ILLINOIS POLLUTION CONTROL BOARD
November
29,
1988
IN THE MATTER OF:
)
PETITION OF THE VILLAGE OF
)
PCB 85-213
WESTERN SPRINGS FOR EXCEPTION
)
TO THE COMBINED SEWER OVERFLOW
)
REGULATIONS
)
OPINION AND ORDER OF THE BOARD
(by B. Forcade):
This matter
is before
the Board on the December
26,
1985
Section 306.364, 35 Ill. Adm. Code 306.363
(1983),
single
petition* of
the Village
of Western Springs
(“Village”).
The
petition requests relief from Section 306.305(a)
and
(b), which
would otherwise require
treatment or retention of
a portion of
the Village’s combined sewer overflows
(“CSOs”)
now entering
Flagg Creek.
The Board issued
a
“more information order”
on
January
9,
1986, noting
a deficiency
in the petition.
The
Village filed
its amended petition on March 11,
1986.
The
Illinois Environmental Protection Agency
(“Agency”)
filed its
appearance on September 22,
1986.
The public hearing occurred June
10, l988,** and one member
of the public attended.
The Village filed its Brief on August
30,
1988.
The Agency filed
a response brief
on September
16,
1988.
The Village filed
its reply brief instanter on September
26,
1988.
An affidavit accompanied
the Village reply brief,
which the Village refiled
in a duly executed form on October
3.
I.
Background
The Village is
a suburb of Chicago, has
a population of
about 12,900 persons,
and lies on a total of about 1550 acres.
The Village has been fully developed for about 20 years,
so its
population has remained fairly stable since that time.
The
Village operates
its own sewer s~’stem, which spans portions of
*
The Village
of Western Springs typed
the December
26 petition
as
a Section 306.363 joint petition.
The Agency did not join in
the petition,
R.
5
&
13, and now challenges
the relief sought.
Further,
the record does not indicate that the Agency proposed an
exception to the Village.
See Section 306.360.
For these
reasons,
the Board deems the Village’s petition
a single
petition.
**
The Board delayed hearings
in
this matter due
to
a shortage of
available funds.
See Order
of February
6,
1986.
93—627
—2—
two drainage basis:
the Salt Creek basin,
about 550 acres,
and
the Flagg Creek basin,
about 1000 acres.
The Salt Creek basin
combined sewers discharge
to the Tunnel and Reservoir Plan
(“TARP”)
of the Metropolitan Sanitary District
of Greater Chicago
(“MSD”).
R.
10;
Ex.
6,
pp.
1—1 to 1—2.
The CSO discharges from
a portion of the Flagg Creek basin are the focus of
this
proceeding.
About 1,800 persons
in 600 houses
reside in this
portion of the Village.
Ex.
5, Att.
L;
Ex.
6,
p.. 3—6.
The Village comprises several sewer drainage areas.
See
Ex.
9.
Portions of Areas
5 and
6 are involved in this proceeding.
Both are north of 47th Street
in the Flagg Creek basin.
Both are
excluded from the TARP system.
Area
5 drains a total
of 89
acres, of which 24 acres have separate storm and sanitary sewers
along 47th Street and Wolf Road.
The separated storm water
discharges to Flagg Creek.
65 acres of Area
5 have combined
sewers.
R.
11,
16—17,
22,
43
& 51—52;
Ex.
6,
pp.
3—1 to
3—2.
Area
6 drained
95 acres of combined sewers,
and had
39 acres
of separate storm sewers
in Spring Rock Park and along
the
Burlington
& Northern railroad tracks at the time the Village
studied its CSOs and subsequently filed
its petition for
a CSO
exception.
At that time,
the total CSO drainage area
in Areas
5
and
6 was 160 acres.
In mid—1986, the Village began separating
sewers
in Area
6,
and completed this project by installing about
4,500 lineal feet of storm sewers at
a cost of about $900,000 for
the separation of the sewers
in
58 acres
of this Area.
