Lindsay Reynolds Patrick Shafroth 20160120 Raster Digital Dataset USGS Data Series 974 Denver, CO U.S. Geological Survey http://dx.doi.org/10.5066/F7H9938M Lindsay Reynolds Patrick Shafroth 20160120 Publication (U.S. Geological Survey Data Series) U.S. Geological Survey Data Series 974 Denver, CO U.S. Geological Survey http://dx.doi.org/10.3133/ds974 Our objective was to model 7-day minimum flow (mean of the annual minimums of a 7-day moving average for each year [cubic feet per second]) on small, ungaged streams in the Upper Colorado River Basin. Modeling streamflows is an important tool for understanding landscape-scale drivers of flow and estimating flows where there are no gaged records. We focused our study in the Upper Colorado River Basin, a region that is not only critical for water resources but also projected to experience large future climate shifts toward a drier climate. We used a random forest modeling approach to model the relation between 7-day minimum flow on gaged streams (115 gages) and environmental variables. We then projected 7-day minimum flow to ungaged reaches in the Upper Colorado River Basin using environmental variables for each stream cell in the basin. This data layer shows modeled values for 7-day minimum flow of each stream cell. Modeled 7-day minimum flow (mean of the annual minimums of a 7-day moving average for each year [cubic feet per second]) on small, ungaged streams in the Upper Colorado River Basin. Our map projections are useful for scientists, land owners, and policy makers to understand current hydrology in the Upper Colorado Basin and to make informed decisions regarding water resources. 20160122 2011 2015 publication date Complete Not planned 43.799831373 -113.663369597 -105.093683565 35.110223419 Upper Colorado River Basin None Streamflow Random forests Ungaged streams Streamflow modeling Upper Colorado River Basin USGS Metadata Identifier USGS:56983498e4b0fbd3f7fa3de2 None Upper Colorado River Basin none none ScienceBase U.S. Geological Survey mailing and physical

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Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov We would like to recognize the U.S. Bureau of Reclamation, WaterSMART program through the Southern Rockies Landscape Conservation Cooperative for financial support (Reclamation Grant #R11AC81525). Environment as of Metadata Creation: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2 (Build 3552) Service Pack N/A (Build N/A) No formal attribute accuracy tests were completed. No formal logical accuracy tests were completed. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. A formal accuracy assessment of the horizontal positional information in the data set has not been completed. A formal accuracy assessment of the vertical positional information in the data set has either not been completed or is not applicable. James Falcone 20111012 Vector Digital Dataset USGS USGS http://water.usgs.gov/GIS/metadata/usgswrd/XML/gagesII_Sept2011.xml Digital and/or Hardcopy Resources 20111012 20091012 20111012 publication date GAGES-II Source information used in support of the development of the dataset. Selection of historical streamgage data to train the random forest models. We selected 115 streamgages across the Upper Colorado River Basin with at least 8 years of data on small (1st-4th order), unimpacted streams. We determined 7-day minimum flow (mean of the annual minimums of a 7-day moving average for each year [cubic feet per second]) for each of the 115 study gage records. 2011 We used a random forest approach to model the relation between 7-day minimum flow at our study gage sites and environmental variables at each site. Environmental variables were derived from geographic data layers of climate (17), soils (2), geology (13), and land cover (7) for each individual raster cell in the Upper Colorad River Basin stream network (Reynolds and others, 2015; Table 2). Environmental variables were calculated or accumulated for the upstream watershed of each cell as appropriate. We then rectified our gage site locations with environmental variable raster layers for the random forests. 20120901 To fit our random forest model, we used the randomForest function of the statistical software R’s randomForest package. We completed a model selection process where environmental variables that fell below a calculated model improvement ratio were dropped from the model. We then selected the model that minimized mean square error (MSE) and maximized percentage of variation explained for each flow metric (Reynolds and others, 2015). We assessed model fit with percentage of variation explained (psuedo-R^2), MSE, and a calculated P-value for the best model for each flow metric. 20130501 To project 7-day minimum flow to ungaged reaches in the Upper Colorado River Basin, we used the environmental variables for each stream raster cell in the basin to predict 7-day minimum flow across the stream network. We used the predict function of R’s raster package, which uses the independent (environmental) variable layers and the fitted model to predict 7-day minimum flow at each stream raster cell. Because our random forest models were trained on streamgage data from small streams, we filtered out all stream cells in our projection maps with a drainage area greater than 4,000 square kilometers (1,560 square miles), or approximately 5th order and greater streams. 20130930 n/a Raster Grid Cell 31753 22864 1 North American Datum 1983 Albers (ESRI Full Name: NAD_1983_Albers) 29.5 45.5 -96.0 23.0 0.0 0.0 row and column 30.0 30.0 D_North_American_1983 GRS_1980 6378137.0 298.257222101 Attribute Table Table containing attribute information associated with the dataset. Producer defined Value Predicted 7-day minimum flow (mean of the annual minimums of a 7-day moving average for each year [cubic feet per second]) for small streams in the Upper Colorado River Basin under historic hydrologic conditions. Values shown on the map are 7-day minimum values multiplied by 1,000. Nonstream cells in the raster are represented by NoData cells. Producer defined 63 85698 Seven-day minimum flow (mean of the annual minimums of a 7-day moving average for each year [cubic feet per second]) multiplied by 1,000. Nonstream cells in the raster are represented by NoData cells. Count Count of raster cells for each value of 7-day minimum flow Producer defined 1 119524 ScienceBase U.S. Geological Survey mailing and physical

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Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner whenever applicable. The data have been approved for release and publication by the U.S. Geological Survey (USGS). Although the data have been subjected to rigorous review and are substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the data are released on the condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from authorized or unauthorized use. Although the data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. 20200820 ScienceBase U.S. Geological Survey mailing and physical

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Denver CO 80225 USA 1-888-275-8747 sciencebase@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998