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Bankfull discharge and channel characteristics of streams in New York State

Scientific Investigations Report 2009-5144
Prepared in cooperation with the New York State Department of Environmental Conservation, New York Department of State, New York State Department of Transportation, and New York City Department of Environmental Protection
By: , , , , and 
https://doi.org/10.3133/sir20095144

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Abstract

Equations that relate drainage area to bankfull discharge and channel characteristics (such as width, depth, and cross-sectional area) at gaged sites are needed to help define bankfull discharge and channel characteristics at ungaged sites and can be used in stream-restoration and protection projects, stream-channel classification, and channel assessments. These equations are intended to serve as a guide for streams in areas of similar hydrologic, climatic, and physiographic conditions. New York State contains eight hydrologic regions that were previously delineated on the basis of high-flow (flood) characteristics. This report seeks to increase understanding of the factors affecting bankfull discharge and channel characteristics to drainage-area size relations in New York State by providing an in-depth analysis of seven previously published regional bankfull-discharge and channel-characteristics curves.

Stream-survey data and discharge records from 281 cross sections at 82 streamflow-gaging stations were used in regression analyses to relate drainage area to bankfull discharge and bankfull-channel width, depth, and cross-sectional area. The R2 and standard errors of estimate of each regional equation were compared to the R2 and standard errors of estimate for the statewide (pooled) model to determine if regionalizing data reduced model variability. It was found that regional models typically yield less variable results than those obtained using pooled statewide equations, which indicates statistically significant regional differences in bankfull-discharge and channel-characteristics relations.

Statistical analysis of bankfull-discharge relations found that curves for regions 4 and 7 fell outside the 95-percent confidence interval bands of the statewide model and had intercepts that were significantly diferent (p≤0.10) from the other five hydrologic regions.Analysis of channel-characteristics relations found that the bankfull width, depth, and cross-sectional area curves for region 3 were significantly different p(≤0.05) from the other six regions.

It was hypothesized that some regional variability could be reduced by creating models for streams with similar physiographic and climatic characteristics. Available data on streamflow patterns and previous regional-curve research suggested that mean annual runoff, Rosgen stream type, and water-surface slope were the variables most likely to influence regional bankfull discharge and channel characteristics to drainage-area size relations. Results showed that although all of these factors had an influence on regional relations, most stratified models have lower 2 values and higher standard errors of estimate than the regional models.

The New York statewide (pooled) bankfull-discharge equation and equations for regions 4 and 7 were compared with equations for four other regions in the Northeast to evaluate region-to-region differences, and assess the ability of individual curves to produce results more accurate than those that would be obtained from one model of the northeastern United States. Results indicated that model slopes lack significant diferences, though intercepts are significantly different. Comparison of bankfull-discharge estimates using different models shows that results could vary by as much as 100 percent depending on which model was used and indicated that regionalization improved model accuracy.

Suggested Citation

Mulvihill, C.I., Baldigo, B.P., Miller, S.J., DeKoskie, Douglas, DuBois, Joel, 2009, Bankfull discharge and channel characteristics of streams in New York State: U.S. Geological Survey Scientific Investigations Report 2009–5144, 52 p., https://pubs.er.usgs.gov/publication/sir20095144.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Bankfull Discharge and Channel Characteristics of Streams in New York State
  • New Hydrologic Regions
  • Data Stratification
  • Comparison of New York State Equations to those Developed for Other Regions in the Northeast
  • Other Uses of Regional Curves
  • Limitations of Regional Curves
  • Summary
  • Acknowledgments
  • References Cited
  • Appendix 1. Characteristics of Streamflow-Gaging Stations Surveyed in New York State, 1999–2006
  • Appendix 2. Stream Classification and Bankfull-Channel Characteristics for Streamflow-Gaging Stations Surveyed in New York State, 1999–2006
Publication type Report
Publication Subtype USGS Numbered Series
Title Bankfull discharge and channel characteristics of streams in New York State
Series title Scientific Investigations Report
Series number 2009-5144
DOI 10.3133/sir20095144
Year Published 2009
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New York Water Science Center
Description vi, 52 p.
Country United States
State New York
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
Google Analytic Metrics Metrics page
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