United States
Environmental Protection
Agency
Region 5
230 South Dearborn Street
Chicago, Illinois 60604
March 1988
Municipal Facilities Branch - Technical Support Section
Metropolitan
Sanitary District
Of Greater Chicago
Tunnel and
Reservoir Plan
Special Evaluation
Project
Interim
Report
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Metropolitan Sanitary District
of
Greater Chicago
Tunnel and Reservoir Plan
Special Evaluation Project
Interim Report
U.S. Environmental Protection Agency
Region V
Water Division
March 1988
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TABLE OF CONTENTS
Chapter
2
3
4
5
6
7
8
9
Number
1
2
Description Page(s)
Table of Contents i
List of Tables ii
List of Figures iii
Acknowledgements 1
Purpose and Scope 2-3
Findings
Introduction and Background 4-11
Upper Des Plaines Tunnel and 12 - 19
Reservoir Plan (TARP) System
Mainstream TARP System 20 - 36
Calumet TARP System 37 - 45
Groundwater Monitoring 46 - 60
U.S. Army Corps of Engineers Studies 61 - 63
Water Quality Baseline Report 64
Summary 65 - 67
APPENDICES
Description
Bibliography
USEPA comments to the U.S. Army Corps of Engineers on
General Design Memorandum Report and CoE response.
Plan of Study for Metropolitan Sanitary District of
Greater Chicago Tunnel and Reservoir Plan Special
Evaluation Project
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LIST OF TABLES
Table
Number Description Page(s)
1 Federally Funded TARP Projects 10
2 Summary of O'Hare WRP Flow Data 17
3 Final Effluent Data for O'Hare WRP 18
4 Operation and Maintenance Costs 19
Upper Des Plaines TARP System
5 Mainstream TARP Segments 23
6 Mainstream TARP Flow/Load Expectations 24
7 Mainstream TARP - Precipitation and Flow Data 25
8 Final Effluent Data for WSWTW 26
9 Mainstream TARP - Ungated Locations 33
10 Calumet Tunnel System
(Crawford Avenue to Pumping Station) 39
Contracts 73-287-2H and 73-273-2H
41
11 Calumet Effluent Data
12 Calumet TARP Pumping 42
13 Calumet TARP Discharge Quality 43
14 Operation and Maintenance Costs 45
Calumet TARP System
ii
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LIST OF FIGURES
Figure
Number Description Page(s)
1 Tunnel and Reservoir Plan 8
Phase I and II Map
2 Upper Des Plaines System of TARP 13
3 Mainstream System of TARP 21
4 Typical Combined Sewer Sewer Outfall 30
Connection to Mainstream Tunnel
5 Typical Interceptor Connection to 32
Mainstream Tunnel
6 Mainstream Tunnel Volume Stored and Rainfall 36
7 Calumet System of TARP 38
8 Mainstream System of TARP Monitoring Wells 49
9 TARP Upper Des Plaines Monitoring Wells 52
10 TARP Calumet System Monitoring Wells 55
11 Comparison of Tunnel and QC-2 Water Levels 56
12 QC-2 Monitoring Well Data 57
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ACKNOWLEDGEMENTS
Special acknowledgement is made to Mr. Bill Macaitis, Assistant Chief
Engineer and the other numerous representatives of the Metropolitan
Sanitary District of Greater Chicago for their assistance in furnishing
documents, arranging and participating in on-site inspections and by
their participation at the steering committee meetings. Acknowledgement
is also made to Messrs. Toby Frevert and Ed Marek of the Illinois Environ-
mental Protection Agency and the U.S. Army Corps of Engineers for their
participation in this Special Evaluation Project.
This document was researched, compiled and authored by the following
individuals:
Valdis A. Aistars
Ernesto R. Lopez
Russell J. Martin
William A. Melville
Thomas L. Poy
Charles J. Pycha
David R. Siebert
Assistance, contributions and general review of this document were pro-
vided- by the following individuals:
Charles H. Sutfin, Director, Water Division
Dale S. Bryson, Deputy Director, Water Division
Todd A. Cayer, Chief, Municipal Facilities Branch
Jerri-Anne Garl, Chief, Office of Ground Water
Eugene I. Chaiken, Chief, Technical Support Section
Harlan D. Hirt, Chief, Environmental Planning Section
Richard J. Zdanowicz, Chief, Design/Construction Unit
Noel W. Kohl, Chief, Monitoring and Standards Unit
Roger K. Coppock, Chief, Special Projects Team
James E. Luey, Environmental Protection Specialist
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CHAPTER 1
PURPOSE AND SCOPE
One of the Initiatives utilized by the USEPA Region V Water Division Office
for monitoring and evaluating the effectiveness of the many programs and
projects which are under the purview of the Water Division is the use of
special evaluation projects. These special evaluation projects have been
utilized in the past to review elements of the Construction Grants Program
activities and also have examined the effectiveness, efficiencies, and
costs of various technologies.
Since 1975, the USEPA has provided over $944 million in Clean Water Act
Construction Grant funds to assist the Metropolitan Sanitary District of
Greater Chicago (MSDGC) in the construction of the largest combined sewer
overflow project in the Nation. Inasmuch as over half of the segments of
the Tunnel and Reservoir Plan (TARP) are complete and operational, the
USEPA Region V Water Division decided that it was appropriate to perform a
special evaluation project (SEP) on TARP. This SEP provides an analysis of
the constructed portion of TARP Phase I.
Specifically, SEP objectives were directed:
*
1. To compile information on operation and design data pertaining to
conditions prior to construction of operational elements of TARP Phase I;
2. To compile information on conditions pertaining to the actual construction
and operational data of operational elements of TARP Phase I including
effects on ground water quality;
3. To compare and contrast the "design" and "operational" data; and,
4. To evaluate the effect of operation of the TARP Mainstream system on
indicators of water quality. The task of collection and analysis of the
information in the water quality portion of the study was extended to
allow time for the system to stabilize (particularly with respect to
existing benthic deposits) and respond to reduced input loads. For this
reason, the interim report presents a water quality baseline chapter.
(NOTE: The chapter containing the water quality baseline data is under
development and is not included in the March 1988 edition of this report).
A subsequent report will address the water quality indicators after the
water quality system is stabilized. This subsequent report is presently
projected for completion in the Plan of Study for Federal Fiscal Year
1990.
The evaluation of TARP Phase I operational elements is separated into three
areas, with the examination focusing on different aspects of the projects
due to their unique characteristics.
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- Upper Des Plaines TARP
0 Historical aspects of the operation of the Upper Des Plaines TARP system,
focusing on correlations to current portions of other elements of the
system that are now operational.
0 Major construction, maintenance and operational characteristics.
Mainstream TARP (Focus of Region V effort)
0 Operational characteristics in relation to design parameters (Effective-
ness of wastewater capture).
0 Effects of operation on WWTP. (Considering ongoing WWTP construction.)
0 Major construction, maintenance and operational characteristics.
0 Water quality indicators will be assessed in an area that encompasses
portions of the Chicago waterways downstream and adjacent to the Main-
stream System, e.g., Northshore Channel, North Branch Chicago River,
Chicago River, South Branch Chicago River, Sanitary and Ship Canal, and
the Lower Des Plaines River. Only an assessment and cataloging of avail-
able baseline data will be presented in the interim report. (NOTE:The
chapter containing the water quality baseline data is under development
and is not included in the March 1988 edition of this report.)
0 The effects of TARP operation on Lake Michigan will also be assessed
within the context of backflow events and beach closures in the vicinity
of the Wilmette and Chicago Lock and Dams. (Note: The chapter which
discusses these effects is under development and is not included in the
March 1988 edition of this report.)
Calumet TARP
0 Major construction, maintenance and operational characteristics.
This study was conducted in accordance with the revised Plan of Study which
is attached in Appendix 3.
The findings of USEPA's examination of the constructed portion of TARP are
described in Chapters 2-8, with the more noteworthy items highlighted in
Chapter 9.
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CHAPTER 2
INTRODUCTION AND BACKGROUND
HISTORICAL BACKGROUND
The Chicago area has a long history of building tunnels which started with
water supply tunnels in 1867. The first water tunnel, placed in operation
in March of that year, was a five foot diameter brick tunnel, built in
clay, approximately 60 feet below lake level, and extended two miles into
Lake Michigan to the Two Mile Crib intake. It was designed to supply lake
water to the City of Chicago's first pumping station. As the City grew and
its water works system expanded, additional tunnels were built to new pump-
ing stations. During the construction of these tunne-ls, many difficulties
were experienced due to poor soil conditions. In an attempt to avoid the
difficulties encountered, City engineers resolved that, wherever feasible,
future tunnels would be constructed in rock. The first.tunnel built in
rock was initiated in 1906 and completed in 1911. Other tunnels were
subsequently constructed. The depth of these water tunnels varied from 102
to 148 feet for the land portion and was generally 160 feet below Lake
level. Today, there are 65 miles of water tunnels in service and of these,
57 miles are constructed in rock.
Concern over water pollution and public health problems began with the
earliest Chicagoans who depended on shallow wells for their water supply ,
and outdoor privies as a means for disposing of their personal wastes.
Pollution or contamination of their drinking water occurred when the water
table was high and the privies leached into the wells. As a result, typhoid
fever and amoebic dysentery were prevalent. To fight these plagues, drink-
ing water dipped from Lake Michigan was peddled from door to door in horse-
drawn carts. In time, these carts were replaced by water pipes and tunnels
as discussed above. Meanwhile, sewers were laid to drain the swamp and
collect excess water. The privies drained into these sewers which emptied
into the river and thence to the Lake. On August 2 to 3, 1885, a cloudburst
occurred which dumped more than six inches of rain on Chicago streets
sweeping the streets clean of debris, dirt and dust. The pollution result-
ing from this storm reached beyond the pipes that drew in water from the
Lake bottom for the City's drinking water needs, thereby contaminating it.
The epidemic that followed claimed the lives of 90,000 people of the
750,000 existing population. Within a few days of the storm, a commission
was appointed to protect the City against recurrence of the tragedy. By
July 1, 1889, a plan was drawn to decisively and permanently reverse the
flows of the Chicago and Calumet Rivers away from the Lake and into the
Des Plaines River. A canal was dug which not only carried the waters of
the two rivers, but also drained a network of intercepting pipes that were
placed to catch the burden of the sewers before it reached Lake Michigan.
On August 15 of the same year, a petition to organize a Sanitary District
of Chicago (SDC) was submitted to the Illinois Legislature, and on
November 5, the voters overwhelmingly approved the proposal.
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The SDC then proceeded to construct the canal system. In 1900, a suit
"was filed by the State of Missouri, claiming that typhoid bacteria from
the Chicago area was contaminating its water supply. Under the direction
of a Master appointed by the Supreme Court, 107 barrels of a less deadly
strain of typhoid bacilli were dumped into the Sanitary and Ship Canal
at Chicago. In the following weeks, none of the bacilli was found at
St. Louis and Missouri lost the case. The United States (U.S.) filed
suit against SDC to 1imit diversion of Lake water to 4,167 cubic feet per
second (cfs). The channels were designed for a 10,000 cfs flow. The
case was decided in favor of U.S. in 1925. As a result of this decision
and in order not to degrade the water quality of the waterways, the
District constructed its major treatment facilities. In 1939, a Supreme
Court Decision further limited the diversion to 1500 cfs plus domestic
pumpage. Additional litigation initiated in 1961 by the State of
Illinois resulted in a diversion limit of 3,200 cfs including domestic
pumpage. In January 1977, the State of Illinois, Department of Trans-
portation-Division of Water Resources ordered the allocation of Lake water
to eligible applicants. Under this order, the District was allocated
307 cfs of water for lockages, leakages, and navigational makeup. This
order also transferred the responsibility of discretionary diversion and
storm runoff from the District to the State. On December 1, 1980, the
Supreme Court amended its 1967 decree allowing Illinois to average within
certain limits, the diversion over a period of 40 years instead of 5 years
as originally order'ed, while keeping the 3,200 cfs limit unchanged. To
utilize the flexibility of the long-term averaging clause, Illinois issued
a Water Allocation Order LMO 80-4 to municipalities and subdivisions,
limiting the usage of water by the District for lockages, leakages, and
navigational purpose to 255 cfs.
The reduction of water pollution of the Lake also involved the construction
of intercepting sewers. The first sewers in Chicago were constructed in
1843. By 1890, the City's sewer system included 700 miles of sewer serving
an area of 170 square miles and a population of 1.1 million people. These
sewers were constructed of brick laid in concentric rings and have diameters
ranging from 24 inches to 20 feet. Beginning in the 1890's, the increase in
the construction of buildings, hard pavements, and sidewalks as well as
extending existing sewer lines beyond their original limits caused greater
storm runoff than was allowed for in the original sewer designs. This
resulted in the flooding of basements at the end of the last century. By
1907, the basic sewer system was completed, and Chicago became the first
Great Lakes city to stop using Lake Michigan as a receptor of its domestic
sewage. Subsequent and continuous construction that has taken place before
and after World War II caused an even greater increase in imperviousness
and stormwater runoff, resulting in a construction program to increase
sewer capacity within the City. After 1930, sewer technology changed in
such a way that brick use declined. Sewers with diameters under 30 inches
were constructed of tile pipes while those over 30 inches used reinforced
concrete. In 1947, construction began on an area-wide system of large com-
bined relief sewers to supplement existing major main sewers as well as
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provide every neighborhood with a sewer outlet capable of handling a 5-year
frequency storm. Presently, Chicago's sewer system consists of approximately
4,300 miles of sewers covering a land area of 228 square miles.
The Sanitary District of Chicago, now known as the Metropolitan Sanitary
District of Greater Chicago (MSDGC), was organized under the Illinois
Revised Statutes, Chapter 42, Section 320 to remove obstructions in the Des
Plaines and Illinois Rivers. The Revised Statutes authorize MSDGC to treat
wastewater, either totally or partially, from any municipality within its
designated jurisdiction, as well as to construct, own and operate all waste-
water treatment and collection works located within its boundaries. Over
the years, the MSDGC grew by annexations until today, its service area is
approximately 872 square miles. Approximately 375 square miles are served
by combined sewer systems in which wastewater or sewage collected in local
sewer systems is conveyed to treatment works. These systems serve 120
municipalities which have a total population of 5.5 million. MSDGC con-
trols and operates 70.5 miles of navigable canals, and owns and operates
seven wastewater treatment works, and approximately 524 miles of inter-
cepting sewers. The major treatment works (Uest-Southwest, North Side,
Calumet) have a combined secondary capacity of 1753 MGD. The O'Hare,
John E. Egan, and Hanover Park Water Reclamation Plants and the Lemont
Sewage Treatment Plant have capacities of 72 MGD, 30 MGD, 12 MGD, and 1.6
MGD, respectively.
DEVELOPMENT OF THE TUNNEL AND RESERVOIR PLAN (TARP)
The growth of the District's service area and multiplication of captured
rainwater volume had exceeded the sewer system's capac.ity. On an average
of 100 times a year, combined sewers overflowed and surged into the
Chicago and Calumet Rivers at 640 different locations prior to the opera-
tion of TARP. Basement back-ups also occurred. In addition, the combined
sewer overflows contributed to poor water quality of the Chicago and Des
Plaines River systems and even the Illinois River. Also in the last 30
years, the flood gates of the Chicago and Calumet Rivers have been opened
35 times to prevent the overflowing of their banks, resulting in City
beaches being closed to swimmers at times.
Many plans to resolve the Chicago area's flooding and water pollution problems
were developed during the 1950's and 1960's by concerned government agencies,
local organizations and individuals. At first, the plans focused primarily on
the flood control problem. However, as water quality conditions in the area
worsened, more emphasis was placed on controlling water pollution. A total of
twenty-three plans was formulated, and many were considered and evaluated in
detail by the Flood Control Coordinating Committee (FCCC). The FCCC was organ-
ized soon after a 1957 rainstorm which caused extensive flooding damage in
the Chicago metropolitan area. It was to study various alternatives advocated
to solve flooding problems in the area. The Committee members could not
reach an agreement and the FCCC was eventually disbanded. In November 1970,
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it was reactivated and consisted of representatives from the State of Illinois,
•Cook County, MSDGC and City of Chicago. The new Committee began to consider,
screen and evaluate various alternative plans.
In screening the alternative plans, the FCCC established overall flood and
pollution control objectives which provided a basis for evaluating alternative
plans. Acceptance of a plan was dependent upon whether it would prevent all
backflows to Lake Michigan to protect water supply resources, reduce pollutant
discharges caused by combined sewer overflows, and reduce flooding in the
combined sewer and downstream areas.
Initial screening by the FCCC resulted in six alternatives being eliminated
from further consideration and modifications being made to the remaining 17.
These modifications consisted of a combination of different storage capacities
and waterway improvement actions. The resulting modifications yielded 51
alternative subsystem plans or subplans to be evaluated by the FCCC. The next
screening phase identified eight principal parameters defined by the FCCC,
namely: capital costs (1972 dollars), estimated annual operating and mainte-
nance costs (1972), project benefits, land acquisition acreage, underground
easement requirements, resident and business relocations, construction impacts,
and operation impacts. In order to evaluate the modified alternatives, the
FCCC organized a technical advisory committee. The committee issued an interim
report recommending a 50,000 acre-feet storage capacity. Upon reviewing the
report, the FCCC concluded that the flood and pollution plan should be in the
form of one of the four Chicago Underflow plans developed or a combination of
these plans, along with the recommended storage level.
In August 1972, the FCCC issued a report which recommended consolidating
favorable features of the four Underflow plans into the Tunnel and Reservoir
Plan (TARP). What followed was a further development and refinement of TARP
and an evaluation of TARP with five selected alternatives including "no
action." The FCCC concluded that: (1) very few negative impacts are expected
for any of the alternatives incorporating conveyance tunnels when compared to
the "no action" alternative; (2) construction impacts of all plans on the
environment are expected to be short-term and localized; and, (3) the benefi-
cial impacts far exceed the adverse impacts. The report stated that TARP was
selected as the most suitable plan to solve the flood and pollution problems
at the lowest cost and with the minimum adverse environmental impact.
