Fact Sheet for Proposal of Heat Load Effluent Limits in Lower Snake River Hydroelectric Generating Facilities

NPDES Fact Sheet, 2021

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AEPA

Fact Sheet for Proposal of Heat Load Effluent Limits in
Lower Snake River Hydroelectric Generating Facilities

The United States Environmental Protection Agency (EPA) proposes to issue
National Pollutant Discharge Elimination System (NPDES) Permits to discharge pollutants
pursuant to the provisions of the Clean Water Act, 33 USC §1251 et seq to:

Facility

Ice Harbor Lock and Dam, U.S. Army Corps of Engineers
Lower Monumental Lock and Dam, U.S. Army Corps of Engineers
Little Goose Lock and Dam, U.S. Army Corps of Engineers
Lower Granite Lock and Dam, U.S. Army Corps of Engineers

Public Comment Start Date:
Public Comment Expiration Date:

January 15, 2021
February 15, 2021

Permit Number

WA0026816
WA0026808
WA0026786
WA0026794

Technical Contact:

Email:

Phone:

Jenny Wu

Wu.Jennifer@epa.gov
(206)553-6328

1-800-424-4372 ext 6328 (within Alaska, Idaho, Oregon and Washington)

The EPA Proposes to Issue NPDES Permits

The EPA proposes to issue NPDES permits for the facilities referenced above. The draft permits place
conditions on the discharge of pollutants from the hydroelectric generating facilities to waters of the
United States (U.S.). To ensure the protection of water quality and human health, these permits place
limits on the types and amounts of pollutants that can be discharged from the facilities.

This Fact Sheet includes:

• information on public comment, public hearing, and appeal procedures

• technical material supporting the heat load effluent limits in the permits

State Certification

The EPA requested final 401 certification of these permits from the Washington Department of Ecology
(Ecology) on March 18, 2020. On May 7, 2020, Ecology provided final certifications of these permits
under Section 401 of the Clean Water Act. One condition in Ecology's final certifications was a
condition to incorporate the wasteload allocations (WLAs) from the Lower Columbia and Snake Rivers
Temperature Total Maximum Daily Load (Lower Columbia and Snake Rivers temperature TMDL).
These revised draft permits now include the effluent limits that incorporate the WLAs.

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Public Comment

On March 18, 2020 EPA proposed NPDES permits for public comment to authorize the discharges from
the Lower Snake River Hydroelectric Generating Facilities. The public notice closed on May 4, 2020.
The draft permits did not include heat load effluent limits. EPA is proposing changes to the draft permits
to include heat load effluent limits and is seeking public comment on these limits.

On May 18, 2020, EPA issued the Lower Columbia and Snake Rivers temperature TMDL, which
included heat load WLAs for the Lower Snake River hydroelectric generating facilities. From May 20,
2020 to August 20, 2020, EPA provided the public an opportunity to comment on the Lower Columbia
and Snake Rivers temperature TMDL. During that time, the U.S. Army Corps of Engineers submitted
new information and analysis and proposed revisions to the heat load WLAs.

EPA is seeking comment on heat load effluent limits based on both the May 2020 WLAs and USACE-
proposed WLAs alternatives. EPA is not seeking comment on other effluent limits or provisions in these
permits. EPA will consider all comments received in the public comment period from March 18, 2020 to
May 4, 2020 and this comment period prior to issuing final permits.

Persons wishing to comment on, or request a Public Hearing for, the draft permits for these facilities
may do so in writing by the expiration date of the Public Comment period. A request for a Public
Hearing must state the nature of the issues to be raised as well as the requester's name, address and
telephone number. All comments and requests for Public Hearings must be in writing and should be
submitted to EPA as described in the Public Comments Section of the attached Public Notice.

Comments must include the commenter's name, address, telephone number, permit name, and permit
number. Comments must include a concise statement of the basis and any relevant facts the commenter
believes EPA should consider in making its decision regarding the conditions and limitations in the final
permit.

After the comment period closes, and all comments have been considered, EPA will review and address
all submitted comments. EPA's Director for the Water Division will then make a final decision
regarding permit issuance. If no substantive comments are received, the tentative conditions in the draft
permits will become final, and the permits will become effective upon issuance. If substantive comments
are received, EPA will address the comments and issue the permit. The permit will become effective no
less than 30 days after the issuance date, unless an appeal is submitted to the Environmental Appeals
Board within 30 days pursuant to 40 CFR 124.19.

