1.2　Review of Research Status at Home and Abroad

Hydropower resources are part of water resources.Small hydro development is especially recognized by people at all levels.Research on developing and exploiting hydropower resources has been increasing since 1950s.The review of research results at home and abroad is as follows.

1.2.1　Optimal Allocation of Hydropower Resources

Many researchers started their study on optimal allocation of water resources with water resources issues.The research abroad on hydropower resources allocation began in 1950's.Later with the development of computer science,systematic analyses on water resources based on simulation technique,linear programming,non-linear programming,and dynamic planning developed rapidly and got widely applied;model based analysis was adopted to study the optimal allocation of water resources.In 1971,D.K.Marks proposed a linear decision-making model to describe the systematic water resources problems.In 1972,based on theoretic research and application of the systematic analysis in developing and utilizing water resources between 1950s and 1960s,Buras conducted a systematic study on theory and practice of allocating water resources,by focusing on how to apply mathematical programming and computational methods to systematic design and operational scheduling of water resources and corresponding analytic procedures.In 1974,L.Becke and W.W.Gyeh studied multi-functions of water resources.In 1975,Y.Y.Haimes applied multi-level management technique to a study on joint scheduling of water resources of reservoirs and aquifers.Reasonable allocation of water resources has been gradually progressed since 1990s.However,due to the worsening water pollution and water crisis,the water resources optimization targeting at maximal water yield and economic benefits was unable to meet the demands.The research on optimal water resources allocation was therefore transferred to water quality constraints,ecological and environmental benefits and sustainable development of water resources.

In order to the domestic research on optimal water resources allocation,He Beifang(1989)proposed a big system sequence alignment model where decomposition and coordination of large-scale system was utilized to tackle optimal allocation of regional water resources.Qiu Dong(2007)established a two-level decomposition and coordination model to use goal programming to industrial reconstructuring,and made a great achievement by applying the optimal model to systematic analysis and optimal decision-making on water resources in Zhengzhou.Cai Ximing et al.(1995)set up a multi-objective analysis system model and decision-making supporting system for water resources optimization,which included water resources into macro economic system and targeted not only economically,but also socially and ecologically.The decomposition and coordination model and hierarchical simulation approach to optimization proposed by Liu Bin et al.(2000)took the water resources in Yiwu City as the research project.Xiang Li(1999)established a multi-watersource joint optimal scheduling model based on system theory and practice,with maximal economic benefits or maximal water supply of irrigation areas as objective function and planting area or quota for water consumers as decision variable.After discussing the water supply model for complex water sources in northern cities suffering water shortage,including reservoirs,underground water,reuse water,transferred water,etc..Lei Yuqiong et al.(2009)conducted the optimal water resources allocation modelling which took a comprehensive consideration from social,economic and ecological perspectives.Liu Han et al.(2006)put forward a decision-making system with spatiotemporal operation model at its core and featured by process transparency and hierarchical interactive transparency,consisting of three interrelated modules,respectively,regional social and economic objectives,water supply,and spatiotemporal optimization of total water resources.The system could be used to scheme for coordinating regional social-economic development and water resources.Dong Zheren et al.(2009)did some structural research on urban water resources utilization in Qinhuangdao City by applying integrated model of multi objective programming and inputting results to a system dynamic model,which reasonably predicted social,economic and environmental consequences after implementation of planning.Considering harmonizing water resources development with macro sustainable development goals,Huang Jianzhong(2003)established a multi-objective group-decision-making model for water resources planning in Dalian City from a macro economic perspective.He also proposed a multi-target Chebyshev fuzzy group decision-making approach in accordance with the multi-level,multi-target and multi-decision-maker features of decision-making model and in combination with engineering fuzzy set theory and Chebyshev decision-making method.

