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Tipping bucket rain gauges (TBRs) have been, and apparently will continue to be one of the most widely used pieces of equipment for rainfall monitoring, being frequently used for the calibration, validation and downscaling of radar and remote sensing data, due to their major advantages–low cost, simplicity, and low energy consumption. Thus, many works have focused and continue to focus on their main disadvantage–measurement biases (mainly in wind and mechanical underestimations). However, despite arduous scientific effort, calibration methodologies are not frequently implemented by monitoring networks operators or data users, propagating bias in databases and in the different applications of such data, causing uncertainty in the modeling, management, and forecasting in hydrological research, mainly due to a lack of knowledge. Within this context, this work presents a review of the scientific advances in TBR measurement uncertainties, calibration, and error reduction strategies from a hydrological point of view, by describing different rainfall monitoring techniques in Section 2, summarizing TBR measurement uncertainties in Section 3, focusing on calibration, and error reduction strategies in Section 4, a discussion and perspectives in Section 5, and conclusions in Section 6, providing an overview of the of the state of the art and future perspectives of the technology.

We live in a world of rapid social, economic and ecosystem change, facing major environmental challenges such as global warming, biodiversity loss and pressures on natural resources. Addressing these topics requires world-class ecosystem research by a well-connected, extensive community of experts, supported by advanced sites and facilities, openly shared and easily accessible data and capacity building programs. This is the goal of the Integrated European Long-Term Ecosystem, critical zone and socio-ecological system Research Infrastructure (eLTER RI). eLTER RI will adopt a fundamentally systemic approach to observe and analyse the environmental system, encompassing biological, geological, hydrological and socio-ecological perspectives. It will be the first research infrastructure capturing and analysing holistically the integrated impacts of climate change alongside other pressures on a wide variety of European ecosystems. Ca. 200 eLTER research sites will provide a wide scale and systematic coverage of major European terrestrial, freshwater and transitional water ecosystem. eLTER RI will allow in-situ, co-located gathering of Essential Variables ranging from bio-physico-chemical to biodiversity and socio-ecological data. Ecosystem change caused by long-term pressures and short-term pulses will be investigated in a nested design from the local to the continental scale. With the huge number of in-situ sites and platforms and the harmonized and standardized observation concept, the eLTER RI offers outstanding new perspectives for hydrological research in Europe. One of the major aims of long term ecosystem monitoring and research is to provide quality controlled and reliable data to support scientific analyses and enable input for designing environmental policies and assessing their impacts. Both the concept and in-situ design as well as the basic architectures and tools of the eLTER RI to support data providers and data users will be presented.

Global hydrological models are used for understanding, monitoring, and forecasting the global freshwater system. Their outputs provide crucial water-related information for various audiences, such as scientists and policymakers. WaterGAP is such a global hydrological model, and it has been utilized extensively to assess water scarcity for humans and ecologically relevant streamflow characteristics, considering the impacts of human water use and man-made reservoirs as well as of climate change.The WaterGAP research software has been developed and modified by researchers with diverse programming backgrounds for over 30 years. During this time, there has been no clear-cut protocol for software development and no defined software architecture; hence the current state of the software is a collection of over a thousand lines of code with little modularity and documentation. As a result, it is challenging for new model developers to understand the current software and improve or extend the model algorithm. Also, it is almost impossible to make the software available to other researchers (e.g., For the reproduction of research results).Here we present ReWaterGAP, an ongoing project to redevelop WaterGAP into a sustainable research software (SRS). We define SRS as software that (1) is maintainable, (2) is extensible, (3) is flexible (adapts to user requirements), (4) has a defined software architecture, (5) has a comprehensive in-code and external documentation, and (6) is accessible (the software is licensed as Open Source with a DOI (digital object identifier) for proper attribution). The goal is to completely rewrite the software WaterGAP from scratch with a modular structure using a modern programming language and state-of-the-art software architecture, and to provide extensive documentation so that the resulting software fulfills the requirements of a SRS while maintaining good computational performance.In our presentation, we provide insights into our ongoing reprogramming, outline milestones, and provide an overview of applied best practices from the computer science community (such as internal and external code review, test-driven development, and agile development methods). We plan to share the software development lessons we have learned along the way with the scientific community to help them improve their software.