Documents are Available for Review

The draft permits, fact sheet, and other information can be found by visiting the Region 10 NPDES
website at: 'http://EPA.gov/rlOearth/waterpermits.htm' and at https://www.epa.gov/npdes-
permits/proposed-discharge-permits-federal-hydroelectric-proiects-lower-snake-river. Because of the
COVID-19 virus and limited building access, EPA cannot make hard copies available for viewing
at EPA offices.

For technical questions regarding the permits or fact sheet, contact Jenny Wu at the phone number or
email listed above.

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Table of Contents

I.	GENERAL AND FACILITY-SPECIFIC INFORMATION	6

II.	IMPAIRED WATERS/TMDLS	6

A.	Proposed Heat Load Effluent Limits from the Lower Columbia and Snake Rivers Temperature TMDL,
May 18, 2020	6

B.	Proposed Heat Load Effluent Limits from information received during public comment	7

III.	EFFLUENT LIMITATIONS AND MONITORING	9

Tables

Table 1. Proposed Heat Load Effluent Limits from Columbia and Snake Rivers Temperature TMDL... 7
Table 2. Proposed Revised Heat Load Effluent Limits from USACE	7

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DEFINITIONS

Administrator means the Administrator of the United States Environmental Protection Agency, or an
authorized representative [40 CFR 122.2],

Average monthly limits means the highest allowable average of "daily discharges" over a calendar
month, calculated as the sum of all "daily discharges" measured during a calendar month divided by the
number of "daily discharges" measured during that month. It may also be referred to as the "monthly
average limits"[40 CFR 122.2],

CFR means the Code of Federal Regulations, which is the official annual compilation of all regulations
and rules promulgated during the previous year by the agencies of the United States government,
combined with all the previously issued regulations and rules of those agencies that are still in effect.

CWA means the Clean Water Act in the United States Code (USC) (formerly referred to as the Federal
Water Pollution Control Act or Federal Water Pollution Control Act Amendments of 1972) Public Law
92-500, as amended by Public Law 95-217, Public Law 95-576, Public Law 96-483, and Public Law 97-
117, 33 USC 1251 etseq. [40 CFR 122.2],

The Director means the Regional Administrator of the EPA Region 10, or the Director of the Water
Division, the Washington Department of Ecology, or an authorized representative thereof.

Discharge when used without qualification means the "discharge of a pollutant."

Discharge Monitoring Report (DMR) means the EPA uniform national form, including any subsequent
additions, revisions, or modifications for the reporting of self-monitoring results by permittees [40 CFR
122.2],

Discharge of a pollutant means any addition of any "pollutant" or combination of pollutants to "waters
of the United States" from any "point source," or any addition of any pollutant or combination of
pollutants to the waters of the "contiguous zone" or the ocean from any point source other than a vessel
or other floating craft which is being used as a means of transportation. This definition includes
additions of pollutants into waters of the United States from: surface runoff which is collected or
channeled by man; discharges through pipes, sewers, or other conveyances owned by a State,
municipality, or other person which do not lead to a treatment works; and discharges through pipes,
sewers, or other conveyances, leading into privately owned treatment works. This term does not include
an addition of pollutants by any "indirect discharger" [40 CFR 122.2],

Draft permit means a document prepared under 40 CFR 124.6 indicating the Director's tentative
decision to issue or deny, modify, revoke and reissue, terminate, or reissue a "permit" [40 CFR 122.2],

Effluent limitation means any restriction imposed by the Director on quantities, discharge rates, and
concentrations of "pollutants" which are "discharged" from "point sources" into "waters of the United
States," the waters of the "contiguous zone," or the ocean [40 CFR 122.2],

Facility means any NPDES point source or any other facility or activity (including land or
appurtenances thereto) that is subject to regulation under the NPDES program.

Influent means the water from upstream that enters the facility.

