地下水资源可持续性评价的指标及其标准

有效的保护、管理、可持续利用地下水是水资源研究的核心目标之一,地下水可持续性评价是实现该目标的前提.现从环境、经济、社会3个方面探讨了地下水可持续性评价指标体系的建立思路,设计了11个评价指标,介绍了相应指标的计算方法和标准,不同地区可选择不同的指标集合做差异性评价.这些评价指标涵盖了当前地下水资源面临的主要制约因素,反映了人类活动对地下水的影响,对区域地下水资源可持续性评价有实际的借鉴意义.     

土石路基压实度可靠性分析与评价

压实度是衡量路基填筑质量的一个重要指标,长期工程实践中形成了灌砂法、波动法等多种检测手段。然而,它们的点测性或面测性严重影响了路基压实度评价的可靠性和代表性。为此,基于土石路基变异性分析,将工程实际中的压实度与可靠性理论相结合,建立路基压实度与可靠性理论相耦合的二元评价体系,从而实现路基填筑质量评价的有效性和可靠性。     

Indicators and a Neuro-Fuzzy Based Model for the Evaluation of Water Supply Sustainability

In the field of water management, the evaluation of sustainability has no universal methodological approach nor any consensus regarding the definitions of sustainability or sustainable development. There is an essential need therefore for a precise definition of sustainability in different water management fields. This paper deals with the sustainability of one part of urban water management, namely a water supply. A precise definition of a sustainable water supply system is given, together with a methodological framework that quantifies the degree of water supply sustainability. The proposed framework relies on the proposed quasi-strong sustainability concept, its components (dimensions), their particular relationships and corresponding indicators representing individual processes in the water supply system and utility. The processing of indicators is performed through a joint fuzzy logic/neural network (ANFIS) model. In order to evaluate each sustainability component, separate ANFIS models were created whose results were aggregated into a single result (sustainability index). According to the presented framework, sustainability is evaluated for 17 public water supply systems/utilities in Croatia.     

渭河健康生命的主要标志及评价指标体系研究

渭河现状生命存在的主要问题是：①河流水沙循环通道不畅,河床失稳;②枯水期水量严重不足,河道水流连续性受到威胁;③水环境质量达不到水域功能要求;④河流生态结构受损;⑤洪水风险和洪涝灾害问题突出。通过探讨渭河健康生命的基本内涵和主要标志,建立了渭河健康生命评价指标体系,包括：稳定河床维持指标、水域功能实现指标、良好生态维系指标、人水和谐指标等。提出维护渭河健康生命的主要措施是：①完善防洪减灾工程体系;②构建洪水管理体系;⑧完善河道监测评价及劣变心对体系;④构建水环境监测及污染控制体系;⑤构建渭河旅游娱乐生态景观体系;⑥组建一支河流综合管理队伍等。     

Harmonisation of Reliability Performance Indices for Planning and Operational Evaluation of Water Supply Reservoirs

The planning and operational performance evaluation of water supply reservoirs routinely use the volume-based (R_v) and time-based (R_t) reliability indices but decision making is often complicated by trade-off necessitated by the fact that the two are never the same, with R_v ≥ R_t. This study has resolved the problem by harmonising the two indices. Using data from ten global rivers, simulations of hypothetical reservoirs were carried out to determine capacity for specified demands and R_t values. The corresponding R_v values were then evaluated and the resulting reliability biases (i.e. R_v – R_t) were found. To harmonise the two indices, i.e. to nullify the biases, the concept of water shortage threshold was introduced, which is the minimum quantity of water shortage that can be taken as constituting real failure for the purpose of R_t evaluation; shortage quantities below this will be disregarded. The results showed that the water shortage threshold that nullifies the reliability bias can be as high as 60% of the demand, depending on the runoff variability, the demand and the specified R_t. When averaged over all the situations analysed, the water shortage threshold was found to be 51% of the demand. Although this might appear high, it is argued that it is plausible both within the context of developed economies, where unaccounted-for-water can be much higher than 51%, and of underdeveloped economies where large sections of the population have no access to adequate water supply. In the latter case, a reduction of 50% in water supplied that guarantees uninterrupted supply of the other 50% will be deemed satisfactory and reliable, while for the former, a shortage of 50% that forces a change in behaviour to waste less water will also be deemed satisfactory. The significance and novelty of this study stem from the fact that it has removed the need for the trade-off between the two reliability indices, thus enabling unequivocal characterisation of water supply reservoir performance for effective decision making.     

