ML25059A131

NRR E-mail Capture - (External_Sender) Energy Northwest Columbia Generating Station 2024 Biological Monitoring Report

ML25059A131
Person / Time
Site:	Columbia  (NPF-21)
Issue date:	02/27/2025
From:	Quinones A Energy Northwest Environmental Services Laboratory
To:	Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
Download: ML25059A131 (114)

Text

From:

Quinones, Adrian B. <abquinones@energy-northwest.com>

Sent:

Thursday, February 27, 2025 8:14 PM To:

ritchie.graves@noaa.gov Cc:

Briana Arlene; EndangeredSpecies Resource; Ramos, Mary Joy.; Nguyen, Elisa L.

Subject:

[External_Sender] Energy Northwest Columbia Generating Station 2024 Biological Monitoring Report Attachments:

GO2-25-037 Energy Northwest Columbia Generating Station 2024 Biological Monitoring Report.pdf Mr. Graves, Please find attached the 2024 Biological Monitoring Report for Columbia Generating Station, submitted pursuant to Condition 2.9.4(4)(a) of the Endangered Species Act 7(a)(2) Biological Opinion and copied to the Nuclear Regulatory Commission (NRC). This letter is being provided as an electronic transmittal only.

Thank you, Adrian Quinones l Environmental Specialist Environmental and Regulatory Programs 509-377-8755 labquinones@energy-northwest.com<mailto:abquinones@energy-northwest.com>

[cid:9d1c070d-cbe9-4ed8-8222-2f8f18551874]

Hearing Identifier:

NRR_DRMA Email Number:

2733 Mail Envelope Properties (DM8PR09MB69655FCA3C3A602EF3DA03C0F7CD2)

Subject:

[External_Sender] Energy Northwest Columbia Generating Station 2024 Biological Monitoring Report Sent Date:

2/27/2025 8:14:15 PM Received Date:

2/27/2025 8:14:47 PM From:

Quinones, Adrian B.

Created By:

abquinones@energy-northwest.com Recipients:

"Briana Arlene" <briana.arlene@nrc.gov>

Tracking Status: None "EndangeredSpecies Resource" <EndangeredSpecies.Resource@nrc.gov>

Tracking Status: None "Ramos, Mary Joy." <mjoyramos@energy-northwest.com>

Tracking Status: None "Nguyen, Elisa L." <elnguyen@energy-northwest.com>

Tracking Status: None "ritchie.graves@noaa.gov" <ritchie.graves@noaa.gov>

Tracking Status: None Post Office:

DM8PR09MB6965.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 575 2/27/2025 8:14:47 PM GO2-25-037 Energy Northwest Columbia Generating Station 2024 Biological Monitoring Report.pdf 6232500 Options Priority:

Normal Return Notification:

No Reply Requested:

No Sensitivity:

Normal Expiration Date:

GO2-25-037 Attachment 1: Biological Monitoring Report Summary 2024 Post Season Fish Collection Report The purpose of this report is to document fish collection activities on the part of Energy Northwest (ENW) during the 2024 calendar year and to verify that the activities were following the Endangered Species Act section 7(a)(2) Biological Opinion for the Columbia Generating Station (NMFS No: NWR/2011/05286) issued 3/10/17. Also included is a discussion on changes in CGS operations during the 2024 calendar year that had the potential to affect CGS effluent discharges to the Columbia River.

Fish Collection Columbia Generating Station (CGS) is required to collect and analyze fish samples from locations near the CGS effluent discharge in the Columbia River and from a control location, typically the Snake River. The samples are analyzed for radioactive content with the purpose of determining what impact, if any, CGS operation may have on Columbia River fish. The requirements specify collection of one anadromous and two resident fish species from both locations. The fish collection activities are to be performed in accordance with the Endangered Species Act section 7(a)(2) Biological Opinion for CGS.

