This resource provides the data and R code needed to apply the mean annual and mean monthly streamflow prediction models for Colorado presented in Eurich (2020). A web version of the shiny app for applying the models is available at https://cuahsi.shinyapps.io/CO_streamflow/.

The resource also includes attributes and streamflow values for watersheds throughout Colorado that were used to develop the models. All datasets are averages for water years 2001-2018.

Watershed attribute data to apply the models are contained in the Data folder within the CO_streamflow.zip file, with the exception of elevation, slope and aspect. Due to file size limitations, these are provided in separate compressed files. After download they should be uncompressed and moved into the Data folder. Attributes include the following spatial data files for the state of Colorado:

-Mean annual precipitation: File name p.tif. Units mm. Source PRISM Climate Group (2004).
-Mean annual potential evapotranspiration. File name pet.tif. Units mm. Source gridMET grass reference evapotranspiration (Abatzoglou 2013).
-Mean annual snow persistence. File name sp.tif. Units %. Source Hammond et al. (2017).
-Elevation: File name elevation.tif. Units m. Source 30-m digital elevation model from National Elevation Dataset.
-Aspect: Eight files for aspect bins N, NE, E, SE, S, SW, W, NW. File names aspect_bin.tif, each contained in subfolder Data/Aspect. Derived from elevation.tif.
-Slope: File name slope.tif. Units %. Derived from elevation.tif.
-Geology: File name Geology.shp. Source USDA-USGS Mineral Resources Program (2005).
-Hydrologic Region: File name HydroRegion.shp. Source Capesius and Stephens (2009).

Code to apply the models is supplied in the main folder, both as an R script (CO_Q.r) and as a Shiny app (CO_Qapp.r). Description of the code structure and source packages is available in Eurich et al. (submitted).

Streamflow data from the gauged streams are provided in the Data folder as streamflow_observed.csv. This file includes both watershed attributes derived from the same source files listed above as well as observed streamflow. The file has the following columns:

-gageID: this provides the Colorado Division of Water Resources (CDWR) gage abbreviation followed by the US Geological Survey (USGS) gage number. If no CDWR gage abbreviation is available, the value is only the USGS gage number.
-statname: this provides the full station name for the station.
-Type: this indicates whether the stream is natural or has within basin modifications. Natural streams have no documented reservoirs or flow diversions and less than 10% urban land cover. Within basin modification streams have <10% urban land cover and no transbasin diversions, but they do have reservoirs and/or diversions within the watershed.
-Area_sq.km: watershed drainage area in square kilometers
-Elev_m: watershed mean elevation in meters
-Slope_%: watershed mean slope in percent
-Dom_Aspect: aspect bin (N, NE, E, SE, S, SW, W, NW) covering the largest area in the watershed
-Geo_group: geologic group (permeable sedimentary, impermeable sedimentary, volcanic, intrusive, permeable metamorphic, impermeable metamorphic, modern alluvium/colluvium, glacial) covering the largest area in the watershed
-Hyd_reg: hydrologic region (Mountain, Northwest, Plains, Rio Grande, Southwest) of the watershed outlet
-SP: mean annual snow persistence for the watershed in %
-P_mm: mean annual precipitation for the watershed in mm
-PET_mm: mean annual potential evapotranspiration for the watershed in mm
-Qann_mm: mean annual observed streamflow in mm
-Qjan_mm: mean January observed streamflow in mm
-Qfeb_mm: mean February observed streamflow in mm
-Qmar_mm: mean March observed streamflow in mm
-Qapr_mm: mean April observed streamflow in mm
-Qmay_mm: mean May observed streamflow in mm
-Qjun_mm: mean June observed streamflow in mm
-Qjul_mm: mean July observed streamflow in mm
-Qaug_mm: mean August observed streamflow in mm
-Qsep_mm: mean September observed streamflow in mm
-Qoct_mm: mean October observed streamflow in mm
-Qnov_mm: mean November observed streamflow in mm
-Qdec_mm: mean December observed streamflow in mm
-Q1: 1st percentile non-exceedance flow in mm
-Q99: 99th percentile non-exceedance flow in mm
-CV_low: coefficient of variation for the annual low flow, unitless
-CV_high: coefficient of variation for the annual high flow, unitless