Version 1.0 of WaterML was published in 2009 by the Consortium of Universities for the Advancement of Hydrologic Science.[3] WaterML 1.0 (and 1.1) is an XML exchange format developed for use specifically in the United States.
WaterML 2.0
WaterML 2.0 is an open standard[2] of the OGC. Version 2.0 marks a harmonisation with different formats from various organisations and countries, including the Australian Water Data Transfer Format, WaterML 1.0 from the United States,[3]XHydro from Germany, and with existing OGC formats. WaterML 2.0 was adopted as an official standard by the OGC in September 2012,[4][5] endorsed by the US Federal Geographic Data Committee,[6] and has been proposed for adoption by the World Meteorological Organisation (WMO).[7]
Example uses include: exchange of data for operational hydrological monitoring programs; supporting operation of infrastructure (e.g. dams, supply systems); cross-border exchange of observational data; release of data for public dissemination; enhancing disaster management through data exchange; and exchange in support of national reporting. The standard was developed through a harmonisation process[8] by members of the joint OGC-WMO Hydrology Domain Working Group.[9]
Structure
WaterML 2.0 makes use of existing OGC standards, primarily Observations and Measurements (O&M) and the Geography Markup Language (GML). This enhances consistency and interoperability with other standards and web services. Through use of the O&M standard, WaterML 2.0 defines types allowing for standard definition of the core properties relating to hydrological time series, including:
The observed phenomenon
Spatial context
Temporal bounds
Procedure used in generating the time series (e.g. raw data from a sensor)
Result-specific metadata, such as time series qualifiers, interpolation types, comments, quality codes etc.
Monitoring points
Collections of related objects
Vocabularies for domain-specific terms
The core information model is defined using the Unified Modelling Language, allowing for flexibility in creating implementation-specific encodings. The standard defines a GML-conformant XML encoding allowing for use with OGC Web Services.
^[4], WMO, Resolution 3, Commission for Hydrology session November 2012 - Abridged final report with resolutions and recommendations
^[5], Taylor, P.; Cox, S.; Walker, G.; Valentine, D; Sheahan, P. WaterML 2.0: Development of an open standard for hydrological time series data exchange. Journal of Hydroinformatics. doi:10.2166/hydro.2013.174.
^[6] WMO/OGC Hydrology Domain Working Group wiki page
