Landsat mapping of annual inundation (1979–2006) of the Macquarie Marshes in semi-arid Australia

Measuring inundation over long timeframes is essential for understanding the responses of large floodplain wetlands on regulated rivers, such as the internationally Ramsar listed Macquarie Marshes (2000 km²) in central-eastern Australia. We used near-spring Landsat images (Multispectral Scanner (MSS) and Thematic Mapper (TM) imagery) over 28 years (1979–2006) and classified for inundation, integrating water and vegetation response using Iterative Self-Organizing Data Analysis (ISODATA) clustering. A spatially explicit inundation index showed that zones inundated with high frequency were mostly in the northern region. Change detection of inundation indices over three consecutive water management periods (period 1 (1979–1987), period 2 (1988–1996) and period 3 (1997–2006)) showed that zones inundated with high frequency across the Macquarie Marshes contracted, equating to the loss of three or more spring floods from each 9-year period, despite no corresponding change in annual catchment or local rainfall. Landsat represents the only effective available long-term information for analysing long-term changes in inundation patterns of floodplain wetlands.     

A mixing criterion for turbid rivers

A criterion for the formation/destruction of thermal stratification in turbid rivers is developed and tested against an extensive data set in a weir pool on the Murrumbidgee River, Australia. The criterion estimates whether a river section would stratify or not, subject to a prescribed heat flux through the water surface and a prescribed river flow. It can be determined from readily accessible parameters, including solar radiation, turbidity, wind speed and river discharge.It is suggested that this simple mixing criterion be used as a flow management tool in a variety of water quality applications in rivers.     

重点河湖控制断面生态流量监测预警系统设计及应用

针对我国河湖生态安全保障面临严峻形势,现有生态流量监测系统存在覆盖河湖范围有限、预报不及时等问题,为进一步加强河湖生态流量管理,基于水利部国家水资源监控管理信息平台,依托其水资源数据库、水文实时雨水情数据库、水利部一张图服务及管理信息等数据,设计和研发全国重点河湖控制断面生态流量监测预警系统。生态流量监测预警系统包括生态流量断面的基础信息、实时监测数据、指标值及阈值告警的综合展示,以及生态流量达标情况判别等功能。目前,生态流量监测预警系统已接入全国重点河湖104个控制断面,断面生态流量满足程度达到96.2%;龙川监测断面分析结果显示,自 2021 年 1 月以来该断面生态流量满足情况差于 2020 年同期,与取用水量增加及天然来水减少存在一定联系,可为保障重点河湖控制断面生态流量提供有力信息支撑。     

A geospatial framework to support integrated biogeochemical modelling in the United Kingdom

Anthropogenic impacts on the aquatic environment, especially in the context of nutrients, provide a major challenge for water resource management. The heterogeneous nature of policy relevant management units (e.g. catchments), in terms of environmental controls on nutrient source and transport, leads to the need for holistic management. However, current strategies are limited by current understanding and knowledge that is transferable between spatial scales and landscape typologies. This study presents a spatially-explicit framework to support the modelling of nutrients from land to water, encompassing environmental and spatial complexities. The framework recognises nine homogeneous landscape units, distinct in terms of sensitivity of nutrient losses to waterbodies. The functionality of the framework is demonstrated by supporting an exemplar nutrient model, applied within the Environmental Virtual Observatory pilot (EVOp) cloud cyber-infrastructure. We demonstrate scope for the use of the framework as a management decision support tool and for further development of integrated biogeochemical modelling.     

移动雷达波测流系统在松柏水文站的运用

针对松柏水文站在发生暴雨洪水时河流陡涨陡落,高洪时漂浮物多,采用流速仪或ADCP测流不安全的问题,应用移动雷达波测流系统进行流量测验。在分析测流系统组成、工作原理、管理软件的基础上,按照不同水位级布置测次,采用同期测流系统施测流量与转子式流速仪人工实测流量进行比测,建立2种流量相关关系,率定测流系统流量系数,并进行误差分析评判,验证移动雷达波测流系统测流精度。比测率定结果表明:两者相关关系良好,移动雷达波测流系统测得的水面流速经率定后,推算的断面流量精度较高,满足水文资料整编精度及水资源管理要求,可提高水文资料时效性和准确性,解决山溪性河流流量测验安全问题。     

A comparison between neural-network forecasting techniques-casestudy: river flow forecasting

