月球上的"水"

在地球科学的各个领域中,在行星演化学和太空探索中,水都是不可缺少的元素。长久以来,我们一直认为月球是干燥的。然而最新的研究成果推翻了这个观点。近期的遥感探测和撞月实验表明,月球表面不仅含有结构水(OH和H₂O), 而且还有固态冰的存在。对月球火山玻璃和玄武岩的磷灰石重新分析也发现了这些玻璃中的OH,揭示了月球内部有水的存在。这个发现,意味着我们可能需要重新审视现有的月球火山活动和演化的模式。月表水和内部水的存在,还为未来以月球为跳板进行太空探索,提供了重要的资源。这里,我们对月表水和内部水的研究作一总结,并就这些发现的意义展开讨论。     

土在冻结及融化过程中的热力学研究现状与展望

冻胀融沉给工程建设及运营带来了极大的危害,是科研人员及工程建设者迫切需要解决的重大问题. 土在冻结及融化过程中会产生水分迁移、冰水共存、固结和冻结缘等现象,这些现象的产生涉及到冻结及融化过程中冰水相变、冰分凝和水分迁移等关键机制的研究. 目前,冰水相变、冰分凝和水分迁移等机制的研究已成为解决冻胀融沉问题的重点及难点. 冻融过程是建立在热力学基础上关于水分场、应力场及温度场的三场耦合过程,其数值模拟正处于由水-热耦合到水-热-力耦合的演化阶段. 而冻结缘参数的测试和确定是理论探索和数值模拟的关键. 近几十年来,随着实验技术的发展,各种先进的探头及仪器设备被开发应用于冻结及融化过程的室内或者场地试验研究,以期揭示其内部的微结构特征及其热力学机理. 因此,系统地总结和分析土在冻结及融化过程中的现象、机理、试验条件以及数值模拟等工作,将对土冻结及融化过程的认识及研究有着至关重要的作用.     

近40年黄河中游径流情势变化分析

20世纪60年代以来，黄河中游地区一系列大规模人类生产活动如引水灌溉、水土保持等，使得黄河中下游的径流情势在过去的几十年里经历了较大的变化，造成流域水土流失、生态恶化和经济损失严重。本文以黄河中游的岔巴沟流域为例，研究了1959～2000年黄河中游地区人类活动对径流情势的影响。结果表明：流域径流在1978年受到水土保持活动的显著干扰，年径流量减少了30％以上，且径流年际、年内变化均有所减小。此外，流域径流情势随淤地坝有起有落的发展过程出现了一系列相应的变化。     

Numerical simulation of evapotranspiration using a root water uptake model

The abstraction of ground water by vegetation and its influence on the behaviour of geotechnical structures such as pavements, foundations and slopes has been researched for many years. In recent years, the use of numerical methods in geotechnical engineering has rapidly increased. A major challenge for numerical modelers involves the specification of the surface flow boundary condition to model root water uptake by vegetation. The abstraction of ground water by roots is a complex process which involves the interaction of the atmosphere, vegetation and the ground. Accurate prediction of the pore water pressure changes induced by vegetation requires the development of algorithms which can mimic the process of transpiration by vegetation in the continuity equation of fluid flow. This paper presents a root water uptake model which has been coded into a finite element program that can perform coupled (mechanical and fluid flow behaviour) analyses. The input data includes rainfall, potential evapotranspiration and maximum root depth. The key features of the model are discussed first, followed by a presentation of results from a series of parametric studies.     

Water dynamics and population pressure in the Nepalese Himalayas

Water is rapidly becoming a critical factor in the development of Nepal despite the fact that it has one of the greatest hydro-power potentials in the world. The country is faced with three key water issues: hazardous hydro-power development, problems with community water supply and pollution, and shortages of irrigation water. Both the environmental settings and the socio-economic conditions have contributed to these problems which are now widespread and alarming. Environmental factors have not been taken seriously as shown in the largest existing hydropower reservoir, which has recently lost much of its storage capacity in a single unusual storm. Shortages in water supplies in the capital city are also reaching crisis proportions both in terms of quantity and quality. The widespread lack of irrigation water in the Middle Mountains during the dry season has serious implications for the future food supplies of the largely rural population. Some of these problems result from a rapidly expanding population living in a very marginal environment, an ineffective government organization and an international community that is mostly self-serving, focussing on large projects with little concern for local needs. The degradation of water resources is putting the food supplies and health of a large part of the population at risk.     

