General Information

Project area general description
The state of Iowa
Are any areas excluded?
The Mississippi and Missouri River mainstems.
Types of flow statistics available
Peak flow, Low flow, General flow, Seasonal flow and Flow-Duration
ArcGIS version used for processing
9.3
Was TopoGrid used to process DEMs?
Yes
DEM and derivatives projection (general description)
projected from decimal degrees to Universal Transverse Mercator (UTM) Zone 15
DEM and derivatives (fdr, fac, etc.) resolution
 10 m
DEM source
National Elevation Dataset (NED), https://nationalmap.gov/elevation.html
Hydrography source
National Hydrography Dataset (NHD) High resolution 1:24,000; https://nhd.usgs.gov/NHD_High_Resolution.html
Hydrologic unit "walls" source
Watershed Boundary Dataset (WBD), https://nhd.usgs.gov/wbd.html
Gage basin boundaries source
Watershed delineation tools in ArcHydro using hydro-corrected DEM and WBD
Interactive map snapping tolerance
3 cells


Basin Characteristics Methods and Sources


Name
Description
Computation Method
Data Source
Report
Variable label in report
BASLENAH
Basin Length ArcHydro Method in miles
length
USGS DEM (150 m), WBD (24k)
SIR 2013-5086
BASLEN
BFI
Base Flow Index
grid value at location
USGS kriged BFI grid
SIR 2012-5171
BFI
BSHAPE
Basin Shape (BSHAPE = BasinLength^2 / DRNAREA)
computed
USGS DEM (10 m), WBD (24k)
SIR 2013-5086
BSHAPE
BSLDEM10M
Average basin slope in percent from 10m DEM
area-weighted mean
DEM (10 m) http://nationalmap.gov/elevation.html
SIR 2016-5111
BSLDEM10M
CCM
CCM = Drainage Area / Sum of Stream Lengths
computed
USGS DEM (10 m), WBD, NHD (24k)
SIR 2013-5086
CCM
CSL10_85
10-85 stream slope method in feet per mile.
computed
DEM (10 m) http://nationalmap.gov/elevation.html; NHD (24K) http://nhd.usgs.gov/
SIR 2015-5055
CSL1085LFP
CSL100
Longest flow path slope in feet per miles, using DEM
computed
DEM (10 m) http://nationalmap.gov/elevation.html; NHD (24K) http://nhd.usgs.gov/
SIR 2015-5055
CSL100
DESMOIN
Percent covered by Des Moines Lobe
percent of area
Iowa Geological & Water Survey, IDNR grid
SIR 2013-5086
DESMOIN
DRNAREA
Area in square miles
polygon area
DEM (10 m) http://nationalmap.gov/elevation.html; WBD (24K) https://gdg.sc.egov.usda.gov/
SIR 2013-5086, SIR 2012-5171, SIR 2016-5111, SIR 2012-5232
DRNAREA
DRNFREQ
Drainage Frequency = First Order Streams / Drainage Area
computed
DEM (10 m) http://nationalmap.gov/elevation.html; WBD (24K) https://gdg.sc.egov.usda.gov/; NHD (24K) http://nhd.usgs.gov/
SIR 2012-5171, SIR 2016-5111
DRNFREQ
FOSTREAM
Number of first order streams
sum
DEM (10 m) http://nationalmap.gov/elevation.html; NHD (24K) http://nhd.usgs.gov/
SIR 2012-5171, SIR 2016-5111
FOSTREAM
HIGHREG
Peakflow Region number




HYSEP
Percent of area covered by  Hydrograph Separation
median percentage of baseflow to annual streamflow
Elevation characteristics are determined from the U.S. Geological Survey (USGS) 30-meter National Elevation Dataset
SIR 2012-5232
HYSEP
I24H10Y
24 Hour 10 Year Precipitation, in inches
area-weighted mean
Midwest Climate Center Bulletin 71
SIR 2013-5086
I24H10Y
LC11CRPHAY
Percent area of cultivated crops and hay from NLCD 2011 classes 81 and 82
percent of area
Homer and others (2015); http://www.mrlc.gov/nlcd2011.php
SIR 2016-5111
LC11CRPHAY
LC11DEV
Percentage of urban land cover determined from NLCD 2011 land cover dataset
percent of area
Homer and others (2015); http://www.mrlc.gov/nlcd2011.php
SIR 2016-5111
LC11DEV
LC11IMP
Percentage of impervious area determined from NLCD 2011 impervious dataset
area-weighted mean
Homer and others (2015); http://www.mrlc.gov/nlcd2011.php
SIR 2016-5111
LC11IMP
PRECIP
Mean Annual Precipitation
area-weighted mean
Midwest Climate Center Bulletin 71
SIR 2012-5232
PRECIP
PRJULDEC10
Mean July to December precipitation 1981-2010 (inches)
area-weighted mean
PRISM Climate Group (2016); http://www.prism.oregonstate.edu/normals/
SIR 2016-5111
PRJULDEC10
RSD
RSD = (First Order Streams * DRNAREA / summ of Stream Lengths ^2)
computed
USGS DEM (10 m), WBD, NHD (24k)
SIR 2012-5171, SIR 2012-5232
RSD
SSURGOA
Percent of area in hydric soil 'A' defined by SSURGO
percent of area
NRCS SSURGO Web Soil Survey http://websoilsurvey.sc.egov.usda.gov/
SIR 2012-5171, SIR 2016-5111
SOILASSURGO                   SSURGOA
SSURGOB
Percent of area in hydric soil 'B' defined by SSURGO
percent of area
NRCS SSURGO Web Soil Survey http://websoilsurvey.sc.egov.usda.gov/
SIR 2012-5171, SIR 2012-5232
SOILBSSURGO
SSURGOC
Percent of area in hydric soil 'C' defined by SSURGO
percent of area
NRCS SSURGO Web Soil Survey http://websoilsurvey.sc.egov.usda.gov/
SIR 2012-5171, SIR 2016-5111, SIR 2012-5232
SOILCSSURGO            SSURGOC          SOILCSSURGO
SSURGOD
Percent of area in hydric soil 'D' defined by SSURGO
percent of area
NRCS SSURGO Web Soil Survey http://websoilsurvey.sc.egov.usda.gov/
SIR 2016-5111, SIR 2012-5232
SSURGOD             SOILDSSURGO
SSURGOKSAT
Average saturated hydraulic conductivity from SSURGO, in micrometers per second
area-weighted mean
NRCS SSURGO Web Soil Survey http://websoilsurvey.sc.egov.usda.gov/
SIR 2013-5086, SIR 2012-5171
KSATSSUR
STREAM_VARG
Streamflow Variability Index
grid value at location
USGS kriged STREAM_VAR grid
SIR 2012-5171, SIR 2012-5232
STREAM_VAR
STRMTOT
Sum of stream lengths
sum
USGS DEM NHD (24k)
SIR 2013-5086, SIR 2012-5171
STRMTOT
TAU_ANN_G
Percent of area covered by  Tau Annual
percent of area
USGS kriged TAU_ANN grid
SIR 2012-5171
TAU_ANN


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