This data collection consists of a synthetic stream network and associated catchments developed as the foundation for a Spatially Referenced Regressions on Watershed Attributes (SPARROW) dissolved-solids source and transport model for the Upper Colorado River Basin (UCRB). The SPARROW model requires a hydrologically connected representation of a stream network through which loads are transported from an upstream reach to the next reach downstream (Schwarz and others, 2006; Moore and others, 2004). Each stream reach or segment within this synthetic stream network has an associated local drainage area or catchment used to calculate catchment characteristics that may have an effect on loads being modeled. The synthetic stream reach network and associated catchments created for this SPARROW model were modified from the network used in a 2009 model (Kenney and others, 2009). The data were assembled using a digital elevation model (DEM) and the Medium Resolution National Hydrography Dataset (NHD). The data were developed using ArcHydro and Streamstats methods in the ArcGIS processing environment. References cited: Kenney T.A., Gerner S.J., Buto S.G., and Spangler L.E., 2009, Spatially referenced statistical assessment of dissolved-solids load sources and transport in streams of the Upper Colorado River Basin: U.S. Geological Survey Scientific Investigations Report 2009-5007, 50 p. Moore, R.B., Johnson, C.M., Robinson, K.W., and Deacon, J.R., 2004, Estimation of total nitrogen and phosphorus in New England streams using spatially referenced regression models: U.S. Geological Survey Scientific Investigations Report 2004-5012, http://pubs.usgs.gov/sir/2004/5012/ Schwarz, G.E., Hoos, A.B., Alexander, R.B., and Smith, R.A., 2006, The SPARROW surface water-quality model-theory, applications, and user documentation: U.S. Geological Survey Techniques and Methods, book 6, chap. B3, 248 p., http://pubs.usgs.gov/tm/2006/tm6b3/contents.htm