TARP, as shown in Figure 1, consists of 131.1 miles of conveyance tunnels,
three reservoirs, sewage treatment facilities, pumping stations, drop shafts,
and collecting structures. It has four main tunnel systems: Mainstream,
Calumet, Lower Des Plaines, and Upper Des Plaines. Other than the Mainstream -
Lower Des Plaines tunnel systems which are tied together, each system is a
complete, independent operating unit with collection, storage, conveyance,
and treatment capabilities.
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FIGURE 1
CD
LYONS
PHASE 1 TUNNEL
PHASE 2 TUNNEL
COMPLETED PHASE \ TUNNEL
PREVIOUSLY COMPLETED TUNNEL
PHASE 2 STORAGE RESERVOIR
TREATMENT WORKS
PHASE 2 ON-LINE RESERVOIR
PHASE \ PUMPING STATION
PHASE 2 PUMPING STATION
3210
Source:
THORNTON l~' S'
LANSING a
3 ilLES
CHICAGOLAND UNDERFLO* PLAN
PHASE I GDM
TUNNEL AND RESERVOIR PLAN
PHASES 1 AND 2
CORPS OF ENGINEERS CHICAGO DISTRICT
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GRANT-FUNDING FOR TARP
When completed, TARP will collect, transport and store the combined sewer
overflows for the MSDGC service area. It will serve the dual purpose of
pollution abatement and flood control. Pollution abatement will result from
capturing and storing the polluted overflows until the MSDGC's wastewater
treatment facilities can provide full secondary and advanced treatment.
Flood control will be provided simultaneously due to TARP providing an alter-
native intercepting system capable of accepting combined sewer flows until
capacity is reached. Also, overbank flooding will be reduced since combined
sewer overflows will not enter the waterways.
At the request of MSDGC, the U.S. EPA examined the funding implications and
separated those portions of TARP whose primary function was pollution abate-
ment and are presently known as Phase I from the Phase II portions which
primarily relate to flood control. Table 1 identifies the federally funded
projects of TARP Phase I. It should be noted that not all segments of TARP
- Phase I have been constructed. The Lower Des Plaines TARP segment; the
North Branch of the Chicago River segment of the Mainstream system; and 140th
Street leg, Torrence Avenue leg, Indiana & Markham Avenue leg, and the Little
Calumet legs have not yet been funded.
ENVIRONMENTAL IMPACT STATEMENTS
Environmental impact statements (EIS) are required to be prepared by all
Federal agencies for those actions significantly affecting the quality of
the human environment. Since the TARP project was identified as being an
action which could have a significant impact to the human environment,
EIS's were prepared for the Mainstream (with the exception of the Addison
to Wilmette Harbor segment), Upper Des Plaines (O'Hare), Calumet, and Lower
Des Plaines tunnel systems. These statements described the conditions as
they existed at the time of preparation in the natural and man-made environ-
ments, provided a summary of alternatives proposed for solving combined
sewer overflows, described in detail the selected alternative, assessed the
benefits and adverse effects of the construction and operation of the tunnel
systems on greater Chicago's natural and man-made environments, and presented
the conclusions reached and recommendations. The following is a summariza-
tion of the EIS findings, conclusions and recommendations considering ground-
water, spoil disposal, and the general effects of construction (including
blasting):
0 GROUNDWATER - The inflow rate of groundwater for the TARP tunnel systems
was estimated to be an average of approximately 0.5 MGD per mile of
tunnel. This rate is sufficient to lower the piezometric or hydraulic
pressure level of the upper aquifer. The most effective method of
reducing this type of infiltration is grouting, and such a program has
been incorporated in TARP. Additionally, under surcharged conditions,
exfiltration could result in adverse impacts on the groundwater quality
of the upper aquifer. Observation wells to monitor grouting integrity
during operation are necessary along the entire tunnel alignment.
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TABLE 1 FEDERALLY FUNDED TARP PROJECTS
U.S. EPA
GRANT
NO. C17
5322 01
5322 03
5111 01
5321 01
5321 02
5321 04
5321 05
5321 06
5321 07
5321 08
5321 09
5321 20
5321 21
5321 22
5297 04
5365 01
5365 02
5365 20
DESCRIPTION
UPPER DES PLAINES (O'HARE)
TARP TUNNELS 20, 20B, 20C &
21 AND DROP SHAFTS
TUNNEL 20 A AND CONNECTING
STRUCTURES
O'HARE MRP PUMPING STATION
DATE OF
ORIGINAL
AWARD
06/23/75
09/27/77
05/23/75
MAINSTREAM
TARP TUNNELS
ADDISON ST. TO WILMETTE HARBOR
TARP CONNECTING STRUCTURES
ADDISON ST. TO WILMETTE HARBOR
TARP TUNNELS, DROP SHAFTS & CON.
STRUCTURES: OGDEN AVE. TO ADDISON ST.
TARP TUNNELS, DROP SHAFTS & CON.
STRUCTURES; ROOSEVELT RD. TO OGDEN AVE.
TARP TUNNELS, DROP SHAFTS & CON.
STRUCTURES; DAMEN AVE. TO ROOSEVELT
TARP TUNNELS, DROP SHAFTS & CON.
STRUCTURES; CENTRAL AVE. TO DAMEN AVE.
TARP CONNECTING STRUCTURES
59TH STREET TO CENTRAL AVENUE
TARP TUNNELS & DROP SHAFTS
59TH STREET TO CENTRAL AVENUE
TARP PUMPING STATION - PART I:
PUMPING STATION
TARP PUMPING STATION - PART II:
DISCHARGE & BRANCH TUNNELS
TARP PUMPING STATION - PART III:
INTAKE & TRANSFER TUNNELS
TARP TUNNELS, DROP SHAFTS, & CON.
STRUCTURES; WEST LEG - 13A EXT.
CALUMET
TARP TUNNELS & DROP SHAFTS; CRAWFORD
AVE. TO TARP PUMPING STATION
TARP CONNECTING STRUCTURES; CRAWFORD
AVENUE TO TARP PUMPING STATION
TARP PUMPING STATION
06/30/75
06/30/75
07/01/76
07/01/76
07/01/76
06/23/76
06/30/78
06/23/76
03/26/79
09/29/78
09/29/78
09/21/84
01/31/77
09/29/78
09/29/78
DATE OF
CONSTRUCTION
COMPLETION
09/28/80
05/28/81
12/82
SUBTOTAL
01/15/82
09/28/82
08/15/83
10/01/83
06/15/84
09/16/83
12/10/82
02/15/83
01/30/85
08/04/84
08/15/83
T 02/02/88
CURRENT -
GRANT AMOUNT
($)
47,977,568
3,953,535
15,000,000
66,931,103
49,232,475
67,854,975
74,476,997
85,659,225
92,718,110
73,450,573
22,658,644
64,338,692
138,943,575
50,258,534
20,175,989
16,096,050
SUBTOTAL
10/01/82
10/15/83
10/85
755,863,839
58,093,145
12,589,509
47,160,900
SUBTOTAL
GRAND TOTAL
117,843,554
944,122,396
10
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Should pollutants be detected in the wells, mitigative measures were to
be implemented to protect the upper aquifer including the groundwater
recharge system;
SPOIL DISPOSAL - It is the policy of the MSDGC to place on the construc-
tion contractors the responsibility of disposing of material excavated
from each Phase I tunnel system with the exception of a relatively small
amount of material retained by the Cook County Forest Preserve District.
MSDGC's expectation was that the contractors will either find markets
for the excavated materials or would utilize suitable, environmentally
acceptable waste disposal sites. Approximately 17,620,000 bulk cubic
yards of rock and soil was estimated to be produced as a result of the
excavation. The suitability of the rock excavated from the tunnels was
limited to low grade commercial uses and for fill. This is due to the
fines, angular shape of the cutrock, shale and other constituent content
in the rock. The environmental impacts associated with the disposal of
the spoil-depend on the availability of landfill disposal sites. The
impacts on the environment include exhaust and dust emissions to the
atmosphere from truck traffic and noise, the reduction of space at the
disposal site for municipal refuse or other solid waste, and the shorten-
ing of the landfill's life expectancy. However, due to the stable
nature of the rock spoil, the sort of environmental problems (methane
gas production, leachate contamination of groundwater or surface waters)
associated with landfilling of municipal refuse were not expected.
Some temporary storage included the McCook Quarry, Birsch Brick Yard,
and Paschen Construction Company yard located on Archer Avenue; and,
GENERAL EFFECTS OF CONSTRUCTION: The construction of the tunnel systems
was expected to result in temporary public annoyance and inconvenience
from the cumulative effects of noise, handling of construction debris,
vibration from blasting, disruption of vehicular and pedestrian traffic,
and glare from the illumination of construction areas at night. Specifi-
cally, construction of access and drop shafts would require some blasting
operations. These operations would create noise and vibrations, increase
the sensitivity of people to the duration of the project, and would raise
concern over possible property damages. A well-planned operation could
allay many of the concerns the public may have over the effects of blast-
ing. MSDGC could make certain that no structural damage occurs by placing
blasting limitations in the project's construction specifications.
Further reductions in the allowable limits could be made to make blasting
less noticeable. Steps could be taken to keep the public sufficiently
informed so that observers of the blasting will have no cause for alarm
and would be willing to accept some minor irritation in return for the
benefits which the project can bring to the community.
As a result of the EIS's findings and conclusions, a groundwater monitoring
program was implemented for all TARP systems. Similarly, MSDGC was required
to submit a report and develop detailed plans for the utilization or disposal
of rock spoil for the Mainstream and Calumet systems. MSDGC has also limited
blasting to levels lower than those set by the U.S. Department of Interior -
Bureau of Mines.
11
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CHAPTER 3
UPPER DES PLAINES TARP SYSTEM
INTRODUCTION
Due to development of the northwest area of the MSDGC jurisdiction in the early.
1960's, MSDGC investigated possible alternatives to provide relief to the
existing sewers. The initial recommendation was to construct an intercepting
sewer system to convey all of the sewage to the West-Southwest Treatment Works
in Stickney. However, the cost and magnitude of the project would have required
such implementation time as to necessitate temporary treatment plants in the
northwest area, making this alternative not cost-effective. As a result, the
northwest area was divided into four facility areas corresponding to the exist-
ing drainage basins. One of these is the Upper Des Plaines (O'Hare) facility
area.
The Upper Des Plaines facility area is located in the northwest portion of Cook
County. It has a drainage area of 88.7 square miles, 13.7 square miles being
combined sewer area with 119 outfalls. Facility planning in the mid-19701s for
this area, which was originally tributary to the MSDGC North Side Sewage Treat-
ment Works, resulted in the selection of a plan that included a regional treat-
ment facility and a tunnel system which is part of MSDGC's TARP.
Along with the diversion of sanitary sewage flow from existing intercepting
sewers, the Upper Des Plaines TARP captures combined sewer overflows (CSO's).
These flows are treated at the O'Hare Water Reclamation Plant (WRP), designed
specifically to include capacity for treating stored combined sewer overflows.
CONSTRUCTION
The Upper Des Plaines TARP tunnel system consisted of four construction con-
tracts. The tunnel system includes 6.6 miles of rock tunnels, 8 drop shafts,
and 18 connecting structures for a phase I storage capacity of 212.8 acre-feet
(see Figure 2). The four construction projects are as follows:
The Upper Des Plaines No. 20 consisted of 22,000 linear feet of 20 foot diameter
tunnels at depths ranging from 130 to 180 feet and 5 drop shafts. This tunnel
section can convey 489 cubic feet per second (cfs) of peak sanitary flow to the
treatment plant. With an average design dry weather flow of 204 cfs, these
tunnels provide some storage for CSO's from smaller storms.
The Upper Des Plaines No. 20A consisted of special connecting structures and
lateral sewers to control and divert flow from existing intercepting sewers and
CSO outfalls to the drop shafts and tunnels in the system.
The Upper Des Plaines No. 20B consisted of 6000 linear feet of 5 foot diameter
earth tunnels to divert sanitary sewage flows from the northern and western
portions of the facility area to the O'Hare WRP. These tunnels have a capacity
to divert 86 cfs of peak sanitary flow that would have been conveyed to the
North Side treatment plant.
12
-------
FIGURE 2: UPPER DES PLAINES SYSTEM OF TARP
BUFFALO GROVE
lake County
Cook County
N
WHEELING
ARLINGTON
HEIGHTS
UPPER DES PLAINES 21
CONTRACT 73-320-2S
\ ROLLING
MEADOWS
Central
UPPER DES PLAINES 20
Rock Tunnels & Drop Shafts
CONTRACT 73-317-2S
IPPER DES PLAINES 20C
ONTRACT 69-307-2S
i—,
Devon
ELK GROVE
UPPER DES PLAINES 20B
CONTRACT 73-319-25
UPPER DES PLAINES 20A
Connections & Laterals
CONTRACT 73-318-2S
MT. PROSPECT
UPPER DES PLAINES
STORAGE RESERVOIR
Source:
THE METROPOLITAN SANITARY DISTRICT
OF GREATER CHICAGO
ENGINEERING DEPARTMENT
F.J.K.
13
-------
The Upper Des Plaines No. 21 consisted of 11,200 linear feet of 16 foot diameter
deep rock tunnels, 2,000 linear feet of 9 foot diameter deep rock tunnels, and
3 drop shafts. These tunnels have a capacity to convey 266 cfs of peak sanitary
flow. With an average design dry weather flow of 102 cfs, there is some capacity
for storage of CSO's.
At the same time the collection system was constructed, the O'Hare WRP was built.
It is designed to operate as a two-stage activated sludge process with tertiary
filtration. The first phase of plant construction, now completed, is designed
to treat a flow of 72 MGD. Space and engineering design considerations have
been provided for future construction to expand plant treatment capacity to 96
MGD. As previously mentioned, the treatment plant design includes the capacity
for treating stored combined sewer overflows in the peaking requirements. The
O'Hare WRP became operational in May 1980. Because of energy considerations,
operational changes were made in October 1981. The plant presently provides
preliminary and single stage nitrification treatment with chlorination.
Two problems were encountered during the start up of the Upper Des Plaines TARP.
During the initial dewatering of the system, a vibration problem was encountered.
The discharge pipe from the pumping station caused several floors of the pump
station to vibrate. This vibration of the floors was caused by harmonic motion
and misalignment of the pipe. The vibration was remedied by realigning and
adding extra support to the discharge pipe. The other problem that occurred
during the start up of the system was sewage odors coming from the drop shafts.
Under normal operation, water flow through the tunnel system causes air to move
in the direction of the flow. However, under certain weather conditions, air
currents are expelled from the drop shafts. This problem was solved by install-
ing louvers to control the air flow in the system. The air is directed toward
the main construction shaft near the treatment plant, where the air is deodorized
with ozone and expelled. The experience gained from the handling of this odor
problem has been used in both the Mainstream and the Lower Des Plaines systems.
Louvers have been installed at potentially sensitive urban drop shaft locations
in the Mainstream system and are designed into many drop shafts in the Lower
Des Plaines TARP.
OPERATION
The operation of the Upper Des Plaines TARP is quite flexible. The system has
been designed and operated so that sanitary sewage flows into the rock tunnels
unrestricted. Combined sewage flow is regulated by control structures on the
combined sewer outfalls. The present operation of the system is geared to
prevent surcharging of the sanitary sewers. When the water level in the rock
tunnels reaches 25 feet above the tunnel invert (60% full), the sluice gates
may be closed or throttled down to limit the tunnel inflow to unrestricted
separate sanitary sewage flow and dry weather equivalent combined sewer flow.
This restriction of the inflow from the combined sewers causes overflows into
the waterways. When the tunnel water level is 20 feet above the tunnel invert
and falling, the sluice gates are reopened.
14
-------
An additional amount of flexibility is gained because of the fact that the
intercepting sewer of the drainage basin had originally been designed to convey
flows to the North Side treatment plant. Two control structures put in to
isolate flows from the North Side plant contain gates that may be opened to
allow flows through. The flows that can be diverted to the North Side plant
are sanitary and/or combined. The system of control structures, which regulate
the overflow and/or diversion of flows, is operated by computer at the O'Hare
WRP. Information on water levels in the tunnel system, water levels at the
gates, gate positions, and other necessary information is available at the plant
to allow for decision making by the computer or by the operator in the event of
failure of the automatic control system. In the event of power failure, the
sluice gates are equipped with hydraulic accumulator devices so they can be
closed.
One of the important factors in determining the available tunnel capacity is
the dewatering done at the O'Hare WRP. The primary objectives for the pumping
procedures are:
(1) maximize the use of tunnel storage volume;
(2) maximize the capture and treatment of flows;
(3) minimize solids deposits in the tunnel by daily scouring; and,
(4) minimize electrical costs for pumping.
Based on these objectives, the pumping rate is dependent upon the time of day
and the weather conditions. During dry weather, between 9 a.m. and 10 p.m.
when electric costs are at their peak, pumping is limited to 24 MGD until the
tunnel level reaches 8-feet. Then the rate is increased up to a maximum of
40 MGD or the third highest value that was used during the current billing
period to maintain the 8-foot tunnel level. During dry weather, off peak hours
(including weekends and holidays), the tunnels are pumped to draw down the
water level as low as possible to promote solids removal. During wet weather,
peak periods, flow is limited to 24 MGD until the tunnel level reaches 8 feet.