The focus of research on optimal hydropower resources allocation is about the stakeholders.In its report to a UN(United Nations)supported environment project on benefitsharing issue,EGRE elaborated on two aspects.One was attributes of benefit sharing,including the necessity of benefit sharing in constructing reservoirs,the objective and types of benefit-sharing mechanism.The other was the relevant approaches and practices,including the existing economic rent and fiscal restraints,coordinating stakeholders'interests,ensuring efficiency of interest redistribution,integrating local community,and defining duty scope of administration.Some analysis on these was also made with examples.He also discussed the stakeholders of dam construction projects,such as project developers,beneficiaries,victims,and government,and pointed out the benefit-sharing mechanism could be in monetary or non-monetary forms.The non-monetary benefit sharing referred to the compensation policies like land irrigation,chances of obtaining a job in the project,etc.The monetary benefit-sharing meant that the huge amount of economic rents brought by exploiting hydropower resources be shared with those whose interest was damaged due to the exploitations.Additionally,he classified the monetary benefit-sharing mechanism into several categories,namely,revenue sharing,growth fund,equity sharing,tax preference,and preferential feed-in tariffs.

In its recent research report,China Renewable Energy Engineering Institute pointed out that the benefit distribution in developing hydropower resources was not well justified.It suggested that tax(value added tax and business income tax)distribution policy be more skewed towards the resources areas,and the relation between tax payment and registry area be taken into better consideration.It said the value of hydropower resources was not fully displayed,and problems,such as the insufficient compensation on utilizing natural resources and negative external impacts of exploiting resources,were mainly tackled by the government.As stated in the report,overall considerations should have been given to the benefit distribution for up and down stream areas while developing hydropower resources in cascade way,to avoid such problems as unpaid compensation on downstream cascade hydro plants from the upstream plants with better adjustment capacity,unshared construction and operation cost by beneficiaries of comprehensive development of hydropower resources,and not enough concern on results from investment.The report also indicated that the low feed-in tariff of hydroelectricity prevented the hydropower resources from promoting economic and social development,for instance,the benchmarking feed-in tariff of hydropower was 0.08-0.12 yuan/(kW·h)than that of thermal power.It is therefore suggested that nationwide benchmarking feed-in tariff of hydropower electricity and time-of-use price be set in some provinces.Income-sharing mechanism,as the report stated,referred to a system where part of the hydropower project income would be reallocated to local water administration or local government in forms of royalties or resource rents(paid use of resources).The royalties fall into three types based on the ways the fees are charged,by output,product values or profits.The three types of resource rents can be used in a mixture.

Featuring stakeholders of hydropower development companies by specific investment,business risks undertaking,active or passive interrelationship,particularity of public resource enterprises,and so on,Ke Wugang(2002)listed the stakeholders of hydropower development,including local government,environment agency,investors,loaners,employees,management,local residents,resettlers,etc.Jiang Hong et al.(2007)identified stakeholders of large-or medium-sized hydropower development projects as water administration,local governments of resettlement and migrant regions,investors,loaners,construction enterprises,managerial staff,employees,resettlers,environment agency,grid enterprises,design institutes,consultancy enterprises,suppliers,non-governmental organizations,news media,industry associations,the public,etc.Shi Guoqing et al.(2008)defined stakeholders of a hydropower development company as groups or individuals who actively invested or passively lost some financial,human and physical capital,and other valuables that might have brought economic profits,and who were willing to bear any risks.Based on these research achievements,stakeholders can be clearly defined based on property right and contract,taking participation and possession as the essence.

Liu Aiqing(2011)pointed out that the stakeholders of large and medium hydropower projects are group or individuals who contributed specific investment to the projects which might bring benefits.The specific investment might include physical,human,financial,ecological,and social capital aspects,and project benefits might include economic,social and environmental values.The groups or individuals are directly or indirectly contractually connected with the projects,and actively or passively taking the risks and benefits in the process of investing and rewarding.Their activities affect and are affected by the realization of project objectives.

