Project area general description

The state of Connecticut

Are any areas excluded?

Flow statistics/basin characteristics not computed for the upper reaches of the Housatonic River and the mainstem of the Connecticut River due to extrapolating beyond the range of explanatory variables used in the study.

Types of flow statistics available

low flow, flow durations, and peak flows

ArcGIS version used for processing

9.3

Was TopoGrid used to process DEMs?

Yes

DEM and derivatives projection (general description)

NAD 1983 Connecticut State Plane Coordinate System FIPS 0600 Feet

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

DEM source

U.S. Geological Survey, 2006, National Elevation Dataset

Hydrography source

USGS  NHD and centerline hydrography at 1:24,000 scale developed by CT DEP (Danenberg and Bogar, 1994)

Hydrologic unit "walls" source

USDA WBD and drainage subbasins at 1:24,000 scale (Connecticut Drainage Basin Boundaries)

Gage basin boundaries source

DEM (10-meter) and WBD (24k) Global Watershed

Interactive map snapping tolerance

3 cells

Name

Description

Computation Method

Data Source

Report

Variable label in report

DRNAREA            

Area that drains to a point on a stream, in square miles            

polygon area

DEM (10 m) and WBD (24k) GlobalWatershed

Ahearn and Hodgkins (2020)

DRNAREA

I24H2Y

24 Hour 2 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H2Y

I24H5Y

24 Hour 5 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H5Y

I24H10Y

24 Hour 5 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H10Y

I24H25Y

24 Hour 25 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H25Y

I24H50Y

24 Hour 50 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H50Y

I24H100Y

24 Hour 100 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H100Y

I24H200Y

24 Hour 200 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H200Y

I24H500Y

24 Hour 500 Year Precipitation, in inches

area-weighted mean

NOAA’s National Weather Service Precipitation Frequency Data Server; https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_gis.html

Ahearn and Hodgkins (2020)

I24H500Y

SOILCCDD

Percent of hydrologic soil groups C, C/D, and D

Percent of area

Soil Survey Geographic (SSURGO) database (Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture, 2017; https://sdmdataaccess.sc.egov.usda.gov

Ahearn and Hodgkins (2020)

SoilCorD

Name

Description

Computation Method

Data Source

Report

Variable label in report

DRNAREA

Drainage area in square miles

polygon area

U.S. Geological Survey, 2006, National Elevation Dataset: accessed on June 25, 2009, at http://ned.usgs.gov.Watershed Boundary Dataset drainage boundaries (http://www.ncgc.nrcs.usda.gov/products/datasets/watershed/, accessed June 25, 2009

Ahearn (2010)

DRNAREA

CRSDFT

Coarse stratified deposits, in percent

Area of coarse stratified deposits /drainage area)*100; glacial meltwater deposits (stratified) consists of coarse deposits and stacked coarse deposits

Connecticut: Stone, J.R., Schafer, J.P., London, E.H., and Thompson, W.B., Compilation sheets at 1:24,000 scale for Stone, J.R., Schafer, J.P., London, E.H., and Thompson, W.B., 1992, Surficial materials map of Connecticut, at http://www.ct.gov/dep/cwp/view.asp?a=2698&q=322898&depNav_GID=1707#Geology. New York: New York State Geological Survey, Surficial Geology, New York State Museum Technology Center,U.S. Geological Survey Special Map, 2 sheets, scale 1:125,000, accessed on April 20, 2009, at  http://www.nysm.nysed.gov/gis.html, accessed on April 20, 2009.  Rhode Island: Glacial Deposits, Rhode Island Geographic Information System, http://www.edc.uri.edu/rigis/data/data.aspx?ISO=geoscientificInformation, accessed on April 20, 2009. Massachusetts: MassGIS, Surficial Geology (1:24,000), accessed on April 20, 2009.

Ahearn (2010)

CRSDFT

ELEV

Mean Basin Elevation, in feet

area-weighted mean

U.S. Geological Survey, 2006, National Elevation Dataset: accessed on June 25, 2009, at http://ned.usgs.gov

Ahearn (2010)

ELEV

NOVAVPRE

Precipitation 1971-2000, November, mean monthly, in inches

Averaged over the basin surface area estimated using ArcInfo Grid

Prism Climate Group, 2009, Precipitation: Corvallis, Oreg., Oregon State University, accessed on August 5, 2009, at http://www.prism.oregonstate.edu/

Ahearn (2010)

PPTnov

PRCWINTER

Precipitation 1971-2000, December-February, mean monthly, in inches

Averaged over the basin surface area estimated using ArcInfo Grid as sum of monthly averages of December, January, and February divided by 3

Prism Climate Group, 2009, Precipitation: Corvallis, Oreg., Oregon State University, accessed on August 5, 2009, at http://www.prism.oregonstate.edu/

Ahearn (2010)

PPTow

WETLAND

Wetlands, in percent

percent in area

U.S. Fish and Wildlife Service, 2009, National Wetlands Inventory: Branch of Resource and Mapping Support, accessed on August 5, 2009, at http://www.fws.gov/wetlands/

Ahearn (2010)

WETLAND