When above the 8 foot level, the pumping is increased incrementally as follows:
10 feet and rising, 60 MGD; 12 feet and rising, 75 MGD; 14 feet and rising,
90 MGD; 16 feet and rising, 120 MGD; 18 feet and rising, 140 MGD. During wet
weather, off-peak periods, pumping is increased at a greater rate as follows:
8 feet and rising, 75 MGD; 10 feet and rising, 90 MGD; 12 feet and rising,
120 MGD; 14 feet and rising, 140 MGD. Flows may be increased at a faster rate
as dictated by good judgement.
O'Hare WRP operating data from MSDGC's "Monthly Plant Operating Data" for the
period of June 1985 to December 1986 have been examined and the system appears
to be operating as designed. Tables 2 and 3 summarize this operating data.
For most of the significant rainfall events, there has been an associated
increase in the total flow into the treatment plant. Even though the plant
has a design capacity of 72 MGD, on 33 occasions flows greater than 72 MGD were
treated with no appreciable effect on effluent quality. For the rainfalls over
one inch, there have been noticeable decreases in the BOD and suspended solids
15
-------
concentration of the raw influent which would be expected with the dilution
caused by the stormwater captured by the tunnel system. Despite the increased
hydraulic loading, the treatment plant has performed well. There is a proposed
NPDES permit for the O'Hare WRP that would limit discharges to monthly averages
of 4 mg/1 and 5 mg/1 for BODs and total suspended solids, respectively. For
the time period mentioned above, 15 of the 19 months had monthly 8005 averages
of 2 mg/1 and 13 of the 19 months had monthly total suspended solids averages
of 2 mg/1. The highest monthly average for either parameter was 3 mg/1, still
under the permit limits. Also, the O'Hare WRP did not approach the proposed
daily maximum concentrations for 8005 or total suspended solids, 20 mg/1 and
24 mg/1, respectively. The highest daily values during these 19 months were
8 mg/1 for 8005 and 12 mg/1 for total suspended solids. The proposed NPDES
permit also limits discharges of ammonia nitrogen. From April to October, the
maximum daily discharge is 1.5 mg/1. From November to March, the ammonia
nitrogen discharges are limited to a monthly average of 4 mg/1. Over the
19-month period examined, none of the monthly averages exceeded the limit and
the daily maximum was only exceeded 3 times.
MAINTENANCE
The tunnels and sewers of the Upper Des Plaines TARP are made of materials that
the MSDGC feels are permanent in nature. Thus, with the exception of a minimum
amount of mechanical equipment, the TARP system is largely maintenance free,
requiring only periodic inspections for leaks and blockages. Drop shafts are
relatively maintenance free also, requiring an inspection every 1-2 years after
initiation of operation and then once every five.years afterwards. Control
structures are inspected at least once a month and after every rain storm. This
seems to be sufficient, as the normally monitored functions at the O'Hare WRP
control panel will indicate any problems that occur. Table 4 contains the
operating and maintenance costs for the Upper Des Plaines TARP system.
16
-------
TABLE 2
SUMMARY OF O'HARE WRP FLOW DATA
Total Monthly Plant
Flow (MG)
June 1985
July
August
September
October
November
December
January 1986
February
March
April
May
June
July
August
September
October
November
December
908.9
847.2
973.4
772.0
1109.2
1854.8
1323.50
849.5
943.6
1118.2
796.5
1104.7
1136.3
1213.9
886.1
1487.9
1543.70
927.40
985.20
Monthly
precip (in)
1.72
1.82
3.96
1.45
3.69
5.93
1.53
0.45
1.88
1.10
1.72
3.00
5.47
3.00
1.95
7.68
1.96
1.10
0.43
Average Daily Plant
Flow (MGD)
30.3
27.33
31.4
25.73
35.78
61.83
42.69
27.4
33.7
36.07
26.55
35.64
37.88
38.16
28.58
49.60
49.80
30.91
31.78
Source: Data from Monthly Plant Operating Data
17
-------
TABLE 3
FINAL EFFLUENT DATA FOR O'HARE WRP
June 1985
July
August
September
Occtober
November
December
January 1986
February
March
April
May
June
July
August
September
October
November
December
Avg
2
2
3
2
2
2
2
2
3
3
2
3
2
2
2
2
2
2
2
BOD5
Min
2
2
2
2
2
2
2
1
2
2
2
2
2
2
2
2
2
2
2
mg/1)
Max
3
5
6
2
3
3
3
4
8
7
3
7
5
8
2
5
2
2
2
Avg
2
2
3
2
2
2
2
2
3
3
2
3
2
2
2
2
2
1
1
FSS (mg/1)
Min 1 Max
1
1
1
1
1
1
1
1
2
•1
1
1
1
1
1
1
1
1
1
4
4
5
5
7
6
6
6
8
8
3
5
4
12
9
4
5
3
2
Avg
0.2
0.2
0.2
0.2
0.1
0.2
0.3
0.3
0.6
0.4
0.4
0.4
0.2
0.1
0.1
0.1
0.1
0.1
0.1
NH3-N
Min
0.1
0.0
0.0
0.0
0.0
0.1
0.1
0.1
0.1
0.1
0.1
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
mg/1)
Max
0.4
0.5
0.5
2.2
0.7
0.2
0.8
0.8
4.5
1.5
1.5
2.1
0.6
0.4
0.6
0.6
0.2
0.3
0.5
Source: Data from Monthly Plant Operating Data
18
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TABLE 4
OPERATION AND MAINTENANCE COSTS
Category
Operating Labor
Maintenance Labor
Parts and Material
Utilities
Electricity
Others
Overhead
Total
UPPER DES
1985
$ 82,720
132,370
61,740
630,000
28,600
46,390
PLAINES TARP SYSTEM
O&M Costs ($)
1986 (Proj.)
$ 85,970
80,190
41,500
713,000
28,800
49,280
1987 (Proj.)
$ 87,670
84,200
24,600
748,000
31,000
50,760
$981,820
$998,740
$1,026,230
Source: Data supplied by MSDGC
19
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CHAPTER 4
MAINSTREAM TARP SYSTEM
DESCRIPTION
The TARP Phase I Mainstream system, shown in Figure 3, involves a develop-
ment of tunnels, and a pumping station. The total length of tunnels is
40.3 miles. Construction of 31.2 miles of tunnels has been completed
including 116 drop shafts, 245 connecting structures, and a pumping station
which was placed in operation in mid-1985. The remaining segment of the
Mainstream system that has yet to be constructed is the North Branch -
Chicago River tunnel including connecting structures. Another 3.5 miles of
tunnel is currently under construction. This tunnel is an extension to a
previously constructed tunnel know as Tunnel 13A. The tunnels range in
size from 13 to 33 feet in diameter and were constructed approximately 240
to 300 feet below ground level. The tunnel, positioned predominately in
the Joliet formation and away from known fault zones, runs from Wilmette,
Illinois (located north of Chicago), south and southwest through Chicago to
McCook, Illinois. Combined sewage enters the tunnels through the drop
shafts and are carried to the new pumping station, where the flow is pumped
to MSDGC's West-Southwest Wastewater Treatment Works (WSWTW).
The pumping station is located in Hodgkins, Illinois and has the capacity
to dewater not only the constructed Mainstream tunnels, but also the pro-
posed Des Plaines system and North Branch - Chicago River segment of the
Mainstream system. The station provides space for eight pumps, six of
which are in operation. Four of the installed pumps have a total capacity
of 1,100 cubic feet per second (cfs) (710 M6D) at 330 feet of head, and
the remaining two can handle 490 cfs (316 MGD) at 150 feet of head. These
pumps are housed in twin pumping chambers 370 feet below ground and can
be used in four modes: pump from the tunnels to the treatment plant, pump
from the tunnels to the proposed reservoir, pump simultaneously from the
tunnels to the reservoir and treatment plant, and pump from the reservoir.
The first mode above is currently being used. Vertical single suction
pumps with vertical constant speed motors are used exclusively. Pump
casings are encased in concrete to support the heavy motors and control
vibrations. Pump motor cooling is by a four part ventilation system
serving two pumps each. Energy for the 85,000 hp of pumping (58,700 hp
high head and 10,970 hp low head) is supplied through two independent
substations tying into independent 138 KV transmission lines with switch-
over capability in case of failure of one system. In addition, batteries
and a diesel engine-driven generator are provided to supply highly critical
station loads in case of complete electrical failure.
In addition to the facilities building, the pumping station includes trash
and grit removal facilities, two cylindrical vent shaft buildings a gate
control building, a valve chamber access building, and two 90 foot surge
towers.
20
-------
FIGURE 3
EVANSTON
NILES
PARK
RIDGE
NORTH SIDE
TREATMENT
PLANT
LAWRENCE ST
OAK PARK
1-290
UNDER CONSTRUCTION
ROOSEVELT RD
LA GRANG
PARK
wsw CICERO
TREATMENT
PLANT
ca
WESTERN
SPRINGS
FOREST VIEW
MCCOOK
RESERVOIR
HOOGKINS
PUMPING
STATION
PHASE 1 TUNNEL
PHASE 2 TUNNEL
PHASE 1 TUNNEL COMPLETED
PREVIOUSLY COMPLETED TUNNEL
PHASE I PUMPING STATION
ON-LINE RESERVOIR
CHICAGOLANO UNDERFLOW PLAN
PHASE 1 COM
MAINSTREAM SYSTEM
OF TARP
CORPS OF ENGINEERS CHICAGO DISTRICT
21
-------
The performance of the Mainstream system is monitored and controlled by the
computer-equipped control center at the MSDGC's WSWTW. Conventional monitor-
ing and control serves not only as a back-up control system of Mainstream
TARP, but also controls the operation of the pumping station.
Table 5 identifies the various legs or segments of the Mainstream TARP
system and presents basic information including tunnel length and diameter,
number of drop shafts and connecting structures, and the tunnel storage
capacity. Included in this table is information on the 13A extension
segment which is still under construction. It excludes the North Branch -
Chicago River segment which is yet to be constructed. The next table,
Table 6, gives the percent of the combined sewer overflow BOD that each
segment eliminates within the area tributary to the particular segment.
Finally, precipitation and flow data for TARP and the. WSWTW are given in
Table 7. The source of the precipitation data in this table is the
National Weather Service, while the remaining data came from the monthly
plant operating reports as prepared by MSD6C. This table presents the
total flows at the WSWTW and in TARP as well as the precipitation data
for each month covering the period from October 1985 to December 1986.
The relationship between the precipitation and flow data is illustrated
in this table. Table 8 shows the final effluent data of the WSWTW for a
similar period. The table gives the monthly minimum, maximum, and average
discharge of 6005, total suspended solids and ammonia nitrogen for each
month in the referenced period of time.
GRANT HISTORY
The first Federal grant to be made on the Mainstream TARP system occurred
on June 30, 1975. This grant was made to construct the Wilmette to Addison
segment. During the next 3 years, ten additional grants were given to MSDGC
to construct the other segments of Mainstream TARP and the pumping station.
A total of twenty construction contracts were awarded. Construction of the
funded portions of the system was initiated in December 1975 and completed
in January 1985. The Mainstream TARP was dedicated in May 1985 and has
been in operation for over a year. All the Federal grants awarded are
physically completed (except 13A Ext.) and are scheduled for or are under
audit review prior to being closed out. The current total grant amount
(semi-final) for the system is $755,863,839. This figure may change due
to unresolved construction contractor claims, results of audits, and as-
sociated administrative and engineering costs. The U.S. Army Corps of
Engineers Quarterly Status of Construction Claims for December 1986, shows
that six of eleven Federal grants for Mainstream TARP listed in Table 1
have 21 unresolved contractor claims amounting to $26,952,477.
22
-------
TABLE 5: MAINSTREAM TARP SEGMENTS
MAINSTREAM
TARP SEGMENT
DISON ST. TO
LMETTE HARBOR
2-049-2H &
3-058-2H
DEN AVE. TO
DDISON ST.
5-123-2H &
5-118-2H
OSEVELT RD. TO
GDEN AVE.
5-124-2H &
5-119-2H
-MEN AVE. TO
.OOSEVELT RD.
5-124-2H &
5-120-2H
NTRAL AVE. TO
lAMEN AVENUE
'5-126-2H &
3-163-2H
>TH STREET TO
:ENTRAL AVENUE
'3-160-2H &
'3-163-2H
UNDER CONSTRUC-
TION)
EST LEG-EXT 13A
73-130-2H
TRIB.
DRAINAGE
AREA
ACRES/SQ. MI.)
32,842/
51.3
15.808/
24.7
4,0967
6.4
30,8487
48.2
20,4807
44.5
18,3687
28.7
1,2177
1.9
EXIST. POP.
SERVED IN
C.S. AREA
!
778,237
553,386
105,992
1,101,963
567,818
360,665
10,100
TUNNEL
DIAMETER
(FT.)
22 & 33
30
13 & 30
30
33
33
10
TUNNEL LENGTH
(FT./MI.)
51,770/9.8
22,607/4.3
20,374/3.9
25,189/4.8
26,000/4.9
18,804/3.6
18,260/3.5
NO. OF
DROP
SHAFTS
32
18
17
26
12
8
5
NO. OF
CONNECTING
STRUCTURES
79
26
63
43
22
12
7
STORAGE
CAPACITY
(TUNNELS ONLY)
(MG)
215.0
120.0 .
79.0
133.0
166.0
120.3
TOTAL STORAGE
CAPACITY (MG)
833.3
10.7
23
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TABLE 6
: MAINSTREAM TARP FLOW/LOAD EXPECTATIONS
i
Source: Facilities Planning Study MSDGC Update supplement & summary May 1984
1) Addison St. to Wilmette Harbor
72-049-2H & 73-058-2H
2) 59th to Central Avenue
73-160-2H & 13-163-2H
3) Central Ave. to Damen Ave.
75-126-2H & 73-163-2H
4) Damen Ave. to Roosevelt Rd.
75-125-2H & 75-120-2H
5) Roosevelt Rd. to Ogden Ave.
75-124-2H & 75-119-2H
6) Odgen Ave. to Addison St.
75-123-2H & 75-118-2H
estimated yearly* -
avg overflow Ib. of BOD
6,260,000 Ib
2,743,000 Ib
4,066,000 Ib
5,480,000 Ib
728,000 Ib
2,810,000 Ib
diverted and collected
by project due to
tunnel storage volume
overflow BOD
56%
85%
56.1%
54%
53.41
84.8%
65.7%
84%
80.3%
80.8%
84%
84%
*Based on calculated average 11.4 inches of rain result in overflows per year.
24
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TABLE 7: MAINSTREAM TARP - PRECIPITATION AND FLOW DATA
YEAR
1985
YEAR 1985
TOTALS
1986
YEAR 1986
TOTALS
MONTH
OCTOBER
NOVEMBER
DECEMBER
JANUARY
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
SEPTEMBER
OCTOBER
NOVEMBER
DECEMBER
NORMAL
PRECIPITATION
(IN. - EST.)
2.28
2.06
2.10
6.44
1.60
1.31
2.59
3.65
3.15
4.08
3.63
3.53
3.35
2.28
2.06
2.10
33.33
NO. OF
PRECIP.
EVENTS
11
20
11
42
7
13
8
11
10
11
12
6
14
10
11
7
120
PRECIPITATION
(IN.)
ACTUAL
4.32
8.22
1.49
14.03
0.39
2.60
2.49
1.84
3.11
3.49
4.30
1.11
7.12
3.75
1.41
1.09
32.70
TARP
FLOW (MG)
2582
4143
1793
8518
1020
2131
1745
619
2072
2972
2207
1798
3058
2751
1379
1194
22946
TOTAL FLOW
(MG)
23542
31733
22937
78212
19830
23424
25981
20948
26304
28268
29422
23964
25791
27039
23792
22105
296778
NOTES TO TABLE
1. TOTAL FIGURES (OCT. 1985 TO DECEMBER 1986)
NORMAL PRECIP. (EST.); 39.77 in.
NO. OF PRECIP. EVENTS: 162
PRECIPITATION (ACTUAL)': 46.73 1n
TARP FLOW (MGD): 31464 MGD
TOTAL FLOW (MGD): 374990 MGD
25
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TABLE 8: FINAL EFFLUENT DATA FOR WSWTW
MONTH/ YEAR
October 1985
November
December
January 1986
February
March
April
May
June
July
August
September
October
November
December
FINAL EFFLUENT DATA MG/L
BODq TSS AMMONIA NITROGEN
AVE.
5.0
5.0
6.0
11.0
11.0
12.0
11.0
8.0
4.0
7.0
7.0
8.0
8.0
11.0
12.0
MIN.
2.0
1.0
2.0
8.0
4.0
7.0
6.0
4.0
2.0
2.0
3.0
3.0
4.0
3.0
6.0
MAX.
9.0
11.0
12.0
15.0
18.0
23.0
14.0
13.0
11.0
13.0
14.0
14.0
13.0
20.0
20.0
AVE.
6.0
7.0
11.0
9.0
18.0
30.0
9.0
9.0
5.0
7.0
8.0
9.0
9.0
14.0
11.0
MIN.
4.0
4.0
7.0
7.0
6.0
6.0
6.0
3.0
2.0
3.0
2.0
3.0
3.0
5.0
6.0
MAX.
8.0
22.0
16.0
22.0
60.0
152.0
13.0
20.0
8.0
18.0
31.0
22.0
28.0
-48.0
20.0
AVE.
1.4
0.8
1.2
3.6
3.4
5.3
4.8
2.4
0.7
2.8
3.7
4.2
2.0
3.1
5.5
MIN
0.1
0.0
0.1
1.7
1.0
1.9
0.2
0.3
0.0
0.2
0.8
0.6
0.1
1.2
2.9
MAX.
3.6
2.7
3.7
7.9
5.9
9.9
12.7
4.9
2.5
7.9
7.8
8.0
3.9
5.9
8.0
Source: Data from Monthly Plant Operating Data
26
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CONSTRUCTION
Construction on the Mainstream system, exclusive of West Leg - ISA Exten-
tion, was performed under 11 different construction grants and 20 indi-
vidual contracts between June 30, 1975 and January 30, 1985. Included were
the 3 contracts for the Mainstream Pumping Station for which construction
first started in May 1979.