Estimating the flows of rivers can have significant economic impact, as this can help in agricultural water management and in protection from water shortages and possible flood damage. The first goal of the paper is to apply neural networks to the problem of forecasting the flow of the River Nile in Egypt. The second goal of the paper is to utilize time series as a benchmark to compare between several neural-network forecasting methods. We compare four different methods to preprocess the inputs and outputs, including a novel method proposed here based on discrete Fourier series. We also compare three different methods for the multistep ahead forecast problem: the direct method, the recursive method, and the recursive method trained using a backpropagation through time scheme. We also include a theoretical comparison between these three methods. The final comparison is between different methods to perform a longer horizon forecast, and that includes ways to partition the problem into several subproblems of forecasting K steps ahead.     

A computational tool for the characterisation of rapid fluctuations in flow and stage in rivers caused by hydropeaking

Power production by hydro-electric plants in response to short-term variations in the energy demand and market (hydropeaking) may lead to frequent and rapid fluctuations in flow and stage in rivers downstream of power plant outlets. We have developed a time series analysis tool designed to quantify these rapid fluctuations. They were identified by establishing river- and data-specific thresholds both for the rates of change in flow or stage, and for other peaking event parameters. In contrast to previous similar analyses, we separated peaking events into rapid increases and rapid decreases. We also analysed other parameters such as daylight conditions during peaking events, and calculated both mean and maximum rates of change in flow and stage. The results of such analysis in a Norwegian river were used to demonstrate outputs from the tool. Our tool may be useful with respect to environmental impact assessment and mitigation related to stream hydropeaking.     

An integrated modelling framework for regulated river systems

Management of regulated water systems has become increasingly complex due to rapid socio-economic growth and environmental changes in river basins over recent decades. This paper introduces the Source Integrated Modelling System (IMS), and describes the individual modelling components and how they are integrated within it. It also describes the methods employed for tracking and assessment of uncertainties, as well as presenting outcomes of two case study applications.Traditionally, the mathematical tools for water resources planning and management were generally designed for sectoral applications with, for example, groundwater being modelled separately from surface water. With the increasing complexity of water resources management in the 21st century those tools are becoming outmoded. Water management organisations are increasingly looking for new generation tools that allow integration across domains to assist their decision making processes for short-term operations and long-term planning; not only to meet current needs, but those of the future as well.In response to the need for an integrated tool in the water industry in Australia, the eWater Cooperative Research Centre (CRC) has developed a new generation software package called the Source IMS. The Source IMS is an integrated modelling environment containing algorithms and approaches that allow defensible predictions of water flow and constituents from catchment sources to river outlets at the sea. It is designed and developed to provide a transparent, robust and repeatable approach to underpin a wide range of water planning and management purposes. It can be used to develop water sharing plans and underpin daily river operations, as well as be used for assessments on water quantity and quality due to changes in: i) land-use and climate; ii) demands (irrigation, urban, ecological); iii) infrastructure, such as weirs and reservoirs; iv) management rules that might be associated with these; and v) the impacts of all of the above on various ecological indices. The Source IMS integrates the existing knowledge and modelling capabilities used by different state and federal water agencies across Australia and has additional functionality required for the river system models that will underpin the next round of water sharing plans in the country. It is built in a flexible modelling environment to allow stakeholders to incorporate new scientific knowledge and modelling methods as they evolve, and is designed as a generic tool suitable for use across different jurisdictions. Due to its structure, the platform can be extended/customised for use in other countries and basins, particularly where there are boundary issues.     

Mean–variance relationship of the number of flows in traffic aggregation and its application to traffic management

We consider the mean–variance relationship of the number of flows in traffic aggregation, where flows are divided into several groups randomly, based on a predefined flow aggregation index, such as source IP address. We first derive a quadratic relationship between the mean and the variance of the number of flows belonging to a randomly chosen traffic aggregation group. Note here that the result is applicable to sampled flows obtained through packet sampling. We then show that our analytically derived mean–variance relationship fits well those in actual packet trace data sets. Next, we present two applications of the mean–variance relationship to traffic management. One is an application to detecting network anomalies through monitoring a time series of traffic. Using the mean–variance relationship, we determine the traffic aggregation level in traffic monitoring so that it meets two predefined requirements on false positive and false negative ratios simultaneously. The other is an application to load balancing among network equipments that require per-flow management. We utilize the mean–variance relationship for estimating the processing capability required in each network equipment.     

