This document provides an overview of the Lake Michigan Diversion in Chicago, Illinois. It discusses the historic background of water management in Chicago dating back to the 1800s. It describes the various Supreme Court decrees that placed limits on water diversion from Lake Michigan. It outlines the responsibilities and structures involved in the diversion, including direct diversions through lakefront control structures, water supply from Lake Michigan, and runoff from the diverted watershed. It also summarizes the findings of technical committees regarding compliance with diversion limits and advancements in flow measurement technology.

1. LAKE MICHIGAN DIVERSION
WILLIAM H. ESPEY JR., Ph.D., P.E., D.WRE, Dist.M.ASCE
LJA ENGINEERING – Director of Water Resources

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• Surface Area: 22,404 mil²
• Volume: 1,180 cubic
miles
• Largest lake entirely
within one country (USA)
by surface area
• Fifth largest lake in the
world
LAKE MICHIGAN

3. Overview of Lake Michigan Diversion
• Historic Background
• Supreme Court Decrees
• Responsibilities for Diversion
• Lake Michigan Diversions
• Lakefront Control Structures
• Lockport Structures
• Diversion Accounting
Process
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Chicago River Entrance - Lake Michigan 1820

4. Fort Dearborn -1831
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5. Chicago River - 1853
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Historic Background
• Prior to diversions, Chicago &
Calumet Rivers flowed to Lake
Michigan
• I&M Canal constructed in 1848,
diverting 500 cfs
• Between 1850-1890 saw major
outbreaks of typhoid, cholera and
other water borne diseases as storm
events flushed city’s wastewater far
out into the lake
• Sanitary District of Chicago (now
MWRDGC) established in 1889 by
Illinois legislature
• Construction of the Chicago Sanitary
and Ship Canal (CSSC) began in 1892

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Typhoid, dysentery, and cholera jeopardized Chicago’s future. In 1854
alone, more than 1,400 Chicagoans died of cholera.
In 1855, Chicago enlisted the help of engineer Ellis Chesbrough to help solve its
water crisis. Ellis had built Boston’s water supply system.

8. CHICAGO RIVERCHICAGO RIVER
• Lockport Powerhouse went
online in 1908
• North Shore Channel (NSC) and
Wilmette Pumping Station were
constructed between 1907 and
1910 to flush Lake Michigan
water through the NBCR.
• Calumet-Sag Channel and Blue
Island Lock were completed in
1922.
• Calumet- Sag Channel was
enlarged in 1960
• O’Brien Lock and Dam was
constructed in 1965
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Development of Chicago Sanitary and Ship
Canal System – Before Canal Construction
Development of Chicago Sanitary and Ship
Canal System – Chicago Sanitary and Ship
Canal System Completed.

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Chicago River – Opened – to Chicago Drainage Canal
January 2, 1900

12. Supreme Court Decrees
Regulating the Lake Michigan Diversion
• 1925 Decree
• 8,500 cfs total limit
• 1930 Decree
• 6,500 cfs and domestic pumpage (July 1, 1930)
• 5,000 cfs and domestic pumpage (December 31, 1935)
• 1,500 cfs and domestic pumpage (December 31, 1938)
• 1967 Decree
• 3,200 cfs total limit with 3,520 cfs maximum annual average
• 5 year accounting period
• 1980 Modification of 1967 Decree
• 3,200 cfs total limit with 3,840 cfs maximum annual average
• 40 year accounting period
• Within 40 years, may exceed 3,680 cfs twice
• Cumulative annual exceedance not over 2,000 cfs
• Technical Review Committee to determine the best current engineering practice
and scientific knowledge for measuring the diversion and to make
recommendations as appropriate.
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13. HISTORY OF LAKE MICHIGAN DIVERSION 13

14. LAKE MICHIGAN DIVERSION
TECHNICAL COMMITTEES
Chairperson Flow Measurement
Expert
Modeling Expert
First (1981) Dr. Bill Espey Harry Barnes, Jr. Dr. Svein Vigander
Second (1986) Dr. Bill Espey Harry Barnes, Jr. David Westfall
Third (1993) Dr. Bill Espey Oscar Lara Dr. Robert Barkau
Fourth (1998) Dr. Bill Espey Dr. Arthur Schmidt Dr. Robert Barkau
Fifth (2003) Dr. Bill Espey Dean Mades Dr. Steve Melching
Sixth (2008) Dr. Bill Espey Dr. Marian Muste Dr. Steve Melching
Seventh (2013) Dr. Bill Espey Dr. Bert Clemmens Bruce Halverson
Eighth (2018) Dr. Bill Espey Dr. Marian Muste Dr. Steve Melching

15. Responsibilities for Diversion
1980 Decree, 1986 WRDA
• State of Illinois
• Water allocation
• Corps of Engineers
• Responsible for diversion computations, effective October
1, 1987
• United States Geological Survey
• Expert consultant for flow measurements
• Metropolitan Water Reclamation District of Greater Chicago
• Measurements of direct diversions through lakefront
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1981 - First Technical Committee
Summary of Some Key Findings
• “During the course of the study, the Committee was made keenly
aware that the measuring and accounting process lacked
credibility.”
• “The Lockport flow components are deficient in practically every
aspect.”
• “In the Committee’s view every component is deficient with
respect to quality assurances.”

