Parameter uncertainty analysis of non-point source pollution from different land use types

Land use type is one of the most important factors that affect the uncertainty in non-point source (NPS) pollution simulation. In this study, seventeen sensitive parameters were screened from the Soil and Water Assessment Tool (SWAT) model for parameter uncertainty analysis for different land use types in the Daning River Watershed of the Three Gorges Reservoir area, China. First-Order Error Analysis (FOEA) method was adopted to analyze the effect of parameter uncertainty on model outputs under three types of land use, namely, plantation, forest and grassland. The model outputs selected in this study consisted of runoff, sediment yield, organic nitrogen (N), and total phosphorus (TP). The results indicated that the uncertainty conferred by the parameters differed among the three land use types. In forest and grassland, the parameter uncertainty in NPS pollution was primarily associated with runoff processes, but in plantation, the main uncertain parameters were related to runoff process and soil properties. Taken together, the study suggested that adjusting the structure of land use and controlling fertilizer use are helpful methods to control the NPS pollution in the Daning River Watershed.     

长江三峡库区野果植物资源区系特征分析

根据"长江三峡库区野果植物资源数据库",采用植物区系分析方法,对长江三峡库区野果植物资源区系特征进行了系统分析和研究,得出以下结论:库区野果植物资源在库区植被中占据相当的优势;长江三峡库区野果植物中主要成分为含10种以上的大科和大属;分布区类型分析表明库区野果植物与热带植物区系和北温带植物区系有一定的联系:拥有丰富的特有科属植物种类.     

山地城镇生态环境敏感因素探析——以三峡库区为例

本文根据三峡库区的实地调研与历史文献资料分析,从山地生态系统的特征入手,解读造成库区城镇生态环境敏感的主要因素及其对城镇建设的影响,归纳总结库区城镇在建设过程中对各类生态环境敏感区的建设性利用措施,以期对引导福建省山地城镇生态环境敏感区的合理保护与规划建设,维护山地城镇的生态化与可持续发展具有启示及借鉴意义。     

Numerical simulation of oil spill for the Three Gorges Reservoir in China

The water body is just like a quasi‐static fluid after the impoundment of the Three Gorges Reservoir in China to 175 m water level in late 2010. In this paper, fluid dynamic model and numerical method were presented to analyse its dynamic characteristic. Then, based on an oil spill model coupled with the hydrodynamic model, the oil fractions evolvement with time as well as the recovery process with emergency actions under oil spills were numerically simulated and illustrated in the Three Gorges Reservoir. Emergency actions were accordingly analysed based on the simulated pollution area and density, by which a decay parameter was additionally brought into the simulation to understand the recovery of polluted area. The simulated results could be an aid for better emergency response strategy in case of oil spill accidents in the Three Gorges Reservoir in China.     

三峡库区万州第三水厂虹吸滤池的改造

万州第三水厂原虹吸滤池采用孔眼滤板小阻力配水系统,由于配水不均,造成过滤和反冲洗效果差,滤料流失严重,出水浊度出现超标现象,为此对原虹吸滤池配水系统进行了改造.取消原有的孔眼滤板和尼龙网,改用ABS工程塑料短柄滤头加滤板的配水系统,对承托层、滤料层进行调整.两年的运行结果表明,改造后的虹吸滤池过滤和反冲洗效果明显改善,出水水质优于国家饮用水卫生标准.     

三峡库区岩质边坡稳定性分析与防治工程设计

基于极限平衡理论,针对三峡库区岩质边坡,分析了边坡的结构构造、破坏模式以及稳定性计算方法,并对该段边坡进行了稳定性计算。研究结果表明,该边坡为顺向坡,坡面与岩层面基本吻合,有可能沿岩层面发生顺层滑移,该高切坡的稳定性较低。通过对边坡采用锚杆加固、挂网喷射混凝土护坡的治理措施,可以增强边坡的整体稳定性。     

实时自动监测系统在库区某滑坡监测中的应用

三峡库区首次175 m试验性蓄水过程中,三峡库区云阳县某滑坡出现了险情,受到地质勘测相关部门及社会各界的广泛关注。为了实时掌握该滑坡的变形动向,通过无线网络并结合Internet网络,利用无线远程数据传输系统,实现对数据的采集和无线传输,并通过信息处理中心建立起完整的监测系统,以实现对该滑坡的实时自动监测。一年来的运行结果显示,实时监测系统保证了监测数据的连续性,可以较好的反映出滑坡的变形特征及变形趋势,且该系统具有低功耗、低成本、高可靠性等特点,是一套比较理想的监测系统。     

