CONSTRAINING FACTORS TO SUSTAINABLE UTILIZATION OF WATER RESOURCES AND THEIR COUNTERMEASURES IN CHIN

CHINESE GEOGRAPHICAL SCIENCEVolume 13. Number 4, pp.310-316. 2003Science Press, Bcijing. ChinaCONSTRAINING FACTORS TO SUSTAINABLEUTILIZATION OF WATER RESOURCES ANDTHEIR COUNTERMEASURES IN CHINAZHAI Jin-liang', FENG Ren-guo', XIA Jun2(1. Bureau of Science and Technnlngy for Resources and Environment, Chinese Acadery of Seiences,Reijing 100864,P. R. China; 2. Institute of Geographic Sciences and Natural Resoures Research,Chinese Academy of Sciences, Beijing 100101, P. R. China)ABSTRACT: This paper discusses the constraining factors to sustainable utilization of water resources in China, andthe countermeasures to rcalize sustainable water utilization. The result of comprehensive analysis shows that con.straining factors to sustainablc uilization of water resources in China are complicated, including physical geographi-cal factors and socio-economic factors, such as uneven distribution of water resources at temporal and spatial scales,inappropriate intional arangement and non-waler saving and non-water-conservation production and life mode.The countermeasures against constraining factors to water resources sustainable development are put forward as fol-lows: 1) using wetlands and forests, and through spatial conversion to realize temporally sustainable supply of waterresources; 2) transferring water between busins and areas and developing various water resources in water shoragearca: 3) establishing water-saving socity, 4) strenghening water pollution control and water resources protection; .and 5) establishing unifed waler resources management mechanism.KEY WORDS: water resources; sustainable utilization; ChinaCLC number: P968Document code: AArticle ID: 1002-0063(2003)04-03 10-07Water resources are essential and indispensable for base for the reasonable utilization of water resourcessustaining biologic lives and supporting social and e-and is beneficial for the socio-economic sustainableconomic development, and sustainable utilization of development.water resources is vital to human existence and So-cio-economic sustainable development. Although wa-l CONSTRAINING FACTORS TO' WATER RE-ter resources are relatively plentiful in China，with aSOURCES UTILIZATION IN CHINAtotal amout of 2.8124x 104m)，the per capita averagewater resources are only 2500m'、which accounts for 1.1 Uneven Distribution of Water Resources at Tem-1/4 of the world average level (DENGel al, 2002). poral ScaleWith the rapid population growth and socio-economicdevelopment in China，the demand for water is in-Physical geographic conditions of China result in quitecreasing and water resources are under mounting pres-uneven distribution of water resources over the coun-sure， and the exploitation and utilization of water re-try at temporal scale. The country lies in the east ofsources is becoming unsustainable. Constraining fac-the Eurasia Continent, and it covers a vast territorytors to sustainable utilization of water resources in with varied topographic and diverse physical features,China are complicated,including physical and geo-including complex climates. The southeastem part ofgraphic factors and socio-economic factors. To com-the country is affected by the southeastern monsoon ofprehensively analyze these constraining factors anthe Pacific Ocean and its southwesterm part is influ-give their countermeasures can provide a scientificenced by the southwesterm monsoon of the Indian 0-Received date: 2003-06-18Foundation item: Under the auspices of the Knowledge Innovation Pro中国煤化工xKZX2.sW.317)Biography: ZHAI Jin-liang (1975- ), malc, a native of Shandong Pro:MYHCNMHGsoil resources andcnvironmental researchConstraining Factors 10 Sustainable Utilization of Water Resources and Their Countermeasures in China311cean. Influenced by monsoon and continental climates, controlling flood through building levees and dams isprecipitation in the northern China tremendously varies the major theme of river management in China. In thewith a change rate of 15%-30%. Precipitation in sum- country， cognition about flood is almost entirely bi-mer (June, July and August) accounts for 60% of total ased on its socio economic calamitous effects, andannual precipitation and from May to October the pre- flood is generally viewed as disaster,calamity andcipitation constitutes about 80% of total annual precipi- even evil. However, flood is intrinsically a kind oftation，thus floods tend to be in summer and droughts water resources and flooding is a form of water re-are likely to occur in other seasons. Continuous sources reallocation and it plays a significant role indry-years phenomenon appeared in all main river balancing and modifying the distribution of water re-basins in China such as the Songhua River Basin in sources especially at time scale (ZHAI et al, 2000).Northeast China, wherc once dry period lasted for 7 Natural flood is extremely constrained within riveryears continually with extremely less precipitation. The channels because the flood management strategytemporally uneven distribution of water resources due stresses more drainage than storage and the