Document ID: EPA-HQ-OW-2003-0074-0636
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2003-12-24T05:00Z

1
BACKGROUND
INFORMATION
4
Water
Quality
Concerns
4
Beneficial
Uses
Affected
4
Slough
Hydrology
and
Segmentation
4
Available
Monitoring
Data
5
DISSOLVED
OXYGEN
8
Water
Quality
Criteria
8
Monitoring
8
Modeling
9
Loading
Capacity
Defined
10
Allocations
12
Implementation
Strategy
14
Airport
storm
water
permit
14
Designated
Management
Agencies
15
Industrial
storm
water
permits
16
New
discharges
16
EUTROPHICATION
(
PH
AND
NUTRIENTS)
16
Water
Quality
Criteria
16
Monitoring
17
Modeling
21
Loading
Capacity
and
Margin
of
Safety
Defined
22
Allocations
23
Implementation
Strategy
24
BACTERIA
26
Water
Quality
Criteria
26
Monitoring
27
Data
Analysis
27
Margin
of
Safety
29
Loading
Capacity
Defined
29
2
Allocations
30
Implementation
Strategy
30
TOXICS
31
Water
Quality
Criteria
31
Pb
Monitoring
33
Instream
data
33
Loading
Capacity
and
Margin
of
Safety
Defined
35
Allocations
36
Implementation
Strategy
39
Industrial
permittee
requirements
40
Environmental
Cleanup
Sites
40
Designated
Management
Agencies
41
Organics
Monitoring
41
Fish
tissue
sampling
41
Loading
Capacity
Defined
42
Allocations
43
Implementation
Strategy
44
Industrial
Storm
water
permits
45
Environmental
Cleanup
Sites
45
Designated
Management
Agencies
45
REFERENCES
46
TEMPERATURE
ANALYSIS
49
Water
Quality
Criteria
49
Monitoring
49
Modeling
49
CONVERSION
FACTORS
51
3
Columbia
Slough
TMDLs
WQ
Concerns
at
a
Glance:

Water
Quality
Limited?
Yes
Segment
#
22P­
COLSO,
mouth
to
Fairview
Lake
Water
Quality
Standards:
Willamette
Basin,
OAR
340­
41­
442,
OAR
340­
41­
445
Parameters
with
Season
Water
Quality
Limited:
Bacteria
­
annual
pH
­
spring
through
fall
dissolved
oxygen
(
cool
water
aquatic
life)
­
annual
chlorophyll
a
­
spring
through
fall
phosphorus­
spring
through
fall
temperature
­
spring
through
fall
Pb
­
water
column
DDE,
DDT
­
fish
tissue
PCBs­
fish
tissue
2,3,7,8
TCDD
­
fish
tissue
dieldrin
­
fish
tissue
(
preventative
TMDL)
Uses
Affected:
Salmonid
fish
rearing,
resident
fish
and
aquatic
life,
wildlife
and
hunting,
fishing,
boating,
water
contact
recreation,
aesthetic
quality
Known
Sources:
Industrial
discharges,
combined
sewer
overflows,
groundwater,
urban
storm
water,
landfill
leachate,
airport
de­
icing,
clean
up
sites
Suspected
Sources:
Sediments,
agricultural
runoff,
failing
septage
fields,
air
deposition
Water
quality
in
the
Columbia
Slough
is
affected
in
a
complex
manner
by
sources
such
as
combined
sewer
overflow
events,
groundwater,
landfill
leachate,
airport
de­
icing
fluids,
urban
runoff,
past
practices
and
industrial
runoff,
as
well
as
conventional
National
Permit
Discharge
Elimination
System
(
NPDES)
point
sources.
The
Total
Maximum
Daily
Load
(
TMDL)
strategy
will
be
to
identify
the
loading
capacity
of
the
Slough
for
the
pollutants
of
concern
and
implement
a
water
quality
management
plan
(
WQMP)
to
control
the
identified
sources
and
achieve
the
TMDLs.
The
WQMP
will
incorporate
load
allocations
and
waste
load
allocations,
water
level
management
and
implementation
of
storm
water
Best
Management
Practices
(
BMPs).
The
TMDL
will
utilize
a
phased
approach
through
which
the
effectiveness
of
controls
will
be
assessed
with
a
monitoring
program
and
additional
controls
required
if
waste
loads,
loads
and
TMDLs
are
not
being
achieved.
The
controls
will
be
implemented
via
Memorandums
Of
Agreement
(
MOAs)
with
the
designated
management
agencies
(
DMAs).
For
most
of
the
Municipal
Separate
Storm
Sewer
System
(
MS4)
permit
holders
the
permit
incorporates
the
agreements
in
the
MOAs
as
a
permit
condition.
Requirements
for
urban
storm
water
control
for
Multnomah
County,
however,
will
be
implemented
via
revisions
to
their
MS4
permits
since
their
permit
does
not
incorporate
the
TMDL
requirements
of
the
MOA.
4
BACKGROUND
INFORMATION
The
Columbia
Slough
is
a
19
mile
long
complex
of
narrow
and
shallow
channels
located
on
the
southern
floodplain
of
the
Columbia
River
between
Fairview
Lake
and
the
Willamette
River.
The
Slough
was
originally
a
series
of
wetlands
and
marshes;
it
is
now
a
highly
managed
water
system
with
dikes
and
pumps
to
provide
watershed
drainage
and
flood
control
for
the
lowlands
surrounding
it.
The
management
of
the
Slough
can
have
a
significant
impact
on
the
water
quality
and
uses
supported
by
the
Slough.
The
Slough
drains
approximately
40,000
acres
of
land.
Many
kinds
of
land
use
are
found
within
the
watershed
including
heavy
and
light
industries,
residential
areas,
vegetable
farming
and
the
Portland
International
Airport.
The
Slough
also
serves
as
one
of
the
City's
largest
open
space
and
wildlife
habitat
areas.

Water
Quality
Concerns
The
Columbia
Slough,
from
the
mouth
to
Fairview
Lake,
has
been
placed
on
DEQ's
1994/
1996
303(
d)
list
for
multiple
parameters.
The
Slough
is
water
quality
limited
for
chlorophyll
a,
pH
and
phosphorus
from
spring
through
fall,
because
of
algal
growth.
This
algal
growth
affects
the
aesthetic
quality
of
the
Slough
and
may
affect
such
beneficial
uses
as
fishing
and
boating.
The
dissolved
oxygen
criteria
for
cool
water
aquatic
life
is
violated
throughout
the
year;
diurnal
swings
in
dissolved
oxygen
during
the
summer
months
are
most
likely
the
result
of
algal
growth,
while
winter
violations
are
likely
due
to
storm
water
runoff,
including
de­
icing
fluid.
These
dissolved
oxygen
criteria
violations
may
prevent
the
Slough
from
supporting
salmonid
fish
rearing
as
well
as
resident
fish
and
aquatic
life.
Elevated
bacteria
levels
through
all
seasons
impact
the
water
contact
recreation
use
(
swimming).
In
the
spring
through
fall,
high
temperatures
are
also
a
concern,
affecting
salmonid
fish
rearing.
The
Slough
is
water
quality
limited
for
DDE,
DDT,
PCBs
and
dioxin
due
to
elevated
levels
found
in
fish
tissue,
impairing
the
use
of
the
Slough
for
fishing.
The
State
of
Oregon
Health
Division
and
the
City
of
Portland
have
issued
recommendations
against
eating
fish
from
the
Slough
due
to
contamination
by
PCBs,
DDE
and
DDT.
Review
of
data
also
indicates
that
dieldrin
is
present
in
fish
tissue
at
elevated
levels.
The
Slough
is
water
quality
limited
for
lead
(
Pb)
because
of
levels
above
the
fresh
water
chronic
criteria
for
the
protection
of
aquatic
life.

Beneficial
Uses
Affected
The
affected
beneficial
uses
for
the
Columbia
Slough,
as
identified
in
Oregon
Administrative
Rules,
include
salmonid
fish
rearing,
resident
fish
and
aquatic
life,
fishing,
hunting,
boating,
water
contact
recreation
and
aesthetic
quality.

Slough
Hydrology
and
Segmentation
The
Slough
has
been
divided
into
five
reaches
(
Figure
1,
CH2MHill,
1995),
based
primarily
on
hydraulic
characteristics.
The
reaches
of
the
Slough
are
generally
shallow
with
variable
widths.
5
The
Lower
Slough
(
Reach
1)
extends
from
the
Willamette
River
to
the
Multnomah
County
Drainage
District
Pump
Station
No.
1
at
NE
13th
Avenue
(
MCDD1)
and
includes
the
North
Slough.
The
Lower
Slough
is
tidally
influenced,
so
the
water
quality
in
the
Lower
Slough
is
heavily
influenced
by
that
in
the
Willamette
River.
At
MCDD1
there
is
a
dike
that
physically
separates
the
Lower
and
Middle
Sloughs.
Potential
sources
of
pollutants
to
Reach
1
include
sediments,
combined
sewer
overflow
events,
groundwater,
storm
water,
leachate
from
St.
Johns
landfill,
industrial
discharges,
and
water
from
Reach
2
and
the
Willamette
River.
The
Middle
Slough
(
Reach
2)
extends
from
MCDD1
to
a
cross
levee
(
mid­
dike)
which
has
slide
gates
that
can
hydraulically
isolate
flows
between
the
Middle
and
Upper
Sloughs.
About
half
the
annual
flow
in
the
Middle
Slough
is
due
to
groundwater.
Potential
sources
of
pollutants
to
Reach
2
include
sediments,
groundwater,
storm
water,
illicit
discharges,
and
contamination
from
the
NuWay
Oil
Site
and
water
from
Reach
3.
The
Upper
Slough
(
Reach
3)
extends
from
the
mid­
dike
to
the
outlet
of
Fairview
Lake.
The
Upper
Slough
receives
considerably
less
groundwater
than
the
Middle
Slough.
West
of
Four
Corners,
the
Slough
is
subject
to
reversal
of
flows
due
to
the
operations
of
the
Multnomah
County
Drainage
District
Pump
Station
No.
4
(
MCDD4)
located
on
Marine
Drive.
MCDD4
discharges
directly
to
the
Columbia
River.
The
arm
of
the
Slough
to
MCDD4
often
has
little
or
no
flow
exchange
with
other
portions
of
the
reach.
During
the
summer
it
is
basically
a
stagnant
waterbody.
The
Middle
and
Upper
Slough
are
not
driven
by
tidal
influences
or
affected
by
CSO
discharges.
The
system
hydraulics
are
influenced
by
the
MCDD
pump
stations
and
inflow
of
groundwater.
Potential
sources
of
pollutants
include
sediments,
groundwater,
storm
water,
industrial
discharges
and
water
from
Reach
4.
Fairview
Lake
(
Reach
4)
is
a
shallow
lake
that
covers
about
105
acres.
The
lake
is
not
considered
part
of
the
Slough,
but
contributes
to
the
flow
of
the
Slough.
During
the
summer
months,
however,
flow
from
Fairview
Lake
to
the
Upper
Slough
is
negligible
compared
to
the
flow
from
groundwater
(
CH2MHill,
Part
2,
1995).
The
flow
from
Reach
5
(
Fairview
Lake
drainage
basin,
not
pictured)
includes
the
tributaries
of
Fairview
Lake,
which
are
composed
of
Fairview
Creek,
Osborn
Creek,
and
No
Name
Creek.
This
reach
is
not
part
of
the
Slough,
but
it
discharges
to
Fairview
Lake.

Available
Monitoring
Data
The
Columbia
Slough
has
been
monitored
sporadically.
Metropolitan
Service
District
(
METRO)
has
been
conducting
water
quality
monitoring
near
St.
John's
landfill
in
the
Lower
Slough
since
the
1970'
s.
Portland
State
University
(
PSU)
conducted
water
quality
monitoring
in
1992­
1994
for
dissolved
oxygen
(
DO),
temperature
and
pH.
The
City
of
Portland
Bureau
of
Environmental
Services
(
BES)
has
conducted
monitoring
in
the
Slough
since
1992,
including
hydrolab
data
for
pH,
temperature
and
DO.
Additional
water
quality
monitoring
has
been
conducted
by
the
City
of
Gresham
and
the
US
Environmental
Protection
Agency
(
EPA).
Toxics
data
for
the
Columbia
Slough
includes
water
column
data,
fish
tissue
data
and
sediment
data.
Toxics
for
which
the
Slough
is
routinely
monitored
include
the
following
metals:
cadmium,
chromium,
copper,
nickel
and
lead.
Most
of
the
fish
tissue
data
available
for
the
Columbia
Slough
was
collected
as
part
of
the
Screening
Level
Risk
Assessment
done
on
Slough
sediments
as
part
of
the
Sediment
Remediation
Project.
As
part
of
this
study,
fish
and
crayfish
were
collected
during
the
summer
of
1994
at
10
different
locations
in
the
Columbia
Slough,
and
tested
6
for
110
different
chemicals.
Historical
fish
tissue
data
was
collected
by
DEQ
as
part
of
a
larger
investigation
of
the
Lower
Willamette
River.
The
following
sections
discuss
the
results
of
monitoring
of
the
Slough,
and
the
allocations
and
strategies
developed
to
attain
water
quality
standards
for
each
303(
d)
list
parameter.
7
Figure
1:
Columbia
Slough
8
DISSOLVED
OXYGEN
Water
Quality
Criteria
Dissolved
oxygen
(
DO)
is
important
for
maintaining
a
healthy
and
balanced
distribution
of
aquatic
life.
Salmonid
species
are
the
most
sensitive
beneficial
use
affected
by
dissolved
oxygen
concentration.
For
waterbodies,
such
as
the
Columbia
Slough,
identified
by
the
Department
of
Environmental
Quality
(
DEQ)
as
providing
cool
water
aquatic
life,
the
dissolved
oxygen
must
not
be
less
than
6.5
mg/
L.
When
DEQ
determines
that
adequate
information
exists,
the
dissolved
oxygen
may
not
fall
below
6.5
mg/
L
as
a
30­
day
mean
minimum,
5.0
mg/
L
as
a
seven
day
minimum
mean,
and
may
not
fall
below
4.0
mg/
L
as
an
absolute
minimum
(
OAR
340
­
41­
445).

Monitoring
Synoptic
water
quality
data
show
DO
criteria
violations
throughout
the
Slough.
During
winter,
DO
criteria
violations
occur
frequently
and
the
DO
concentrations
are
the
lowest
in
the
Lower
Slough
and
the
main
stem
of
the
Middle
Slough.
During
the
winters
of
1990
­
1994
there
were
frequent
exceedances
of
the
DO
criteria
at
reaches
2A
and
1B
(
CH2MHill,
Part
1,
1995).
A
severe
DO
depletion
problem
was
recorded
in
February
1995
in
the
Middle
and
Lower
Slough.
DO
in
the
Lower
Slough
was
recorded
as
zero
for
almost
two
days.
This
severe
oxygen
depletion
occurred
after
a
severe
winter
storm
hit
Portland
on
February
12th,
1995.
Significant
snow
and
ice
accumulation
lasted
until
February
15th
or
16th.
Portland
International
Airport
(
PDX)
used
de­
icing
and
anti­
icing
chemicals
(
ethylene
glycol
and
urea)
with
high
BOD
(
biochemical
oxygen
demand)
values
during
this
time
period.
The
severe
oxygen
depletion
appears
to
be
a
result
of
the
de­
icing
activities
(
Wells
1995).
The
dissolved
oxygen
sag
in
the
Lower
Slough,
at
the
St.
John's
landfill
bridge
(
SJB),
is
presented
graphically
in
Figure
2:

February
95,
DO
sag
site
SJB
0
2
4
6
8
10
12
15­
Feb
16­
Feb
17­
Feb
18­
Feb
19­
Feb
20­
Feb
21­
Feb
22­
Feb
23­
Feb
Date
DO
mg/
L
Figure
2:
February
95
Dissolved
Oxygen
Lower
Slough
9
Another
incident
of
dissolved
oxygen
depression
occurred
during
February
1996.
The
DO
was
below
4
mg/
L
for
almost
10
days
at
the
North
Denver
Bridge
(
NDB)
in
the
Lower
Slough.
This
DO
drop
occurred
after
about
8
days
of
freezing
weather.
At
MCDD1
(
main
stem,
Middle
Slough)
DO
concentrations
were
below
4
mg/
L
for
about
3
days.
No
impacts
of
depressed
dissolved
oxygen
were
seen
above
the
airport's
discharge
at
NE
92
ND
,
NE
158
Th.,
nor
at
MCDD4
(
main
stem,
Upper
Slough)
(
Wells,
1996).
This
data
suggest
de­
icing
and
anti­
icing
loads
dominate
the
BOD
load
to
the
Slough,
resulting
in
oxygen
standard
violations
with
anoxic
conditions.
There
are
limited
DO
data
available
for
Reaches
2B,
2C
and
2D
during
the
winter
months.
Data
from
Reach
3
did
not
indicate
any
water
quality
problems
related
to
DO
(
CH2MHill,
Part
1,
1995).
Summer
violations
of
the
DO
criteria
occur
much
less
frequently
than
winter
violations
and
may
be
due
to
stagnant
water
and
algal
processes.
Because
the
DO
criteria
violations
which
occur
in
the
summer
appear
to
be
caused
by
algal
processes,
they
are
addressed
in
the
eutrophication
section.
The
following
discussions
of
modeling
efforts,
loading
capacity
and
implementation
strategy
only
address
the
winter
dissolved
oxygen
criteria
violations.