牛栏江流域水污染特征与水资源保护对策研究

牛栏江—滇池补水工程是滇池流域及周边地区的水资源综合利用工程,是增加滇池生态环境水量,改善滇池水资源质量的重要工程,对于保障现代新昆明建设和云南省经济社会可持续发展具有重大战略意义。然而近年的监测结果表明,牛栏江流域水资源质量有下降趋势。在以往的研究中曾提出面源污染是主要污染源。通过研究,发现牛栏江水污染物以总磷(TP)为主,且主要集中在七星桥断面以上;总磷(TP)污染主要来自于工业排放。并据此提出水污染治理的水资源保护对策。水环境治理措施和水质监测结果验证了结果的可靠性。     

滇中地区缺水成因分析及对策研究

近年来，滇中地区总需水量日益增加，而供水水源始终不能满足需求，水资源供需矛盾日渐突出，严重制约了该地区经济社会的可持续发展。从多角度分析了滇中地区的水资源紧缺及其缺水成因，根据该地区实际情况，研究了缺水问题的一些对策。     

中国非常规水资源开发利用进展

非常规水资源开发利用已成为世界各国缓解水资源危机的重要举措之一。为深化对中国非常规水资源开发利用水平和现状的认知,更好地支撑非常规水资源开发利用管理和实践,在对不同类型非常规水资源开发利用实地调研的基础上,重点阐述非常规水资源的术语和内涵,总结非常规水资源的现状开发利用量和开发利用模式,分析非常规水资源开发利用中存在的主要问题,并针对性地提出对策建议。近年来中国加大了对非常规水资源的开发利用力度,非常规水资源开发利用量逐年上升,截至2018年底已达86.4亿m³,但在全国供水总量中的占比尚不足1.5%,开发利用中还存在体制机制不健全、规划设计不到位、工程技术有短板等问题,制约着非常规水资源开发利用的有序发展。非常规水资源开发利用涉及面广,需要社会各界的共同努力,才能迎来非常规水资源开发利用的新局面。     

Below the radar: the boom of groundwater use in the central part of the Nile Delta in Egypt

The Nile Delta of Egypt is known for its large irrigated area supplied with water diverted from the Nile River, with a limited use of groundwater, largely for domestic and industrial use. Official statistics for the whole delta indicate that there are a few thousand individual wells used for agriculture by a population of over 2 million farmers. This study, however, shows that a phenomenon of groundwater development for irrigation has been unfolding over the last few years, largely below the radar of managers and researchers. A survey was carried out in the central part of the delta with the objective of (1) uncovering the actual situation of groundwater use in this part of the delta and (2) speculating on its implications. The results of the survey pointed to a recent and booming tube-well drilling industry, with well densities in some parts reaching one well every 2 ha. The development of groundwater abstraction in the central delta is strongly linked to inadequate and/or untimely availability of surface water in the canals. A technical, economic, and management characterization of wells complements the study, showing a continuum between purely private/individual ownership of wells and collective investments and management. Lastly, the article explores the implications of unchecked abstraction at the farm, local and delta scales.     

中国非常规水资源开发利用进展

非常规水资源开发利用已成为世界各国缓解水资源危机的重要举措之一。为深化对中国非常规水资源开发利用水平和现状的认知,更好地支撑非常规水资源开发利用管理和实践,在对不同类型非常规水资源开发利用实地调研的基础上,重点阐述非常规水资源的术语和内涵,总结非常规水资源的现状开发利用量和开发利用模式,分析非常规水资源开发利用中存在的主要问题,并针对性地提出对策建议。近年来中国加大了对非常规水资源的开发利用力度,非常规水资源开发利用量逐年上升,截至2018年底已达86.4亿m3,但在全国供水总量中的占比尚不足1.5%,开发利用中还存在体制机制不健全、规划设计不到位、工程技术有短板等问题,制约着非常规水资源开发利用的有序发展。非常规水资源开发利用涉及面广,需要社会各界的共同努力,才能迎来非常规水资源开发利用的新局面。     

Population and resource crisis: A Kenyan case study

In recent years the population/development debate has shifted to consideration of the adequacy of resources to meet the accelerating population growth especially in developing countries. In the second area of concern the problem has been the adverse impact of the rate of population growth on availability of land.The history of Kenya's population growth clearly shows a steep rise from just after World War II to the late 1970s. In quantitative terms the rate of population growth has increased from just about 2% per annum to almost 4% per annum. The cause of the accelerated growth of population lies in the rising fertility and in particular to the sharp reduction in mortality and foetal loss as a result of development process.The rise in growth rate has taken place at different rates in accordance with limited areas of medium and low potential land. The implications of the spatial differential rates of growth include a significant decline in land availability and acceleration in the rate of soil loss. Equally more important is pressure on available water and wood fuel resources.In terms of policy options, Kenya must accommodate itself to continued acceleration of population growth and increasing pressure on land resources. The policy options include a rise of land in the main productive heartland of the country and water management policy that will permit an enlargement of agricultural land in the semi-arid and arid zones which constitute almost 2/3 of the land area. However, a permanent solution must rely in development of human resources and in the moderation of population growth.     

