Stream-Gage Database Development and Network Analysis Study Area Boundary

Streamflow and basin-characteristic data are needed for a variety of scientific and managerial applications, including estimation of flow in ungaged basins and hydro-ecological classification of rivers. These data are collected by a variety of organizations, usually on a state-by-state basis. The existing network of streamflow gaging stations within the SRLCC provides much useful data. However, because it is not feasible to operate gaging stations at all locations where planning, structure design, or water-management decisions will be made, resource managers, scientists, and stakeholders need a reliable means to project information from gaged to ungaged locations using standard statistical techniques. The spatial distribution and the lengths-of-record of the existing streamflow-gaging stations can affect how well the information from the gaged locations can be assumed to represent similar ungaged locations. The quality of such projections, in turn, affects how well the stream-gage network can support important research and management needs within the SRLCC.The study area will cover four major drainage basins of the geographically diverse terrain of the SRLCC, including large parts of Colorado, Utah, Arizona, and New Mexico. The drainages proposed for inclusion in the study are the Green River, the Upper Colorado above the confluence with the Green, the San Juan, and the Little Colorado. The geospatial database will include all USGS stream gages within the study area as well as appropriate, quality-controlled gages from the included States. The upstream drainage area represented by each stream gage will be delineated, along with a suite of basin characteristics, which will facilitate a network analysis.