Construction was initiated by the construction contractors excavating a
large (greater than 25 feet) diameter construction shaft down to the speci-
fied tunnel elevation. The construction shaft excavations were accomplished
by a combination of two methods: drill-arvd-blast; and machine drill. The
bottoms of these shafts were typically oversized so that the tunnel boring
machine could be assembled. Additionally, small (3.5 feet) diameter access
shafts were installed during construction so that no point in the tunnel
was more than 3000 feet from surface access.
The drop shafts, used to convey combined sewer overflow from the high level
sewers to the tunnel , are constructed in a similar manner. Drop shafts
range in size from 4.5 to 17 feet in diameter, and are of two main types:
those with the vertical shaft divided into two sections (one to allow air
entrained in the water to be vented); and, those 12 ft. diameter and larger
with a separate air vent shaft. All shafts are concrete lined either with
precast concrete (9 ft. or smaller) or cast in place concrete. Segments
of the main tunnel are lined with a minimum 12-inch thickness of concrete.
Concrete for tunnel lining was produced by stationary batching plants
located above ground at access shafts. The exception was the use by one
contractor of a moveable batching plant situated in the tunnel itself which
moved along the tunnel as construction progressed. This method provided no
apparent cost benefit to the project. The lining of the tunnels with
concrete contact grouting was performed to fill any voids left during the
lining operation and to minimize groundwater inflow. Presence of dripping
water, wet concrete surfaces and vertical construction joints was used in
locating contact grout holes. The amount of grout used varied considerably
in each segment of the tunnel depending on the type of rock, number and
size of fault lines and bedding planes, number of joints, and amount of
structural disturbance. Grouting is heavier where drill and blast occurred
in the tunnel and shafts. Grouting is generally effective in reducing
groundwater inflow to within specified limits. The joints where shafts
connected with the tunnel are especially susceptible to inflow even after
grouting. Inflow in the major tunnel portion between Addison Street and
59th Street (tunnel length 21.4 miles) is 1046 gallons per minute (gpm)
(1.5 MGD) after grouting was completed, compared with an estimated 2267 gpm
before grouting. Target inflow is 50,000 gallons per day per mile of
tunnel (1.07 MGD for this tunnel portion). Though substantially reduced,
groundwater inflow into the tunnel and shafts exceeded the target rate by
50 percent. Groundwater inflow to the tunnel, even at 1.5 MGD, represents a
small increment in terms of the total volume of water processed through TARP.
27
-------
BLASTING
Excavation of the drop shafts, contractor shafts and tunnel boring machine
setup chamber was done by blasting and/or downbore methods. Drill-and-
blast excavation consisted of drilling a pattern of holes, loading the
holes with explosives, and detonating the explosives. The construction
shafts were located at undeveloped surface areas so that blasting of the
shafts and chambers would not result in undesirable effects from blast in-
duced vibrations.
The contract documents required the contractor to hire a qualified seis-
mologist to monitor and record all blast induced vibrations. Recom-
mendations for blasting methods and size of charges, as well as monitoring
of the vibrations, were made by VME-NITRO Consult, Inc. Residents and
businesses in the vicinity of blasting were notified in advance. A de-
tailed preblast survey was then usually conducted. The survey consisted of
documenting the existing conditions of structures located in the proximity
of the proposed blasting with photographs and descriptions.
Three out of five contractors (5 contracts on Mainstream) conducted the
preblast survey. This was done on Contracts 73-160-2H ($38,000), 75-125-2H
($7,700), and 75-123-2H ($30,800) for a total cost of $76,500. Particular
restrictions were enforced on Contract 73-160-2H, which passed thru the
Villages of Summit and Forest View. The Village of Forest View passed a
more restrictive blasting ordinance after the contract was awarded, result-
ing in delays to the blasting operations. The Contractor was required to
pre-survey every residential and business structure in the Village and
guarantee to repair all damage resulting form this work. A $300,000 bond,
requested by the Village due to the close proximity of the Village's water-
line to the blasting area, was waived when MSDGC and the Contractor agreed
to immediately repair any damages that may be caused to the waterline.
In the Village of Summit, the contractor was required to only allow blast-
ing activities from 8:00 A.M. to 8:00 P.M. Additionally, copies of all
blasting complaints had to be submitted to the Village Clerk.
At the present time, due to numerous complaints from homeowners regarding
alleged damage resulting from blasting, the MSDGC board has set up a
temporary committee (Property Owner's Protective Committee) to study ways
that this issue may be resolved to the satisfaction of everyone concerned.
In addition, alternative methods of excavating the drop shafts are currently
being investigated.
MAINSTREAM OPERATION
Mainstream TARP collects and stores for subsequent treatment the combined
sewer overflows from a large part of the Chicago area. The tunnel system
presently consists of 31.2 miles of tunnel with an associated storage
capacity of 3020 acre feet. Any flow exceeding the capacity of the tunnel
system is discharged untreated to the local waterways. To effectively
operate this system, 128 collecting, 66 regulating, and 3 control structures
are used to divert flows to 115 TARP drop shafts. The system also includes
110 interceptor connections to the tunnel system.
28
-------
Data on the Mainstream TARP is included in the MSDGC "Monthly Plant Oper-
ating Data" as part of the WSWTW Chapter. This data which includes WSWTW
process streams (influent, effluent, pumpage, etc.)> only includes the
daily volume of pumpage from Mainstream TARP. Qualitative data is not
regularly collected but several short duration special studies collected a
minimal amount of information.
Because the present storage capacity of the system is exclusively that of
the tunnel, the processing flow rate at the WSWTW establishes allowable
tunnel inflow rates and dewatering schedules. The tunnel inflow is
regulated by sluice gates which are controlled and monitored at the WSWTW
process control building through the supervisory control and monitoring
system.
The operation of the tunnel system occurs in two phases:
(1) tunnel filling and flushing; and,
(2) pumping.
Tunnel filling during a storm event is initiated either after an overflow
condition exists and the WSWTW process control building operator opens
the sluice gates to divert flow into the tunnel (Figure 4) or when CSO is
diverted through uncontrolled tunnel diversion structures. All con-
trolled sluice gates are normally kept closed to avoid unnecessary diver-
sion of dry weather flow to TARP. During the initiation of a rainfall
event, the flow in the sewers increases until at a prescribed level, flow
is channeled through the collecting structure to the CSO outfall sewer.
Sufficient flow through the outfall sewer opens the tide gate which acti-
vates an alarm warning light on the TARP control panel located at the
WSWTW, alerting the operator that the outfall is discharging to the river.
If there is sufficient storage capacity within the tunnel, the operator
will open an appropriate number of sluice gates (one or more depending on
location) to divert sewage from the overflow to the tunnel via the drop
shaft. This is usually sufficient to stop the overflow. If after 20
minutes the tide gate alarm light remains lit, additional sluice gates are
opened. This 20-minute cycle continues until the tide gate closes.
This prescribed operating procedure virtually assures that some amount of
the combined sewers' "first flush" of pollutants enters the receiving
waters prior to diversion to the tunnel. The amount of this discharge will
vary depending upon the activities of the operator at the time of initia-
tion of an overflow, as well as the time of response in order to open
multiple sluice gates in sequence as an overflow event proceeds. Though
potentially low in volume, the initial "first flush" of the combined sewer
system typically has elevated suspended solids and organic levels. MSDGC
has estimated that this represents less than 1.0 percent of the combined
sewage pollution load.
Diversion of sanitary sewage to the tunnel can also be accomplished when in-
dividual interceptor sewer or WSWTW plant capacity is exceeded. This can be
done by opening the tunnel drop shaft sluice gates in one of thirteen areas
29
-------
Motostrtom
Tunnel
FIGURE 4
Tide Gote Structure
Collecting Structure
Eiisting Sewtr-^ )'
Connecting Sewer-
Drop Shoft
O
s ,
J '
^Flow
Rtguloting Structure,
(Sluice Gotes)
PLAN
Regulotmg Structure
(Sluice Gotesl
Drop Shoft
Geode
yjr
Tide Gote
Structure
Connectin
Sewer
JC
Connecting Structure
: Momstreom
Tunnel
Source: Operation and
Maintenance Manual
(Mainstream TARP)
SECTION
PROJECT:
. TUNNEL AND RESERVOIR PLAN
THE METROPOLITAN SANITARY DISTRICT
OF GREATER CHICAGO-
TYPICAL COMBINED SEWER OUTFALL
CONNECTION TO MAINSTREAM TUNNEL
-------
(Figure 5). This is a function of TARP which has never been used but can
"protect the system from sporadic treatment plant overloads and/or isolated
dry weather bypassing.
The diversion of wet weather flow continues until certain tunnel levels are
reached. For rains forcasted to be less than one inch, the pump stations
at Racine and Lawrence Avenues are activated at 40% tunnel capacity, pump
ing their overflows into the waterways. At 50% capacity, all controlled
sluice gates are closed, starting with the northern most gates. Inflow to
TARP continues from the uncontrolled gates, which account for 10% of the
total flow to the tunnel system. Overall, there are 52 ungated locations
on the Mainstream system. Of these, the MSDGC is putting in slide gates
on the 15 largest flow contributors, each presently allowing 150 cfs or
greater. Table 9 contains information on the ungated Mainstream drop
shafts. For rains forecasted to be greater than 1-inch, all controlled
inlets into TARP remain closed. The only flow into TARP is from the uncon-
trolled dropshafts. This operation strategy is a result of past operating
experiences where geysering problems were caused by TARP filling up too
quickly. The geysering was the result of water being entrained in the air
vented from the tunnel during filling. The Mainstream Operation and
Maintenance Manual, developed by Harza Engineering Company, recommended
closing the sluice gates when the tunnel is full. MSDGC is having St.
Anthony Falls Laboratory model the hydraulics of the Mainstream TARP in
order to get a better idea of how the system operates. This knowledge will
be utilized to modify the operating procedures to operate TARP more effici-
ently. The modeling is expected to be completed in early 1988.
Mainstream TARP is dewatered by the Mainstream Pumping Station, located
near the junction of the Mainstream and the proposed Lower Des Plaines tun-
nel systems. The pumping station has a total capacity of 1100 cfs at 330
feet of head and 490 cfs at 150 feet of head. The captured combined sewage
is pumped to WSWTW for treatment. According to the Mainstream Operation
and Maintenance Manual, a 60-hour dewatering criterion has been established
for the tunnels. Primary considerations in the dewatering of TARP are the
available capacity at WSWTW to treat the extra flow and the necessity of
having storage capacity available for upcoming rainfall events. Peak ca-
pacity at WSWTW, with all four aeration batteries working, is 1440 MGD.
The MSDGC targets peak flow normally used at 1200 MGD. However, constru -
ction at WSWTW has temporarily reduced the available treatment capacity to
1080 MGD peak flow, with a normally used target of 900 MGD peak.
Another major consideration is the high electricity cost to run the Main-
stream pumps. Unless conditions dictate otherwise, the pumping, which is
ideally controlled at the WSW process control building but can also be
controlled at the pumping station, is scheduled to take advantage of off-
peak electric rates which are less than one-half of the peak energy rate
(2.756 vs 5.811£ per kilowatt hour). This energy savings represents
31
-------
\. Moinstreom
Tunnel
Existing Interceptor
Or Sewer
Connecting
Structure
Drop Short
Regulating Structure
(Sluice Gotes)
Connecting
Sewer
Connecting
Structure
: Drop Shoft
Regulating Structure
(Sluice Gotes)
. Mainstream
Tunnel
Source: Operation and
Maintenance Manual
(Mainstream TARP)
SECTION
PROJECT:
TUNNEL AND RESERVOIR PLAN
THE METROPOLITAN SANITARY DISTRICT
OF GREATER CHICAGO-
TYPICAL INTERCEPTOR CONNECTION TO
MAINSTREAM TUNNEL
32
-------
TABLE 9: MAINSTREAM TARP - Ungated Locations
Cumulative
Category Total Flow (cfs) % of Total Flow Locations Location
1 - >200 cfs 2827 49 10 10
2 - 150 - 200 844 15 5 15
3 - 100 - 150 685 12 5 20
4 - 50 - 100 990 17 14 34
5 - <50 410 7 17 51
Cat. 1 includes 300 cfs @ Howard Street connection still under construction
33
-------
several hundred thousand dollars per year in operating costs. The off-
peak times are 10:00 p.m. to 9:00 a.m. on weekdays, anytime on weekends,
holidays, and the Mondays or Fridays associated with Tuesday/Thursday
holidays. Normal dewatering during dry weather is performed during these
off-peak times. During wet weather, the same schedule is followed except
the starting time on weekdays is moved up to 5:00 p.m. An item that is
taken into account in the dewatering process is the hydrogen sulfide gen-
erated by the stored combined sewage. Hydrogen sulfide poses problems from
the standpoint of being a poisonous gas as well as the potential for cor-
rosion in the sewer and at the treatment plant. Hydrogen sulfide is formed
when the sewage is retained between pumpings in the tunnels from the Main-
stream Pumping Station to the WSWTW. When this combined sewage is pumped,
hydrogen sulfide is detected at WSWTW. If the hydrogen sulfide levels are
a problem during pumping, the dewatering is cut off at 7:00 a.m., before
many of the WSWTW dayshift begin work. MSD6C has attempted to remedy the
hydrogen sulfide problem by injecting oxygen into the pumped sewage. This
has been found to help after the pumping has started. However, the con-
centration of hydrogen sulfide is still high at the onset of pumping.
MSDGC is looking into other alternatives to control the hydrogen sulfide.
One of these methods being considered is the addition of hydrogen peroxide
to the stored sewage.
MAINSTREAM PERFORMANCE
The performance of Mainstream TARP has been a result of the procedures
described earlier. The system has not been operating as originally an-
ticipated for three reasons. First, an unknown amount of combined sewer
overflow is discharged to the receiving water prior to diversion to TARP.
Second, actual operating experience has required the modification of the
way the tunnel system is operated during large storm events due to the
geysering problem. Third, construction at the WSWTW has temporarily
reduced the capacity available to dewater TARP.
Over the 15 months on which this report is based, 31,464 MG of stored
combined sewage has been pumped to WSWTW. Over this time period, 46.73
inches of rain has fallen in the Mainstream drainage area. There has been
an increase in the solids handled at WSWTW from approximately 400 tons per
day for 1982-84 to approximately 436 tons per day in 1985, with TARP in
operation only part of the year, to approximately 500 tons per day in 1986
with TARP in operation the full year. This increase in solids is partially
due to the operation of Mainstream TARP and to the increased recycle from
the treatment plant imhoff tank and sludge digester.
Pumpback from TARP is limited by the operator to available hydraulic capac-
ity at the plant. This ensures that total flow to the plant is within the
design limits or available capacity based upon currently ongoing construc-
tion projects. As such, there appears to be no degradation of effluent as
a result of TARP pumpbacks. On the contrary, pumping during the off-peak
34
-------
electrical rate hours (nights and weekends) helps to equalize diurnal flow
variations to the plant which potentially results in more consistent
operation.
The main detriment to TARP pumpback at non peak energy rate times is that
the tunnels are not dewatered within the 60-hour dewatering criterion
originally established' for the system. Figure 6 illustrates the volume of
storage capacity available in Mainstream TARP for 1986. For reference, a
plot of the rainfall events is also included in the figure. As can be seen,
the TARP tunnels are filled for extensive periods of time. However, full
tunnel storage capacity is generally available except for extreme wet
weather conditions such as those that occurred in October 1986. As such,
it appears that the operating cost savings of the slower tunnel dewatering
rate would have only a minimal effect on potential CSO discharges over an
extended period of time.
35
-------
a: •
o _ !j
s:
MAINSTREAM TUNNEL VOLUME STORED
FIGURE 6
1966
JAN FIB MAP APR MAY JUN JUL AUG SEP OCT NOY DEC
RAINFALL
4* *M» MAT
-------
CHAPTER 5
CALUMET TARP SYSTEM
DESCRIPTION
The present TARP Phase I system for the Calumet area consists of 9.2
miles of deep tunnels (27.7 miles yet to be completed for a total of 36.9
miles of deep tunnels), the Calumet TARP pumping station, and the Calumet
treatment plant (see Fig. 7 and Table 10). A second pumping station (yet
to be constructed) will be located near the O'Brien Locks. This station
will provide supplemental conveyance capacity to prevent combined sewer
overflows from entering the waterway on the Lake Michigan side of the
O'Brien Locks. The present storage capacity of the Phase I Calumet TARP
tunnel system is 180 MG. When the tunnel system is completed, it will
have the capacity to store more than 540 MG of untreated wastewater. The
tunnels are sized to permit limited spillage to the Little Calumet River
and the Calumet - Sag Channel. None of the overflow will be allowed to
spill into that portion of the Little Calumet River upstream of its
junction with the Calumet - Sag Channel. Two-thirds of the Calumet TARP
tunnel system has controls (i.e., for 2/3 of the system, flows to the
tunnels can be controlled by means of automated sluice gates at the drop
shafts to the TARP tunnels).
There are 5 connections from intercepting sewers to the Calumet TARP
tunnels that discharge wet weather flow into TARP, with no built-in cap-
ability to limit these flows. These connections continue to discharge
into the Calumet TARP tunnels 3-4 days after rain events due to rainwater
storage capacity in the local intercepting sewer. In addition, the
Calumet TARP tunnels are also currently accepting dry weather flows from
a recently completed (November 1986) tunnel extension. This dry weather
flow is estimated to be about 3-5 MGD. It is anticipated that when the
Calumet TARP tunnel system is fully operational, some dry weather flow will
be continuously entering the system due to the overloaded capacity of the
area's intercepting sewers.
