2020, 85% of the dams in the United States will be half a century old and in need of repairing. A report by American Society of Civil Engineers(2009) estimated that 3,300 dams in the U.S. are unsafe, the Association of State Dam Safety Officials estimate that in the conditions of maintenance throughout the U.S. Could reach a total of $36.2 billion, the most urgent repair structure in the next 12 years is estimated to cost $10.1 billion. The Dam rehabilitation and maintenance of the bill proposed in 2007 is pending approval. If adopted, repair public dams would provide $200 million in five years.

Due to the fact that the affluent areas are mostly in developed regions of the east coast of China, however, the arid and agricultural land are occupy a vast area in north of China.(Wang & Wu, no date) Therefore, the method of water recycling is cheaper and more applicable in the northern region in China.

4.2 Environment impact

According to the United States Environmental Protection Agency(no date) , the total water needs and budget, it is greater than 75% of word’s estimated 40% the agricultural irrigation accounts. water demand and estimates that it is greater than 75% worldwide. Currently in use recycled water to irrigate crops in some states, but the quality of the water may be the concern of some agronomists. Usually higher concentration of chemicals in reclaimed water, groundwater or surface water. Regardless of the impact on crops depends on the crop type and concentration of chemicals high recycled water.(Blanc,2010)

In comparison, Jenkins(2013) comments that water recycling provides significant environmental benefits. It also provides an additional source of water used for various purposes. Firstly, by water recycling, local government can reuse a precious and limited resource and reduce the heavy burden of water reserves. Recycling water is particularly important in regions that suffering from the heavy drought or limited source of freshwater.

Another contribution of recycled water is that it has added benefit of agriculture industry. Because it has been through a less treatment process than drinking water. Recycled water contains higher amounts of certain chemicals, including nitrogen, which can help fertilize plants. This makes the recycled water better for watering crops than potable water, which may added chlorine or fluoride and can be harmful to plants. (Hartman, no date)

In addition, dam comes with some environmental impact. According to Thomson (2005), Chinese officials suggests that , three gorges dam, will electric output of 20 coal-fired or nuclear power plants. It can help reduce human dependence on coal, which can cause serious air pollution and the release of large amounts of greenhouse gasses into the atmosphere.

Alternatively, Campbell-Hyde(no date) explains that dam will be threat to the wildlife of the river. The dam will change the natural environment, therefore, a number of species will be affected by the project. Secondly and frighteningly, Dam may have been accompanied by a major earthquake, For instance, the three gorges dam tied to the one in May of 2008 which killed 87,000 people.

In arid regions, water is not only the most precious natural resources, but also the most important environmental factors in the ecosystem. (Wang & Wu, no date) The balance between economic development and environmental protection need to be control.(Edwards, no data) The northern region is China's major grain producing areas, it can be seen that the environmental impact is particularly important in this region. Water recycling has less environmental impact than built dam, which can also bring more benefits than the dam in north of China.

4.3 Social impact

Hartman(no date) concludes that the main disadvantage of recycled water is one of the potential health risks it may contain bacteria. Recycled water may contain harmful bacteria such as E. coli or other , which are transported to wherever the water is finally used. In the case of the field of irrigation, which raises the possibility of the outbreak of food-borne illness. Because of this, water recycling can not be widely accepted.

Thomson (2005) remarks that the example of the three gorges dam in China will help 15 million people living in the Yangtze River valley have benefits from flood protection. Furthermore, dams have also contribute to many social problems. Yangtze River Cruises (2009) indicates that Chinese officials have estimated that the reservoir will inundate 2 cities, 11 counties, 140 towns. About 23800 hectares, more than 1.1 million people are in need of resettlement. What is more, the Three Gorges project will also submerge some of China's most famous historical scenery and tourist attractions.

5. Conclusion

To summaries, water is one of the most challenging natural resources in the current and future all over the world. For China arid regions sustainable development of agriculture, a healthy economic development, water is the key to success. (Wang& Wu, no date) This report has examined the provision of water in north of China. It has considered three requirements, which are costs, environmental impact and social impact when using water recycling and built dams in north of China.

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