Monthly Average Limit means the average of "daily discharges" over a monitoring month, calculated as
the sum of all "daily discharges" measured during a monitoring month divided by the number of "daily
discharges" measured during that month [40 CFR 122.2],

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National Pollutant Discharge Elimination System (NPDES) means the national program for issuing,
modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and
enforcing pretreatment requirements, under sections 307, 402, 318, and 405 of CWA [40 CFR 122.2],

Pollutant means dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage,
sewage sludge, munitions, chemical wastes, biological materials, radioactive materials [except those
regulated under the Atomic Energy Act of 1954, as amended (42 USC 2011 et seq.)], heat, wrecked or
discarded equipment, rock, sand, cellar dirt and industrial, municipal, and agricultural waste discharged
into water [40 CFR 122.2],

Total Maximum Daily Load (TMDL) means the sum of the individual wasteload allocations (WLAs) for
point sources, load allocations (LAs) for non-point sources, and natural background when allocating
pollutant loading to a particular waterbody. The TMDL establishes loads at levels that meet applicable
water quality standards.

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I. General and Facility-Specific Information

This fact sheet provides information on the draft National Pollutant Discharge Elimination System
(NPDES) permits for four hydroelectric projects: Ice Harbor Lock and Dam, Lower Monumental
Lock and Dam, Little Goose Lock and Dam, and Lower Granite Lock and Dam.

The fact sheet dated March 18, 2020 provides general information on the facilities, information on
the receiving water, applicable water quality standards, and information on permit history, tribal
consultation, geographic area, facility operations and types of discharges, pollutants associated with
facilities, treatment, description of outfalls, compliance history, receiving water, and proposed final
effluent limits and permit conditions.

The March 2020 draft permits did not include heat load effluent limits. EPA has revised the draft
permits to include heat load effluent limits. The following sections in this fact sheet provide the basis
for the proposed heat load effluent limits for which EPA is seeking public comment.

II. Impaired Waters/TMDLs

Section 303(d) of the CWA requires states to identify specific water bodies where water quality
standards are not expected to be met after implementation of technology-based effluent limitations
by point sources. For all 303(d)-listed water bodies and pollutants, states must develop and adopt
total maximum daily loads (TMDLs) that will specify wasteload allocations (WLAs) for point
sources and load allocations (LAs) for non-point sources, as appropriate. WLAs for point sources are
implemented through limitations incorporated into NPDES permits that are consistent with the
assumptions of the WLAs in the TMDL (40 CFR 122.44(d)(l)(vii)(B)).

The fact sheet dated March 18, 2020 describes impairments from various toxics, total dissolved
gases, and temperature in the Lower Snake River. This fact sheet elaborates further on temperature
impairments.

A. Proposed Heat Load Effluent Limits from the Lower Columbia and Snake Rivers
Temperature TMDL, May 18, 2020

The Snake River is listed as impaired for temperature on Ecology's CWA Section 303(d) list. On
May 18, 2020, EPA issued a TMDL for temperature in the Snake River. The Lower Columbia and
Snake Rivers temperature TMDL determined that if all point sources discharged at their current heat
load (design flow and maximum temperature), the TMDL allocation for the cumulative impact of all
point sources would be attained. The TMDL established facility-wide heat load WLAs for all point
sources, including for the four Lower Snake River federal dams. The draft permits propose facility-
wide heat load limits identical to the WLAs in Table 6-14 of the TMDL as a monthly average. Page
53 of the TMDL states that a monthly average is an appropriate timeframe for heat load limits
because of TMDL modeling assumptions. The draft permits also require continuous temperature
monitoring at a subset of outfalls discharging cooling water.

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Table 1 includes proposed heat load effluent limits from the Columbia and Snake Rivers temperature
TMDL.

Table 1. Proposed Heat Load Effluent Limits from Columbia and Snake Rivers Temperature
TMDL

Facility

Facility-wide heat load effluent limit
(kcals/day)

Ice Harbor Lock and Dam

3.22E+09

Lower Monumental Lock and Dam

1.80E+09

Little Goose Lock and Dam

2.94E+09

Lower Granite Lock and Dam

2.21E+09

The permittee must calculate the sum of heat loads from all outfalls by multiplying the flow and
temperature from each outfall on a monthly average basis and report these on DMRs. The permittee
shall use the following equation to calculate the facility-wide monthly average heat load:

Facility-wide monthly average heat load (kcals/day) = Xoutfaiis [(monthly average temperature
(°C))0utfaii x (monthly average flow (MGD))0Utfaii x 3.78E+06 kcals/day/(°C x MGD)]

The permittee may also conduct representative sampling as outlined in the permit to calculate
facility-wide heat loads. In addition, the permit requires continuous monitoring for any discharges
with cooling water and monthly monitoring where a similar discharge already has continuous
monitoring.