Development of an environmental flows decision support system

The Murray–Darling Basin in Australia is severely environmentally degraded as a result of a range of anthropogenic changes, most notably the regulation and extraction of surface water resources for irrigated agriculture. Environmental problems include eutrophication of rivers and storages, elevated salinity levels, widespread blooms of toxic blue–green algae, decline of native fish and bird populations, and reduction of area of riverine wetlands. Both the community and the government are committed to improving the state of the environment in the Basin, both for it's intrinsic ecological values, and to ensure the sustainability of production in what is Australia's most economically important agricultural region. To facilitate the on-going trade-off process between competing users of this resource, a decision support system (DSS) is being developed which will enable explicit prediction of the likely response of key features of the riverine environment to proposed flow management scenarios. The DSS is being developed using the RAISON shell (Lam, D.C.L., Mayfield, C.I., Swayne, D.A., Hopkins, K., 1994. A prototype information system for watershed management and planning. Journal of Biological Systems 2 (4), 499–517), and will integrate a range of simple models of riverine ecology which are being developed. These models will include qualitative and quantitative models representing the response of different aspects of the instream and floodplain ecology dependent upon the river flow regime. The DSS will not include a detailed model of river hydrology or hydraulics, but rather, will use the output from the range of such models currently in use in the Basin as inputs to the ecological models. The DSS will also provide a range of tools to allow user-defined evaluation of scenario results, as well as explanations and supporting information to elucidate the ecological modelling.     

侧扫雷达测流系统开发与应用

河流流量是水文水资源管理中最重要的参数之一,目前大多采用接触式测流,安装使用较为复杂,灵活性较差。利用雷达遥感技术对河流进行实时监测,研制出侧扫雷达测流系统,依据布拉格散射和多普勒原理测量河流的表面流速,使用这些数据及已知的河流横截面图(深度分布)和已测的水位计算出河流流量。侧扫雷达测流系统采用太阳能供电和移动蜂窝通信,流速测量、数据上传、流量合成无需人工干预,可实现河水流量的自动化监测。结果表明,侧扫雷达测流系统适用于各种复杂环境情况,能滤除船舶、周边建筑、陆地移动汽车等构成的雷达回波干扰,最大探测距离可达800 m以上,适用于内陆河流、界河、大江大湖等天然流域的流量监测。     

Linking groundwater simulation and reservoir system analysis models: The case for California’s Central Valley

Groundwater is an important resource. In many developed basins it meets part or all of the water demands. In addition, the management of groundwater resources directly impacts stream flows through stream-aquifer interactions. Yet many reservoir system analysis models that are used for the management of surface water resources either include a simplified representation of the groundwater flow dynamics or rely on surrogate models (linear response functions, artificial neural networks, etc.) which are trained using more complex groundwater models. These approaches may introduce restrictive, sometimes inaccurate, representation of the groundwater flow dynamics and additional modeling steps. In this study a reservoir system analysis model that utilizes an LP solver is linked directly to a non-linear, three-dimensional, finite element groundwater model. The linked model is a general-purpose model and can be applied to any basin. Some of the features of the linked model are showcased by an application to California's Central Valley.     

Simulation of floating bodies with the lattice Boltzmann method

This paper is devoted to the simulation of floating rigid bodies in free surface flows. For that, a lattice Boltzmann based model for liquid–gas–solid flows is presented. The approach is built upon previous work for the simulation of liquid–solid particle suspensions on the one hand, and on an interface-capturing technique for liquid–gas free surface flows on the other. The incompressible liquid flow is approximated by a lattice Boltzmann scheme, while the dynamics of the compressible gas are neglected. We show how the particle model and the interface capturing technique can be combined by a novel set of dynamic cell conversion rules. We also evaluate the behaviour of the free surface–particle interaction in simulations. One test case is the rotational stability of non-spherical rigid bodies floating on a plane water surface–a classical hydrostatic problem known from naval architecture. We show the consistency of our method in this kind of flows and obtain convergence towards the ideal solution for the heeling stability of a floating box.     

An environmental assessment system for environmental technologies

A new model for the environmental assessment of environmental technologies, EASETECH, has been developed. The primary aim of EASETECH is to perform life-cycle assessment (LCA) of complex systems handling heterogeneous material flows. The objectives of this paper are to describe the EASETECH framework and the calculation structure. The main novelties compared to other LCA software are as follows. First, the focus is put on material flow modelling, as each flow is characterised as a mix of material fractions with different properties and flow compositions are computed as a basis for the LCA calculations. Second, the tool has been designed to allow for the easy set-up of scenarios by using a toolbox, the processes within which can handle heterogeneous material flows in different ways and have different emission calculations. Finally, tools for uncertainty analysis are provided, enabling the user to parameterise systems fully and propagate probability distributions through Monte Carlo analysis.     