CONSTRUCTION
The construction of the Calumet TARP pumping station, as well as, the
Calumet TARP tunnels has generally proceeded on-schedule. The Calumet
TARP pumping station went on-line in October 1985. The station was
scheduled to become operational in early 1985, but vibrational problems
with the pumps had to be resolved before commencing operations.
37
-------
FIGURE 7
-1
CALUMET
TREATMENT
PLANT
PHASE I TUNNEL
PHASE 2 TUNNEL
PHASE t TUNNEL COMPLETED
i I PREVIOUSLY COMPLETED TUNNEL
• PHASE I PUMPING STATION
• PHASE 2 PUMPING STATION
Source:
CHICAGOLANO UNDERFLOW PLAN
PHASE I COM
CALUMET SYSTEM
OF TARP
CORPS OF ENGINEERS CHICAGO DISTRICT
38
-------
TABLE 10
CALUMET TUNNEL SYSTEM (CRAUFORD AVENUE TO PUMPING STATION)
CONTRACTS 73-287-2H and 73-273-2H
I. General Data
Design Area 27,450 acres/42.9 sq. mi.
Existing Population Served in 417,300
Combined Sewered Area
Yearly Average Rainfall 33.2 inches
Yearly Average Overflow 11.4 inches
Yearly Average BOD in Overflow 4,880,000 pounds
Runoff Captured by Project 59%
BOD Captured by Project 78%
Tunnel Storage Capacity 113,400,000 gal. = 562,000 cu. yds. -
348 acre - feet =0.5 in. of runoff
II. Contract 73-287-2H (Tunnels and Shafts)
Estimated Construction Time = 1,684 days/4.6 years
Tunnel Sizes
21' - 0" Dia. (unlined) 42,029 feet/7.96 miles
21' - 0" Dia. (lined) 370 feet/0.07 miles
12' - 0" Dia. (unlined) 317 feet/0.06 miles
9' - 0" Dia. (unlined) 5,491 feet/1.04 miles
48,207 feet/9.13 miles
Drop Shafts - 17
Access Shafts - 4
Construction Shafts - 1
Total ~22~
III. Contract 73-273-2H (Connecting Structures)
Estimated Construction Time = 1,340 days/3.7 years
Type of Connection
Drop Shaft Connection 16
Drop Shaft Connection and 6
Existing Interceptor Relief
Overflow Connection to
Existing Interceptor
Total
Source: Facilities Planning Study - MSDGC
Update Supplement and Summary, May 1984
39
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OPERATION
The operating goal is to dewater the Calumet TARP system daily during the
12-8 a.m. time slot in order to equalize the flows to the Calumet treat-
ment plant; At the present time, dewatering is limited by insufficient
treatment plant capacity. The capacity of the Calumet plant during the
study period was at an average dry weather flow of 236 MGD, an extended dry
weather flow of 250 MGD, and a maximum flow (handled on a limited basis) of
280 MGD. The current set point for dewatering TARP is 245 MGD. That is,
if all incoming flows to the Calumet plant are less than 245 MGD, the
Calumet TARP tunnels will be dewatered until a flow, to the plant, of 245
MGD is achieved. The completion of the Calumet wastewater treatment plant
expansion has been delayed by the unforeseen circumstance of the bankruptcy
of the blower construction contractor. The tentative schedule for bringing
the capacity of the Calumet plant up to 1.5 times the average dry weather
flow in order to be able to treat all incoming flows, calls for aeration
capacity to be installed by the fall of 1987. Once the aeration capacity
is installed, it will take about 6 months before efficient operation of
the total system can be expected. The ultimate design flow of the Calumet
treatment plant is 354 MGD. This is the required capacity of the Calumet
treatment plant to accommodate a TARP dewatering rate of 118 MGD.
The operating procedures for the Calumet TARP tunnels in terms of control-
ling flows into TARP, as well as dewatering, are contained in the document:
"Operational Plan - Supplemental to Operation Manuals - Tunnel and Reservoir
Plan, Calumet System (March 1983)." Due to the inadequate treatment capac-
ity of the Calumet treatment plant at this time, however, the Calumet TARP
system is not being operated according to the procedures set forth in this
manual. As mentioned previously, if incoming flows to the Calumet.treat-
ment plant are less than 245 MGD, dewatering of the TARP tunnels will
commence until a 245 MGD rate is achieved. As there is continuous inflow
of dry weather flows to the TARP tunnels, this situation has resulted in
flows being bypassed. From October 1985 (when the Calumet TARP tunnels
became operational) to November 1986, about 86% of the total flow pumped
from the Calumet TARP tunnels has been bypassed to the Little Calumet River.
Data on the Calumet treatment plant process streams (influent, effluent,
pumpage, etc.) is collected daily and compiled in a monthly operating re-
port (see Table 11). Beginning in September 1986, data from the operation of
the Calumet TARP system has also been included in the reports. This data
consists of electrical energy consumption by the Calumet TARP pumping station
and pumpage rates from the TARP tunnels to either the treatment plant or the
Little Calumet River. The MSDGC has also compiled separate records of
pumpage rates from the Calumet TARP tunnels beginning in October 1985. This
data includes number of hours pumps (in TARP pump station) were operated,
as well as the rate of flow to either the plant or the river on a monthly
basis (see Table 12). Qualitative data (BOD and SS) on flows pumped from the
Calumet TARP tunnels is collected Monday thru Friday by grab sampling (see
Table 13).
40
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TABLE 11
CALUMET EFFLUENT DATA
MONTH/YEAR
October 1985
November
December
January 1986
February
March
April
May
June
July
August
September
October
November
December
BODs (mg/1
AVE.
19
18
27
32
18
17
23
21
20
15
15
20
19
27
24
MIN.
9
11
12
19
12
11
12
12
11
7
9
14
11
10
12
MAX.
33
30
37
76
24
24
34
33
39
28
25
35
28
45
31
TSS (mg/1 )
AVE.
21
13
20
26
23
21
23
23
17
10
11
16
11
21
14
MIN.
11
6 .
11
17
13
9
16
12
5
5
5
9
6
15
4
MAX.
65
24
27
37
35
40
39
38
48
32
21
32
17
42
22
NH^ - N (mg/1 )
AVE.
11.7
5.6
7.5
12.9
12.9
12.5
14.3
15.8
11.1
6.5
8.2
9.2
5.7
6.5
5.4
MIN
5.2
1.1
1.6
8.6
9.0
9.1
9.2
7.2
5.8
3.2
3.0
3.0
1.2
2.1
2.5
MAX.
16.3
12.9
11.5
17.0
18.2
21.2
20.4
20.6
18.0
11.6
54.0
13.0
11.3
10.0
10.0
41
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TABLE 12
C_ALUMEJ_TARP PUMPING
1985
MONTH
OCT
NOV
DEC
PUMP
HOURS
129.6
163.7
7.6
MILLION GALLONS FLOW TO
PLANT
68.5
267.2
12.8
RIVER
257.9
0
0
TOTAL
326.4
267.2
12.8
1986
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEPT
OCT
NOV
36.7
81.1
287.6
128.5
262.0
370.4
353.6
97.7
337.1
338.9
273.1
75.9
105.3
0
0
0
0
0
0
103.6
118.1
152.4
0
108.3
738.1
202.7
458.7
669.4
969.8
247.6
774.3
748.0
468.2
75.9
213.6
738.1
202.7
458.7
669.4
969.8
247.6
877.9
866.1
620.6
42
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TABLE 13 CALUMET TARP DISCHARGE QUALITY
Belcw is listed laboratory data generated in 1986 on the Ta:
ss.-.ples collected.
12/13/86
12/11/S6
12/4/36
12-/1/S6
11/23/65
11/25/86
11/24/86
11/19/86
11/14/86
11/5/86
11/2/86
1C/16/86
1C/15/86
10/14/86
10/13/86
10/7/86
10/6/86
10/1/86
9/26/86
9/13/86
9/17/86
8/19/86
6/4/86
8/1/86
7/31/86
7/25/86
7/21/86
7/20/66
7/19/86
7/18/86
7/17/86
7/16/86
7/11/86
7/7/86
6/3C/86
6/2S/86
6/5/86
5/31/86
5/30/86
5/29/66
5/28/86
5/27/86
5/20/86
5/14/S6
5/1/86
4/25/86
4/2/86
4/1/86
3/31/86
3/23/86
3/26/66
3/20/36
3/14/86
3/13/36
3/12/35
2/11.'£6
3/7/65
3/6/S5
3/5/35
3/4/86
2/3/86
NA
7.5
7.1
NA
NA
7.3
7.3
7.2
7.2
NA
NA
NA
7.3
7.0
7.6
7.2
7.4
7.6
7.2
NA
NA
7.3
NA
NA
NA
NA
7.5
7.4
NA
NA
NA
7.2
7.5
7.2
7.1
7.1
7.2
7.3
7.4
7.5
7.2
7. 3
~'.6
NA
NA
7.3
7.6
6.7
7.4
7.3
€ . 6
7.5
*:.-.
7.S
7.6
7.2
7.5
8.0
s.o
ss
57
46
33
ISO
80
240
32
170
45
118
400
72
76
84
116 •
2130
154
74
26
32
290
74
46
184
39
144
118
610
160
118
496
152
61
166
92
396
86
51
126
73
132
150
102
74
215
40
258
98
43
36
54
47
21
46
35
31
69
66
33
67
25
V=S
33
30
24
120
50
150
20
120
28
78
330
68
38
54
62
1630
66
50
18
16
194
44
40
102
28
74
76
290
66
60
216
78
37
106
64
210
44
34
62
42
102
63
62
52
151
31
142
71
28
12
36
31
19
23
21
21
73
40
26
49
IS
BCD
50
75
60
40
110
200
51
67
SI
123
275
NA
38
178
NA
NA
NA
69
98
135
NA
66
85
170
75
110
71
86
123
83
115
107
44
77
130
173
43
NA
105
97
43
60
115
76
101
NA
NA
156
94
73
84
€3
13
61
47
70
20
94
86
104
42
43
-------
The projected operations and maintenance (O&M) costs for the Calumet TARP
system (see Table 14) will increase as more of the system comes on-line
and becomes fully operational. As can be seen, the biggest expense is
for electricity which accounts for about 64% of O&M costs in 1986 and 74%
of O&M costs in 1987.
PERFORMANCE ;
At this time, no judgement can be made as to the effect Calumet TARP de-
watering will have on the performance of the Calumet treatment plant. The
plant is currently being upgraded to include additional aeration capacity
in order to accommodate the additional flows resulting from TARP dewater-
ing activities. Also, the treatment plant will be expanded to an ultimate
design capacity of 354 MGD, so that all dry weather flows, as well as
anticipated flows resulting from TARP dewatering, can be treated to the
levels indicated in Calumet's NPDES permit.
44
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TABLE 14
OPERATION AND MAINTENANCE COSTS
CALUMET TARP SYSTEM
(Projected)
Category
Operating Labor
Maintenance Labor
Parts and Material
Utilities
Electricity
Water
Overhead
TOTAL
0 & M Costs ($)
1986
167,500
119,200
74,300
744,000
30,000
35,000
1987
190,000
131,000
62,000
1,240,000
35,000
20,000
1,170,000
1,678,000
Source: Data supplied by MSDGC
45
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CHAPTER 6
GROUNDUATER MONITORING
INTRODUCTION
This chapter evaluates the groundwater monitoring programs implemented by
MSDGC for each of the three TARP Phase I segments examined in this project.
The Environmental Impact Statement (EIS) for each segment recommended a
groundwater monitoring program to evaluate the impacts of infiltration and
exfiltration that might occur during the operation of the tunnels. This
chapter describes the monitoring programs recommended by the EIS's, the
proposed MSDGC programs, and the programs as implemented by MSDGC. Based
on a review of the data collected and reported by MSDGC, this chapter
assesses the adequacy of the existing programs and also makes recommenda-
tions for improving the effectiveness of these programs in monitoring
impacts to groundwater from the TARP Phase I projects.
The TARP tunnels are located within the Silurian Dolomite system. This
system is considered tight and very impervious. Concrete lining and grout-
ing to seal joints and bedding planes were proposed to provide a barrier
to the surrounding groundwater. nfiltration of water into the tunnels due
to hydraulic pressure outside the tunnels was identified during planning
as one potential problem. Infiltration can lead to lowering of the local
water table and decreased tunnel capacity. Without grouting, the infiltra-
tion was estimated to be as high as 1.4 MGD/mile (average 0.5 MGD/mile.)
This could represent up to 15% of the tunnel capacity. The design limit
for the grouting program was 0.05 MGD/mile. Infiltration occurs during dry
periods (when the tunnel is empty) or small storm events, when the pressure
in the tunnels is below the piezometric level. The grouting was designed
to mitigate this impact of infiltration to the tunnels.
Another concern during planning was the potential for exfiltration of waste-
water from the tunnels into the surrounding aquifer. Exfiltration could
prove to be a long term negative impact on the quality of the groundwater.
The natural high groundwater exerts an inward pressure on the tunnels most
of the time. Following major storm events or when the tunnels are full,
the pressure in the tunnel is greater than that outside, thus exfiltration
occurs. It was expected that exfiltration would occur during these
"surcharge" events, but that a rebound effect would occur in which the
infiltration of water into the tunnel would account for any contaminants
that were exfiltrated into the acquifer. Again, grouting is essential in
minimizing the amount of exfiltration that occurs. A worst case analysis
was conducted during facilities planning to assess the potential for exfil-
tration to impact water mains. Since the tunnels will be located nearly 70
feet below any main, it was determined to be unlikely that exfiltration
would have any impacts. Quality sampling wells were located in areas of
high grout uptake and in areas with unfavorable geologic conditions, where
exfiltration potential is greatest.
MAINSTREAM
0 Proposed/Approved Monitoring Program
The May 1976, EIS (p.X-7) recommended a routine groundwater monitoring pro-
gram to determine whether exfiltration or infiltration was occuring in the
46
-------
tunnels. It was recommended that the monitoring wells be equipped with
continuous level recorders to be used for correlating aquifer pressure
with tunnel pressure. The EIS also recommended a quality sampling program
for the monitoring wells. The sampling of the wells was recommended to
occur weekly and after major storm events. As a minimum program, it was
recommended that the following parameters be measured on a weekly basis:
0 NH3 (as nitrogen)
0 Total Bacteria Plate Count
0 Conductivity (or calculated TDS)
0 Total Organic Carbon
The EIS stated that a monitoring program would be included as a grant condi-
tion for the Mainstream tunnel system and that specific design criteria for
the monitoring would be included in construction permits. The final EIS
called for USEPA, IEPA and MSDGC agreement on the location, depth and time
parameters for the monitoring program.
The Step 3 grant agreement of July 1, 1976, for the Mainstream project included
a condition for a groundwater monitoring program. The grant condition was as
fo11ows :
"The grantee agrees to submit a plan, prior to any actual construction
which may affect groundwater conditions, for implementation of a ground-
water monitoring system with sampling parameters and frequencies mutually
agreeable to the Illinois Environmental Protection Agency and the U.S.
Environmental Protection Agency, sufficient to detect any changes in
groundwater quality resulting from construction and operation of the Main-
stream Tunnel System, of which the project scope defined below is a part,
and further agrees to plan and develop an emergency groundwater recharge
program and to implement same in the event of significant exfiltration of
combined sewer waters from the tunnel system into the groundwater aquifer."
A monitoring program was developed by MSDGC in 1979. A technical report en-
titled Groundwater Monitoring Program Mainstream Tunnel System - Addison St.
to 59th Street was prepared in January 1979, and revised in January 1980,
June 1980, and July 1983. This report indicated that the monitoring program
would be included in the Mainstream O&M manual. The program would include:
maintenance of 25 groundwater level observation wells along the tunnel align-
ment and at the Mainstream Pumping Station; monitoring of hydraulic grade
line measurements and pumpage records; and installation and operation of 17
groundwater quality monitoring wells. MSDGC would provide semi-annual re-
ports to IEPA.
Fifty-three observation wells were used during the pre-construction phase for
subsurface exploration. Due to construction activities, vandalism or new
paving, only two of the original wells were found to be usable for the ground-
water monitoring program.
The two original wells and twenty-three new wells were planned for use as level
observation wells. The plan called for bi-weekly monitoring of piezometers.
47
-------
These level observation wells were to be installed such that they would
allow entrance of groundwater from 25 feet below the top of the bedrock
to 3 feet below the tunnel invert. Seventeen groundwater quality wells
were planned for monitoring both the quality and level of the groundwater.
The quality wells would be uncased approximately 20 feet below the tunnel
invert to approximately 20 feet above the crown. The groundwater level
would be monitored by continuous level recorders. Quality analysis would
be monitored according to USEPA procedures outlined in the Handbook for
Analytical Quality Control in Water and Wastewater Laboratories, EPA /600/
4-79-019. Quality monitoring was planned to occur on a bi-weekly basis
or until less frequent monitoring is justified and approved by IEPA.
Monitoring would also occur after storm events. The monitoring program
would address the following parameters: pH, Chlorides, 8005, Hardness,
Alkalinity, NH3-N (as nitrogen), Total Phosphorus, COD, Conductivity,
Total Suspended Solids, and Fecal Coliform.
Appendices C and D of the July 1983 Technical Report identified the loca-
tions of the wells. Fifteen quality and nineteen level wells would be
located along the tunnel alignment, and two quality and six level wells
would be located at the Mainstream Pumping Station. Monitoring wells
would be located in areas of heavy grouting, in close .proximity to potable
water tunnels, and uniformly spaced (every 3/4 mile) along the alignment.
The wells would be offset thirty feet from the edge of the tunnel.
The Mainstream TARP Groundwater Monitoring Program (January 1980 with June
1980 revisions) was found to be acceptable by USEPA and IEPA on December 3,
1980. It was noted that the sampling frequency was changed from weekly to
biweekly in the July 1983 revision, but was not approved by USEPA.