山洪易发区土石坝安全评价模型的建立

基于对山洪易发区洪水致灾机理的分析,在对山洪灾害基本特点进行探讨的基础上,分析了山洪易发区洪水的致灾机理,进而提出了山洪易发区土石坝安全的影响因素和安全评价模型建立的原则.然后采用数学理论建立了由9个一级指标、20个二级指标构成的安全评价模型.     

水电站碳减排评价中功率密度指标的若干改进建议

鉴于水库温室气体排放的不确定性,联合国清洁发展机制(CDM)执行理事会(EB)在其批准的可再生能源发电并网项目整合的基准线方法学(ACM0002)中,提出了一种以功率密度为判定依据,用来核证带水库水电站的CDM项目合格性的指标。该指标以装机发电容量除以水库满库容时的淹没表面积来表征。经分析,用装机容量表征发电减排量存在一定的缺陷,用水库满库容时淹没表面积表征水库温室气体排放量也不尽合理。为此,本文根据水电的特点进行了修正和改进,建立了减排效率指标以及相应的评价标准。     

Evaluation of Three Numerical Weather Prediction Models for Short and Medium Range Agrohydrological Applications

The skill and accuracy of the quantitative precipitation forecasts by CCAM, UM and NCEP-MRF models are verified using various statistical scores at the Mgeni catchment in KwaZulu-Natal, South Africa. The CCAM model is capable of identifying a rainfall event, but with a tendency of under-estimating its magnitude. The UM model is capable of distinguishing rainy days from non-rainy days, but with a significant over-estimation of rainfall amount. There is no significant difference between the 1 and 2 day lead time UM forecasts. Statistical comparisons show that there is an acceptable skill in the CCAM forecasts, but the forecast skill of the UM model is low and unreliable. The role of the initial hydrological conditions in affecting the accuracy of CCAM and UM streamflows forecasts was significant. The results show that the under-estimation of the CCAM forecasts was reduced from −44% to −10%, while the over-estimation in the UM forecasts was reduced from 291% to only 59% when the ACRU agrohydrological model was initialised with observed rainfalls up to the previous day at each forecast run within the study period. The combined use of the CCAM and UM models by a “weighted averaging” had little effect in improving the skill as it is overshadowed more by the over-estimation of the UM forecasts than the under-estimation of the CCAM forecasts. Results obtained for a continuous period of 92 days showed that the NCEP-MRF rainfall forecasts were significantly over-predicted. The NCEP-MRF rainfall forecast is found to be totally unskillful, although the skill was seen to slightly increase with decreasing lead time.     

Evaluation of AMC-Dependent SCS-CN-Based Models Using Watershed Characteristics

This paper presents a quantitative evaluation of the existing Soil Conservation Service Curve Number (SCS-CN) model, its variants, and the modified Mishra and Singh (MS) models for their suitability to particular land use, soil type and combination thereof using a large set of rainfall-runoff data from small to large watersheds of the U.S.A. The analysis reveals that the existing SCS-CN model is more suitable for high runoff producing agricultural watersheds than to watersheds showing pasture/range land use and sandy soils. On the other hand, the two different versions of the Mishra-Singh model are more suitable for both high and low runoff producing watersheds, but with mixed land use.     

