Scenario simulation of water security in China

Jourmal of Entironmental Sciences Vol. 16,No. 5,pp.765- -769 ,2004C11-26291XArticle ID: 1001-0742(2004)05-0765-05CLC number: Q149;X959 Document code: AScenario simulation of water security in China0UYANG Zhi-yun'，ZHAO Tong-qian'，WANG Ru-song' ，Leif S0DERLUND2，ZHANG Qiao-xian'(1. Research Centre for Eco- Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. E-mail: zyouyang @ mailrcees. ac .cn;2. Agifood Research Finland, Jokioinen 31600, Finland)Abstract: Limited water resources, increasing demand, low use eficiency, and serious pollution result in severewater resource dificult in China. The evaluation of addressing water problems and the search for effectivecountermeasures that ensure sustainable water use are key to China' s sustainable development. The “compoundwater security” consists of food security, lifte security， environmental security， and economic security. Byestablishing a conceptual model, the water security of China has been simulated in terms of four scenarios calledBAU( the business- as-usual scenario), TEC( the technology and economics scenario), IVL( the institution, values,and lifestyles scenario) and TSD( toward sustainable development) in this paper. The results indicated that watercrises, especially water shortages, are being experienced now and will continue to do so for a relatively long time inChina and that it is possible to reach a basic balance between supply and demand of water and grain under the TSDdeveloping pattern by a series of approaches including technological innovation, policy adjustments, and behaviourinducement.Keywords: water resource; water security; scenarios; simulation; Chinalow eco-awareness in policy making. Over the past 50 years，Introductionagricultural, industrial, and domestic water consumption hasWater scarcity has become a major threat to foodincreased 3, 46, and 41 times respctively( MWR, 2001).security，human health, economic development, and naturalUncontrolled water usage has led to a series of ecologicalecosystems on a global level ( Lubchenco，1998; Luijten ，problems in China such as rivers drying up, loss of wetlands2001 ; Vorismarty, 2000). Water security asessment is theand lakes, and the rapid decline of the groundwater table. Infoundation of water resource management. A great number ofaddition, .pollution is serious. In 2001， totalresearches on methodology and case studies have beenwastewater discharge in China was 42. 84 thousand millinreleased since the First World W ater Forum( Brown, 2002;tons, of which 53.15% was domestic sewage and 46.85 %Gleick, 2000; Luijten, 2001; Strzepek ，2000; Vorismarty,was industrial wastewater. The proportion of discharged2000). The basic method consists of modelling and scenarioindustrial wastewater that meets national quality standards wasanalyses, which can offer a way to consider the long- rangeup to 85.6%. But the proportion of urban domestic sewagefuture in light of uncertain factors and a way to examine thethat is treated is still only 36%. Most sewage is dischargedrequirements for a transition to sustainability ( Gallopin,directly into rivers and lakes without any proper treatment2000; Strzepek, 2000). This is usually viewed in a holistic( SEPA，2002 ). Limited waterresources, increasingmanner including water supplies and demands which comprisedemand, low use efficiency, and serious pollution result inits natural state and different forms of consumption such asserious water stress and make the situation of water securitydomestic，agricultural ，industrial，and environmentaldifficult .(Gleick, 2000; Rijsberman, 2000).A basic task for Chinese future development is meetingWater resource shortage and water pollution are widelyhe increasing water demand due to the fast social ancbelieved the most challenging issues in the futureeconomie development while protecting the water environmentdevelopment of China( World Bank, 1997; ESCAP, 1997;from degradation. Strategies for comprehensively balancingMWR，2001). Water resources per capita in China arewater supply and demand, as well as water use for societyestimated lo be only 2116 m' ，among the lowest in theand nature, are indispensable for the sustainable developmentworld. Meanwhile, the spatial and temporal distribution of of China. The evaluation of scientific mechanisms and ofwater resources is extraordinarily uneven: 83.8 % are locatedmethods for addressing water problems and the search forin the Yangtze River basin and its southern area. With theeffective countermeasures that ensure sustainable water usedevelopment of society and the economy, water demandsare key中国煤化工nent.increase rapidly due to such driving forces as high populationto simulate the watergrowth，rapid industrialization and urbanization, the strongsecurityfYHCN M H G dferet delpingdesire for a better quality of life，fragmented institutions, andpattems. The paper is organized as follows: In the nextFoundation item: The Knowledge Innowation Programme of the Chinese Academy of Sciences ( KZCX3-SW-424)。