Resident Species Collection Columbia River In 2024, three resident fish species were collected from the Columbia River: three smallmouth bass, three walleyes, and one perch. On June 20, 2024, Energy Northwest (ENW) personnel collected three smallmouth bass and one perch from the Columbia River, at GPS coordinates 46°11'24.0"N, 119°1'51.6"W. The water temperature at this location was 3.7 degrees Celsius.

Additionally, three walleyes were caught further upstream, at GPS coordinates 46°11'27.6"N, 119°2'20.4"W, with a water temperature of 3.6 degrees Celsius. All fish were caught using hook and line techniques targeting bass, walleye, and perch.

These fishing techniques complied with the Washington Department of Fish and Wildlife (WDFW) freshwater fishing rules for the resident species of interest. A professional fishing guide, operating a fully licensed boat, was utilized to catch the fish. The Offsite Dose Calculation Manual (ODCM) and Energy Facility Site Evaluation Council (EFSEC) requirements for resident fish were not met for 2024. It was identified that the GPS coordinates where the resident fish were collected were not within the vicinity of the plant discharge area. To prevent recurrence, an assignment was created to review fish collection data to ensure the sampling locations, types of fish, and number of fish are sufficient.

Snake River In 2024, two resident fish species were collected from the Snake River: two smallmouth bass and two walleyes.

On June 20, 2024, Energy Northwest (ENW) personnel collected two smallmouth bass and two walleyes from the Snake River, just north of Sacajawea State Park. GPS coordinates were recorded as 46°12'18.0"N, 119°1'55.2"W and 46°12'03.6"N, 119°1'48"W. The water temperature at this location was 3.6 degrees Celsius. These fish were caught using hook and line techniques targeting bass and walleye.

The fishing techniques used complied with the Washington Department of Fish and Wildlife (WDFW) freshwater fishing rules for the resident species of interest. A professional fishing guide, operating a fully licensed boat, was utilized to catch the fish.

The ODCM and EFSEC requirements for resident fish from a control location for 2024 were successfully met.

Anadromous Species Collection The anadromous species collected from the Snake and Columbia Rivers was Chinook salmon. Authorization to obtain the fish from local hatcheries was provided by the State of Washington Dept. of Fish and Wildlife in a letter dated 8/9/2024.

One Chinook Salmon from Columbia River Ringold Springs Hatchery was collected on 10/9/2024. The GPS coordinates 46°30'49.3"N, 119°15'32.9"W and the water temperature was 17.0 degrees Celsius. The salmon was caught by the hatchery personnel using a net.

A Chinook Salmon was provided by Snake River Lyons Ferry Hatchery on 10/23/2024, GPS coordinates 46° 35.85 N, 118° 13.45 W and the river temperature was 17.5 degrees Celsius. The salmon was caught by the hatchery personnel using a net.

Fish Collection Summary Reasonable and prudent measures were utilized to minimize the impact of biological monitoring activities during 2024. Fish collection was performed using hook and line techniques that targeted the species of interest; electroshock fishing was not performed.

No capture or handling of Upper Columbia River (UCR) spring-run Chinook salmon occurred during the year.

Summary of Changes to CGS Aqueous Effluent Discharges During the 2024 calendar year, the National Pollutant Discharge Elimination System (NPDES) effluent monitoring, as reported in the monthly discharge monitoring reports, indicated that all parameters were within permit specifications. Three noncompliance events were reported per NPDES Permit Special Condition S3.F and are detailed in the attached 2024 5-day Discharge Noncompliance Reports.

Please submit this report at the end of the permit period:

Project Start Date 6/20/2024 EFSEC WDFW Permittee Name Mary Joy Ramos ATTN: AMY MOON ATTN: LICENSING DIVISION Agency/Institution EnergyNorthwest PO Box 43172 EMAIL: Peggy.Miller@dfw.wa.gov Email Address Elnguyen@energy-northwest.com Olympia, WA 98504-3172 Todd.Miller@dfw.wa.gov Permit No.