This
resulted
in a 36 percent reduction in the combined sewered area
subject to this proceeding,
to about 102 acres.
Area
6 now has
37 acres
of combined sewers.
R.
11,
22,
31—32,
51,
53
&
60; Ex.
2, pp.
3
&
7;
Ex.
4;
Ex.
5,
pp.
11—13.
Area
5 combined sewers drain
into the Fair Elms manhole at
the intersection of 47th Street and Fair Elms Avenue.
Area
6
combined sewers discharge into the 47th Street manhole, which
is
adjacent
to the Fair Elms manhole at that intersection.
Both
manholes interconnect and collectively discharge into the Fair
Elms sewer.
That sewer runs due south
to the intersection of
55th Street and Fair Elms Avenue,~where
it discharges to a MSD
interceptor that runs west beneath 55th Street.
R.
11,
43
& 52;
Ex.
2,
pp.
7
&
12;
Ex.
5, Att.
L.
The estimated dry weather
flows from Areas
5 and
6 are 0.17 and 0.15 cubic feet per second
(“cfs”),
respectively.
The measured flows
are 0.12 and 0.44
cfs,
respectively.
R.
54;
Ex.
2,
p.
7;
Ex.
6,
p.
3—7.
The MSD
interceptor at 55th Street has
a maximum carrying capacity of 6.8
cfs,
but the MSD installed an additional interceptor
in 1987,
which increases this to about
17
cfs.
R.
18—19
& 62;
Ex.
4;
Ex.
5,
p.
13.
The Village has an additional restriction
in the Fair
Elms sewer
that limits the combined discharges from ~reas
5 and
6
to 6.4 cfs when the system surcharges.
R.
54
& 81—82;
Ex.
2,
p.
42.
The aggregated
1720 home drainage areas of the Village south
of 47th Street, and therefore south of Areas
5 and
6, are on a
93—628
—3—
separated sewer system.
R.
11
&
52;
Ex.
2,
p.
7;
Ex.
5,
ktt.
L.
Areas
5 and
6 are apparently the only local combined sewage
areas
not included in TARP.
R.
52.
During periods
of heavy rain that result
in CSO events,
the
flows from Areas
5 and 6 increase until
the Fair Elms sewer
becomes surcharged.
At that point,
the maximum rate
of discharge
from the Fair Elms manhole at 47th Street
is limited to 6.4
cfs.
The Fair Elms manhole, which drains Area 5,
has
a diversion
outlet 3.32 feet above the outlet into the Fair Elms sewer.
The
47th Street manhole, which drains Area 6, hasa diversion outlet
1.33 feet above
the normal outlet to the Fair Elms manhole.
The
47th Street manhole diversion outlet
is 0.19 foot higher than
that of the Fair Elms manhole.
Ex.
2,
p.
12; but see Ex.
5, Att.
L (giving slightly different elevations).
Additional
flows cause
the sewage levels
in the 47th Street and Fair Elms manholes
to
rise until
they reach the diversion structure
in these
manholes.
Diverted sewage goes
to a common CSO discharge
structure
at 49th Street and Flagg Creek.
R.
11
&
52;
Ex.
2,
pp.
3
&
7.
The Village would consider increasing the height of these
diversion structures,
in order
to increase the volume
of
retention in
its sewers,
as part of the relief
in this
proceeding——so long
as this retention and the concomitant sewage
backup does
not cause basement or street flooding.
R.
19;
Ex.
4.
James
E.
Huff investigated the Village’s CSOs to determine
the volume of first flush of the Areas
5 and
6 sewers.*
During
the period Mr.
Huff studied
the Village’s CSO,
four rain events
occurred.
The sewers captured all the first flush from three
CSOs,
and 94.5 percent of the fourth.
Ex.
2,
pp.
17,
19,
23,
27,
31
&
36.
At the time of his study,
Mr. Huff determined the mean
first flush was 260,000 gallons based on the then existing 160
acres of combined sewers
in Areas
5 and
6.
