Achieving fish passage outcomes at irrigation infrastructure;a case study from the Lower Mekong Basin

Irrigation infrastructure expansion threatens the diversity of freshwater fish worldwide.Irrigation infrastructure creates migration barriers which can block access to important nursery,feeding and spawning habitat.Lao PDR is a landlocked country situated within the Lower Mekong River Basin where there is a substantial dependency on rice and fish for food,income and livelihoods.The country is experiencing an unprecedented boom in irrigation infrastructure investment,with modernisation programs being implemented in every province.Despite significant investment in infrastructure upgrades,and the potential impact on freshwater fish,little consideration has been given to fish passage solutions.In 2008,we commenced a fish passage program in Lao PDR.The intent of this case study is to outline the pivotal elements of the program of knowledge development and transfer,in the context of river connectivity and fisheries management in Lao PDR.We also highlight challenges in international research in development and lessons learned.

A Risk-Based Multi-Criteria Decision Analysis Approach to Evaluating Transboundary Water Development—The Case of Lower Mekong River Basin

The Lower Mekong River basin (LMB) covers the lower part of the Mekong river basin, including Laos, Thailand, Cambodia and Vietnam. Due to numerous pressures from high population growth and intensive hydropower development, the LMB has been facing significant challenges concerning its biodiversity and ecosystem. In 2017, Mekong River Commission (MRC), an intergovernmental organisation founded in 1995 among LMB countries, established the Council Study, which analysed the impacts of water development scenarios concerning the environmental, socioeconomic aspects of the LMB. This paper explores the nature of risks to the LMB water development and subsequently evaluates LMB’s water development scenarios described in the Council Study by using a multi-criteria decision analysis (MCDA) method. MCDA method has been widely applied in the field of water resource management in order to assist the decision-making process by systematically evaluating a certain number of alternatives against well-selected criteria through a preference rating scheme. By implementing a risk-based comprehensive assessment of the LMB transboundary water, this study provides insights into the impacts of the increasing risks to the ecosystem and human beings on the water development of the basin over time, which assists to change the awareness and the perspective toward humans’ risks and transboundary river ecosystem of decision-makers. This paper provides valuable recommendations for MRC to improve their policy concerning benefit-sharing scheme, water planning and risk mitigation strategies.

Hydrological Simulation Using TRMM and CHIRPS Precipitation Estimates in the Lower Lancang-Mekong River Basin

Satellite-based products with high spatial and temporal resolution provide useful precipitation information for data-sparse or ungauged large-scale watersheds. In the Lower Lancang-Mekong River Basin, rainfall stations are sparse and unevenly distributed, and the transboundary characteristic makes the collection of precipitation data more difficult, which has restricted hydrological processes simulation. In this study, daily precipitation data from four datasets(gauge observations, inverse distance weighted(IDW) data, Tropical Rainfall Measuring Mission(TRMM) estimates, and Climate Hazards Group InfraRed Precipitation with Stations(CHIRPS) estimates), were applied to drive the Soil and Water Assessment Tool(SWAT) model, and then their capability for hydrological simulation in the Lower Lancang-Mekong River Basin were examined. TRMM and CHIRPS data showed good performances on precipitation estimation in the Lower Lancang-Mekong River Basin, with the better performance for TRMM product. The Nash-Sutcliffe efficiency(NSE) values of gauge, IDW, TRMM, and CHIRPS simulations during the calibration period were 0.87, 0.86, 0.95, and 0.93 for monthly flow, respectively, and those for daily flow were 0.75, 0.77, 0.86, and 0.84, respectively. TRMM and CHIRPS data were superior to rain gauge and IDW data for driving the hydrological model, and TRMM data produced the best simulation performance. Satellite-based precipitation estimates could be suitable data sources when simulating hydrological processes for large data-poor or ungauged watersheds, especially in international river basins for which precipitation observations are difficult to collect. CHIRPS data provide long precipitation time series from 1981 to near present and thus could be used as an alternative precipitation input for hydrological simulation, especially for the period without TRMM data. For satellite-based precipitation products, the differences in the occurrence frequencies and amounts of precipitation with different intensities would affect simulation results of water balance components, which should be comprehensively considered in water resources estimation and planning.

