WaterML is a technical standard and information model used to represent hydrological time series structures.
The standard was developed through a harmonisation process[8] by members of the joint OGC-WMO Hydrology Domain Working Group.
[9] WaterML 2.0 makes use of existing OGC standards, primarily Observations and Measurements (O&M) and the Geography Markup Language (GML).
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 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.