As a consequence of global change, forests worldwide are undergoing a restructuring process. The expectations for forests of the future are ambitious: Providing resilient forest ecosystems that capture large amounts of carbon but also provide stable groundwater recharge rates. To balance the interests of both forestry and water management authorities, scientists and practitioners need to be able to investigate and predict which forest types and combinations of tree species are most likely to fulfill these needs.Methods based on the analysis water stable isotopes have been used extensively for studying water uptake depths of vegetation, groundwater recharge, transit times, and water sources in general. Despite being arguably the superior tool when not only amounts but also knowledge of the sources of an (eco-)hydrological flux are needed, the highly dynamic nature of water transport processes within the soil-plant-atmosphere continuum (SPAC) could hardly be captured in the past. With the advent of laser spectroscopy in the last decade, we are now able to measure water stable isotopes continuously and in all compartments of the SPAC.In this keynote, we present and review the most recent advances (2016-now) of combined soil and plant in-situ water isotope measurements carried out in different ecosystems worldwide. We then critically discuss the gain in process-understanding of in-situ monitoring approaches and demonstrate how in-situ methods could be integrated with traditional and novel methods to advance forest hydrology.In-situ and semi-in-situ (i.e., sampling of water vapor) water stable isotope methods have been greatly improved within the last five years. Initial disadvantages (e.g., comparability to traditional methods, complicated & laborious setup & maintenance, expensive) have been carefully addressed, and improvements have been implemented. Recent research has proven that i.) highly dynamic and heterogenous processes (e.g., stem flow, groundwater recharge through preferential pathways, change of uptake depths in response to rainfall/drought, disentangling water use of different tree species in mixed forests) can be captured exceptionally well using in-situ isotope methods; ii.) water-vapor equilibration methods represent the isotope composition of mobile water better compared to destructive methods, and iii.) using continuous water isotope data reduces parameter uncertainties in SPAC modeling.In summary, we state that the benefits of using in-situ or semi in-situ techniques outweigh the disadvantages by far and strongly encourage the water stable isotope community to integrate them regularly into studies of dynamic soil-plant-atmosphere feedbacks.

The UK is planning to implement a £38M (€43M) Flood and Drought Research Infrastructure to facilitate the hydrological science and innovation needed to underpin the UK’s adaptation and resilience to floods and droughts. The UKRI’s intent to invest from its infrastructure fund was published following a ~2-year scoping study that determined research community requirements through reviews of comparable infrastructures across the UK, Europe and globally, community workshops and questionnaires, and direct engagement with potential beneficiaries from research, industry and government bodies. Significantly, the scoping study identified the importance of a digital infrastructure to enable a step-change in access to hydrological monitoring data. This would complement community access to the expected physical infrastructure for monitoring all phases of the water cycle across a range of catchment types.Key requirements for the proposed digital infrastructure, to be delivered through 2023-2028, include access to UK-wide hydrological data alongside new catchment observatory data, supporting field monitoring and innovation through open digital systems, advancing the state of the art for sensor data management, linking monitoring activities more closely with research data archives and delivering support for open science. The digital infrastructure would leverage technological developments e.g. in cloud-based virtual research environments, and be delivered alongside a significant community capacity building effort to support cultural change and enable researchers to transform ways-of-working to maximise its potential benefits.

The OZCAR (Critical Zone Observatories network) Research Infrastructure (RI) brings together several observatories documenting the critical zone, the thin pellicle on the Earth's surface between the non-weathered rocks and the lower atmosphere, which is the living environment of living beings. These long-term observatories were historically created in France to answer specific scientific questions such as the impact of rainfall acidification on forests, the genesis of extreme floods or the understanding of nitrate pollution. They monitor different compartments of the critical zone (atmosphere, soil, surface water, groundwater, cryosphere, wetlands, biosphere, etc.) through the measurement of a large number of meteorological, hydrological, hydrogeological, geochemical, surface fluxes and vegetation dynamics variables. The aims of OZCAR RI are: i) To foster data sharing with the scientific community through the development of a common data portal; ii) To promote the use of the collected data in models; ii) To allow the development and deployment of new measurement techniques, taking advantages of large projects funded by the French government such as the CRITEX project (Innovative equipment for the critical zone, 2011-2022) and the TERRA FORMA project (Designing and testing a smart observatory of socioecological systems in the Anthropocene, 2021-2029), that aim at deploying innovative measurements to document the critical zone and design new observatories in the Anthropocene; iv) To favor interdisciplinary researches through dedicated calls. The observatories, and their counterparts at the European scale gathered in eLTER RI, are highly instrumented sites where new measurement techniques can be tested and deployed, where hydrological functioning hypotheses can be assessed through the exploitation of data and models. These observatories are also good places to addressing some of the 23 unsolved problems in hydrology. The presentation will illustrate the value of a network of critical zone and hydrological observatories through examples of researches conducted in the OZCAR RI network. https://www.ozcar-ri.org/ https://www.critex.fr/critex-3/observatories/ https://terra-forma.cnrs.fr/ https://elter-projects.org/

