世界水日、中国水周主题下的水资源发展回顾与展望

基于历年世界水日、中国水周主题及其变化热点,梳理水资源在自然环境、人类社会生活中的现实发展变化情况;分析水资源在现代社会可持续发展中的作用,展现水资源科学发展的时代强音;论述当前全球对水资源的管理和保护措施,世界水日主题变化呈现由人类出发到人类与自然和谐共处的趋势,中国水周主题变化始终与政府宏观水资源的政策相关;世界水日与中国水周发展进程中,人类与水资源和谐共处的生态思想逐渐体现,显示了世界范围内人与自然和谐相处的理念逐渐深入人心。     

Recent warming of Tonle Sap Lake,Cambodia: Implications for one of the world’s most productive inland fisheries

Tonle Sap Lake in Cambodia is arguably the world's most productive freshwater ecosystems, as well as the dominant source of animal protein for the country. The rapid rise of hydropower schemes, deforestation, land development and climate change impacts in the Mekong River Basin, however, now represent serious concerns in regard to Tonle Sap Lake's ecological health and its role in future food security. To this end, the present study identifies significant recent warming of lake temperature and discusses how each of these anthropogenic perturbations in Tonle Sap's floodplain and the Mekong River Basin may be influencing this trend. The lake's dry season monthly average temperature increased by 0.03°C/year between 1988 and 2018, being largely in synchrony with warming trends of the local air temperature and upstream rivers. The impacts of deforestation and agriculture development in the lake's floodplain also exhibited a high correlation with an increased number of warm days observed in the lake, particularly in its southeast region (agriculture R² = .61; deforestation R² = .39). A total of 79 dams, resulting in 72 km³ of volumetric water capacity, were constructed between 2003 and 2018 in the Mekong River Basin. This dam development coincided with a decreasing trend in the number of dry season warm days per year in the lower Mekong River, while Tonle Sap Lake's number of dry season warm days continued to increase during this same period. The present study revealed that Tonle Sap Lake's temperature trends are highly influenced by temperature trends in the local climate, agriculture development and deforestation of the lake's watershed. Although there were no noticeable impacts observed from upstream dam development in the Mekong River Basin, local‐to‐regional agricultural and land management of the lake's watershed appear to be effective strategies for maintaining a stable thermal regime in the lake in order to facilitate maximum ecosystem health.     

国家自然科学基金项目（51769017、51969018）

针对现有碾压混凝土坝温度场预警多是基于单个测点进行分析这一不足,提出了利用多测点综合信息预警的模式和方法。采用概率原理对温度监测值的有序度和无序度进行了定义,基于投影追踪法,确定了各测点的权重分布;根据温度场有序到无序的演变规律,结合有序度和测点权重分布,构建了能描述碾压混凝土坝温度场有序性的权重熵;借助典型小概率原理,提出了碾压混凝土坝温度场预警准则。实例分析表明：权重熵的变化规律与温度实测值变化规律相吻合,从而验证了该方法的可行性和有效性。     

高温气候下沥青混凝土心墙连续碾压施工结合面温控试验研究

在夏季高温气候沥青混凝土心墙连续多层施工时,为减少等待结合面温度降至规范要求上限值90℃的时间,通过室内试验模拟结合面温度提高后心墙连续两层铺筑的情况,分别研究了结合面温度在90℃、100℃、110℃情况下沥青混凝土的压实性和变形情况,并进行了现场试验论证。室内试验结果表明:心墙沥青混凝土结合面温度降至100℃时,上层沥青混凝土的孔隙率为2.88%,下层沥青混凝土的最大侧向应变值为2.78%;结合面温度为110℃时,上层沥青混凝土的孔隙率为3.85%,下层沥青混凝土的最大侧向应变值为4.00%。现场试验结果表明:结合面温度为100℃时的上层沥青混凝土孔隙率和渗透系数均满足规范要求。因此,沥青混凝土心墙连续多层碾压时,结合面温度提高至100℃的施工质量可以得到保证。     

Quantifying water quality and flow in multi-branched urban estuaries for a rainfall event with mass balance method