0 Analysis of MSDGC Data
The analysis of the groundwater monitoring data is based upon the following
documents:
0 Groundwater Monitoring Program - Mainstream January 1980 (Revised
July 1983)
0 Groundwater Monitoring Program - Appendices C and D Mainstream July
1983
0 Groundwater Monitoring Program - Mainstream - December 1986.
In all, 17 groundwater quality monitoring wells and 25 observation wells are
used to assess the Mainstream system (See Figure 8). The quality monitoring
wells are equipped with continuous level recorders which record the level
in the wells every 12 hours. This data is retrieved from the recorder every
three months and stored in a computer. The water quality and level data are
available for the period from November 1985 through October 1986. This short
period of time is not sufficient to establish any seasonal or yearly trends.
The sampling frequency is for the most part bi-weekly, except for instances
where conditions make it impossible to collect samples.
48
-------
Monitoring well
Piezometer
UNOEK CONSTRUCTION
jmeters and
boring wells
i at Pumping
MODOONS
KMPMC
STATMN
•• PHASE 1 TUNNEL
PHASE 2 TUNNEL
PHASE 1 TUNNEL COMPLETED
PREVIOUSLY COMPLETED TUNNEL
PHASE 1 PUMPING STATION
ON-LINE RESERVOIR
4
A
CNICUOLUB MCl'lOt
nun i IN
MAINSTREAM SYSTEM
OP TARP
MONITORING WELLS
Of
49
-------
- Water Level Measurements
The general trend for the 17 quality monitoring wells located along the
tunnel indicates the water levels are decreasing with time during the
November 1985 to October 1986 period for most of the wells. Data taken
in the late 1970's, as summarized in the previous reports, stated there
was no trend. However only summary data was reported so this statement
jcould not be confirmed.
We recommend the future monitoring program continue monitoring wells as
decribed in the Overview Section of this chapter, to determine if there
is a correlation between tunnel water levels and piezometric head in the
monitoring wells.
- Water Quality Results
The Mainstream tunnel system can be divided into two sections:
1. Archer Avenue and Halsted Street and north
2. Archer Avenue and Halsted Street to the Mainstream Pump Station.
The first system section experienced little groundwater contamination.
The fecal coliform levels did not exceed 2/100 ml and interestingly the
hardness and alkalinity did not vary as much as the downstream tunnel
system. The second section also experienced higher fecal coliform
counts as much as 6000/100 ml, with six wells reporting at least 580/100
ml during the sampling period. .The large variations in hardness and
alkalinity could indicate the intrusion of contaminated tunnel water and
infiltrating surface water.
0 Recommendations
Clearly, the monitoring wells by the lower section of the Mainstream
tunnel indicate groundwater contamination is occuring, but the cause and
the potential long term extent of this contamination are not clear. Addi-
tional water level measurements should be performed as decribed in the
overview portion of this chapter to determine if the tunnel is intercon-
nected with the dolomite strata during potential exfiltration events. In
addition, the hydrogeologic relationship of the Chicago River, the Des
Plaines River and the Sanitary and Ship Canal to the aquifer system should
be documented.
If a relationship between the tunnel and the aquifer system is defined,
a water quality plan can be designed to accommodate the lag time in the
well's exfiltration response.
UPPER-DES-PLAINES (O'HARE)
0 Proposed/Approved Monitoring Program
The May 1975, EIS for the O'Hare Service Area - Wastewater Conveyance System
(Upper Des Plaines tunnel project) stated that the operation of the tunnels
50
-------
should have little impact on the surrounding groundwater since all the tun-
nels would be lined. The concerns addressed in the EIS included the
potential for contamination of the aquifer and the potential drawdown of
the local water table. The EIS concluded that there would be less than
300 gpm of inflow to the tunnels. This inflow would be reduced by tunnel
lining and grouting. It was also concluded that the drawdown of the aquifer
would be virtually zero due to operation of the tunnels. As far as exfil-
tration potential, it was determined that approximately 18 hours of
surcharged conditions (pressure greater inside tunnel) would occur with a
100 year storm. MSDGC proposed a monitoring program to "demonstrate that
the project is not causing contamination of the groundwater...."
The proposed program called for continuous level recording and quality samp-
ling for the following parameters: pH, BOD, Chlorides, Hardness, Alkalinity,
NH3-N, Total Phosporus, Phenol, COD, Cyanide, Mercury, Total Bacteria Plate
Count, Coliform, Fecal Coliform, Fecal Strep, Conductivity, and Total Sus-
pended Solids. Sampling would occur bi-weekly and after major storm events.
The monitoring wells would be installed at approximately 1/2 to 8/4 mile
intervals along the alignment at a minimum offset of thirty feet from the
tunnel edge. According to Figure 5-5 of the EIS, eight monitoring wells
were proposed by MSDGC.
0 Analysis of MSDGC Data
The analysis of the Upper Des Plaines system was based upon the following
documents:
0 Raw data reports from April 1985 - to September 1986 (Upper Des
Plaines System)
There are nine monitoring wells (See Figure 9) which were sampled bi-weekly
from April 1985 to September 1986. Only the raw data were presented to IEPA,
with no analysis of results. Upon inspection of the data sets there appeared
to be only two sample periods which indicated elevated fecal coliforms. The
MW-1 well on the "21" tunnel showed elevated fecal coliforms on October 10,
1985 and August 13-25, 1986. In addition, the water well levels do not ap-
pear to have either an upward or downward trend.
0 Recommendations
If MSDGC can document that the Upper Des Plaines system is operating at full
capacity and that potential exfiltration events have occurred, then analysis
of continuous level monitoring data for at least well MW-1 of the "21" Section
should be performed to evaluate the interconnection between the tunnel and the
aquifer. If this analysis shows the tunnel is interconnected, then additional
quality sampling based upon this relationship should be performed.
51
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FIGURE 9 TARP UPPER DES PLAINES MONITORING WELLS
BUFFALO GROVE
WHEELING
UPPER DES PIAINES 21
CONTRACT 73-320-2$
ARLINGTON
HEIGHTS
UPPER DES PIAINES 20A
Collection & lottrols
CONTRACT 73-318-2S
ROLLING
MEADOWS
MT. PROSPECT
UPPER DES PIAINES 20
Rock Tiuols I Drop Shifts
CONTRACT 73-317-2$
UPPER DES PLAINES 201
CONTRACT 73-319-2$
DES PLAINES
UPPER DES PIAINES 20C
CONTRACT 49-307-2$
UMIt MS
iisnvoii
ELK GROVE
Source:
TNI MITIOPOIITAN SANITAIT ftttTIICT
OP ORIATIt CNICAOO
INOINIIIINO OtPAITMNT
Monitoring well
52
-------
CALUMET
0 Proposed/Approved Monitoring Program
As was the case for the Mainstream and Upper Des Plaines tunnels, the EIS
(December, 1976) for the Calumet tunnels recommended a groundwater moni-
toring program to measure the effects of exfiltration and infiltration on
the surrounding groundwater. The EIS (p.X-7) recommended that the
monitoring wells be equipped with continuous level recorders to be used
for correlating aquifer pressure with tunnel pressure. The EIS also
recommended a quality sampling program for the monitoring wells. The
sampling of the wells was recommended to occur weekly and after major
storm events. As a minimum program, it was recommended that the follow-
ing parameters be measured on a weekly basis:
0 NH3 (as Nitrogen)
0 Total Bacteria Plate Count
0 Conductivity (or calculated TDS)
0 Total Organic Carbon
The EIS also indicated that the groundwater monitoring program would be a
grant condition (see Mainstream grant condition, p. 47) and would be ap-
pended to the Calumet Pumping Station O&M manual.
A monitoring program was developed by MSDGC in 1981. The September 1981
(revised July and August, 1983) Technical Report entitled, Groundwater
Monitoring Program Calumet Tunnel System - Crawford Ave. to Calumet
Plant, outlined MSDGC's proposed program.The proposed program included.
recording of groundwater levels along the alignments, periodic observa-
tion in tunnels to note infiltration locations, and quality sampling to
measure for exfiltration from the tunnels. The program would include:
eleven new level observation wells along the alignment; monitoring of
hydraulic grade line and pumpage records; and twp new quality sampling
wells.
All of the wells used during the pre-construction phase have been aban-
doned. Eleven new level wells were proposed to be located every 3500'
to 4000'. These wells would have piezometers to measure abrupt changes
in the groundwater level and would be monitored bi-weekly.
Two quality monitoring wells were included in the proposed program. The
two wells would be located in areas of expected exfiltration (areas of
unfavorable geologic conditions). The wells would be located downstream
of the tunnel, in the direction of groundwater flow and would be sampled
bi-weekly in accordance with USEPA's quality assurance procedures for
well flushing, sampling, and analysis (EPA 600/4-79-091). The wells
would include continuous water level recording and would be sampled for
pH, BOD5, Hardness, Alkalinity, N^-N, Total Phosporus, COD, Conductivity,
Total Suspended Solids and Fecal Coliform. The groundwater monitoring
reports would be sent to IEPA in a semi-annual basis.
The Calumet groundwater monitoring program was approved by USEPA in a
memorandum of December 6, 1983.
53
-------
0 Analysis of MSDGC Data
The analysis of the Calumet Tunnel System is based upon the following two
documents:
0 Groundwater Monitoring Program - Crawford Avenue to Calumet Plant
August 1983
0 Groundwater Monitoring Program - Crawford Avenue to Calumet STP
November 1986
There are two monitoring wells for groundwater quality and eleven monitor-
ing wells for water level measurements. These monitoring well locations
are depicted on the map in Figure 10. The sampling frequency was bi-weekly
plus additional samples during high water level conditions. The data
analysis presented in a November 1986 report was not very extensive and
did not attempt to determine if any interrelationships existed between the
various parameters evaluated. For example, the report stated there was not
a strong correlation between the tunnel water levels and the monitoring
well data or groundwater contaminants. However, the two do appear to be
related if one uses a lag in the well response. Though the wells are
equipped with continuous level recorders, exact lags could not be calculated
since well levels were only reported twice a month. See Figure 11 for the
correlation. More importantly there is a direct relationship between ele-
vated fecal coliforms and elevated well levels as shown in Figure 12. This
was also found to occur during the testing of the tunnel with river water,
when elevated fecal coliform levels were detected in a monitoring well
after a simulated surcharge condition. In addition, the hardness of the
groundwater increased during periods of high water while the alkalinity
usually decreased during the same periods. This is circumstantial evidence
that water from outside sources is entering the aquifer during these periods,
most likely due to exfiltration from the tunnel.
Recent data provided by MSDGC for the QC-2 monitoring well confirms the
conditions (specifically, the prolonged periods of elevated fecal coliform
levels), as discussed above. MSDGC has indicated that increased monitoring
will occur at the QC-2 well to determine the nature of the problems there
and to indicate the types of mitigation measures that may be necessary.
Several of the water level monitoring wells showed a decreasing trend. How-
ever the map provided did not identify specific monitoring wells, so the
area of the tunnel susceptable to infiltration is not readily apparent.
0 Recommendations
The MSDGC should perform a correlation analysis using the continuous level
recorder data for the QC-2 well to better define the lag time between high
water in the tunnel and the rise in the water well level. Clearly the
aquifer around the QC-2 well is experiencing some periodic contamination.
This phenomenon should be studied for a longer period of time to determine
if the change in water quality has any long term impacts.
The other wells should be monitoring for water levels to determine if the
downward trend will stabilize with time. If this trend continues, at least
one of these wells should be sampled for the water quality parameters,
especially if the well water level rises after major tunnel water rises.
54
-------
FIGURE 10 TARP CALUMET SYSTEM MONITORING WELLS
_l 0 I «
PHASE 1 TUNNEL
PHASE 2 TUNNEL
PHASE 1 TUNNEL COHPLETEO
PREVIOUSLY COMPLETED TUNNEL
PHASE 1 PUIPING STATION
PHASE 2 PUIPIN6 STATION
Monitoring well
Piezometer
-------
en
CTi
H
Lags in
tunnel
response time
to well
10
V"1
QC-2 WATER LEVELS
TUNNEL WATER LEVELS
"250
o
"tfo
f)
CD
CO
O
•/5t>
ro
m
73
'750
ELEVATION
3
i
-------
avo
2*0
3.90
QC-2 WATER LEVELS
tn
—i
HARDNESS
MG/L
LOG
IOOOO
1000
FECAL
COUNTS
loo
cr>
JO
o
i
INJ
200
ISO
100
I*
3»
- 0.0
_• i > i
_1 I I i i 1 I | i i i
• i i
"I to II
/ a
-------
OVERVIEW OF THE GROUNDNATER MONITORING PROGRAM
The sampling frequency for observation well water levels is bi-weekly,
although there are continuous level recorders on the quality wells whic.li
make measurements every 12 hours. Quality sampling was also taken bi-
weekly, and some attempts were made to sample after storm events of one
inch or greater. The sampling procedure of pumping the well dry and then
allowing the well to refill, was altered for some wells to allow for
optimum sampling. The continuous level data are retrieved every 3 months
and stored by computer, but are not reported to IEPA.
The amount of data available to make meaningful conclusions regarding the
trends in groundwater quality and piezometric head near the tunnel system
is not adequate. Though it appears that well water levels are decreasing
over time, more data are needed to determine if this is an impact of the
tunnels or a regional trend. For all three systems, the groundwater quality.
data should be taken for at least two successive years to determine if
there are any seasonal trends developing. Currently, the available data
only represent a year or less of system performance.
The groundwater monitoring network appears to have been designed to monitor
the areas most susceptable to exfiltration along the tunnel. Areas where
the geologic strata, principally dolomites, are interbedded and zones as-
sociated with areas of the tunnel which required significant grouting were
monitored for water levels and quality parameters.
However, many of these monitoring wells were finished in zones with little
fracturing. This is evidenced by the length of time (up to 48 hours) it
takes some wells to recover from pumping one well volume during the sampl-
ing procedure. These less fractured bedrock zones would not be as exposed
to exfiltrating water from the tunnel as other regions with more fractur-
ing, where water would tend to flow due to less flow resistance. It is
noted that even in these less fractured zones, groundwater contamination
was observed within one month of major storm events.
The presence of contaminated groundwater in Calumet well QC-2, which is 60
feet from the tunnel, occurs within one month of high water levels in the
Calumet tunnel. The flow velocity of the observed contaminated groundwater
is much greater than the predicted contaminant flow of 70 feet in 288 days,
as predicted by the Harza Engineering model in 1972. The QC-2 .well is fin-
ished in a less fractured zone and still has a relatively quick response,
as compared to predicted flow velocities. In order to properly assess the
extent of the contaminant flow, a model based upon flow in fractured bedrock
(the Harza model used a worst-case homogeneous permeability factor) would be
required. In addition to the modelling effort, a series of wells in a line
perpendicular to the axis of tunnel could be established at the QC-2 site
to assess the extent of the contaminant plume during exfiltration events.
In general, the data analysis provided by the MSDGC in the semi-annual
reports is cursory. Very little actual analysis of the data was performed.
The current analyses include only the development of summary tables and
58
-------
some plots of water levels. Even when this level of analysis was provided,
little discussion of the results was presented. For example, the Calumet
System data indicate water levels in most of the wells were decreasing with
time but the report did not discuss this trend. When episodes of high
fecal coliform contamination occured in some Mainstream system wells the
data was called "erratic...but not showing a net increase in contaminant
levels."
The lack of analysis of the other measured parameters such as Hardness,
Alkalinity, IDS, TSS and Chlorides indicates MSDGC did not make a serious
effort to identify other indicator parameters for combined sewer contamina-
tion. A more comprehensive data analysis could also provide information on
the general water quality of the aquifer system, if the data is compared
to wells finished in the same formations but away from the tunnel system.
CONCLUSIONS
The EIS's for the Mainstream, Calumet, and Upper Des Plaines TARP projects
called for groundwater monitoring to detect any adverse changes in the
groundwater in the vicinity of the tunnels. The purpose of the monitoring
would be to detect any alterations of groundwater due to infiltration or
exfiltration, and when necessary, to implement measures to mitigate any
adverse affects.
«
The EIS for Mainstream recommended that the monitoring wells and tunnels
be equipped with continuous water level recorders "... so that aquifer
pressure can be correlated with tunnel pressure," (EIS px-7). The EIS
also recommended bi-weekly sampling for quality data.
The monitoring program employed by MSDGC does collect the quality data
that the EIS recommends. Based on a review of the monitoring program
reports prepared by MSDGC, it is evident that the level of analysis of the
data is insufficient. The semi-annual reports prepared by MSDGC do not
reflect any attempt at correlation of tunnel pressure with aquifer pressure
data, as recommended by the EIS. This is extremely critical in attempting
to determine if there is an interconnection between the tunnels and the
aquifer.
A recent analysis conducted by MSDGC attempts to correlate tunnel level,
well levels and fecal coliform levels. This type of analysis should be
conducted for all the quality monitoring wells. Results of this type of
analysis can yield information about the lag times between surcharge events
and short term ground water contamination due to exfiltration and the re-
turn times during infiltration.
Since some wells are already equipped with continuous level recorders, the
12 hour interval data on these wells should be collected, plotted and
compared to the tunnel water levels in order to determine the degree of
59
-------
hydraulic interconnection between the tunnel system and the surrounding
geologic formations. In addition, rainfall events should be documented and
plotted so that aquifer recharge impacts can be evaluated.
The monitoring program data from all three systems indicate that there are
at least some episodes which produce contaminated groundwater near the TARP
tunnels. At this time there is not enough data to determine conclusively
if there will be a long term impact on the aquifer as a result of TARP
operation.
