News detail
  • 【Attents:0   favorite:0   Review:0】
  • present status of water conservancy in China
    publish time2014-04-15

    China is an agricultural country in the past , due to the frequent floods and droughts , water conservancy in China occupies an important position in particular , water conservancy regarded as rulers of the country and bringing peace event . Ancient water conservancy in China has had a glorious history, but due to the long feudal rule , water development retardation. After the Opium War in 1840 , China frequent wars, water conservancy construction stalled . Until 1930 , it built a number of modern water conservancy projects. During the Japanese invasion of China , not only did the development of water conservancy , original works also more disrepair. Establishment of People's Republic of China on the eve of flood control embankments only 42,000 km, and more incomplete, low flood control capacity ; capacity of over 100 million m of large reservoirs six medium-sized reservoirs over 10 million m of 17 , and a small number of small reservoirs and embankments ; irrigated area of ??2.4 million acres , the lower level of assurance ; electromechanical irrigation , hydroelectric few. Until the establishment of the People's Republic of China , the rapid development of water utilities only .

    China's total water resources in water resources development is about 2.81 trillion m, where runoff is about 2.71 trillion m, ranking sixth in the world . But lower per capita , 1988 to 2474m, the world's per capita consumption of only quite 1/4 . China 's annual precipitation and river runoff in the spatial and temporal distribution is very uneven . Southern , less north ; annual rainfall concentrated in the flood season , big changes between years , even the abundance , even dry year often.
    The early 1980s China , the country has the largest supply capacity of water conservancy facilities over 470 billion m, accounting for 16.8 percent of total water resources , including the amount of runoff exploitation over 410 billion m; accounted for 15.3% of river runoff ; groundwater extraction volume is 59 billion m, shallow groundwater utilization rate of 31.5% . The country's total water consumption ( not including Taiwan , the same below ) of more than 440 billion m, which accounted for 88% of agricultural water , mining and industrial water use accounted for 10.5% , accounting for 1.5% of urban domestic water . The average annual per capita water consumption is 460m, more than half of the world average per capita water consumption slightly .
    The degree of development and utilization of water resources in China in the region is very uneven. Each lower South River , were 17% below the lowest Southwest , less than 1%. North to develop a higher degree of utilization of rivers , the Haihe River has reached 67.7% , up 54.8% in the Huaihe River , Yellow River reached 42.8% . Exploitation of the country , mainly in the northern plains of groundwater area, plain area of Haihe River Basin groundwater exploitation rate has reached 84.4 percent , up to 53.4% ??of the Yellow River , Huaihe River Basin of 40.1 %. Some areas due to over-exploitation of groundwater , groundwater depression cone formation , and even cause land subsidence . Coastal areas also appear localized seawater intrusion phenomenon .
    Due to lack of water resources in the north , since the 1970s , many regions and some coastal cities have water crisis have appeared , such as the Beijing-Tianjin -Tangshan region , Shanxi energy base , Liaohe River region , as well as some coastal cities in Hebei Plain , water supply and demand are very outstanding. In order to ease tensions in the region with water , in addition to taking water conservation, arrange and foreign industrial and agricultural water projects some temporary emergency measures , but also continue to build a number of inter-basin water transfer project , such as lead Luan , Luan River Don , cited Pitt ( river ) into a large ( even ) , Yellow River to Qingdao ( Island ) and other projects, but far from reversing the region's water shortage situation radically.
    There are a number of water resources development and utilization of the following problems: ① With the growing population, sustainable development of the national economy, and the continuous improvement of people 's living standards , the demand for water will increase significantly . For northern drylands , supply and demand will become more serious. ② water departments , there are still different levels of waste , agricultural waste water especially serious , most of the irrigation canal seepage no facilities , there are a considerable part of the irrigated supporting insufficiency , a large leakage losses, the effective use of general canal coefficient of only 0.4 to 0.5 ; industrial water reuse rate is low , generally around only 30 %. Urban living and environmental water saving potential is great. ③ China since the 1970s emphasis on water conservation, but far from the national water pollution control , waste water discharge to waters is increasing year by year. 1988 amounted to 36.2 billion national sewerage t, about 74% of waste water is discharged directly into waters without treatment , some cities along the river downstream has significant contamination zone. Since the 1980s , the rapid development of township enterprises , more so the further expansion of water pollution , both exacerbated the supply and demand of water resources , but also endanger the health of the people . ④ Some hydraulic engineering, water resources utilization due to insufficient attention on the shipping , fisheries , environment , etc. had some adverse effects .