generalto physical geographic restrictions makes it very diffi- guideline of flood management is anti-flooding, thuscult to sustainably exploit and utilize water resources.plenty of flood water resources are not intercepted byUnreasonable exploitation of flooplains especially floodplain wetlands and forests, on the contrary, theydeforestation and encroachment of wetlands intensi- are drained and wasted in the rain season and after thefied the uneven distribution of water resources tempo- rain season there is severe water shortage.rally. More than 90% of cities are located in and about600x 10* people live in floodplain areas in China. The 1.2 Uneven Spatial Distribution of Water Resourceslatest census statistics show that in floodplain areas and Water Shortage Especially in the northem Chinathere are 300 -500 persons/km? with the highest as1000 personskm? and population in floodplain areas Due to physical geographic conditions, the easterm andare rising (Nanjing Institute of Hydrology and Water southwestem parts of China are moist and have rela-Resources, Office of State Flood Control and Drought tively plenty of precipitation，while the northwestermRelief Headquarters, 1997). Due to over lumbering part of the country extends into the deep inland of theand less afforestation stimulated by economic profits，Eurasian Continent and is quite arid with lttle precipi-forest coverage in the upper reaches of main rivers tation. To the north part of the Changjiang River, withand floodplains in China dwindled severely，and tak- an area accounting for 64% of China, water resourcesing the Changjiang (Yangtze) River as an example，takes only 20% of the whole country (FENG, 2000).forest coverage in the upper reaches diminished from Only 10% of China's groundwater lie under one-quar-50% before the l3th century to 22% in the 1950s and ter of the country's cultivated land, which is located into about 10% at present. Excessive exploitation and Beijing and Tianjin municipalities, and Hebei, Shanceaseless encroachment of the naturally flood 0occu-dong and Henan Provinces. Water resources per capitapied the areas under the pressure of population growth in China only accounts for one fourth of the world'sand agriculture and industry development, especially average level, and in the Huanghe (Yellow) Riverblind reclamations from riverside wetlands resulted in basin， the Huaihe River basin and the Haihe Riverloss or shrinkage of the floodplain wetlands, reduction basin in the norther China water resources per capitaof the cross section of river course and the flow in- is only one fith of the country's mean level and watercreasing of flood stage in rivers, thus water storage ca- sbortage has constricted socio-economic developmentpacity of basins was lessened. In the middle and lower in those areas severely.At present,annual waterreaches of the Changjiang River, more than 800 000ha shorage is 21.8 x10*m3 in China and 18.1 x102m’inof floodplains have been reclaimed and changed into the northem China. Annual economic losses due tofarmlands and industrial areas in the past half century, water shortages in the northern China amount to moreand 82% of the seasonal inundation floodplains com- than 120x109 yuan (RMB) (about US$14.5 billion)pletely lost (CHEN and CHANG, 1995). The capacity each year. About 27x10ha of farmland are hit byof water interception and storage by forests and wet- drought each_ year countrywide and there arelands was severely decreased and rainfall was not suf- 30 |中国煤化Iirrigation annually.ficiently regulated by forests and wetlands before and Mo_ries are confrontingafler the flood period. In order to protect life and e-watHc N M H Geriously thre aedconomy from damage caused by flood, preventing and by water shortage and in urban areas the annual water312ZHAI Jinliang. FENG Ren-gpuo, XIA Junshortage is 6x l09m’in tbe country.[n drought years.1.5 x10° persons in China， compared with 1 sewagesuch as in 2000， water rationing was adopted for treatment plant per 5x 103 persons in developed coun-dwellers in cities such as Tianjin,and in cities oftries. About 41.6x10*m3 of waste water and sewageHarbin, Changchun, Tianjin and so on public baths, car are discharged by municipalities and industry eachwashing were limited even closed for saving water. In year, among them 95.5% of the municipal sewage andrural areas, it is very dificult for 65x 10* persons and83% of the industrial wastewater are discharged into60x 10* domestic animals to get drinking water. Waterrivers and nearby water bodies or used as irigationshortage has been "the neck of bottle" for sustainablewater without any treatment. According to the Bulletinsocial and cconomic development in China.of Chinese Environment Status Quo in 2000 by theStatc Environmental Protection Administration 01.3 Tremendous Water Resources WasteChina，seven major rivers are all polluted to variousdegrees and organic contamination is serious in rivers.In China, there is a phenomenon of the coexistence ofLakes are losing and the remaining parts are eutroph-serious water shortage and severe water waste. Irriga- ic. Over extraction of groundwater in a plunderoustion consumes over 70% of