Improving Expert Panel Assessments through the use of a Composite River Condition Index—the case of the rivers affected by the Snowy Mountains hydro‐electric scheme,Australia

A rapid process of water reform in Australia has seen governments rely heavily on ‘expert’ or ‘scientific’ panel advice for river condition and environmental flow assessments. These multi‐disciplinary teams of scientists have enabled a quick and relatively inexpensive injection of science into what is often a data‐poor decision process. However, expert panels suffer from several important drawbacks including a lack of transparency and repeatability, and unquantified uncertainty. In the case of the Snowy Mountains hydro‐electric scheme, a government initiative to corporatize the government‐owned authority led to the establishment of the Snowy Water Inquiry (SWI) that was required by law to propose and evaluate (within a six month period) a range of options for future river regulation, diversion and environmental flows. A Scientific Reference Panel (SRP) was therefore established to assess current (1998) river condition and to assess the likely environments benefits of a range of environmental flow options. The SRP attempted to overcome a number of the typical shortcomings of the expert panel approach by (i) integrating available data with expert opinion in its assessments, and (ii) developing a composite River Condition Index (RCI) underpinned by a conceptual framework that links habitat and biotic condition and comprises several sub‐indices that translate qualitative assessments (relative to a pre‐disturbance reference condition) into numeric values in a transparent and repeatable manner. The SRP estimated the level of uncertainty associated with its various assessments, and used these to quantify uncertainty estimates on RCI values. In this paper the RCI is described and its use is illustrated through presentation of the assessments of current (1998) river condition and the associated uncertainty analyses that were made for the rivers in the Snowy Mountains area. The results suggest that in spite of high levels of uncertainty associated with individual assessments, the SRP was able to demonstrate significant difference in current condition between rivers, and in likely future condition between different environmental flow scenarios. Although further investigations and lengthy negotiations occurred subsequent to the SWI to achieve corporatization, the environmental assessments made in the SWI provided the most comprehensive source of information available to governments and the community regarding the likely environmental outcomes of the proposed changes. Subsequent to the SWI the scenario‐based approach to environmental flow assessment has become increasingly common internationally, and major Australian river condition assessments have adopted a similar conceptual framework to the RCI. Copyright © 2004 John Wiley & Sons, Ltd.     

Uncertainty Analysis of Bivariate Design Flood Estimation and its Impacts on Reservoir Routing

The bivariate hydrological quantile estimation may inevitably induce large sampling uncertainty due to short sample size. It is crucial to quantify such uncertainty and its impacts on reservoir routing. In this study, a copula-based parametric bootstrapping uncertainty (C-PBU) method is proposed to characterize the bivariate quantile estimation uncertainty and the impact of such uncertainty on the highest reservoir water level is also investigated. The Geheyan reservoir in China is selected as a case study. Four evaluation indexes, i.e. area of confidence region, mean horizontal deviation, mean vertical deviation and average Euclidean distance, are adopted to quantify the quantile estimation uncertainty. The results indicate that the uncertainty of quantile estimation and the highest reservoir water level increases with larger return period. The 90% confidence interval (CI) of highest reservoir water level reaches 1.56 m and 2.52 m under 20-year and 50-year JRP respectively for the sample size of 100. It is also indicated that the peak over threshold (POT) sampling method contribute to uncertainty reduction comparing with the annual maximum (AM) method. This study could provide not only the point estimator of design floods and corresponding design water level, but also the rich uncertainty information (e.g. 90% confidence interval) for the references of reservoir flood risk assessment, scheduling and management.     

河流连通性综合评价方法研究

保障河流连通性是生态系统保护与修复的一项重要举措,为推进我国江河湖库水系连通工作,亟需加强河流连通性评价的理论方法研究。基于河流生态系统四维结构和功能整体模型,构建了河流连通性综合评价方法;通过梳理国内外河流连通性评价的研究和实践,从4个维度凝练了构建河流连通性指数的5个评价指标,包括破碎度指数、库容调节系数、水资源利用消耗率、路网密度和城市夜间灯光指数;通过综合分析各个指标的阈值和权重,建立了河流连通性指数计算方法、综合评价方法及评价依据。研究成果进一步完善了河流连通性评价的理论方法,为河流连通性评价提供了一种新的思路,可为河流生态系统保护与修复提供参考。     