Modeling
A
water
quality
model
has
been
used
to
estimate
the
effects
of
winter
weather
and
wet
weather
loads,
particularly
from
Combined
Sewer
Overflows
(
CSOs)
and
storm
water.
The
water
quality
and
hydrodynamics
model
is
an
adaptation
of
the
Corps
of
Engineers'
model
CE­
QUAL­
W2
(
Corps
of
Engineers,
1986,
1990;
Cole
and
Buchak,
1994).
Event
based
pollutant
loads
from
storm
water
were
estimated,
including
de­
icing
loads
from
PDX.
Model
calibration
is
described
in
Wells,
1995.

Modeling
conclusions:
 
The
major
components
affecting
DO
in
Reach
1
are
upstream
discharges
from
Reach
2,
storm
water,
CSOs
and
sediment
oxygen
demands.
 
De­
icing
materials
from
PDX
contribute
to
severe
oxygen
depletion
in
the
Middle
and
Lower
Slough
in
the
late
fall
and
winter.
 
De­
icing
loads
from
PDX
will
have
to
be
reduced
significantly
to
meet
dissolved
oxygen
criteria
in
the
Slough
(
Wells,
October
1996).
 
Flood
events
in
the
Willamette
and/
or
Columbia
River
worsen
the
oxygen
depression
because
they
stagnate
the
water
in
the
Lower
Slough
(
Wells,
October
1996).

Monitoring
data
has
indicated
that
low
DO
levels
in
the
Slough
are
of
concern
primarily
in
the
winter
months.
Because
of
this,
the
loading
capacity
and
allocations
will
be
defined
for
the
wet
weather
BOD
loads
only.
Data
analysis
and
modeling
has
demonstrated
that
de­
icing
and
anti­
icing
activities
at
PDX
are
the
dominant
source
of
BOD
to
the
Slough.
Anoxic
conditions
are
observed
in
the
Slough
when
de­
icing
and
anti­
icing
loads
are
coupled
with
stagnant
water
conditions.
Model
calibration
by
Wells
(
1995)
indicates
that
the
BOD
load
from
urban
runoff
is
less
than
1/
2
the
concentration
reported
in
the
municipal
separate
storm
sewer
(
MS4)
permits.
The
implementation
strategy
will
require
the
DMAs
to
refine
estimates
of
the
BOD
load
to
the
Slough
and
the
effect
on
water
quality.
The
strategy
will
also
require
PDX
to
reduce
the
de­
icing
and
anti­
icing
load.
10
Loading
Capacity
Defined
The
ambient
DO
criteria
concentration
is
used
to
determine
the
loading
capacity
(
LC)
of
the
Slough
for
BOD
materials.
The
LC
is
expressed
as
an
ultimate
biochemical
oxygen
demand.
The
BOD
LC
is
dependent
on
the
deoxygenation
(
Kd)
and
aeration
(
Ka)
rate.
The
resulting
load
allocations
are
for
the
winter
months
of
November
through
March.
Allocations
are
not
defined
for
BOD
loads
during
the
summer
months.
Analysis
of
data
provided
by
Union
Carbide
and
PDX
resulted
in
a
range
of
possible
Kd
values
for
the
Slough.
Values
for
Ka
were
calculated
using
the
Banks
and
Herrera
formula
using
wind
speed
and
waterbody
depth.
See
Appendix
B
for
a
detailed
description
of
this
analysis.
Once
the
appropriate
Ka
and
Kd
values
were
chosen,
a
dissolved
oxygen
balance
(
Streeter
Phelps
equation)
was
used
to
determine
a
range
of
ultimate
BOD
(
Lo)
that
would
result
in
the
attainment
of
the
DO
criteria
of
6.5,
5.0
and
4.0
mg/
L
DO.
The
Streeter
Phelps
equation
is
given
as
:

(
)
(
)
[
]
(
)
(
)]
[
]
D
K
K
K
K
t
K
t
L
C
C
K
t
d
a
d
d
a
o
s
a
=
 
 
 
 






+
 
 
exp
exp
exp
0
Where:
D
=
DO
deficit
(
mg/
L)
Lo
=
instream
BOD
(
BOD
ultimate)
(
mg/
L)
Kd
=
decay
rate
(/
day)
Cs
=
DO
at
saturation
(
mg/
L)
Ka
=
aeration
rate
(/
day)
Co
=
DO
initial
(
mg/
L)
t
=
time
(
days)

(
Thomann
et
al,
1987)

The
Streeter­
Phelps
equation
contains
several
assumptions;
there
is
one
dominant
source
of
BOD,
DO
of
a
stream
is
unaffected
by
nitrification
and
algal
respiration,
replacement
of
oxygen
is
affected
by
reaeration
and
not
by
algal
photosynthesis,
there
are
steady
state
conditions
along
the
river
channel.
During
the
winter
months,
when
de­
icing
influences
water
quality,
algal
photosynthesis
processes
will
be
negligible.
PDX
has
stopped
using
urea
in
its
de­
icing
operations,
so
nitrification
is
not
a
significant
BOD
load.
In
response
to
comments
from
PDX,
the
oxygen
analysis
was
expanded
to
include
dispersion.
Dispersion
acts
to
spread
the
plug
of
high
strength
BOD
out
as
it
moves
down
the
Slough.
By
adding
dispersion
it
was
no
longer
assumed
that
the
discharge
was
continuous
or
that
steady
state
conditions
exist.
The
de­
icing
discharge
was
assumed
to
occur
for
1
day
per
event.
Dispersion
is
represented
by
the
following
equation
(
Chapra,
1997):

E
U
B
H
gHS
x
=
0
011
2
2
.

where:
Ex
=
longitudinal
dispersion
coefficient
(
m2/
s)
U
=
velocity
(
m/
s)
B
=
width
(
m)
H
=
depth
(
m)
11
g
=
acceleration
due
to
gravity
(
m/
s2)
s
=
channel
slope
(
dimension
less)

A
one
dimensional
dissolved
oxygen
model
was
used
(
LTI,
July,
1997)
to
represent
the
influence
of
dispersion
on
the
Streeter
Phelps
model
predictions.
The
model
divided
the
Columbia
Slough
into
a
one
dimensional
series
of
completely
mixed
reactors
of
constant
volume.
The
model
solves
two
differential
mass
balance
equations;
one
each
for
BOD
and
DO.
Conditions
in
the
Lower
Slough
appear
critical
because
this
is
where
the
BOD
plug
can
stagnate
when
the
Willamette
flows
are
high.
The
BOD
calculations
simulated
conditions
as
measured
in
the
field
when
the
anoxic
DO
levels
were
recorded;
temperatures
were
near
8
°
C.
The
five
day
BOD
(
BOD5
)
limits
should
be
expressed
in
the
terms
that
they
would
be
measured
at
the
laboratory,
at
standard
temperature
of
20
°
C.
The
laboratory
measure,
and
TMDL,
will
be
presented
as
BOD5.
The
conversion
is
made
in
a
two
step
process
that
is
consistent
with
how
the
samples
would
be
handled.
First
the
BOD
sample
is
taken
from
the
field
to
the
laboratory
and
allowed
to
equilibrate
to
20
°
C
which
increases
the
decay
rate
and
is
represented
as:
k
k
T
T
=
 
20
20
 
(
Tchobanoglous
et
al,
1985).
By
rearrangement,
k
k
T
T
20
20
=
 
 
.
The
temperature
adjustment
factor
(
 )
is
1.102.
The
calculations
to
determine
 
are
contained
in
Appendix
B.

The
BODu
is
then
converted
to
BOD5
by
the
following
equation:
BODt
=
BODu(
1­
e­
kt)
Where:
t=
time,
5
days
k
=
the
decay
rate,
at
20
°
C
(
Tchobanoglous
et
al,
1985)

The
loading
capacity
was
calculated
using
the
following
equation:
LC
=
(
Q)(
BOD5)(
conversion
factor)
Where:
Q
=
river
flow
in
cubic
meters/
second
(
m3/
sec)
BOD5
=
calculated
BOD5
in
mg/
L
conversion
factor
=
to
convert
from
m3/
sec
and
mg/
L
to
kg/
day
A
portion
of
the
loading
capacity
is
set
aside
as
the
margin
of
safety
(
MOS).
The
margin
of
safety
accounts
for
the
uncertainty
about
the
relationship
between
pollutant
loads
and
water
quality
of
the
receiving
water.
A
baseflow
of
1.98
m3/
sec
(
groundwater
flow
only)
and
storm
flows
are
used
to
calculate
the
loading
capacity.
The
storm
flows
range
from
2.83­
11.33
m3/
sec,
approximating
the
range
of
flows
achieved
by
pumping
at
MCDD1.
The
results
of
this
analysis
are
summarized
in
Table
1.
12
Table
1:
BOD5
Loading
Capacity
The
DO
water
quality
criteria
has
three
tiers
to
recognize
that
the
effect
of
reduced
DO
on
fish
and
aquatic
life
is
dependent
on
how
low
the
DO
gets
as
well
as
the
duration
and
frequency
of
the
low
DO.
Since
the
sources
are
non
steady
state
pulse
loads
from
runoff,
the
LC
is
identified
for
three
specific
conditions;
an
hourly
maximum
BOD
load
based
on
achieving
the
minimum
DO
criteria
(
4.0
mg/
L),
an
event
daily
average
maximum
based
on
achieving
the
7­
day
mean
minimum
DO
criteria
(
5.0
mg/
L),
and
a
long
term
continuous
average
based
on
achieving
the
30­
day
mean
minimum
DO
criteria
(
6.5
mg/
L).

Allocations
The
TMDL
is
a
matrix
of
flows
and
associated
average,
daily
average
maximum
and
hourly
maximum
BOD5.
The
LC
is
distributed
between
the
dominant
sources
of
oxygen
demanding
material,
which
include
PDX
de­
icing
and
urban
runoff.
The
background
(
BKG)
BOD5
concentration
is
set
to
2.5
mg/
L
(
Appendix
B).
The
WLA
for
CSOs
is
zero
(
except
for
a
one
in
five
year
winter
storm
and
one
in
ten
year
summer
storm).
A
margin
of
safety
(
MOS)
is
set
at
20%
of
the
total
BOD5
load
at
each
flow
for
each
DO
criteria
(
Appendix
B).
The
distribution
between
airport
and
urban
runoff
is
based
on
a
percent
reduction
equivalent
to
the
relative
contribution
to
the
observed
DO
deficit.
Modeling
results
from
Wells
(
1995,
EWR­
2­
95)
were
used
to
estimate
the
contributions.
The
modeling
used
measured
discharge,
DO,
temperature
and
limited
instream
BOD.
Storm
water
and
de­
icing
BOD
loads
were
adjusted
to
fit
the
measured
data.
This
calibration
effort
indicated
that
de­
icing
and
anti­
icing
loads
contribute
3.8
lb.
of
BOD
load
for
every
1
pound
of
urban
storm
water
BOD.
The
waste
load
allocations
incorporate
the
ratio
of
3.8
lb/
1
lb
de­
icing
and
anti­
icing
load
removed
to
urban
storm
water
removed.
The
loading
capacity
is
therefore
defined
as:

LC
=
QCbkg
+
QCmos
+
QCsw
+
QC
de­
icing
where:
Flow,
m3/
sec
DO
criteria
(
mg/
L)
LC
(
BODu,
mg/
L)
LC
(
BOD5,
mg/
L)
LC
(
kg/
day)
MOS
(
kg/
day)
LC
and
MOS
to
meet
4.0
mg/
L
DO
criteria
2.83
4
48
24
5947
1189
5.66
4
64
33
16108
3222
8.5
4
61
31
22842
4568
11.33
4
69
35
34583
6917
LC
and
MOS
to
meet
5
mg/
L
DO
criteria
2.83
5
41
21
5170
1034
5.66
5
56
28
13893
2779
8.5
5
53
27
19920
3984
11.33
5
60
31
30262
6052
LC
and
MOS
to
meet
6.5
mg/
L
DO
criteria
2.83
6.5
32
16
4004
801
5.66
6.5
42
22
10571
2114
8.5
6.5
41
21
15537
3107
11.33
6.5
48
24
23782
4756
13
C
sw(
WLA)
=
Cso(
1­
 )
or
the
concentration
of
the
storm
water
in
the
waste
load
allocation
is
equal
to
the
initial
storm
water
concentration
times
the
reduction
needed
and:
C
de­
icing(
WLA)=
C
de­
icingo(
1­
 b),
b=
3.8
or
the
de­
icing
waste
load
allocation
is
a
function
of
the
initial
de­
icing
concentration,
the
reduction
needed
and
the
ratio
between
storm
water
and
de­
icing
runoff.

The
final
formula
is:
LC
=
QCbkg
+
QC
mos
+
Q(
Cso(
1­
 ))
+
Q(
C
de­
icingo(
1­
 b))

The
constant
 
represents
the
%
urban
storm
water
reduction
necessary
to
achieve
the
BOD
loading
capacity.
This
reduction
was
calculated
by
iteration.
The
allocation
for
the
airport
is
divided
between
the
Port
of
Portland
(
PDX)
and
the
Oregon
Air
National
Guard
(
ANG).
By
analysis
of
the
de­
icing
use
estimates
provided
to
DEQ
by
the
Port
and
the
Air
National
Guard,
it
was
determined
that
the
Port
contributes
about
89%
of
the
de­
icing
load.
The
Port
therefore
receives
89%
of
the
total
airport
waste
load
allocation
(
WLA).
The
Oregon
Air
National
Guard
receives
11%
of
the
total
airport
allocation.
This
is
represented
mathematically
as:

PDX
=
total
airport
LA
x
0.89
ANG
=
total
airport
LA
x
0.11
From
application
of
SIMPTM
(
Simplified
Particulate
Transport
Model)
the
City
of
Portland
predicted
a
150%
increase
in
the
storm
water
pollutant
loading
over
current
loads
to
the
Columbia
Slough
(
BES,
1989).
SIMPTM
is
a
continuous
storm
water
quality
program
that
can
simulate
the
accumulation
and
washoff
of
total
solids
or
particulates
plus
up
to
six
different
pollutants.
Current
storm
water
loads
are
given
2/
3
of
the
BOD5
allocation
and
future
growth
receives
1/
3
of
the
allocation.
The
storm
water
allocation
includes
storm
water
from
two
sources:
industrial
facilities
that
are
required
to
have
general
industrial
storm
water
permits,
and
urban
runoff
from
areas
in
the
Slough
watershed
that
are
managed
by
the
designated
management
agencies.
To
estimate
the
area
covered
by
the
industrial
permits,
a
review
of
general
storm
water
permits
in
DEQ
was
conducted.
The
area
covered
by
these
permits
was
calculated.
By
assuming
that
100%
of
the
facilities
that
need
industrial
permits
are
covered
in
these
files,
the
area
was
calculated
to
be
997
acres.
Using
an
adaptation
of
the
simple
method
(
EPA
1992),
the
annual
load
of
BOD5
from
industrial
permitted
sites
can
be
calculated:

Area
x
Annual
Rainfall
x
Runoff
Coefficient
x
Pollutant
Concentration
=
Annual
Pollutant
Load
area
=
997
acres
runoff
coefficient
=
0.681
annual
rainfall
=
34.4
inches2
pollutant
concentration
=
68
mg/
L
BOD3
1
Table
3­
13,
Part
2,
City
of
Portland
MS4
permit
application,
industrial
land
use
runoff
coefficient.
2
Table
3­
12,
Part
2,
City
of
Portland
MS4
permit
application,
storm
event
statistics.
3
Table
3­
14,
Part
2,
City
of
Portland
MS4
permit
application,
water
quality
pollutant
concentrations
utilized
for
land
use
pollutant
loading
model,
industrial
land
use.
14
Using
this
equation,
a
value
of
358,
342
lb/
year
of
BOD5
is
obtained
for
permitted
industrial
sites.
To
estimate
the
BOD5
load
from
the
area
managed
by
the
designated
management
agencies
(
DMAs)
(
under
MS4
permits),
the
BOD5
load
from
the
MS4
areas
is
used.
An
estimate
of
the
total
annual
BOD5
load
from
the
area
covered
by
the
Portland
MS4
permit
is
contained
in
Appendix
C
of
the
City
of
Portland
MS4
application.
Using
the
values
for
runoff
coefficients
and
pollutant
concentrations
for
the
subbasins
that
drain
to
the
Slough,
an
annual
BOD5
load
of
655,274
lb/
yr
is
calculated.
The
Gresham
MS4
report
(
Gresham
1996)
estimated
the
annual
BOD5
load
to
the
Slough
as
115,
246,
lb/
yr.
The
total
annual
BOD5
load
from
the
areas
managed
by
the
DMAs
(
under
the
MS4
permits)
is
770,520
lb/
yr.
The
industrial
load
of
358,342
lb/
yr
is
approximately
46.5%
of
the
total
urban
load.
The
industrial
sites
are
allocated
46.5%
of
the
annual
storm
water
BOD5
allocation,
after
the
allocation
for
future
growth
is
set
aside.
This
is
represented
mathematically
as:
Future
growth
WLA
=
total
urban
storm
water
WLA
x
0.333
DMA
WLA
=
total
urban
storm
water
WLA
x
0.6667
x
0.535
Industrial
storm
water
WLA
=
total
urban
storm
water
WLA
x
0.6667
x
0.465
BKG
=
2.5
mg/
L
x
1.98
m3/
sec
x
conversion
factor
=
428
kg/
day
The
allocation
for
PDX
includes
several
co­
permittees.
The
BOD5
allocations
are
summarized
in
Table
2.
Differences
in
the
margin
of
safety
(
MOS)
between
Table
1
and
Table
2
are
due
to
rounding.