the SUSDEV-China Prjcet in the EU INCO-DEVProgramme( ICA4-CT 2002- 1004) , and the Studies of Harmonious Development between Water Conservancy and Natioral Economy(04-03-01)766OUYANG Zhi-yun et al .Vol. 16section, water security and its driving forces are introduced .rivers, lakes, and wetlands. Many of these changes will beSection 2 presents a conceptual model， scenarios andaccomplished through enforcement of regulations and throughsimulation methods. The results and conclusions archanges in awareness .presented in Section 3 and Section 4.2 System model and simulation methods1 Water security and its driving forces2.1 Conceptual model1.1 The concept of water securityBased on water security and driving force analyses, theThe concept of“compound water security" ( Wang,related quantified index and variables were defined. Then,1996) covers food security， life secunity， environmentalthe relationships between these variables were formulated andsecurity，and economic security. Food security meansa conceptual model constructed(Fig.1).providing enough water s0 that agriculture can satisfy theThe basic formulas are as fllows:growing population ' s increasing demand for food quantity,SW= WS.WD', WD = WDL+ WDA+ WDI, WDLquality, sufficiency， and accessibility. Life security means= N.μ°a+ N.(1-u).β,providing all citizens with sufficient clean water andWDA = A.γ.q，WDI = 1.λ， WS= WSS + WSGprotecting them from water-bome diseases and plague .+ WSR+ WSW+ WSD+ WST,Environmental security means maintaining the eco-integrity ofSG = GS.GD'the water eco-sphere ，including landscape, water, and soilin which SW is the index of water security in the target year;conserrvation， watershed management， and the balance ofWD and WS refer to the total water demand and the totalwater metabolism, to enbance the nature services so that theviability of the natural ecosystem is guaranteed andwater supply; WDL, WDA, and WDI are the domestic waterbiodiversity conserved. Economic security means raising thedemand，agricultural water demand, and industrial waterefficiency of walter use so that it can sustain stable growth ofdemand respectively; N， A，and GI are the totalthe national economy .population，farmland area, and gross industrial production in1.2 Driving forcesthe target year; μ，a，β，Y，q，and λ refer to theThe main driving forces of water security includeurbanization ratio, rural domestic water use，urban domesticpopulation growth， urbanization， economic development ，water use, imigated area ratio, irigated water quota, and thetechnology ,market economics ，andenvironmentalindustrial water efficiency value; WSS， WSG， WSR,awareness .Wsw, WSD, and WST mean the water supply resulting fromPopulation growth: Medium-term growth projetionssurface water, ground water, rain water utilities，waste waterindicated that China' s population will reach 1.35 thousandtreatment and reuse, salt water desalting, sea water desaltingmillion in 2010 and 1 .42 thousand million in 2025. Theand transfer water. SG, GD and GS are the indexes of foodannual population growth rate will continue to decline oversecurity，the total demand of grain, and the total supply ofthe next 25 years, the modeling time period of this study .grain in the target year respectively .The majority of the population increase will affect rural areas .Urbanization: In 2001， some 0. 46 thousand million2.2 Scenarios developmentFour scenarios were developed to simulate the futurepeople lived in cities(NBSC, 2000)，and it is expected thatby 2025, about 0.76 thousand million people, half the totalwater securities according to the current tendency andpopulation of China, will live in urban areas. Much of thisaccording to a sustainable pattem in this paper ( Gallopin,urban growth will be the result of intemal migration as more1999; 2000; Alcamo, 2000).rural citizens， especially the younger generations, abandonBAU ( the business-as usual scenario ) describestraditional rural life for that of the cities. And due to thesituation and trends in which current policies on waterrapid development of rural industries， the growth of smallresources management and development and lifestyle continuetowns in rural