鱼类栖息地环境评价指标体系初探

根据鱼类洄游、产卵和越冬等生命周期中的水环境状况、水文情势、水动力特性及地形特征等要素将影响鱼类栖息地的若干指标分成水质指标、水文学指标、水力学指标及河流地形指标。并通过分析各项指标的生态学意义,筛选出其中若干与鱼类生活、繁殖相关的评价指标。最终建立了包含目标层、要素层、特征层和指标层4个层次的鱼类栖息地环境评价指标体系,该体系以保护鱼类栖息地为目标,包含4类要素、13类特征共46项指标,可为河流栖息地评价及鱼类保护提供重要依据。     

基于GLUE的新安江模型参数不确定性分析及应用

结合新安江模型在东洋河流域的应用,提出了基于GLUE方法的新安江模型参数不确定性分析。采用GLUE算法抽样结果对东洋河流域进行不确定性预报,选用水文模拟中常用的确定性系数作为似然判据,通过设定0.7为阀值,得到的90%置信区间的流量过程,实例研究表明,以该结果进行不确定预报是可行的。     

Uncertainty Intercomparison of Different Hydrological Models in Simulating Extreme Flows

A growing number of investigations on uncertainty quantification for hydrological models have been widely reported in past years. However, limited studies are found on uncertainty assessment in simulating streamflow extremes so far. This article presents an intercomparison of uncertainty assessment of three different well-known hydrological models in simulating extreme streamflows using the approach of generalized likelihood uncertainty estimation (GLUE). Results indicate that: (1) The three modified hydrological models can reproduce daily streamflow series with acceptable accuracy. When the threshold value used to select behavioral parameter sets is 0.7, XAJ model generates the best GLUE estimates in simulating daily flows. However, the percentage of observations contained in the calculated 95 % confidence intervals (P-95CI) is low (<50 %) when simulating the high-flow index (Q10). (2) Decreasing average relative length (ARIL), P-95CI and increasing average asymmetry degree (AAD) are found, when the threshold value increases for both daily-flows and high-flows. However, there is a significant inconsistence between sensitivity of daily-flows and high-flows to various threshold values of the likelihood function. Uncertainty sources from parameter sets, model structure and inputs collectively accounts for above sensitivity. (3) The best hydrological model in simulating daily-flows is not identical under different threshold values. High P-95CIs of GLUE estimate for high-flows (Q10 and Q25) indicate that TOPMODEL generally performs best under different threshold values, while XAJ model produces the smallest ARIL under different threshold values. The results are expected to contribute toward knowledge improvement on uncertainty behaviors in simulating streamflow extremes by a variety of hydrological models.     

Water Quality Assessment of the Santiago River and Attenuation Capacity of Pollutants Downstream Guadalajara City,Mexico

The Santiago River in Mexico has been seriously polluted because of rapid urbanization and industrialization activities, lacking of appropriate planning and contamination monitoring policies. This research characterized the river water quality and recognizes some overall pollution sources, using two different information references: a dataset of 5 years from the Jalisco State Water Commission and a 14‐year dataset from the National Water Commission. Two zones have been identified as the main sources of pollution (hotspots), where the major events of urban and industrial wastewater discharges occur: (i) the urban fringe of Guadalajara city, with special emphasis in its southern area (nearby the so‐called El Ahogado stream) and (ii) downstream of Guadalajara City. Nevertheless, we have recognized some areas along the Santiago River where significant reduction of pollutants concentration takes place, possibly due to dilution by the inflow of tributaries and to the rainfall increasing. In addition, it is likely that hydropower dams are positively influencing the retention of pollutants along the river. In the lower zone, the water concentrations of O₂ are consistently above acceptable levels (up to 5 mg L^?1), and the majority of the pollution indicators parameters are below the maximum permissible values, despite the high pollution in Guadalajara area. This paper attempts to offer a methodological approach for a more accurate assessment of the river water quality and may assist in interpreting the sampling results derived from the regular monitoring, conducted by the state water authorities, while emphasizing the natural attenuation capacity of the Santiago River. Copyright © 2015 John Wiley & Sons, Ltd.     

