Development and evaluation of a reservoir model for the Chain of Lakes in Illinois

Scientific Investigations Report 2016-5155
Prepared in cooperation with the llinois Department of Natural Resources and the National Weather Service



Forecasts of flows entering and leaving the Chain of Lakes reservoir on the Fox River in northeastern Illinois are critical information to water-resource managers who determine the optimal operation of the dam at McHenry, Illinois, to help minimize damages to property and loss of life because of flooding on the Fox River. In 2014, the U.S. Geological Survey; the Illinois Department of Natural Resources, Office of Water Resources; and National Weather Service, North Central River Forecast Center began a cooperative study to develop a system to enable engineers and planners to simulate and communicate flows and to prepare proactively for precipitation events in near real time in the upper Fox River watershed. The purpose of this report is to document the development and evaluation of the Chain of Lakes reservoir model developed in this study.

The reservoir model for the Chain of Lakes was developed using the Hydrologic Engineering Center–Reservoir System Simulation program. Because of the complex relation between the dam headwater and reservoir pool elevations, the reservoir model uses a linear regression model that relates dam headwater elevation to reservoir pool elevation. The linear regression model was developed using 17 U.S. Geological Survey streamflow measurements, along with the gage height in the reservoir pool and the gage height at the dam headwater. The Nash-Sutcliffe model efficiency coefficients for all three linear regression model variables ranged from 0.90 to 0.98.

The reservoir model performance was evaluated by graphically comparing simulated and observed reservoir pool elevation time series during nine periods of high pool elevation. In addition, the peak elevations during these time periods were graphically compared to the closest-in-time observed pool elevation peak. The mean difference in the simulated and observed peak elevations was -0.03 feet, with a standard deviation of 0.19 feet. The Nash-Sutcliffe coefficient for peak prediction was calculated as 0.94. Evaluation of the model based on accuracy of peak prediction and the ability to simulate an elevation time series showed the performance of the model was satisfactory.

Suggested Citation

Domanski, M.M., 2017, Development and evaluation of a reservoir model for the Chain of Lakes in Illinois: U.S. Geological Survey Scientific Investigations Report 2016–5155, 21 p.,

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Purpose and Scope 
  • Model Development 
  • Model Evaluation 
  • Summary
  • References

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Development and evaluation of a reservoir model for the Chain of Lakes in Illinois
Series title Scientific Investigations Report
Series number 2016-5155
DOI 10.3133/sir20165155
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Illinois Water Science Center
Description viii, 21 p.
Country United States
State Illinois
Other Geospatial Chain of Lakes, Fox River
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
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