南水北调东线调度对南四湖水质的影响

南水北调东线一期工程2013年通水,必将对南四湖水质产生重大影响.借鉴既有成功理论方法,建立南四湖三维水力调配和水质模型,并经实测值验证.利用该三维模型,模拟南水北调东线一个完整调水期中的南四湖常规、干旱调水工况调度运行过程,分析南四湖上级湖、下级湖的水力和水质变化规律,提出加强和改善南水北调东线调度管理的措施和建议,既可充分发挥南水北调工程效益,又可改善南四湖水质.     

南水北调西线工程深埋隧道地质超前预报系统研究的思考

深埋长隧道是南水北调西线工程施工中的难点,隧道地质超前地质预报可分为施工前地质预报和施工阶段地质预报,目前施工前地质预报应用的可控源音频大地电磁法及施工阶段应用的地质雷达、TSP、红外辐射测温技术有一定的效果,但是针对南水北调西线工程这样复杂的岩层,必须对现有的预报方法进行改进.     

南水北调西线千米深长隧洞围岩构造地球物理勘探

2004年对南水北调引水隧洞西线一期工程中玛柯河－贾曲段20 km深埋长隧洞进行了地质结构面、岩性特征、赋水性等地球物理勘探、工程地质勘查,并进行综合解释以查清勘探区影响引水隧洞工程建设的不良地质体和不良地质构造.本文介绍了CSAMT法隧洞勘探的特点、资料采集的过程及应特别注意的复杂地形资料处理技术,结合其他补充物探手段及地面工程地质勘察结果对20 km深埋长隧洞围岩介质的结构特征进行了解释,指出了可能影响工程的断层、破碎带及异常区     

A unified framework for earthquake risk assessment of transportation networks and gross regional product

Natural threats like earthquakes, hurricanes or tsunamis have had serious impacts on communities. In the past, major earthquakes in the United States like Loma Prieta 1989, Northridge 1994, or recent events in Italy like L’Aquila 2009 or Emilia 2012 emphasized the importance of preparedness and awareness to reduce social impacts. In addition to that, earthquake damaged businesses dramatically reduced the gross regional product. Generating scenario earthquakes in a proper way is important to suitably assess the risk in bridge networks and social losses in terms of gross regional product reduction. Seismic hazard is traditionally assessed by means of probabilistic seismic hazard analysis (PSHA). Although PSHA well represents the hazard at a specific location it is not suitable for spatially distributed systems. Scenario earthquakes can overcome this problem; they represent the actual distribution of ground shaking for a spatially distributed system while being hazard consistent. In this work a methodology to generate scenario earthquakes has been proposed using a novel approach with the aim of being the basic step for investigating possible earthquake consequences in seismic areas and contributing to reduce losses.     

Numerical studies on the influences of the South‐to‐North Water Transfer Project on groundwater level changes in the Beijing Plain,China

Groundwater is an important component of the water supply, and overexploitation has triggered many problems in the Beijing Plain. The South‐to‐North Water Transfer Project has been proposed as a promising solution to alleviate these problems. Evaluation of different scenarios of groundwater management after the implementation of the South‐to‐North Water Transfer Project is necessarily required. In this study, a numerical model of groundwater flow was established using FEFLOW software and was well calibrated by parameter optimization and groundwater withdrawal inversion in the Beijing Plain. Sixteen scenarios that considered groundwater exploitation, artificial recharge, and precipitation were designed to simulate the groundwater dynamics after 11 years of the project. The results showed that the groundwater level in the study area would recover to various degrees due to the reductions of groundwater withdrawal and the increments of infiltration; additionally, it was concluded that groundwater was significantly affected by precipitation. Generally, in the designed scenarios, the groundwater‐level increment in the upper streams of the model area was higher than that in the lower streams. The groundwater level would obviously increase from artificial recharge in the immediate and adjacent areas. In addition, modes of reducing exploitation had no significant influence on the change in groundwater level during the 11‐year study period. The developed model offers a reliable and effective way to improve groundwater management.     