河流功能性指标的研究进展及应用

河流健康指标是评价河流健康状况和河流生态系统完整性的标尺,是准确、全面评价河流生态系统健康状况的基础。国内现有河流健康指标大多针对河流生态系统的结构性,而对河流的功能性关注不多。本文系统综述了国外河流功能性指标的研究进展与应用现状,并对两种的典型功能性指标的应用方法和评价标准进行介绍。以日本大山川减水河段环境流量修复为案例,使用典型功能性指标和结构性指标对环境流量修复效果进行评价,结果表明河流功能性指标能更好地反映河流生态系统对流量变动的响应。本文研究成果可为完善我国河流健康评估体系提供借鉴。     

河流系统健康体系及评价方法研究

考虑反映河流系统的动力状况、水质状况、河流地貌和生物指标状况、河流服务状况等4个方面，构建了河流系统健康体系。建立了基于模糊理论的河流健康状况多层次评价模型，给出了相应的评价指标、标准和权重。以海河三岔口河段为例，应用已建的河流系统健康状况模糊综合评价模型，对河流系统的健康状况进行了评价。结果表明，该评价体系能定量地从各层次分项指标和总体角度反映河流健康状况，可为河流管理和生态修复工程提供技术支持。     

基于无监督特征学习的水电机组健康状态实时评价方法

水电机组健康状态实时评价是状态监测和劣化预警中的重要内容,传统方法采用单一限值比较,不能体现机组个性特色,且适用机组运行工况有限.同时,现阶段已知的水电机组故障类型有限,缺乏故障样本,限制了有监督特征学习方法的实际应用.本文提出了以无监督特征学习技术构建水电机组健康状态劣化指标的新方法,充分利用水电机组状态监测系统中海...     

When does a stream become a river?

The distinction between a “stream” and “river” is imprecise and vague despite the popular usage of the terms across disciplines for describing flowing waterbodies. Based on an analysis of named flowing waterbodies in the continental United States, we suggest a bank-to-bank channel width of 15 m as a working threshold in defining smaller “streams” from larger “rivers.”     

Monitoring of environmental flow outcomes in a large river basin: The Commonwealth Environmental Water Holder's long‐term intervention in the Murray–Darling Basin,Australia

The Murray–Darling Basin in south‐eastern Australia contains over 70,000 km² of wetlands and floodplains, many of which are in poor condition. In response, Australian governments have committed to a major restoration program, the Murray–Darling Basin Plan that includes management of 2,750 Gl of environmental water to protect and restore aquatic ecosystems. The restoration is being undertaken within an adaptive management framework that includes monitoring the outcomes of environmental flows in seven river valleys. This paper provides an overview of the 5‐year monitoring project and some preliminary results. Monitoring design considered the Basin Plan's environmental objectives, conceptual models of ecosystem responses to flow, and an outcomes framework linking flow responses to the environmental objectives. Monitoring indicators includes ecosystem type, vegetation, river metabolism, and fish. Responses are evaluated to identify the contribution of environmental flows to Basin Plan environmental objectives and continual improvements in management. The program is unique in that it seeks to monitor long‐term outcomes of environmental flows at the river basin scale. Despite many challenges, the monitoring has become a key part of the adaptive management of environmental flows in the Murray–Darling Basin.     

五元联系数在黄河健康评价中的应用

河流健康系统是由众多不确定性和复杂性因素组成的,五元联系数是集对分析中同异反联系数的推广,它可更深入地分析系统中的各种不确定性。用层次分析法确定指标权重,从主客观两方面定量计算河流健康程度,将五元联系数应用于黄河健康系统的评价,用联系度可描述评价对象与评价标准之间的关系,其结果简便直观,能清晰地反映评价对象和评价标准间的联系。得到河流健康评价等级为"亚健康",其结果与有序度熵的河流健康评价方法所得结果一致。     

