Co-benefits of Local Air Pollutants and Greenhouse Gas Reduction Achieved by Hydropower Development in Xizang(Tibet) Autonomous Region, China

Hydropower development in Xizang(Tibet) Autonomous Region plays a vital role in co-control of local air pollutants and greenhouse gas(GHG) in China. According to emission factors of local air pollutants and GHG of coal-fired power industry in different hydropower service regions, we estimate the effect and synergy of local air pollutants and GHG reduction achieved by hydropower development in Tibet, examine the main factors constraining the effect and synergy, using correlation analysis and multiple regression analysis. The results show that: 1) During the period from 2006 to 2012, the effect of local air pollutants and GHG reduction achieved by hydropower development in Tibet decreased as a whole, while the synergy increased first and decreased afterwards. 2) The effect and synergy of local air pollutants and GHG reduction achieved by hydropower development in Tibet vary significantly across different hydropower service regions. The effect based on emission levels of Central China power grid(CCPG) and Northwest China power grid(NCPG) was more significant than that based on emission level of national power grid(NPG) from 2006 to 2012, and the synergy based on emission levels of CCPG and NCPG was also more significant than that based on emission level of NPG from 2010 to 2012. 3) The main factors constraining the effect and synergy based on emission levels of NCPG and CCPG included SO2 removal rate and NOx removal rate, the effect and synergy based on emission level of NPG was mainly influenced by net coal consumption rate. 4) Transferring hydropower from Tibet to NCPG and CCPG, and substituting local coal-fired power with hydropower can greatly help to co-control local air pollutants and GHG, transform the emission reduction pattern of the power industry and optimize energy structure.

Spatially-explicit quantitative relationship for a potential PES mechanism:Cascade hydropower development in Yarlung Zangbo River Basin, China

Payment for ecosystem services(PES) is of great importance for the sustainable development of mountain areas, key hotspot regions for the provisioning of ecosystem services. At present, PES researches mainly focus on forest protection, carbon sink trading, and water protection. As an important industry in mountainous areas, cascade hydropower development has generated substantial economic benefits accompanied by social and ecological impacts. However, efficient PES mechanisms to deal with hydropower generation in mountain areas are still unavailable. Therefore, the lacking of PES in mountain systems limits the development of those areas, and compromise the sustainability of hydropower development. The critical reason lies in the lack of a scientific method that can quantitatively analyze the relationship of hydropower stations with a geographical scope at county level(i.e., quantifying the water yield service provided by each county within the cascade hydropower development basin), and with different hydropower enterprises. We use the Yarlung Zangbo River Basin of China as case study area, one of the major hydropower development basins in China. First, we used Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST) model to map water yield service. Then, we calculated the value of water yield service by relating the water yield to the gross output value of hydropower stations. We revealed the relationship(e.g., hydropower stations and identified counties) between the payers and the payees of ecosystem services through mapping and quantifying the provisioning regions in the supply of water yield service and the users(hydropower enterprises). Finally, we discussed the current situation of benefit distribution in cascade hydropower development basin based on the supply and use of the water yield service. The results showed that 1) the spatial distribution of the value of water yield service is uneven: the upper reaches are highvalue areas;the eastern region is higher than the western region;and the maximum value(USD 119.2$/km2) is 34 times higher than the minimum value(USD 3.5 $/km2). 2) We found that four state-owned enterprises are the direct beneficiaries of water yield service, and 37 counties are suppliers, among which Gongbogyamda, Lhari and Damxung are the first level of supply. 3) Each hydropower station is provided with water yield service by several counties, and the value of water yield service varies greatly in each county, showing spatial differences. 4) Most counties are only partially involved in the process of water yield service being used by hydropower stations(i.e.,the boundary of water yield service is inconsistent with the administrative boundary). 5) Huaneng Tibet Yarlung Zangbo River Hydropower Development and Investment Co., Ltd. gets the greatest value(USD 1.8million $) from the use of water yield service, while China Energy Tibet Electric Power Co., Ltd. gets the smallest(USD 389.1 thousand $). 6) Counties near the lower reaches have gained more economic benefits, while the water yield service they provide have the lowest contribution to hydropower production. Our approach linked water yield ecosystem service and hydropower development effectively, and revealed their complex eco-economic relationship between producers and beneficiaries of ecosystem services, which provides key insights for the designing of a potential PES mechanism.

Environmental impacts assessment for hydropower development planning in China

This article briefly introduced China’s law framework and technical standards related to environmental impacts assessment(EIA) for hydropower development, and the EIA developing process for hydropower development planning. Authors summarized the working experiences about hydropower development planning EIA done in the recent years in China, discussed the considerations and methods of hydropower development planning EIA, and put forward the index system for hydropower development planning EIA initially.