The World Meteorological Organization (WMO) supports the National Meteorological and Hydrological Services in their mission to deliver operational hydrology services for achieving water security and the water-dependent/water-related Sustainable Development Goals. Operational hydrology is defined as “the real time and regular measurement, collection, processing, archiving and distribution of hydrological, hydrometeorological and cryospheric data, and the generation of analyses, models, forecasts and warnings which inform water resources management and support water-related decisions, across a spectrum of temporal and spatial scales”. The WMO ‘Vision and Strategy for Hydrology and its associated Plan of Action*’, approved by the Extraordinary Congress in October 2021, identifies eight long-term ambitions for operational hydrology in support of the global water agenda: (1) No one is surprised by a flood, (2) Everyone is prepared for drought, (3) Hydro-climate and meteorological data support the food security agenda, (4) High-quality data supports science, (5) Science provides a sound basis for operational hydrology, (6) We have a thorough knowledge of the water resources of our world, (7) Sustainable development is supported by hydrological information, and (8) Water quality is known. The WMO initiatives aim at improving operational hydrology applications by communicating the needs and benefits of hydrological research in support of operational hydrology, and enabling new research partnerships and collaborations with academia and practice communities. In this presentation, we focus on science priorities and knowledge gaps necessary to improve the delivery and the use of hydrologic data, information, and services in operational hydrology. We discuss the WMO Hydrological Research Strategy and how we can strengthen Hydrology/Water topics under the umbrella of the WMO Research Board. We will also report on the main achievements of an expert team, brought together at the end of 2021 to identify complementary and new research areas to strengthen the linkages between water, weather, climate and environment within the existing WMO related programmes, including the Global Atmosphere Watch (GAW) Programme, the World Climate Research Programme (WCRP), and the World Weather Research Programme (WWRP).* The process was led by the WMO Research Board (RB) with inputs from the WMO Hydrological Coordination Panel (HCP), the International Association of Hydrological Sciences (IAHS), and the Intergovernmental Hydrological Programme (UNESCO-IHP)

The eWaterCycle platform (https://www.ewatercycle.org/) is a fully Open Source and ‘FAIR by Design’ Platform where hydrologists can do computational hydrological research using their own, or other’s, models and data. Using eWaterCycle, computational hydrologist can focus on the hydrological part of their work, without the headache that often comes with the computational part.In eWaterCycle experiments are separated from models: experiments are build and run in Jupyter notebooks and models can be accessed as objects in these notebooks. The models themselves are ‘hidden’ in (Docker) containers and accessed through an easy interface. This interface and the technology behind it that we’ve build allows computational hydrologists to work with (each others) models written in different programming languages without having to access that code. Currently PCRGlobWB 2.0, Hype, LISFlood, WFLOW and MARMoT are among the models supported by eWaterCycle.Furthermore, pre-processing of atmospheric forcing data is handled transparently by ESMValTool, which separates the process of selecting and standardising variables from the steps needed to make forcing compatible with a specific model. If a source of forcing data has been made ready for one model in eWaterCycle it is easy to use it for any other. If a model has been used with one forcing data source, it is easy to swap it with another. Currently ERA5 and ERA-Interim are supported in eWaterCycle.With eWaterCycle use cases such as (but not limited to!) these are now easier to implement:Comparing two models for the same region against observation data (GRDC discharge observations are standard supported) to determine which model performs best for a given research question Coupling two models (in different programming languages) to exchange information at every timestep, for example making a Running a multi-model ensemble (including adding data assimilation of observations) Previously we have announced eWaterCycle as work in progress. At the 2022 General Assembly we will demonstrate the release of v1.0 of the eWaterCycle platform, giving the computational hydrological community access to a platform that supports fully reproducible, open, and FAIR Hydrological modelling.This work is currently under open review for publication in GMD: https://gmd.copernicus.org/preprints/gmd-2021-344/ and parts of this work have been presented at the AGU 2021 Fall Meeting.

Web-based distributed volunteer computing enables scientists to constitute platforms that can be used for computational tasks by using potentially millions of computers connected to the internet. It is a widely used approach for many scientific projects, including the analysis of radio signals for signs of extraterrestrial intelligence and determining the mechanisms of protein folding. User adoption and clients' dependence on the desktop software present challenges in volunteer computing projects. This study presents a web-based volunteer computing framework for hydrological applications that requires only a web browser to participate in distributed computing projects. The framework provides distribution and scaling capabilities for projects with user bases of thousands of volunteers. As a case study, we tested and evaluated the proposed framework with a large-scale hydrological flood forecasting model.