三峡库区城镇土地利用结构优化探析

三峡库区正处于快速城镇化的关键时期,城镇规模急剧膨胀,城镇建设占用大量土地,土地资源短缺与人们生存需要的矛盾日益突出,这已严重影响到库区城镇的经济、社会、生态环境的可持续发展目标的实现。针对三库区城镇化进程中出现的土地利用问题,提出了优化土地利用结构,走内涵集约型土地利用的途径,以期协调城镇建设与土地资源保护的关系,并进一步分析了优化土地利用结构的动力机制及对策措施。     

三峡库区农村环境连片整治工程设计实例

针对三峡库区农村环境治理设施严重缺乏的现状,结合全国农村环境连片整治技术需求,提出了与经济欠发达地区农村生活生产相适应的农村环境连片综合整治经济适用技术与总体方案:生活污水根据村落规模选用不同形式的人工湿地处理工艺,畜禽养殖废水采用沼气池发酵后还田的处理方式,生活垃圾采用户分类、村收集、镇转运、县市处理的处理模式。     

城市非点源污染研究进展及防治措施

在点源污染已得到初步控制的基础上,城市非点源污染如今已成为城市水环境的重大污染源之一并引起全球的广泛关注。对国内外学者有关城市非点源污染的来源、特征、影响因素及防治措施等方面的研究进展进行了归纳分析,并结合我国现状提出了强化非点源污染控制的几点建议。     

三峡库区网箱养鱼对周围水质的影响

以朱衣河二道河湾回水区网箱养鱼水质的现场监测结果为基础,采用综合营养状态指数法对网箱养鱼水域的现状进行了营养状态评价,并用污染物浓度等值线法进行了网箱养鱼对周围水质的影响分析.结果表明:网箱养鱼及其影响区的水体综合营养状态均为轻度富营养,水质污染程度为轻度污染,其综合营养状态变化总趋势为网箱养鱼区大于网箱影响区;网箱养鱼影响区的Chla浓度明显高于网箱核心区,其余污染物浓度的平面分布总趋势是由网箱核心区向网箱影响区由高向低变化;若以超河流背景断面浓度5%作为划定超背景污染带的标准,则朱衣河二道河湾网箱养鱼引起CODMnNH3-N、TN、TP和Chla超背景的污染面积分别为35 000、22 500、23 760、54 000和16 000 m3,分别是网箱养鱼区面积(3 900 m2)的9、5.8、6.1、13.8和4.1倍.     

三峡库区重庆涪陵第二水厂扩建工程设计

重庆市涪陵第二水厂扩建工程(原规模为6×104m3/d,新增规模为4×104m3/d),包括新建取水泵站、净水处理构筑物和输水管道等几部分。针对长江原水浊度较高的特点,采用了两级高效反应沉淀池、均质石英砂滤料气水反冲洗滤池处理工艺。两年多的运行实践表明,该工程不仅达到并优于原设计要求,而且投资省、运行费用低、占地少,为其他类似老水厂的扩建提供了新思路。     

三峡库区某高切坡稳定性分析与治理措施

对三峡库区某高切坡的稳定性进行定量分析计算,并对该高切坡的加固与防护措施进行了施工图设计。首先,根据高切坡的特点将其分为3个区段,分析了高切坡变形的地质条件和边坡滑移模式,针对不同的滑移破坏类型提出相应的稳定性计算方法。然后,对该高切坡多个典型地质剖面,在天然状态和暴雨工况下分别进行稳定性计算,得到其安全系数为0.939～1.268,表明该高切坡在暴雨工况下的稳定性较低。最后,在定量评价边坡稳定性的基础上,对高切坡的3个区段,分别采取清除危岩体、锚杆加固、挡土墙固脚与挂网喷射混凝土护坡等综合治理措施,以增强边坡的整体稳定性。实践证明,这些措施可以消除高切坡滑移的安全隐患,工程治理效果良好。     