Comparative Evaluation of Genetic Programming and Neural Network as Potential Surrogate Models for Coastal Aquifer Management

Determining the optimal rates of groundwater extraction for the sustainable use of coastal aquifers is a complex water resources management problem. It necessitates the application of a 3D simulation model for coupled flow and transport simulation together with an optimization algorithm in a linked simulation-optimization framework. The use of numerical models for aquifer simulation within optimization models is constrained by the huge computational burden involved. Approximation surrogates are widely used to replace the numerical simulation model, the widely used surrogate model being Artificial Neural Networks (ANN). This study evaluates genetic programming (GP) as a potential surrogate modeling tool and compares the advantages and disadvantages with the neural network based surrogate modeling approach. Two linked simulation optimization models based on ANN and GP surrogate models are developed to determine the optimal groundwater extraction rates for an illustrative coastal aquifer. The surrogate models are linked to a genetic algorithm for optimization. The optimal solutions obtained using the two approaches are compared and the advantages of GP over the ANN surrogates evaluated.     

基于可靠度理论的岩质边坡经济风险评价

基于可靠度理念,提出了岩质边坡经济风险分析的基本流程和方法。以某工程料场开挖边坡为例,利用刚体极限平衡法进行了典型断面的稳定性计算,论证了边坡支护实施的必要性;基于FLAC3D数值计算软件,利用强度折减法拟定了所需支护的最危险滑动通道;通过体系可靠度计算方法对比了不同支护方案的失效概率;基于风险损失最小的原则,确定了该岩质边坡较为合理的支护方案。     

基于改进模糊综合评判的水闸安全性评价

目前,进行水闸安全性评价多采用主观性较强的基于专家经验的实用鉴定法。依据相关规范,构建了水闸安全评价指标体系,引入基于模糊模式识别模型的模糊综合评判方法,并对黄河三盛公水利枢纽工程的拦河闸进行了安全等级评价。结果与实际的专家经验法评价结论一致。     

土壤侵蚀模型在黄土高原的应用述评

土壤侵蚀模型是认识和评估水土流失过程及其环境影响的有效工具,目前已有的众多土壤侵蚀模型中,因黄土高原地形和地貌的独特性而使模型的应用受到限制。通过系统整理公开发表的文献,对在黄土高原经过验证的、涵盖不同尺度和过程表达的12个土壤侵蚀模型进行比较分析,依据模型预测精度、过程描述、应用方便程度和情景模拟能力等指标对每个模型进行评估。结果表明:模拟预测精度不随模型复杂程度的提高而提高;经验统计模型有利于土壤流失量的快速评估,物理成因模型尤其是分布式物理成因模型更适用于侵蚀过程和输沙过程的精细评估。指出未来黄土高原土壤侵蚀模型发展应着重于提升数据质量、加强模型开发与模型评估3个方面。     

溃坝后果综合评价模型特性分析及适用性研究

溃坝后果评价是计算大坝风险的核心内容之一,溃坝损失后果评估是否准确直接关系到大坝风险度的大小。溃坝后果评价是一件复杂繁琐且系统性工作,需要将生命损失、经济损失、环境影响和社会影响等4个方面的评估结果进行综合。随着数学理论发展,线性加权综合评价、模糊数学综合评价、物元综合评价、灰色关联度综合评价、主成分分析综合评价等成为常见综合评价模型。而每种模型方法各有特点,实际适用性效果各异。就常见的5种综合评价模型,以江西省5座水库溃坝后果评价为例,对5种评价模型计算特性和结果进行了比较分析,获得了每种方法使用技术要点,并得出在对多座水库的溃坝后果严重程度评估排序时,线性加权综合评价模型应用效果最为可靠,其次推荐采用物元综合评价模型的结论。     

Indicators and standards of quality for paddling on Lake Champlain

Lake Champlain is host to a diversity of recreational and other uses that may have social and ecological impacts. Questions of how much and what type of use should be allowed in recreation areas can be addressed through carrying capacity frameworks, using indicators and standards of quality. This study focuses on indicators and standards of quality for paddling on the lake along a non-motorized kayak and canoe trail. A number of indicator variables are identified, including scenery, quiet and solitude, being on the water, presence of wildlife, motorized watercraft, shoreline development, and invasive lake vegetation.Standards are formulated for three variables: 1) presence of sailboats and motorboats, 2) shoreline development, and 3) campsite impacts. Study findings indicate that conditions typically experienced by paddlers are nearing the minimum acceptable condition for both the number of motorboats and sailboats on the lake and the amount of shoreline development. Monitoring and management may be needed to maintain high quality paddling experiences on the lake.     