17. Total Canal Flow
- Non-Diversion Flows
+ Bypassed Flows
= Total Diversion
Accountable to Illinois
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LMDA Computation
Lemont
AVM

18. • Direct Diversions through three
lakefront structures
• Runoff from diverted Lake
Michigan watershed discharged
to the canal
• Water Supply from Lake
Michigan discharged to the canal
system
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Lake Michigan Diversions

19. CHICAGO RIVER CONTROLLING WORKS
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20. Harrison-Dever Cribs
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Jardine Water Filtration/Purification Plant – (One billion gals/day)
Service – 5.5 million Chicago residents and 118 suburbs

22. •Lockage
•Navigation Makeup
•Discretionary
•Leakage
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Direct Diversions

23. Lakefront Control Structures
•Chicago River
Controlling Works
(CRCW)
•O’Brien Lock and
Dam
•Wilmette Pumping
Station
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Leakage at the Chicago River Controlling Works has been substantially reduced because of
repairs to the lock and turning basin walls (completed Summer 2000), combined with
recent lower Lake Michigan water levels.
Leakage – Chicago River Controlling Works

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Preliminary review of O’Brien L&D AVM/ADCP records suggest possible leakage. Continuous gaging of
O’Brien L&D and supporting analysis may indicate leakage through the control structure. AVM and
ADCP measurements at the O’Brien L&D AVM gage suggest that there is considerable (100 cfs or more)
leakage through the structure. Such leakage will likely increase as lake levels rise. Continuous gaging of
flows at this station together with synoptic ADCP measurements during low flow and verification of
gate opening indicators will help to better quantify the apparent leakage at this lakefront location.
Leakage – O’Brien L&D

26. Wilmette Pumping Station
•Located north of
Chicago
•Three sluice gates
•One 150 cfs pump
•One 250 cfs pump
(back-up)
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Wilmette Harbor Aerial with Baha'i
Temple

27. Lockport Structures
Construction MWRD - 1907
•Lockport power
house – 30,000 KW
•Lockport controlling
works
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30. Lockport Power House
•Two turbines
•One navigation lock
•Nine sluice gates
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31. Lockport Controlling Works
•Seven sluice gates
•Eight permanently
bulkheaded
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Lake Michigan Diversion

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TARP
TARP is the Metropolitan Water Reclamation
District’s (MWRD) large scale engineering
project designed to reduce flooding and
combined sewer overflows (CSOs) within the
MWRD’s service area including the Chicago
River watershed in Cook County, an area that
includes Chicago and dozens of other
communities. A primary purpose is to reduce
CSOs, basement flooding, and backflows into
Lake Michigan by using a combination of
tunnels and reservoirs to store combined
stormwater and sewage after heavy rainfalls
until it can be treated, rather than discharging
the polluted mess into local waterways.
109 miles of tunnels. (Diameter 8 ft – 35 ft,
length 110 miles, max depth 350 ft.)

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36. DESCRIPTION OF THE DIVERSION ACCOUNTING COLUMNS
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38. MEASURED DATA USED FOR ANNUAL DIVERSION ACCOUNTING (EPEY ET AL., 2014)*

39. DESCRIPTION OF THE DIVERSION ACCOUNTING COMPUTATIONAL BUDGETS
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40. BUDGET AND COLUMN INTERACTIONS
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41. Lake Michigan Diversion
Accounting budget (B) flow
chart . Most of the diversion
accounting budgets are used
to compare simulated flows to
recorded flows to assess the
accuracy of the diversion
accounting.
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42. Lake Michigan Cumulative Deviation from the Allowable Diversion, Annual Lake Michigan Pumpage, Diverted Watershed Runoff,
Direct Diversion and Lockport/Romeoville/Lemont/ Annual Flows, and Lake Michigan/ Huron Levels for 1981 – 2011.
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43. 1,000.0
1,100.0
1,200.0
1,300.0
1,400.0
1,500.0
1,600.0
2004 2006 2008 2010 2012 2014
Lake Michigan Pumpage by Illinois vs Chicago
Illinois Chicago
1,000.0
1,500.0
2,000.0
2,500.0
3,000.0
3,500.0
2004 2006 2008 2010 2012 2014
Total Diversion vs LM Pumpage by Chicago
Illinois Chicago
Lake Michigan by Illinois and Chicago Total Diversion vs. Lake Michigan Pumpage by Chicago

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Specifically, the technology that
has evolved with respect to
acoustical flow measurements has
not only met the standard of “best
current engineering practice and
scientific knowledge,” but the
USACE and the USGS is
establishing a higher, “state of the
art” standard. The USGS
leadership in this technical area is
to be commended.
Technology – Flow Measurements

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DUCK

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8th Technical Committee Findings
The 8th TC has determined, that the LMDA (WYs 2010, 2011, 2012, 2013, 2014,
and 2015) are in compliance with the 1980 Modified Decree, with respect to
the “best current engineering practice and scientific knowledge”.
• The 8th TC is in general agreement with the findings and recommendations made
by the Seventh Technical Committee. Actions have been taken in most cases to
comply with the recommendations, and progress has been made since the
Seventh Technical Committee recommendations were made.
• From the standpoint of “best current engineering practice and scientific
knowledge”, the progress of the LMDA has been significant in a number of
engineering/scientific areas: 1) hydrologic and hydraulic modeling and 2) flow
measurements. The acoustical flow measurement technology has not only met
the “best current engineering practice and scientific knowledge” but
contributed through their pioneering efforts in the Chicago Sanitary and Ship
Canal (CSSC) flow monitoring to the developing of cutting-edge protocols
supported by the most advanced measurements technologies.

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Questions and Comments
8th Technical Committee
Dr. Muste
Dr. Melching
Dr. Espey

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