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Regionalized equations for bankfull-discharge and channel characteristics of streams in New York State—Hydrologic Region 7 in western New York

Scientific Investigations Report 2006-5075

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

Computation of bankfull discharge and channel dimensions (width, depth, and cross-sectional area) at ungaged sites requires equations that relate bankfull discharge and channel dimensions to drainage-area at gaged sites. Bankfull-channel information commonly is needed for watershed assessments, stream channel classification, and the design of stream-restoration projects. Such equations are most accurate if they are derived on the basis of data from streams within a region of uniform hydrologic, climatic, and physiographic conditions and applied only within that region. New York State contains eight hydrologic regions that were previously delineated on the basis of high-flow (flood) characteristics. This report presents drainage areas and associated bankfull characteristics (discharge and channel dimensions) for surveyed streams in western New York (Region 7).

Stream-survey data and discharge records from seven active and three inactive USGS streamflow-gaging stations were used in regression analyses to relate drainage area to bankfull discharge and to bankfull channel width, depth, and cross-sectional area. The resulting equations are:

(1) bankfull discharge, in cubic feet per second = 37.1*(drainage area, in square miles)0.765;

(2) bankfull channel width, in feet = 10.8*(drainage area, in square miles)0.458;

(3) bankfull channel depth, in feet = 1.47*(drainage area, in square miles)0.199; and

(4) bankfull channel cross-sectional area, in square feet = 15.9*(drainage area, in square mile)0.656.

The coefficients of determination (R2) for these four equations were 0.94, 0.89, 0.52, and 0.96, respectively. The high coefficients of determination for three of these equations (discharge, width, and cross-sectional area) indicate that much of the range in the variables was explained by the drainage area. The low coefficient of determination for the equation relating bankfull depth to drainage area, however, suggests that other factors also affected water depth. Recurrence intervals for the estimated bankfull discharge of each stream ranged from 1.05 to 3.60 years; the mean recurrence interval was 2.13 years. The 10 surveyed streams were classified by Rosgen stream type; most were C- and E-type, with occasional B- and F-type cross sections. The equation (curve) for bankfull discharge for Region 7 was compared with those previously developed for four other hydrologic regions in New York State. The differences confirm that the hydraulic geometry of streams is affected by local climatic and physiographic conditions.

Suggested Citation

Mulvihill, C.I., Ernst, A.G., and Baldigo, B.P., 2006, Regionalized equations for bankfull-discharge and channel characteristics of streams in New York State—Hydrologic Region 7 in western New York: U.S. Geological Survey Scientific Investigations Report 2006–5075, 14 p., https://pubs.er.usgs.gov/publication/sir20065075.

ISSN: 2328-0328 (online)

Study Area

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 7 in western New York
Series title:
Scientific Investigations Report
Series number:
2006-5075
Edition:
Version 1.0
Year Published:
2006
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
New York Water Science Center
Description:
iv, 14 p.
Scale:
0
Online Only (Y/N):
Y
Additional Online Files (Y/N):
Y