Development of a Community Hydrologic Information System

David G. Tarboton, Utah State University
J. S. Horsburgh
D. R. Maidment
T. Whiteaker
I. Zaslavsky
M. Piasecki
J. Goodall
D. Valentine
T. Whitenack


Over the next decade, it is likely that science and engineering research will produce more scientific data than has been created over the whole of human history. The successful use of these data to achieve new scientific breakthroughs will depend on the ability to access, integrate, and analyze these large datasets. The way these data are organized and manipulated either enables or inhibits the analyses that can be performed. The Consortium of Universities for the Advancement of Hydrologic Science, Inc (CUAHSI) is developing information technology infrastructure to support advanced hydrologic analysis and education. The CUAHSI Hydrologic Information System (HIS) is an internet based system to support the sharing of hydrologic data. It is comprised of hydrologic databases and servers connected through web services as well as software for data publication, discovery and access. The HIS is founded upon an information model for observations at stationary points that supports its data services. The CUAHSI Observations Data Model (ODM) provides community defined semantics needed to allow sharing of hydrologic information. Following this uniform semantic model, CUAHSI HIS web services provide access to multiple disparate data sources: from national repositories such as the USGS National Water Information System (NWIS) and USEPA Storage and Retrieval System (STORET), to distributed databases published by academic researchers and community groups on their own servers in a standard format. These web services are registered to a central HIS website, where they become searchable and accessible through centralized discovery and data access tools. HIS utilizes both an XML and relational database schema for transmission and storage of data respectively. WaterML (Water Markup Language) is the XML schema used for data transmission that underlies machine to machine communications, while ODM is implemented as a relational database model for persistent data storage. Web services support access to hydrologic data stored in ODM or other repositories from application software such as Excel, MATLAB and ArcGIS that have Simple Object Access Protocol (SOAP) capability. HIS Desktop provides a local data repository and set of tools that also facilitates the integration and analysis processes. A significant value of both the web services and HIS desktop derives from the capability to use them from within a user’s preferred analysis environment, using community defined semantics, rather than requiring a user to learn new software. This paper describes the technology and tools developed as part of the CUAHSI HIS that provide: (1) Data Storage in a relational data model (ODM); (2) Data Access through internet-based Water Data Services using a consistent data language, called WaterML; (3) Data Indexing through a National Water Metadata Catalog; and (4) Data Discovery through a federated map and thematic keyword search system. The combination of these capabilities creates a common window on water observations data for the United States unlike any that has existed before, and is also extensible worldwide. For more information about the CUAHSI HIS, or to obtain the software, freely distributed under the Berkeley Software Distribution (BSD) license, go to our website: