南水北调西线工程的几个科学问题

南水北调西线工程区的地质构造非常复杂,可以说这项工程相当于在"太岁头上动土".从现有的研究和论证上看,我们都回避了一个未来变化的问题,而研究未来的变化和对我们所产生的影响、特别是对环境敏感区的影响是我们必须面对的.     

昆明松华坝水源地水沙特征及变化趋势分析

径流与输沙变化是水源地健康的重要表征。利用昆明松华坝水源地中和水文站1961-2011年径流和1966-2011年输沙数据,运用集中度与集中期、R/S分析等方法,对松华坝水源地径流和输沙变化、年内分配及未来趋势变化进行了定量分析。结果表明:径流和输沙均呈下降趋势,2009-2011年连续干旱导致径流和输沙骤减;输沙年内分配集中度高于径流,径流和输沙年内分配集中度分别呈下降和上升趋势;径流和输沙分别出现26和24年的长周期,径流和输沙多年平均集中期分别出现在8月中旬和上旬,且均呈提前趋势;径流未来仍将延续下降趋势,但趋势性不强,输沙未来变化趋势具有不确定性;径流和输沙年内分配集中度仍将分别延续下降和上升的趋势,且输沙年内分配未来变化的趋势性更强。     

英国关于未来气候变化的报告

英国关于气候变化对水资源影响的研究报告指出，由于CO2排放量增加，未来80年内温度、降水、土壤温度等条件将发生变化。气候条件的变化使来水条件也将发生很大变化。我国也参与了气候变化的研究报告编制，但还没有形成系统、完整的研究气候变化对水资源影响趋势的成果。了解英国的报告结果，有助于我们重视气候变化对水资源影响的趋势。     

变化环境下径流演变的研究方法进展

气候变化和人类活动的双重影响使流域天然径流序列发生时空演变。对变化环境背景下径流序列演变规律、驱动因素的研究及在不同气候模式下对未来径流的预估对流域水资源管理和长期规划具有重要意义。为此对当前变化环境下径流演变趋势检验、径流变化归因分析及未来径流趋势预估的相关研究方法进行了全面的回顾,并进行综合对比分析。结果表明：采用多种检验方法组合优于单一检验,其结果更为可靠;气候变化和人类活动影响程度在不同流域、不同时期差异较大;未来径流预估结果的不确定性源于气候模式、水文模型和降尺度方法等多个方面。研究结果可为变化环境下径流演变及其驱动因素的研究提供新思路和科学参考。     

内蒙古干旱研究进展

内蒙古频发的干旱制约着本区域社会经济发展与生态环境安全,摸清其研究现状可为本区域干旱防御与未来研究的方向提供参考。本研究采用文献综述的方式,对近20年300余篇相关文献进行了梳理。研究发现:内蒙古干旱研究集中于时空演变特征、形成机理、自然与社会影响、干旱监测与预警、干旱治理和风险管理等6个方面;各类干旱指标在不同自然区域的适宜性基本得以厘清,同时揭示了干旱频发且严重地区的成因、影响及治理措施,初步形成了有效的干旱监测和风险管理体系;但缺乏对极端干旱动态过程及其对牧草、牲畜、牧民收入等方面影响研究,面向牧区的精细化干旱监测与预警模式有待建立,干旱对农业生产影响的研究较为薄弱,区域内干旱风险评估过程与指标缺乏标准。本研究明确了以往内蒙古干旱研究的侧重点和未来需深入探究的方向,可为后续相关研究的开展和科学制定干旱防御政策提供参考。     

气候变化和人类活动对水文循环影响研究进展

气候变化和人类活动是影响流域水文循环过程和水资源演变规律的两大驱动因素,所引起的水文效应已成为当前全球变化研究领域的焦点问题。水循环系统是气候系统的重要组成部分,气候变化对水循环要素的影响必然导致流域水资源的时空变化。同时,人类活动对流域水循环的影响也日益显著,主要表现为土地利用/覆被变化、修建大型水利工程等引起的流域下垫面条件变化,进而影响流域内的产汇流机制。针对气候变化和人类活动对流域水循环要素的影响机制,从水文要素时空变化检测与归因的角度对主要研究结果进行回顾,探讨了变化环境下水循环要素变化的检测与归因分析研究方法,并总结了定量区分气候变化和人类活动对水循环过程影响研究中的主要问题和不足,提出了未来需要重点加强气候变化和人类活动对水循环要素变异的驱动机理及贡献分解研究、加强水循环要素时空变异特征的诊断以及模型评价技术和不确定性量化研究等。     