areas will further accelerate.in essence unchanged. Under this scenario, no majorTechnology: Rapid development and application ofchanges take place in the alterative trends of 16 decision-technology in the fields of information science ,making variables including population growth rate， thebiotechnology, water saving， water purification， and newincreasing ratio of urbanization， the decreasing ratio oftechnologies related to water use and water exploitation wicultivated land area， the decreasing ratio of grain-plantedbecome major driving forces in attempts to balance China ' sarea, the decreasing ratio of grain replanting, the increasingwater demand and supply.ratio of per. canita urban dornestic water use，the increasingEconomic development: As the most populateddeveloping country， China is under very high economicratio中国煤化工ater use, the increasingpressure to speed up its economic development ( ESCAP,|YHCNM H G the increasing ratio of1997).land- imigated share, the increasing ratio of irmigated waterEnvironmental awareness: Increasing awareness ofquota, the decreasing ratio of the share of irnigated water innatural ecosystems’ importance to future development willagricultural water consumption, the increasing ratio of grOSSgenerale pressure to improve the quality of retum flows toindustrial production, the increasing ratio of industrial water-No.5Scenario simulation of water security in China767Population growthEcoomic development. Life security.Pood securityEavironmental securityUrban populationDomucsecuntyEnvironmental qualityRural populationEcological BervicesDomestic watAgricultural waterBcorysterm waterWater demandWater savingWater stress..............................Water supply| Surface water Ground water Rain water utilities Waste water treatmoent Salt water desaltiog Sen water desalting Transfer waterWater resourcesexploitationFig.1 Conceplual moded of water security in Chinarecyeling proportion， the share of high- water-consumptionexpected that some effective and eco-friendly rules andindustries，grain demand per capita and water supply. Themeasures will be introduced such as reforming water resourcevalues of these variables are determined by establishingmanagement policies ，industrial structure adjustments， foodstatistical trend functions or correlative research results,and planting structure changes， and environmentally soundrespectively.values and behaviour. This can be represented by 6TEC( the technology and economics scenario) indicatedregulative decision- making variables including the increasinga water situation in which mainly relies on technologicalratio of per capita urban domestic water use, the increasinginnovation and transfer， on the condition that currentratio of per capita rural domestic water use, the increasingtendencies'economic development ，population growth, andratio of gross industrial production, the share of high-water-water resource management continue without impediment .consumption industries, grain demand per capita, and waterWater pricing， based on economic principles, will lead tosupply .rapid diffusion of technologies ，increased capital investmentTSD( the toward sustainable development scenario) isand reduced water demand( Rijsbermnan, 2000). In TEC, itregarded as an integration of TEC and IVL， which all ofis expected that the development of technology in the fields oftechnological innovation, institutional reform and behavioralinformation technology , communications ，and biotechnology ，enhancement could be simultaneous in the future. In thisas well as in new technology related to water use and waterscenario, all controlled parameters are changed according toexploitation in agriculture and industry， will speed up andthe scenario TEC and IVL discussed above .widely applied. This trend can be described by 5 regulative2.3 Simulation methodsdecision- making variables that include the increasing ratio ofIn the simulation, the base year is 2001 and the targetindustrial water- reeycling proportion, the decreasing ratio ofyears are 2010 and 2025. The main parameters and variablesimigated water quota, the increasing ratio of the grain yieldof base year are derived from statistical data. Someper hectare，the decreasing ratio of the share of irmigateduncertainties were identified in BAU, TEC，IVL, and TSDwater in agricultural water consumption, and the increasingscenario中国煤化工. to trends or eventsratio of land- rrigated share .thatanticipate such aIVL( the institution， values， and lifestyles scenario)improveYHc N M H Gation and uiztion,describes a situation in which a revival of human values,water-saving