Link to USGS home page.
Publications— Scientific Investigations Reports

Changes in the Magnitude of Annual and Monthly Streamflows in New England, 1902-2002

U.S. Geological Survey Scientific Investigations Report 2005-5135

By Glenn A. Hodgkins and Robert W. Dudley


This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

View the full report in PDF 3 MB

ABSTRACT

Selected annual and monthly streamflow statistics for 27 streamflow-gaging stations in New England were computed and tested for changes over time. These 27 stations were considered to be free of substantial human influences such as regulation, diversion, and land use-changes and have an average of 71 years of record. The longest streamflow record extended from 1902 to 2002.

March mean streamflows increased significantly over time (Mann-Kendall test, p < 0.1) at 14 streamflow-gaging stations in northern New England, primarily in northern or mountainous sections of Maine, New Hampshire, and Vermont. March mean flows increased by 76 to 185 percent at the seven stations with the longest continuous records in areas of New England with the largest seasonal snowpack depths. These streamflow-gaging stations had continuous records from the late 1920's and the early 1930s through 2002. May mean streamflows significantly decreased at 10 stations in northern or mountainous sections of Maine and New Hampshire. May mean flows decreased by 9 to 46 percent at the seven stations with the longest continuous records. Despite the fact that March percentage increases were much larger than May percentage decreases, March streamflow increases (in cubic feet per second) were smaller than May decreases, except at one streamflow-gaging station. Increased March and April air temperatures over time may have caused earlier snowmelt and thus increased streamflows in March and decreased streamflows in May.

There were no significant changes over time in annual mean streamflows at the 27 stations; however, there were significant increases over time in various annual percentile streamflows (minimum, 25th percentile, median, 75th percentile, or maximum flows) at 22 of the stations. This indicates that flows increased over time at many streams in New England, but the increase was not enough to have caused significant changes in annual mean flows. October mean streamflows increased significantly at five stations in western New England. December minimum streamflows increased significantly at 13 stations in northern and southern New England.

Table of Contents

Abstract

Introduction

Description of Climate and Streamflow in New England

Methods of Streamflow Data Collection and Analysis

Selection of Streamflow-Gaging Stations

Analysis of Streamflow Data

Annual and Monthly Mean Streamflows in New England

Annual and Monthly Percentile Streamflows in New England

Summary

References Cited


 

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

View the full report in PDF 3 M B

U.S. Department of the Interior, U.S. Geological Survey
Persistent URL:
Page Contact Information: Contact USGS
Last modified: Thursday, December 01 2016, 06:44:20 PM
FirstGov button  Take Pride in America button