EFSECResolution347 EMAIL: Amy.Moon@efsec.wa.gov PHONE: 360-902-2464, option 4 PHONE: 360-664-1362

• Disposition codes - please select carefully; more than one code may be used

1. Survey/observation/non-handling "take"

8. Release at capture site, dead

2. Captive for research, live

9. Tag/mark and release

3. Euthanize/mortality, hold for analysis

10. Move and release, live

4. Euthanize/mortality, waste disposal

11. Sub-lethal tissue collection, release at site

5. Display, live

12. Lethal tissue collection

6. Display, dead

13. Other (describe)

7. Release at capture site, live Life Stage (for salmonids only) = A (adult), J (Juvenile), F (Fry), E (Egg)

Origin (for salmonids only) = W (wild), H (hatchery)

Methods/Actions = collection method GPS Coordinates should be in WGS84 decimal degrees format For tissue sampling, please state the type of tissue collected Date of Collection Species - Common and Scientific name Life Stage Origin Number Encountered Water Name Specific Location (e.g.,

reach location, reservoir name, etc.)

GPS Coordinates (WGS84 decimal degrees format)

Disposition Code(s)*

Methods/Actions Genetic Sampling Y/N Comments 6/20/2024 Walleye (Sander vitreus)

W 1

Columbia River Columbia River downstream from CGS Discharge 46°11'27.6"N 119°02'20.4"W 12 Hook and line fishing N

Tissue collected -

fillet 6/20/2024 Walleye (Sander vitreus)

W 2

Columbia River Columbia River downstream from CGS Discharge 46°11'27.6"N 119°02'20.4"W 12 Hook and line fishing N

Tissue collected -

fillet 6/20/2024 Perch (Perca)

W 1

Columbia River Columbia River downstream from CGS Discharge 46°11'24.0"N 119°01'51.6"W 12 Hook and line fishing N

Tissue collected -

fillet 6/20/2024 Smallmouth Bass (Micropterus dolomieu)

W 3

Columbia River Columbia River downstream from CGS Discharge 46°11'24.0"N 119°01'51.6"W 12 Hook and line fishing N

Tissue collected -

fillet 6/20/2024 Smallmouth Bass (Micropterus dolomieu)

W 2

Snake River Between Ice Harbor Dam and Strawberry Island 46°12'03.6"N 119°01'48.0"W 12 Hook and line fishing N

Tissue collected -

fillet 6/20/2024 Walleye (Sander vitreus)

W 2

Snake River Between Ice Harbor Dam and Strawberry Island 46°12'18.0"N 119°01'58.8"W 12 Hook and line fishing N

Tissue collected -

fillet 10/9/2024 Chinook (Oncorhynchus tshawytscha)

J H

1 Columbia River Ringold Hatchery 46°30'49.3"N 119°15'32.9"W 12 Net - collected by Hatchery Personnel N

Tissue collected -

fillet 10/23/2024 Chinook (Oncorhynchus tshawytscha)

A H

1 Snake River Lyons Ferry Hatchery 46° 35.85 N 118° 13.45 W 12 Net - collected by Hatchery Personnel N

Tissue collected -

fillet Please provide the WRIA (and stream name) or Marine Area and also provide the GPS coordinates. If sampling more than one location, report data by location.

RESOLUTION 347 ANNUAL REPORT FORM ENERGY FACILITY SITE EVALUATION and WASHINGTON DEPARTMENT OF FISH & WILDLIFE

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-024 DIC: 1316.20 DATE:

February 15, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Ashley Mowery, Water Treatment Op/Env. Scientist, Environmental Services (350)

SUBJECT:

Columbia Generating Station January 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for January 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, January 2024 AJM

Columbia Generating Station Page 2 of 2 June 25, 2024 Columbia Generating Station January 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 A Mowery (via email)

Regulatory (via email)

K Byers (via email)

Document Control (via APW)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Ashley Mowery, Water Treatment Op/Env. Scientist, Environmental Services Reviewed by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Devon Van Alyne, Laboratory Services Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 3 Monitoring Period:01/01/2024 - 01/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-M 1/1/24 3.1 8.0 8.1 0.01 23.3 1-T 1/2/24 3.1 8.0 8.0 0.01 24.9 1-W 1/3/24 3.1 8.0 8.1 0.01 23.8 1.07*