南水北调中线水源地河流大型无脊椎动物物种多样性及其维持机制

生物多样性的形成与维持(即群落构建)一直是生态学研究的重要论题。有关亚热带季风区大型河流生物多样性格局及维持机制的认识仍十分有限。以汉江上游(南水北调中线水源地)为研究区域,以大型无脊椎动物为研究对象,系统开展群落多样性时空格局及其维持机制的研究。于2015—2017年间共采集到大型无脊椎动物333个分类单元,隶属6门10纲25目110科279属,包括水生昆虫278种(83.5%),环节动物门25种(7.5%),软体动物门19种(5.7%),软甲纲7种以及其它动物4种。物种多样性在时间和空间尺度上差异显著:时间上,春季物种数最多(227种),夏季(140种)、秋季(141种)和冬季(144种)较少;空间上,自然河流金水河物种数最多(179种),而金钱河(163种)、月河(149种)、淇河(140种)和泗河(112种)等人类干扰河流相对较少。db-RDA分析表明,尽管不同季节所筛选出的关键因子有所差异,但环境因子和空间因子均显著影响着大型无脊椎动物的群落结构。变差分解分析显示,环境过滤是流域内大型无脊椎动物群落多样性维持的主导因素,而空间过程(扩散限制)则起着次要的作用。本研究对南水北调...     

南水北调中线水源区浮游植物

通过对南水北调中线水源区水体浮游植物的调查,结合理化指标的逐月测定,结果表明:该水域共有浮游植物8门40属71种(包括变种),其中以硅藻门的种类占优势,浮游植物的种类和数量随季节和水域不同而呈现差异,浮游植物对水体污染具有较好的指示作用,水体为寡污型水体.本研究为建立中线水源区长期生态研究数据信息库及库区生态环境保护政策制定提供科学依据.     

不同典型年“引江济巢”工程对巢湖水质的影响

“引江济巢”作为引江济淮的起始段工程,承担着改善巢湖水质的重要任务,调水路线的选取对水质改善效果有关键影响.本文基于MIKE21模型构建了巢湖水动力水质模型,分别模拟了丰水年、平水年和枯水年情景下巢湖流场和总氮、总磷浓度时空分布特征,以及不同调水路线在各典型年对巢湖水质的影响.结果显示巢湖流场和水质分布有明显的空间差异性,受入湖负荷和流量影响,巢湖在丰水年水质较差,整体来说东湖区水质优于西湖区.相比其他年份,丰水年调水对湖区水质的改善作用最明显;不同调水路线中,自白石天河入流相较兆河入流对巢湖,尤其是西湖区水质改善明显.     

南水北调中线干渠浮游植物群落时空格局及其决定因子

为了解南水北调中线干渠浮游植物群落的时空格局,自2018年8月开始分4个季度对干渠沿程的11个样点进行采样调查,同步开展水环境调查;共检出浮游植物7门83属145种,物种丰富度上,硅藻种类数最多,绿藻和蓝藻分别占第2和第3位,且春季＞秋季＞冬季＞夏季;优势种包括极小曲丝藻(Achnanthidum minutissim...     

太湖水龄分布特征及“引江济太”工程对其的影响

太湖作为典型的风生流湖泊,风场对水体运输和交换的过程起着重要的作用.基于环境水动力学模型EFDC源程序建立了染色剂模型以及水龄模型,借助水龄研究太湖水体的长期输运过程和更新速率特征,从而为太湖的调水工程管理提供科学依据.本文在研究春、夏、秋、冬季不同风场作用下太湖的水龄季节性分布特征的基础上,结合太湖实测风速、流量数据及"引江济太"工程调水运行的现状,着重分析了望虞河枢纽调水运行以及新沟河工程对太湖水龄分布的影响.数值试验的模拟结果表明:太湖水体交换受季风影响明显,春、夏季的水龄相对较大、水体交换较差;靠近湖流入口处的地方水龄较小,远离入口的地方水龄较大;水流流向与风向一致时水龄减小,水循环加快,反之则减慢.望虞河引水引工程能够减小贡湖及湖心区的水龄,加快贡湖湖区及湖心区的水循环;新沟河工程引水能够减小梅梁湖区的水龄,改善该湖区的水质.引水工程的实施对加快整个太湖的水循环做出重要贡献.     

南水北调东线工程运行3年后东平湖浮游植物群落特征及环境驱动因子

为掌握东平湖浮游植物在南水北调东线工程运行后的群落结构变化特征及探究其环境驱动因子,于通水运行3周年后的2017年分4个季节对东平湖的18个样点进行采样调查,同步开展水环境调查.结果 显示:共检出浮游植物191种属(包括变种),其中硅藻门、绿藻门、裸藻门、蓝藻门、金藻门、黄藻门、甲藻门和隐藻门分别为64、57、28、2...     