total water supply in Chinaway in the northern China has produced depressionbut the rrigation efficiency is very low in the country. cones in aquifers. Depression cones in the deepOf China's existing 130x 10*ha of cutivated land, 40%aquifers in Heibei Province， the north of Henanare irigated, but of which only 5% have adopted mod-Province and the northwest of Shandong Provinceem water-saving irigation techniques such as sprayhave linked together and formed an area of overand drip irrigation. In most of the irigation areas, the40x10km2 with depression cones in the northern Chi-irrigation method is to lct the water flow freely all over na, including Bejjing, the capital of China, and Tian-the piece of land until it is covered with a certain depthjin, one of the municipalties directly under the juris-of water. Because of poor ditches and antiquatcd and diction of the central govermment (The State Environ-outdated irigation facilities， irrigation water is seri- mental Protection Administration of China，2001).ously lost through cvaporation, leakage and deepWithin the extremely over- extracting areas, land sub-drainage and the result is that only about 40% of the sidence and seawater intrusion and other environmen-country's irigation water is used effectively. Takingtal problems has been induced. For instance, the cen-the Huanghe River basin as an example, about 90%of tral area of Tianjin has subsided by 2.6m since thethe water resources there are used for irigation but the1960s. From inland rivers, lakes and reservoirs to ma-irrigation efficiency is very low，and only about 30% rine water areas, the overall water eco-environmentof the irmigated water is used efctively. Besides agri- has been widely polluted and destructed.culture, expanding industrial sector needs a largerWidespread contamination of surface waters by in-amount of water resourccs and the water use efficiency dustrial wastewater and inappropriate application ofin industries is 75%，being lower than that of devel- pesticides and chemical fertilizers in farmland resultedoped countries. Water leaking in the municipal water in regional disease such as gastric ilhess and cancers,supply system is very serious, and more than 20%of and the yearly discharge of 30x104t of sewage. ofthe water is leaked out in most of the cities. Welfarewhich only 2.7% were treated, resulted in 1.5 x106water resources allocation system formed under thecases of acute schistosome infections every year. Theplanned economy makes agricultural and industrialloss of yield of fresh water fish due to water ecosys-and other water users have lttle incentive to invest in tem destruction amounted to 80 x10t yearly. Thewater recycle and wastewater treatment because theyavailable water resources reserve for development andreceive lttle benefts for doing so，and at current low utilization via engineering measures has been obvious-price levels, people tend to care lttle about wasting ly polluted, reduced and heavily damaged. The quanti-water and concerm lttle about the govemment's advo-ty，quality and availability of clean water resourcescacy of water conservation and water saving.have been severely changed. Water pollution and de-structive exploitation of groundwater have worsened1.4 Water Shortage Aggravated by Water Pollution the eco- environment quality， aggravated the contra-and Destructive Use of Water Resourcesdiction between water demand and supply thus inten-shortage crisis irIndustrial waste water and urban sewage treatment(中国煤化工rate is low，with only 1 sewage treatment plant per:TYHCNMHGConstraining Factors to Sustainable Ltilization of Water Resources and Their Countermeasures in China3131.5 Lack of Unified and Integrated Water Resources runoff through water interception by canopies, trunksManagement Mechanismand branches and infiltration into forest soils duringflooding period and give them back into rivers afterIn Chinese folklore, dragon in the heaven was respon- flooding. Water storage of forest can reach 50x 10sible for water resources management. Now， in the m' /km2 to 200x 10^m/km', and flood runoff can be re-country, there are too many agencies and govemmentsduced 70%-95% in forest stands. In China, rainfallgiving approval to water management and this phe- water resources caught by forest crown can reachnomenon is called "multi-dragons manage water" in134-626mm and the average precipitation interceptionChina. Ministries of the P. R. China, including Min- rate by forest crown is 21.6% (L, 1999). During theistry of Water Resources, Ministry of Construction, periods of flooding over banks, wetlands act as spon-Ministry of Agriculture, Ministry of Transportation，ges soaking, absorbing and holding water, and afterMinitry of Land and Resources, National Develop- the flooding pcriod, wetlands gradually release thement and Reform Commission, and the State Envi-water they stored into river again. So, in flooding peri-ronmental Protection Administration et al., all havc od wctlands and forests can reduce flood peak runoffsome responsibilities for water resources management. and reduce the flood discharge, thus suspend the com-There are corresponding affiliated departments