Evaluation of Transboundary Water Resource Development in Mekong River Basin: The Application of Analytic Hierarchy Process in the Context of Water Cooperation

Mekong River is one of the major international freshwater sources in the world. The Lower Mekong Basin (LMB) comprised of four downstream countries, including Thailand, Lao PDR, Cambodia, and Vietnam. The utilization of the basin’s water brings not only substantial benefits to the region ranging from hydropower to navigation, but also negative impacts caused by the unbalanced water using. The essential role of Mekong River requires all member nations to cooperate effectively for the sustainable development of the region. One of the most popular methods in the field of water resource management is a trustable tool called the Analytical Hierarchy Process (AHP). AHP is much appropriate for water resource policymaking. The literature, however, points out that there is no study to both structure the water using hierarchy and employ quantitative (objective) criteria to the AHP model in LMB case. With regard to water resource management, there are no previous studies applying AHP models to evaluating sustainable development of transboundary water resource in LMB case. This paper explores the evolution of water cooperation among Mekong countries and subsequently evaluates the water development scenarios in the LMB based on the water cooperation preferences of four LMB countries This study proposes a novel approach to analyzing, assessing water resource development scenarios characterized by sustainability indicators and to assisting in developing a suitable water policy in LMB according to the best cooperation scenario.

Using Artificial Neural Network to Estimate Sediment Load in Ungauged Catchments of the Tonle Sap River Basin, Cambodia

Concern on alteration of sediment natural flow caused by developments of water resources system, has been addressed in many river basins around the world especially in developing and remote regions where sediment data are poorly gauged or ungauged. Since suspended sediment load (SSL) is predominant, the objectives of this research are to: 1) simulate monthly average SSL (SSLm) of four catchments using artificial neural network (ANN);2) assess the application of the calibrated ANN (Cal-ANN) models in three ungauged catchment representatives (UCR) before using them to predict SSLm of three actual ungauged catchments (AUC) in the Tonle Sap River Basin;and 3) estimate annual SSL (SSLA) of each AUC for the case of with and without dam-reservoirs. The model performance for total load (SSLT) prediction was also investigated because it is important for dam-reservoir management. For model simulation, ANN yielded very satisfactory results with determination coefficient (R2) ranging from 0.81 to 0.94 in calibration stage and 0.63 to 0.87 in validation stage. The Cal-ANN models also performed well in UCRs with R2 ranging from 0.59 to 0.64. From the result of this study, one can estimate SSLm and SSLT of ungauged catchments with an accuracy of 0.61 in term of R2 and 34.06% in term of absolute percentage bias, respectively. SSLA of the AUCs was found between 159,281 and 723,580 t/year. In combination with Brune’s method, the impact of dam-reservoirs could reduce SSLA between 47% and 68%. This result is key information for sustainable development of such infrastructures.

澜沧江下游/湄公河上游片断热带雨林物种多样性动态(英文)

在澜沧江下游/湄公河上游的滇南西双版纳地区,通过样方法比较了热带雨林的连片与 3个小片断的物种多样性变化趋势。与连续森林比较,片断热带雨林的植物物种丰富度和物种多样性指数都比较低,而且有相当低比例的大高位芽、中高位芽和附生等生活型植物,而藤本、小高位芽和矮高位芽等生活型植物的比例则较高;泛热带、热带亚洲至热带非洲的区系成分比例较高,而当地成分则减少;群落的上层树木比下层树木更加稳定。同样,动物的物种多样性指数和均衡度在片断热带雨林中都较低,与其密切相关的是片断热带雨林的环境质量,而不是片断的大小。此外,也探讨了片断热带雨林物种变化与森林小气候的关系,阐明了由凉湿向干暖转化的 林内效应"是其物种变化的重要原因之一。

