1
) dam construction
"
profit
"
Dams have two main functions. One is to store water to compensate for the change of river flow; The second is to raise the upstream water level and let the water flow into the channel.
Or increase
"
water head
"
That is, the height difference between the reservoir water surface and the downstream river water surface. The storage of water and the generation of water head enable the dam to control flood, generate electricity and work.
Provide water for agriculture and life, and improve river navigation by stabilizing water flow and flooding rapids. Other purposes of dam construction include reservoir breeding, leisure activities,
Like boating
(
Mike Gu Lei,
1996)
1
.
1
Control flood
In the lowlands
Rivers often cause floods.
Natural floods are still the most frequent in the world.
、
One of the most harmful disasters.
1992
~
1996
Annual average flood impact.
6 500
The normal life of ten thousand people is more harmful than any other disaster.
(
World commission on dams,
2000)
Damming can make the distribution of water flow more uniform, thus becoming one of the measures to alleviate flood disasters. The flood regulation reservoir reserves and stores part of the flood,
Thereby reducing the destructive flood peak.
(
Kandsevich，
1998)
. This reduces the loss of water flow and flood in the lower reaches of the reservoir. exist
70
Multiple countries
Home, about
13
% of the high dams have flood control function.
1
.
2
irrigate
Irrigation is an important means to turn barren areas into fertile areas that can feed a large number of people. In today's world, irrigation is fresh water
The maximum consumption and utilization mode is related to food production and food security. appointment
1
/
five
60% of farmland is irrigated, and irrigated agricultural output accounts for the world agricultural output.
close
40
%。
The first dam was built with reference to the Nile water in Egypt, and the location of Memphis was determined. Many ancient earth dams, including those built by Babylonians.
Many earth dams have been built.
It is part of a well-designed irrigation system.
Up to now, half of the high dams in the world are specially or mainly built for irrigation.
According to recent estimates, at present, the whole world
30
%~
40
% of irrigation water depends on dams. In some areas, irrigation has become an indispensable factor for future development.
Less infrastructure. For example, Egypt, almost
100
% irrigation is provided by the dam, most of which comes from Aswan High Dam.
1
.
three
supply water
With the sustained and rapid growth of the world population, water supply will remain an important issue. One of the ways to provide reliable water supply is to build on the river.
Dam, forming a reservoir, stores excess water in high-flow period and uses it in low-flow period.
(
Lasach,
200 1)
The purpose of many reservoirs is to provide reliable water supply to meet the needs of rapidly developing cities and industries, especially the demand for natural groundwater resources.
The source and existing lakes or rivers are not enough to meet all the needs of arid areas. For example, in Saxony, Germany, the reservoir is
200
Ten thousand people supply
View from a height or a distance
40
% water.
1
.
four
generate electricity
As a low-cost and renewable power resource, hydropower is accepted and advocated by human beings. This is a kind of non-consumable water. Once built,
Hydropower has low operating cost and long service life, especially for decisive river projects and reservoir projects without considering siltation.
(
World commission on dams,
2000)
. It is considered as a clean energy source, just like biological, geothermal, wind, wave and solar power generation.
(
Kandsevich，
1998)
Hydropower is an important reason for many countries to build dams, especially for developing countries, hydropower is an important part of economic development.
At present, hydropower accounts for the world's electricity supply.
190k
150
Every country has developed hydropower.
1
.
five
shipping
Compared with road, railway and air transportation, sea transportation is the cheapest mode of transportation, with the least pollution, no need to be expensive and not conducive to the ecological environment.
Environmental infrastructure
(
Such as highways and railways.
)
. Damming can make the river flow pattern more uniform and form navigation places in the reservoir area or downstream of the reservoir.
Help to improve shipping. Shipping water is non-expendable water in rivers. The shipping cycle of rivers with dams is longer than that of rivers without dams.
1
.
six
other
Other benefits of dam construction include recreation and fishing. In addition, it is also related to food security, local employment, technological development and rural supply.
Electricity, natural and social infrastructure
(
Such as roads and schools.
)
Popularize and popularize.
2
) dam construction
"
shortcomings
"
If water conservancy and hydropower projects, especially large-scale projects, have so many advantages, why do so many people question them?
Large reservoirs have been built.
Does a large amount of water storage in the upstream destroy the ecological balance?
Is it easy to induce earthquakes?
These problems are mainly aimed at building, water conservancy, hydropower and electrician.
Possible ecological and environmental problems and immigration problems.
2
.
1
induced earthquake
A large amount of water impounded by the dam will exert great pressure on the reservoir and dam body. Is it the cause of the earthquake?
1982
United States Army
Corps of engineers
(U
The late mother
)
He studied the influence of dams on induced earthquakes. After studying several dams,
USACE
Discovery induction site
There is no direct connection between the earthquake and the dam construction. According to the report, according to the study of Coiner Dam and Aswan Dam, so far,
So far, no evidence of dam-induced earthquake has been found. In addition, another related study in the United States has reached the same conclusion, building Quesna.
