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.