This presentation is going to address some of the main commonalities between hydrological research and hydrological practice, from the perspective of the Natural Catastrophe (Nat Cat) model developer. For example, hydrological research on the one hand, has a strong focus on the advancement of understanding hydrological processes. The hazard component of Nat Cat flood models, on the other hand, tends to be focused more on model suitability, accuracy and precision. However, it does rely heavily on a thorough understanding of the main hydro-meteorological drivers to describe catchment processes across the relevant spatial and temporal scales, and these are incorporated to achieve model realism and robustness, in particular when extrapolating outside the range of observed regimes. The latter is of importance when modelling extremes, which by definition are scarce.The presentation will also go into detail on the feedbacks between hydrological research and hydrological practice. For example, how the latest generation of Natural Catastrophe models benefit from the advances in hydrological research, e.g. research on large scale hydroclimatic patterns like ENSO, or climate change research. Incorporating the latest research in hydrological hazard modeling into Catastrophe Models ultimately improves the risk assessment for a set of assets. Also, large-scale flood risk models using coupled model chains that are relatively new in the hydrological research literature, have been part of the standard methodology for the Nat Cat models for a couple of decades, and might be seen as an indicator for the societal demand to perform novel research in these fields.

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Different means of hydrological data collection have developed and used. However, they are constraint in one way or other. This paper therefore revisited the rainfall simulator as potential tool for hydrological research. The research disclosed that there are three different types of rainfall simulators; drop former simulator, pressure nozzle simulator and hybrid simulator. It can further be classified as indoor model and outdoor. The research also showed that precipitation is the driving force in hydrological studies. Consequently, in the design of rainfall simulator, the following should be taken into consideration: nozzle spacing, pump size, nozzle size, nozzle type, nozzle spacing, plot size and pressure. Meanwhile, intensity, distribution uniformity, kinetic energy, rainfall drop size and rainfall terminal velocity should be noted in its evaluation. Factoring-in the aforementioned design considerations, data collection is made easy without necessarily waiting for the natural rainfall. Since the rainfall can be controlled, the erratic and unpredictable changeability of natural rainfall is eliminated. Emanating from the findings, pressurized rainfall simulator produces rainfall characteristics similar to natural rainfall, which is therefore recommended for laboratory use if natural rainfall-like characteristics is the main target.

The acceleration of climate change and its impact highlight the need for long-term reliable climate data at high spatiotemporal resolution to answer key science questions in cold regions hydrology. Prior to the digital age, climate records were archived on paper. For example, from the 1950s to the 1990s, solar radiation data from recording stations worldwide were published in booklets by the former Union of Soviet Socialist Republics (USSR) Hydrometeorological Service. As a result, the data are not easily accessible by most researchers. The overarching aim of this research is to develop techniques to convert paper-based climate records into a machine-readable format to support environmental research in cold regions. This study compares the performance of a proprietary optical character recognition (OCR) service with an open-source OCR tool for digitizing hydrometeorological data. We built a digitization pipeline combining different image preprocessing techniques, semantic segmentation, and an open-source OCR engine for extracting data and metadata recorded in the scanned documents. Each page contains blocks of text with station names and tables containing the climate data. The process begins with image preprocessing to reduce noise and to improve quality before the page content is segmented to detect tables and finally run through an OCR engine for text extraction. We outline the digitization process and report on initial results, including different segmentation approaches, preprocessing image algorithms, and OCR techniques to ensure accurate extraction and organization of relevant metadata from thousands of scanned climate records. We evaluated the performance of Tesseract OCR and ABBYY FineReader on text extraction. We find that although ABBY FineReader has better accuracy on the sample data, our custom extraction pipeline using Tesseract is efficient and scalable because it is flexible and allows for more customization.

Openly accessible global scale surface water chemistry datasets are urgently needed to detect widespread trends and problems, to help identify their possible solutions, and identify critical spatial data gaps where more monitoring is required. Existing datasets are limited in availability, sample size/sampling frequency, and geographic scope. These limitations inhibit the answering of emerging transboundary water chemistry questions, for example, the detection and understanding of delayed recovery from freshwater acidification. Here, we begin to address these limitations by compiling the global surface water chemistry (SWatCh) database, available on Zenodo (DOI: https://doi.org/10.5281/zenodo.4559696) We collect, clean, standardize, and aggregate open access data provided by six national and international agencies to compile a database consisting of three relational datasets: sites, methods, and samples, and one GIS shapefile of site locations. We remove poor quality data (for example, values flagged as suspect), standardize variable naming conventions and units, and perform other data cleaning steps required for statistical analysis. The database contains water chemistry data across seven continents, 17 variables, 38,598 sites, and over 9 million samples collected between 1960 and 2019. We identify critical spatial data gaps in the equatorial and arid climate regions, highlighting the need for more data collection and sharing initiatives in these areas, especially considering freshwater ecosystems in these environs are predicted to be among the most heavily impacted by climate change. We identify the main challenges associated with compiling global databases – limited data availability, dissimilar sample collection and analysis methodology, and reporting ambiguity – and provide recommendations to address them. By addressing these challenges and consolidating data from various sources into one standardized, openly available, high quality, and trans-boundary database, SWatCh allows users to conduct powerful and robust statistical analyses of global surface water chemistry.