Table
2:
BOD5
Waste
Load
Allocations
Implementation
Strategy
Airport
storm
water
permit
PDX
(
and
co­
permittees)
will
be
required
to
conduct
additional
instream
and
source
load
monitoring
and
modeling
to
refine
estimates
of
the
rates
and
loads
used
to
generate
the
LC.
Based
on
these
efforts,
the
LC
and
WLA
may
change.
The
water
quality
monitoring
is
a
joint
effort
with
the
City
of
Portland
and
the
City
of
Gresham.
PDX
will
be
required
to
develop
and
implement
pollution
control
measures
designed
to
achieve
the
WLA.
The
schedule
to
meet
the
WLA
depends
on
the
control
option
PDX
selects.
Option
1
is
treatment
and
discharge
from
PDX
to
the
Columbia
River.
Option
2
is
treatment
and
discharge
to
the
Columbia
Slough.
The
specific
Flow
(
m3/
sec)
BKG
Future
Growth
DMA
Industrial
SW
PDX
ANG
MOS
TMDL
WLA
to
achieve
4.0
mg/
L
DO
criteria,
BOD5,
kg/
day
2.83
428
188
201
175
3342
413
1200
5947
5.66
428
869
931
809
8752
1082
3237
16108
8.50
428
1585
1702
1479
11641
1439
4568
22842
11.33
428
2435
2608
2267
17679
2185
6981
34583
WLA
to
achieve
5.0
mg/
L
DO
criteria,
BOD5,
kg/
day
2.83
428
187
200
174
2801
346
1034
5170
5.66
428
854
914
795
7225
893
2784
13893
8.50
428
1553
1664
1446
9645
1192
3992
19920
11.33
428
2361
2529
2198
14825
1832
6089
30262
WLA
to
achieve
6.5
mg/
L,
DO
criteria,
BOD5,
kg/
day
2.83
428
183
198
172
1978
244
801
4004
5.66
428
822
889
773
4935
610
2114
10571
8.50
428
1500
1607
1396
6652
822
3132
15537
11.33
428
2251
2411
2095
10504
1298
4795
23782
15
timetable
and
requirements
will
be
contained
in
an
individual
NPDES
permit.
The
following
schedule
assumes
that
DEQ
will
issue
the
permit
by
summer
1998.
Under
the
permit
PDX
will
be
required
to:
1.
Implement,
during
the
winters
of
1998/
1999
and
1999/
2000,
a
monitoring
program
for
a
series
of
de­
icing
events.
The
monitoring
will
include
an
approved
Quality
Assurance/
Quality
Control
plan.
The
monitoring
will
provide
synoptic
data
sets
of
loads
and
instream
response
throughout
the
period
of
the
de­
icing
event
and
the
instream
advection
of
the
de­
icing
pulse
to
the
Willamette
River.
Synoptic
monitoring
will
include:
temperature,
BOD5,
dissolved
oxygen,
pH,
stream
flow,
pumping
rates
at
MCDD1,
and
Lower
Columbia
Slough
stage.
De­
icing
load
monitoring
will
include
BOD5,
dissolved
oxygen
and
discharge.
2.
By
October
2000
provide
DEQ
with
a
final
report
describing
model
calibration
efforts.
The
report
will
present
the
basis
for
the
selection
of
rates
and
coefficients
used
in
model
calibration,
a
description
of
how
the
rates
were
derived
and
the
precision
of
calibration.
3.
By
October
2000
identify
the
final
TMDL
BOD
allocations
to
be
achieved
with
implementation
of
controls.
4.
Option
1:
By
winter
2003/
2004
construct
the
treatment
facilities
and
implement
BMPs
necessary
to
meet
the
final
BOD
allocations.
Demonstrate
compliance
with
the
WLA
or:
5.
Option
2:
By
winter
2004/
2005
conduct
pilot
testing
of
treatment
facilities
and
implement
BMPs.
By
winter
2005/
2006
demonstrate
compliance
with
the
WLA.

Designated
Management
Agencies
The
DMAs
will
conduct
monitoring
of
storm
water
BOD5
loads
and
the
instream
response
to
those
loads.
Previous
monitoring
under
the
MS4
permits
has
measured
BOD5
levels
from
urban
runoff
that
do
not
correlate
with
the
few
instream
BOD5
samples
taken
during
storm
events.
The
discrepancy
between
loads
and
instream
concentration
is
likely
due
to
processes
such
as
deposition
and
decay
during
the
transport
to
the
receiving
water.
The
monitoring
data
will
be
used
to
calibrate
a
dynamic
water
quality
model
to
simulate
the
Slough's
response
to
storm
water
and
deicing
fluid.
The
DMA
WLA
will
not
be
included
as
an
effluent
limit.
Achievement
of
the
WLA
will
be
through
implementation
of
BMPs.
Municipal
discharges
will
be
required
to
implement
BMPs
and
demonstrate
that
the
BMPs
achieve
the
WLAs
established.
The
DMAs
will
be
required,
through
MOAs,
to:
1.
Provide
DEQ
with
a
description
of
the
program
designed
to
reduce
BOD5
loads
to
the
Slough.
2.
Implement
a
program
of
BMPs
that
will
reduce
overall
BOD5
load
to
achieve
the
DMA
WLAs.
3.
Implement
coordinated
monitoring
to
define
storm
water
loads
to
the
Slough
and
the
influence
of
storm
water
BOD5
on
receiving
water
quality.
4.
Implement
monitoring
to
demonstrate
compliance
with
BOD5
WLA
targets.
Instream
monitoring
will
include
grab
samples
of
BOD5
and
DO
and
continuous
hydrolab
monitoring.
5.
Implement
water
quality
management
plans
as
developed
as
part
of
the
Lower
Willamette
Subbasin
plan
(
projected
completion
spring
1999).

Table
3:
BOD
Control
Strategy
16
Reach
Control
Strategy
Responsible
DMA
1
1,2,3,4,
City
of
Portland,
PDX
2
1,2,3,4
City
of
Portland,
PDX
3
1,2,3,4
City
of
Portland,
City
of
Gresham
4
1,2
City
of
Fairview,
Multnomah
County
5
1­
5
1­
5
1,2
5
1,2,4
City
of
Fairview,
City
of
Wood
Village,
City
of
Gresham,
Multnomah
County
Oregon
Department
of
Agriculture
Oregon
Department
of
Transportation
Industrial
storm
water
permits
DEQ
anticipates
implementing
storm
water
permits
through
application
of
BMPs.
When
storm
water
permits
are
renewed,
a
basin
specific
general
storm
water
permit
will
be
developed
by
DEQ
to
address
BOD5
loads
as
well
as
other
303(
d)
parameters.
The
permit
will
include
monitoring
and
BMP
requirements
to
reduce
the
BOD5
load
to
the
Slough.
The
WLA
for
industrial
storm
water
will
not
be
incorporated
into
NPDES
industrial
storm
water
permits
as
individual
effluent
limits.

New
discharges
Future
growth
and
development
will
either
have
to
demonstrate
that
adequate
reserve
capacity
exists
in
the
TMDL
or
trade
effluent
with
the
City
of
Portland,
PDX
or
other
DMA.

Eutrophication
(
pH
and
nutrients)

Water
Quality
Criteria
Eutrophication
is
the
increased
primary
productivity
that
occurs
in
an
aquatic
system
as
a
result
of
nutrient
input.
Nutrients
increase
primary
production
and
photosynthesis
rates.
The
pH
of
water
can
be
directly
influenced
by
photosynthesis.
Plant
growth
increases
pH
during
the
day
as
plants
utilize
carbon
dioxide
in
the
water
during
photosynthesis.
At
night,
plants
respire
and
produce
carbon
dioxide
which
decreases
pH.
pH
outside
the
range
in
which
the
species
evolved
may
result
in
both
direct
and
indirect
toxic
effects.
The
water
quality
standard
states
that
"
pH
values
shall
not
fall
outside
the
ranges
identified
in
paragraphs
(
A),
(
B),
and
(
C)
of
this
subsection.
(
A)
Columbia
River:
7.0
­
8.5;
(
B)
All
other
basin
waters
(
except
Cascade
lakes):
6.5
­
8.5;
(
C)
Cascade
lakes
above
3,000
feet
altitude:
pH
values
shall
not
fall
outside
the
range
of
6.0
to
8.5."
(
OAR
340­
41­
445
(
2)
(
d))
Photosynthesis
may
also
cause
diurnal
swings
in
the
dissolved
oxygen
levels.
The
dissolved
oxygen
criteria
are
discussed
in
the
dissolved
oxygen
TMDL.
Elevated
nutrient
levels
also
generate
nuisance
conditions
due
to
algal
growth.
Chlorophyll
a
is
an
indirect
measurement
of
algal
biomass.
Oregon
rules
(
OAR­
41­
150(
1)(
b)
cite
an
action
level
for
average
chlorophyll
a
concentrations
of
15
ug/
L
(
3
month
average
based
on
a
minimum
of
3
samples)
to
control
growth
of
nuisance
phytoplankton.
When
the
action
level
is
exceeded,
DEQ
will
conduct
studies
to
describe
the
water
quality
problem
and
develop
a
proposed
control
strategy.
17
DEQ
has
established
interim
targets
of
0.1
mg/
L
total
phosphorus
(
TP)
and
0.02
mg/
L
ortho­
phosphate
(
O­
PO4).
These
values
are
based
on
EPA
guidelines
(
EPA
Quality
Criteria
for
Water,
EPA,
1986)
and
Best
Professional
Judgment
of
DEQ
staff.
The
CE­
QUAL­
W2
model
has
been
calibrated
to
evaluate
the
influence
of
nutrient
loads
and
hydraulics
on
water
quality.

Monitoring
Continuous
pH
data
on
the
Slough
demonstrate
large
swings
in
pH
on
a
diurnal
basis
in
the
summer
(
CH2MHill,
Part
1,
1995).
Values
above
8.5
have
occurred
in
the
spring
to
fall.
During
the
summer,
reaches
1A
and
2B
frequently
had
pH
levels
above
8.5.
Similar
diurnal
patterns
between
pH
and
DO
suggest
that
eutrophication
is
the
cause
of
the
violations,
as
DO
is
produced
by
photosynthesis.
Total
phosphorus
concentrations
greater
than
the
0.1
mg/
L
guideline
occur
throughout
the
Slough,
throughout
the
year.
(
CH2MHill,
Part
1,
1995)
Sections
of
Reach
2
and
Reach
1
showed
frequent
exceedance
of
the
dissolved
ortho­
phosphate
guideline.
Exceedance
of
the
nitrate
guideline
was
found
throughout
the
Slough
during
all
seasons
(
CH2MHill,
Part
1,
1995).
During
the
summer,
spring
and
fall,
the
Columbia
Slough
also
exceeds
the
action
level
for
chlorophyll
a,
although
the
fall
averages
are
often
skewed
due
to
high
chlorophyll
a
values
in
the
summer
.
Winter
chlorophyll
a
values
are
generally
low
(
CH2MHill,
Part
1,
1995).
The
following
graphs
demonstrate
this
exceedance,
at
sites
in
the
Lower
and
Upper
Slough,
respectively
(
1993­
1997
grab
data).

SJB,
chlorophyll
a
3
month
average
0.000
5.000
10.000
15.000
20.000
25.000
30.000
35.000
40.000
45.000
50.000
55.000
60.000
65.000
70.000
75.000
1/
0
2/
19
4/
9
5/
29
7/
18
9/
6
10/
26
12/
15
day
chlorophyll
a,
ug/
L
Figure
3:
Site
SJB
chlorophyll
a
3
month
average
18
US­
1,
chlorophyll
a
3
month
average
0.000
5.000
10.000
15.000
20.000
25.000
30.000
1/
0
2/
19
4/
9
5/
29
7/
18
9/
6
10/
26
12/
15
day
chlorophyll
a,
ug/
L
Figure
4:
Site
US­
1,
chlorophyll
a
3
month
average
Despite
elevated
average
chlorophyll
a
values,
summer
chlorophyll
a
values
have
decreased
recently
(
since
1992),
although
not
to
the
action
level.
The
following
table
shows
data
for
July
­
September,
when
available.

Table
4:
Summer
Chlorophyll
a
values
Site
Year
SJB
(
RM
2.9)
US­
1
(
RM
8.7)
1992
53.6
35.9
1993
NA
NA
1994
NA
NA
1995
7.68
3.13
1996
30.43
18.75
1997
32.0
19.08
Improvements
in
pH
variation
have
been
observed
in
the
summer
of
1996
in
the
Slough.
At
St.
John's
Landfill
Bridge
(
site
SJB,
main
channel,
Lower
Slough,
Reach
1)
there
has
been
significant
improvement
in
pH
since
1992,
as
seen
in
the
following
graphs
generated
from
continuous
Hydrolab
data:
19
pH
fre
qu
e
ncy
,
S
JB
,
1
9
92
6
.5
7
7
.5
8
8
.5
9
9
.5
0%
10%
20%
3
0
%
40%
50%
60%
70%
80%
90%
10
0%

freq
u
en
c
y
p
H
Figure
5:
pH
July
 
September
92
pH
frequency,
SJB,
1996
6.5
7
7.5
8
8.5
9
9.5
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%

frequency
pH
Figure
6:
pH
July
 
September
1996
At
site
MCDD1,
summer
1996
pH
levels
were
within
the
criteria,
for
data
recorded
when
the
hydrolab
was
properly
calibrated.
Additional
pH
data
is
contained
in
Appendix
C,
although
data
for
summer
1993
and
1994
is
limited.
Dissolved
orthophosphate
values
in
both
the
Upper
and
Lower
Slough
were
approximately
0.02
mg/
L,
or
at
the
guideline
level
(
summer
1996
grab
data).
Examination
of
data
from
summer
1992
at
sites
SJB
and
MCDD1
did
not
indicate
any
violations
of
the
4
mg/
L
instantaneous
minimum
dissolved
oxygen
criterion
(
see
Appendix
C
for
data).
Samples
taken
from
a
location
near
the
outlet
of
Fairview
Lake
(
Reach
3),
showed
frequent
and
long
term
oxygen
depressions
in
the
summer.
The
data
presented
below
is
from
sampling
site
US­
8,
located
at
Fairview
Lake
outlet
in
the
main
channel
in
Reach
3.
However,
flow
from
Fairview
Lake
is
limited
by
summer
operations
designed
to
keep
the
water
level
high
in
the
Lake.
Resulting
stagnant
water
combined
with
a
relatively
high
sediment
oxygen
demand
(
SOD)
(
1.9
mg/
m2/
day
­
O,
measured
in
the
forebay
to
MCDD1,
(
Wells,
personal
communication,
1997)
may
be
causing
low
DO
readings
in
the
sampling
location
on
Reach
3.
Additionally,
there
are
no
known
sources
of
BOD
discharge
in
this
area.
These
DO
concentrations
may
not
be
representative
of
the
entire
reach
(
CH2MHill,
Part
1,
1995).
20
Figure
7:
Reach
3
summer
DO
The
continuous
monitoring
equipment
at
Site
US­
8
is
now
placed
within
Fairview
Lake.
Currently,
the
closest
continuous
dissolved
oxygen
data
is
available
from
Site
158,
approximately
2
miles
west
of
the
outlet
of
Fairview
Lake.
Data
from
summer
1996
indicates
improvement
in
water
quality,
with
dissolved
oxygen
levels
above
the
4.0
mg/
L
instantaneous
minimum.
Figures
8
and
9
summarize
this
information.

Site
158,
DO
June
­
July
1996
0
2
4
6
8
10
12
14
16
18
6/
9/
96
0:
00
6/
14/
96
0:
00
6/
19/
96
0:
00
6/
24/
96
0:
00
6/
29/
96
0:
00
7/
4/
96
0:
00
7/
9/
96
0:
00
7/
14/
96
0:
00
7/
19/
96
0:
00
7/
24/
96
0:
00
7/
29/
96
0:
00
Date
DO,
mg/
L
Figure
8:
Site
158
June
­
July
1996
Site
US­
8,
DO
summer
92
0
1
2
3
4
5
6
7
8
9
10
7/
23/
92
0:
00
7/
28/
92
0:
00
8/
2/
92
0:
00
8/
7/
92
0:
00
8/
12/
92
0:
00
8/
17/
92
0:
00
8/
22/
92
0:
00
8/
27/
92
0:
00
9/
1/
92
0:
00
Date
DO,
mg/
L
21
Site
158,
August
­
Sept.
96
DO
0
2
4
6
8
10
12
14
16
18
20
8/
11/
96
0:
00
8/
21/
96
0:
00
8/
31/
96
0:
00
9/
10/
96
0:
00
9/
20/
96
0:
00
9/
30/
96
0:
00
Date
DO,
mg/
L
Figure
9:
Site
158
August
­
September
1996
Water
level
management
activities
have
led
to
this
water
quality
improvement.
However,
as
discussed
previously,
the
chlorophyll
a
action
level
is
still
exceeded,
throughout
the
year.
The
action
level
requires
initiating
studies
to
determine
the
cause
of
eutrophication.
Achievement
of
the
water
quality
criteria
influenced
by
algal
growth
(
DO
and
pH)
provides
the
TMDL
requirements.
The
implementation
section
describes
the
water
level
management
activities
to
date,
as
well
as
additional
controls
that
will
be
necessary
to
control
algal
growth.

