Hydroseek is an ontology-aided search engine for finding scientific data on water quality and hydrology from approximately 1.9 million sites in the USA. Hydroseek creates a unified view over databases of agencies such us US Geological Survey, Environmental Protection Agency, Texas Commission of Environmental Quality, Chesapeake Information Management System, National Atmospheric Deposition Program, Long Term Ecological Research Network and individual researchers removing the semantic, syntactic and information system heterogeneity barriers to improve the search experience and reduce time spent on data discovery and preparation prior to processing. Depending on the method of interaction (GUI or web services) and the function invoked output can be provided using CUAHSI WaterML, GML Features or Microsoft Excel.

System uses Microsoft Virtual Earth map interface with OWL ontologies providing the knowledge base used in supplying the auto-complete keywords and classifying of search results.

Hydroseek follows Services Oriented Architecture (SOA) and most functionalities are available via SOAP webservices. System also supports queries using NASA's Global Change Master Directory (GCMD) keywords via webservices.