In this study, field observations were conducted after a heavy rainfall event in the Sumida and Shakujii rivers in Tokyo, Japan. The flow dynamics and fluxes of salt, suspended sediment (SS), and dissolved oxygen (DO) were investigated with the mass balance method. The fractions of fresh water and saltwater in seaward and landward flows were separated. The maximum salt flux in the Shakujii River was 53.8 kg/s during the flood tide, and those in the Sumida River were 680.3 kg/s at the upstream station and 703.7 kg/s at the downstream station. The trends of SS and DO fluxes were similar in both rivers. In the Shakujii River, the highest SS (3.1 kg/s) and DO (0.4 kg/s) fluxes appeared during the flood tide after rainfall. In the Sumida River, the maximum SS fluxes (6.1 and 6.3 kg/s at the upstream and downstream stations, respectively) and DO fluxes (1.15 and 1.21 kg/s at the upstream and downstream stations, respectively) appeared during the ebb tide. The mass balance method was used to estimate discharge, salinity, SS concentration, and DO concentration at a station with missing data. The results show that the estimated salinity and SS concentration had a significant correlation with the on-site observations, with correlation coefficients (R) of 0.950 and 0.835, respectively, but not for DO concentration (R = 0.638). The disparity between the computed and measured data may be explained by the differences in velocity, salinity, topography, sedimentation, and the presence of organic matter. The analysis based on the advective salt transport components found a lower salt flux per unit width in the Shakujii River (0.36 kg/(m·s)) in comparison with that in the Sumida River (2.88 kg/(m·s)). This indicates a higher probability for salt retention in the Shakujii River.     

大宁调蓄水库蓄水后生态环境效益分析

南水北调工程的建成通水,改变了北京城市供水格局,给北京带来了巨大的效益,生态环境效益就是其中重要一环。分析北京市南水北调配套工程生态环境效益的组成,科学地计算和评估生态效益,对于未来北京市南水北调配套工程效益的发挥、工程的运行管理、首都水务事业的发展有着重要意义,大宁调蓄水库是北京市南水北调配套工程之一,经计算,大宁调蓄水库蓄水后生态环境总效益为34176.29万元。计算方法也可为类似工程生态环境效益的估算提供参考。     

不同初始损伤白砂岩高温处理后的力学性能研究

通过进行不同初始损伤程度白砂岩在不同等级高温处理后的力学试验,分析了温度和初始损伤对白砂岩的杨氏模量、峰值应力和显微结构等方面的影响。试验结果表明:随着温度的升高,受到初始损伤的白砂岩试件的杨氏模量和抗压强度都呈下降的趋势,初始损伤越大,高温对白砂岩造成的影响越大。通过显微镜观察到随着温度的升高,试块的晶体变小,颗粒的破坏更为破碎,岩屑更多。此外,通过对试验数据的整理,建立了不同初始损伤等级和不同温度等级下白砂岩的本构关系曲线。     

国内外水资源承载力的研究综述

随着能源危机的出现,资源环境问题逐渐成为各国经济学家和环境学家特别关注的问题.近年来,水资源短缺越来越成为各地经济发展的制约因素,面对这种情况,资源承载力概念的提出为资源与经济发展问题提供了一条新的研究途径.本文将国内外有关水资源承载力概念和量化方法的研究作一总体分析,结果表明:(1)国外对水资源承载力的研究较少,国内的研究大体可分为初始、发展、鼎盛和拓展四个阶段;(2)从横向比较来看,水资源承载力的研究在我国以近十年为盛.但研究多集中在资源学科领域和地理环境学科领域,角度大多是综合考虑多方面的影响因素,对一个地区的水资源承载力作出系统评价,并借助可持续发展的思想,应用已有的和创新的方法来解决水资源承载力的问题;(3)水资源承载力的研究在一定程度上是土地资源承载力研究的进步;(4)水资源承载力的研究较少考虑环境污染对水资源承载力以及整个社会系统的影响.在此基础上,本文最后对承载力在自然资源方面的研究作了小结和展望.     

Water accounting for the Orange River Basin: An economic perspective on managing a transboundary resource

The framework for water accounting is applied to an international river basin, the Orange River Basin, which is shared among Botswana, Namibia, Lesotho and South Africa. Each of the riparian states faces water constraints and relies increasingly on shared international water resources. The countries have adopted the principle of an economic approach to water management, once basin human needs are met, and all but Lesotho have constructed national water accounts to assist in water management. The water accounts for the Orange River Basin bring an economic perspective to water management at the regional level. The accounts include supply and use tables, which are used to compare the contribution to water supply from each riparian state to the amount used. The water accounts are then linked to economic data for each country to calculate water use and productivity by industry and country. There are considerable disparities in water productivity among the countries, which should be taken into account in future decisions about water allocation, pricing and infrastructure development.