and ing of flooding peak and store water resources, and inbureaus to each of the above management sectors in low-water season, they can significantly enhance thegovenments at all levels such as provincial, prefec- runoff in rivers by recharging water stored in floodingtural and county. All of the minitries and administra- period, thus low-water period of rivers is shortenedtions have some management authorities, for instan- and water resources are relatively evenly distributed inces，approval to water source engineering rests with rivers at temporal scale (DENG el al, 2000). Unrea-the Ministry of Water Resources and its afiliated de- sonable deforestation and excessive encroachment ofpartments and bureaus, and water supplying rests with wetlands in China especially in environmentally vul-the Ministry of Construction and its affiliated depart- nerable areas have brought about increased soil ero-ments and bureaus, and water pollution control rests sion and hydrological regime negative changes ofwith the State Environmental Protection Administra- rivers as demonstrated in the 1998 flooding in thetion and its afiliated bureaus. Exploilation of surface Changjiang River basin, the Songhua River basin andwater and groundwater is separately managed by dif- the Nenjiang River basin. Effective measures such asferent agencies. There are short of efficient and suffi- establishing more wetland and forest natural reservescient co-operations between different agencies in wa- must be taken to protect forests and wetlands fom be-ter resources management as the management sectors ing further damaged, and related projects such as thestrengthen their own benefits as they take part in the project of Natural Forest Protection and the project ofmanagement affairs. There are river basin commiss Turming Farmland into Forests and Wetlands shouldions affiliated to the Ministry of Water Resources in be promoted. In the upper reaches of the Changjiangmain river basins in China，but their responsibilities River and in the upper and middle reaches of theand accountabilities are not definite and their roles in Huanghe River, remaining natural forests should bebasin and water resources integrated management are strictly prohibited from lumbering. Frequently inun-constrained.dated wetlands by floods should be prevented frombeing reclaimed. We recommend that all the hillsides2 COUNTERMEASURES AGAINST CONSTRAIN- above 25° in slope degree with forests and all theING FACTORS TO WATER RESOURCES SUS- wetlands within 10-year inundation frequency flood-TAINABLE DEVELOPMENTplains should be prohibited from being further re-claimed and developed, and in environmentally fragile2.1 Using Wetlands and Forests or Other Methods, areas they should be closed and used as natural regula-and Through Spatial Conversion to Realize Temporal- tors for runoff and water resources even distribution atly Sustainable Supply of Water Resourcestime scale.Besides using wetlands and forests to storc rainwa-Wetlands and forests serve as natural regulators of ter and through spatial conversion to regulate riverfloods in river basins as they intercept rainfall or give”used according to I0o-places for runof" from precipitation to be stored and ca中国煤化工and the measures .also supply water for rivers. Forest can regulate river shor!YHC N M H Glocal conditions. In314ZHA1 Jin-liang, FENG Ren-guo, XIA Junsome areas the northwestemn China，people dig kariz,plan of the country. There are some other water trans-water cellars and vaults, water pools and ponds infer projects carried out or being implemented such astheir courtyard or on their fields on the slope sponta-the project of Transferring the Songhua River' s waterneously to store the rainwater. They use the stored to Changchun City，the project of Transferring therainwater both for drinking and for irigation after theYingna River' s water to Dalian City and so on. Theseprecipitation period. Through these approaches thprojects play significant roles in supplying water forrainwater is distributed evenly the year round and usedmunicipal and industrial demand and relieving thmore efficiently. The 121 Rainwater Collection Pro-constraint of water shortage to social and economicjects in Gansu Province, the 112 Rainwater Collection activities in the water receiving cities and areas.and Water-saving Irigation Projects in Inner Mongoli-Besides receiving transferred water resources, ina Autonomous Region, and Rainwater Collcction by water shortage areas especially in coastal areas，sea-Vaults and Water-saving Irigation Project in Hui Au-water should be developed. China has 4.73x l0*km2 oftonomous Region of Ningxia have gained efficient e- sea area on the middle part of the West Pacific coastco-environmental and socio-economic benefits. Thro-and a long coastal line in its east and southeast. Uti-ugh the spatial patterm exchange of water resourceslization of seawater including directly using seawatercomparatively sustainable distribution can be available and seawater desalination is an important pass to miti-in the temporal pattern.gate fresh water shortage in coastal cities and areas. InChina now，seawater is mainly used for cooling