13.2*

1-Th 1/4/24 3.1 8.0 8.1 0.01 24.0 1-F 1/5/24 3.2 8.0 8.0 0.01 24.0 1-Sa 1/6/24 3.2 8.0 8.1 0.01 24.2 2-Su 1/7/24 3.2 8.0 8.1 0.01 22.7 2-M 1/8/24 3.2 8.0 8.0 0.01 22.1 2-T 1/9/24 3.2 7.9 8.1 0.01 27.3 2-W 1/10/24 3.2 8.0 8.1 0.01 24.3 2-Th 1/11/24 2.6 8.0 8.1 0.01 23.8 2-F 1/12/24 0.3 7.9 8.4 0

0.00

<0.1*

0.0 2-Sa 1/13/24 2.6 8.0 8.4 0.01 27.4 3-Su 1/14/24 2.6 8.0 8.0 0.01 26.4 3-M 1/15/24 2.7 7.9 8.0 0.05 23.4 3-T 1/16/24 2.8 7.9 8.0 0.01 23.9 3-W 1/17/24 3.0 7.9 8.0 0.01 24.2 3-Th 1/18/24 2.9 7.9 8.0 0.01 26.1 3-F 1/19/24 2.6 8.0 8.1 0.01 26.2 3-Sa 1/20/24 2.6 8.0 8.1 0.01 24.5 4-Su 1/21/24 2.6 8.0 8.1 0.01 24.5 4-M 1/22/24 2.5 8.0 8.1 0.01 21.8 4-T 1/23/24 2.5 8.0 8.1 0.01 22.0 4-W 1/24/24 1.0 8.0 8.1 0.01 21.6 4-Th 1/25/24 0.1 7.8 8.3 0

0.03

<0.1*

0.0 4-F 1/26/24 1.1 8.1 8.4 0

0.03

<0.1*

22.3 4-Sa 1/27/24 3.1 8.2 8.2 0.01 22.4 5-Su 1/28/24 3.1 8.1 8.2 0.01 22.1 5-M 1/29/24 3.1 8.1 8.7 0.01 23.1 5-T 1/30/24 3.1 8.1 8.2 0.01 23.6 5-W 1/31/24 3.1 8.1 8.5 0.01 23.7 Daily Minimum 7.8 18.0

>= 6.5 (RO)

Report Only Average Monthly 2.6 1.07 13.2 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3.2 8.7 0.05 27.4 1.07 13.2

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 3 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 1/12/2024 Bl<0.1 Grab sample verification of TRH <0.1 prior to resuming blowdown.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 1/25/2024 Bl<0.1 Grab sample verification of TRH <0.1 prior to resuming blowdown.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 1/26/2024 Bl<0.1 Grab sample verification of TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 1/3/2024 1.07 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 1/2/24-1/3/24 CWB Zinc Total Micrograms/L (ug/L) 1/3/2024 13.2 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 1/2/24-1/3/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 3 Monitoring Period:01/01/2024 - 01/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-M 1/1/24 20.6 1-T 1/2/24 20.5 1-W 1/3/24 20.6 1-Th 1/4/24 20.7 1-F 1/5/24 21.4 1-Sa 1/6/24 21.8 2-Su 1/7/24 21.1 2-M 1/8/24 20.1 2-T 1/9/24 22.3 2-W 1/10/24 21.2 2-Th 1/11/24 20.2 2-F 1/12/24 16.1 2-Sa 1/13/24 18.2 3-Su 1/14/24 18.5 3-M 1/15/24 18.2 3-T 1/16/24 18.5 3-W 1/17/24 18.9 3-Th 1/18/24 19.1 3-F 1/19/24 19.7 3-Sa 1/20/24 19.5 4-Su 1/21/24 20.0 4-M 1/22/24 19.9 4-T 1/23/24 19.9 4-W 1/24/24 18.5 4-Th 1/25/24 17.0 4-F 1/26/24 18.3 4-Sa 1/27/24 20.8 5-Su 1/28/24 20.7 5-M 1/29/24 20.6 5-T 1/30/24 20.8 5-W 1/31/24 21.2 Average Monthly 19.8 Report Only Monthly Total 615.1 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 2/15/2024 1:13:08 PM