According to MSDGC, some periodic exfiltration is expected from normal opera-
tion of the tunnels. It was expected that after surcharge events the
exfiltrated water would return to the tunnels by infiltration. Apparently,
the tunnel systems are not being operated as designed. Specifically, the
tunnels are not being dewatered as quickly as originally predicted, thus
maintaining high water levels for longer periods of time.
It is likely that there are contamination zones forming along some stretches
of the tunnel system. The natural infiltration into the tunnel should mini-
mize the extent of the contamination zone. However, the current operation
of the tunnels allows for more exfiltration. Also, extreme exfiltration
events may enable contaminated water to travel outside the normal infiltra-
tion capture zone. This would allow contaminated water to travel beyond
the immediate tunnel area, especially in areas where there are more fractures
in the bedrock.
As was stated previously, the monitoring programs for TARP may be collect-
ing sufficient data to determine the potential for impacts to the aquifer.
The level of analysis (especially the lack of correlation analysis between
tunnel levels and well levels) conducted by MSDGC and reported to IEPA is
unsatisfactory. The purpose of the monitoring program was and is to col-
lect data for analysis to determine if the tunnel operation impacts the
aquifer, and if so, to take action to mitigate any regative impacts. Tunnel
level data and well level data (from the continuous recorders) must be ana-
lyzed for all monitoring wells to determine if there is an interconnection
between the tunnel and the aquifer. If a monitoring well shows an inter-
connection, additional quality sampling may be warranted to determine the
extent of the impact. With the MSDGC reporting on correlation analyses be-
tween the tunnels and wells to IEPA, the State can then make determinations
on the extent of additional quality sampling and/or mitigative measures which
may be warranted.
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CHAPTER 7
U.S. ARMY CORPS OF ENGINEERS STUDIES
The U.S. Army Corps of Engineers (CoE) has been involved in both the Phase I
and Phase II portions of the TARP project. The Phase I involvement of the
CoE has been primarily through the review and comment on plans and specifica-
tions f,or USEPA construction grants and by onsite overview during construc-
tion of these grant projects in accordance with the interagency agreement
between the CoE and the USEPA. The CoE has been more extensively involved
in the Phase II portion of TARP since the CoE has a national program which
provides funds for flood control projects. Due, in part, to the extensive
nature of the TARP project and flooding problems in the Chicago Area, Congress
authorized the CoE under Section 108 of the 1976 Water Resources Development
Act to prepare a Chicago Underflow Plan, Phase I General Design Memorandum.
The scope of this study consisted of a comprehensive analysis of the flooding
problems in the Chicago Metropolitan combined sewer area. This chapter will
discuss the potential impacts of the recently completed CoE Chicago Underflow
Plan Phase I General Design Memorandum documents conclusions on the TARP
Phase I system. Since the TARP project is designed to provide a combination
of pollution reduction and flood control benefits to the Chicago Metropolitan
Area; a document which proposes significant revisions to one aspect (flood
control) of the project could have an effect upon the other aspect (pollution
reduction). With this potential interrelated effect in mind, the recently
completed CoE documents were examined.
The CoE has completed the following two documents as part of the Chicago
Underflow Plan study:
1. Final Feasibility Report and Environmental Assessment;
Chicago Underflow Plan Phase I General Design Memoran-
dum; O'Hare System Interim Report: April 1984.
2. Feasibility Report and Environmental Assessment; Chicago
Underflow Plan Phase I General Design Memorandum:
December 1986.
These two reports contain a detailed feasibility study for the entire TARP
project (Upper Des Plaines, Des Plaines, Mainstream and Calumet Systems).
The CoE studies examined alternative flood damage reduction measures and
plans in order to identify the most cost-effective solution to the flooding
problems in the combined sewer area. Additionally, the studies identified
the Federal interest in the Phase II (flood control) portions of TARP. The
CoE evaluation yielded the following major conclusions:
0 Watercourse modifications, such as channel widening and deepening,
would have to be very extensive, would not be cost-effective, and
would cause significant adverse environmental and social impacts;
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0 Reservoir storage is best suited to reducing flood damages associated
with sewer outfall submergence which generally occurs during rain-
falls of long duration;
0 Sewer upgrading is generally best suited to reducing flood damages
associated with the high intensity, short duration storm events; and,
0 The use of check valves, stand pipes, and other flood proofing
measures is not well suited for regional application since these
measures transfer the problem to other areas, and may cause sewers
to burst or basement floors to crack due to the hydraulic pressure.
Based on the CoE analysis of alternative measures, it was further concluded
that:
0 A systematic, regional approach is needed to effectively reduce the
combined sewer back-up flooding problem;
0 Reservoir storage, in combination with the TARP Phase I tunnel systems,
is the most cost-effective measure for reducing flood damages caused
by submergence of the sewer outfalls due to inadequate watercourse
capacity;
0 Adding sewer upgrading to a basic reservoir plan, possibly in combina-
tion with temporary local ponding or in-line sewer storage in certain
areas, would further reduce sewer back-up flooding damages, however,
the local costs increase dramatically; and,
. ° Flood proofing devices such as overhead sewers and backflow regulators,
could be used by some homeowners on a selective basis, and with care,
to supplement the reservoir storage and sewer improvements, and further
reduce residual damages.
In April 1984, the interim CoE General Design Memorandum (GDM) was completed
on the O'Hare System. That report recommended Federal participation in the
construction of a 450 acre-foot floodwater storage reservoir to relieve
basement and street flooding due to outfall submergence along the watercourses
in the O'Hare System. The benefit-cost ratio was calculated to be 1.7. The
USEPA had no adverse comments to the interim GDM on the O'Hare System. A
larger 1,050 acre-foot O'Hare Reservoir was authorized by the Water Resources
Act of 1986 at an estimated cost of $18.4 million and a benefit-cost ratio of
1.0.
The Final CoE GDM recommends Federal participation in the construction of
two additional flood control reservoirs to relieve flooding in the Mainstream,
Des Plaines, and Calumet Systems. The CoE did reduce the sizing of the
McCook and Calumet Reservoirs, combined storage capacity at the reservoirs was
reduced from 124,000 acre-feet to 46,700 acre-feet and TARP Phase II tunneling
paralleling the Mainstream and Calumet Phase I tunnels was not recommended.
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The CoE report did not recommend a direct connection of the Lower Des
Plaines Tunnel to the reservoir, but rather suggests the use of the
Mainstream pumping station to achieve a 14-year - 24-hour rainfall event
level of protection. The Mainstream and Calumet systems would furnish
protection from flooding caused by anything less than a 50-year - 24-hour
storm event. The revisions, proposed by the CoE to the TARP Phase II
project will have no effect to TARP Phase I water pollution control ef-
ficiencies and only minor effects to the supplemental water pollution
benefits of the original TARP Phase II project which was proposed by the
MSDGC in its facilities plan.
The USEPA did forward comments of the final GDM concerning various elements
of the CoE plan which were generally addressed by the CoE (See Appendix 2).
The majority of USEPA comments dealt with concerns this Agency had during
the development of EIS documents for various components of TARP Phase I
(groundwater, blasting, odors) and these concerns should be addressed by
comprehensive programs based primarily upon experiences gained during the
first part of TARP Phase I construction and operation.
The general analysis and conclusions of the CoE GDM reports on TARP support
the basic assumptions of the USEPA approved facilities plan. As such, the
CoE GDM reports provide no reason to re-evaluate the basic assumptions and
plan for the remaining TARP Phase I components.
63
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CHAPTER 8
QUALITY BASEL INE
This chapter is currently under development. The completion of the
first draft of this chapter is now anticipated to be sent for comments
on April 30, 1988
64
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CHAPTER 9
SUMMARY
This chapter summarizes the more noteworthy findings revealed by USEPA's
examination of the constructed portion of TARP Phase I. For the most
part, each of the three systems has been constructed as designed. However,
the operation of the systems has been varied. The Upper Des Plaines TARP
system has been operating as designed but because of the circumstances at
the treatment plants and/or the geyersing problem, the Mainstream and
Calumet TARP systems operating procedures were revised.
The following are the major findings.
Upper Des Plaines TARP System
0 Major construction, maintenance and operational characteristics
are in accordance with design and planning documents. The system
accepts unrestricted sanitary sewage at all times, while combined
sewage is regulated by control structures on the combined sewer
outfalls.
0 Combined sewer overflow treatment does not cause significant de-
terioration of the O'Hare Water Reclamation Plant effluent. For
the period from June 1985 to December 1986, the average monthly
values for 6005, total suspended solids, or Ammonia - Nitrogen
met all NPDES permit limits.
0 Experience gained by control of odor problem from Upper Des
Plaines drop shaft vents will be utilized in the Lower Des
Plaines TARP system. Louvers were added to the Upper Des Plaines
system to control the flow of air and are designed into the
Lower Des Plaines system.
Mainstream TARP System
0 During the period of this study (October 1985 to December 1986)
31.464 billion gallons of stored combined sewage has been pumped
to the West-Southwest Wastewater Treatment Works from the Main-
stream TARP system.
0 . Major construction and maintenance characteristics are in accord-
ance with design documents. However, potential blasting damage
has become a controversial issue and must be thoroughly addressed
on future projects.
0 Under current operational procedures, a small amount of the first
flush of the combined sewage is discharged to the receiving stream
prior to diversion of the overflow into TARP.
0 TARP dewatering is controlled so that the flows to the treatment
plant are within design limitations, taking into account the
65
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extensive ongoing plant modifications. As a result of this con-
trol, effluent quality is not adversely affected though this
procedure partially limits storage capacity during extended.
rainfall events.
0 TARP filling procedures have been modified due to a geysering
problem. For rainfall events forecasted to be less than 1 inch,
all controlled TARP inlets are closed when tunnel is BOX full.
For rainfall forecasted to be greater than 1 inch, all controlled
inlets remain closed. The hydraulics of TARP are being modelled
in an effort to use the system more efficiently.
Calumet TARP System
0 Major construction and maintenance characteristics are in accord-
ance with design documents.
0 Due to an unforeseen delay in the Calumet Wastewater Treatment
plant improvement and expansion to 354 MGD from the present
236 MGD capacity (delay caused by contractor default), a substan-
tial portion (86%) of the flow from Calumet TARP was pumped
directly to the Little Calumet River from October 1985 to November
1986. The combined sewer overflow capture water in the Calumet
TARP system includes 3 to 5 million gallons per day of dry weather
sanitary sewer wastewater flow. This condition is considered to be
a temporary problem which will be remedied once the Calumet Treat-
ment plant is able to treat 354 MGD of flow.
Ground Uater Monitoring
0 The MSDGC ground water monitoring program consists of bi-weekly
monitoring of 9 monitoring wells on the Upper Des Plaines System,
25 observation and 17 water quality monitoring wells on the
Mainstream System, and 11 observation and 2 water quality moni-
toring wells on the Calumet System.
0 The MSDGC is utilizing Ground Water Monitoring Plans for each
TARP segment which were approved by IEPA and USEPA.
0 The groundwater monitoring data collected and reported by MSDGC
indicate some possible interconnection between the tunnels and
the aquifer.
0 Because the MSDGC data indicates that some ground water contamina-
tion is occurring, a more elaborate data analysis is necessary to
better assess the extent of the contamination. This data analysis
should be submitted as part of the semi-annual ground water moni-
toring report to IEPA and should include a graphical correlation
66
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analysis of the continuous well water level data with the tunnel
water level data to determine the lag times in the aquifer response
to surcharges. Once the lag times have been determined, quality
samples should be taken during subsequent storm events at the
proper lag time to determine maximum contamination levels. If the
contamination appears to be increasing with time, then a tunnel
exfiltration mitigation plan should be developed. Such a plan
could include regrouting of the tunnel segment, additional moni-
toring or other mutually agreeable solution.
U.S. Army Corps of Engineer Studies
0 The general analysis and conclusions of the recently completed General
Design Memorandum provided no reason to re-evaluate the basic assump-
tions and plan for the remaining TARP Phase I components.
Water Quality Baseline Report
0 This section is not scheduled for drafting until April 1988.
67
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APPENDICES
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APPENDIX NO. 1
BIBLIOGRAPHY
1) CHICAGO UNDERFLOW PLAN (CUP) - PHASE I, GENERAL DESIGN MEMORANDUM
by Department of the Army-Corps of Engineers - Chicago District, 1978.
2) CONSTRUCTION REPORT: VOLUME I - PROJECT ADMINISTRATION AND CONSTRUCITON
METHODS (Mainstream TARP) by Harza Engineering Company, May 1984.
3) CONSTRUCTION REPORT: VOLUME II - GEOLOGY AND HYDROLOGY (Mainstream
TARP) by Harza Engineering Company, May 1984.
4) Excerpts from O'HARE WATER RECLAMATION PLANT OPERATION AND MAINTENANCE
MANUAL - Raw Sewage Pump Operating Procedures, May 1984.
5) Excerpts from West - Southwest Wastewater Treatment Plant Operator's
Notebook.
6) FACILITIES PLANNING STUDY - O'HARE FACILITY AREA by Metropolitan
Sanitary District of Greater Chicago, revised January 1975.
7) FACILITIES PLANNING STUDY - SOUTH FACILITY AREA by Metropolitan
Sanitary District of Greater Chicago, revised January 1975.
8) FACILITIES PLANNING STUDY - OVERVIEW REPORT by Metropolitan Sanitary
District of Greater Chicago, revised January 1975.
9) FACILITIES PLANNING STUDY - UPDATE' SUPPLEMENT AND SUMMARY by Metro-
politan Sanitary District of Greater Chicago, May 1984.
10) FACILITIES PLANNING STUDY - UPDATE SUPPLEMENT AND SUMMARY ACTION PLAN
by John Variakojis and Bob Kuhl , Metropolitan Sanitary District of
Greater Chicago, May 1985.
11) FACILITY REVIEW OF CHICAGO PROJECTS by Paul D. Lanik, P.E., Burns &
Roe Industrial Services Corporation, May 1980.
12) FEASIBILITY REPORT AND ENVIRONMENTAL ASSESSMENT - CHICAGOLAND UNDERFLOW
PLAN, FINAL PHASE I, GENERAL DESIGN MEMORANDUM by Department of the
Army-Corps of Engineers - Chicago District, December 1986.
13) FINAL ENVIRONMENTAL IMPACT STATEMENT - METROPOLITAN SANITARY DISTRICT
OF GREATER CHICAGO O'HARE SERVICE AREA WASTEWATER CONVEYANCE SYSTEM,
by U.S. EPA, May 1975 (Draft: March 1975).
14) FINAL ENVIRONMENTAL IMPACT STATEMENT - TUNNEL COMPONENT OF THE TUNNEL
AND RESERVOIR PLAN PROPOSED BY THE METROPOLITAN SANITARY DISTRICT OF
GREATER CHICAGO - MAINSTREAM TUNNEL SYSTEM - 59TH STREET TO ADDISON
STREET by U.S. EPA, May 1976, (Draft: March 1976).
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APPENDIX NO. 1
2
15) FINAL ENVIRONMENTAL IMPACT STATEMENT - TUNNEL COMPONENT OF THE TUNNEL
AND RESERVOIR PLAN PROPOSED BY THE METROPOLITAN SANITARY DISTRICT OF
GREATER CHICAGO - CALUMET TUNNEL SYSTEM by U.S. EPA, December 1976,
(Draft: July 1976).
16) FINAL FEASIBILITY REPORT AND ENVIRONMENTAL ASSESSMENT - CHICAGO UNDER-
FLOW PLAN, PHASE I, GENERAL DESIGN MEMORANDUM by Department of the
Army-Corps of Engineers - Chicago District, April 1984.
17) GROUNDWATER MONITORING PROGRAM - CALUMET TUNNEL SYSTEM by Engineering
Department: Metropolitan Sanitary District of Greater Chicago, revised
August 1983.
18) GROUNDWATER MONITORING PROGRAM - MAINSTREAM TUNNEL SYSTEM by Engineering
Department: Metropolitan Sanitary District of Greater Chicago, revised
July 1983 (with Appendices A, B, C, and D).
19) GROUNDWATER MONITORING PROGRAM - TUNNEL AND RESERVOIR PLAN CALUMET
TUNNEL SYSTEM - CRAWFORD AVENUE TO THE CALUMET STP by J.R. Pivnicka
and L. S. Sakamoto, Tunnel and Reservoir Unit, Collection Facilities
Division, Engineering Department, Metropolitan Sanitary District of
Greater Chicago, November 1986.
20) GROUNDWATER MONITORING PROGRAM TUNNEL AND RESERVOIR PLAN MAINSTREAM
TUNNEL SYSTEM - ADDISON STREET TO 59TH STREET (Summary Report) by
J. R. Pivnicka and L. S.. Sakamoto, Tunnel and Reservoir Unit,
Collection Facilities Division, Engineering Department, Metropolitan
Sanitary District of Greater Chicago, December 1986.
21) GROUNDWATER MONITORING PROGRAM - TUNNEL AND RESERVOIR PLAN MAINSTREAM
TUNNEL SYSTEM - ADDISON STREET TO 59TH STREET (Supplemental Report)
by J. R. Pivnicka and L. S. Sakamoto, Tunnel and Reservoir Unit,
Collection Facilities Division, Engineering Department, Metropolitan
Sanitary District of Greater Chicago, April 1987.
22) HOW TO BOTTLE RAINSTORMS by Metropolitan Sanitary District of Greater
Chicago, April 1978.
23) MONITORING REPORTS FOR UPPER DES PLAINES from Raymond Doralek, MSDSGC
to Richard Carlson, IEPA, April 1985 to September 1986.
24) MONITORING WELLS - CHICAGO TARP by William Macaitis and Joe Sobanski,
Metropolitan Sanitary District of Greater Chicago, May 1985.
25) MONTHLY PLANT OPERATING DATA prepared by Operations and Maintenance
Department, Metropolitan Sanitary District of Greater Chicago,
June 1985 - December 1986.
