Extending Seasonal Discharge Records for Streamgage Sites on the North Fork Fortymile and Middle Fork Fortymile Rivers, Alaska, through Water Year 2019

Scientific Investigations Report 2020-5003
Prepared in cooperation with U.S. Bureau of Land Management
By:

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Abstract

Daily mean discharge values were estimated for May 20–September 30 for 1976–82 and 2006–18 for the U.S. Geological Survey North Fork Fortymile River and Middle Fork Fortymile River streamgage sites in Alaska. A relation between study streamgage discharge and discharge for an index streamgage on the main-stem Fortymile River for a concurrent period in 2019 was developed using the maintenance of variance extension type 3 (MOVE.3) record extension technique. The relation for North Fork Fortymile River discharges incorporated a 1-day-earlier offset to index streamgage discharges. No offset was applied to the index streamgage discharges for use with the Middle Fork Fortymile River discharges. The developed MOVE.3 regressions were used to estimate daily mean discharges at the study streamgage sites during the study season for the longer period of record of the index streamgage. The modified Nash-Sutcliffe efficiency coefficients for the estimated records were 0.38 and 0.63 for the North Fork Fortymile River and Middle Fork Fortymile River streamgages, respectively.

Suggested Citation

Curran, J.H., 2020, Extending seasonal discharge records for streamgage sites on the North Fork Fortymile and Middle Fork Fortymile Rivers, Alaska, through water year 2019: U.S. Geological Survey Scientific Investigations Report 2020–5003, 11 p., https://doi.org/10.3133/sir20205003.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods for Estimating Extended Daily Mean Discharge Records
  • Extended Daily Mean Discharge Records and Error Analysis
  • Summary
  • References Cited
  • Appendix 1

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Extending seasonal discharge records for streamgage sites on the North Fork Fortymile and Middle Fork Fortymile Rivers, Alaska, through water year 2019
Series title Scientific Investigations Report
Series number 2020-5003
DOI 10.3133/sir20205003
Year Published 2020
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Alaska Science Center Water
Description Report: iv, 11 p.; 1 Appendix
Country United States
State Alaska
Other Geospatial North Fork Fortymile River, Middle Fork Fortymile River
Online Only (Y/N) Y
Additional Online Files (Y/N) Y