General Information

Project area general description

The state of Colorado

Are any areas excluded?

No, but some small closed basins in the SanLuis Valley were filled to show connectivilty

Types of flow statistics available

Peak Streamflow Frequency, Annual and Monthly mean streamflow, minimum and maximum 7 day streamflow.

ArcGIS version used for processing

Originally 9.1, with some updates using 9.2

Was TopoGrid used to process DEMs?

No.

DEM and derivatives projection (general description)

UTM Zone 13, horizontal datum NAD 83, vertical datum NAVD 88

DEM and derivatives (fdr, fac, etc.) resolution

10 m

DEM source

1/3-arc-second National Elevation Dataset (NED) http://ned.usgs.gov

Hydrography source

National Hydrography Dataset (NHD)

Hydrologic unit "walls" source

8-digit HUCs only, based on draft WBD, 2007

Gage basin boundaries source

not used

Interactive map snapping tolerance

3 cells

Basin characteristics computed using continuous parameter grids (CPGs)

BSLDEM10M, ELEV, EL7500

 

Basin Characteristics Methods and Sources

Name
 Description
 Computation method
 Data Source
 Variable name in SIR 2009-5136
BSLDEM10M
 Mean basin slope computed from 10 m DEM, in percent
 Area-weighted mean of slope grid
 U.S. Geological Survey, 2007, 1/3-arc-second National elevation dataset, accessed August 13, 2007, at http://ned.usgs.gov/
S
CSL1085LFP
 10-85 slope based on longest flow path computed using 10-m DEMs, in feet per mile
 Computed
 http://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&H/NEHhydrology/ch15.pdf
DRNAREA
 Area that drains to a point on a stream in square miles
 Polygon area
 GlobalWatershed
A
EL7500
 Percentage of basin above 7500 ft elevation
 Percent of area
 U.S. Geological Survey, 2007, 1/3-arc-second National elevation dataset, accessed August 13, 2007, at http://ned.usgs.gov/
A7500
ELEV
 Mean Basin Elevation, in feet
 Area-weighted mean
 http://hdsc.nws.noaa.gov/hdsc/pfds/ accessed March 7, 2016
E
ELEVMAX
 Maximum basin elevation, in feet
 Computed
 Computed from 10-meter DEM
I24H100Y
 Maximum 24-hour precipitation that occurs on average once in 100 years
 Area-weighted mean
 http://hdsc.nws.noaa.gov/hdsc/pfds/ accessed March 7, 2016
I24H2Y
 Maximum 24-hour precipitation that occurs on average once in 2 years
 Area-weighted mean
 http://hdsc.nws.noaa.gov/hdsc/pfds/ accessed March 7, 2016
I6H2Y
 Maximum 6-hour precipitation that occurs on average once in 2 years
 Area-weighted mean
 http://hdsc.nws.noaa.gov/hdsc/pfds/ accessed March 7, 2016
I6H100Y
 Maximum 6-hour precipitation that occurs on average once in 100 years
 Area-weighted mean
 http://hdsc.nws.noaa.gov/hdsc/pfds/ accessed March 7, 2016
6P100
LAT_OUT
 Latitude of outlet


LC11BARE
 Percentage of barren from NLCD 2011 class 31
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11CRPHAY
 Percentage of cultivated crops and hay, classes 81 and 82, from NLCD 2011
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11DEV
 Percentage of developed (urban) land from NLCD 2011 classes 21-24
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11FOREST
 Percentage of forest from NLCD 2011 classes 41-43
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11GRASS
 Percentage of grassland from NLCD 2011 class 71
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11IMP
 Average percentage of impervious area determined from NLCD 2011 impervious dataset
 Area-weighted mean
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11SHRUB
 Percentage of shrub scrub from NLCD 2011 class 52
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11SNOIC
 Percent snow and ice from NLCD 2011 class 12
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11WATER
 Percent of open water, class 11, from NLCD 2011
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LC11WETLND
 Percentage of wetlands, classes 90 and 95, from NLCD 2011
 Percent of area
 http://www.mrlc.gov/nlcd2011.php accessed February 9, 2016
LFPLENGTH
 Length of longest flow path, in miles
 Computed
 Computed using the LongestFlowPath ArcHydro tool
LONG_OUT
 Longitude of outlet


MINBELEV
 Minimum basin elevation, in feet
 Computed
 Computed from 10-meter DEM
PRECIP
 Mean annual precipitation, 1971-2000, in inches
 Area-weighted mean
 Daly, Christopher, Nielson, R.P., and Phillips, D.L., 1994, A statistical-topographic model for mapping climatological precipitation over mountainous terrain: Journal of Applied Meteorology, v. 33, no. 2, p. 140–158, accessed August 15, 2007, at http://www.prism.oregonstate.edu/products/
P
RCN
 Runoff-curve number as defined by NRCS
 Area-weighted mean
 http://policy.nrcs.usda.gov/OpenNonWebContent.aspx?content=17758.wba
RUNCO_CO
 Soil runoff coefficient as defined by Dhakal (2012)
 Area-weighted mean
 http://www.academia.edu/20858598/Development_of_Guidance_for_Runoff_
Coefficient_Selection_and_Modified_Rational_Unit_Hydrograph_Method_for_
Hydrologic_Design
SSURGOA
 Percent of area hydrologic  soil 'A' defined by SSURGO
 Percent of area
 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053627 accessed January 27, 2016
SSURGOB
 Percent of area hydrologic  soil 'B' defined by SSURGO
 Percent of area
 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053627 accessed January 27, 2016
SSURGOC
 Percent of area hydrologic  soil 'C' defined by SSURGO
 Percent of area
 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053627 accessed January 27, 2016
SSURGOD
 Percent of area hydrologic  soil 'D' defined by SSURGO
 Percent of area
 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053627 accessed January 27, 2016
STORNHD
 Percent storage (wetlands and waterbodies) determined from 1:24K NHD
 Area-weighted mean
 http://nhd.usgs.gov/ accessed May 17, 2016
TOC
 Time of concentration - time required for runoff to travel from the hydraulically most distant point in the watershed to the outlet, in hours
 Computed
 Using equation 15-4b from https://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=27002.wba, with computed values of BSLDEM10M, LFPLENGTH, and RCN



The Colorado StreamStats introductory page here has additional information regarding the application, including links to reports, cooperators, and other explanatory information.