1.2.2　Paid Use of Hydropower Resources

The study on paid use of hydropower resources is mainly from the perspective of resource ownership and its value.Li Chunyan(1991)found that local people living in an area rich in natural resources could benefit sufficiently from exploiting the resources in some foreign countries,whereas it was not the case in western China.Therefore,measures were suggested to protect the benefits of local people.For instance,share proportion of resources compensation for local people in provinces rich in mining resources should be raised;gas and oil resources taxation and compensation for minery resources should also be raised;allocation proportion of resources compensation at state and regional levels should be adjusted to improve paid use mechanism of natural resources.Xi Bu(2008)suggested that part of profits of hydropower development should be set aside as compensation on using the resources for resettlement and ecological protection.A market-based hydro benefit formation and allocation system should be established with attentions paid to social benefits and reasonable government intervention,after clarifying hydro product pricing policies,paid use mechanism of hydropower resources,and social benefit evaluation and compensation mechanism.The paid use system of mineral resources consists of resource tax,compensation fee,resource use fee(for prospecting and mining rights),and resource price(for prospecting and mining rights),covering the whole process of obtaining,owning,using and transferring natural resources,and featured by both taxes and fees.In combination with the paid use system of mineral resources,Lao Chenyu(2013)pointed out that hydroelectricity is the product of hydropower resources which are owned by the state as the mineral resources.The owner of the hydropower resources as an important economic resource in accordance with either Marx's Land Rent Theory or return law of economic factors,is entitled to income right,that is,resource rents.Therefore,it is absolutely possible to establish paid use mechanism of hydropower resources based on the management system of exploiting mineral resources.

Some study from the perspective of the full-scale development program for the western regions and the West-East power transmission project,found that the current approach towards hydropower resources development was typically a plundering of resources.Because the resources assets management ideas,such as the asset attributes of water resources,cost of utilizing resources,paid use of resources,etc.were not well recognized,developers could obtain the right to use hydropower resources at no cost and dominated the exploitation,and it was difficult to coordinate the interests of all parties concerned.According to the national resettlement policies and regulations,for large and medium hydropower projects with reservoir inundation,plans of relocation,resettlement and rehabilitation must be compiled based on the“Three Originals”principles(namely original scale,original standard,and original functions).The relocation,resettlement and rehabilitation plans for reservoir inundation were carried out in accordance with the mandatory and standardized norms that the state government set for public infrastructure,and respects were also paid to the combination of local development and project construction and operation.However,local development usually was long-term oriented,and the government of inundated state poverty county was short of sufficient supporting funds.In addition,the shortfall in funding for constructions with raised standard and enlarged scale forced the local government to ask the project owners to fill the gap essentially through exploiting the resources.The owners,faced with the interest appeals of resettlers and local economic development,asked for a kind of mechanism to share responsibity,benefits and risks while developing and managing hydropower resources for the purposes of settling issues with policies and institutional arrangement.

Dong Wenhu(2001)considered that the long run production and development of resettlers,increase of farmers'income,incentives for local economic and social development,and support for local industries,all required a sound settlement of profit distribution and long-term mechanism for exploiting and harnessing hydropower resources in western China.The hydropower resources at the lower reach of Jinsha River were mainly transmitted to the middle east and coastal areas.Therefore,it was necessary to establish a longterm mechanism to take into consideration the benefits of the local inundated areas for paid use of resources.The mechanism might include the followings.First,while guaranteeing the competitive floor price in electricity consuming areas,due consideration should be given in electricity pricing to local economic and social development,as well as production and living support for resettlers.Second,more fiscal revenue that the central and local government gained from the construction and operation of hydro plants should be allocated to the local government and resettlers of the inundated hydropower resources areas.Third,due consideration should be given to the government investment at provincial,municipal/prefecture and county levels while the local government benefited from being shareholder of hydro development.Fourth,long-acting resettlement should be explored to ensure that the compensation and subsidies for land occupation were used both for production and living,and investment and further development as well,which required an analysis on land compensation fees and the basic living standard of rural resettlers.Fifth,electricity consumption incentives should be explored for resettlers and local government of inundated areas to make preferential power supply and price a basic drive for local production,living and economic development.