Ecological risk assessment of eutrophication in Songhua Lake, China

The Songhua Lake in the Northeast China is chosen as a study case in this paper. Monitoring of samples and analysis 18 indexes related to the eutrophication in the Songhua Lake had been conducted in 2002–2004. Ecological risk assessment methods are employed here. The study results showed that total phosphorus and total nitrogen were main risk factors to impact on the eutrophication of the Songhua Lake, and influence of the phosphorus on the lake eutrophication was larger than that of nitrogen. Algal growth potential test was also conducted to validate the results. High phosphorus and high nitrogen concentrations were mostly distributed in Huifahekou and Jiaohe sites of the Songhua Lake. Threshold values of total phosphorus, total nitrogen and Chl-a concentrations from dose-effective examination were 0.065 mg/L, 0.843 mg/L, and 11.90 μg/L, respectively. The probability of the eutrophication appeared in the Songhua Lake was 0.69, of them, risk-free type area was 19.21% of total lake area, slight risk type area was 30.10%, middle risk type area was 16.50%, heavy risk type area was 25.8%, hyper risk type area was 8.39%. In order to control the eutrophication in the Songhua Lake, maximum permission discharges of total phosphorus and total nitrogen to the lake would be 2,123.78, 7,018.82 t/a, respectively.     

基于南水北调西线工程岩性特征的CSAMT法有限元三维数值模拟研究

有限元法是地球物理数值模拟中常用的方法,本文采用三维可控源音频大地电磁法(CSAMT)有限元数值模拟的程序,根据南水北调西线工程岩性的地球物理特征,设置了不同的三维模型,并对其进行了有限元数值计算分析,从三维空间中模拟场的规律,探索了不同地质异常体的特征,为提高可控源音频大地电磁法在南水北调西线工程深埋藏隧洞探测地质异常体的精度奠定了基础.     

The impact of the South–North Water Transfer Project (CTP)'s central route on groundwater table in the Hai River basin,North China

The central route of the South–North Water Transfer Project (CTP) is designed to divert approximately 9.5 billion m³ of water per year from the Han River, a major tributary of the Yangtze River, to the Hai River basin in the north China. The main purpose of this study is to assess the impact of CTP on groundwater table in the Hai River basin. Our study features a large‐scale distributed hydrological model that couples a physically based groundwater module, which is sub‐basin‐based, with a conceptual surface water module, which is grid‐based. There are several grids in each sub‐basin and water exchange among grid that are considered. Our model couples surface water module and groundwater module and calculates human water use at the same time. The simulation results indicate that even with the water supply by CTP, the groundwater table will continue to decline in the Hai River basin. However, the CTP water can evidently reduce the decline rate, helping alleviate groundwater overexploitation in Hai River region. Copyright © 2013 John Wiley & Sons, Ltd.     

Identification and assessment of water safety risk for groundwater recharge with reclaimed water in China

Groundwater recharge using reclaimed water has developed rapidly around the world to relieve the groundwater resource shortage and declining of the water table. Traditional water treatment systems are inefficient to remove all the types of contaminants, so it is urgent to identify the priority chemical substances (CSs) that deserve our first concern. In this study, we developed a method (EER method) to identify priority CSs in groundwater recharge by surface spreading and direct aquifer injection. Three stages were processed which were exposure assessment, effect assessment and ranking for identification of priority CSs. Fourteen cities in China were selected for data collected and 90 pollutants in reclaimed water samples were analyzed as the target pollutants for a case study. According to three stages, the 90 CSs studied were divided into five groups (primary control CSs and high, moderate and low and no risk control CSs). In the primary control CSs and high, moderate and low and no risk control CSs group there were 14, 18, 21, 21 and 16 CSs, respectively when groundwater recharged by surface spreading, while there were 15, 18, 21, 21 and 15 CSs when recharged by direct injection. This method provided an indicator of prioritizing the risk of 90 compounds in the reclaimed water for groundwater recharge.     

Strategic assessment of fuel taxation in energy conservation and CO2 reduction for road transportation: a case study from China

Road transportation has attracted extensive attention throughout the world because of its high energy demands and numerous externalities. Sustainable road transportation has thus become a great challenge for politicians and decision-makers all over the world. There have been a series of studies indicating that appropriate pricing of fuel can be both effective and efficient for reducing overconsumption of transport fuel. However, relatively little research has been done on fuel price approaches in developing country contexts. For a country like China, where road traffic today is growing more than in other countries, there is a strategic interest to do more economic analyses of fair and efficient pricing of fuel. In this study, we present a strategic assessment of fuel pricing in energy conservation and CO₂ reduction from road transportation in China, both in a retrospective and a prospective perspective. First of all, the correlation between fuel price and road transport gasoline demand, based upon data from 1995 to 2007, was examined with an econometric model. Secondly, on basis of the elasticity model, the potential reductions with respect to fuel demand and Green House Gas (GHG) emissions as a consequence of a strategic fuel tax implementation in China were examined up to 2030. The results indicate that such strategic fuel taxation can play a considerable role in steering the growth of road transport gasoline demand, and thus also Chinese GHG emissions.     