26) OPERATION AND MAINTENANCE MANUAL (MAINSTREAM TARP) by Harza Engineering
Company, revised April 1985.
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APPENDIX NO. 1
27) OPERATIONAL PLAN - SUPPLEMENTAL TO OPERATION MANUALS - TUNNELS AND
RESERVOIR PLAN CALUMET SYSTEM by Keifer Engineering, Inc., March 1983.
28) RATE 6L LARGE GENERAL SERVICE from Commonwealth Edison Company,
October 29, 1985.
29) TARP GROUNDWATER MONITORING SUMMARY REPORT by Department of Research
and Development, Metropolitan Sanitary District of Greater Chicago,
Report No. 78-9, June 1978.
30) TARP REVIEW - REMAINING PHASE I by Metropolitan Sanitary District of
Greater Chicago, April 1980.
31) TARP UPPER DES PLAINES SYSTEM OPERATION AND MAINTENANCE MANUAL by
Collection Facilities Division, Engineering Department, Metropolitan
Sanitary District of Greater Chicago, April 1979.
32) FINAL ENVIRONMENTAL IMPACT STATEMENT - TUNNEL COMPONENT OF THE TUN-
NEL AND RESERVOIR PLAN PROPOSED BY METROPOLITAN SANITARY DISTRICT
OF GREATER CHICAGO - LOWER DES PLAINES TUNNEL SYSTEM by the U.S. EPA,
August 1977.
33) HANDBOOK FOR ANALYTICAL QUALITY CONTROL IN WATER AND WASTEWATER
LABORATORIES by U.S. EPA, (EPA 600/4-79-019).
34) RAW DATA REPORTS FROM APRIL 1985 to SEPTEMBER 1986 (UPPER DES PLAINES
SYSTEM) by Metropolitan Sanitary District of Greater Chicago.
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UNITED STATES ENVIRONMENTAL PROTEt TION ACENi V
liest»|iIMI»l*MOBNM
< Hit ACO. II.UNOI* MtM
&NF.-M
Colonel Frank I. Finch
District [nglneer
Department of the Army
Chicago District. Corps of Engineers
219 South Dearborn Street
Chicago. IMIiwU 60604-119)
Dear Colonel Finch:
In accordance with our responsibilities under the National Environmental
Policy Act (KM) and Section 309 of Uw Clean Air Act (CAA). the U.S.
U.S. t •« I r Mental Protection A«ency. leglo* S. has reviewed the
draft of the Final Phase I General Oe>l«n •taorandue (CON) on the
Chicago UnderfloM Plan (CUP). Hi also have reviewed the revised
M9es and report iweMry dated October IS. I9M. «htch Here tutelttcd
tuhseo^ently.
The report contains M (nvIronaenUI AtteiMent (CA) end Finding of
to Significant Intact (FNSI) for the proposed project, which recoancnds
the construction of t«o floodnater reservoirs. The reservoirs would
'J* he constructed at emitting rock quarries at NcCook and Thornton.
i— Illinois, to reduce hasoaent flooding In the Chicago Mtropol I tan
. ^
The storage capacity for the Mainstream System would be sufficient to -a
hold the runoff frem a SO-year. 24 -hour storm event. The storage m
allocated for the fees Plalnes System would be sufficient to hold the g
runoff frem • 14-year. 24 -hour event. ._,
x
The Calumet System reservoir would be co»>lne4 with a Congressional ly-
author I i*d U.S. Sell Conservation Service reservoir In the Thornton Quarry O
area. This reservoir would he designed to cental* 24.200 acre-feet
(I.* billion gallons) ef water to reduce overbank flooding In the tittle
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I.
Caluael River Basin. I he cuabinal ton .ol Hie two reservoirs into one
result In a significant cost savings, the storage voluae includes 4.600
acre-feel fur the Little Caluael River Basin and I4.6QQ acre-foel lor the
luoocl and Reservoir (IMP) Caluael SyUra. I he facility would provide
storage for runoff froa the 100-year flood event In. lh« little taluaet
River Basin and the ll-ye«r. 74-hour slora event In the Caluaet Systea.
Ihe reservoir would cover approalaately 129 *crti. and would be constructed
In t«o phases. The SCS portion would be constructed as soon as sufficient
floodwaler slorage c«p«clty bee Me available to accoaodale the I horn Creek
flood MOMS, through coaaerctal quarrying procedures. Ike second phase.
constructing the 1ARP Caluael Systea portion, would be begun alter th«
necessary *cre-fe«t of storage capacity becaae available through the saae
procedures. Both reservoirs would have connecting hydr«ultc structures, tn
•qutfer (trote
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-3-
ro
f) for the NilnstreM Tunnel does not eipllcltly
show such • connection. It does Include « description of common use of
the pumping station for dcvaterlng. The teit on pages V-ll. «-?«. and
V-8 of that EIS Implies that there Is gravity discharge from both systems
to the reservoirs. Because the Illinois Environmental Protection Agency
(lim) has Indicated that the Oes Plalnes Tunnel My be proceeding In
the near future, and USEPA will need to reevaluate the system under
current regulations; and because CQC Is relying In part on this previous
EIS. the cujter quality ratifications of using such • pumping system need
to be enplored prior to Issuance of the final version of the General
Design Memorandum. He understand that there could be a significant cost
savings If this step Is taken.
Ground Hater Quality
The Region 4 CISs Mere not conclusive In terms of beneficial, neutral, or
negative Impacts on ground Mter quality. Therefore, a ground water
monitoring system MS required, at well as back-up alligation Measures. In
the event that the Phase I tunnels contributed to or caused ground Mter
contamination. Because there Is the potential for eiflltratlon of MsteMter
from the proposed Phase II reservoirs Into the ground Mter. and because
the scaling technique to be used uould not apply to 100 percent of the
reservoir floors and Mils. M recommend that the Corps of Engineers develop
a ground Mter •onltorlng plan and mltlgatlve Matures. The •lltgatlve
measures would be used only If ground Mter contamination due to
operation of the Phase II reservoirs Is detected by means of the monitoring
system.
Blasting Mould be used to deepen the primary basins. COC has Indicated
that U.S. Bureau of Nines standards -III be followed. He support the use
of these standards. which M understand are more protective than those
used for the Phase I dropshafts. The use of those standards caused adverse
public reaction.
Odors
Several mechanisms are Identified In the final Design Memorandum to control
odors from the reservoirs. Paddle aerators would be Installed, and the
central basins would be MShed down after they are emptied. The solids from
these basins would be flushed to the Inlet/outlet structure and then
conveyed to the treatment plant. The solids In the primary basins Mould be
removed by means of a floating dredge, dewatered, and loaded Into trucks
for land disposal. He would like more Information on the methods to be
used for dewaterlng. loading the trucks, and land disposal. Because
ihe primary basins would not be emptied, aeration uould continue during
non-use periods.
Response
J. There will be no difference In the water quality bfiwMts attributable to
TABP Phase I. funded In-part by the USfPA. under a Phase I IARP pump station
operation as compared to a Phase ? IMP gravity fill operation. The flow fro*
the Phase I tunnels would pass through the pump station to the Meit-Southwest
Treatment Plant under either type of oepratton. There will be some reduction In
water quality benefits attributable to Phase ? IMP under the reco*me
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r\»
CM
ro
The 1911 EIS Indicated on page »-|Z that the Nest-Southwest treatment
facility needed to be eipanded to I.ISS nil I Ion gallons per day (mgd)
to eccamodate the Phase I project. The swmury provided by CDC did
not address the capacity required at the treatment plants to handle
the additional loadings. It also MS not made clear whether the
econoalct of the project provide for any additional treatment works.
or If the present design Makes use of off-peak capacity. These
topics should be addressed In the final Design NeaorenduB.
Me believe that the proposed project Mill provide significant water quality
benefits to the watercourses In the area, and that the Impacts froei the
construction and operation of the project will be dinar, of short duration,
and would not adversely affect human health or the environment. He have
no objection to the overall concept of the project. However, we do have
reservations, as Indicated In the previous paragraphs, regarding son* of
the design and operational details. Me would appreciate receiving the
additional Information we requested regarding these concerns. Also, If
there are any modifications proposed In the construction or operation
of the project as a result of cojemts received at the public meetings
or during the public comment period, we would appreciate being Informed
of these proposed changes.
Thank you for the opportunity to review the documents regarding this project.
If you have any questions regarding our comnents. please contact Ms. Kathleen
•rental of mj staff at FTS 886-18?) (commercial 112/RM-iBM) .
Sincerely yours.
UUIte* 0. Fran/. Chief
Environmental Review Branch
flaming and Management Division
Response
6. the capacity of the Hest-Southwest Treatment Plant will he Increased to
I.U8 mod In three stages of construction which will be sufficient to rtevater
the TWP tunnels. The Calumet facility Is he Ing expanded and upgraded to a
design capacity of )S4 mod which will acconwwlate dewatcrlng of the TMf tunnels.
This capacity Is equal to I.S times the average dry weather flow. Th« expansion
of the Calumet plant Is nearly completed. The designs of the recommended reser-
voirs are consistent with these treatment plant capacities. Ho further Increase
In treatment plant capacity will be required In connection with operation of the
reservoirs.
3=»
-o
m
•z.
o
X
o
•
ro
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APPENDIX NO. 3
Plan of Study
Tunnel and Reservoir Plan
Special Evaluation Project
86-2
Background - TARP Objectives and Current Status:
The development of the Tunnel and Reservoir Plan (TARP) began in mid-1960 and
culminated in 1972 with the Chicago Underflow Plan. The multi-purpose plan
was modified by the Metropolitan Sanitary District of Greater Chicago (MSDGC)
and renamed TARP, but its objectives remained as:
0 Control Flooding Impacts
0 Control Waterway Pollution Impacts
0 Eliminate Polluted Backflows to Lake Michigan
TARP's original planning was devoted to combined sewer overflow (CSO) impacts
and waterway capacities. Parallel planning was accomplished for wastewater
treatment needs. The distinction between the plans for flood and pollution
control was largely obscured due to the close integration of facilities. Con-
sequently, the title has evolved to embrace all of the flood (Phase II) and
pollution (Phase I) control elements.
Subsequently, between 1975 and 1984 the USEPA provided 972.7 million dollars
in funds for 19 TARP projects in the Upper Des Plaines, Lower Des Plaines,
Mainstream and Calumet TARP systems. The current status is summarized below:
System f Grants Grant Amount Status
Upper Des Plaines 4 $75.3 Operational/1982
Lower Des Plaines 1 $19.6 Under Construction
Mainstream 11 $759.3 Operational /1985
Calumet 3 $118.5 Operational /1986
Based on the TARP Phase I elements that are operational and the objectives of
the TARP Phase I, the USEPA Region V office has put together the following Plan
of Study.
Purpose^
This Special Evaluation Project (SEP) will provide an analysis of the con-
structed portion of TARP Phase I.
Specifically, SEP objectives will be directed:
1. To compile information on operation and design data pertaining to con-
ditions prior to construction of operational elements of TARP Phase I.
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APPENDIX NO. 3
- 2 -
2. To compile information on conditions pertaining to the actual construc-
tion and operational data of operational elements of TARP Phase I in-
cluding effects on ground water quality.
3. To compare and contrast the "design" and "operational" data.
4. To evaluate the effect of operation of the TARP Mainstream system on
indicators of water quality. The task of collection and analysis of
the information in the water quality portion of the study is extended
to allow time for the system to stabilize (particularly with respect to
existing benthic deposits) and respond to reduced input loads as identi-
fied on the attached extended project schedule (Page 7).
Scope;
The evaluation of TARP Phase I' operational elements will be separated into
three areas, with the examination focusing on different aspects of the
projects due to their unique characteristics.
Upper Des Plaines TARP
0 Historical aspects of the operation of the Upper Des Plaines TARP system,
focusing on correlations to current portions of other elements of the
system that are now operational.
0 Major construction, maintenance or operational characteristics.
Mainstream TARP (Focus of Region V effort)
0 Operational characteristics in relation to design parameters (Effective-
ness of wastewater capture).
0 Effects of operation on WWTP. (Note: Allowances will be made for on-
going WWTP construction.)
0 Major construction, maintenance or operational characteristics.
0 Water quality indicators will be assessed in an area that encompasses
portions of the Chicago waterways downstream and adjacent to the Main-
stream System, e.g., Northshore Channel, North Branch Chicago River,
Chicago River, South Branch Chicago River, Sanitary and Ship Canal, and
the Lower Des Plaines River.
0 The effects of TARP operation on Lake Michigan will also be assessed
within the context of backflow events and beach closures in the vicinity
of the Wilmette and Chicago Lock and Dams.
Calumet TARP
0 Major construction, maintenance or operational characteristics.
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APPENDIX NO. 3
- 3 -
Specific Study Questions;
1. What operational data are available for TARP?
2. Is TARP operating as designed?
3. Were problems encountered during construction?
4. What was the result of the problem and how was the problem resolved?
5. What performance data is available for wastewater treatment plant
operation prior to TARP dewatering?
6. What flows and loadings are coming out of TARP?
7. Does TARP dewatering significantly impact treatment plant performance?
8. Do recent COE reports on Phase II of TARP have any impact on the basic
assumptions inherent to constructing the remaining TARP Phase I compo-
nents?
9. Has the operation of Upper Des Plaines TARP identified areas of unex-
pected benefits or concerns?
10. Does a correlation ^exist between these benefits and concerns, (see 9.
above) and any other TARP construction?
11. Has TARP affected the number of backflows to Lake Michigan?
12. Will operation of TARP influence future water quality and biological
conditions in the Chicago River waterways?
13. What records and facilities are available as part of the TARP Phase I
ground water monitoring program?
14. Do the general water records show any interconnection between the tunnel
system and the aquifer.
15. Does the TARP ground water monitoring program effectively monitor poten-
tial ground water contamination?
16. Will TARP influence the frequency of backflow events (and consequently
beach .closures) in Lake Michigan?
Work Description for Water Quality Studies
0 The water quality analysis is designed to review, evaluate and analyze past,
current and future data collection results related to specific water qual-
ity indicators.
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APPENDIX NO. 3
. 4 -
0 Water quality indicators of potential biological, chemical and physical
influences from TARP Mainstream operation will consist of:
- Biological parameters including fish, benthic macroinvertebrate and
phytoplankton community structure, and bacteriological quality;
- Chemical parameters including D.O., BODs, NH3-N, TKN, IDS, TSS, SOD,
volatile solids, metals, turbidity;
- Historical and ongoing records relating to backflow events and beach
closures.
Q To examine the influence of other factors which may affect water quality,
correlation analyses will be analyzed between water quality parameters and:
- River discharge/diversion data;
- Rainfall/runoff information;
- Municipal treatment plant inputs; and
- Combined sewer overflow inputs.
0 Specific outputs will include:
- Baseline Water Quality Report and documentation of analytical methods
for ongoing data collection efforts, September, 1987;
- Interim Water Quality Report (1986 - 1987), September, 1988;
- Water Quality Report (1986 - 1989), September, 1990.
Specific Information Sources (in addition to USEPA files):
Metropolitan Sanitary District of Greater Chicago (main information source) -
0 Examination and compilation of available data regarding the operation of
the TARP Phase I system and related treatment plants.
0 Observations of officials who oversaw construction, design and operation/
maintenance of the project.
0 Description of ground water monitoring systems and data reports.
0 Detailed results and analyses of chemical, physical, and biological
monitoring in Chicago River Waterways (historic and ongoing efforts).
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APPENDIX NO. 3
- 5 -
U.S. Army Corps of Engineers -
0 Examination of any COE files for information pertaining to TARP start-up.
0 Examination of potentially related general design memorandum.
0 Examination of related environmental documents prepared by the COE con-
cerning TARP.
0 Observations of project managers.
Illinois Environmental Protection Agency -
0 Examination of grants and permits files.
0 Observations of project managers, Grants Administration Section coordina-
tors, Permits Section and Planning personnel.
U.S. Geological Survey -
0 Potential use of results from a 3.5 year pilot water quality study of
the upper Illinois River basin.
USEPA Responsibilities
Valdis Aistars
Noel Kohl
Ernesto Lopez
James Luey
Russell Martin
Thomas Poy
Charles Pycha
David Siebert
0 COE Coordinator.
0 Calumet TARP focus.
0 Team Leader, Water Quality Branch.
0 Mainstream TARP focus.
0 Water Quality Standards.
0 Team Leader, Municipal Facilities Branch
(MSDGC Contact).
0 Project scheduling, coordination and report.
0 Upper Des Plaines TARP focus.
0 MSDGC planning and design focus.
0 IEPA Coordinator.
0 Mainstream TARP focus.
0 Ground Water focus.
0 Contact for Office of Ground Water. '
Scheduling; See pages 6 and 7.
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00
oi
Begin to
Develop
Draft POS
WQB
TARP SPECIAL EVALUATION PROJEC
Jegln to
Develop
Draft POS
MFB
b
Complete
MFB
Portion
Draft POS
SCHEDULE
Complete
WQB
Portion
Draft POS
Complete POS
Data Gathering
&
Analysis
Complete POS
Data Gathering
&
Analysis
MSDGC/IEPA
Input/Review
\
A .•
• i
Draft
Report
MFB
)raft
Jasellne
(Report
WQB
TnaT
Jasellne
Report
WQB
USEPA
Internal
Technical
Report
Final
Report
MFB
Region V
Baseline WQ
&
Facility
Operation
Report
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APPENDIX NO. 3
WQB
FY 87 Data Collection
Baseline
- 7 -
LONG-RANGE TARP SCHEDULE
MFB
Data Collection and analysis
of Operational TARP systems
FY 88 WQ Data Collection
Interim Report
FY 89 WQ Data Collection
Supplemental report based on
fully operational Calumet WWTP
Supplemental report based on
fully operational West-Southwest
WWTP.
FY 90 TAPR Interim WQ
Improvement Reprot
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