Gao Dengkui et al.(2010)considered that onefold policy of paid use of hydropower resources might not be very efficient as it would retain some clearly defined resources,such as water resources at embankment sites,water area resources,and water energy resources,as state owned.In addition,state ownership of hydropower resources is realized by charging the use of resources,which would certainly raise the cost of using water resources and have adverse effect on encouraging hardworking project owners as a big part of income did not go to themselves.Therefore,the one-fold water resources compensation fee does not comply with the efficiency policy in economics where the property always chases after profits.If only onefold compensation for the right of development is adopted,some not so clearly defined hydropower resources would be forced to be privately owned.Consequently,too high compensation cost would increase risks and attract no investment on developing hydropower resources;while too low compensation cost would impair the property right of the State and cause social inequity and instability.So,the onefold water resources compensation policy is not in accordance with property right hierarchy theory.In short,state equity income of hydropower resources should be earned through both compensation fee for the right of development and the paid use of water resources.

1.2.3　Resources Compensation in Hydropower Development

To establish hydropower resources property right system with clear ownership relations,the first important thing is to identify stakeholders of hydropower projects based on sound understanding of the concept of“stakeholder”.International experience shows that in a hydro project wider range of stakeholders always favors greater fairness and social recognition.The establishment of stakeholders'role as players of hydropower resources market enormously increases the participation of affected people and greatly contribute to the balance of interest.In China,hydro projects are featured not only by its profit-driven nature,but also the nature of quasi-public goods such as navigation,irrigation and water supply,and nature of pure public good like flood control.Quasi-public goods,like irrigation and water supply,could be transformed to private goods by charging the beneficiaries.The World Dam Committee studied the stakeholders of dams and identified such major stakeholders as local government,social groups,affected people,professional associations,multilateral supporting organizations,and multilateral development banks.It required that stakeholders coordinate with each other,assess together right from the selection and planning phases and throughout the whole process of a certain project to eliminate those unqualified project to ensure the benefits of those who are affected adversely.

Wang Wanshan(2003)explored ways of optimizing resources property market system from the prospective of three levels of natural resources equity transaction,i.e.initial property right definition,provisions on trading right,transaction system.He also put forward a successive and progressive three-step approach to system transformation.Firstly,establish market-oriented public property regulation mode;secondly,marketize the right to use and manage natural resources under the current ownership;thirdly,implement pluralistic and marketized ownership system where there is a mixed market of resources property right with both private and public ownership.It is also suggested that a diversified ownership system should be established in accordance with property right diversification of natural resources,an authoritative natural resources management agency be established and strengthened to regulate natural resources property market with property system.

Up to now,there is no established hydropower resources trading platform.Water right trading,in general,covers the transactions of water resources ownership(including hydropower resources ownership)and many water-use-related rights,including right of developing,using and managing water resources and other water related rights.With the improving pertinent regulations,the rights of using and trading water resources will be allocated nationwide.If the water facilities were built for exchanging water rights as an indirect trading method,there could be a triple win in terms of industrial,agricultural and environmental development.However,it is worthwhile to note that the direct water rights trading solely for profit seeking could adversely affect regional industrial restructuring,and the government should get involved to provide guidance in the case.In the Eleventh Five-year Plan,it was stated that water licensing and paid use of water resources should be improved;total quantity control and quota management should be incorporated in one system;basin management and regional management should be combined in water resources management system;and initial water right allocation system and water rights transfer system should be established at national level.

Water rights trading is very similar to carbon trading.Both have the same consideration on environmental protection and reasonable utilization of natural resources,and take energy saving projects as intermediary.Carbon trading is based on emission-reducing projects,while water rights trading is based on projects rationally using water resources.However,the water rights trading is still at its preliminary development stage with private investment only on small-scale surface water storage projects such as small reservoirs or dams.Little financial capital is attracted to water rights trading market.