The observed first
flush volumes ranged from 160,000
to 290,000 gallons.
The
average first
flush contained 454 pounds
of biochemical oxygen
demands
(“BOD5”),
for an average concentration of
209 milligrams
per liter
(“mg/i”);
1,509 pounds of total suspended solids
(“TSS”),
for an average of concentration of 733 mg/l;
and 847
pounds of volatile suspended solids,
for an average concentration
of 391 mg/i.
Mr. Huff estimated that the Village captured 95
percent of the first flush volume per annum,
or 96.4 percent of
the BOD5 and 96.3 percent of the TSS.
R.
54—55;
Ex.
2,
pp.
37
&
45.
*
First flush
is the volume of water and associated flow rate
necessary to carry away
the excess biochemical oxygen demand and
solids accumulated
in the sewers during dry weather periods until
their concentrations diminish
to those of dry weather flows.
35
Ill. Adm. Code 375.102
(1985);
see R.
54;
Ex.
2,
p.
3.
93—62Q
—4—
Mr. Huff now estimates
that the intervening sewer separa—
tions
reduced the combined sewered area by about 36 percent,
increased
the volume captured
to 97 percent, reduced
the amount
of BODç lost by 51 percent,
and reduced TSS loss by 61 percent.
R.
59—60;
Ex.
4.
This would mean that the average rate of 80D5
capture increased to 98.2 percent,
and the average rate of TSS
capture increased to 97.7 percent.
He further estimates that the
Village now captures 100 percent of the first flush for an
estimated 43 of the 47 CSO events that would occur
in a year.
R.
61.
Mr. Huff studied Flagg Creek and concluded that
the
Village’s CSO
at 49th Street has no noticeable effect on the
creek.
The Agency concurs
in his assessment.
R.
110
&
118.
Mr.
Huff determined that this CSO did not apparently affect water
quality as determined by macroinvertebrate diversity.
He
attributed
the trend towards increasing diversity downstream to
increasing
stream flow.
R.
55—56;
Ex.
2,
p.
42.
Upstream and
downstream sediment samples showed no sewage sediments and
contained low levels
of volatile solids.
R.
56—57;
Ex.
2,
p.
42.
Testing for metals and oil and grease*
in the sediments
showed
no upstream or downstream trend.
R.
57—58;
Ex.
2,
p.
42.
Following one rain event during the study period,
for which
there was full capture, Mr. Huff observed wastewater—associated
debris on the banks for about 100 yards,
a “sheen” on the water
in more stagnant areas,
and a septic odor immediately downstream
of the Village’s CSO discharge.
He observed a more pronounced
septic odor and a greater quantity of sewage—related debris for
150 feet downstream from the MSD CSO.
These are the only
observed potential CSO effects,
and the Village received no
complaints about this or any other effects.
R.
61; Ex.
2,
p.
60.
The Agency observed even less impact when it conducted
a
more limited inspection of the stream.
R. 116—17.
Mr.
Huff estimated that during the storm event which
resulted
in the greatest volume of first
flush during the study
period,** the Village CSO discharged 600,000 gallons into Fiagg
Creek.
Based on the measured average flow of 108 million gallons
per day (“MGD”)
at a downstream U.S. Geological Survey station,
he estimated that the average flow at 49th Street was about
30
MGD
at the time of this discharge.
This translates
to
a 50:1
dilution ratio
in the stream for this CSO.
R.
59.
*
A single high oil and grease sample came from where
runoff
enters the stream from
a tollway oasis parking lot.
R.
58.
**
This storm of October
18,
1985 dropped 2.32 inches
of rain and
had
a maximum intensity of 1.26 inches
in one hour.
Ex.
2,
pp.
17
&
22—24;
see
R.
59.
fl3—630
—5—
Flagg Creek
is heavily channelized, with
a 10—foot wooded
bank separating it from the residential land on the east and with
the toliway on the west.