Benefit-Sharing Mechanism of Hydropower Development:Nujiang Prefecture in Yunnan

Southwestern China contains rich hydropower resources and a high concentration of impoverished people. The acceleration of hydropower development is an important way for promoting the development of impoverished areas and improving the livelihood assets of rural households. Taking Nujiang Prefecture as our focal area we conducted enterprise interviews and government discussions to arrive at a benefit-sharing mechanism for hydropower development. We found that heavy tax burdens on enterprises, low compensation standards, unreasonable electricity prices and weak development conditions are the main reasons that hydropower development is not accompanied by local economic development and improvement in the livelihoods of rural people. Based on a specific factor model and the theory of persistent income, a theoretical model is proposed and used to assess the scenario before relocation and the scenario after relocation. On this basis, policy recommendations for benefit-sharing mechanisms of hydropower development are proposed.

Ecological Footprint of Hydropower Development in China and the Associated Reductions of Greenhouse Gas Emission

Hydropower, next to coal, is the second most important source of electric power supply in China. It amounted to 20.4% of the nation＇s total installed capacity of electricity generation in 2011. To provide a comprehensive picture of the development of hydropower in China and its potential environmental impacts, this study calculates the ecological footprint and greenhouse gas emission reduction of hydropower development in China over the past 60 years. The ecological footprints include the energy ecological footprint and arable land occupation footprint. The energy ecological footprint is calculated in terms of the area of the land which would be used for reforestation in order to assimilate CQ emissions from fossil energy consumption for hydropower development. The arable land occupation footprint is calculated in terms of the area of the land to be inundated by hydropower development. The calculated energy ecological footprint was 502 422 ha in 2010 or about 0.3% of total arable land in China and the calculated inundated land was about 1.42×10 6 ha or about 1.2% of total arable land in China. The regional power grid baseline method was used to calculate the greenhouse gas emission reduction. Results indicated that CQ emission reduction from hydropower development was increasing rapidly since 1949 and reached 5.02×108 tons of COe emission in 2010, with an accumulative total of 6.221×109 tons of CQ emission during the period 1949-2010.

Key technologies for the construction of the Xiluodu high arch dam on the Jinsha River in the development of hydropower in western China

Hydropower development in China is concentrated in the country's western regions.Among all the rivers in China,the lower course of the Jinsha River contains the richest hydro-energy resource,and therefore,4 mammoth hydropower plants are under construction on this particular section of the river at Wudongde,Baihetan,Xiluodu,and Xiangjiaba.The water-blocking structures of the hydropower facilities at Wudongde,Baihetan and Xiluodu are all arch dams of around 300 m high.In view of changes in the geological conditions at the foundation of the Xiluodu dam on the riverbed after excavation started,the designs of expanding foundation surface excavation and dovetailing the dam body and foundation rock on both upstream and downstream sides were introduced,allowing the arch dam and foundation to fit each other and improving the stress conditions of the dam body and foundation.By dividing the dam body into various concrete sections,the dynamic properties of concrete were adequately adjusted to the distribution of stress in the dam body.In addition,the use of the most optimal concrete material and mixture ratio allowed thermodynamics of concrete to satisfy the requirements of the strength,durability,temperature control and crack prevention of the concrete.Moreover,rigorous temperature control measures were introduced to prevent harmful cracking,thus enhancing the integrity of the arch dam.Furthermore,sophisticated construction machinery,scientific testing methods,and sound construction techniques were employed to ensure the uniformity and reliability of concrete placement.The "Digital Dam" for the Xiluodu project,which is based on the theory of total life cycle,has supplied strong support for construction process control and decision-making.

A new assessment method for comprehensive impact of hydropower development on runoff and sediment changes

The environmental impact assessment （EIA） of cascade dams building in international rivers has been widely discussed in China and ASEAN countries since the 1990s. In Southwest China, all the great mountainous rivers have been the major state base for large-scale hydropower development. Among these rivers, the environmental change and response of the watercourse under the cascade dams building in the upper Mekong （called Lancang River in China） has been the focus in recent 20 years. In this paper, the Lancang River, which has over 25 years of large-scale hydropower development, was chosen as a case study for establishing the affected evaluation indicators system and its regression model of runoff and sediment, determining the indicators weight by the hierarchy analysis method and factor analysis method, and setting up the quantitative evaluation models of indicators affected level based on the ＂marginal efficiency＂ principle. Using these methods and model established, the influence degree of runoff and sediment in the Lancang River from 1986 to 2007 were assessed. The major results are： （1） the impact of sediment transport change by the cascade development is much higher than that of the runoff change; （2） the years＇ number with different impact levels respectively are 72.7% as the ＂smallest＂ level, 18.2% as ＂smaller＂, and 9.1% as ＂general＂; （3） the change process of runoff and sediment shows a ＂U-shaped＂ pattern, which indicates the balance of sediment change because of the interaction of sediment reduction by Manwan reservoir storage and the increase by the Dachaoshan dam construction.

