Sharing of open government data is amongst other reasons hindered by incompatibility of data models in different data collections. Only a few areas in the environmental domain have progressed towards commonly used data models. The purpose of this paper is to share with the community a data model which is used in a spatial information platform being built for the purpose of sharing open government data in the domain of water sciences. The objective when building the information model was not to be restricted to one and only one (meta)data standard. The information model therefore uses several standards and extension mechanisms: the ISO19000 series, the Comprehensive Knowledge Archive Network (CKAN), dynamic tag extension and dynamic content extension. The CKAN domain model can also be mapped to semantic-web-compatible standards like Dublin Core and the Data Catalogue Vocabulary of the World Wide Web Consortium.