In terms of physical trading platform,traditional Stock Exchanges,like NYSE Euronext,have already listed carbon trading,so carbon is traded on a global trading platform.Nevertheless,there is not such a large exchange platform for water rights trading.According to the Measures for the Management and Implementation of Transferring Yellow River Water Right,Yellow River water right could only be traded within the province.Practically,water right trading markets were established more at prefecture-level cities in Yellow River basin.For instance,in Dunhuang,water right market was set to tender,auction or buy-back water rights.In Wuwei,Gansu,a coupon-based trading system was established by allocating water rights to more than 310,000 farmer households in forms of water coupons.In Zhejiang,paid transfer system for exploiting hydropower resources has been carried out for almost ten years.Many ways were adopted to auction hydropower resources in different counties or cities with considerations given to real situations and operations.Varied successes were made mainly through Zhejiang public resources bidding market.

Shen Manhong(2004)said that Zhejiang took a leading role in transferring the right of developing hydropower resources by auctioning.The paid transfer of hydropower resources development right was realized in many different ways through practicing hydropower resources auction.There are two reasons contributing to Zhejiang's leading role in transforming resources allocation and introducing auction.One is the mature market environment,and the second is that the local government regards small hydro development as an approach to enriching the remote hilly areas,and infroduces series of preferential policies to attract private investments on small hydro,which provides material prerequisite for paid transferring of hydropower resources.

1.2.4　Economic Compensation in Hydropower Development

The international practices showed that the exploitation of cross-border rivers was carried out according to established rules based on co-developed planning and correspondingly stipulated agreements.Those agreements or rules were signed abiding by the principle that those who benefit should undertake responsibilities and compensate those who provide benefits.Once the compensation principle was set,it would remain relatively stable and be implemented taking long-run benefits as basis.

For instance,the River Danube,Europe's second longest river,flows through Germany,Austria,Hungary,Yugoslovia,Rromania,etc.In order to jointly develop the hydropower resources of the river,convention between the government of the Socialist Federal Republic of Yugoslavia and the government of the Romanian People's Republic concerning the preparation of designs for the construction of the Iron Gates water power and navigation system on the River Danube was signed on November 30,1963.It set the total amount of funds for construction,investment ratio and methods,main engineering indicators,commissioning and operation timing,operational mode,maintenance requirements and cost,and so on.It guaranteed the successful construction and operation of Iron Gates projects and the efficient use of water resources.

As for domestic research,Liu Bin et al.(2007)collected series of economic materials in 1990s and adopted the grey system theory and made a conclusion to analyze and assess the influence of water resources construction investment on national economy.It was concluded that investment on water resources construction influenced GDP the most,farmer per capita net income the next,and grain yield the least.The influence on GDP was greatly reflected in the second industry,and least in the first industry.

While exploiting water resources for power generation,the economic benefits of other water consumers are affected.If they are not compensated for the loss of their benefits,the one who obtained the permit of project development does not actually own the right of using the hydropower resources.Only when the other water consumers are compensated for their lost benefits and acknowledge the developer's right of using water resources can the value of hydropower resources be realized.

Hydropower resources compensation could be divided into two types,monetary and non-monetary.Currently,the research is mainly made on monetary compensation.The poolicies and measures that the government adopted to regulate optimal allocation of hydropower resources include revenue-sharing royalty expense,auction and transfer of the right of exploiting resources,disposition of resources income with taxation,etc.In most revenue sharing cases,no specific allocation proportion was made.How to determine the allocation proportion is key to benefit-sharing and necessary consideration should be given to the real situation.

From the perspective of resettlement,Feng Shangyou(2000)studied the benefit sharing mode in resettling people for construction of dam and proposed that whether the production and living standard of the resettlers could be improved or not with benefit-sharing in water conservation and hydropower projects should be regarded as a major criterion for dam construction.Therefore,it is important to set up a reasonable project benefit-sharing mechanism to balance the relation between the beneficiary and the benefiter.Dai Songchen(2012)put forward a benefit-sharing mode where resettlers shared the benefits and get self-employed,and they participate in the benefits allocation based on the value of the resources they put in the project.In other words,the land compensation and resettlement fees that the resettlers obtained should be transferred as capital invested on hydro projects.