Multi-dimensional assessment of socioeconomic impacts of hydropower development—A case in the Upper Chuan River

The positive role of hydropower in climate change adaption is well accepted by the international community and has been highlighted many times,while the understanding of its impacts on socioeconomic development remains at the stage of rough estimation and qualitative description.The application of a multi-regional CGE model in this paper provides an effective tool for quantitatively assessing the socioeconomic impacts of hydropower development,reflecting its positive functions.This case study on the Upper Chuan River details the steps of model development,including impact mechanism analysis,regional delimitation,macro closure setting,shock selection,and database preparation.The results show the enormous economic benefits of hydropower development using various indicators such as consumption,investment,GDP,employment,and income.The study indicates that hydropower development is a win-win energy development mode which can help to realize the integration of sustainable development and climate change mitigation.Finally,potential improvements to the model are discussed.

Development of Hydropower Resources in Southwest China

There is a boom of hydropower development in Southwest China recently because of the abundant hydropower resources there, especially in Yunnan and Sichuan provinces, which has attracted the attentions of various major power generation companies and private enterprises. Based on the situation of hydropower development in the Southwest and combined with the analysis of prospective receiving market and the capability of electrical and mechanical equipment’s manufacturing, this paper discusses the main problems of the hydropower development in the Southwest and makes some suggestions for its orderly development and eff icient utilization.

The Small Hydropower in China-A Focus of World Attention

This paper describes the present situation, construction experiences, existing problems and the principal tasks in the development of small hydropower in China.

China Powers Up Hydropower Construction in Western Region

This paper introduces the abundant hydropower resources in western region in China, the role hydropower will play in the extensive development of western region, the finished reconstruction activities, as well as the basic thought and near and long term targets on western hydropower development.

Concerning about the threat of the excessive hydropower exploitation on the Western Sichuan eco-environment

The concept that the economic development and supremacy hydropower energy are superior to any others leads to the excessive hydropower exploitation of the west Sichuan, deeply threatening the fragile eco-environment in this area and that of the whole Yangtze River and even of the whole country simultaneously. The present paper put forward that hydropower should be developed with ecological, social, and economical concern. The primary, extensive, circling-developing development model should be altered immediately, and that based on caring about eco-environment, being harmonious to the regional eco-environment should be highlighted, and sustainability of hydropower should be paid attention to.

Two new species of Japalura(Squamata:Agamidae)from the Hengduan Mountain Range,China

Until recently, the agamid species, Japalura flaviceps was recognized to have the widest geographic dis- tribution among members of the genus occurring in China, from eastern Tibet to Shaanxi Province. However, recent studies restricted the distribution of J. flaviceps to the Dadu River valley only in north- western Sichuan Province, suggesting that records of J. flaviceps outside the Dadu River valley likely represent undescribed diversity. During two herpeto- faunal surveys in 2013 and 2015, eight and 12 specimens of lizards of the genus Japalura were collected from the upper Nujiang （=Salween） Valley in eastern Tibet, China, and upper Lancang （=Mekong） Valley in northwestern Yunnan, China, respectively. These specimens display a unique suite of diagnostic morphological characters. Our robust comparisons of phenotype reveal that these populations can be distinguished readily from J. flaviceps and all other recognized congeners. Herein, we describe the two Japalura lineages as new spe- cies, Japalura laeviventris sp. nov. and Japalura iadina sp. nov.. In addition, we provide updated con- servation assessments for the new species as well as imperiled congeners according to the IUCN crite- ria for classification, discuss the importance of color patterns in the diagnosis and description of species in the genus Japalura, and discuss directions for future taxonomic studies of the group.