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1917544 - 2/15/2024 1:13:11 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only c4/mBlWAJmvgmaigoxNAMXj4EqCHZCCbWGxfaa

+COqm5LOzt2JYaI0v33+ubFCEE4mMaVyv06f8rOLuCsdTodmdQzOcFHNXeLnosMOVDROw=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Thursday February 15 2024 Report Received: 2024-02-15 13:13 Page 1 of 1 Pages

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-037 DIC: 1316.20 DATE:

March 13, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station February 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for February 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, February 2024 KRB

Columbia Generating Station Page 2 of 2 March 13, 2024 Columbia Generating Station February 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

T Fitzpatric (via email)

Document Control (via APW)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Tim Fitzpatric, Water Treatment Op/Env. Scientist, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Devon Van Alyne, Laboratory Services Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1921093 - 3/13/2024 1:26:52 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only lcLncEdRnWvDcmIIiJjAYGXx8jxoYcTRDG/hCZnaPt8UO148dg1L0z1v0xGL4L2QQUo9u+u56FxJ0mEDIXuPV

+rCAPY3F4mdHtY4Gf4RhiE=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday March 13 2024 Report Received: 2024-03-13 13:26 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:02/01/2024 - 02/29/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-Th 2/1/24 3.1 8.1 8.2 0.01 24.8 1-F 2/2/24 3.1 8.1 8.2 0.00 24.8 1-Sa 2/3/24 3.1 8.1 8.2 0.01 24.8 2-Su 2/4/24 3.1 8.1 8.2 0.00 25.4 2-M 2/5/24 1.5 8.1 8.3 0

0.01 24.0 2-T 2/6/24 C

C C

C C

<0.1*

C 2-W 2/7/24 0.4 8.3 8.5 0

0.04 21.5 2-Th 2/8/24 2.7 7.9 8.8 0.04 24.5 2-F 2/9/24 2.7 7.9 8.1 0.01 24.2 2-Sa 2/10/24 2.7 7.9 8.1 0.01 21.9 3-Su 2/11/24 2.7 7.9 8.1 0.01 21.7 3-M 2/12/24 2.7 7.8 8.1 0.01 22.4 3-T 2/13/24 2.7 7.7 8.0 0.01 22.3 1.06*

16.6*

3-W 2/14/24 2.7 7.8 8.0 0.01 21.2 3-Th 2/15/24 2.7 7.8 8.0 0.01 21.1 3-F 2/16/24 2.7 7.8 8.0 0.01 21.7 3-Sa 2/17/24 2.7 7.7 8.0 0.01 27.6 4-Su 2/18/24 2.7 7.8 8.0 0.01 22.0 4-M 2/19/24 2.7 7.8 8.0 0.01 23.4 4-T 2/20/24 2.7 7.8 8.0 0.01 24.7 4-W 2/21/24 2.7 7.8 8.0 0.01 25.1 4-Th 2/22/24 2.7 7.8 8.0 0.03 24.8 4-F 2/23/24 2.7 7.8 8.0 0.01 25.4 4-Sa 2/24/24 2.7 7.8 8.0 0.01 25.2 5-Su 2/25/24 2.7 7.8 8.0 0.01 26.9 5-M 2/26/24 2.7 7.7 8.1 0.01 27.0 5-T 2/27/24 2.7 7.7 7.9 0.01 23.9 5-W 2/28/24 2.7 7.7 7.9 0.01 25.1 5-Th 2/29/24 2.7 7.7 8.0 0.02 25.1 Daily Minimum 7.7 18.6

>= 6.5 (RO)

Report Only Average Monthly 2.5 1.06 16.6 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3.1 8.8 0.04 27.6 1.06 16.6

