International Standardization Of Water Information Exchange: Activities Of The WMO/OGC Hydrology Domain Working Group

Hydrologic information is generated and published by many government, research, commercial and citizen groups around the world. The formats and protocols used to share the data are heterogeneous, with little agreement about semantics of hydrologic measurements, description of hydrologic features, or metadata content. A broad consensus on hydrologic data sharing formats is needed to ensure that the information can be reliably discovered, interpreted, accessed and integrated. This has been the focus of the Hydrology Domain Working Group (Hydro DWG), established in 2009 as a joint working group of the World Meteorological Organisation (WMO) and the Open Geospatial Consortium (OGC). It consists of members from government, research and the commercial sectors and it plays an important role by bringing together organisations to agree on ways to improve our ability to share water information. In Sept. 2012 the OGC adopted ”WaterML2.0 Part 1: Time series” as an OGC Standard. At its 14th Session in Nov. 2012 the WMO Commission for Hydrology adopted a resolution that starts a process to register this standard as a joint WMO/ISO standard. WaterML2.0 is the first international standard for encoding water observation time series, developed by the Hydro DWG and the WaterML2.0 Standards Working Group after several years of specification work and interoperability experiments. Built on widely used OGC and ISO standards, it represents a breakthrough for linking local to global water information sources into large water information networks and enabling efficient analysis and modelling of water data across information sources. WaterML2.0 Part 1 is the first in a series of planned enhancements and extensions. Current work involves standardised communication of descriptions of surface and groundwater features, ratings and gaugings, river cross sections and water quality. It also contributed to the development of a hydrology domain feature model and hydrology vocabularies, which are essential for interoperability

Interoperability Between GRDC\u27s Data Holding And The GEOSS Infrastructure

The Global Runoff Data Centre (GRDC) operates under the auspices of the World Meteorological Organization as an international data centre for hydrological data and information on a global scale. Its primary objective is to support the water and climate related programmes and projects of the United Nations, its specialised agencies, and the scientific research community on global and climate change and integrated water resources management. The Global Runoff Database maintained by the GRDC is a valuable data resource and a subset of its data is contributed to the Global Earth Observation System of Systems’ (GEOSS) freely accessible Data Core. As a partner in the project GEOSS Interoperability for Weather, Ocean and Water (GEOWOW) the GRDC supports the evolving GEOSS in terms of interoperability, standardization and functionality. In the framework of GEOWOW a profile of the OGC Sensor Observation Service Interface Standard 2.0 (SOS) is being developed. This SOS Profile for the Hydrology Domain specifies extensions to the service interface and uses the OGC WaterML 2.0 standard for encoding hydrological time series data. Moreover, technical partners of the GEOWOW project facilitate software implementations of the standardization advancements. Deploying and incorporating these into GRDC’s data holding infrastructure allows for a seamless integration of GRDC’s data provision capabilities into GEOSS. Furthermore, client web applications to visualize time series data provided via an OGC Web Service infrastructure makes it possible to offer additional benefit and allows for accessing and assessing data more easily

Reference hydrologic networks I: the status and potential future directions of national reference hydrologic networks for detecting trends

Identifying climate-driven trends in river flows on a global basis is hampered by a lack of long, quality time series data for rivers with relatively undisturbed regimes. This is a global problem compounded by the lack of support for essential long-term monitoring. Experience demonstrates that, with clear strategic objectives, and the support of sponsoring organizations, reference hydrologic networks can constitute an exceptionally valuable data source to effectively identify, quantify and interpret hydrological change—the speed and magnitude of which is expected to a be a primary driver of water management and flood alleviation strategies through the future—and for additional applications. Reference hydrologic networks have been developed in many countries in the past few decades. These collections of streamflow gauging stations, that are maintained and operated with the intention of observing how the hydrology of watersheds responds to variations in climate, are described. The status of networks under development is summarized. We suggest a plan of actions to make more effective use of this collection of networks