    Water resources development and utilization trends : ① the implementation of water conservation. Agriculture is the major water users , water has great potential , and actively implement various water-saving measures is inevitable. Mainly to improve industrial water reuse ; in dry areas are generally restrict water consumption for industrial development. Urban living and environmental water , requires the use of water-saving devices , setting waterways, use of recycled water. ② increase in water source projects . Construction of medium-sized reservoirs , increasing runoff storage capacity , improve the utilization of river water . ③ research and implementation of inter-basin water transfer project . There are plans to solve the problem of water shortage in northern and coastal cities . ④ strengthen the protection of water resources. Implemented to prevent the main principle of combining prevention , strengthen water management, construction of sewage treatment facilities , control of the city , factory effluent discharge standards. ⑤ and consider requirements for water sector , utilization of water conservancy construction , and strive to a water use , comprehensive benefits of a project , so that water resources are fully utilized. Try to avoid adverse effects on shipping , fisheries , environment and so on.
    China is one of the National Flood Flood frequent . Chinese population , industry is mainly concentrated in the lower reaches of the seven rivers and coastal plains region , an area of ??about 740,000 km, population and industrial and agricultural output accounted for 40% and 60 % of the country respectively , are the most fertile regions in China . The flood level in the following areas and more , rely on dikes to protect , often under serious threat of flooding .
    After the founding of People's Republic of China , namely the original recovery and strengthening of flood control projects . 1950 began on a comprehensive governance Huaihe , and then on the Yangtze River, Yellow River, Haihe River and other major rivers begin a planned and systematic management. To the end of 1988 , the country has built a large reservoir 355 , a large sluice 300 , the new reinforced embankments 200,000 km, to provide more of the Huaihe River, Haihe River outfall tunnel into that Huaihe River drainage capacity expanded from 8000m / s to 13000 m / s, Haihe River drainage capacity expanded from 2400m / s to 20000m / s or more, but also opened up a number of detention areas . The major rivers has formed a relatively complete low standard of flood protection system.
    Since the 1980s, all the major rivers and flood control standards : the Yellow River is about 60 -year return , the Huaihe River is 50 years , Haihe River is 50 years , the Yangtze River , Pearl River, Songhua River , Liaohe River, Sea Hebei Department about 10 to 20 -year return . National flood control task of the city, in addition to Beijing , Shanghai , Shenyang, Changchun , Harbin, Guangzhou and other cities to reach more than 100 years of flood control standard , the other urban flood control standards are very low .
    China always attaches importance to flood control work , the basic principle is " safety first, prevention, prevention is more important than rush , be prepared ." In addition, since the 1950s, on the use of flood forecasting, flood warnings and other non-engineering flood control measures for reducing flood damage and achieved remarkable results. 40 years, China has accumulated short-term flood forecasting a relatively mature experience , flood control scheduling work has gradually improved . In order to accelerate the transmission of information to improve forecast accuracy , growth forecast period , from the late 1970s onwards, a number of important river in large rivers , it is important to establish the reservoir tributaries automated forecasting system , an online real-time flood forecasting .
    Flood trends : ① China 's flood control task is arduous , and flood control projects tend to be expensive. Flood protection measures in order to make economically rational , and with affordability countries to adapt, and to reduce flood damage as much as possible , the use of engineering and non-engineering measures combining is necessary. The main engineering measures is to continue heightening reinforced embankments , river training and building of detention basin , handle dangerous reservoirs , combined utilization, flood control engineering construction necessary ; non-engineering measures are to enhance the planning and construction of prediction system , good lag security building flood storage area and production structure necessary reforms, in particular to strengthen the stagnation of population control flood zones, land use and management. ② With the development of urbanization , urban flood control increasingly important . Local conditions to improve the city's flood control standards become imperative. In case of extreme flood , there should be very countermeasures. ③ With the development of science and technology, flood forecasting, alert , monitoring will have a big development .
