退化河流滨岸带生态系统的修复及评价研究进展

退化河流滨岸带生态系统修复及其评价是目前国内外学者研究的热点,也是修复生态学、流域生态学等学科研究的重要内容之一。河流滨岸带生态修复工作的开展必须建立在掌握滨岸带结构及其生态功能的基础上。河流滨岸带生态系统退化成因和驱动机制研究是进行滨岸带生态修复工作的前提;生态系统修复是滨岸带研究的重点和关键,必须遵循自然法则,以修复生态功能为最终目标;河流滨岸带生态系统的修复过程和效果应该建立适宜的评价方法和管理策略来确定。加强河流滨岸带退化机制的理论研究及3S技术的应用,从景观和流域尺度开展滨岸带生态修复的研究和实践工作,着重进行平原河网地区河流滨岸带生态修复的研究和实践工作等将是中国今后相关研究的重点。     

江苏省太湖流域水功能区纳污能力及限制排污总量研究

水功能区纳污能力及限制排污总量研究是制定区域水污染控制规划的基础。依据《江苏省地表水(环境)功能区划》,结合江苏省太湖流域现状水质和污染概况,针对河网区和湖库区分别采用一维、二维非稳态模型,计算江苏省太湖流域水功能区纳污能力,在此基础上,引入最大污染物入河量,核定50%、75%和90%水文保证率下的最大污染物入河量分别为2015年、2020年和2030年限排总量。结果表明:(1)CODMn和氨氮纳污能力分别为284 803 t/a和22 448 t/a;(2)2015年CODMn和氨氮限排总量分别为221 867 t/a和20 520 t/a,2020年和2030年限排总量递减,均小于纳污能力;(3)CODMn和氨氮入河量削减率分别为21.8%和46.3%,与水质超标率相差均在25%以内,基本相符。江苏省太湖流域纳污能力、限排总量、污染物入河量削减率和水质超标率之间关系合理,计算结果合理。研究成果为太湖流域水环境控制规划提供决策依据。     

基于地貌指数的汶川地震灾区单沟泥石流总量计算方法

现行的泥石流总量计算方法普遍存在计算参数较难获取或难以精确获取的问题,加上汶川地震灾区沟谷内分布大量的由崩塌、滑坡体等形成的固体松散物质;所以多数泥石流总量计算公式在汶川震区存在局限性.参考适用于以崩塌、滑坡体为主要物源的泥石流总量计算公式;分析研究区范围内地形地貌发育状态与降雨因素及其地质条件之间的影响关系;将地貌指数(Strahler积分)应用于泥石流总量计算,尝试解决缺乏降雨数据情况下泥石流总量计算问题.根据“8.13”四川清平群发性泥石流数据初步回归分析得到适合于汶川震区的泥石流总量计算模型.     

破碎带对地下坑道动力响应影响的数值分析

为了研究破碎带的耗能作用及其对坑道结构动力响应的影响,根据某工程实例,建立了地冲击波作用下类岩体中坑道结构响应的计算模型,利用LS-DYNA3D有限元软件,分别计算了无破碎带和存在破碎带情况下坑道结构的动力响应。计算结果的对比分析表明,顶部破碎带使结构的加速度和位移等运动参数有不同程度的降低,但对结构所受到的应力影响不大;与之相反,侧部破碎带的存在使结构的加速度和位移等运动参数明显地增大。与顶部存在破碎带情况相比,侧部存在破碎带情况下坑道结构运动参数的峰值更大,对坑道结构安全更为不利。     

高台位旱地石灰性紫色土培肥研究

本文研究了高台位旱地石灰性紫色土的肥力退化因子,并针对紫色母岩矿质养分丰富、易风化成土的特点,以一种培肥耕作法-聚土免耕耕作法培肥土壤。结果表明,采用此耕作法的土壤具有防蚀、抗旱、培肥和自调能力,能提高系统生产力。     

Domestic water conservation potential in Saudi Arabia

Domestic water conservation in arid climates can result in efficient utilization of existing water supplies. The impacts of conservation measures such as the installation of water-saving devices, water metering and pricing schemes, water rationing and public awareness programs, strict plumbing codes, penalties for wasting water, programs designed to reduce leakage from public water lines and within the home, water-efficient landscaping, economic and ethical incentives are addressed in detail. Cost savings in arid climates, with particular reference to Saudi Arabia, in relation to some conservation techniques, are presented. Water conservation technology and tentative demonstration and implementation of water conservation programs are discussed.     