There is increasing recognition of the need to incorporate the complex and dynamic interactions between society and water in studies of water resource systems. The study of human-water dynamics requires the involvement of researchers from different disciplines, including hydrology and social science. This paper tracks recent trends in socio-hydrological research using quantitative and qualitative methods. Bibliographic metrics and network analysis are used to identify general trends and illustrate the internal connections in this small but growing interdisciplinary field. Results show that hydrologists dominate research in socio-hydrology as presently defined, with far less participation from social scientists. Research questions for socio-hydrology tend to focus on system dynamics and are often not framed in a way that engages the interests and expertise of social scientists. A qualitative analysis addresses key barriers to the interdisciplinary development of socio-hydrology and identifies research needs and directions for better integration of the human dimensions of water science. Attracting social scientists to this field requires a broader conceptualization of socio-hydrology to focus on sustainable development, risk assessment, hazard management, resilience, adaptation, and knowledge mobilization in addition to hydrology’s traditional focus on systems modeling and decision support. We propose three themes for thematic focus: systemic risk and natural hazards; sustainability science; and adaptive governance. This broader framing of socio-hydrology is inherently more interdisciplinary, brings new methods and viewpoints to the field, and ensures that place-based local values are included in studies of water system dynamics.

The emergence of high-resolution observational tools, information and communication technologies, cloud computing and big data are disrupting the water sector in an unprecedented way. In the field of hydrological sciences, research calls aimed at observing, backcasting and forecasting terrestrial water resources at finer space-time resolutions have been made over the past years by the scientific community. Here, we introduce the Hydrological Observatory of Mexico City (OH-IIUNAM), an academic initiative consisting of a dense network of 55 state-of-the-art precipitation sensors (optical disdrometers and weighing rain gauges) located within Mexico City, one of the largest urban centers of the world. The objective of OH-IIUNAM, given its open-data philosophy, is to enable scientific research within urban environments by providing a real-time hydro-meteorological observational platform at the hyper-resolution (dt=1 minute). Potential niches of opportunity ranging from atmospheric processes to hydrological modeling and design in urban areas are envisaged and discussed. Future expansion phases of OH-IIUNAM are expected to incorporate streamflow, groundwater and water quality.HTML aquí.

Global Satellite Mapping of Precipitation (GSMaP), Climate Hazards Group InfraRed Preconception with Station data (CHIRPS), Tropical Rain Measurement Mission Multisatellite Precipitation Analysis (TRMM 3B42 V7) and Rainfall Estimation from Soil Moisture Observations (SM2RAIN) are satellite precipitation products with high applicability, but their applicability in hydrological research in arid mountainous areas is not clear. Based on precipitation and runoff data, this study evaluated the applicability of each product to hydrological research in a typical mountainous basin (the Qaraqash River basin) in an arid region by using two methods: a statistical index and a hydrological model (Soil and Water Assessment Tool, SWAT). Simulation results were evaluated by Nash efficiency coefficient (NS), relative error (PBIAS) and determination coefficient (R2). The results show that: (1) The spatial distributions of precipitation estimated by these four products in the Qaraqash River basin are significantly different, and the multi-year average annual precipitation of GSMaP is 97.11 mm, which is the closest to the weather station interpolation results. (2) On the annual and monthly scales, GSMaP has the highest correlation (R ≥ 0.82) with the observed precipitation and the smallest relative error (BIAS < 6%). On the seasonal scale, the inversion accuracy of GSMaP in spring, summer and autumn is significantly higher than other products. In winter, all four sets of products perform poorly in estimating the actual precipitation. (3) Monthly runoff simulations based on SM2RAIN and GSMaP show good fitting (R2 > 0.6). In daily runoff simulation, GSMaP has the greatest ability to reproduce runoff changes. The study provides a reference for the optimization of precipitation image data and hydrological simulation in data-scarce areas.

The present paper represents the complex monitoring results of the hydrological field condition and water dynamics in the Black Sea northern part within the economic region of Russia carried out in the scientific expeditions in 2016 (87th, 89th and 91st cruises of R/V Professor Vodyanitsky). It is shown that distributions of all the thermohaline characteristics obtained from the data of three surveys demonstrate a pronounced seasonal character of a signal. It is manifested in consistent decrease of the upper mixed layer mean temperature, growth of temperature in the cold intermediate layer core and in deepening of the lower boundary of the upper mixed layer, the cold intermediate layer core and the hydrogen sulphide zone upper boundary. In course of three surveys, the Rim Current deep stream was located above the continental slope. The maximum velocities are observed nearby the Crimea southwestern coast. In the western part of the region considered, a well pronounced Sevastopol anticyclone (most distinct in October, 2016) is observed. The Sevastopol anticyclone manifests itself also in distributions of the hydrological characteristics. Temperature increase, salinity decrease and deepening of the lower boundary of the upper mixed layer and the cold intermediate layer core are observed on the sea surface in the anticyclone area.

