Methods for Estimating Selected Low-Flow Statistics at Gaged and Ungaged Stream Sites in Massachusetts

Scientific Investigations Report 2025-5082
Prepared in cooperation with the Massachusetts Department of Conservation and Recreation, Office of Water Resources
By: , and 

Links

  • Document: Report (7.49 MB pdf) , HTML , XML
  • Data Releases:
    • USGS data release - Low-flow statistic equations and supplementary data for Massachusetts
    • USGS data release - MODPATH6 datasets using MODFLOW and SEAWAT input for development of groundwater contributing areas for estimating low-flow statistics for the Plymouth-Carver aquifer area and Cape Cod, Massachusetts
    • USGS data release - Low-flow statistic equations and supplemental data for the Plymouth-Carver Kingston-Duxbury aquifer area in southeastern Massachusetts and Cape Cod
  • Download citation as: RIS | Dublin Core

Abstract

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Conservation and Recreation, Office of Water Resources, computed selected at-site streamflow statistics at U.S. Geological Survey streamgages in and near Massachusetts and developed regional regression equations for estimating selected streamflows at ungaged stream sites in Massachusetts. Two sets of regional regression equations were developed: (1) the “mainland” equations, for mainland Massachusetts excluding the area covered by the second set, and (2) the “southeastern” equations, for the Plymouth-Carver-Kingston-Duxbury aquifer area in southeastern Massachusetts and for Cape Cod. The regression equations and at-site statistics may be used by Federal, State, and local water managers in addressing water-resources issues relevant in Massachusetts.

Regional regression analyses for the mainland equations were developed to estimate the following 27 streamflow statistics: 99-, 98-, 95-, 90-, 85-, 80-, 75-, 70-, 60-, and 50-percent flow durations; monthly June, July, August, and September 90- and 50-percent flow durations; February, June, and August median of the monthly means; harmonic mean; and medians of the following annual low-flow frequency statistics: 7-day; 7-day, 2-year; 7-day, 10-year; 30-day, 2-year; and 30-day, 10-year. The analyses used 81 streamgages with minimal to no regulations in and near Massachusetts. The regression analyses determined that four basin characteristics—drainage area, combined hydrologic soils A and B, streamflow variability index, and annual mean temperature—were the only significant explanatory variables for the different mainland equations.

Regional regression equations were developed for the Plymouth-Carver-Kingston-Duxbury aquifer area in southeastern Massachusetts and Cape Cod, because surface-water drainage areas and groundwater contributing areas do not always coincide in this area of the State. The regression analyses to estimate 10 flow durations from the 99th to 50th percentiles used 18 streamflow sites with some occasional minor regulations—because there are few unregulated streams in southeastern Massachusetts. The analyses determined that groundwater contributing area and storage (combined water bodies and wetlands) were the only significant explanatory variables in the southeastern equations.

Suggested Citation

Bent, G.C., Ahearn, E.A., and Fair, J.H., 2025, Methods for estimating selected low-flow statistics at gaged and ungaged stream sites in Massachusetts: U.S. Geological Survey Scientific Investigations Report 2025–5082, 76 p., https://doi.org/10.3133/sir20255082.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Development of Low-Flow Statistics and Basin-Characteristic Datasets for Massachusetts
  • Methods for Estimating Selected Low-Flow Statistics in Mainland Massachusetts
  • Development of Low-Flow Statistics and Basin-Characteristic Datasets for Southeastern Massachusetts and Cape Cod
  • Methods for Estimating Selected Low-Flow Statistics in Southeastern Massachusetts
  • Limitations of Regression Equations
  • StreamStats Application and Considerations for Additional Studies
  • Summary and Conclusions
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Methods for estimating selected low-flow statistics at gaged and ungaged stream sites in Massachusetts
Series title Scientific Investigations Report
Series number 2025-5082
DOI 10.3133/sir20255082
Publication Date September 19, 2025
Year Published 2025
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New England Water Science Center
Description Report: ix, 76 p.; 3 Data Releases
Country United States
State Massachusetts
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Additional publication details