Modeling
Using
the
CE­
QUAL­
W2
model,
Wells
and
Berger
(
1994)
demonstrated
that
a
major
cause
of
algal
growth
in
the
late
summer
(
August
­
September)
in
the
Upper
Slough
was
excessive
dissolved
ortho­
phosphate
from
groundwater
and
in
Lower
Slough
was
mainly
from
discharges
of
nutrients
and
algal
rich
water
from
the
Upper
Slough.
Point
source
loads
are
minor.
Most
of
the
point
source
summer
PO4
loads
are
a
byproduct
of
the
origin
of
the
water
source,
because
the
discharges
are
of
cooling
water.
Various
management
strategies
have
been
simulated
to
evaluate
their
effect
on
water
quality
in
the
Slough.
Wells
(
1995,
EWR­
2­
95)
simulated
a
90%
reduction
in
dissolved
ortho­
phosphate
in
groundwater
and
results
demonstrated
that
this
reduction
would
result
in
the
lowest
chlorophyll
a
concentration
of
all
the
simulations.
Modeling
also
indicated
(
Wells
and
Berger,
1993)
that
reducing
the
water
level
from
8
ft
to
5
ft
MSL
(
outflow
of
70
CFS)
would
reduce
the
overall
detention
time
from
about
4
days
to
less
than
one
day.
Reducing
the
detention
time
decreased
the
time
available
for
algal
growth.
The
detention
time
determines
the
loading
capacity
of
the
Slough
for
nutrients.
As
a
result
of
the
modeling
water
level
management
was
initiated
in
the
Slough.
Rooted
aquatic
vegetation
is
growing
in
the
Upper
Slough.
A
significant
loss
of
the
nutrients
supplied
by
groundwater
has
been
observed.
The
loss
appears
22
associated
with
greater
settling
of
solids
and
uptake
by
epiphytes
associated
with
the
macrophytes.
The
effect
of
this
vegetation
on
Slough
water
quality
was
modeled,
as
was
the
effect
of
increased
total
phosphate
loads.
To
account
for
the
affect
of
macrophyte
growth
on
Upper
Slough
water
quality
the
base
case
simulations
used
the
average
1996
data
for
inflow
concentrations
from
the
Upper
Slough.
The
effect
of
groundwater
and
minor
storm
water
inputs
were
simulated.
Total
phosphate
loads
were
increased
by
increasing
the
ortho
phosphate
load.
Additional
simulations
were
conducted
in
which
total
phosphate
was
increased
by
increasing
both
the
ortho­
phosphorus
and
algae.
The
algae
flowing
from
the
Upper
to
the
Lower
Slough
served
as
a
seed
for
algae
in
the
Lower
Slough,
so
this
was
a
conservative
modeling
approach.
The
total
phosphate
loads
and
the
resulting
pH
are
graphed
below
(
memo
from
Chris
Berger,
Portland
State
University,
to
DEQ,
draft,
May
15,
1998).
Simulations
demonstrate
that
at
current
conditions
(
the
first
point
on
each
graph)
the
maximum
pH
is
about
8.14.
The
minimum
dissolved
oyxgen
was
7.33
mg/
L
(
memo
from
Chris
Berger,
Portland
State
University,
to
DEQ,
draft,
May
15,
1998).
The
effect
of
summer
storm
water
loads
was
also
modeled
and
compared
to
the
base
run,
which
simulates
existing
conditions.
Results
indicate
that
the
effect
of
summer
storm
water
loads
is
minimal,
with
the
predicted
DO
and
pH
meeting
the
criteria.

Algal
Growth
in
Columbia
Slough
in
relation
to
changes
in
PO4
load
8.1
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
15.00
20.00
25.00
30.00
35.00
40.00
Load
(
kg/
d)
Maximum
pH
Increase
only
Ortho
Increase
Ortho
and
Algal
seed
Figure
10:
Total
Phosphate
Loads
and
pH
Loading
Capacity
and
Margin
of
Safety
Defined
A
loading
capacity
is
defined
only
for
total
phosphate
because
the
Slough
is
so
nitrogen
rich
that
PO4
is
the
limiting
nutrient.
A
review
of
summer
1992
data
at
North
Portland
Bridge
in
the
Lower
Slough
indicated
that
NO3­
N
was
present
at
levels
10
times
greater
than
total
phosphate
levels.
As
seen
in
Figure
10,
the
current
load
of
total
phosphate
is
23.25
kg/
day.
With
a
total
phosphate
load
of
27.1
kg/
day
(
for
simulations
with
both
increasing
ortho
phosphate
and
algae
seed)
the
pH
will
raise
to
8.5.
To
set
allocations
and
a
margin
of
safety,
the
instream
concentration
which
met
this
load
was
calculated
by
dividing
the
load
by
the
estimated
total
flow
simulated.
The
maximum
instream
concentration
is
0.1549
mg/
L
total
phosphate
(
to
a
pH
of
8.5).
To
set
allocations
at
flows
of
1.98
23
m3/
sec,
2.83
m3/
sec
and
5.66
m3/
sec,
the
instream
concentrations
were
multiplied
by
flow
to
calculate
the
allowable
daily
load.
This
calculation
is
as
follows:

1.98
m3/
sec
X
0.1549
mg/
L
X
1000L/
m3
X
1
kg/
106
mg
X
60
sec/
min
X
60
min/
hr
X
24
hr/
day
=
26.5
kg/
day
=
loading
capacity
The
loading
capacity
was
then
divided
between
groundwater,
storm
water,
one
point
source
discharge,
the
margin
of
safety
(
MOS)
and
the
loss
due
to
macrophytes.
The
distribution
between
storm
water
and
groundwater
was
calculated
using
the
ratio
of
storm
water
to
groundwater
loads
used
in
the
modeling.
The
ratio
is
0.27
storm
water
to
0.73
groundwater.
The
loss
to
macrophytes
was
calculated
as
the
difference
between
concentrations
measured
upstream
of
MCDD1
and
the
concentrations
at
MCDD1
(
memo
from
Chris
Berger,
Portland
State
University,
to
DEQ,
draft,
May
15,
1998).
The
margin
of
safety
is
set
by
using
the
conservative
modeling
results
in
which
total
phosphorus
is
increased
by
increasing
both
ortho­
phosphate
and
algae
seed
concentrations.
Additionally,
the
remaining
loading
capacity,
after
allocation
to
the
existing
loads,
is
set
aside
as
the
numerical
margin
of
safety.

Allocations
Allocations
are
set
only
for
the
spring
through
fall
(
April­
October),
when
the
Slough
is
water
quality
limited
due
to
eutrophication.
No
allocations
are
set
for
the
winter
months.
Uncontrolled
sewage
receives
an
allocation
of
zero.
Additionally,
by
2002,
combined
sewer
overflows
(
CSOs)
will
receive
a
zero
allocation
except
for
a
1
in
10
year
summer
event.
The
1
in
10
year
storm
event
discharge
is
allocated
at
the
current
CSO
load.
Modeling
shows
that
new
waste
water
point
source
loads
during
periods
of
algal
growth
would
increase
productivity
and
standards
violations,
so
a
WLA
of
zero
for
new
point
source
loads
of
PO4
is
established.
One
point
source
discharge
may
discharge
phosphate
and
receives
an
allocation
that
results
in
no
measurable
increase
above
existing
instream
total
phosphate
levels.
The
calculation
for
this
waste
load
allocation
is
discussed
below.

Existing
Point
Source
Discharge
Oregon
Fresh
Farms
(
OFF)
operates
a
carrot
packaging
plant
and
discharges
to
the
Whitaker
Slough.
The
discharge
occurs
from
July
­
December,
and
may
extend
into
February.
This
discharge
receives
an
allocation
for
total
­
phosphate
that
results
in
no
measurable
increase
above
current
levels.
Using
data
from
BES,
the
median
(
approximate)
value
for
total
phosphate
in
Whitaker
Slough
is
0.14
mg/
L
(
65
samples,
March
1­
June
30,
1995­
1997).
Upstream
flow
was
calculated
as
the
average
of
measured
daily
flow
from
July
­
February
(
161
samples.
BES
database).
The
flow
from
Oregon
Fresh
Farms
was
calculated
as
the
average
of
the
average
daily
flows
recorded
on
the
Discharge
Monitoring
Reports
(
DMRs)
for
the
facility
(
DMRs
dated
September
­
November
1997.)
The
allocation
is
calculated
as
follows:
(
Cups)(
Qups)
+
(
Ceff)(
Qeff)
=
(
Cmix)(
Qmix)
Where:
Cups
=
upstream
concentration
=
0.14
mg/
L
Qups
=
upstream
flow
=
27.2
CFS
Ceff
=
effluent
concentration
=
X
Qeff
=
effluent
flow
=
1.5
CFS
24
Cmix
=
concentration
of
mixed
stream
=
Cups
+
CDL
=
0.16
mg/
L
CDL
=
0.02
mg/
L
(
DEQ
detection
limit
for
total
phosphate
analysis)
Qmix
=
flow
of
mixed
stream
=
28.7
CFS
Solving
for
Ceff,
yields
a
total
phosphate
concentration
of
0.52
mg/
L.
Using
the
average
daily
flow
from
the
DMRs,
the
load
allocation
is:

0.52
mg/
L
x
1.5
ft3/
sec
x
1
m3/
35.3
ft3
x
1
kg/
106
mg
x
60
sec/
min
x
60
min/
hr
x
24
hr/
day
x
1000L/
m3
=
1.91
kg/
day
The
loading
capacity
is
allocated
as
follows:
LC
=
groundwater
+
storm
water
+
OFF
+
MOS
+
Loss
+
CSO
+
untreated
sewage
The
results
are
summarized
in
Table
5.

Table
5:
Total
Phosphate
Loading
Capacity
and
Allocations
Allocations
(
kg/
day)

Flow
(
m3/
sec)
Groundwater
Storm
water
OFF
Loss
MOS
CSO
Sewage
LC
1.98
20.9
7.7
1.9
­
5.9
1.9
0
0
26.5
2.83
29.9
11.1
1.9
­
8.5
3.5
0
0
37.9
5.66
59.8
22.1
1.9
­
16.9
8.9
0
0
75.8
Implementation
Strategy
Groundwater
Controls
Algal
growth
is
controlled
by
several
factors
including
solar
radiation,
stream
flow
and
transport,
nutrient
cycling
and
nutrient
loads.
In
the
Columbia
Slough
the
dominant
factor
influencing
summer
algal
growth
that
can
be
managed
and
controlled
is
stream
flow
and
transport,
and
to
a
lesser
extent
nutrient
cycling
and
solar
radiation.
The
previously
described
modeling
demonstrates
that
the
dominant
source
of
nutrients
is
from
groundwater.
Groundwater
controls
have
already
been
established
for
the
Slough,
but
the
effectiveness
at
PO4
reduction
is
uncertain.
In
1984,
a
study
concluded
that
more
than
14
million
gallons
a
day
of
waste
from
unsewered
areas
of
Mid
Multnomah
County
were
discharged
directly
to
the
groundwater,
which
flowed
toward
the
Slough
(
The
East
County
Sanitary
Sewer
Consortium,
June
1984).
Sanitary
sewers
will
be
constructed
in
this
area
and
all
property
owners
connected
to
it
by
the
year
2005
(
East
Multnomah
County,
1995)
(
Findings
and
Order,
Environmental
Quality
Commission,
1/
30/
86).
With
the
removal
of
these
cesspools,
a
significant
source
of
nitrate
to
the
Slough
is
expected
to
be
removed,
but
it
will
take
approximately
30
years
for
a
reduction
of
40
percent
of
nitrogen
in
groundwater
(
CH2MHill,
Part
2,
1995).
In
addition,
groundwater
may
continue
to
have
high
phosphorus
concentrations
(
0.074
mg/
L
PO4­
P))
4;
other
local
4
Average
of
5
samples
measured
at
NE112
from
7­
9/
96.
NE112
is
believed
to
be
close
to
pure
groundwater
(
Wells
August
1997)
25
aquifers
that
are
unaffected
by
cesspools
have
high
phosphorus
content
(
CH2MHill,
Part
2,
1995).
The
influence
of
sewering
East
Multnomah
County
on
groundwater
PO4
concentration
is
not
known.

Water
level
management
The
management
strategy
for
eutrophication
focuses
on
water
level
management
in
the
Slough.
During
the
summer
of
1996,
water
level
management
increased
the
flows
through
the
Middle
Slough
(
Reach
2)
by
decreasing
water
levels
and
increasing
the
groundwater
inflow.
The
water
level
in
the
Middle
Slough
(
Reach
2)
was
dropped
to
6
feet
MSL,
down
from
8
feet.
The
mid
dike
levee
was
closed.
Gravity
flow
was
also
used
between
the
Middle
(
Reach
2)
and
Lower
Slough
(
Reach
1)
to
lower
the
water
level.
There
was
a
visible
reduction
of
algae
in
many
parts
of
the
Middle
Slough,
but
there
was
an
increase
in
rooted
aquatic
vegetation.
This
increase
in
macrophytes
is
likely
due
to
shallower
depths
and
increased
water
clarity
which
allow
sunlight
to
penetrate
to
the
Slough
bottom
and
rooted
vegetation
to
grow.
The
establishment
of
macrophytes
has
resulted
in
reduced
levels
of
dissolved
ortho­
phosphate,
suspended
solids
and
turbidity.
The
decrease
of
dissolved
ortho­
phosphate
may
be
due
to
biological
uptake
by
the
macrophytes
or
algal
epiphytes.
Water
level
management
demonstrated
significant
reduction
of
algae.
The
City
of
Portland
will
be
required
to
continue
instream
monitoring
to
evaluate
the
effectiveness
of
water
level
management.
The
increased
macrophyte
growth
results
in
greater
flood
control
management
problems
for
the
Multnomah
County
Drainage
District
(
MCDD).
The
DEQ
will
work
with
MCDD
to
develop
a
management
plan
and
to
document
the
influence
of
the
macrophyte
growth
on
beneficial
uses
of
the
Slough.

Storm
water
Best
Management
Practices
Specific
responsibilities
for
monitoring
water
quality
and
implementing
BMPs
to
control
storm
water
phosphate
loading
will
be
contained
in
MOAs
DEQ
will
negotiate
with
each
DMA.
Instream
water
quality
will
continue
to
be
monitored
to
help
assess
trends
in
water
quality
and
determine
if
BMPs
are
improving
water
quality.
General
requirements
that
will
be
contained
within
the
MOAs
are
summarized
below:

Designated
management
agencies
1.
Identify
at
least
3
representative
sites
for
the
Lower
(
Reach
1),
Middle
(
Reach
2)
and
Upper
(
Reach
3)
Slough
for
long
term
monitoring
of
water
quality
in
the
Slough
to
determine
the
effectiveness
of
the
implementation
strategy.
2.
Identify
representative
site
in
Fairview
Lake
(
Reach
4)
and
Fairview
Creek
(
Reach
5)
to
characterize
water
quality
in
these
water
bodies
and
determine
effectiveness
of
control
strategies.
Water
quality
parameters
will
include
DO,
pH,
temperature,
chlorophyll
a,
dissolved
ortho
phosphate,
total
phosphate
and
bacteria.
3.
Maintain
the
hydrolab
pH
measurements
as
well
as
the
grab
samples
of
pH,
dissolved
ortho­
phosphate,
chlorophyll
a
,
DO
and
temperature.
4.
Identify
BMPs
in
MS4
permits
which
may
reduce
contributions
of
phosphate
via
storm
water.
5.
Include
PO4
in
assessment
of
BMP
effectiveness
by
measurement
of
influent
and
effluent
dissolved
ortho
phosphate
concentrations
and
total
phosphate
concentrations.
26
6.
Remove
CSOs
except
for
a
1
in
10
year
summer
event
and
one
in
five
year
winter
event.
7.
Implement
water
quality
management
plans
as
developed
as
part
of
the
Lower
Willamette
Subbasin
plan
(
projected
completion
spring
1999).

These
requirements
are
listed
by
responsible
DMAs,
for
each
reach,
below:

Table
6:
Nutrient
Control
Summary
Reach
Control
Strategy
Responsible
DMA
1
1,3,4,5,6
City
of
Portland
1
1,3,4,5
PDX
2
1,3,4,5
City
of
Portland,
PDX
3
1,3,4,5
City
of
Portland,
City
of
Gresham
4
2,4,5
City
of
Fairview,
Multnomah
County
5
1­
5
1­
5
2,4,5
7
1,3,4,5
City
of
Fairview,
City
of
Gresham,
City
of
Wood
Village,
Multnomah
County
Oregon
Department
of
Agriculture
Oregon
Department
of
Transportation
BACTERIA
Water
Quality
Criteria
The
purpose
of
the
bacterial
water
quality
standard
is
to
protect
the
most
sensitive
designated
beneficial
use,
which
is
primary
water
contact
recreation,
such
as
swimming.
Recreational
exposure
to
water
polluted
with
human
pathogens
can
cause
skin
and
respiratory
ailments,
gastroenteritis,
and
other
illnesses.
Certain
species
of
bacteria
are
used
as
indicators
for
the
presence
of
other
microbes
because
of
their
common
fecal
origin
and
the
relative
ease
by
which
they
can
be
counted.
The
State
of
Oregon
recently
adopted
a
new
bacteria
criteria
which
changes
indicator
species
from
fecal
coliform
to
E.
coli
and
contains
narrative
provisions
that
describe
the
requirements
for
a
water
quality
plan
for
water
quality
limited
waterbodies.
Most
of
the
available
bacteria
data
for
the
Columbia
Slough
is
fecal
coliform,
so
the
water
quality
limited
designation
for
the
Slough
was
determined
by
compliance
with
the
historical
standard.
Under
the
historical
criteria,
samples
may
not
exceed
200/
100mL
log
mean
based
on
a
minimum
of
5
samples
in
a
30­
day
period;
no
more
than
10%
of
samples
in
a
30
day
period
may
be
>
400/
100mL.
Because
of
the
difficulty
in
sampling
frequently
enough
to
determine
compliance
with
the
criteria,
DEQ
has
allowed
flexibility
in
interpretation
of
available
data.
A
waterbody
is
considered
water
quality
limited
for
bacteria,
and
placed
on
the
303(
d)
list,
when
the
geometric
mean
of
fecal
coliform
bacteria
exceeds
200
per
100
milliliters
or
more
than
10%
of
the
samples
and
a
minimum
of
at
least
two
samples
exceed
400
per
100
milliliters
for
the
season
of
interest.
(
DEQ,
1996)
Under
the
new
criteria,
samples
may
not
exceed
a
30­
day
log
mean
of
126
E.
coli
organisms
per
100
mL,
based
on
a
minimum
of
5
samples.
No
single
sample
may
exceed
406
E.
coli
organisms
per
100
mL.
The
criteria
prohibits
the
discharge
of
raw
sewage
into
waters
of
the
State
(
OAR
340­
41­
445
(
2)
(
e)).
The
sewage
must
be
treated
in
a
manner
approved
by
DEQ.
Current
regulations
describe
the
implementation
27
requirements
for
water
quality
limited
(
WQL)
waterbodies.
Bacteria
management
plans
must
be
developed
for
waterbodies
that
are
water
quality­
limited
for
bacteria.
These
management
plans
will
identify
the
specific
technologies
and
BMPs
to
be
implemented
by
point
and
nonpoint
sources
to
limit
bacterial
contamination.
For
point
sources,
the
bacteria
management
plan
will
be
part
of
their
NPDES
permit.
For
nonpoint
sources,
the
bacteria
management
plan
will
be
developed
by
the
DMAs
which
will
identify
the
appropriate
BMPs.
Additionally,
the
criteria
state
that
domestic
waste
collection
and
treatment
facilities
are
prohibited
from
discharging
raw
sewage
during
November
1
through
May
21
except
during
a
storm
event
greater
than
the
one­
in­
five
year,
24
hour
duration
storm.
Facilities
are
prohibited
from
discharging
raw
sewage
during
the
period
of
May
22
through
October
31,
except
during
a
storm
event
greater
than
the
one­
in­
ten
year,
24
hour
duration
storm.