The National Institute of Hydrology (NIH) is a premier research Institute in India in the area of hydrology and water resources. The Institute was established in 1978 with the main objective of undertaking, aiding, promoting and coordinating systematic and scientific work in all aspects of hydrology. The Institute has its headquarters at Roorkee (Uttarakhand), four regional centres at Belagavi, Jammu, Kakinada and Bhopal and two centres for flood management studies at Guwahati and Patna. The Institute is well equipped to carry out computer, laboratory and field oriented studies. This article presents an overview of research activities being undertaken by the Institute.

Women play a central part in the provision, management and safeguarding of water. This pivotal role of women as providers and users of water and guardians of the living environment has seldom been reflected in institutional arrangements for the development and management of water resources. Acceptance and implementation of this principle requires positive policies to address women's specific needs and to equip and empower women to participate at all levels in water resources programmes, including decision-making and implementation. The objective of this paper is to highlight some of the recent contribution of women in the field of Hydrology.

This paper deals with hydrological research in regard to the water resources crisis in the vulnerable areas found in the northern part of China. This area includes three main river basins, namely the basins of the Yellow (Huang) River, the Hai River and the Huai River. Several water problems are becoming very severe. Among them, two are the most critical: the Yellow River has been drained dry in the main course of its lower reaches and along its major tributaries, and the groundwater table has rapidly declined in the floodplains of the three rivers' downstream areas. To counter the problems, particularly the critical issues mentioned above, hydrological research, which serves as the basis of water development and management, has been carried out in the last two decades. This paper addresses three basic scientific problems in North China, namely: (a) water consumption and the capacity for saving water; (b) the changes in hydrological processes and water resources caused by natural change and human activities; and (c) the ability to supply water resources and water safety in terms of both quantity and quality within a changing environment. However, opportunities and challenges for ameliorating the problems exist, and new ideas and methodology to solve the problems have been proposed, such as the interface process study on the interactions in the soil-root interface, the plant-atmosphere interface, the soil-atmosphere interface, and the interface of soil water and groundwater. In order to manage water resources in a sustainable manner, the study of water resources' renewal ability as affected by natural change and human activity is addressed from the viewpoint of both water quantity and quality, and their integration. To reduce the vulnerability of water resources in regional water management, a paradigm of sustainable water resources utilization is also proposed, using water-heat balance, water-salt balance, water-sediment balance, and water supply-demand balance. This approach may help reveal the basic problems and point to possible approaches to solving the water problems in North China in the 21st century. Copyright (C) 2004 John Wiley Sons

The use of electrical resistivity tomography (ERT; non-intrusive geophysical technique) was assessed to identify the hydrogeological conditions at a surface water/groundwater test site in the southern Black Forest, Germany. A total of 111 ERT transects were measured, which adopted electrode spacings from 0·5 to 5 m as well as using either Wenner or dipole-dipole electrode arrays. The resulting two-dimensional (2D) electrical resistivity distributions are related to the structure and water content of the subsurface. The images were interpreted with respect to previous classical hillslope hydrological investigations within the same research basin using both tracer methods and groundwater level observations. A raster-grid survey provided a quasi 3D resistivity pattern of the floodplain. Strong structural heterogeneity of the subsurface could be demonstrated, and (non)connectivities between surface and subsurface bodies were mapped. Through the spatial identification of likely flow pathways and source areas of runoff, the deep groundwater within the steeper valley slope seems to be much more connected to runoff generation processes within the valley floodplain than commonly credited in such environmental circumstances. Further, there appears to be no direct link between subsurface water-bodies adjacent to the stream channel. Deep groundwater sources are also able to contribute towards streamflow from exfiltration at the edge of the floodplain as well as through the saturated areas overlying the floodplain itself. Such exfiltrated water then moves towards the stream as channelized surface flow. These findings support previous tracer investigations which showed that groundwater largely dominates the storm hydrograph of the stream, but the source areas of this component were unclear without geophysical measurements. The work highlighted the importance of using information from previous, complementary hydrochemical and hydrometric research campaigns to better interpret the ERT measurements. On the other hand, the ERT can provide a better spatial understanding of existing hydrochemical and hydrometric data. Copyright © 2009 John Wiley & Sons, Ltd.

