The Hydrologic Information System Project of the Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) has successfully created a large-scale prototype Hydrologic Information System (HIS). This system catalogs and provides access to over 23 million time series of hydrologic data, which are distributed across the United States at various academic, research, and governmental data providers. The service-oriented architecture that enables the HIS comprises distributed hydrologic data servers, a centralized series catalog, and various client software applications, and is supported by WaterML, a standardized language for transmission of hydrologic data. The current architectural model, termed the Network-Observations Model, of the HIS relies on a searchable central catalog of series metadata. Harvesting series metadata from large federal data providers, such as the USGS, EPA, and NCDC, has proven a laborious undertaking and involves custom database migration tools. This time-consuming harvesting task, coupled with a multitude of custom-coded solutions at the central series catalog has led to concerns with the long-term sustainability of the current architectural model. A new architectural model, termed the Services Stack Model, is proposed in this thesis. In the proposed model, a catalog of services metadata, rather than of series metadata is used to connect hydrologic data consumers with data providers. Internationally-recognized web service and data encoding standards, including the upcoming WaterML2.0 specification, from the Open Geospatial Consortium are used as the backbone of the new model. The proposed model will hopefully lead to greater acceptance of the CUAHSI-HIS, and result in increased sustainability and reduced maintenance of the system in the long-term. / text

Texas water availability modeling has undergone a transition from paper-based documents to digital databases and GIS maps. This results in many discrete components: a water rights database, a GIS database, a monthly flow simulation model to quantify water availability, and an environmental flows assessment to quantify how much water should remain in Texas rivers. This dissertation examines how these components can be connected by a conceptual model and automated as a Hydrologic Information System (HIS) for Texas water availability modeling using custom GIS toolsets and data processing. The HIS is defined using three tools that combine components of the conceptual model. These tools automate the processes of water availability modeling and synthesize the conceptual model components. This dissertation also explores how desktop-based Texas water availability modeling can be informed by web services and how a services-oriented architecture for water availability modeling could be constructed. Existing hydrologic information models are used as a guide in creating an Arc Hydro Web information model as a framework for this activity. This model is demonstrated using scenarios highlighting its capabilities for representing desktop and web-informed analyses. The functionality of Arc Hydro Web is demonstrated via a use case of five associated component studies in the San Jacinto Basin illustrating the functionality of the HIS of water availability modeling in Texas. The shift from desktop-based analyses to web-enabled processing enables certain aspects of water availability modeling being moved to cloud computing. The network aspects of the Texas water availability modeling environment can be informed by web services using a centrally-stored network, negating the current system of having nearly-identical duplicate networks. This could foster communication and sharing of water resources models. It is recommended that Arc Hydro Web be implemented, that aspects of water availability modeling processing become web-enabled through the combination of web processing and web services, and that additional services be developed to meet the needs of web-based water availability modeling. / text