桃林口水库运行期环境影响分析与探讨

随着社会经济的快速发展,环境问题将是制约社会可持续发展的重要因素之一。大型水利枢纽工程对环境的影响一直受到社会的关注,本文对桃林口水库运行初期环境影响问题进行了分析和对未来影响进行了探讨。     

北洛河流域水沙变化对降雨和土地利用的响应

研究流域水沙变化对降雨和土地利用变化的响应机理,对流域土地利用规划决策及水土保持措施优化配置具有重要意义。本文以黄土高原北洛河流域为研究对象,采用Pettitt突变检验、双累积曲线等方法,定量分析了流域近60年降雨、径流和输沙的演变规律及土地利用变化特征,探讨了流域降雨和土地利用变化对流域水沙的影响。结果表明:1960—2016年间,北洛河流域降雨随时间变化总体趋势不显著,而径流量和输沙量随时间变化表现为明显的下降趋势,下降幅度分别为31.4%和83.5%,输沙量减少趋势尤为显著;研究时段内,北洛河流域以林地、草地和耕地为景观基质,耕地、草地向林地转化是基本特征;人类活动影响下的土地利用变化是造成径流泥沙量减少的主要原因,其对径流输沙量减少贡献率分别为76.9%和96.6%,降雨变化影响贡献率分别为23.1%和3.4%。研究结果为深刻认识黄河水沙动态变化提供依据,对未来水土保持措施优化配置提供决策支撑。     

乌鲁木齐市经济社会用水结构变化及未来趋势分析

分析城市用水结构的变化并科学预测未来需水结构,是编制水资源利用规划的前提和基础,对区域水资源的合理配置具有重要意义。在分析乌鲁木齐市社会经济各业用结构变化及其规律的基础上,探讨了其变化的主要原因,并预测了未来用水结构的发展趋势及其对未来水资源供需形势的影响,对协调未来可能利用水资源与社会经济发展的关系、制定合理的水资源配置方案、促进经济社会可持续发展提供参考。     

河流低流量对土地利用/覆盖变化的响应研究综述

随着人类活动的加剧,土地利用/覆盖变化对水资源影响的问题日益突出,已经越来越受到国际上的重视,成为当今研究的重要课题。目前在国内,土地利用变化/覆被变化导致径流平均流量变化这一方面研究较多,但是,低流量对土地利用/覆盖变化的响应研究还鲜有报道。因此,本文以我国土地利用变化趋势为基础,通过城市化、森林植被变化以及未来土地利用变化三个角度来阐述不同的土地利用变化对低流量的影响。     

Over-exploitation of groundwater resources and their environmental and socio-economic implications: the case of Jordan

Jordan is overusing its groundwater resources stocks. The present impacts on the groundwater itself are manifested in the drop in groundwater levels, reduction in or ceasing of spring discharges, saltwater intrusions and deteriorating water quality. The socio-economic impacts are results of reduced water quality and quantity. The negative impacts, both on the groundwater resources as such, and on socio-economics are expected to intensify with the passage of time. Rethinking in the management of the water sector has become very essential and radical changes towards a balanced resources/demand equation have become inevitable for a continual yield of water resources to guarantee future generations equity in these resources.     

The Impacts of Climate Variability and Future Climate Change in the Nile Basin on Water Resources in Egypt

This paper describes the application of hydrologic models of the Blue Nile and Lake Victoria sub-basins to assess the magnitude of potential impacts of climate change on Main Nile discharge. The models are calibrated to simulate historical observed runoff and then driven with the temperature and precipitation changes from three general circulation model (GCM) climate scenarios. The differences in the resulting magnitude and direction of changes in runoff highlight the inter-model differences in future climate change scenarios. A 'wet' case, 'dry' case and composite case produced +15 (+12), -9 (-9) and + 1(+7) per cent changes in mean annual Blue Nile (Lake Victoria) runoff for 2025, respectively. These figures are used to estimate changes in the availability of Nile water in Egypt by making assumptions about the runoff response in the other Nile sub-basins and the continued use of the Nile Waters Agreement. Comparison of these availability scenarios with demand projections for Egypt show a slight surplus of water in 2025 with and without climate change. If, however, water demand for desert reclamation is taken into account then water deficits occur for the present-day situation and also 2025 with ('dry' case GCM only) and without climate change. A revision of Egypt's allocation of Nile water based on the recent low-flow decade-mean flows of the Nile (1981-90) shows that during this period Egypt's water use actually exceeded availability. The magnitude of 'natural' fluctuations in discharge therefore has very important consequences for water resource management regardless of future climate change.     