Monitoring
Due
to
the
cost
of
collecting
5
samples
in
a
30
day
period,
insufficient
fecal
coliform
data
are
available
to
evaluate
historical
compliance
with
the
standard.
Because
of
the
scarcity
of
data
and
the
change
in
the
bacteria
standard
to
E.
coli,
fecal
coliform
data
are
compared
to
the
303(
d)
listing
criteria.
Enterococci
data
are
used
only
to
provide
evidence
of
fecal
contamination.
Fecal
contamination
appears
throughout
the
Slough,
although
the
magnitude
of
the
contamination
varies
widely.
Appendix
C
contains
additional
fecal
coliform
data.
The
highest
bacteria
concentrations
have
been
found
in
the
Lower
Slough
in
winter
months,
indicative
of
CSO
events.
In
Reaches
1A
and
1B,
winter
samples
often
had
fecal
coliform
levels
greater
than
1000/
100
mL.
In
Reach
1B,
about
74%
of
the
winter
samples
are
greater
than
400/
100
mL.
For
the
spring,
there
are
few
fecal
coliform
or
enterococci
samples,
but
the
available
data
indicate
fecal
contamination.
In
the
summer,
Reaches
1B
and
1C
had
fecal
coliform
values
greater
than
1000/
100
mL.
About
31%
of
the
summer
samples
in
Reach
1B
had
fecal
coliform
concentrations
greater
than
400/
100
mL.
Enterococci
concentrations
for
these
reaches
also
were
high
(>
200/
100
mL),
indicating
that
the
bacteria
were
of
fecal
origin.
In
the
fall,
Reaches
1B
and
1C
show
elevated
fecal
coliform
values
(>
1000/
100
mL).
Enterococci
samples
confirm
the
evidence
of
fecal
contamination
in
these
reaches
in
the
fall
(
CH2MHill,
Part
1,
1995).
Data
for
the
Middle
Slough
(
Reach
2)
also
indicates
fecal
contamination.
About
14%
of
the
winter
samples
for
Reach
2A
had
values
greater
than
400/
100mL.
In
the
summer
Reach
2A
had
fecal
coliform
values
greater
than
1000/
100
mL.
In
the
fall,
Reaches
2A
and
2C
show
elevated
fecal
coliform
values(>
1000/
100
mL).
Enterococci
samples
confirm
the
evidence
of
fecal
contamination
in
these
reaches
in
the
fall
(
CH2MHill,
Part
1,
1995).
Data
from
1995
­
1998
does
not
indicate
a
violation
of
the
fecal
coliform
criteria
in
Reach
3.
The
geometric
mean
of
the
samples
from
east
of
the
mid­
dike
levee
to
the
outlet
of
Fairview
Lake
is
73
CFU/
100
mL.
At
the
90th
percentile,
the
fecal
coliform
concentration
is
<
300
CFU/
100
mL.

Data
Analysis
Part
II
of
the
Water
Body
Assessment
(
CH2MHill,
1995)
describes
the
modeling
efforts
that
were
undertaken
in
order
to
quantify
pollutant
loads
to
the
Columbia
Slough.
The
28
EPA
storm
water
model
SWMM
(
EPA
1992)
was
used
to
develop
estimates
of
flows
and
pollutant
loadings
from
the
various
land
use
categories
and
subbasins
draining
to
the
Slough.
The
data
collected
as
part
of
the
Portland
storm
water
NPDES
permit
were
used
to
calibrate
flow
contributions
and
derive
land
use
based
event
mean
pollutant
concentrations
(
EMCs)
for
specific
pollutants.
Pollutant
loads
were
based
on
land
use.
The
basin's
response
to
storm
events
was
calibrated
by
comparing
monitored
flow
rates
for
numerous
storm
events
recorded
between
December
1991
and
December
1994.
Table
7
summarizes
the
results
by
reach
for
fecal
coliform
bacteria.
Model
predictions
using
E.
coli
are
not
available,
but
overall
trends
in
loads
are
expected
to
be
the
same.

Table
7:
Estimated
Percentage
Breakdown
of
Fecal
Coliform
Loads
Source
Lower
Slough
Middle
Slough
Upper
Slough
summer
winter
summer
winter
summer
winter
storm
water
1.1
1.3
4.8
21.4
90.9
90.9
CSO
67.0
84.3
NA
NA
NA
NA
unknown/
uncontrolled
9.0
8.8
94.9
76.6
0.0
0.0
upstream
1.5
2.9
0.3
2.0
9.1
9.1
Smith
&
Bybee
Lakes
0.3
0.1
NA
NA
NA
NA
Willamette
River
21.1
2.6
NA
NA
NA
NA
NA
=
not
applicable
These
results
indicate
that
Combined
Sewer
Overflows
(
CSOs)
are
the
dominant
source
of
bacteria
in
the
Lower
Slough.
The
Upper
and
Middle
Slough
contribute
only
<
3%
of
bacteria
loads
to
the
Lower
Slough.
The
Middle
Slough
is
mainly
affected
by
illicit
sources
such
as
failing
septic
systems
and
illicit
connections.
In
the
Upper
Slough,
the
most
significant
source
appears
to
be
storm
water.
There
are
13
CSO
outfalls
located
in
the
Lower
Slough
itself,
and
because
the
Lower
Slough
is
tidally
influenced,
it
is
additionally
impacted
by
the
presence
of
CSOs
in
the
Willamette
River.
CE­
QUAL­
W2
modeling
indicates
that
removal
of
the
CSOs
will
bring
the
Lower
Slough
into
compliance
with
the
bacteria
standard.
(
Wells,
EWR­
2­
95).
Approximately
85­
90%
of
CSOs
in
the
Willamette
will
be
removed
when
the
CSO
program
for
the
Willamette
River
is
complete.
The
Middle
Slough
does
not
contain
any
CSOs,
however
there
are
indications
that
illicit
discharges
are
taking
place.
These
indications
are:
 
Measured
instream
concentrations
are
substantially
higher
than
those
predicted
via
modeling.
This
indicates
the
presence
of
previously
unsuspected
source(
s)
not
incorporated
into
the
model
(
CH2MHill,
WBA,
Part
II).
 
The
staff
of
the
Multnomah
County
Drainage
District
has
observed
conditions
in
the
Middle
Slough
that
they
believe
indicate
houses
in
the
area
discharge
directly
to
the
Slough
(
Hayford,
personal
communication).
 
A
search
of
the
City
of
Portland's
records
pertaining
to
the
sewer
system
in
the
vicinity
of
the
Middle
Slough,
indicates
that
there
are
houses
for
which
no
record
of
connection
exists.

Table
8
compares
existing
instream
summertime
conditions
to
model
predictions
for
the
Middle
Slough,
which
assumes
no
illicit
discharges,
to
the
fecal
criteria.
Comparison
is
of
the
predicted
instream
fecal
coliform
values
to
the
two
components
of
29
the
criteria;
200/
100
mL
as
the
median
value
for
compliance
and
400/
100
mL
as
the
instantaneous
maximum.

Table
8:
Comparison
of
Fecal
Coliform
Values
in
the
Middle
Slough
Scenario
%
of
values
that
exceed
200/
100
mL
%
of
values
that
exceed
400/
100
mL.
1.
Existing
(
with
illicit
discharge)
30.6
15.9
2.
Proposed
(
with
illicit
discharge
removed)
<
1
<
1
The
existing
case
is
based
on
sampling
results.
For
the
proposed
case,
they
are
based
on
modeled
results
(
CH2MHill,
1995).
Unknown
sources
appear
to
be
the
major
sources
of
bacteria.
Modeling
results
indicate
that
the
elimination
of
storm
water
from
Reach
2
would
not
have
a
significant
effect
on
bacteria.
In
contrast,
the
model
predicted
that
elimination
of
fecal
coliform
in
storm
water
in
Reach
3
(
Upper
Slough)
would
reduce
the
frequency
of
exceedances
of
the
fecal
coliform
standard
from
16
percent
to
zero
percent.
Storm
water
was
the
only
modeled
source
containing
coliform
in
Reach
3.
Because
existing
data
on
the
Upper
Slough
is
too
limited
to
state
whether
or
not
there
are
problems
with
respect
to
bacteria,
additional
monitoring
will
be
needed
to
confirm
the
modeling
conclusions.
To
implement
the
new
bacteria
standard,
the
TMDL
requires
development
of
bacteria
management
plans.
The
management
plans
will
include
detection
and
removal
of
illicit
discharges,
control
of
bacteria
from
storm
water
and
monitoring
to
demonstrate
compliance
with
the
criteria.
The
TMDL
also
requires
the
removal
of
sources
of
raw
human
waste.

Margin
of
Safety
The
Upper
Slough
is
not
impacted
by
CSOs,
so
the
margin
of
safety
is
calculated
by
examination
of
modeling
and
monitoring
results
for
the
Upper
Slough.
Modeling
of
instream
response
to
bacteria
loads
into
the
Upper
Slough
(
Wells,
EWR­
2­
95)
has
a
precision
of
±
15
fecal
coliforms.
This
measurement
of
precision
is
used
to
define
the
margin
of
safety.
Because
the
model
results
were
for
fecal
coliform
and
the
criteria
is
now
E.
Coli,
data
from
the
Upper
Slough
(
1995
­
1998)
was
reviewed
to
determine
if
their
is
a
relationship
between
measured
E.
Coli
data
and
measured
fecal
coliform
data.
The
data
sets
are
significantly
related
(
probability
<
.01)
and
the
ratio
of
E.
Coli/
fecal
coliforms
is
0.82.
The
ratio
is
multiplied
by
the
precision
to
obtain
the
MOS:
15
fecal
coliforms
x
(
0.82
E.
Coli/
fecal
coliforms)
=
12.3
E
Coli.

Loading
Capacity
Defined
The
bacteria
criteria
contains
two
components;
<
126
log
mean
based
on
a
minimum
of
5
samples
in
a
30
day
period
and
no
single
sample
>
406.
To
determine
the
loading
capacity
the
E.
coli
log
mean
criterion
is
multiplied
by
the
range
of
flow
in
the
Slough.

Table
9:
E.
Coli
Bacteria
Loading
Capacity
30
Flow
(
m3/
s)
Criteria
(
MPN/
100
mL)
5
LC
(
MPN/
day)
MOS
(
MPN/#
100
mL)
MOS
(
MPN/
day)
LC­
MOS
(
MPN/
day)

Base
Flow
1.98
126
2.16
x
1011
12.3
2.10
x
1010
1.95
x
1011
Storm
Flow
2.83
126
3.08
x
1011
12.3
3.01
x
1010
2.77
x
1011
5.66
126
6.16
x
1011
12.3
6.02
x
1010
5.55
x
1011
8.50
126
9.25
x
1011
12.3
9.03
x
1010
8.34
x
1011
Allocations
The
untreated
CSO
discharges
to
Columbia
Slough
will
be
eliminated
except
during
storms
greater
than
or
equal
to
a
storm
with
a
five
year
return
frequency
from
November
1
through
April
30
and
except
during
storms
greater
than
or
equal
to
a
storm
with
a
ten
year
return
frequency
from
May
1
through
October
31.
(
Amended
Stipulation
and
Final
Order
No.
WQ­
NWR­
91­
75).
CSOs
therefore
receive
a
wasteload
allocation
of
zero,
except
for
the
storms
as
stated
in
the
Order.
Raw
sewage
also
receives
an
allocation
of
zero.
As
seen
in
Table
7,
upstream
sources
contribute
about
10%
of
the
bacteria
to
the
Slough
and
storm
water
90%.
The
loading
capacity
(
minus
the
margin
of
safety)
is
allocated
to
these
two
sources
proportional
to
their
contribution.
Table
10
summarizes
the
allocations.
The
allocations
are
annual.

Table
10:
E.
Coli
Allocations
Allocations
(
MPN/
day)

Flow
Source
1.98
m3/
sec
2.83
m3/
sec
5.66
m3/
sec
8.50
m3/
sec
CSO
0
0
0
0
raw
sewage
0
0
0
0
storm
water
1.75
x1011
2.49
x
1011
5.00
x
1011
7.51
x
1011
upstream
1.95
x
1010
2.77
x
1010
5.55
x
1010
8.34
x
1010
MOS
2.10
x
1010
3.01
x
1010
6.02
x
1010
9.03
x
1010
LC
2.16
x
1011
3.08
x
1011
6.16
x
1011
9.25
x
1011
Implementation
Strategy
The
narrative
standard
requires
that
the
WLA
for
human
sources
be
zero
and
that
BMPs
be
implemented
to
the
maximum
extent
practicable
(
MEP)
for
urban
storm
water.
The
designated
management
agencies
(
DMAs)
will
develop
a
bacteria
management
plan,
as
described
in
OAR
340­
41­
015,
that
will
include:

1.
CSO
Program:
This
program
will
reduce
the
occurrence
of
CSO
events
in
the
Columbia
Slough
with
a
variety
of
projects,
including
roof
drain
disconnection,
sewer
and
storm
water
separation,
and
construction
of
a
consolidation
conduit
and
wet
weather
treatment
facility
to
treat
storm
water.

5
log
mean
31
2.
Sanitary
surveys
of
septic
systems,
removal
of
direct
discharges
of
human
waste
to
the
Slough.
3.
Detect
and
eliminate
illicit
discharges
to
the
Slough
4.
Establish
adequate
monitoring
to
demonstrate
compliance
with
E.
coli
criteria,
including
measuring
E.
coli
concentrations
and
distributions.
5.
Implement
BMPs
to
control
anthropogenic
source
of
bacteria
in
storm
water.
6.
Implement
water
quality
management
plans
as
developed
as
part
of
the
Lower
Willamette
Subbasin
plan
(
projected
completion
spring
1999).

Instream
bacteria
monitoring
is
intended
to
meet
3
goals:

1.
assess
long
term
trending
2.
determine
spatial
distribution
of
bacteria
3.
determine
seasonal
distribution
of
bacteria
Results
of
the
monitoring
will
be
used
to
identify
bacteria
"
hot
spots"
that
require
further
investigation.

Industrial
storm
water
permittees
will
be
required
to
detect
and
eliminate
discharges
of
human
waste
to
the
Slough.
They
will
also
be
required
to
implement
BMPs
to
the
MEP
to
control
bacteria
loads
from
other
than
human
sources.

The
responsibilities
of
each
DMA
are
summarized
below,
by
reach:

Table
11:
Bacteria
Control
Summary
Reach
Control
Strategies
Responsible
DMA
1
1,2,3,4,5
City
of
Portland
1
2,3,4,5
PDX
2
2,3,4,5
City
of
Portland,
PDX
3
2,3,4,5
City
of
Portland,
City
of
Gresham
4
3,4,5
City
of
Fairview,
Multnomah
County
5
1­
5
1­
5
3,4,5
6
2,3,4,5
City
of
Fairview,
City
of
Gresham,
Multnomah
County,
City
of
Wood
Village
Oregon
Department
of
Agriculture
Oregon
Department
of
Transportation
Toxics
Water
Quality
Criteria
The
State
has
water
quality
criteria
for
toxics
that
are
intended
to
protect
both
aquatic
life
and
human
health.

OAR
340­
41­
445(
2)(
p)(
A):
Toxic
substances
shall
not
be
introduced
above
natural
background
levels
in
the
waters
of
the
state
in
amounts,
concentrations,
or
combinations
which
may
be
harmful,
may
chemically
change
to
harmful
forms
in
the
environment,
or
may
accumulate
in
sediments
or
bioaccumulate
in
aquatic
32
life
or
wildlife
to
levels
that
adversely
affect
public
health,
safety,
or
welfare;
aquatic
life;
wildlife;
or
other
designated
beneficial
uses;

OAR
340­
41­
445(
2)(
p)(
B):
Levels
of
toxic
substances
shall
not
exceed
the
criteria
listed
in
Table
20
which
were
based
on
criteria
established
by
EPA
and
published
in
Quality
Criteria
for
Water
(
1986),
unless
otherwise
noted;

OAR
340­
41­
445(
2)(
p)(
C):
.
.
.
Where
no
published
EPA
criteria
exist
for
a
toxic
substance,
public
health
advisories
and
other
published
scientific
literature
may
be
considered
and
used,
if
appropriate,
to
set
guidance
values.