The primary stream use is for urban
drainage, and Mr.
Huff observed no indication of recreational
use.
R.
58—59;
Ex.
2,
pp.
6,
53
&
55.
The stream has
its origin
in Hinsdale, has
a total length of 7.5 miles,
and drains into the
Des Plaines River.
Its depth ranged from four to 30
inches
within the three mile length studied by Huff,
and its width
ranged from nine to 49 feet.
Ex.
2,
pp.
53—56.
Its origin
is
slightly over half a mile from the Village CSO.
It receives
several stormwater discharges; effluent,
including treatment
plant bypasses, from the Hinsdale Sanitary District
(over two
miles downstream);
and CSO effluent from the MSD (about one—half
mile downstream).
Mr.
Huff felt
these facts,
combined with
its intermittent
nature,
limited potential uses for Flagg Creek.
R.
58;
Ex.
2,
p.
55.
He believes that the total elimination of
the Village’s
CSOs,
by total sewer separation in Areas
5 and 6, would not
result
in
a measurable improvement
in stream water quality or
a
change in the potential stream
uses.
R.
64.
The Agency agrees
that the Village’s CSO presently has no identifiable impact on
Flagg Creek.
R.
117.
The record indicates control alternatives available to the
Village,
the costs associated with some of these,
and problems
associated with others.
The costs
of completing
the separation
of Areas
5 and
6 sewers to eliminate the CSO
is estimated as
$2,550,000.
The cost of
the partial separation already
accomplished
in Area
6 was $900,000.
R.
32—33;
Ex.
4.
The cost
of
improving the transport capacity to TARP
is estimated at
$2,600,000,
but the MSD drop shaft in that area lacks
the
capacity
to accept the additional
flows from Areas
5 and
6.
R.
16—17, 22
&
26.
In Mr. Huff’s opinion, the least—cost
alternative for elimination of the CSO
is the construction of
a
90,000 gallon retention reservoir, with some provision
for later
pumping the sewage back into the sewers.
This would increase the
volume of first flush captured.
The costs associated with this
alternative are $300,000,
exclusi’ve
of the cost of land
acquisition,
and have
a $3,500 annual operating cost.
R.
62—63,
65—66
&
85—86;
Ex.
2,
p.
42.
The Village currently owns
no land
on which
to locate a retention facility,
R.
22,
but a potential
area exists
in
a local park.
R.
66.
This location, however,
might present odor problems
if used for such
a facility.
R.
67.
Other alternatives arose
in testimony given at the public
hearing, without any estimates of their associated costs.
The
first alternative involves increasing
the transport capacity
in
the Fair Elms sewer
to 55th Street and the MSD system.
Mr. Huff
testified this would likely eliminate Village CSOs,
but would
also
likely increase those occurring from the MSD CSO at 55th
Street.
R.
81—82
& 105—106.
The other alternative
is one which
.3—631
—6—
would only reduce the CSO volumes discharged, but
it would not
eliminate them.
This is the alternative the Village has offered
to perform as part of
the relief sought:
the Village could raise
the inverts of the 47th Street and Fair Elms Avenue diversion
structures.
This would increase the degree of sewer surcharging
necessary to trigger
a CSO, thus increasing the amount of
retention by the system.
This alternative could result
in some
Street and basement backups
if the invert is raised too high.
However,
the extent of
its practicability and effectiveness are
not indicated in the record.
R.
19;
Ex.
4.
Although the MSD CSOs at 55th Street have no direct
relevance to the Village,
the subject of those CSOs has arisen
throughout this proceeding.
It
is therefore useful to outline a
few facts pertinent
to them before discussing the merits of the
respective Village and Agency arguments.
The MSD CSO diversion structure is located near where the
Village’s Fair Elms sewer discharges
to the MSD.
Ex.
5, Att.
L.
The MSD diversion structure has four staged pumps.
The first
two turn on when the MSD interceptor first begins
to surcharge,
and these divert overflows
to the TARP system.