Impacts of different weed cutting practices on macrophyte species diversity and composition in a Danish stream

Various effects of stream management on biotic communities have been suggested on the basis of observations and investigations in regularly managed streams throughout Europe, but only very sparse information is available about if and how stream management can be combined with maintaining a natural and diverse stream flora. Our study was carried out to investigate how weed cutting practice and frequency can affect macrophyte communities to provide knowledge for future decisions regarding management in streams. We chose an experimental approach and applied four different weed cutting practices (cutting full width, central channel, diagonal channels and no cutting) and frequencies within one stream reach for four years. We found only very limited changes over the four years in overall macrophyte diversity parameters following different management practices and there were no changes in macrophyte diversity parameters either as a function of the weed cutting frequency or method applied. In contrast we found directional changes in macrophyte composition following frequent cuttings of either the whole stream channel or a less comprehensive cutting of only one central channel for four years. In both cases the macrophyte communities changed towards a more Ranunculus dominated community while Potamogeton natans became less important in the community. This change seemed to reflect a higher tolerance of Ranunculus towards disturbance. On the basis of these results, we recommend that the management frequency in streams is limited and, if several cuttings are needed to prevent bank over‐flow, cutting in several narrow channels is preferable to cutting in one central channel as directional changes in plant communities are avoided. Copyright © 2003 John Wiley & Sons, Ltd.     

Quantification of Expected Changes in Peak Flow Quantiles in Climate Change by Combining Continuous Hydrological Modelling with the Modified Curve Number Method

Climate projections point to modifications in the magnitude, frequency and timing of floods in the future. However, robust methodologies to quantify how climate change will modify the catchment response in flood events are required. Continuous hydrological modelling usually smooth magnitudes of extreme events. This paper proposes a methodology to improve the assessment of flood changes in the future driven by climate change. Climate change projections of the EURO-CORDEX programme obtained under the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) supplied are used. Four catchments located on the Douro River Basin have been considered as case studies. Precipitation and temperature projections have been bias corrected to reduce errors with observations in the control period (1971–2004). The HBV continuous hydrological simulation model has been used to simulate the soil moisture content on the day of occurrence of the maximum annual rainfalls in the four catchments. The modified curve number method has been utilized to obtain the changes expected in the future in flood magnitudes, considering the initial soil moisture contents estimated with the HBV model and the expected changes in annual maximum rainfalls. The methodology has been applied to the control period (1971–2004) to check the validity of the process. Then, the methodology has been applied to the future period (2011–2095), to quantify the changes expected in the future in flood magnitudes under climate change conditions. The combined use of the HBV continuous hydrological simulation with the modified curve number method improves the results provided by the HBV model. The proposed methodology allows a better characterization of the response of catchments in flood events. It also considers the expected variation in the antecedent moisture content in catchments in the future, driven by increasing temperatures and decreasing mean annual precipitations in the future. The results show that flood quantiles will increase in three of the four catchments considered.

     

Flow regime alterations under changing climate in two river basins: implications for freshwater ecosystems

We examined impacts of future climate scenarios on flow regimes and how predicted changes might affect river ecosystems. We examined two case studies: Cle Elum River, Washington, and Chattahoochee–Apalachicola River Basin, Georgia and Florida. These rivers had available downscaled global circulation model (GCM) data and allowed us to analyse the effects of future climate scenarios on rivers with (1) different hydrographs, (2) high future water demands, and (3) a river–floodplain system. We compared observed flow regimes to those predicted under future climate scenarios to describe the extent and type of changes predicted to occur. Daily stream flow under future climate scenarios was created by either statistically downscaling GCMs (Cle Elum) or creating a regression model between climatological parameters predicted from GCMs and stream flow (Chattahoochee–Apalachicola). Flow regimes were examined for changes from current conditions with respect to ecologically relevant features including the magnitude and timing of minimum and maximum flows. The Cle Elum's hydrograph under future climate scenarios showed a dramatic shift in the timing of peak flows and lower low flow of a longer duration. These changes could mean higher summer water temperatures, lower summer dissolved oxygen, and reduced survival of larval fishes. The Chattahoochee–Apalachicola basin is heavily impacted by dams and water withdrawals for human consumption; therefore, we made comparisons between pre‐large dam conditions, current conditions, current conditions with future demand, and future climate scenarios with future demand to separate climate change effects and other anthropogenic impacts. Dam construction, future climate, and future demand decreased the flow variability of the river. In addition, minimum flows were lower under future climate scenarios. These changes could decrease the connectivity of the channel and the floodplain, decrease habitat availability, and potentially lower the ability of the river to assimilate wastewater treatment plant effluent. Our study illustrates the types of changes that river ecosystems might experience under future climates. Copyright © 2005 John Wiley & Sons, Ltd.     