We want to develop a dialogue between geophysicists and hydrologists interested in synergistically advancing process based watershed research. We identify recent advances in geophysical instrumentation, and provide a vision for the use of electrical and magnetic geophysical instrumentation in watershed scale hydrology. The focus of the paper is to identify instrumentation that could significantly advance this vision for geophysics and hydrology during the next 3–5 years. We acknowledge that this is one of a number of possible ways forward and seek only to offer a relatively narrow and achievable vision. The vision focuses on the measurement of geological structure and identification of flow paths using electrical and magnetic methods. The paper identifies instruments, provides examples of their use, and describes how synergy between measurement and modelling could be achieved. Of specific interest are the airborne systems that can cover large areas and are appropriate for watershed studies. Although airborne geophysics has been around for some time, only in the last few years have systems designed exclusively for hydrological applications begun to emerge. These systems, such as airborne electromagnetic (EM) and transient electromagnetic (TEM), could revolutionize hydrogeological interpretations. Our vision centers on developing nested and cross scale electrical and magnetic measurements that can be used to construct a three-dimensional (3D) electrical or magnetic model of the subsurface in watersheds. The methodological framework assumes a ‘top down’ approach using airborne methods to identify the large scale, dominant architecture of the subsurface. We recognize that the integration of geophysical measurement methods, and data, into watershed process characterization and modelling can only be achieved through dialogue. Especially, through the development of partnerships between geophysicists and hydrologists, partnerships that explore how the application of geophysics can answer critical hydrological science questions, and conversely provide an understanding of the limitations of geophysical measurements and interpretation. Copyright © 2008 John Wiley & Sons, Ltd.

The International Conference on Hydrological Research Basins and the Environment, was held at Wageningen from September 24th to 28th. The conference was organized by the Committee of the European Network of Experimental and Representative Basins and the National Committee of the Netherlands for the International Hydrological Programme of Unesco. Much of our basic knowledge on hydrological processes has come from studies in research basins. These well-instrumented basins have also produced much very suitable data for hydrological investigations an water resources management studies. In recent years the significance of the role of research basins in hydrology has considerably changed. It was found that research basins also constitute an irreplaceable tool for studying anthropogenic effects on water resources and the environment. Detailed observations and measurements have strongly increased the awareness of the effect of human activities on the quality of the environment and consequently the threat to life. Studying the changes caused by anthropogenic effects is most useful when carried out in well-equipped research basins, supported by basin experiments. Such studies are also a valuable starting point for sound future environmental management. The main objective of the conference was to bring together scientists involved in hydrological basin research, to stimulate the exchange of information and to encourage international cooperation in research projects. During the conference the Third General Meeting of the European Network of Experimental and Representative Basins was held. This network of basins, covering nine countries in Europe, organizes periodical meetings and tries to enhance harmonization of observations and methods of analysis, and to implement research projects of common interest.

The International Conference on Hydrological Research Basins and the Environment, was held at Wageningen from September 24th to 28th. The conference was organized by the Committee of the European Network of Experimental and Representative Basins and the National Committee of the Netherlands for the International Hydrological Programme of Unesco. Much of our basic knowledge on hydrological processes has come from studies in research basins. These well-instrumented basins have also produced much very suitable data for hydrological investigations an water resources management studies. In recent years the significance of the role of research basins in hydrology has considerably changed. It was found that research basins also constitute an irreplaceable tool for studying anthropogenic effects on water resources and the environment. Detailed observations and measurements have strongly increased the awareness of the effect of human activities on the quality of the environment and consequently the threat to life. Studying the changes caused by anthropogenic effects is most useful when carried out in well-equipped research basins, supported by basin experiments. Such studies are also a valuable starting point for sound future environmental management. The main objective of the conference was to bring together scientists involved in hydrological basin research, to stimulate the exchange of information and to encourage international cooperation in research projects. During the conference the Third General Meeting of the European Network of Experimental and Representative Basins was held. This network of basins, covering nine countries in Europe, organizes periodical meetings and tries to enhance harmonization of observations and methods of analysis, and to implement research projects of common interest.

The International Conference on Hydrological Research Basins and the Environment, was held at Wageningen from September 24th to 28th. The conference was organized by the Committee of the European Network of Experimental and Representative Basins and the National Committee of the Netherlands for the International Hydrological Programme of Unesco. Much of our basic knowledge on hydrological processes has come from studies in research basins. These well-instrumented basins have also produced much very suitable data for hydrological investigations an water resources management studies. In recent years the significance of the role of research basins in hydrology has considerably changed. It was found that research basins also constitute an irreplaceable tool for studying anthropogenic effects on water resources and the environment. Detailed observations and measurements have strongly increased the awareness of the effect of human activities on the quality of the environment and consequently the threat to life. Studying the changes caused by anthropogenic effects is most useful when carried out in well-equipped research basins, supported by basin experiments. Such studies are also a valuable starting point for sound future environmental management. The main objective of the conference was to bring together scientists involved in hydrological basin research, to stimulate the exchange of information and to encourage international cooperation in research projects. During the conference the Third General Meeting of the European Network of Experimental and Representative Basins was held. This network of basins, covering nine countries in Europe, organizes periodical meetings and tries to enhance harmonization of observations and methods of analysis, and to implement research projects of common interest.