Controls on geomorphic characteristics of the Xiaohei River basin in the upper Lancang-Mekong, China

Understanding the evolution of the fluvial geomorphology in an orogenic belt provides valuable insight into the relationship between upper crustal deformation and surface processes.The upper Lancang-Mekong River is in an area experiencing both uplift and erosion.The related processes provide a steady sediment supply to the lower reaches of the river and play an important role in the regional environmental changes.The Xiaohei(Weiyuan)River Basin is an important sub-basin in this area,which is characterized by large-scale topographic fluctuations,active tectonics and erosion,and anthropogenic activities.These different factors introduce numerous complexities to the local surface processes.In this study,we investigate and quantify the controls of geomorphic evolution of the Xiaohei River Basin.We located and mapped the main knick-zones within the channels and examined the main genetic factors,such as faults and stratigraphic differences.The results show that the areas with the lowest uplift rates are characterized by a low steepness index and are located in the southeastern part of the basin.The stream power of the mainstream increases downstream,with an average value of^122 W/m.The erosional activity of the various stream channels is intense.Overall,the basin tends to expansion,with only local instances of inward contraction.Our analysis confirms that a number of the geomorphic evolutionary characteristics of the Xiaohei River Basin are transient.In addition,the future potential for the increasing the number of dams and the hydropower development in the basin may weaken the expansion trend of the basin over a long period of time.

Past and Future Changes in Climate and Water Resources in the Lancang–Mekong River Basin: Current Understanding and Future Research Directions

The Lancang–Mekong River(LMR)is an important transboundary river that originates from the Qinghai–Tibet Plateau,China and flows through six nations before draining into the South China Sea.Knowledge about the past and future changes in climate and water for this basin is critical in order to support regio-nal sustainable development.This paper presents a comprehensive review of the scientific progress that has been made in understanding the changing climate and water systems,and discusses outstanding challenges and future research opportunities.The existing literature suggests that:①The warming rate in the Lancang–Mekong River Basin(LMRB)is higher than the mean global warming rate,and it is higher in its upper portion,the Lancang River Basin(LRB),than in its lower portion,the Mekong River Basin(MRB);②historical precipitation has increased over the LMRB,particularly from 1981 to 2010,as the wet season became wetter in the entire basin,while the dry season became wetter in the LRB but drier in the MRB;③in the past,streamflow increased in the LRB but slightly decreased in the MRB,and increases in streamflow are projected for the future in the LMRB;and④historical streamflow increased in the dry season but decreased in the wet season from 1960 to 2010,while a slight increase is projected during the wet season.Four research directions are identified as follows:①investigation of the impacts of dams on river flow and local communities;②implementation of a novel water–energy–food–ecology(WEFE)nexus;③integration of groundwater and human health management with water resource assessment and management;and④strengthening of transboundary collaboration in order to address sustainable development goals(SDGs).

The scheme optimization on construction diversion with discharge control feature of upstream operational reservoir

There is a discharge control feature of construction diversion system with the upstream operational reservoir. The risk evaluation model of construction diversion is established by taking into consideration the risk factors of construction diversion system with discharge control feature as well as their composition. And the risk factors include the upstream operational reservoir discharge control, the interval flood and branch flood and the diversion system itself. And then based on analyzing of the conversion relation between risk index and investment index of diversion scheme, the risk control and conversion principals of diversion system are put forward, and the feasible diversion scheme model is built. At last, the risk and economic evaluation and scheme economic feasibility analysis method of diversion scheme are shown by an example of construction diversion scheme optimization with the discharge control condition of upstream hydropower station. The study is valuable for establishment and optimization of construction diversion scheme with upstream reservoir discharge control.

Inter-annual variations in vegetation and their response to climatic factors in the upper catchments of the Yellow River from 2000 to 2010

To understand the variations in vegetation and their correlation with climate factors in the upper catchments of the Yellow River, China, Normalized Difference Vegetation Index（NDVI） time series data from 2000 to 2010 were collected based on the MOD13Q1 product. The coefficient of variation, Theil–Sen median trend analysis and the Mann–Kendall test were combined to investigate the volatility characteristic and trend characteristic of the vegetation. Climate data sets were then used to analyze the correlation between variations in vegetation and climate change. In terms of the temporal variations, the vegetation in this study area improved slightly from 2000 to 2010, although the volatility characteristic was larger in 2000–2005 than in 2006–2010. In terms of the spatial variation, vegetation which is relatively stable and has a significantly increasing trend accounts for the largest part of the study area. Its spatial distribution is highly correlated with altitude, which ranges from about 2000 to 3000 m in this area. Highly fluctuating vegetation and vegetation which showed a significantly decreasing trend were mostly distributed around the reservoirs and in the reaches of the river with hydropower developments. Vegetation with a relatively stable and significantly decreasing trend and vegetation with a highly fluctuating and significantly increasing trend are widely dispersed. With respect to the response of vegetation to climate change, about 20–30% of the vegetation has a significant correlation with climatic factors and the correlations in most areas are positive： regions with precipitation as the key influencing factor account for more than 10% of the area; regions with temperature as the key influencing factor account for less than 10% of the area; and regions with precipitation and temperature as the key influencing factors together account for about 5% of the total area. More than 70% of the vegetation has an insignificant correlation with climatic factors.