The second two
turn on at higher levels of sewer surcharging, and
they divert
CSO effluent
to Flagg Creek.
Ex.
5, Att.
K—M.
Historically,
the
second two pumps operated about 20 hours each year.
Since the
1987 construction of the additional MSD interceptor,
an
approximately 60 percent reduction in MSD CSOs has occurred.
The
pumps now operate about 8.3 hours each year.
R. 62
& 69—70.
Although the Village contributes combined sewage
to the MSD CSOs,
it
is not the sole contributor.
The LaGrange Highland Sanitary
District also contributes wastewater,
as possibly do other
areas.
R.
81,
84
&
113; Ex.
5,
Att.
L.
II.
Discussion
The Agency challenges
the requested CSO relief.
In its
post—hearing brief,
the Agency challenges relief from Section
306.305(b)
as unwarranted because the Village’s sewers capture
ten times
their design and ten
ti’mes their dry weather flows,
see
35
Ill.
Adm.
Code 306.305(b), so the only
issue involved
is the
Section 306.305(a)
first
flush capture.
Agency Response at
1.
The Agency then challenges any relief whatsoever because the
effect
of the village’s flow on
the MSD CSOs
is uncertain based
on this record.
Agency Response at
2.
The Agency more fully
expressed
its concerns at hearing.
In its review of
the Village’s CSO for
this proceeding,
the
Agency became aware
of the relationship between the Village CSOs,
the Village sewer system,
the discharges
to the MSD, and the MSD
CSOs.
The Agency corresponded with the MSD on this point,
and
submitted copies of some such correspondence into the record.
See Ex.
10.
The MSD apparently intended
to reduce tributary
93—632
—7—
flows into
its interceptor and eventually eliminate
its CSO
diversions.
R.
95.
The following exchange occurred on the
record at hearing:
Agency
witness:
The
concern
thiat
the
Agency
has
in
regard
to
this
proceeding
is
that
it
did
not
appear
that
a
grant
of
an
exception,
to
the extent that the Village had
requested
it,
would
allow
MSD
to
accomplish
that
task
and,
therefore,
we
would
have
no
compliance
plan
anymore
for
MSD’is
CSOI
outfall
141.
Agency
attorney:
When
you
say
the
MSD
compliance plan was reducing the excess flows,
in
the
case
of
Western
Springs
who
would
actually do the work
of reducing the flows?
(Agency witness):
Western Springs.
R.
95—96
The Agency’s witness later testified in response
to questions by
the Village that the Village’s CSOs are dependent on transport to
the MSD:
“Obviously
one could increase the transport capacity
past the current overflow and,
therefore,
either decrease or
eliminate the Village’s overflow.”
R.
106.
As
to the Agency’s expressed concern that granting the
Village
relief will affect MSD’s compliance plans
for its 55th
Street CSO discharges,
the Board will not deny relief on this
basis.
The MSD did not participate
in this proceeding and its
CSO discharges are not involved.
The only issues relevant here
are the impact of the Village’s CSOs and the costs and
practicability of controlling
them.
It
is on these issues that
the Board must focus.
The record suggests that the Village’s options for
compliance with Section 306.305 are the total elimination of its
CSOs,
by construction of
separate storm sewers
at
a cost of over
$2.5 million,
or the full capture of the first flush,
by
construction of
a retention facility at
a cost
of over
$300,000.
The record does not suggest that the third alternative
of
raising the diversion inverts
in the 47th Street and Fair Elms
manholes would result
in full compliance,
although this would
probably increase the rate of first flush capture.
The initial
issue with regard to Village compliance
is the full capture of
its first
flushes,
see R.
118; Agency Response at
1,
and the
construction of retention facilities
is the least—cost
alternative
for compliance,
so
it
is the $300,000 cost upon which
the Board will focus.
93—633
—8—
The record nowhere indicates that full capture of
first
flush would result in an improvement in stream water quality and
potential uses.