长江三峡库区支线航空运输发展对策研究

长江三峡库区丰富的自然与人文旅游资源,狭长的地形与复杂的山地环境特征,决定了支线航空有广阔的前景。支线航空运输具有建设投资省、方便快捷、服务半径大等优点,是三峡库区发展旅游的重要基础条件。分析了长江三峡库区航空运输的现状及存在问题,结合区域城镇体系建设及综合交通发展,提出了支线航空交通的前景与发展对策。     

三峡库区典型山地城市排水管道结构性安全分析

针对三峡库区典型山地城市重庆主城排水截流干管周边地质状况、管道结构形式、支撑情况、荷载工况等,分析了山地城市排水管道的结构性安全状况,确定了截流干管的不利管段,并对其进行了强降雨、滑坡等不利荷载工况下的承载力安全分析,针对重庆主城排水干管A线工程安全运行提出了在线监测建议.     

三峡场镇与码头

近年来,处于开拓生存空间、获取生存资源以及回归自然的需要,人们越来越重视对山地的研究,山地建筑创作活动也随之显得重要。重庆地处西南山地,是个典型的具有山地特征的城市,长期以来,形成了特有的山地城市地理特点与文化特征,并具有代表性。本栏目刊出的两篇文章,向我们很好地阐释了山地滨水城市的建筑设计理念及文化特征。     

Reservoir-induced landslides and risk control in Three Gorges Project on Yangtze River,China

The Three Gorges region in China was basically a geohazard-prone area prior to construction of the Three Gorges Reservoir(TGR).After construction of the TGR,the water level was raised from 70 m to 175 m above sea level(ASL).and annual reservoir regulation has caused a 30-m water level difference after impoundment of the TGR since September 2008.This paper first presents the spatiotemporal distribution of landslides in six periods of 175 m ASL trial impoundments from 2008 to 2014.The results show that the number of landslides sharply decreased from 273 at the initial stage to less than ten at the second stage of impoundment.Based on this,the reservoir-induced landslides in the TGR region can be roughly classified into five failure patterns,i.e.accumulation landslide,dip-slope landslide,reversed bedding landslide,rockfall,and karst breccia landslide.The accumulation landslides and dip-slope landslides account for more than 90%.Taking the Shuping accumulation landslide(a sliding mass volume of 20.7 × 10~6 m~3) in Zigui County and the Outang dip-slope landslide(a sliding mass volume of about 90 × 10~6 m~3) in Fengjie County as two typical cases,the mechanisms of reactivation of the two landslides are analyzed.The monitoring data and factor of safety(FOS) calculation show that the accumulation landslide is dominated by water level variation in the reservoir as most part of the mass body is under 175 m ASL,and the dip-slope landslide is controlled by the coupling effect of reservoir water level variation and precipitation as an extensive recharge area of rainfall from the rear and the front mass is below 175 m ASL.The characteristics of landslide-induced impulsive wave hazards after and before reservoir impoundment are studied,and the probability of occurrence of a landslide-induced impulsive wave hazard has increased in the reservoir region.Simulation results of the Ganjingzi landslide in Wushan County indicate the strong relationship between landslide-induced surge and water variation with high potential risk to shipping and residential areas.Regarding reservoir regulation in TGR when using a single index,i.e.1-d water level variation,water resources are not well utilized,and there is also potential risk of disasters since 2008.In addition,various indices such as 1-d.5-d,and 10-d water level variations are proposed for reservoir regulation.Finally,taking reservoir-induced landslides in June2015 for example,the feasibility of the optimizing indices of water level variations is verified.     

三峡库区某高切坡稳定性分析及治理

对位于巫山县的一处高切坡进行分析,探讨了影响高切坡稳定性的各项因素,采用极限平衡法及工程地质类比法等分析方法对其稳定性进行了计算分析和预测评价,并提出了预应力锚索+肋柱锚杆面板+浆砌石护坡挡土墙+截排水设施的工程治理方案。     

城市住宅小区非点源污染及其防治研究

概述了住宅小区非点源污染的定义、特点及其原因,针对小区非点源污染的危害,对小区非点源污染的防治方法进行了详细探讨,并介绍了国内外雨水利用的现状,以期为我国城市小区非点源污染控制和决策提供参考和借鉴.