Global Multiscale Hydrologic Web Services

There are two problems slowing widespread adoption of spatially enabled hydrologic analysis, accessibility of data, and ease of use. This paper will describe and illustrate a system for sharing hydrologic analyses (geoprocessing) services and workflows that empowers GIS professionals, scientists, and citizens by making water data and its analysis accessible to a wide audience. The system leverages recent evolutions and standards in the information technology and GIS industries, particularly web services accessed through simple geospatial browser applications, cloud computing, and the increasing amount of elevation and hydrologic observations data. The GIS foundation of the system includes a high cartographic quality base map, an attributed vector hydrologic network, a hydrologically conditioned DEM, and linkage to temporal observation data. The system will provide a set of analytic services bound to best-available, authoritative data, and include tools and workflow documentation to enable others to more easily build similar systems. A key feature of the system is the development and serving of hydrologically conditioned elevation data at multiple scales. These datasets are the basis of geoprocessing services for interactive watershed delineation and flow tracing. Geoprocessing overlay services combine these areas with descriptive landscape information to explain or predict water quantity and quality. Extensive national and global datasets exist for land cover, soils, precipitation, and water observations, and are combined to provide hydrologic information in a highly accessible and interactive way. This system of web services is useful for GIS professional who may lack the time or skills needed to assemble and process all the needed data layers. But more importantly the system is critical to a large community of scientists, professionals, and citizens who want or need more detailed and useful water information in an easily accessible way.