Site length for biological assessment of boatable rivers

There is increasing international interest by water resource management agencies worldwide in developing the capacity for quantitative bioassessments of boatable rivers. This interest stems from legal mandates requiring assessments, plus growing recognition of the threats to such systems from multiple and co‐varying stressors (e.g. chemical pollutants, physical habitat alterations, altered flow regimes, channel modifications and alien species). The elevated cost and inefficiencies of jurisdictionally‐ and taxonomically‐segregated assessments is widely recognized, as is the desire to obtain comparable data that can be easily shared among political jurisdictions and ecological regions. The objectives, sampling methods, indicators, site‐scale sampling designs and geographic extent of the resources being sampled differ among programmes, thereby limiting such data exchanges. Our objective in this paper is to review major biological assessment design alternatives for boatable rivers, with special attention given to the sample site length from which data are collected. We suggest that sufficient site length determinations should be based on the survey objectives, the relative heterogeneity of the habitat template, and the quality of data necessary for meeting programmatic data quality objectives. Future sampling effort studies should be designed to allow separate samples of several short sub‐sites at many diverse sites to generate multiple data points for each site. Data from those multiple sub‐sites should be analysed using randomization‐based data evaluation methods. We hope that our recommendations will be useful to the maximum number of institutions, including those with limited funds and a purely local focus, as well as those responsible for sampling at continental geographic extents. Copyright © 2010 John Wiley & Sons, Ltd.     

AHP法在河岸发展与河川管理评估方法之研究

台湾地区近年来经济发展促使国民对河川区域内土地利用及休闲游憩空间的需求也相应增加,为能适度开发该土地之经济价值,且在不影响河防安全之前提下,民众可依水利法及河川管理办法相关规定向河川管理机关申请许可使用,因此目前河川区域实际已是在多元利用中.本研究为探讨河川相关使用行为及亲水性活动之合适性,确立河川区域内使用行为评估体系,并运用多评准决策之分析阶层程序法(AHP),针对河防安全考虑、生态及自然环境维护及人文环境等条件提出一套评定量化的评估方法,建立评定各类许可使用行为对河防安全及河川环境维护之评估指数.研究结果显示,应用本文所提出之评估方法对于目前各种使用行为进行定性定量评估,显示评估后之指数分布情形,亦切实反应台湾河川目前实务管理现况情形.     

河流系统健康状况评价体系及评价方法

考虑反映河流系统的动力状况、水质状况、河流地貌和生物指标状况、河流服务状况等4个方面,构建了河流系统健康状况评价体系。建立了基于模糊理论的河流健康状况多层次评价模型,给出了相应的评价指标、标准和权重。以海河三岔口河段为例,应用已建的河流系统健康状况模糊综合评价模型,对河流系统的健康状况进行了评价。计算结果表明,该评价体系能定量地从各层次分项指标和总体角度反映河流健康状况,可为河流管理和生态修复工程提供技术支持。     

Evaluating Uncertainty in Physical Habitat Modelling in a High‐Gradient Mountain Stream

Predictions of habitat‐based assessment methods that are used to determine instream flow requirements for aquatic biota are uncertain, but instream flow practitioners and managers often ignore those uncertainties. Two commonly recognized uncertainties arise from (i) estimating the way in which physical habitat within a river changes with discharge and (ii) the suitability of certain types of physical habitat for organisms. We explored how these sources of uncertainty affect confidence in the results of the British Columbia Instream Flow Methodology (BCIFM), which is a commonly used transect‐based habitat assessment tool for small‐scale water diversions. We calculated the chance of different magnitudes of habitat loss resulting from water diversion using a high‐gradient reach of the North Alouette River, BC, as a case study. We found that uncertainty in habitat suitability indices for juvenile rainbow trout generally dominated uncertainty in the results of the BCIFM when large (>15) numbers of transects were used. In contrast, with small numbers of transects, variation in physical habitat among sampled transects was the major source of uncertainty in the results of the BCIFM. Presentations of results of the BCIFM in terms of probabilities of different amounts of habitat loss for a given flow can help managers prescribe instream flow requirements based on their risk tolerance for fish habitat loss. Copyright © 2015 John Wiley & Sons, Ltd.     

强感潮河网生态治理工程综合评价

崇明岛河网的水资源调度和水动力体系完全受长江口潮汐的控制,河网中水体水质、生物也受长江的影响。为评价强感潮河网治理后的生态建康状况,在分析强感潮区河流特点的基础上提出了结构简单、数据易于收集的生态健康评价指标体系,包括水利指标群、河岸稳定指标群、水质水量指标群和生态指标群,共23个指标,并建立了各指标的定量标准。利用所建立的评价指标体系采用模糊综合评价法对崇明县陈家镇河网的四号河生态工程修复规划进行生态健康状态评价。评价结果表明四号河经生态修复后为生态达标河道。所提出的评价指标系体系和评价方法可为感潮河网的生态健康评价提供参考。