Basin, Climatic, and Irrigation Factors Associated with Median Summer Water Yields for Streams in Southwestern Michigan, 1945-2015

Scientific Investigations Report 2018-5071
Prepared in cooperation with the Michigan Department of Environmental Quality



Median summer water yields and resultant flows for streams are used in Michigan to regulate large water withdrawals to help prevent negative effects on characteristic fish populations. Large water withdrawals commonly are associated with irrigation in rural areas. In an earlier statewide report, an index-flow statistic for the period of record, defined as the median flow during the summer month of lowest flow, was used to characterize median summer flows and associated water yields. In this report, the annual series of median summer water yields for the period July 1 through September 30 within the period of record is used to characterize median summer water yields. For 27 streamgages included in both reports, the average index water yield was at the 37th percentile of the distribution of median summer water yields. In contrast to an index statistic, an annual time series provides a basis for detecting trends in median summer water yields and for determining basin, climatic, and irrigation factors affecting spatial and temporal variations in summer water yields. Daily flow data from 40 selected U.S. Geological Survey streamgages in southwestern Michigan were used in this analysis. Two mixed models were identified to estimate median summer water yields based on fixed basin characteristics and temporally varying climatic factors for 1945–2015. No irrigation data were available prior to 1970, so no irrigation variables were included in the mixed models for 1945–2015. Then, two mixed models were developed for 1970–2015, a period in which a partial annual series of county-level irrigation data also were available. One of the 1970–2015 mixed models provides a basis for estimating median summer water yields at sites in southwestern Michigan using an estimated trend component, and selected basin, climatic, and irrigation factors. Re-estimation of model parameters in this mixed model with more spatially precise information on irrigation withdrawals may improve model accuracy.

Suggested Citation

Holtschlag, D.J., 2019, Basin, climatic, and irrigation factors associated with median summer water yields for streams in southwestern Michigan, 1945–2015: U.S. Geological Survey Scientific Investigations Report 2018–5071, 23 p.,

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Annual Series of Median Summer Flows and the Period of Record Index Flow Statistic
  • Estimation of Median Summer Water Yields Using Mixed Models
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Basin, climatic, and irrigation factors associated with median summer water yields for streams in Southwestern Michigan, 1945-2015
Series title Scientific Investigations Report
Series number 2018-5071
DOI 10.3133/sir20185071
Year Published 2019
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Michigan Water Science Center, Upper Midwest Water Science Center
Description Report: vii, 23 p.; Data Release
Country United States
State Michigan
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details