Small hydrological research basins in Germany

Small research basins are hotspots of hydrological research. They are extensively equipped to measure different hydrological parameters with high temporal and spatial resolution. The resulting data are the basis for the identification of regional basin characteristics and hydrological processes, statistical analyses, model development and parameter identification. Altogether these comprehensive research activities address a wide range of objectives and goals, such as analyses of initial landscape genesis, water and nutrient balance, or current climate projections on runoff patterns. The German IHP/HWRP working group "FRIEND/ERB" supports such research activities in small hydrological basins in Germany and contributes to UNESCO’s International Hydrological Program (IHP) as well as the Hydrology and Water Resources Program (HWRP) of WMO. Its focus is on catchments smaller than 50km²with continuous data acquisition of time series longer than 5 years. They are operated by universities, environmental authorities and other research institutions. This presentation illuminates the German research in selected small hydrological research basins ranging in size from 0.06 km² to 50 km². It summarizes the objectives, measured variables and chosen methodical aspects. Continuous measurements at the respective gauges will in future be more and more supplemented by spatially and temporally higher resolution measurement campaigns. The advancement of sensor and IT technologies promotes a continuous increase in data volumes, allowing for more precise and specific analyses and predictions as well as the possibility of a better understanding of the prevailing hydrological processes including their spatio-temporal variability. But often this requires the development of new evaluation methods. The use of models supports these goals. Scenarios allow the evaluation of different land use and management strategies and of possible impacts caused by climate change.The evaluation of the German IHP/HWRP working group "FRIEND/ERB" emphasises an increasing need for high resolution measurements and long time series as well as regular updates of all research activities in small hydrological basins. Only their continuation will also in future provide valuable contributions to research, teaching and the management of environmental problems. Their integration into a research network increases the efficiency of the activities and provides opportunities for joint evaluations

GRDC-Caravan: extending the original dataset with data from the Global Runoff Data Centre

<p>Large-sample datasets are essential in hydrological science to support modelling studies and global assessments. This dataset is an extension to <em>Caravan</em>, a global community dataset of meteorological forcing data, catchment attributes, and discharge data for catchments around the world (Kratzert et al. 2023<sup>1</sup>).</p> <p>The extension includes a subset of those hydrological discharge data and station-based watersheds from the Global Runoff Data Centre (GRDC), which are covered by an open data policy (Attribution 4.0 International; CC BY 4.0). In total, the dataset covers stations from 5357 catchments and 25 countries worldwide with a time series record from 1950 – 2023.</p> <p>GRDC is an international data centre operating under the auspices of the World Meteorological Organization (WMO) at the German Federal Institute of Hydrology (BfG). Established in 1988, it holds the most substantive collection of quality assured river discharge data worldwide. Primary providers of river discharge data and associated metadata are the National Hydrological and Hydro-Meteorological Services of WMO Member States.</p> <p><sup>1</sup>Kratzert, F., Nearing, G., Addor, N. et al. Caravan - A global community dataset for large-sample hydrology. Sci Data 10, 61 (2023). <a href="https://doi.org/10.1038/s41597-023-01975-w">https://doi.org/10.1038/s41597-023-01975-w</a></p> <p> </p&gt

A review of the status, research opportunities and future of large-scale river flow archives

Large-scale river flow archives hold vital data to identify and understand the changing water cycle, to underpin modelling of future regional and global hydrology, and to inform water resource assessment and decision making. Notable examples of such datasets include that held by the WMO Global Runoff Data Centre (GRDC) and the UNESCO-FRIEND European Water Archive (EWA). For large-scale river flow archives to be useful research resources, they must be fit-for-purpose. However, such datasets are under threat by shrinking gauging network coverage and more restricted access to national-scale information. This article aims: (a) to highlight the value of these databases for study of important blue-skies and applied issues; (b) to present a stateof- the-art review of large-scale river flow datasets; and (c) to propose ways to consolidate historical, and secure future, data. We seek to stimulate debate on this topic and action to move forwar