Rather,
it suggests that the Village’s CSOs
currently have
no cognizable impact on the stream.
Thus,
the
record indicates that requiring the Village
to spend $300,000 to
fully comply with Section 306.305 would confer little or no
environmental benefit.
Therefore, the imposition of this expense
is presently not justified based on this record.
The Board will
therefore grant the requested relief as it applies
to the volume
of first flush capture, under Section 306.305(a).
The next issue relates to the requested relief from Section
306.305(b), upon which the Agency seems to more specifically
focus
in its response brief.
Section 306.305 provides
in
significant part as follows:
All
combined
sewer
overflows
...
shall
be
given
sufficient
treatment
to
prevent
pollution,
or
the
violation
of
applicable
water
quality
standards
unless
an
exception
has been granted by the Board
Sufficient
treatment
shall
consist
of
the
following:
(b)
Additional
flows,
as
determined
by
the
Agency
but
not
less
than
ten
times
the
average
dry
weather
flow
for
the
design year,
shall
receive
a minimum
of
primary
treatment
and
disinfection
with
adequate retention time
35 Ill. Adm. Code 306.305
(1987).
Subsection
b,
therefore, would require the Village to retain,
in
addition to dry weather flows,
a minimum of ten times the average
dry weather flow, which
is about~5.6cfs,* or such additional
flows as the Agency has determined are necessary “to prevent
pollution,
or the violation of applicable water quality
standards.”
There
is no argument that the Village’s sewers
currently retain “ten times the average dry weather flow for the
design year” for eventual treatment by the MSD.
The Agency has
not argued that any treatment of “aidditional
flows”
is
necessary at this time.
Therefore,
the Village
is
in compliance
with subsection
b,
and there
is no need for the Board to grant
relief from this subsection.
~ See supra page
2
(indicating an aggregated dry weather flow of
0.56 cfs for Areas
5 and 6).
93—634
—9—
In summary,
the record supports
a grant of relief under Part
306, Subpart D,
35 Ill.
Adm. Code 306.350—306.374
(1987),
from
subsection
a
of Section 306.305 of
the Board’s CSO
rules. The
Board
finds that
“the existing physical conditions,
the character
of the area involved,
including the character
of surrounding land
uses,
zoning classifications,
the nature
of the existing
receiving body
of water,
...
and the technical feasibility and
economic reasonableness
of
...
reducing the particular type
of
pollution
involved”
in the Village’s CSOs,
Ill.
Rev.
Stat.
ch.
111—1/2,
par.
1027(a)
(1988);
see 35
111.
Adm. Code 306.371(a)
(1987),
support
the grant of this
relief.
The Agency has
presented
no cognizable arguments that would support
a denial
of
this relief
in light of the record before the Board.
On the
other hand,
relief from subsection b of Section 306.305
is
unwarranted because the Village
is
in compliance with that
subsection.
Section 41 of
the Environmental Protection Act,
Ill.
Rev.
Stat.
1985,
ch.
111—1/2, par.
1041, provides for appeal
of final
Orders
of the Board within
35 days.
The Rules
of the Supreme
Court
of Illinois establish filing requirements.
ORDER
The Village
of Western Springs
is hereby granted
an
exception from subsection
a of Section 306.305
of the Board’s
Water Pollution rules.
As
a condition
to the above exception, Western Springs shall
raise the overflow inverts
in the manholes at
the intersection
of
47th Street and Fair Elms Avenue, which discharge combined sewage
to Flagg Creek,
to the maximum elevation that will
not result
in
sewage backups
into basements and/or street flooding.
IT
IS SO ORDERED
Board Member Joan Anderson abstained.
I, Dorothy M.
Gunn,
Clerk of the Illinois Pollution Control
Board,
hereby certify
that the
a
o
e Opinion and Order was
adopted on
the
~
day
of ________________________,
1988,
by
a
orothy M. ,~mn, Clerk
Illinois P&llution Control Board
q3—635