B. Proposed Heat Load Effluent Limits from information received during public comment

After EPA issued the Lower Columbia and Snake Rivers Temperature TMDL, EPA accepted public
comments on the final TMDL from May 21, 2020 to August 20, 2020. During the TMDL public
comment period, USACE requested revised WLAs based on new information and analysis for
facility heat discharges in the summer. The primary basis for the request was that the maximum
temperatures used in the May 18, 2020 temperature TMDL were typically based on one temperature
data point at each outfall, which was not collected in August, the time period with the highest
temperatures. The USACE estimated maximum August temperatures by analyzing the amount that
facility operations would raise influent temperatures in their discharges based on turbine efficiencies
and measured data, and applying these increases to measured August influent temperatures. The
resulting temperatures were then multiplied by the design flow of the outfall to calculate a heat load
for each outfall. The heat loads from each outfall were added together to determine the revised,
facility-wide heat load. The USACE proposed these revised facility-wide heat loads, which reflect
the design flows and maximum temperatures, as WLAs to be applied in a revised TMDL and
subsequently in the NPDES permits. Table 2 includes the proposed heat load effluent limits from the
USACE from the TMDL public comment period.

Table 2. Proposed Revised Heat Load Effluent Limits from USACE

Facility

Facility-wide heat load effluent limit
(kcals/day)

Ice Harbor Lock and Dam

3.53E+09

Lower Monumental Lock and Dam

2.21E+09

Little Goose Lock and Dam

3.24E+09

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Lower Granite Lock and Dam	2.25E+09

The permittee must calculate the sum of heat loads from all outfalls by multiplying the flow and
temperature from each outfall on a monthly average basis and report these on DMRs. The
permittee shall use the following equation to calculate the facility-wide monthly average heat
load:

Facility-wide monthly average heat load (kcals/day) = Xoutfaiis [(monthly average temperature
(°C))outfaii x (monthly average flow (MGD))0Utfaii x 3.78E+06 kcals/day/(°C x MGD)]

The permittee may also conduct representative sampling as outlined in the permit to calculate
facility-wide heat loads. In addition, the permit requires continuous monitoring for any
discharges with cooling water and monthly monitoring where a similar discharge already has
continuous monitoring.

EPA is in the process of reviewing the USACE information supporting revised WLAs as part of
the TMDL process. If EPA issues a revised temperature TMDL for the Lower Columbia and
Snake Rivers, and these WLAs are included in the revised temperature TMDL prior to the final
issuance of these permits, the permits will include the heat load effluent limits in Table 2. EPA is
accepting comment on the effluent limits based upon the current final TMDL as well as the
alternative effluent limits based on the revised WLAs submitted by the USACE during the
TMDL public comment period.

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III. Effluent Limitations and Monitoring

The tables below show the proposed effluent limits for each facility. The proposed draft heat load
limits and conditions are shown in highlighted text and excerpted from the proposed permits.

The following is excerpted from pages 9-11 in the Ice Harbor Lock and Dam draft NPDES permit.

Table 3. Effluent Limitations and Monitoring Requirements for Outfalls 005, 006, 007, 008, 009, 010,
011, 012, 013, 016, 017, 018, 019, 020, and 021: Main Units Non-Contact Cooling Water, Transformer
Non-Contact Cooling Water

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kca Is/day

See Paragraph
I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

See
Paragraph
I.B.10 of this
permit.

Continuous or
1/month 3

Measurement/
Calculation

Visible Oil,
Floating,
Suspended, or
Submerged
Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

1. In the first year of the permit, if there are no exceedances of the pH limit or detection of oil and grease, the required
monitoring frequency forthat pollutant is reduced to 1/month. If there are exceedances/detections in the first year of the
permit, the frequency will remain 1/weekforthe remainder of the permit term.

2. 7-day average daily maximum. This is a rolling 7-day average calculated by taking the average of the daily maximum
temperatures. The 7-day average daily maximum for any individual day is calculated by averaging that day's daily
maximum temperature with the daily maximum temperatures of the three days prior and the three days after that date.