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 2/6/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 2/13/2024 1.06 Result from 24-hour composite collected 2/12/24-2/13/24 CWB Zinc Total Micrograms/L (ug/L) 2/13/2024 16.6 Result from 24-hour composite collected 2/12/24-2/13/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Monitoring Period:02/01/2024 - 02/29/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-Th 2/1/24 21.6 1-F 2/2/24 21.0 1-Sa 2/3/24 20.8 2-Su 2/4/24 19.8 2-M 2/5/24 20.4*

2-T 2/6/24 20.4*

2-W 2/7/24 20.4*

2-Th 2/8/24 21.1 2-F 2/9/24 21.5 2-Sa 2/10/24 21.7 3-Su 2/11/24 21.6 3-M 2/12/24 22.1 3-T 2/13/24 21.8 3-W 2/14/24 21.8 3-Th 2/15/24 20.6 3-F 2/16/24 20.7 3-Sa 2/17/24 21.2 4-Su 2/18/24 21.3 4-M 2/19/24 21.5 4-T 2/20/24 21.8 4-W 2/21/24 21.9 4-Th 2/22/24 21.9 4-F 2/23/24 21.8 4-Sa 2/24/24 22.5 5-Su 2/25/24 22.8 5-M 2/26/24 21.8 5-T 2/27/24 21.4 5-W 2/28/24 23.1 5-Th 2/29/24 22.5 Average Monthly 21.5 Report Only Monthly Total 622.8 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Outfall: Intk - Cooling water intake structure Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment Intk Flow MGD 2/5/2024 20.4 Flow is estimated based on average of 2/4/24 and 2/8/24, due to maintenance outage flow data unavailable 2/5/24-2/7/24.

Intk Flow MGD 2/6/2024 20.4 Flow is estimated based on average of 2/4/24 and 2/8/24, due to maintenance outage flow data unavailable 2/5/24-2/7/24.

Intk Flow MGD 2/7/2024 20.4 Flow is estimated based on average of 2/4/24 and 2/8/24, due to maintenance outage flow data unavailable 2/5/24-2/7/24.

Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 3/13/2024 1:26:48 PM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-054 DIC: 1316.20 DATE:

May 13, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

REVISED Columbia Generating Station March 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the revised NPDES Discharge Monitoring Report (DMR) for March 2024. The DMR was revised due to clarification provided by State of Washington Department of Ecology (Ecology) on permit language regarding the reporting of Total Residual Halogen (TRH). TRH was previously reported as instantaneous daily maximum but based on the clarification it should be reported as the average measurement of the pollutant over the day. The TRH values in this revised DMR have been corrected to average measurement during the calendar day. No values other than TRH were revised.

Included in this DMR is an exceedance of the permitted maximum daily limit for TRH of 0.1 mg/L due to malfunction in the Halogenation/Dehalogenation system. This was identified 3/6/24 at 1635 and notification was made to the Energy Facility Site Evaluation Council (EFSEC) 3/6/24 at 2303. This violation is documented in the DMR submission and included in the certification package is the NRC Form 361 with the event description.

All other monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to Ecology via the online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, March 2024 KRB

Columbia Generating Station Page 2 of 2 June 25, 2024 Columbia Generating Station REVISED March 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

A Mowery (via email)

Document Control (via APW)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Ashley Mowery, Water Treatment Op/Env. Scientist, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Devon Van Alyne, Laboratory Services Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:03/01/2024 - 03/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-F 3/1/24 2.7 7.7 7.9 0.00 23.9 1-Sa 3/2/24 2.7 7.8 8.0 0.00 23.9 2-Su 3/3/24 2.7 7.8 7.9 0.00 23.1 2-M 3/4/24 2.7 7.7 8.0 0.00 25.1 2-T 3/5/24 2.7 7.7 7.9 0.01 25.1