From the perspective of resettlers as investors,Huang Jianzhong et al.(2003)explored developer/investor type of resettlers after comprehensively considering the resettlers,hydroelectric power station investment and benefits and other technical and economic features of hydro projects.Wang Shucheng(2001)analyzed the funding,shareholding and proportion,preferential policy mix,equity loan repayment,etc.and proposed that investortype of resettlers take share in hydro plant operation by investing their habitation and right of land use.In other words,the state owns the resources assets while the resettlers own the corresponding equity assets.Currently,some hydro plants use some of their operating profits to compensate the resettlers for their losses,which is also a type of assess management.But in a long run,it would be more reasonable for the resettlers to hold a share in the project.

1.2.5　Ecological Compensation in Hydropower Development

Early in 1908,the concept of river basin management was put forward in the United States,which considered the water environment of a river basin in its entirety and the accounting of environmental water consumption was an important part of water resources management.In 1940,United States Fish and Wildlife Protection Organization defined the environmental water demand as the demand of water resources for fish,wildlife,entertainment and aesthetic purposes.A lot of work has been done in America to calculate the minimum ecological flow of river and some algorithmic methods have been proposed.In 1960s,reforms on water resources management system were carried out in Britain,and Water Resources Bureau was established;in 1970s,the National Water Resources Council was established,responsible for centralized water management by coordinating in water resources allocation between different departments to realize an integrated management of surface water,underground water,water supply and drainage,water quality and quantity.Water Law issued in France in 1992 stipulated that the minimum ecological flow or river should be guaranteed;and in the fishery law and countryside act,it was required that the minimum flow of river should be guaranteed in the construction and operation of water conservancy projects.In 1996,Gleick provided a clear definition of the Basic Ecological Water Requirement,i.e.a certain amount of water of certain quality for natural ecological environment to minimize changes on natural ecological system to protect species diversity and ecological integration.

In 1940s,an American resources management agency started to focus on the fishery degradation caused by the construction of dams.Environmental Ef fects of Large Dams,a book published by the Environmental Effects Branch of the United States Committee on Large Dams in 1978,summarized the research findings of the environmental effects of large dam construction between 1940s and 1970s,covering the effects of dam constructions on fish,algae,aquatic life,wildlife,reservoir evapotranspiration,downstream river channels,reservoirs,and downstream water quality.Beneficial effects of reservoirs were also analyzed.But these findings were made from the perspectives of dam's effects on the physical and chemical properties of water body,individual organism,population size,river way evolvement,etc.on a small spatial and temporal scale,and no association study was yet made on the biological community,ecological system and the interrelationship between various effects.A logistic model was established by Morita et al.to study the influence of barrier effect brought by the dam construction on the survival conditions of salvelinus leucomaenis,and it was found that 87.5%of this white spotted char and one third of its habitat would vanish in 50 years due to dam barrier effect.

For domestic research,Duan Weijun et al.did a lot of work on the ecological environment impacts and effects that the cascade hydropower development of Langtang River basin in longitudinal range-gorge region had produced.Deng Yun et al.used a mathematical model to study the cumulative impact of cascade hydro plants on water temperature.The distribution of water temperature in reservoir areas and outflow temperature were analyzed when the Jinpin Hydro Plant CascadeⅠand Ertang Hydro Plant over downstream Yapan River were jointly operating,and they were compared with the thermal conditions when the Ertan Hydro Plant operated alone.It was found that the reservoir of Jinpin Hydro Plant CascadeⅠwas stably stratified:the water temperature at reservoir bottom kept low at 8.6℃;the surface water temperature before the dam was 12.7-24.2℃;and the outflow temperature was significantly delayed.

In 21st century,sustainable development is globally understood that ecological environment should be protected while developing society and economy.Social and economic development should not be made at the cost of ecological environment,and a sustainable development model should be established to seek a harmonious and symbiotic relations with ecological environment(Magurran,A.E.,2003).

