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2 GWML2-Constituent: the biologic, chemical, and material elements of a fluid body.
3 GWML2-Flow: groundwater flow within and between containers. 4 GWML2-Well: water wells, springs, and monitoring sites.
5 GWML2-WellConstruction: the components used to construct a well. 6 GWML2-AquiferTest: the elements composing an aquifer test e.g. pumping test.
Altogether, the schemas and packages represent a precise description of the key features associated with the groundwater domain, as well as their properties and relationships.
This provides a semantics and syntax for the correct machine interpretation of the data, which promotes proper use of the data in further analysis. Existing systems can use
GWML2 to ‘bridge’ between existing schema or systems, allowing consistency of the data to be maintained and enabling interoperability.
1.1 Motivation
A significant portion of the global water supply can be attributed to groundwater resources. Effective management of such resources requires the collection, management
and delivery of related data, but these are impeded by issues related to data availability, distribution, fragmentation, and heterogeneity: collected data are not all readily available
and accessible, available data is distributed across many agencies in different sectors, often thematically fragmented, and similar types of data are diversely structured by the
various data providers. This situation holds both within and between political entities, such as countries or states, thereby impairing groundwater management across all
jurisdictions. Groundwater data networks are an emerging solution to this problem as they couple data providers through a unified data delivery vehicle, thus reducing or
eliminating distribution, fragmentation, and heterogeneity through the incorporation of standards for data access and data content. The relative maturity of OGC data access
standards, such as the Web Feature Service WFS and Sensor Observation Service SOS, combined with the rise of water data networks, have created a need for
GroundWaterML2 GWML2, a common groundwater data specification.
1.2 Historical background
Several activities have influenced the development of GWML2: GWML1: a GML application schema for groundwater data developed at Natural
Resources Canada used to exchange groundwater data within Canada, between Canada and the USA, and in some other international initiatives Boisvert
Brodaric, 2012. GWIE1: an interoperability experiment within the OGC HDWG, in which
groundwater data was shared across the USA-Canada border Brodaric Booth, 2011.
INSPIRE Data Specification on Geology: a conceptual model for geology and hydrogeology with regulatory force in the European Union INSPIRE, 2013, and
for which GWML2 is expected to be an encoding candidate.
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2. Conformance
This specification has been written to be compliant with the OGC Specification Model – A Standard for Modular Specification OGC 08-131r3. Extensions of this specification
shall themselves be conformant to the OGC Specification Model.
2.1 XML implementation
The XML implementation encoding of the conceptual and logical groundwater schemas is described using the XML Schema language and Schematron.
Requirements for one standardization target type are considered: - data instances
i.e. XML documents that encode groundwater data. As data producing applications should generate conformant data instances, the requirements and tests described in this
specification effectively also apply to that target.
Conformance with this specification shall be checked using all the relevant tests specified in Annex A normative of this document. The framework, concepts, and methodology
for testing, and the criteria to be achieved to claim conformance are specified in ISO 19105: Geographic information — Conformance and Testing. In order to conform to this
OGC™
encoding specification, a standardization target shall implement the core conformance class, and choose to implement any one of the other conformance classes
i.e. extensions. All requirements-classes and conformance-classes described in this document are owned
by the standards identified.
2.2 Use of vocabularies