The
Department
has
developed
five
conditions
to
interpret
and
apply
the
water
quality
criteria
and
determine
impact
on
a
beneficial
use:

A.
Water
Quality
Criteria
Violations
occur
if:
1.
The
freshwater
chronic
criteria
for
protection
of
aquatic
life
contained
in
OAR
Table
20
is
violated
more
than
10%
of
the
time
and
for
a
minimum
of
two
values.
For
hardness­
dependent
criteria,
the
criteria
will
be
calculated
based
on
the
instream
hardness
measured
at
the
time
of
sampling.
2.
The
chemical
is
found
in
sediments
at
levels
which
analytical
models
demonstrate
that
water
quality
standards
are
violated.
The
analysis
and
modeling
must
be
reviewed
and
approved
by
DEQ.

B.
Measure
of
impairment
of
a
Beneficial
Use
1.
A
fish
or
shellfish
consumption
advisory
or
recommendation
issued
by
the
Oregon
State
Health
Division
specifically
refers
to
this
chemical.
2.
The
chemical
has
been
found
to
cause
a
biological
impairment
via
a
field
test
of
significance
such
as
a
bioassay.
The
field
test
must
involve
comparison
to
a
reference
condition.
3.
The
chemical
has
been
detected
in
more
than
10%
of
available
fish
tissue
samples,
and
the
population
mean6
of
the
samples
exceeds
a
screening
value
derived
from
Table
20.
The
screening
value
is
developed
as
follows:
Fish
Tissue
Screening
Value
(
mg/
kg)
=
Table
20
Criteria
for
Protection
of
Human
Health(
ng/
l) 
BCF
(
l/
kg)
*(
mg/
106
ng)
where
BCF
=
Bioconcentration
Factor.
BCFs
were
obtained
from
the
EPA
Region
VIII
Criteria
Chart
(
July
1993).

The
OAR
Table
20
criteria
are
total
recoverable
metal
criteria
for
the
protection
of
freshwater
aquatic
life.
EPA
has
recommended
the
use
of
the
dissolved
fraction
of
the
6
Helsel's
method
is
used
for
calculating
the
population
mean
when
nondetects
are
present.
This
option
is
available
on
the
software
uncensored
v4.0
by
Michael
C.
Newman,
K.
Dawn
Greene,
&
Phillip
M.
Dixon
from
Savannah
River
Ecology
Laboratory,
Aiken,
South
Carolina.
To
simplify
the
initial
screening
for
the
statewide
303(
d)
list
the
condition
reads
"...
10%
of
available
fish
tissue
samples,
and
the
mean
of
the
detects
exceeds
a
screening
level
value
from
Table
20."
33
metal,
as
it
is
the
most
biologically
available
form
of
the
metal.
To
calculate
the
dissolved
Pb
criterion,
a
two
step
calculation
is
necessary;
adjust
the
criterion
for
hardness
and
utilize
a
conversion
factor.
The
hardness
correction
is
calculated
as
follows:

total
lead
criteria
=
e(
1.273[
ln(
hardness)]­
4.705)
(
EPA
1986)

A
conversion
factor
(
CF)
for
Pb
is
then
calculated
to
convert
the
criteria
to
the
dissolved
form
as
follows:

CF
=
1.46203
­
[
ln(
hardness)(
0.145712)]
(
EPA
1996)

If
the
hardness
is
measured
with
each
individual
sample,
a
conversion
factor
and
criterion
can
be
calculated
for
each
sample.

Pb
Monitoring
Instream
data
BES
has
collected
296
dissolved
Pb
and
hardness
samples
from
all
reaches
of
the
Slough,
throughout
all
seasons.
Using
the
hardness
measured
with
each
individual
sample,
a
conversion
factor
and
criterion
was
calculated
for
each
sample.
The
mean
of
the
individual
conversion
factors
is
0.82.
From
the
frequency
distribution
of
the
criteria
(
Figure
11),
the
5th
percentile
criterion
was
calculated
to
be
0.0012
mg/
L
Pb.
The
5th
percentile
represents
a
"
worst
case"
assumption
(
EPA,
1995).
As
seen
in
Figure
12,
approximately
16.7%
of
the
dissolved
Pb
samples
exceed
this
criterion
7.
When
the
samples
were
compared
with
their
respective
criterion,
10.4%
of
the
samples
exceed
the
criterion.

Dissolved
Pb
criteria,
frequency
distribution
0
10
20
30
40
50
60
0.001
0.0012
0.0014
0.0016
0.0018
0.002
0.0022
0.0024
0.0026
0.0028
0.003
More
frequency
0
10
20
30
40
50
60
70
80
90
100
Cumulative
frequency
Figure
11:
Dissolved
Pb
criteria,
frequency
distribution
7
296
samples,
non
­
detected
values
set
at
detection
limit
of
0.001
mg/
L
34
Dissolved
Pb
data
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0%
10%
20%
30%
40%
50%
60%
70%
80%
9
0%
10
0%

f
req
uenc
y
Pb,
mg/
L
Figure
12:
Instream
dissolved
Pb
data
frequency
distribution
(
includes
non
detects)

The
Columbia
Slough
is
water
quality
limited
for
the
metal
lead
(
Pb)
because
of
criteria
exceedance
in
the
water
column.

Sources
Unlike
the
conventional
pollutant
analyses,
detailed
modeling
for
toxics
with
CEQUAL
W2
has
not
been
conducted.
However,
potential
sources
of
Pb
to
the
Slough
have
been
analyzed.
Such
sources
include;
municipal
and
industrial
storm
water,
industrial
discharges,
CSOs,
contaminated
sites,
contaminated
sediment,
St.
John's
Landfill,
and
air
emissions.
The
analyses
to
estimate
the
Pb
loads
from
these
sources
are
contained
in
Appendix
A
(
sources
document).
Table
12
summarizes
the
estimates
of
total
lead
loads
to
the
Columbia
Slough.
35
Table
12:
Summary
of
Total
Pb
loads
to
the
Columbia
Slough
Source
Lead
(
kg/
yr)
Industrial
Discharges
0.19
Combined
Sewer
Overflows
75.7
Storm
water
(
total)
1131
MS4
area
only
9908
Industrial
permitted
area
only
141
Groundwater
Overall
loading
26
NuWay
Oil
Site
(
to
Whitaker
Slough)
groundwater
sediment
partitioning
soil
erosion­
process
area
soil
erosion
­
non
process
area
1.65
x
10­
5
27.1
0.438
0.005
St.
John's
Landfill
1.31
Miscellaneous
Sediment
Partitioning
0.030
Air
Deposition9
Oregon
Steel
wet
deposition
Oregon
Steel
dry
deposition
0.014
8.99
x
10­
7
Spills
estimate
not
available
Illicit
Discharges
estimate
not
available
Total
of
Estimates:
1262
With
non
detected
values
set
to
the
detection
limit,
instream
Pb
data
appears
to
be
close
to
the
chronic
criteria.
Estimates
of
Pb
loads
to
the
Slough
have
been
calculated
primarily
for
total
Pb,
not
dissolved.
These
estimates
indicate
that
storm
water
from
municipal
and
industrial
property
contributes
most
of
the
Pb
load.
However,
the
simple
method
(
EPA
1992)
used
to
develop
the
storm
water
load
estimates
does
not
account
for
processes
that
occur
during
transport
of
storm
water
to
the
Slough,
such
as
sedimentation
and
resuspension.
The
TMDL
will
focus
on
refining
estimates
of
loads
from
various
land
uses,
including
estimates
of
the
dissolved
Pb
load.

Loading
Capacity
and
Margin
of
Safety
Defined
As
stated
previously,
OAR
Table
20
criteria
are
defined
as
total
recoverable
metal.
In
the
monitoring
data
for
the
Columbia
Slough,
the
predominant
form
of
Pb
is
dissolved
Pb.
The
loading
capacity
and
allocations
are
calculated
to
meet
the
dissolved
Pb
criteria.
To
convert
the
allocations
to
total
recoverable
Pb,
the
values
can
be
divided
by
the
mean
of
the
conversion
factors
calculated
with
each
hardness
value
(
0.82).
The
loading
capacity
of
the
Columbia
Slough
for
Pb
is
defined
as
the
5th
percentile
aquatic
life
chronic
criteria
(
adjusted
for
hardness
and
converted
to
dissolved
8
The
calculated
total
Pb
load
minus
the
load
associated
with
industrial
areas.
9
Using
the
50th
percentile
mass
load.
36
form)
times
the
flow
in
the
Columbia
Slough.
A
baseflow
of
1.98
m3/
sec
(
groundwater
flow
only)
and
storm
flows
are
used
to
calculate
the
loading
capacity.
The
storm
flows
range
from
2.83­
8.50
m3/
sec,
approximating
the
range
of
flows
achieved
by
pumping
at
MCDD1.
As
described
previously,
the
load
estimates
were
calculated
as
average
annual
loads
of
total
Pb.
There
is
little
data
available
to
estimate
the
loads
as
dissolved
Pb,
or
to
model
the
fate
and
transport
of
Pb
in
storm
drains
and
instream.
In
Phase
I
of
the
TMDL,
the
allocations
are
based
on
dissolved
Pb
and
requirements
to
quantify
the
dissolved
Pb
load
from
the
sources
are
outlined.
Estimates
of
dissolved
Pb
loads
will
be
refined
in
the
next
phase
of
the
TMDL,
and
will
allow
for
allocations
based
on
these
estimates.

LC
(
kg/
day)
=
flow
(
m3/
sec)
x
5th
percentile
criterion
(
mg/
L)
x
conversion
factor
Using
the
5th
percentile
criterion
means
that
95%
of
the
field
samples
should
be
<
0.0012
mg/
L.
The
margin
of
safety
is
set
to
decrease
that
to
0.001
mg/
L
or
the
detection
limit.
This
effectively
means
that
only
5%
of
the
samples
to
be
measured
can
exceed
the
detection
limit.
The
difference
between
the
criterion
of
0.0012
mg/
L
and
the
detection
limit
of
0.001
mg/
L
is
0.0002
mg/
L.
This
concentration
is
multiplied
by
the
flow
and
subtracted
from
the
daily
loading
capacity.

Table
13:
Dissolved
Pb
Loading
capacity
Flow
(
m3/
sec)
5th
percentile
criteria
(
mg/
L)
LC
(
kg/
day)
MOS
(
mg/
L)
MOS
(
kg/
day)
LC
­
MOS
(
kg/
day)
Baseflow
1.98
0.0012
0.205
0.0002
0.034
0.171
Storm
flow
2.83
0.0012
0.293
0.0002
0.049
0.244
5.66
0.0012
0.587
0.0002
0.098
0.489
8.50
0.0012
0.881
0.0002
0.147
0.734
Allocations
An
analysis
was
performed
to
determine
if
there
are
obvious
spatial
trends
with
the
Pb
data.
Figure
13
shows
a
comparison
of
dissolved
lead
levels
in
the
different
reaches
of
the
Columbia
Slough.
Figure
14
shows
the
distribution
of
Pb
levels
in
sediment
in
the
Columbia
Slough.
37
Comparison
of
Water
Column
Pb
Levels
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0
2
4
6
8
10
12
14
16
18
20
River
Mile
Dissolved
Pb
(
mg/
L)

Reach
1
Reach
2
Reach
3
Buffalo
Slough
MCDD4
Whitaker
Slough
Figure
13:
Instream
dissolved
Pb
0
50
100
150
200
250
0
2
4
6
8
10
12
14
16
18
20
River
Mile
Level
in
Sediment
(
mg/
kg)
Reach
1
Reach
2
Reach
3
Figure
14:
Pb
levels
in
sediment
in
the
Columbia
Slough
Higher
concentrations
in
the
upper
end
of
the
Lower
Slough
(
Reach
1)
may
be
due
to
net
inflow
of
sediment
from
the
Willamette
(
Li,
1995).
Allocations
will
be
set
for
the
entire
Slough
until
spatial
distribution
can
be
better
defined.
38
Allocations
were
calculated
using
flows,
concentrations
and
estimates
of
annual
loads
as
described
in
Appendix
A.
The
allocations
apply
annually.

Industrial
Point
Source
Discharge:
The
waste
load
for
the
one
point
source
discharge
is
set
at
the
current
estimated
load
of
5
x
10­
4
kg/
day.

CSOs:
Because
they
are
scheduled
for
removal,
CSOs
receive
a
waste
load
allocation
of
zero
kg/
yr
except
for
one
in
10
year
summer
event
and
1
in
5
year
winter
event.

St.
John's
landfill:
Pb
in
ground
water
from
St.
John's
landfill
is
set
at
the
estimate
of
the
current
load
of
3.6
x
10­
3
kg/
day.

Ground
water:
Pb
in
ground
water
is
set
at
the
current
estimated
load
of
0.07
kg/
day.

Sediment
Partitioning:
Sediment
partitioning
and
diffusive
flux
allocation
is
set
by
multiplying
the
estimated
water
column
concentration
(
in
Table
15
in
Appendix
A)
by
the
base
flow
and
storm
flows
through
the
Columbia
Slough.
As
stated
in
Appendix
A,
the
estimated
water
column
Pb
concentration
from
partitioning
is
2.056
x
10­
7
mg/
L.
1.98
m3/
sec
x
2.056
x
10­
7
mg/
L
x
1000
L/
m3
x
1
kg/
106
mg
x
60
sec/
min
x
60
min/
hr
x
24
hr/
day
=
3.52
x
10­
5
kg/
day
This
calculation
is
done
for
each
of
the
storm
flows
as
well.

Air
deposition:
The
allocation
for
the
single
air
source
is
set
at
the
estimate
of
the
current
load;
wet
and
dry
deposition.
Total
deposition
=
(
0.014
kg/
yr
+
8.99
x
10­
7
kg/
yr)
=
0.014
kg/
yr
=
3.84
x
10­
5
kg/
day
NuWay
Oil
Site:
The
NuWay
Oil
Site
receives
an
allocation
for
each
of
the
contributing
sources;
groundwater,
sediment
partitioning
and
surface
runoff.
The
surface
runoff
allocation
is
addressed
in
the
storm
water
section.
Ground
water
from
NuWay
Oil
is
allocated
at
its
current
load
of
4.53
x
10­
8
kg/
day.
Sediment
partitioning
at
the
NuWay
Oil
Site
receives
an
allocation
with
a
concentration
equivalent
to
the
instream
concentration
contributed
by
the
median
of
all
the
contaminated
sediment
in
the
Slough.
The
instream
median
concentration
was
2.056
x
10­
7
mg/
L
(
see
Appendix
A).
This
concentration
was
multiplied
by
estimates
of
baseflow
and
storm
flow
within
Whitaker
Slough.
These
flows
were
0.81
m3/
sec,
0.91
m3/
sec,
1.21
m3/
sec
and
1.53
m3/
sec
(
corresponding
to
flows
of
1.98,
2.83,
5.66
and
8.5
m3/
sec
in
the
main
stem
of
the
Columbia
Slough)
(
Scott
Wells,
personal
communication)

Storm
water:
The
allocations
that
are
set
at
current
loads
and
the
margin
of
safety
were
subtracted
from
the
loading
capacity.
This
remaining
capacity
is
divided
between
future
growth
and
storm
water
runoff.
Current
storm
water
loads
are
given
2/
3
of
the
Pb
allocation
and
future
growth
receives
1/
3
of
the
Pb
allocation.
Individual
storm
water
sources
will
calculate
their
allocation
on
a
unit
area
basis.
39
For
example,
the
sum
of
the
allocations
for
the
industrial
discharge,
ground
water,
St.
Johns'
landfill,
air
deposition,
sediment
partitioning,
and
groundwater
and
sediment
partitioning
at
NuWay
oil
and
the
margin
of
safety
equals
0.108
kg/
day
(
for
the
allocations
at
1.98
m3/
sec).
Subtracting
this
from
the
loading
capacity
of
0.205
kg/
day
leaves
0.097
kg/
day
to
be
allocated
to
future
growth
and
storm
water.
Future
growth
receives
1/
3
of
this
allocation
or
0.031
kg/
day
and
storm
water
receives
2/
3
or
0.065
kg/
day.
Storm
water
allocations
will
be
calculated
on
a
unit
area
basis,
for
each
flow.
At
1.98
m3/
sec,
the
storm
water
allocation
is
0.065
for
the
entire
Slough
drainage
basin.
The
basin
is
about
40,000
acres
or
1.62
x
108
m2
.
The
unit
area
allocation
is
then:
0.065
kg/
day/
1.62
x
108
m2
=
4.01
x
10­
10
kg/
day/
m2
To
determine
an
allocation
for
storm
water
runoff
from
the
NuWay
oil
site,
the
area
of
the
site
is
multiplied
by
the
unit
area
allocation.
The
calculation
is
as
follows:

NuWay
Oil
site
process
and
non
process
area
=
60,
000
ft2
x
1m2/
10.76
ft2
=
5576
m2
The
allocation
for
surface
runoff
from
NuWay
Oil
Site
is:
(
5576
m2)
x
(
4.01
x
10­
10
kg/
day/
m2)
=
2.24
x
10­
6
kg/
day
Table
14:
Pb
allocations
Source
Allocations
(
kg/
day)
10
1.98
m3/
sec
2.83
m3/
sec
5.66
m3/
sec
8.50
m3/
sec
Industrial
discharge
5.4
x
10­
4
5.4
x
10­
4
5.4
x10­
4
5.4
x
10­
4
CSO
0
0
0
0
sediment
partitioning
3.52
x
10­
5
1.0
x
10­
4
1.0
x
10­
4
2.0
x
10­
4
groundwater:
overall
St.
John's
landfill
0.07
3.6
x
10­
3
0.07
3.6
x
10­
3
0.07
3.6
x
10­
3
0.07
3.6
x
10­
3
air
deposition
3.84
x
10­
5
3.84
x
10­
5
3.84
x
10­
5
3.84
x
10­
5
NuWay
Oil
Site
sediment
partitioning
soil
erosion
groundwater
1.45
x
10­
5
2.24
x10­
6
4.53
x
10­
8
1.6
x
10­
5
2.24
x
10­
6
4.53
x
10­
8
2.17x
10­
5
2.24
x
10­
6
4.53
x
10­
8
2.7
x
10­
5
2.24
x
10­
6
4.53
x
10­
8
Future
growth
0.031
0.055
0.1382
0.2199
storm
water
0.065
0.114
0.2765
0.4397
MOS
0.0348
0.0497
0.098
0.147
LC
0.205
0.293
0.587
0.881
Implementation
Strategy
Pb
levels
in
the
Slough
exceed
the
aquatic
life
chronic
criteria,
however,
the
instream
Pb
data
include
many
values
that
are
at
the
detection
limit
and
are
much
lower
than
the
practical
quantification
limit.
As
seen
below,
most
of
the
samples
(
245/
296)
are
lower
than
the
criteria
and
the
detection
level.