湄公河计划的区域合作实践与“湄公精神

1957年10月,下湄公流域协作调查委员会(湄委会)成立,湄公河计划正式启动,直至1975年转型。其间,湄公河计划的区域合作实践取得了丰硕成果。一方面,在湄公河流域启动和建成一大批水电站、排灌站、水文站、气象站和试验农场等重要设施,并在航道改进及经济、社会诸领域取得重要进展,为湄公河流域的持续开发和治理奠定了稳固的物质基础。另一方面,在行动和规范上逐步形成一系列颇具自身特色的实践特性。前者主要包括规划建设的整体性、合作领域的综合性、参与主体的多元性和互动层次的跨域性等;后者则主要形成了以湄委会为中心的制度架构和全体一致、共识性决策、共同参与等规范原则,并孕育了以共同目标意识、超越政治分歧的团结意识和合作精神为核心内涵的区域合作"湄公精神"。这些实践特性及规范原则构成二战后新生的区域合作"亚洲方式"的重要组成部分,而后融入东南亚本地区域合作实践进程,成为"东盟方式"的重要规范来源。

下湄公河流域国际组织机构及相应法律文件研究

本文回顾了下湄公河流域合作开发与管理的有关国际组织机构变化，分析了《下湄公河流域持续发展合作协定》诞生及新湄委会成立的背景；对比了该流域有关水资源及相关资源开发利用和管理的法律法规条款变化。

湄公河下游水资源开发与环境保护--各国政策取向与流域治理

作为世界上水资源最为丰富的河流之一,湄公河水电开发一方面符合流域国家的共同利益,通过水电大坝建设促进经济发展的趋势不可避免;但另一方面,下游国家也会长期面临环境保护的压力。如何妥善处理水资源开发与环境保护之间的关系、在上下游国家之间合理分配成本与收益,将成为影响流域国家间关系的重要议题。在水电资源开发与生态环境保护关系问题上,国际社会和业界专家基于不同的立场,并没有达成一致意见。但可以肯定的是,在大坝规划和建设中更加注重保护生态环境,更多地体现受影响群体在利益分享中的诉求已是大势所趋,同时也为大坝建设国和相关行为体的水资源管理能力提出了更高的要求。然而,湄公河下游国家在水资源管理方面仍存在若干不足,阻碍了流域综合治理的实现,主要表现在以下方面:下游各国的利益诉求不甚统一;作为流域唯一的专门水资源管理机构,湄公河委员会的权威性不足;国际非政府组织和域外国家的介入等。中国作为湄公河上游国家,应及时把握下游水电开发的新动向,客观分析下游各国的不同利益诉求,积极参与流域环境保护。

全球治理的区域路径

从经验和规范上看,区域治理已被视作当代全球治理体系的重要组成部分。"大区域观"将通常界定的特定地理区域治理的互动层次向上延伸至区域间或跨区域,据此提出全球治理的三种区域路径:全球治理中的区域治理--区域作为全球治理体系中的一个内部治理层次,即"从外到内的路径";区域治理中的全球治理--全球作为区域治理体系中一个外部治理层次,即"从内到外的路径";全球-地方联结中的区域间治理--新区域作为全球-区域治理体系中的一个新型层次,即"内外融合的路径"。第一种路径的核心力量来自域外行为体,依据的核心制度平台是全球性组织及全球多边机制;第二种路径的核心力量来自域内行为体,依据的核心制度平台是区域组织及区域多边机制;第三种路径的核心力量来自不同区域的区域组织或一组国家,依据的核心制度平台是区域间或跨区域的制度。对湄公河下游早期治理、东南亚气候治理和中国区域间治理等典型案例的分析,揭示了这三种路径的运行机制及其经验合理性。