ec-2.2 Transferring Water between Basins and Areas andtric and chemical industries and the use of freshenedDeveloping Various Water Rcsources in Water Short- seawater is far more bchind because of lagging of re-age Areaslated technology development. Advanced technologyand methods should be studied, developed and appliedWater resources shortfall would continue to increase to seawater desalination or seawater direct utilization.even to unbearable levels with the further social and e-Besides developing and utilizing seawater, technologyconomic development in North China since water re-research and application of light saline water in iriga-sources in this area have been tapped rather suficient- tion or municipality using should also be promoted toly and there is less potential to further increase locallyreduce the pressure upon freshwater resources.available water supply. According to the Ministry ofScience and Technology，80% of water resources in 2.3 Establishing Water-saving SocietyNorth China have already been exploited and the re-maining parts are all too expensive to be developed.Regional socio-economic development plan should beWater saving and water tapping measurcs can not in accordance with the loading capacity of water re-thoroughly resolve the water resources shortage prob- sources and should include water resources develop-lem and change the situation of the deteriorating ofment plan as one part of it. Agricultural, industrial,water eco-environment in North China. The South- municipal and domestic water consumption should allNorth Water Transfer Projecl, which transfers waterbe on the basis of water saving.It is very signifcantresources of the Changjiang River Basin to the to develop water-saving irigation and water-saving a-Huanghe River Basin, the Huaihe River Basin and thegriculture management since agriculure is the largestHaihe River Basin, is necessary to be carried out. The consumer of water resources in China. According toSouth-North Water Transfer Project, which would be the basic economic and technologic conditions of agri-the largest water transfer project ever, has drawnculture in China, the technology of plugging channelbroad discussions in academia of different back- leaks or using low-pressure pipes instead of channelsgrounds such as economy, ecology, geography and soto reduce water leakage，evaporation and infiltrationon. Although there still has disputation evcn contro- must be promoted and developed, and to adopt sprayversy about the project， now a consensus is emerging or drip irigation technology in the areas with the ap-in China that the Central and Eastem Routes of the propriatc economic and technological conditions. Beproject should be built as quickly as possible and this sides water saving irigation, effective technologicalhas been backed up by Chinese government as themeasures should be taken to develop water-saving a-project has been listed as one of the four most impor- griq中国煤化士ding selecion oftant projects during the "the 10th Five-year Plan"，drolvation of soil mois-which is the basic social and economic development ture:YHC N M H Govering, reasonableConstraining Factors to Sustainable Uilization of Water Resources and Their Countermeasures in China15utilization of chemical agent for moisture preservation change their products. To municipal sewage pollution,and so on. To industrial water using, efforts should be one of the significant countermeasures we recommendmade to raise the efficiency of the industrial water is that detergent with phosphorus should be prohibitedconsumption and lessen water consumption by adjust- throughout China by administration rules to relieveing and optimizing the industrial structures, adopting eutrophication of water bodies.the water-saving technology, limiting the highly waterTo areas where groundwater is destructive, ground-consuming productions, raising up the ratio of the newwater protection areas should be defined and rainwa-technological industries which has less water demand. ter should be used efficiently to replenish naturalTo domestic and municipal water supply and con-aquifers and resume the groundwater ecosystem balsumption，water supply plan should be scientifically ance to gradually realize the benign cycle of water re-made and management should be strengthened, and sources, and technological standards pertaining l0 theefforts should be made to improve efficiency of watercontrol of groundwater pollution should be set up. Indelivery by reducing the seepage loss in the running water conservation and pollution control of surfacewater conveyance pipes network. Public education and water and groundwater, it is important to enhance ex-professional training programs should be widely initi- amination of law enforcement and reinforce the legalated and strengthened to raise public awareness and supervision, and to promote public awareness and par-increase productive efficiency in water-saving. The es- ticipation.tablishment of water-saving society must be realizedvia multimeasures including administrative, economic,2.5 Establishing Unified Water Resources Manage-technical, legal and moral measures.ment Mechanism2.4 Strengthening