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Slope Area Index (SAI) of North Carolina

Metadata Updated: October 28, 2023

Slope-Area Index (SAI) is used to predict erosion along a stream channel. It is a function of channel slope, and drainage area upstream raised to the exponent used in equations for flood frequency of 2-percent exceedance floods. The guidelines for use of the coefficient from 2-percent exceedance came from meetings with cooperators describing bankfull discharge as a 2-percent exceedance. The Slope-Area Index, as defined by Cartwright and Diehl, 2017, is calculated as: SAI = S * A^b (1) where SAI is the slope-area index, S is the channel slope, A is the drainage area (the number of cells draining into the target cell), and b is a user-specified exponent. The flood frequency report for NC (Weaver and others, 2009) defines the regional regression equations for exceedance flows for rural basins in the Southeast. The 2-percent chance exceedance flow raises the Drainage Area uses a 0.60 coefficient for all the physiographic provinces other than Small Urban basins in the Piedmont. The Urban equations drainage area coefficients for 2-percent exceedance flow (Feaster and others, 2014) were used for Piedmont (HLR2) urban basins. Urban basins were defined as catchments which were greater than 10% developed (urban). For piedmont (HLR2, small urban le 3 dasqmi and pcturb gt 10%) SAI = slope*da^0.8 For piedmont (HLR2, small urban dasqmi gt 3 and le 436 and pcturb ge 10%) SAI = slope * da^.5

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Created Date June 1, 2023
Metadata Updated Date October 28, 2023

Metadata Source

Harvested from DOI EDI

Additional Metadata

Resource Type Dataset
Metadata Created Date June 1, 2023
Metadata Updated Date October 28, 2023
Publisher U.S. Geological Survey
Identifier USGS:5b72ee9fe4b0f5d5787c5723
Data Last Modified 20200827
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id e6f4939c-3492-4a1d-8ba3-705303693abc
Harvest Source Id 52bfcc16-6e15-478f-809a-b1bc76f1aeda
Harvest Source Title DOI EDI
Metadata Type geospatial
Old Spatial -84.6982,33.4746,-75.3018,37.5216
Publisher Hierarchy White House > U.S. Department of the Interior > U.S. Geological Survey
Source Datajson Identifier True
Source Hash ad3f2c0511fc44aea19e76256620dbeb1d5ec5f2f3b0e86cdcb579bae1c18491
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": -84.6982, 33.4746, -84.6982, 37.5216, -75.3018, 37.5216, -75.3018, 33.4746, -84.6982, 33.4746}

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