Screening level ecological risk assessment for synthetic musks in surface water of Lake Taihu, China

A total of thirty-three surface water samples were collected from Meiliang Bay, Gonghu Bay and Xukou Bay of Lake Taihu, and analyzed for synthetic musks, including 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-[γ]-2-benzopyrane (HHCB), 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN), 1-tert-butyl-3,5-dimethyl-2,5-dinitro-4-acetylbenzene (MK) and 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene (MX). Ecological risks of these compounds were characterized by hazard quotient (HQ) method due to a lack of sufficient available toxicity data of synthetic musks. HHCB was the main synthetic musk detected in Lake Taihu, followed by AHTN, MK, and MX. The risk assessment results indicate that low ecological risks were posed by HHCB and total synthetic musks, and even lower risks posed by other synthetic musks in the worst case; much lower ecological risks were caused by both individual and total synthetic musks in the general case. The combined ecological risk from total synthetic musks calculation suggests that the combined ecological risk from all four synthetic musks was expected to be slightly higher than for the individual musks due to their joint action. The HQ spatial distribution maps show that several hot-spot areas were mainly around the river inlets to Lake Taihu, indicating that synthetic musks may be transported to Lake Taihu with municipal sewage and industrial wastewater from surrounding areas. However, the ecological risks in hot-spot areas posed by individual and total synthetic musks were still acceptable.     

构建和谐社会中的巨灾风险防范 --我国地震巨灾风险证券化的实证分析

党的十六大首次提出了“和谐社会”的概念,而人与自然的和谐成为这一概念的重要内涵之一.我国作为世界上自然灾害最严重的国家之一,亟需构筑符合我国国情的巨灾风险防范体系.保险风险证券化作为国际保险市场化解巨灾风险的一项重要创新,也正在为我国保险业所关注.为此本文选取了在我国发生频率最高、造成损失最大的自然灾害-地震灾害作为研究对象,对我国地震巨灾债券的构建与定价进行了实证分析,即利用实际的样本数据和有关非寿险精算的有关原理,构建了我国的地震巨灾债券,并同时完成了价格体系的制定.以上研究可以为巨灾风险证券化在我国的推广提供可资参考的方法与依据.     

Capturing the time-dependence in the precipitation process for weather risk assessment

This work investigates the seasonal, long-term and time-dependence properties of the precipitation process using daily precipitation amount records in Calgary and develops occurrence–amount models which capture the complex properties of the process. Data show that: (a) the probability of precipitation occurrence not only depends on the occurrence of the previous days, but also depends on the amount values. Moreover this dependence varies with season. (b) The expected amount and its volatility depend on the occurrence as well as the amount on the previous days—these dependencies reveal seasonal patterns. (c) There is a strong long-term dependence in Calgary’s data. The proposed models in this work satisfy these properties. A large set of covariates is built to capture the complexity of various properties of the precipitation process. A grouped sequential model selection approach is used to pick the appropriate covariates which works by assigning the predictors to various groups and sequentially exploring them. This framework is assessed by comparing the simulations from the models to the observed data. This confirms a satisfactory agreement.     

Seismic assessment of masonry buildings accounting for limited knowledge on materials by Bayesian updating

Several building codes propose methodologies to account for epistemic uncertainties in the seismic assessment of masonry buildings by selecting a knowledge level and reducing material strengths by means of the associated value of the confidence factor. Previous works showed that, in the case of masonry structures, this approach has various limitations, such as the lack of proper consideration of experimental tests performed. This article focuses on the issue of imperfect knowledge on material properties of existing masonry buildings and proposes a probabilistic methodology for the assessment, based on Bayesian updating of mechanical properties. The use of a Bayesian approach allows to update the values of the material properties assumed a priori as knowledge on the building increases, by taking into account all the experimental information gathered during the assessment process. A large number of simulated assessments is carried out and the values of the confidence factors on material properties are defined through the comparison between the obtained results and those of the reference structure, assumed to be perfectly known. These factors are useful in a more general framework for the assessment of masonry buildings accounting for different sources of uncertainty.