IDENTIFYING SENSITIVE INDICES IN THE RESPONSE OF AQUATIC BIOTA TO LANDSCAPE PATTERN CHANGES: A CASE STUDY OF THE TAIZI RIVER BASIN IN NORTH CHINA

It is widely accepted that riverine ecosystems are influenced by the landscape pattern changes of their corresponding watersheds, but few studies have identified the most sensitive and nonsensitive biotic indices, the most influential landscape metrics and the relationship between aquatic biota and landscape patterns. To address this problem, Taizi river basin of Northeast China is taken as a case study, in which GIS technology and landscape ecology method are adopted. The study is performed at both the basin scale (entire drainage area upstream from certain sample point) and the riparian scale (a certain width buffer on each side of sample point extending the length of drainage network) to direct future landscape pattern design at the corresponding scales. The results show that at the basin scale, the species richness of benthic macroinvertebrate (B‐S) and the fish index of biotic integrity (F‐IBI) are the most sensitive biotic indices to landscape metrics, whereas the species richness of phytoplankton (P‐S), the Shannon–Weaver diversity index of phytoplankton (P‐H), zooplankton (Z‐H), benthic macroinvertebrate (B‐H) and fish density (F‐D) are not sensitive to landscape pattern changes; at the riparian scale, F‐IBI, B‐S and zooplankton density (Z‐D) have significant correlations with 9 of 10 landscape metrics calculated in this study, whereas P‐S, P‐H, Z‐H, B‐H, F‐D and species richness of fish have very low correlations with riparian landscape pattern changes. At the basin scale, no landscape pattern metrics show obviously more influence on the riverine ecosystems than other metrics. At the riparian scale, Shannon's diversity index is a very influential factor. As to both of the two scales, B‐S and F‐IBI are correlated with most landscape metrics. The information derived above can help understand the impacts of landscape change on river ecosystems more clearly and provide useful scientific information on river ecosystem protection from the viewpoint of landscape. Copyright © 2013 John Wiley & Sons, Ltd.     

大海波水库运行管理实践及探索

本文结合大海波水库径流面积大、入库洪水峰量大和泥沙大、径流区建筑物多等特点和水库除险加固前后工程特性变化,总结了多年来该水库大坝运行管理方面的实践经验,提出了今后工程运行中面临的问题和建议,以期为今后工程安全运行与管理提供参考。     

长江下游张南上浅区航道整治效果评价

张家洲南港上浅区是长江下游著名的浅险水道之一,实施航道整治工程前,水道枯水期航道条件恶劣,航道浅情和船舶事故频发,通航安全难以保证,航道建设、管理与维护难度大。介绍了张家洲水道基本情况和航道整治工程概况,分析了张家洲南港上浅区航道整治工程前后河势条件、航道条件的变化以及整治建筑物的稳定性,对工程方案、工程结构型式及工程实施综合效果进行了评价,总结了工程实施的经验,并对整治工程的后续维护与管理提出了建议。分析认为工程实施后,河势格局更趋稳定,南、北港汊道分流比变化不大,4 m线全线贯通,5 m线间断长度明显缩短,水深年际波动趋于稳定,通航条件明显改善,对下浅区的冲淤影响不大,整治建筑物总体保持稳定,达到了预期整治目标,完全能够满足4.5 m×200 m×1 050 m的航道设计标准。     

Enhancing urban infrastructure investment planning practices for a changing climate.

Climate change raises many concerns for urban water management because of the effects on all aspects of the hydrological cycle. Urban water infrastructure has traditionally been designed using historical observations and assuming stationary climatic conditions. The capability of this infrastructure, whether for storm-water drainage, or water supply, may be over- or under-designed for future climatic conditions. In particular, changes in the frequency and intensity of extreme rainfall events will have the most acute effect on storm-water drainage systems. Therefore, it is necessary to take future climatic conditions into consideration in engineering designs in order to enhance water infrastructure investment planning practices in a long time horizon. This paper provides the initial results of a study that is examining ways to enhance urban infrastructure investment planning practices against changes in hydrologic regimes for a changing climate. Design storms and intensity-duration-frequency curves that are used in the engineering design of storm-water drainage systems are developed under future climatic conditions by empirically adjusting the general circulation model output, and using the Gumbel distribution and the Chicago method. Simulations are then performed on an existing storm-water drainage system from NE Calgary to investigate the resiliency of the system under climate change.