Polak-He算法在重力坝可靠度评估中的应用

现有的重力坝的可靠度计算方法,如一次二阶矩法、JC法等,存在误差较大或计算效率较低等缺点。基于此,将一种新的验算点搜索方法,即Polak-He算法,引入重力坝的可靠度计算中。以南水北调工程丹江口水库混凝土坝作为分析算例,为计算简便,考虑了坝体抗滑稳定和下游坝趾抗压两种失效模式,分析了影响该算法收敛的主要因素,并为这些因素的处理提出了合理建议。最后,通过算例分析了Polak-He算法的稳健性。计算表明,Polak-He法具有收敛快、精度高、稳定性好的优点。     

某高面板坝光纤陀螺仪监测成果可信度评判

某高面板堆石坝面板挠度采用光纤陀螺仪进行监测,在坝体内部也埋设光纤陀螺仪配合水管式沉降仪进行辅助坝体沉降监测。通过光纤陀螺仪数据处理、同类工程类比及与大坝其他监测仪器进行对比分析,对光纤陀螺仪数据可信度进行综合评判,得出以下结论:光纤陀螺仪获取的面板挠度量值上大于其他同类工程,大于经验公式,也大于邻近面板垫层料内水管式沉降仪和引张线水平位移计矢量计算得到的成果;光纤陀螺仪获取的2015年的沉降速率大于同时段同位置的水管式沉降仪、坝顶表面变形的沉降速率,不符合一般规律。因此,该工程的光纤陀螺仪测值可信度不高。     

Definition of Risk Indicators for Reservoirs Management Optimization

An alternative procedure for drought risk assessment and for the mitigation of drought risk is proposed in the paper. An analysis of the relationship between failure of water supply systems and reservoir volumes for the urban area of Firenze in central Tuscany, in central Italy, is performed. Long term simulations are carried out using the software package WEAP. A simplified model of the water resources system is built to assess the threshold values and the management rules. The probability to have definite degree of shortage in the water supply system is evaluated in function of the volume stored in the reservoir at the beginning of the month with Monte Carlo simulations. The reservoir levels and volumes are simulated using time series of the period 1970–2005. Four scenarios (i.e. normal, pre-alert, alert and emergency) associated with different levels of severity of drought are defined. Threshold values are identified considering the probability to assure a given fraction of the demand in a certain time horizon, and are calibrated with an optimization method, which try to minimize the water shortages, especially the heavier. The critical situations are assessed month by month in order to evaluate optimal management rules during the year and avoid conditions of total water shortage.     

Evaluation of Crop Models for Simulating and Optimizing Deficit Irrigation Systems in Arid and Semi-arid Countries Under Climate Variability

The variability of fresh water availability in arid and semi-arid countries poses a serious challenge to farmers to cope with when depending on irrigation for crop growing. This has shifted the focus onto improving irrigation management and water productivity (WP) through controlled deficit irrigation (DI). DI can be conceived as a strategy to deal with these challenges but more knowledge on risks and chances of this strategy is urgently needed. The availability of simulation models that can reliably predict crop yield under the influence of soil, atmosphere, irrigation, and agricultural management practices is a prerequisite for deriving reliable and effective deficit irrigation strategies. In this context, this article discusses the performance of the crop models CropWat, PILOTE, Daisy, and APSIM when being part of a stochastic simulation-based approach to improve WP by focusing primarily on the impact of climate variability. The stochastic framework consists of: (i) a weather generator for simulating regional impacts of climate variability; (ii) a tailor-made evolutionary optimization algorithm for optimal irrigation scheduling with limited water supply; and (iii) the above mentioned models for simulating water transport and crop growth in a sound manner. The results present stochastic crop water production functions (SCWPFs) that can be used as basic tools for assessing the impact on the risk for the potential yield due to water stress and climate variability. Example simulations from India, Malawi, France and Oman are presented and the suitability of these crop models to be employed in a framework for optimizing WP is evaluated.