Water Pollution Control and Water Lack of unifed and integrated management mecha-Resources Protectionnism has strictly constrained water resources sustain-able utilization in China. Appropriate instutional ar-Efforts should be made to prevent the deterioration of rangements with clear responibilities and accountabil-the aquatic eco-environment and realize the benign cy- ities are essential for water resources sustainable man-cle of water resources through strengthening water agement, and it is urgent to establish such unified wa-pollution control and water resources protection. lt is ter resources management institution through reform-necessary to set up an effective mechanism of support- ing the existing management mechanism. At the basining information for water pollution control and water scale, river basin commissions should be responsibleresources protection decision making through estab-for basin integrated management especially water allo-lishing an integral monitoring network of surface wa- cation to the provinces, autonomous regions and mu-ter and groundwater. To control agricultural pollution nicipalities, and in regions within river basin, onceto water resources, countermeasures should be taken, water allocation have been determined by the riverincluding improving farming techniques especially basin commissions， the detailed water allocation inabout reasonable fertilizer and pesticide using to re-different sectors such as agriculture, industry and mu-duce run-off of nitrogen and phosphorus, toxicants nicipality should be integratedly planned within ad-and harmful matters. To industrial pollution, total dis- ministrative districts. In China now, river basin com-charge amount of industrial wastewater contaminants missions are afiliated to the Ministry of Water Re-must be limited within the self-purification capacity of sources, sO, water resources management at both basinrivers and other water bodies. Countermeasures should scale and region scale can be systematically respondedbe taken, including promoting cleaner production and by the same series of agencies after the unified man-controling pollution throughout whole production pro-agement institution arrangement is completed. Unifiedcesses and strengthening pollution sources treatment and integrated management would be carried out toand reducing the generation and discharge quantity of realize reasonable control of over exploitation, har-pollutants. Investment in building treatment facilities nessing, conservation and uilization of surface waterand sewage plants for industrial wastewater and mu- and groundwater in both urban and rural regions,nicipal sewage treatment should be increased. Enter- which should rest with the Ministry of Water Reprises that bring out heavy pollution to water environ- sour中国煤化工-nts and prefecturalment should be imperatively ordered to close down,suspend operations, merge with other enterprises orMHC N M H Gnified institutional316ZHAI Jinliang, FENG Hen-guo, XIA Junmechanism, market-based water pricing regime should ing sociery and realization of sustainable water re-be scientifcally established and the key ofit is to raise sources uilization is a very complicated and systemat-the unrealistically low prices of water to approximate ic work involving the factors of population, resources,its true cconomic value. Welfare water allocation in environment, society, economy and so on. So, waterChina under the planned economic mode hinders the resources utilization must be in accordance with thefoster of water saving mechanism because water sav-development of population, resources, environment,ing cannot bring incorme to the executants and water society and economy together and follow the road ofallocation is determined by the govemment. It is nec- sustainable coordinated development， and definitelyessary to foster water entitlement market and institute this will be a gradual process, which needs long-terma system of tradable water entitlements subject to state efforts.supervision. Price hikes are effective measures toprompt improvements in water distribution efficiency,and also can produce revenue devoted to pay for wa-REFERENCESter-related investments and management. Laws andCHEN Yi-yu, CHANG Jan-bo, 1995. Wetlands loss and aler-regulations should be developed and formed as a com-ation of the floodplain in the lowcr and middle reaches ofplete set 1o guarantee unifed and integratcd water re-Yangtze River [A]. In: CHEN Yi-yu (cd.). Study of Wetlandssources management.in China [C]. Changchun; Jilin Sciences & TechnologyPress, 153- 160. (in Chincse)3 CONCLUSIONSDENG Wei, BAI Jun-hong, YAN Min hua, 2002. Problems andcounlermeasurcs of water resources for sustainable urilizationConstraining factors to sustainable water utilization inin China[J]. Chinese Greogrophical Seience. 12(4): 289 -293.China are very complicated, which include physicalDENG Wei, SONG Xin-shan, ZHAI Jin-liang. 2000. Wetlandprotection and sustainable utilization of water resources ingeographic factors and socio-economic factors. Physi-the fooded area [J]. Srience and Technology Resins, (3):cal geographic factors such as the uneven distribution58-60.