The dam and Aswan dam are not directly related to the earthquake. Every earthquake near the reservoir is induced by the reservoir, but
This is just people's wrong guess.
2
.
2
Water infiltration
Another negative effect attributed to the construction of reservoirs and hydropower projects is the water seepage around the project, which is worrying.
The infiltration of water leads to the rise of groundwater level around the project, which leads to the salinization of land. India
CWC 1998
According to the data compiled by 1998, it is affected by water infiltration.
The ringing land * * * has
85 1
ten thousand
hektare
Compared with the increased irrigation area
10
% is still young. Besides, it can't only be attributed to the construction of reservoirs, salinization and water.
The increase of land affected by infiltration is not directly related to reservoir construction. The direct cause is over irrigation, improper drainage and insufficient water resources in some areas.
Poor management. With the increase of groundwater level, the vegetation in the whole area increases, and it is lush everywhere, but it may not harm some deep-rooted trees.
Impact, need to transplant. In addition, the humid environment around the dam site creates good conditions for crop growth.
2
.
three
Soil erosion
Because of cutting down trees for fire, heating and other purposes, a large number of forests have begun to degrade, and soil erosion is becoming an increasingly acute problem. But,
Watershed management and development help to prevent soil erosion. In addition, the power generation of hydropower stations can reduce the demand for wood for fire and heating, and reduce
The number of trees cut down. In addition, with the development of watershed management, large-scale afforestation activities are often needed to prevent soil erosion.
2
.
four
Reservoir resettlement
Resettlement in reservoir construction area and flooded area has become a very complicated problem. Most reservoir projects are located in backward education and residential areas.
In remote mountainous areas where people lack the means to make a living, people's living standards are very low. However, once these villages are consolidated by building reservoirs or other related development activities,
When a given place becomes an immigrant, social changes will take place immediately. In the past few years, Indian engineering construction management authorities have implemented immigration regulations.
Planning not only compensates the land and its attachments, but also provides better living conditions for immigrants. The construction of the reservoir drove away the immigrants.
The home where generations have lived, they will bid farewell to the past, culture, customs and traditions. However, we must not forget that the history of immigration has been going on.
Thousands of years. More and more people move from rural areas to cities. With the great influence of the media, different cultures are merging. Extend in all directions
Road and railway networks connect people in different areas. Even without immigrants, people's customs and traditions are changing. But,
Regardless of all these factors, the resettlement of reservoir immigrants should be like this, that is, there is no cultural and social change in their new residence.
A sense of isolation and no sense of economic discrimination. Immigrants should be placed in areas similar to the original geographical and social conditions as far as possible.
So that immigrants will not lose their social ties and sense of belonging. The resettlement plan must be formulated and implemented in detail, with the aim of being as comprehensive as possible fundamentally.
Considering all possible problems, we should ensure that the living standard of immigrants is higher than that before immigration.
2
.
five
Investment benefit
The environmental impact investment of thermal power accounts for the total project investment.
seven
%, and hydropower is
1
.
38
%~
four
.
five
%。 Besides. It can be used in water conservancy and hydropower projects.
The direct benefits of power generation, irrigation, flood control and water supply are analyzed, but some indirect benefits that cannot be quantified are not considered.
For example, shipping, fishery development, tourism, increasing employment and reducing poverty. Hydropower is the cheapest energy source in long-term operation, because it is not needed.
If you want to invest in fuel, you can also think that the increased investment is zero. because
It can be said that the concept that hydropower projects need higher investment is a misunderstanding based on wrong assumptions. Thermal power generation needs things like coal and oil.
Fossil fuels, and a large part of fossil fuels need to be imported, which leads to a large loss of foreign exchange reserves. On the contrary, hydropower projects do not need to be operated.
It needs a lot of fuel, so this part of the investment can be ignored. The electricity bill paid by consumers consists of two parts: the fixed part
(FC)
Represents a pair of electricity
Payment of factory input capital, energy composition
(EC)
Represents the payment of fuel input during operation. In the early days, all hydropower and thermal power resources
The principal is in the same school.
4 000
~
5 000
Ten thousand rupees/
megawatt
The scope of. The fixed composition of hydropower and thermal power tariffs decreases with time.
Until it is paid off. Due to rising fuel prices, firefighters
The energy composition of electricity charges is increasing, while the energy composition of electricity charges for hydropower projects can be ignored. Therefore, hydropower projects
Compared with thermal power engineering, it has smoothness.
(
Average
)
The advantage of lower price. In other words, due to rising fuel prices, thermal power prices will refer to
The digital form has increased. In fact, the investment of all hydropower projects may be slightly higher than that of thermal power projects at the beginning, but it will be invested over time.
Will plummet. If the power generation costs of hydropower projects and thermal power projects are comprehensively compared, it will be found that hydropower generation is more economical. Besides, in the long run,
During operation, hydropower stations have unique advantages in providing practical and flexible power, such as providing peak-shaving power at a very low price.
Hydropower can provide various forms of power supply according to various demands, while thermal power generation is impossible because thermal power generation is shut down and restarted.