Clustering of groundwater chemistry data with implications for reservoir appraisal in West Siberia

Division of sedimentary strata according to groundwater chemistry is discussed with implications for petroleum reservoir potential. It is suggested to process multiparametric water chemistry data from West Siberia using formalized clustering techniques. The efficiency of this approach has been tested for Neocomian clinoform reservoirs with reference to regional-scale appraisal and subregional petroleum division.     

Water level fluctuations due to earthquakes in Koyna-Warna region,India

Earthquakes cause a variety of hydrological phenomena, including changes in the ground water levels in bore wells. The Koyna region in the peninsular shield of India, hitherto considered stable in terms of seismic activity, has been active since 1967. More recently, the earthquakes have been localized to the newly impounded Warna reservoir, which is located south of Koyna, where a burst of seismicity occurred in 1993. The region continues to remain seismically active even after four decades. Twenty-one bore wells were drilled around the seismic source volume in the region to observe water level changes resulting from earthquake phenomena. Our studies have shown coseismic anomalous water level changes to be associated with the moderate earthquakes of April 25, 1997 and February 11, 1998. Our results show that changes in the ground water level in bore wells are correlated with micro-earthquake activity, both preceding and following moderately sized earthquakes. The results have implications in enhancing our understanding of earthquake mechanisms.     

The research of groundwater flow model in Ejina Basin,Northwestern China

Water resources is a primary controlling factor for economical development and ecological environmental protection in the inland river basins of arid western China. Groundwater, as the important component of total water resources, plays a dominant role in the development of western China. In recent years, with the utilization ratio of surface water raised, the groundwater recharge rate has been reduced by surface water, and groundwater was exploited on a large-scale. This has led to the decline of groundwater levels and the degradation of eco-environments in the lower reaches of Heihe watershed, especially. Therefore, the study on the groundwater-level change in recent years, as well as simulating and predicting groundwater levels changes in the future is very significant to improve the ecological environment of the Heihe River Basin, coordinate the water contradiction, and allocate the water resources. The purpose of this study is to analyze the groundwater-level variations of the Ejina region basin on a large-scale, to develop and evaluate a conceptual groundwater model in Ejina Basin; according to the experimental observation data, to establish the groundwater flow model combining MODFLOW and GIS Software; simulated the regional hydrologic regime in recent 10 years and compared with various delivery scenarios from midstream; determined which one would be the best plan for maintaining and recovering the groundwater levels and increasing the area of Ejina Oasis. Finally, this paper discusses the possible vegetation changes of Ejina Basin in the future.     

淮南潘谢矿区岩溶类地质异常体演化过程及预测

针对深埋矿山开采岩溶通道的突水致灾问题,依据近年淮南潘谢矿区揭露资料,讨论了该区岩溶类"地质异常体"特征;在分析宏观地质背景基础上,从沉积史、构造史、古岩溶发育史及地下水流作用等方面追踪其演变过程;通过分析古地貌与矿区不同深度放水试验水文地质特征,间接分析深埋条件下的古岩溶信息,并预测潘谢矿区岩溶类"地质异常体"分布位置,从而为煤炭开采过程中的灰岩水害防治提供参考。      

Investigation of lake drying attributed to climate change

In recent decades, climate change has been of great concern due to its effect on water level and its impact on aquatic ecosystems. Urmia Lake, the largest inland wetland in Iran, has been shrinking. There is a great concern whether it will dry up like the Aral Sea. Therefore, a hydrodynamic model has been developed to simulate the condition of Urmia Lake. The model has been validated using the known annual data on precipitation, evaporation, run off, river discharges and water level which are available for the last 35?years. Different hydrological conditions regarding lake input and output data were tested and water depth was calculated using bathymetry to predict water-level fluctuations in the future. The results predict that the water level will decrease continuously. The lake will be dried up in about 10?years if very dry conditions continue in the region. The drought speed cannot be reduced and there is no potential to develop a water-usage program. Besides, the lake water depth decrease is more slightly, applying alternate wet and dry-period conditions. In some hydrological conditions there is a good potential to consider water development projects. The sensitivity analysis of different parameters indicates that the lake is highly sensitive to river discharges, which implies that the water development project plans will disturb the lake ecosystem if implemented up to 2021 and integrated watershed management plan for the lake can change the condition by regulating the dam output.     

Groundwater overuse and farm-level technical inefficiency: evidence from Sri Lanka

Extraction of groundwater for onion and other cash crop production has been increasing rapidly during the last two decades in the dry zone areas of Sri Lanka. As a result of overuse, the quantity of available groundwater is gradually declining, while water quality is deteriorating. The deteriorating water quality has a negative impact on agricultural production, especially for crops (such as onions) that are sensitive to increases in salinity levels. This issue is examined with respect to onion production in Sri Lanka. A stochastic frontier production function (SFPF) is used, in which technical efficiency and the determinants of inefficiencies are estimated simultaneously. The results show that farmers are overusing groundwater in their onion cultivation, which has resulted in decreasing yields. Factors contributing to inefficiency in production are also identified. The results have important policy implications.