3. See Paragraphs I.B.10 and I.B.11. In the first six months of the effective date of the permit, monthly sampling is
required, Continuous monitoring is required after the first six months of the effective date of the permit.

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Table 4. Effluent Limitations and Monitoring Requirements for Outfall 015: HVAC Chiller

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kcals/day

See Paragraph
I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Total

Suspended
Solids

mg/L

Report

Influent and
Effluent

1/quarter

Grab

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil,
Floating,
Suspended, or
Submerged
Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

1. In the first year of the permit, if there are no exceedances of the pH limit or detection of oil and grease, the required
monitoring frequency for that pollutant is reduced to 1/month. If there are exceedances/detections in the first year of the
permit, the frequency will remain 1/weekforthe remainder of the permit term.

12. The permittee must not exceed a facility-wide monthly average heat load of 3.22E+09 kcals/day.

The facility-wide monthly average heat load is calculated as the summation of the average
monthly heat load for each outfall in accordance with the following equation:

Facility-wide monthly average heat load (kcals/day) = Xoutfaiis [(monthly average temperature
(°C))outfaii x (monthly average flow (MGD))0Utfaii x 3.78E+06 kcals/day/(°C x MGD)]

The heat load for each outfall is calculated as the product of the monthly average temperature
and average monthly flow, times a conversion factor of 3.78E+06 kcals/day/(°C x MGD). All
outfalls identified in Tables 2 and 3 must be included in the summation.

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The following is excerpted from pages 8-12 in the Lower Monumental Lock and Dam draft NPDES
permit.

Table 5. Effluent Limitation and Monitoring Requirements for Outfalls 001 and 002: Drainage Sump,
Jnwatering Sump

Monitoring Requirements

Parameter

Units

Effluent Limitations

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

See Paragraph
I.B.12.

Measurement/
Calculation

Heat Load

kca Is/day

Paragraph

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

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Table 6. Effluent Limitations and Monitoring Requirements for Outfalls 003: Heat Pump

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kca Is/day

See Paragraph
I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Total

Suspended
Solids

mg/L

Report

Influent and
Effluent

1/quarter

Grab

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

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Table 7. Effluent Limitations and Monitoring Requirements for Outfall 004: Emergency Diesel
Generator Cooling Water

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

See

Heat Load

kca Is/day

See Paragraph
I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

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Table 8. Effluent Limitations and Monitoring Requirements for Outfalls 005, 006, 007, 008, 009, 010,
011a, and 01 lb: Main Units Non-Contact Cooling Water, Transformer Non-Contact Cooling Water

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kcals/day

See Paragraph I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2, daily
maximum, and daily
average.

See
Paragraph
I.B.10 of
this permit.

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

1. In the first year of the permit, if there are no exceedances of the pH limit or detection of oil and grease, the
required monitoring frequency for that pollutant is reduced to 1/month. If there are exceedances/detections in the
first year of the permit, the frequency will remain 1/week for the remainder of the permit term.

2. 7-day average daily maximum. This is a rolling 7-day average calculated by taking the average of the daily
maximum temperatures. The 7-day average daily maximum for any individual day is calculated by averaging that
day's daily maximum temperature with the daily maximum temperatures of the three days prior and the three days
after that date.

12. The permittee must not exceed a facility-wide monthly average heat load of 1.80E+09 kcals/day.

The facility-wide monthly average heat load is calculated as the summation of the average monthly
heat load for each outfall in accordance with the following equation:

Facility-wide monthly average heat load (kcals/day) = Xoutfaiis [(monthly average temperature
(°C))outfaii x (monthly average flow (MGD))0Utfaii x 3.78E+06 kcals/day/(°C x MGD)]

The heat load for each outfall is calculated as the product of the monthly average temperature and
average monthly flow, times a conversion factor of 3.78E+06 kcals/day/(°C x MGD). All outfalls
identified in Tables 1, 2, 3 and 4 must be included in the summation.

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The following is excerpted from pages 8-12 in the Little Goose Lock and Dam draft NPDES permit.

Table 9. Effluent Limitations and Monitoring Requirements for Outfalls 001, 002, 011, and 012:

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kca Is/day

See Paragraph I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2, daily
maximum, and daily
average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

1. In the first year of the permit, if there are no exceedances of the pH limit or detection of oil and grease, the required
monitoring frequency for that pollutant is reduced to 1/month. If there are exceedances/detections in the first year of the
permit, the frequency will remain 1/weekforthe remainder of the permit term.