The unit will cause great energy waste.
2
.
six
design cycle
The design cycle of hydropower projects is indeed longer than that of thermal power projects, but the service life of hydropower projects is more than twice that of thermal power projects.
The long design cycle of hydropower projects may be due to the following reasons:
( 1)
It takes a long time to determine the design scheme, for example, hydrological data collection and analysis, topographic survey, etc.
(2)
Requires a large number of institutions to participate;
(3)
It takes a long time to discuss and determine the ecological and environmental impact of the project;
(4)
It takes a long time to formulate and implement a new resettlement plan;
(5)
Long land acquisition cycle;
(6)
Misguided by misconceptions, lenders are generally indifferent to project financing;
(7)
It is difficult to carry out work in remote areas;
(8)
Time-consuming civil disputes account for a considerable proportion in hydropower project construction;
(9)
Protection or migration of special geological structures and cultural relics;
( 10)
Research, development and procurement of construction equipment.
However, making and implementing a reasonable work plan can greatly shorten the design cycle. With the help of satellites and other modern measuring equipment
Preparation, topographic survey and data collection time can also be greatly shortened.
2
.
seven
Submerged area
In fact, only multi-objective comprehensive utilization water storage reservoirs have a large submerged area, and such reservoirs are being refined.
Study on technology, hydrology, ecology and environment before construction. Therefore, people think that small reservoirs should be built as much as possible under any circumstances, and they
It is believed that as long as the high dam is changed into a low dam, the submerged area of hydropower projects will be reduced. Small radial hydropower stations will replace large hydropower stations.
A question that many people argue about. It is found that even in the plain area like Gujarat, the submerged area per unit storage capacity of high dams is larger than that of medium dams.
Dams are much smaller, even smaller in hilly areas.
2
.
eight
ecological environment
In India, the main reasons for forest reduction are the use of trees as fuel and building materials, overgrazing, deforestation and farmland reclamation.
Although the forest reduction caused by hydropower development in the valley area can be ignored, the construction authority of hydropower projects is still fundamental.
1980
Shelterbelt was promulgated in 1998.
Forest law compensates according to high standards. More and more people are worried about the impact of reservoir floods on animal and plant communities and the extinction of rare species. water
The construction of the dam may affect some dried fish, but at the same time, it can be released because of the long-term immersion of the surrounding vegetation and soil by the reservoir during the water storage period.
Putting in a lot of nutrients will greatly increase the number of other fish, and migratory fish can survive and multiply in the upstream and downstream through fishways.
An increase in fish has been observed in many reservoirs. Although the forest area is reduced due to the flood of the reservoir, it is necessary to see this through the construction of the reservoir.
Turning the wasteland into farmland, it is lush and full of vitality.
conclusion
The benefits of dam construction vary. As far as power generation is concerned, dam power generation has gradually become one of the main sources of electricity, which has greatly eased.
We have solved the problem of power shortage in China and solved the basic electricity consumption for industry and life. We are all beneficiaries. Imagine, if there is not enough electricity supply, industry
When production stopped and the light dimmed, didn't people's quality of life greatly decrease? Think about how terrible it is to have no electricity. Building a dam has enhanced mankind's understanding of the big.
The control ability of rivers can make better comprehensive utilization of water resources.
As for the opposition saying that dams affect biodiversity, force migrants and breed corruption, we can't generalize.
Generally speaking, they are all built.
Directly caused by the dam. First of all, even if the dam is not built, other human activities will have an impact on the environment, and the original species will also change due to the change of living conditions.
It is a natural law, not the fault of dam construction. Secondly, immigration will not harm the interests of the people in the reservoir area, because most dam sites are built.
In the mountainous areas, people there used to live in poverty. If they move, the government will compensate them. They are usually willing to take this opportunity to get rid of poverty.
Living environment, not coercion. For example, the number of immigrants from the Three Gorges Project in China has reached.
1 10
Million, ranking first in the world. However, by developing the implementation of immigration
After that, people's lives became more stable and many people became rich. This is a successful case. Third, there are indeed people who seek personal gain in the name of building dams.
Those moths driven by greed, if they don't build dams, will also use the name of building roads, bridges and Gai Lou to harm the public and enrich the private interests. The fundamental solution to this problem is
Control corruption, not stop building dams.
In a word, from the current social demand, appropriate dam construction is in line with the sustainable development of resources and environment. As far as specific projects are concerned, it should be
Dialectical analysis of the two places, we must make rational decisions according to the national conditions and needs: dam projects with more advantages than disadvantages can improve the environment and benefit.
People should actively build dam projects that have a great impact on the environment and also have great social benefits, and various measures should be taken to minimize them.
Adverse effects, allowing it to be launched will leave a huge negative impact on the dam project, leaving the problems that are temporarily difficult to solve for future generations to develop. Anyway,
We should cherish and make full and rational use of biological resources endowed by nature, solve the disadvantages of dams one by one and give full play to their advantages.
Give full play to the extreme, make full use of the comprehensive benefits brought by the dam, promote sustainable economic development and benefit the people.