10
Excess
loading
capacity
was
allocated
to
the
margin
of
safety.
40
Table
15:
Comparison
of
detection
level
and
criteria
exceedance
detection
level
(
0.001
mg/
L)

dissolved
criteria
less
than
greater
than
less
than
245
19
greater
than
1
31
Additionally,
an
analysis
of
the
relative
criteria
exceedance
on
wet
and
dry
days
revealed
that
the
wet
day
exceedance
rate
(
10.9%)
was
not
different
than
the
dry
day
exceedance
(
10.8%).
In
this
analysis,
a
wet
day
was
defined
as
one
in
which
the
cumulative
rainfall
on
that
day
and
the
three
days
prior
exceeded
0.25
inches.
Modeling
of
loads
indicate
that
storm
water
is
the
largest
contributor
of
Pb,
however,
the
loads
would
be
expected
to
result
in
higher
instream
Pb
levels
than
what
is
observed.
Modeling
by
Wells
(
1997)
indicates
that
storm
water
is
diluted
about
2
times
in
the
Slough.
There
are
no
synoptic
data
sets
linking
storm
water
loads
with
instream
values.
Examination
of
the
Portland
MS4
permit
reveals
that
commercial,
industrial
and
traffic
corridor
land
uses
contribute
the
largest
loads
of
Pb
(
unit
load
basis),
respectively.
BMPs
should
be
developed
based
on
land
uses,
but
further
delineation
of
sources
based
on
land
use
must
be
done.
Under
Phase
I
of
the
Pb
TMDL,
DMAs
will
be
required
to
develop
the
synoptic
data
sets.
A
lower
detection
limit
for
the
analysis
will
also
be
required
to
gain
a
better
understanding
of
when
and
how
frequently
the
criteria
is
being
violated.
Phase
I
will
also
include
measuring
the
effectiveness
of
controls
at
reducing
the
lead
load
from
storm
water.
The
requirements
for
all
potential
contributors
of
lead
are
outlined
below.

Industrial
permittee
requirements
The
DEQ
anticipates
requiring
implementation
of
BMPs
through
storm
water
permits.
A
basin
specific
general
storm
water
permit
will
be
developed
by
DEQ
to
address
all
303(
d)
pollutants.
Requirements
of
this
permit
to
reduce
the
lead
load
are
as
follows:
1.
Monitoring
for
total
and
dissolved
lead
2.
Implementation
of
BMPs
to
control
or
remove
metals.
3.
Monitor
effectiveness
of
BMPs.

Environmental
Cleanup
Sites
DEQ's
Site
Response
section
has
conducted
a
review
of
the
sites
in
the
Environmental
Cleanup
Site
Information
(
ECSI)
database
to
determine
which
of
those
merit
increased
attention
due
to
the
presence
of
303(
d)
chemicals
and
proximity
to
the
Slough.
High
priority
sites
have
been
moved
to
the
cleanup
program.
DEQ
water
quality
program
will
develop
a
monitoring
protocol
to
be
included
in
the
statement
of
work
for
site
cleanup
to
estimate
the
load
of
303(
d)
pollutants
from
individual
sites.
The
individual
project
managers
will
select
BMPs
for
surface
runoff
control
and
metals
control
and
require
BMP
implementation.
41
Designated
Management
Agencies
1.
Conduct
instream
dry
and
storm
event
monitoring
for
total
lead,
dissolved
lead
and
hardness.
Conduct
lead
analysis
using
detection
levels
which
are
lower
than
the
water
quality
chronic
criterion.
2.
Conduct
monitoring
at
outfalls
to
Slough,
outfalls
selected
based
on
land
uses
known
to
have
high
lead
levels
or
other
metals.
3.
Identify
and
implement
BMPs
in
the
municipal
NPDES
permits
that
will
be
effective
in
controlling
lead
storm
water
inputs.
4.
Monitor
to
determine
effectiveness
of
BMPs
to
remove
total
and
dissolved
lead
from
storm
water.
5.
Estimate
the
load
reduction
of
lead
achieved
for
storm
water
at
the
end
of
Phase
I.
6.
Estimate
effectiveness
of
BMPs
to
remove
TSS.

The
responsibilities
of
the
DMAs,
by
reach,
is
summarized
below:

Table
16:
Lead
Control
Summary
Reach
Control
Strategy
Responsible
DMA
1
1,2,3,4,5,6
City
of
Portland,
PDX
2
1,2,3,4,5,6
City
of
Portland,
PDX
3
1,2,3,4,5,6
City
of
Portland,
City
of
Gresham
4
3,6
City
of
Fairview,
Multnomah
County
5
1­
5
3,6
1,2,3,4,5,6
City
of
Fairview,
City
of
Gresham,
Multnomah
County,
City
of
Wood
Village
Oregon
Department
of
Transportation
Organics
Monitoring
Fish
tissue
sampling
Fish
tissue
data
provide
the
most
extensive
evidence
of
impairment
of
beneficial
uses
by
toxics
in
the
Columbia
Slough.
Most
of
the
available
fish
tissue
data
were
collected
in
the
summer
of
1994
as
part
of
the
sediment
remediation
project
undertaken
by
BES.
Different
organisms
can
be
expected
to
bioaccumulate
chemicals
differently
based
on
age,
life
cycle
patterns,
amount
of
fatty
tissue
and
feeding
habits.
However,
since
bioconcentration
factors
are
generally
available
for
specific
chemicals
rather
than
for
specific
species,
results
for
the
different
species
tested
have
been
grouped
together.
The
BCFs
used
to
develop
screening
values
were
obtained
from
the
EPA
Region
VIII
Criteria
Chart
(
July
1993).
Fish
tissue
screening
values
can
be
calculated
directly
from
the
OAR
Table
20
criteria
as
follows:

Fish
Tissue
Screening
Value
(
mg/
kg)
=
Table
20
Criteria
for
protection
of
human
health
(
ng/
L)
 
BCF
(
L/
kg)
*
(
mg/
106
ng)

Screening
values
were
exceeded
for
DDT,
dieldrin,
and
PCBs.
Table
17
contains
a
summary
of
the
monitoring
results
for
these
chemicals.
In
August
1995,
the
Oregon
Health
Division
issued
a
fish
consumption
advisory
for
PCBs
and
DDT/
DDE.
42
Table
17:
Summary
of
Fish
Tissue
Exceedances
of
OAR
Table
20­
derived
screening
values
Chemical
Screening
Value
(
ug/
kg)
No.
of
values
No.
of
detects(%
of
total
samples)
No.
of
exceedances
(%
of
total
samples)
4,4'
DDT
1.29
65
15
(
23.1%)
15
(
23.1%)
aroclor
1248
(
PCB)
2.46
55
6
(
10.9%)
6
(
10.9%)
dieldrin
3.5
61
24
(
39.3%)
24
(
39.3%)

Polychlorinated
dibenzodioxins
(
dioxins)
refers
to
a
group
of
highly
toxic
compounds
that
are
generally
found
together
in
complex
mixtures
of
congeners
(
Parametrix,
July
5,
1995).
Congeners
are
compounds
formed
of
the
same
elements
that
have
different
molecular
structures.
In
the
case
of
the
various
dioxin
congeners,
the
chlorine
substitution
occurs
in
different
locations
on
the
base
molecule.
Table
20
of
the
water
quality
standards
contains
one
criterion
value
for
dioxin,
and
it
is
for
the
most
toxic
congener
known
as
2,3,7,8­
TCDD.
The
results
of
fish
tissue
data
for
2,3,7,8
TCDD
are
shown
in
Table
18.

Table
18:
Summary
of
Dioxin
Results
for
Fish
Tissue
Location
Collected
By
Date
of
Collection
Value
(
ng/
kg)
Detection
Limit
(
ng/
kg)
Lower
Slough
(
above
N.
Slough)
DEQ,
National
Bioaccumulation
Study
July
1987
2.86
not
reported
Lower
Slough
(
at
SP&
S
bridge)
DEQ,
National
Bioaccumulation
Study
July
1987
7.66
not
reported
Lower
Slough
(
river
mile
0­
3)
Parametrix,
for
BES
Summer,
1994
0.97
not
reported
Lower
Slough
(
river
mile
6­
8.6)
Parametrix,
for
BES
Summer,
1994
ND
1.0
Upper
Slough
(
River
mile
0­
3)
Parametrix,
for
BES
Summer,
1994
ND
0.8
Whitaker
Slough
Parametrix,
for
BES
Summer,
1994
ND
2.1
North
Slough
Parametrix,
for
BES
Summer,
1994
ND
0.9
Parametrix
samples
are
composite
samples.

The
screening
value
for
dioxin
is
0.07
ng/
kg.
As
seen
in
the
above
table,
3
of
the
7
samples
collected
exceed
this
screening
value.
To
summarize,
the
Columbia
Slough
is
considered
water
quality
limited
for
PCBs,
DDT/
DDE
and
dioxin
due
to
elevated
fish
tissue
levels.
Fish
tissue
data
indicates
elevated
levels
of
dieldrin,
so
a
preventative
TMDL
has
been
calculated
for
dieldrin
as
well.
An
analysis
of
the
sources
of
the
organics
is
contained
in
Appendix
A.

Loading
Capacity
Defined
For
phase
I
of
the
TMDL
process
the
fish
consumption
criteria
to
protect
human
health
is
used.
For
a
long
term
exposure,
EPA
recommends
the
use
of
harmonic
mean
flow
for
instream
flow.
Due
to
the
lack
of
data
to
calculate
harmonic
mean
flow,
the
annual
average
flow
is
used
as
an
estimate
of
long
term
flow.
According
to
the
Waterbody
43
Assessment
(
CH2MHill,
1995),
the
total
annual
inflow
to
the
Columbia
Slough,
not
counting
tidal
inflow
from
the
Willamette,
is
1.48
x
108
m3/
yr.
The
loading
capacity
is
calculated
as
follows:

total
annual
inflow
(
m3
/
yr)
x
Table
20
criteria
(
ng/
L)
x
(
1000
L/
m3)
x
1
yr/
365
days
x
1kg/
1012
ng
=
loading
capacity
(
kg/
day)

The
Table
20
criterion
for
DDT
is
used
for
DDT
and
DDE.
The
following
table
lists
the
OAR
Table
20
criteria
for
the
protection
of
human
health
and
the
corresponding
LCs
for
the
303(
d)
organics.

Table
19:
OAR
Table
20
Criteria11
and
LCs
for
303(
d)
Organics
Parameter
Criteria
(
ng/
l)
LC
(
kg/
day)
DDT/
DDE
0.024
9.73
x
10­
6
Dieldrin
0.071
2.88
x
10­
5
Dioxin
(
2,3,7,8­
TCDD)
1.3
x
10­
5
5.27
x
10­
9
PCBs
0.079
3.2
x
10­
5
Allocations
The
difference
between
the
loading
capacity
and
the
WLA
for
sediment
partitioning
and
diffusive
flux
(
from
Table
15
in
Appendix
A)
will
be
split
evenly
into
WLAs
for
total
urban
storm
water
and
the
MOS.
The
total
urban
storm
water
allocation
is
further
divided
to
account
for
future
growth
which
may
expose
soils
containing
the
organics,
as
well
as
current
storm
water
loads.
The
storm
water
allocation
also
includes
the
ECSI
sites.
As
ECSI
sites
or
new
storm
water
sources
are
identified,
they
will
receive
an
allocation
based
on
unit
area.

WLA
for
MOS
=
1/
2
x
(
LC
­
WLA
for
sediment
partitioning)
WLA
for
total
urban
storm
water
=
1/
2
x
(
LC
­
WLA
for
sediment
partitioning)
Future
growth
WLA
=
1/
3
total
urban
storm
water
allocation
Current
storm
water
WLA
=
2/
3
total
urban
storm
water
allocation
The
calculations
for
DDE/
DDT
are
summarized
as
an
example.
According
to
Table
15,
Appendix
A,
sediment
partitioning
contributes
4.87
x
10­
13
mg/
L
DDT
to
the
water
column.
This
concentration
is
converted
to
a
mass
load
as
follows:

(
4.87
x
10­
13
mg/
L)
x
(
1.48
x
108
m3/
yr)
x
(
1000L/
m3)
x
(
1
kg/
106
mg)
x
(
1
yr/
365
days)
=
1.97
x
10­
10
kg/
day
The
same
calculation
for
DDE
yields
a
mass
load
of
2.91
x
10­
10
kg/
day
of
DDE
to
the
water
column.
The
total
mass
load
for
DDT/
DDE
is
4.88
x
10­
10
kg/
day.

The
WLA
for
MOS
=
½
x
(
9.73
x
10­
6
kg/
day
 
4.88
x
10­
10
kg/
day)
=
4.86
x
10­
6
kg/
day
11
criteria
for
the
protection
of
human
health,
water
and
fish
ingestion
44
The
WLA
for
total
urban
storm
water
=
4.86
x
10­
6
kg/
day.
The
WLA
for
future
growth
=
1/
3
x
(
4.86
x
10­
6
kg/
day)
=
1.62
x
10­
6
kg/
day
The
WLA
for
storm
water
(
current)
=
2/
3
x
(
4.86
x
10­
6
kg/
day)
=
3.24
x
10­
6
kg/
day
NuWay
Oil
Site
Storm
water
runoff
allocation:
For
PCBs
the
storm
water
allocation
is
5.3
x
10­
6
kg/
day
for
the
entire
Slough
drainage
basin.
The
basin
is
about
40,000
acres
or
1.62
x
108
m2
.
The
unit
area
allocation
is
then
5.3
x
10­
6
kg/
day/
1.62
x
108
m2
=
3.27
x
10­
14
kg/
day/
m2.
To
determine
an
allocation
for
storm
water
runoff
from
the
NuWay
oil
site
for
PCBs,
the
area
of
the
site
is
multiplied
by
the
unit
area
allocation.
The
calculation
is
as
follows:

NuWay
Oil
site
process
and
non
process
area
=
60,
000
ft2
x
1m2/
10.76
ft2
=
5576
m2
The
allocation
for
surface
runoff
from
NuWay
Oil
Site
is:
(
5576
m2)
x
(
3.27
x
10­
14
kg/
day/
m2)
=
1.82
x
10­
10
kg/
day
No
allocations
were
calculated
for
the
other
organics
as
they
have
not
been
found
at
the
site.

No
estimates
of
dioxin
loads
from
sediment
partitioning
are
available,
so
the
loading
capacity
is
divided
evenly
between
the
three
sources
and
the
margin
of
safety.
The
waste
load
allocations
are
annual
and
summarized
as
follows:

Table
20:
Organic
Allocations
(
kg/
day)
12
Parameter
LC
LA
sediments
WLA
storm
water
WLA
Future
Growth
MOS13
NuWay
Oil
DDT/
DDE
9.73
x
10­
6
4.88
x
10­
10
3.24
x
10­
6
1.62
x
10­
6
4.87
x
10­
6
N/
A
dieldrin
2.88
x
10­
5
1.08
x
10­
8
9.6
x
10­
6
4.8
x
10­
6
1.43
x
10­
5
N/
A
dioxin
5.27
x
10­
9
1.31
x
10­
9
1.31
x
10­
9
1.31
x
10­
9
1.34
x
10­
9
N/
A
PCBs
3.2
x
10­
5
1.61
x
10­
7
5.3
x
10­
6
1.06
x
10­
5
1.59
x
10­
5
1.82
x
10­
10
Implementation
Strategy
Monitoring
as
part
of
the
Buffalo
Slough
sediment
remediation
project
has
indicated
that
the
largest
contributor
of
PCBs
to
the
Buffalo
Slough
is
sediment
in
storm
water,
while
storm
water
contributes
pesticides.
The
organics
present
in
fish
tissue
in
the
Columbia
Slough
are
not
the
result
of
continuing
use
of
the
chemicals,
but
previous
use
and
application.
The
TMDL
strategy
focuses
on
implementation
of
BMPs
to
control
erosion
in
the
Slough
basin
and
monitoring
to
evaluate
their
effectiveness.
This
strategy
is
based
on
limited
data
indicating
that
control
of
sediment
input
to
the
Columbia
Slough
will
reduce
the
organic
load.