irrigation technology ，water- saving techniques instrengthened intermational cooperation, heavy emphasis onindustry, water resource management policies, relative laws ,education，intemational rules， increased solidarity， andindustrial structure adjustments， food and planting structurechanges in lifestyles and behavior take place. In IVL, it ischanges，environmentally sound values and behavior,768OUYANG Zhi-yun et al.Vol.16investment in R&D for water resource exploitation andbasic parameters and their values from the scenarios of BAU,utilization, grain importation, and so on. The parameters inTEC, IVL, and TSD are listed in Table 1. After validation,scenarios simulation can be calculated by relative kinds of the system model was programmed in STELLA 5.0( SEIB anddecision- making variables , and the values of these variablesTI, 1997). The water security of China was asessed in thecan be determined through establishing statistical trenddiferent scenarios .functions or citing the data of correlative research and reports3 Resultsrespectively. A few parameters are unchanged in the fourscenarios. because of the continuity and stability of someThe simulation results of BAU, TEC，IVL, and TSDnational laws and policies such as population growth,scenarios are as follows (Table 2) .urbanization，farmland， and industrial development. SomeTable 1 The basie parameters and their values used in scenarios20102025Parameters2001BATECIVLTSDBAUPopulation growth rate,哭0.650.0.3244.648.84837.7488127.6112.4107.414.07.0s.0428.6420.8451.0442.6Per capitu urbuan domestic water use, Ld218.0234.0230.0262.5255.3Per eapita nural domestic water use, Ld92.0102.2100.5126.5122.022.0Irigated area ratio, %50.051.052.063.064.0Imigpated waler quota, m' /hm2.7185.06930.0 6570.06930.06570.0 6630.06270.06630.0Industrial water reuse ratio, %56.657.765.871.171.The industrial waler eficiency value,78.060.661.031.126.8m/10* RMB YuanTable 2 The modeling results of BAU and TSDIndexCDP,1012 USD2.322. 14.824.45CDP per capita, USI1720158533983134Domestie water demand, 10°82.182 180. 80.6100.0.o0. .097. 097.0428. 4406.2436 2413 5441.5431.0Agrieultural water demand, 10" mIndustrial waler demand,221. ,9 .211.1221.9211. 1270. .g220.7.270. 87324817 2Water demand, 10° m'699.478.7812.3809.3646.0656.0720.0740.0Water deficieney percentage, %13.46.614.47.512.81.612.41.2Water security index86.693.492.587.6Total grain production, 10% t548.1554.1588.9617.9Grain yield, kg/hm24876.44929.75483.05753.c5753.4Grain per capita. kg406.0410.4435. 2435.2Grain demand, 10 t578.6565.1640.4628.5Grain balance, 10 t-30.5-24.5-17.0-14.0.51.5-22.5-39.6-10.6Grain deficiencgy ratio, %4.23.08.03.5.31.7Food secunity index94.795.897.596.598.3Under the BAU scenario, the Chinese economy willfall below the security line， which is represented by ancontinue to grow during the next 25 years.Althoughimport share of 8% of total grain provision .cultivated land in China will reduce mainly due to theScenario TEC and Scenario IVL have demonstrated therestoration of natural ecosystems, imigated areas in 2025 willinfluences of technical progresses， policy adjustments, andaccount for 62% of lotal cultivated land, and the grain yieldbehavior inducements on water supply and demand in China.will increase by 30%， The predicted increase in waterThe results showed that only technology solution anddemand will come mainly from industry and households, alinstutional reform can not ensure the water security inof which will double over the next 25 years . The water supplyChina.potential can be expected to improve slowly and the rapidUnder the TSD scenario, as a esult of investment ineconomic development will lead to increased water stress .hydrographical projects and technical improvement, the waterThis water shortage will be increasingly severe during thesupply potential can be expected to increase gradually. Waterperiod from 2001 to 2015 because the demand for water forexplsuch assaltandraineconomic development will exceed water supply. After 2015,water中国煤化工mil m in 2010 andthis stress will be slightly reduced thanks to significant59.0MYHCN M H G. Due to the extensivesocial，economic, and technical progress. The conclusionsdevelopment of new water-saving techniques in agriculturalpresented here are based on the average hydrological regime .and industrial sectors (Jin, 2001 )，especially water- savingIf some large- scale drought disasters were to occur in China,agricultural techniques, the total water demand in 2025 iswater shortages would be cnitical, and the grain yield wouldprojected to be 11 .6% less than in BAU, which industrial ,