    Irrigation and drainage China is characterized by a large population, limited arable land , limited to reclaim wasteland , a way to solve mainly by improving agricultural yield per unit area . Because natural rainfall unevenly distributed in space and time , often do not dry farmland that floods, agricultural production is very unstable . Improve the yield per unit area , you first need to develop irrigation .
    Since 1949 , China 's irrigation and drainage development soon . To the end of 1988 , the national development of irrigated area from 2.4 million hectares to 7.2 million hectares , ranking first in the world . Waterlogging area reached 2.85 million hectares , accounting for 78% of the waterlogged area ; saline improved area of ??over 7200 acres , 63% of salinization of arable land . China in less than half of the country 's irrigated arable land , the national grain production 2/3 of the basic problems of poverty 1.1 billion population, plays a decisive role . Famous Dujiangyan Irrigation , conducted since 1949 renovation and expansion , the development of irrigated area from 288 acres to 1,100 acres ; newly developed in 1949 in Anhui Pishihang Irrigation , design irrigation area 1026 acres, 1985 effective irrigation area of ??826 mu. Jiangsu Jiangdu pump stations , is currently China 's largest pumping irrigation works , installed 49800kW, pumping capacity up to 473m / s, to the region and the Yangtze River water to Xuhuai Lianyungang City , but also to solve the majority of the region and in northern Jiangsu along the canal drainage problems , and both shipping, urban water supply and industrial water supply benefits.
    China in the development of irrigation , but also according to local conditions for the comprehensive management of droughts and stains alkali , alkali such as droughts and comprehensive management of the North China Plain , Jiangsu Lixiahe droughts stains governance , have been successful experience. Irrigation water in the settlement , China since the 1950s , on the use of lead storage mentioning combined and noted the joint use of various sources of water , water storage ponds have included the main source of water in many areas ( such as reservoirs or water ) Engineering and Irrigation works combine well irrigation canal irrigation and combine not only improve the irrigation level of assurance , but also conducive to maintaining irrigated groundwater level , prevent soil salinization .
    The main problem facing China Irrigation : Irrigation and drainage systems have become not perfect , channel utilization factor is low, the amount of water wastage ; engineering aging facilities in disrepair , effective attenuation. Due to limitations of land and water resources, natural conditions and economic conditions , the development of new irrigation projects more difficult. Therefore , the future development of the irrigated area may be limited.
    To meet the needs of the people and national economic development, irrigation and drainage development trends are: ① rely mainly on the implementation of the technological transformation of existing irrigated , water-saving , energy -saving arable land , soil , reduce operating costs , such as the main objective . Consolidate the improvement of existing irrigation area , improve water quality. Existing irrigation and drainage area to become sustainable high and stable yield of grain and cash crops production base. ② conducted on the low-yielding farmland drought or drought stains comprehensive management base in order to increase agricultural production and improve economic efficiency. ③ In dry areas , the agricultural structure adjustment necessary to limit water consumption of rice planting area , research and promotion of water-saving agriculture and rainfed agriculture . ④ strengthen land management to prevent arable land and irrigation facilities have been destroyed farmland occupied, maintained without reducing the irrigated area , and can be appropriately expanded . ⑤ combine agricultural technology to increase food production per unit area, in order to meet the needs of the community for food .
    Theoretical potential for hydropower hydropower China 676 million kW, which may be developed installed capacity of 378 million kW, annual generation capacity of 1.92 trillion kW · h, ranking first in the world . Although China is rich hydropower resources , but uneven geographical distribution . In exploitable hydropower resources in the northeast , north, east three regions accounted for only 6.8% , and South Africa region accounted for 15.5% , 9.9% Northwest , Southwest region accounted for 67.8% . Large hydroelectric power plants are concentrated in four provinces in the southwest .
    Your view:
    Verify code:

    亚洲 欧美 国产 综合-aV欧美国产在线-久久国产自偷拍^& <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <蜘蛛词>| <文本链> <文本链> <文本链> <文本链> <文本链> <文本链>