12
Due
to
rounding,
sum
of
WLA
may
not
equal
LC
(
but
does
not
exceed
LC).
For
dioxin
excess
LC
was
allocated
to
the
MOS.
13
Excess
loading
capacity
is
allocated
to
the
MOS
in
the
allocation
table.
45
Industrial
Storm
water
permits
The
DEQ
anticipates
requiring
implementation
of
BMPs
through
storm
water
permits.
A
basin
specific
general
storm
water
permit
will
be
developed
by
DEQ
to
address
all
303(
d)
pollutants.
Requirements
to
reduce
the
organic
load
from
industrial
storm
water
will
be
as
follows:
1.
Monitoring
for
TSS.
2.
Implementation
of
BMPs
to
control
erosion
and
sedimentation.
3.
Monitor
effectiveness
of
BMPs
at
erosion
and
sedimentation
control.

Environmental
Cleanup
Sites
DEQ's
Site
Response
section
has
conducted
a
review
of
the
sites
in
the
Environmental
Cleanup
Site
Information
(
ECSI)
database
to
determine
which
of
those
merit
increased
attention
due
to
the
presence
of
303(
d)
chemicals
and
proximity
to
the
Slough.
High
priority
sites
have
been
moved
to
the
cleanup
program.
DEQ
water
quality
program
will
develop
a
monitoring
protocol
to
be
included
in
the
statement
of
work
for
site
cleanup
to
estimate
the
load
of
303(
d)
pollutants
from
individual
sites.
The
individual
project
managers
will
select
BMPs
for
surface
runoff
control
and
require
BMP
implementation.

Designated
Management
Agencies
1.
Conduct
pilot
monitoring
projects
to
determine
the
relationship
between
TSS
and
organics
in
storm
water.
2.
Identify
and
implement
BMPs,
as
listed
in
the
municipal
NPDES
permits,
for
erosion
control
based
on
limited
data
suggesting
storm
water
sediment
as
a
current
source
of
organics.
3.
Monitor
the
effectiveness
of
BMPs
at
TSS
removal.
4.
Estimate
the
load
reduction
of
TSS
achieved
for
storm
water
at
the
end
of
Phase
I.
5.
Implement
water
quality
management
plans
as
developed
as
part
of
the
Lower
Willamette
Subbasin
plan.

The
responsibilities
of
the
DMAs,
by
reach,
is
summarized
below:

Table
21:
Organic
Control
Summary
Reach
Control
Strategy
Responsible
DMA
1
2,3,4
City
of
Portland,
PDX
2
(
Buffalo
Slough)
1
City
of
Portland
(
as
part
of
sediment
remediation
project
for
Buffalo
Slough)
2
2,3,4
City
of
Portland,
PDX
3
2,3,4
City
of
Portland,
City
of
Gresham
4
2
City
of
Fairview,
Multnomah
County
5
1­
5
1­
5
2
5
2,3,4
City
of
Fairview,
City
of
Gresham,
Multnomah
County,
City
of
Wood
Village
Oregon
Department
of
Agriculture
Oregon
Department
of
Transportation
46
REFERENCES
Berger,
Chris,
draft
memo
to
DEQ,
Columbia
Slough
eutrophication
model
runs,
Portland
State
University,
May
15,
1998.

BES,
Columbia
Slough
Planning
Study
Background
Report,
City
of
Portland,
February
1989.

Biorn­
Hansen,
Sonja,
personal
communication,
May
14,
1997,
DEQ,
discussion
of
field
shading
estimates.

Chapra,
Steven,
C.,
Surface
Water
Quality
Modeling,
1997,
McGraw
Hill
Companies,
Inc.,
pp.
245.

CH2MHill,
1995,
Water
Body
Assessment,
Columbia
Slough
TMDL
Development,
Part
I,
prepared
for
City
of
Portland,
November
1995.

CH2MHill,
1995,
Water
Body
Assessment,
Columbia
Slough
TMDL
Development,
Part
II,
prepared
by
CH2MHill
for
City
of
Portland,
November
1995.

Cole,
T.
and
Buchak,
E.,
CE­
QUAL­
W2
User's
Manual
,
Corps
of
Engineers,
Waterways
Experiments
Station,
Vicksburg,
Mississippi,
1994.

Corps
of
Engineers,
CE­
QUAL­
W2:
A
Numerical
Two­
Dimensional,
Laterally
Averaged
Model
of
Hydrodynamics
and
Water
Quality:
User's
Manual,
Environmental
and
Hydraulics
Laboratory,
Waterways
Experiments
Station,
Vicksburg,
Mississippi,
1986.

Corps
of
Engineers,
Draft
­
Updated
CE­
QUAL­
W2
User's
Manual,
Waterways
Experiments
Station,
Vicksburg,
Mississippi,
1990.

DEQ
1996,
DEQ's
1994/
96
303(
d)
List
Supporting
Documents:
Decision
Matrix;
Criteria
Used
for
Listing
Waterbodies;
Glossary;
Bibliography,
Oregon
Department
of
Environmental
Quality,
July
1996.

East
Multnomah
County
Sanitary
Sewer
Consortium,
1995
Annual
Cesspool
Removal
Report
for
the
Mid
County
Sewer
Project.

Environmental
Quality
Commission,
In
the
Matter
of
the
Proposal
to
Declare
a
Threat
to
Drinking
Water
in
a
Specifically
Defined
area
in
Mid­
Multnomah
County
Pursuant
to
ORS
454.275
et.
seq.,
Findings
and
Recommendations,
1/
30/
86
Environmental
Protection
Agency
(
EPA),
Quality
Criteria
for
Water,
Office
of
Water,
Regulations
and
Standards,
EPA
440/
5­
86­
001,
1986.
47
Environmental
Protection
Agency
(
EPA),
Office
of
Water,
Guidance
Manual
for
the
Preparation
of
Part
2
of
the
NPDES
Permit
Applications
for
Discharges
from
Municipal
Separate
Storm
Sewer
Systems,
EPA
833­
B­
92­
002,
November
1992.

Environmental
Protection
Agency
(
EPA)
Region
VIII,
CWA
Section
304(
a)
Criteria
Chart,
indicating
published
criteria
and
updated
human
health
values,
current
as
of
July
1,
1993.

Environmental
Protection
Agency
(
EPA),
The
Metals
Translator:
Guidance
for
Calculating
A
Total
Recoverable
Permit
Limit
from
a
Dissolved
Criterion,
Office
of
Water,
EPA
823­
B­
96­
007,
June
1996.

Environmental
Protection
Agency
(
EPA),
Use
of
Ambient
Data
and
Antidegradation
in
Calculating
Wasteload
Allocations,
memo,
Wastewater
Management
and
Enforcement
Branch,
July
1995.

Gresham
NPDES
MS4
permit
No.
101315
Annual
Report,
City
of
Gresham
and
copermittees
August
30,
1996.

Li,
Shu­
Guang,
Columbia
Slough
Sediment
Transport
Study
Results
and
Summary
of
Key
Findings,
Prepared
for
Parametrix,
Inc.
and
the
City
of
Portland
Bureau
of
Environmental
Services,
Prepared
by
Portland
State
University,
1995.

LTI,
Technical
Memorandum
and
Excel
spreadsheet,
Evaluation
to
estimate
the
effect
that
dispersion
may
have
on
dissolved
oxygen
modeling
conducted
to
develop
the
Columbia
Slough
TMDL,
July
1,
1997.

Portland
MS4
NPDES
Municipal
Storm
water
Permit
Annual
Compliance
Report,
submitted
by
City
of
Portland
and
co­
permittees,
September
1,
1996.

Portland
MS4
NPDES
Municipal
Storm
water
Permit
Application,
Volume
II,
submitted
by
City
of
Portland
and
co­
applicants,
prepared
by
Woodward
Clyde
Consultants,
May
17,
1993.

Tchobanoglous,
George,
Schroeder,
Edward,
D.,
Water
Quality,
1985,
Addison­
Wesley
Publishing
Company,
pp.
115.

Thomann,
Robert,
V.,
Mueller,
John,
A.,
Principles
of
Surface
Water
Quality
Modeling
and
Control,
1987,
Harper
and
Row
Publishers,
pp.
306.

The
East
County
Sanitary
Sewer
Consortium:
Central
County
Service
District,
City
of
Gresham,
City
of
Portland,
City
of
Troutdale,
Threat
to
Drinking
Water
Findings,
June
1984.

U.
S.
Geological
Survey,
Water
Resources
Investigations
Report
96­
4234,
Occurrence
of
Selected
Trace
Elements
and
Organic
Compounds
and
Their
Relation
to
Land
Use
in
the
Willamette
River
Basin,
Oregon,
1992­
1994,
by
Chauncey
W.
Anderson,
Frank
A.
Rinella,
and
Stewart
A.
Rounds,
1996.
48
Water
Quality
Standards
Review,
Final
Issue
Paper
for
Temperature,
DEQ,
June
1995.

Wells,
Scott,
A.
Berger,
Chris,
J.,
Hydraulic
and
Water
Quality
Modeling
of
the
Upper
and
Lower
Columbia
Slough:
Model
Calibration,
Verification
and
Management
Alternatives
Report,
Technical
Report
Submitted
to
HDR
Engineering
and
City
of
Portland,
1993.

Wells,
Scott,
A.,
Berger,
Chris,
J.,
Upper
and
Lower
Slough
Water
Level
Test:
September
1
through
October
29,
1993,
Technical
Report
EWR­
2­
94,
Department
of
Civil
Engineering,
Portland
State
University,
1994.

Wells,
Scott,
A.,
Berger,
Chris,
J.,
Hydraulic
and
water
quality
modeling
of
the
upper
and
lower
Columbia
Slough:
model
calibration,
verification,
and
management
alternatives
report
for
1992­
1995,
Technical
Report
EWR­
2­
95,
Portland
State
University,
1995.

Wells,
Scott,
A.,
Berger,
Chris,
J.,
Upper
and
Lower
Columbia
Slough
Water
Level
Test
and
Winter
Sampling
Analysis:
June
1994
through
March
1995,
Technical
Report
EWR­
3­
95,
Portland
State
University,
1995.

Wells,
Scott,
Berger,
Chris,
PSU
Civil
Engineering
Department,
Memo
to
Mary
Abrams,
BES,
Dawn
Saunders,
CH2MHill,
Sonja­
Biorn
Hansen,
DEQ,
Tim
Hayford,
MCDD1,
Re:
Upper
Columbia
Slough
Shading,
September
27,
1995.

Wells,
Scott,
A.,
Berger,
Chris,
J.,
Eberle,
Michael,
B.,
Modeling
and
Monitoring
the
Columbia
Slough
System:
1995/
1996,
Technical
Report
EWR­
01­
96,
Portland
State
University,
August
1996.

Wells,
Scott,
A.,
Berger,
Chris,
J.,
Abrams,
Mary,
Winter
Storm
Event
Impacts
on
Dissolved
Oxygen
Levels
in
the
Columbia
Slough
System,
Proceedings
Second
Annual
Pacific
Northwest
Water
Issues
Conference:
The
Flood
of
1996,
October
7,8,
Portland,
Oregon.

Wells,
Scott,
A.,
Berger,
Chris,
Memo
to
BES
and
DEQ,
Re:
results
of
Columbia
Slough
system
high
phosphorus
load
and
winter
tracer
model
simulations,
April
21,
1997.

Wells,
Scott,
A.,
Annear,
Robert,
Memo
to
BES,
BOD
Levels
in
the
Columbia
Slough,
prepared
for
the
City
of
Portland,
Bureau
of
Environmental
Services,
August
21,
1997.
49
Temperature
Analysis
Water
Quality
Criteria
To
accomplish
the
goals
identified
in
OAR
340­
41­
120(
11),
unless
specifically
allowed
under
a
Department
approved
surface
water
temperature
management
plan
as
required
under
OAR
340­
41­
026(
3)(
a)(
D),
no
measurable
surface
water
temperature
increase
resulting
from
anthropogenic
activities
is
allowed:
(
i)
In
a
basin
for
which
salmonid
fish
rearing
is
a
designated
beneficial
use,
and
in
which
surface
water
temperatures
exceed
64.0
°
F
(
17.8
°
C).

This
numeric
criteria
is
measured
as
the
seven
day
moving
average
of
the
daily
maximum
temperatures
(
OAR
341­
41­
006(
54)).
For
point
sources,
the
surface
water
management
plan
will
be
part
of
their
NPDES
permit.
For
nonpoint
sources,
the
surface
water
management
plan
will
be
developed
by
DMAs
which
will
identify
the
appropriate
BMPs
or
measures.

Monitoring
Analysis
of
water
quality
data
indicates
that
the
17.8

C
criteria
would
be
violated
in
most
reaches
in
the
Slough
in
the
spring,
summer
and
fall.
Temperatures
in
Reaches
1A,
1B,
1C,
2A
and
3
indicate
frequent
exceedances
of
the
criteria
during
these
seasons.
The
limited
data
for
Reaches
4
and
5
also
indicate
frequent
exceedances
of
the
temperature
criteria
in
the
spring,
summer
and
fall.
Temperatures
in
the
winter
in
the
Slough
are
generally
below
the
criteria.
(
CH2MHill,
1995,
Part
2)

Modeling
Instream
temperature
may
be
influenced
by
loads
from
industrial
point
sources,
storm
water,
illicit
discharges,
and
nonpoint
sources
as
well
as
the
hydrology
of
the
Slough.
Loads
from
storm
water
and
illicit
discharges
are
presumed
to
be
insignificant
in
comparison
to
the
effect
of
solar
radiation
on
instream
temperatures.
Most
banks
of
the
Slough
are
built
up
as
levees
and
have
little
vegetation.
Shallow
water
levels
in
the
Slough
exacerbate
the
effect
of
lack
of
shading,
so
solar
radiation
heats
up
the
water
to
levels
exceeding
the
temperature
criterion.
Modeling
has
been
done
to
assess
the
impact
of
additional
shading
via
tree
planting
on
the
Middle
and
Upper
Slough
(
Wells,
1995).
For
the
Middle
and
Upper
Slough,
the
average
amount
of
shaded
water
surface
was
estimated
for
the
month
of
August
(
Biorn­
Hansen,
personal
communication)
using
field
measurements
in
representative
areas
by
a
solar
pathfinder.
The
pathfinder
is
used
to
measure
the
magnitude
of
the
shadow
cast
by
the
treeline
in
a
particular
area.
For
each
location
where
the
pathfinder
was
used,
data
was
also
collected
on
stream
width,
bank
geometry
and
vegetation
density.
Site­
specific
shading
estimates
were
then
generated
based
on
field
measurements
combined
with
information
on
azimuth,
declination
angle,
latitude,
and
time
of
year.
These
estimates
were
then
applied
to
the
rest
of
the
Slough.
The
average
amount
of
shaded
water
surface
was
estimated
to
be
20%.
These
field
estimates
of
shading
correlated
with
estimates
developed
by
Wells
(
Wells,
1995,
memo).
50
In
the
shading
simulations,
approximately
80%
of
the
Upper
Slough
was
assumed
to
be
unshaded
for
existing
conditions
and
50%
was
assumed
to
be
unshaded
for
future
conditions.
The
effect
of
flow
management
alone
on
instream
temperature
was
simulated;
then
the
effect
of
flow
management
and
increased
shading
(
to
50%)
was
simulated.
According
to
the
simulations,
the
Upper
Slough
would
be
in
compliance
with
the
temperature
criteria
if
50%
is
shaded.
Shading
in
upstream
reaches
is
predicted
to
have
little
effect
on
the
temperature
in
the
Lower
Slough,
because
the
temperature
of
the
Lower
Slough
is
most
impacted
by
the
incident
solar
radiation
and
relatively
long
residence
times.
Modeling
indicated
that
additional
shading
in
the
Lower
Slough,
under
current
hydrological
conditions,
would
have
negligible
effect
on
instream
temperature.
This
is
because
of
the
following
conditions:
 
Much
of
the
Lower
Slough
is
bordered
by
levees,
and
the
Army
Corps
of
Engineers
prohibits
the
planting
of
trees
on
levees,
 
The
sections
of
the
Lower
Slough
that
are
not
bordered
by
levees
are
already
reasonably
well­
vegetated,
and
 
The
Lower
Slough
is
generally
so
wide
(
up
to
400
ft)
that
most
of
the
water
surface
is
unshaded
whether
or
not
there
are
trees
along
the
banks,
thus
shade
measurements
made
at
various
locations
along
the
Lower
Slough
yielded
values
ranging
from
0%
to
5%.

Several
refinements
are
being
made
to
the
existing
model
for
the
Columbia
Slough.
Some
of
these
refinements,
such
as
shade
calculation
based
on
vegetation
height,
will
influence
temperature
simulations.
The
model
will
be
used
to
predict
the
influence
that
management
strategies
will
have
on
instream
temperature.
The
results
of
these
analyses
will
form
the
basis
for
a
temperature/
solar
radiation
TMDL.
51
Conversion
Factors
To
convert
from:
to:

kg/
day
or
kg/
yr
lb/
day
or
lb/
yr
divide
by
0.454
1
m3
ft
3
multiply
by
35.3
Equation
to
use
flow
and
concentration
to
calculate
a
mass
load:

(
m3/
sec)
x
(
1000
L/
m3)
x
(
mg/
L)
x
(
1
kg/
106
mg)
x
(
60
sec/
min)
x
(
60
min/
hr)
x
(
24
hr/
day)
=
kg/
day