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Regionalized equations for bankfull-discharge and channel characteristics of streams in New York State—Hydrologic Region 6 in the Southern Tier of New York

Scientific Investigations Report 2005-5100

Prepared in cooperation with the New York State Department of Environmental Conservation, New York State Department of Transportation, and New York City Department of Environmental Protection
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Abstract

Equations that relate bankfull discharge and channel characteristics (width, depth, and cross-sectional area) to drainage-area size at gaged sites are needed to define bankfull discharge and channel dimensions at ungaged sites and to provide information for watershed assessments, stream-channel classification, and the design of stream-restoration projects. Such equations are most accurate if derived from streams within an area of uniform hydrologic, climatic, and physiographic conditions and applied only within that region. In New York State, eight hydrologic regions were previously defined on the basis of similar high-flow (flood) characteristics. This report presents drainage areas and associated bankfull characteristics (discharge and channel dimensions) for surveyed streams in southwestern New York (Region 6).

Stream-survey data and discharge records from 11 active (currently gaged) sites and 3 inactive (discontinued) sites were used in regression analyses to relate bankfull discharge and bankfull channel width, depth, and cross-sectional area to the size of the drainage area. The resulting equations are:

(1) bankfull discharge, in cubic feet per second = 48.0*(drainage area, in square miles)0.842;

(2) bankfull channel width, in feet = 16.9*(drainage area, in square miles)0.419;

(3) bankfull channel depth, in feet = 1.04*(drainage area, in square miles)0.244; and

(4) bankfull channel cross-sectional area, in square feet = 17.6*(drainage area, in square miles)0.662.

The coefficient of determination (R2) for these four equations were 0.90, 0.79, 0.64, and 0.89, respectively. The high correlation coefficients for bankfull discharge and cross-sectional area indicate that much of the variation in these variables is explained by the size of the drainage area. The smaller correlation coefficients for bankfull channel width and depth indicate that other factors also affect these relations. Recurrence intervals for the estimated bankfull discharge of each stream ranged from 1.01 to 2.35 years; the mean recurrence interval was 1.54 years. The 14 surveyed streams were classified by Rosgen stream type; most were C-type reaches, with occasional B-type reaches. The Region 6 equation (curve) for bankfull discharge was compared with equations previously developed for four other large areas in New York State and southeastern Pennsylvania. The differences among results indicate that, although the equations need to be refined by region before being applied by water-resources managers to local planning and design efforts, similar regions have similar relations between bankfull discharge and channel characteristics.

Suggested Citation

Mulvihill, C.I., Ernst, A.G., and Baldigo, B.P., 2005, Regionalized equations for bankfull-discharge and channel characteristics of streams in New York State—Hydrologic Region 6 in the Southern Tier of New York: U.S. Geological Survey Scientific Investigations Report 2005–5100, 14 p., https://pubs.er.usgs.gov/publication/sir20055100.

ISSN: 2328-0328 (online)

Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Regional Equations for Bankfull Discharge and Channel Characteristics of Streams
  • Limitations of This Study
  • Summary and Conclusions
  • Acknowledgments
  • References Cited

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Regionalized equations for bankfull-discharge and channel characteristics of streams in New York State—Hydrologic Region 6 in the Southern Tier of New York
Series title:
Scientific Investigations Report
Series number:
2005-5100
Year Published:
2005
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
New York Water Science Center
Description:
iv, 14 p.
Online Only (Y/N):
Y
Additional Online Files (Y/N):
Y