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NPDES Fact Sheet, 2021

US ACE Lower Snake River Hydroelectric Generating Permits

Page 16 of 19

Table 10. Effluent Limitations and Monitoring Requirements for Outfalls 003, 004, 005, 006, 007, 008,
009, 010, and 014: Heat Pump Water, Emergency Diesel Generator Cooling Water, Main Units Non-
Contact Cooling Water, and Visitors Center AJC Drain

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kca Is/day

See Paragraph
I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

See
Paragraph
I.B.10 of this
permit.

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

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NPDES Fact Sheet, 2021

US ACE Lower Snake River Hydroelectric Generating Permits

Page 17 of 19

Table 11. Effluent Limitation and Monitoring Requirements for Outfall 015: Navigation Lock Drainage
Sump

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kcals/day

See Paragraph I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Chemical
oxygen demand

mg/L

Report

Influent and
effluent

1/quarterly

Grab

Temperature

°C

Report 7DADM2, daily
maximum, and daily
average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

3. See Paragraphs I.B.10 and I.B.11. In the first six months ofthe effective date of the permit, monthly sampling is
required, Continuous monitoring is required after the first six months ofthe effective date ofthe permit.

12. The permittee must not exceed a facility-wide monthly average heat load of 2.94E+09 kcals/day.
The facility-wide monthly average heat load is calculated as the summation of the average
monthly heat load for each outfall in accordance with the following equation:

Facility-wide monthly average heat load (kcals/day) = Xoutfaiis [(monthly average temperature
(°C))0utfaii x (monthly average flow (MGD))0utfaii x 3.78E+06 kcals/day/(°C x MGD)]

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NPDES Fact Sheet, 2021

US ACE Lower Snake River Hydroelectric Generating Permits

Page 18 of 19

The following is excerpted from pages 8-11 in the Lower Granite Lock and Dam draft NPDES permit.

Table 12. Effluent Limitations and Monitoring Requirements for Outfalls 001 and 002: Drainage Sump,
Jnwatering Sump

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/mo nth1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/mo nth1

Grab

Heat Load

kca Is/day

See Paragraph I.B.12.

See
Paragraph
I.B.10.

See Paragraph
I.B.12.

Measurement/
Calculation

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

Report 7DADM2, daily
maximum, and daily
average.

Effluent

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

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NPDES Fact Sheet, 2021

US ACE Lower Snake River Hydroelectric Generating Permits

Page 19 of 19

Table 13. Effluent Limitations and Monitoring Requirements for Outfalls 003, 003a, 004, 005, 006, 007,
008, and 009: Main Units Non-Contact Cooling Water, Emergency Diesel Generator Non-Contact
Cooling, Heat Pump Cooling Water

Parameter

Units

Effluent Limitations

Monitoring Requirements

Sample
Location

Sample
Frequency

Sample Type

Parameters With Effluent Limits

std units

Between 6.5 - 8.5

Effluent

1/week or
1/month1

Grab

Oil and grease

mg/L

5 (daily maximum)

Effluent

1/week or
1/month1

Grab

See

Heat Load

kcals/day

See Paragraph
I.B.12.

Paragraph

See Paragraph
I.B.12.

Measurement/
Calculation

I.B.10.

Report Parameters

Flow

mgd

Report

Effluent

1/month

Measurement

Temperature

°C

Report 7DADM2,
daily maximum, and
daily average.

See
Paragraph
1 .B.10 of this
permit.

Continuous or
1/month3

Measurement/
Calculation

Visible Oil

Sheen,

Floating,

Suspended, or

Submerged

Matter

See Paragraph I.B.4 of this permit.

Visual
Observation

Notes

12. The permittee must not exceed a facility-wide monthly average heat load of 2.21E+09
kcals/day.

The facility-wide monthly average heat load is calculated as the summation of the average
monthly heat load for each outfall in accordance with the following equation:

Facility-wide monthly average heat load (kcals/day) = Xoutfaiis [(monthly average temperature
(°C))outfaii x (monthly average flow (MGD))0utfaii x 3.78E+06 kcals/day/(°C x MGD)]

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