An integrative modelling approach for linking environmental flow management,ecosystem service provision and inter-stakeholder conflict

Fifteen water flow-dependent ecosystem services (ES) are modelled for the case of the Ter (Catalonia, Spain), a river with persisting intra- and inter-basin conflicts on water flows. The aim is to analyse ES response (and ensuing social reaction) to changes in water flow management, in a context of several tradeoffs and synergies driven by access to water use.We argue for a new modelling approach to integrate diverse values and perspectives through engaging with stakeholders' concerns and claims. This is done under different conditions, including droughts, wet years, and different options for managing flows. Our approach involves two stages, namely water allocation modelling, including scenario development, and ES provision modelling, including participatory design of service suitability curves. The method presented allows analysing spatial/temporal patterns and ES performance. The paper explains methodological innovation and its application to highlight the role of recurrent socio-environmental conflicts in water management decisions.     

Equations and their physical interpretation in numerical modeling of heavy metals in fluvial rivers

Based on the previous work on the transport-transformation of heavy metal pollutants in fluvial rivers, this paper presented the formulation of a two-dimensional model to describe heavy metal transport-transformation in fluvial rivers by considering basic principles of environmental chemistry, hydraulics, mechanics of sediment transport and recent developments along with three very simplified test cases. The model consists of water flow governing equations, sediment transport governing equations, transport-...     

Toward improved simulation of river operations through integration with a hydrologic model

Advanced modeling tools are needed for informed water resources planning and management. Two classes of modeling tools are often used to this end–(1) distributed-parameter hydrologic models for quantifying supply and (2) river-operation models for sorting out demands under rule-based systems such as the prior-appropriation doctrine. Within each of these two broad classes of models, there are many software tools that excel at simulating the processes specific to each discipline, but have historically over-simplified, or at worse completely neglected, aspects of the other. As a result, water managers reliant on river-operation models for administering water resources need improved tools for representing spatially and temporally varying groundwater resources in conjunctive-use systems. A new tool is described that improves the representation of groundwater/surface-water (GW-SW) interaction within a river-operations modeling context and, in so doing, advances evaluation of system-wide hydrologic consequences of new or altered management regimes.     

Estimation of real-time demands on the basis of pressure measurements by different optimization methods

The aim was to estimate real-time demands in a water distribution system on the basis of pressure measurements. The task was formulated as an optimization procedure to find water flows correcting typical demands that will minimize differences between measured and modelled pressures. The Levenberg–Marquardt algorithm (LMA) and the Genetic algorithm (GA) were tested to solve the problem. Results showed that the LMA works much faster than the GA. It was also found that the higher the demands the lower is the sensitivity of the results to random errors in pressure measurements. Measurements in an operational WDS were used in calculations.     

Developing real time operating rules for trading discharge permits in rivers: Application of Bayesian Networks

Transferable discharge permit (TDP) programs show potential cost-effective methods of pollution control in river systems. Nevertheless, there remain uncertainties that, if not adequately addressed, might impair their success. Trading Ratio System (TRS) suggested by Hung and Shaw [2005. A trading-ratio system for trading water pollution discharge permits. Journal of Environmental Economics and Management 49, 83–102] is a cost-effective tool for water quality management in river systems, which provides the optimum trading pattern among dischargers. TRS has been designed for a single conservative water quality variable and the existing uncertainties are not incorporated. In this study, TRS is extended to be applicable to Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO) management in river systems and uncertainties in input variables of river water quality simulation model are also considered. In the proposed methodology, low water quality is also quantified as a fuzzy event and fuzzy risk of violating the water quality standards is estimated at each checkpoint along the river. The Extended Trading Ratio System (ETRS) is used in a Monte Carlo Analysis to provide the required data for training and validating a Bayesian Network (BN). The trained BN can be used for real time river water quality management and provides the probability density functions of treatment levels and trading discharge permit policies. The methodology is successfully applied to the Zarjub River in the northern part of Iran to show its usefulness as a cost-effective and risk-informed decision-making tool in real time river water quality management.