Magurran(2003)pointed out that the external world and the nature function on the ecological system either positively or negatively.The influence that the resources exploitation makes on the complex ecosystems is no longer the simple mixing of effects on subsystems.The bearing capacity,adaptability and dynamic mechanism of ecosystem determine that its response to resources exploitation is not a linear dependency.It is a collaborative,thresholding,and complex non-linear relation.The dynamic synergy analysis on the changes of ecosystem featured by varied temporal and spatial distribution in a river basin found complicated synergistic or antagonistic actions between the known environmental factors,which made it difficult to measure or empower the cumulative contribution each factor could make to the complex ecosystem environment.The importance empowerment of environmental factor is subject to threshold limit value in a non-linear or non-scaling progressive way.

The ecological environmental effects of cascade hydro plants are originated from those of individual hydro plants.The environmental impact(EI)of a hydro plant could be divided into three parts according to the time when it takes place,i.e.the construction period,reservoir impounding period and power station operation period.During the construction of a hydro plant,the vegetation cover would be significantly degraded;the dust and noise produced are harmful to human health;the discarded soil and waste slag would worsen the regional water loss and soil erosion and even cause secondary geological disasters if they are not treated and dumped.After the impounding of reservoir,the downstream water flow would be greatly decreased,and the physical properties of water body are likely to be changed to consequently affect the ecological environment.Additionally,the expanded water area would significantly alter the landscape pattern of that area.The operation of hydro plant would have some impacts on the reservoir area and the connecting upper and lower river reaches(mainly the backwater area and tail water area).Specifically,the impacts are on the fish,aquatic plants and animal,resettlers'living conditions,reservoir nutrition status,and even the water quality of the connecting reaches.In recent years,some domestic scholars studied the ecological environmental impacts of individual hydroelectric projects at Sanmenxia,Ertan,Manwan,Xin'anjiang,Fuchunjiang,and Baozhusi.

Reservoirs can adjust the natural runoff through impounding or discharging water.Reservoir scheduling means regulating water resources by purposefully impounding or discharging water inflow according to the working conditions and hydrological forecast and abiding by the principles of ensuring project safety and downstream protection and comprehensive utilization of water resources,so that flood control and irrigation efficiency would be realized.Currently,there are many different classification of reservoir scheduling based on functions of regulation,regulating period,runoff description,and number of purposes taken into consideration.Namely,there are regulations for flood control,electric power generation,ecological protection or water supply,long-,medium-,short-termed or realtime regulation,deterministic or stochastic regulation,single-objective or multi-objective optimal regulation.The research on reservoir optimal scheduling divides it into regular scheduling and optimal scheduling.

1.2.6　Comments on Research Status

The optimal allocation mechanism for hydropower resources belongs to the category of resources allocation which is a core issue for economic study.More has been achieved in research on resources allocation theory and practice in developed countries than in China.But when we examine the current allocation of hydropower resources,it can be found that the theories and opinions on resources allocation in foreign countries,though useful in several aspects,are far from the reality of economic and social situation in China in the following ways.

Firstly,the studies abroad are mainly conducted in certain developed countries where there is no such prominent conflict between population and resources as in China.The total amount of any kind of resources in China is very likely to top out,however,with a population of over 1.3 billion,the per capita quantity of resources is in the bottom.

Secondly,a lot of research results were achieved in countries with mature market economic system.China is now in the transitional stage of building up socialist market economic system after undergoing socialist planned economy for a long time.The difference in terms of basic economic system makes entirely contrary prerequisite of economic analysis,which would inevitably influence the study on hydropower resources allocation.

Thirdly,the research findings were made in generally balanced economies.Whereas in China,Reform and Opening-up has been adopted to enable compressed modernization,which meant that the achievements of industrialization and urbanization to some extent were made at the cost of the rural,ecological benefits and farmers'interests as well.The economy was typically featured by imbalance.

As shown above,the hydropower resources allocation in China is completely different from other countries in terms of natural,economic and social conditions.The theoretical achievements that other countries made in resources allocation are not sufficiently applicable to the allocation of river basin water resources in China for the lack of forward-looking guidance to further optimal allocation.It was under such a background that the study is conducted on optimal hydropower resources allocation mechanism in the project captioned.