Integration of long-term fish kill data with ambient water quality monitoring data and application to water quality management

Almost half (354) of all fish kills (805) in South Carolina, USA, between 1978 and 1988 occurred in the coastal zone. These kills were analyzed for causative, spatial, and temporal associations as a distinct data set and as one integrated with ambient water quality monitoring data. Estuarine kills as a result of natural causes accounted for 42.8% followed by man-induced (35.1%) and undetermined causes (22.1%). Although general pesticide usage was responsible for 53.9% of man-induced kills, weed control activities around resorts and municipal areas accounted for slightly more kills (20.9%) than did agricultural (19.8%) or vector control (13.2%) uses. A dramatic decline in agricultural-related kills has been observed since 1986 as the integrated pest management approach was adopted by many farmers. When taken with the few kills (12.0%) resulting from wastewaters, this suggests that these two land-use activities have been successfully managed via existing programs (IPM and NPDES, respectively) to minimize their contributions to estuarine fish kills. Ambient trend monitoring data demonstrated no coastal-wide dispersion of pesticide pollution. These data confirmed the nature of fish kills to be site-specific, near-field events most closely associated with the contiguous land-use practices and intensities. Typically, fish kill data are considered as event-specific data limited to the bounds of that event only. Our analysis has shown, however, that a long-term data set, when integrated with ambient water quality data, can assist in regulatory and resource management decisions for both short- and long-term planning and protection applications.     

则木河断裂变形产物中微观粘滑与蠕滑标志的鉴别

在则木河断裂带宏观研究的基础上,结合岩石破裂实验成果,对包括1850年大震变形带在内的断裂产物进行定向原态采集、固结、制片和镜下系统观测,从复杂纷呈的变形遗迹中鉴别出微观粘滑与蠕滑标志。最后就有关问题进行了简要讨论.     

AN EXAMINATION OF THE MECHANISMS CONTROLLING GROUNDWATER GRADIENTS IN HYPER-ARID REGIONAL SEDIMENTARY BASINS1

ABSTRACT: Although evidence of modern recharge in the North African and Arabian sedimentary basin aquifers exists, it is difficult to determine the volume of recharge. Also, from the evidence of regional groundwater gradients, the flow within the aquifers seems to be appreciably greater than one would intuitively expect. A hypotehtical model embodying the characteristics of the aquifers has been used to investigate the likely significance of various possible flow mechanisms. It is shown that while dewatering in the unconfined area can possibly contribute to flows for a considerable period of time, the maintenance of water levels in the unconfined zone must be the result of modern recharge. It is also shown that recharge depths of less than 10 mm per annum are sufficient given suitable aquifer parameters. Results for various combinations of aquifer parameters and configurations are given, including layered aquifers and the effects of restricted oufflows. Comparisons are made using a “bench mark” example. The work indicates that there is little point in carrying out conventional hydrological balance studies in hyper-arid areas and that, instead, more emphasis should be placed upon good groundwater hydrographic data and modeling.     

MULTICOMPONENT GEOCHEMICAL TRANSPORT MODELING USING HYDRUS-1D AND HP11

Abstract: The transport of reactive contaminants in the subsurface is generally affected by a large number of nonlinear and often interactive physical, chemical, and biological processes. Simulating these processes requires a comprehensive reactive transport code that couples the physical processes of water flow and advective-dispersive transport with a range of biogeochemical processes. Two recently developed coupled geochemical models that are both based on the HYDRUS-1D software package for variably saturated flow and transport are summarized in this paper. One model resulted from coupling HYDRUS-1D with the UNSATCHEM module. While restricted to major ion chemistry, this program enables quantitative predictions of such problems as analyzing the effects of salinity on plant growth and the amount of water and amendments required to reclaim salt-affected soil profiles. The second model, HPI, resulted from coupling HYDRUS-1D with the PHREEQC biogeochemical code. The latter program accounts for a wide range of instantaneous or kinetic chemical and biological reactions, including complexation, cation exchange, surface complexation, precipitation dissolution and/or redox reactions. The versatility of HP1 is illustrated in this paper by means of two examples: the leaching of toxic trace elements and the transport of the explosive TNT and its degradation products.