is the combined outcome of both the 2001 EGS ses-sion on the ‘Water balance of mountain basins’ in Nice and the 2002 Annual Meeting of the Ger-man Hydrological Working Group in Berlin. A variety of hydrological and meteorological research top-ics presented at these meetings focused on water resources, modelling, parameterization, remote sens-ing, snow and ice melt, evaporation and transpiration. Case studies concentrated especially on moun-tain areas, which ranged in altitude from 1500 to 6000 m, and on a variety of regions, such asthe Himalayas, Karakorum, Hindukush, Yemen Mountain Massif, Norwegian Scandes and Alps. Theanalysis of water balance components was conducted at many different temporal and spatial scales,ranging from annual and seasonal to daily and hourly, and from entire basins to single lysimetricanalyses.The current discussion about climatic–hydrologic change and bio-adaptability reflects the necessityfor more comprehensive and more detailed knowledge about water balance in mountain basins. Sincemountain watersheds are source areas for large rivers, an understanding of the water balance is invalu-able. This should include a variety of components, such as water input, water storage, water loss, andwater transfer potentials on steep, heterogeneous surfaces. Many of the associated processes are insuf-ficiently investigated, although they are of major significance for both hydrologists and water resourcemanagers.AIMIt is the aim of this special issue to present a diverse range of topics and research areas in order to revealthe wide spectrum of research topics and methods on water balance studies in mountain basins. These stud-ies demonstrate both the success and the emerging difficulties and shortcomings in different research fields.Examples from the developed and from the developing world not only promote comparisons, but also newideas about the availability and transferability of methods.

Physical geographers are often confronted with the decision of whether to publish in geography or nongeography journals. The present study seeks to quantify the number of articles with a significant hydrology content published in geography versus hydrology journals by physical geographers from 1997 to 2002 using the ISI Web of Knowledge electronic database. Of 690 articles published in the 10 selected geography and hydrology journals during the period of study, over four-fifths were published in hydrology journals. Based on our interpretation of the data, the comparatively smaller audience in geography and the risk of acquiring fewer citations compels physical geographers to publish in hydrology journals for increased visibility. A critical mass of physical geographers should consider publishing some of their work in physical geography journals to elevate the status of geography in the academy.

This paper reports some of the achievements in hydrological research associated with the Mackenzie GEWEX Study (MAGS). MAGS is a multifaceted study of the energy and water cycle in the Mackenzie River Basin, north-western Canada, and emphasizes cold-region processes and modelling. It pursues methodologies of scaling-up process studies to a large river basin that has few measurement sites. This methodology involves new developments, adapting mid-latitude algorithms to the high latitude setting and promoting the use of remote sensing tools for scaling-up. Intensive hydrological process studies have been concentrated at a number of sites. These have been chosen to represent different biophysical facets of the Mackenzie River Basin. They include northern basins in open tundra and at tree-line, a western basin representing the hilly and mountainous western side of the basin, central basin sites of wetlands, Precambrian Shield terrain and the Mackenzie Basin counterpart of the large Laurentian Great Lakes. The most southerly site represents a mixed-wood boreal forest site that is undergoing land-use change as a result of forest harvesting. Regional community model analysis indicates that processes of lee cyclogenesis result in differential input of precipitation across the basin. Significant results centre on models of snow accumulation featuring the role of blowing snow, intercepted snow and snowmelt. These models emphasize the importance of snow patchiness to speed of melt. Snowmelt infiltration into frozen soils is important in controlling runoff, and tundra microlandforms play a unique role in determining the surface runoff characteristics. On the western margins of the basin, there is a very significant difference in the hydrological behaviour of slopes of different aspects as a result of differences in permafrost and vegetation. In the central basin, a deeper understanding of components of the water budget is being gained through stable isotope analysis of wetland waters.

Mountains are fragile ecosystems and globally important as water towers of the earth. Sustainable use of mountains depends upon conservation and optimal use of soil and water resources (Ives & Messerli 1989). Despite regional and global efforts to understand the hydrology of the Himalayan region, soil and water conservation (SWC) programmes in this region mainly rely upon engineering measures. For want of cost-effective vegetative (bioengineering) measures (Deoja et al. 1991), and land use and land cover conducive to SWC, the fragile Himalayan watersheds continue to lose soil and water at alarming rates.