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Low-Flow Statistics for Selected Streams in New York, Excluding Long Island

Scientific Investigations Report 2024-5055
Prepared in cooperation with the New York State Department of Environmental Conservation
By: , , , , and 
https://doi.org/10.3133/sir20245055

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Abstract

The U.S. Geological Survey, in cooperation with the New York State Department of Environmental Conservation, updated low-streamflow statistics for New York, excluding Long Island and including hydrologically connected watersheds in bordering States, for the first time since 1972. Historical daily streamflow data for active and inactive gages were considered for this study with periods of record as recent as March 31, 2022, adding 50 years of data to the last published low-streamflow statistics report for New York and including 119 new gages where low-streamflow statistics are calculated for the first time. Gages were evaluated across several criteria to identify gages that were not suitable for low-streamflow frequency analysis. In addition, gages were evaluated for the presence of alteration within the streamflow period of record based on previous studies and U.S. Geological Survey National Water Information System site metadata including peak flow codes.

A trend analysis was performed using the Wilcoxon rank-sum hypothesis test comparing data from the most recent 30 years of record to data from 30 years and earlier for each long-record gage (30 years or more of available data). Results from the trend analysis indicated that 45 unaltered and 32 altered long-record sites had a statistically significant trend for the annual minimum n-day time series; most gages showed increasing trends in the annual minimum n-day time series. Low-streamflow statistics were calculated using the most recent 30 years of record for gages with a statistically significant trend. Before and after 1972, the lowest annual 7-day and 30-day average streamflow that occurs (on average) once every 10 years (7Q10 and 30Q10 statistics respectively) increased significantly at 41 unaltered gages and decreased significantly at 3 unaltered gages where data were available.

Suggested Citation

Stagnitta, T.J., Graziano, A.P., Woda, J.C., Glas, R.L., and Gazoorian, C.L., 2024, Low-flow statistics for selected streams in New York, excluding Long Island: U.S. Geological Survey Scientific Investigations Report 2024–5055, 39 p., https://doi.org/10.3133/sir20245055.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Study Area and Gage Selection
  • Methods for Calculating At-Site Low-Streamflow Statistics
  • Low-Streamflow Nonexceedance Frequency Analysis
  • Results
  • Discussion
  • Summary
  • References Cited
  • Appendix 1. Low-Streamflow Statistics for 213 Unaltered and 79 Altered Gages
Publication type Report
Publication Subtype USGS Numbered Series
Title Low-flow statistics for selected streams in New York, excluding Long Island
Series title Scientific Investigations Report
Series number 2024-5055
DOI 10.3133/sir20245055
Year Published 2024
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New York Water Science Center
Description Report: vi, 39 p.; Data Release
Country United States
State New York
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details