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.

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.

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).