<1.0*

15.2*

2-W 3/6/24 1.9 7.8 8.3 1.06*

23.4 2-Th 3/7/24 0.9 8.2 8.3 0

<0.1*

<0.1*

23.4 2-F 3/8/24 2.8 8.2 8.3 M*

24.4 2-Sa 3/9/24 2.8 8.2 8.4 M*

25.5 3-Su 3/10/24 2.8 8.2 8.4 M*

26.8 3-M 3/11/24 2.8 8.2 8.3 M*

25.8 3-T 3/12/24 1.1 8.2 8.3 M*

26.2 3-W 3/13/24 1.4 7.8 8.3 0.01*

<0.1*

25.7 3-Th 3/14/24 3.0 7.8 8.1 0.01 24.4 3-F 3/15/24 3.0 7.8 8.0 0.01 25.6 3-Sa 3/16/24 3.0 7.8 8.0 0.01 26.8 4-Su 3/17/24 3.0 7.8 8.0 0.00 27.4 4-M 3/18/24 3.0 7.8 8.0 0.00 27.3 4-T 3/19/24 3.0 7.8 8.0 0.00 27.7 4-W 3/20/24 3.0 7.8 8.0 0.00 27.6 4-Th 3/21/24 3.0 7.8 8.0 0.00 26.8 4-F 3/22/24 3.0 7.8 8.0 0.00 26.3 4-Sa 3/23/24 3.0 7.8 8.0 0.00 26.5 5-Su 3/24/24 3.0 7.8 8.0 0.00 26.3 5-M 3/25/24 3.0 7.7 8.0 0.00 27.7 5-T 3/26/24 2.9 7.7 8.0 0.00 28.2 5-W 3/27/24 3.0 7.7 7.9 0.00 28.2 5-Th 3/28/24 1.7 7.8 8.3 0

0.01

<0.1*

26.9 5-F 3/29/24 2.9 7.8 8.0 0.00 25.5 5-Sa 3/30/24 2.8 7.8 8.0 0.00 25.4 6-Su 3/31/24 2.8 7.8 8.0 0.00 25.5 Daily Minimum 7.7 17.7

>= 6.5 (RO)

Report Only Average Monthly 2.6

<1.0 15.2 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3

8.4 1.06*

28.2

<1.0 15.2

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 2

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L)

Daily Maximum 1.06 TRH exceedance of NPDES maximum daily effluent limit due to malfunction in the Halogenation/Dehalogenation system. Maximum daily effluent limit is defined as being the highest allowable daily discharge. Per the NPDES permit Table 2 footnote b, the daily discharge is the average discharge of TRH measured during a calendar day. The average TRH discharge for the noncompliance period of 3/6/24, was 1.06 mg/L. Based on a review of continuous TRH data collected, TRH readings above the 0.1 mg/L maximum daily effluent limit for TRH began on 3/6/24 at approximately 0815 PST and ended on 3/6/24 at approximately 1646 PST (when blowdown to the Columbia River was isolated). Notification made to EFSEC 3/6/24 at 2303.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/6/2024 1.06 TRH exceedance of NPDES maximum daily effluent limit due to malfunction in the Halogenation/Dehalogenation system. Maximum daily effluent limit is defined as being the highest allowable daily discharge. Per the NPDES permit Table 2 footnote b, the daily discharge is the average discharge of TRH measured during a calendar day. The average TRH discharge for the noncompliance period of 3/6/24, was 1.06 mg/L. Based on a review of continuous TRH data collected, TRH readings above the 0.1 mg/L maximum daily effluent limit for TRH began on 3/6/24 at approximately 0815 PST and ended on 3/6/24 at approximately 1646 PST (when blowdown to the Columbia River was isolated). Notification made to EFSEC 3/6/24 at 2303.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/7/2024 Bl<0.1 Continuous halogenation inoperable, operating in batch halogenation mode. Per NPDES permit Table 4 footnote e, batch sampling procedure conducted prior to resuming discharge on 3/7/24. Two grab samples collected, both were <0.1 mg/L CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/8/2024 MlM Continuous halogenation inoperable, operating in batch halogenation mode. No halogenation 3/8/24.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/9/2024 MlM Continuous halogenation inoperable, operating in batch halogenation mode. No halogenation 3/9/24.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/10/2024 MlM Continuous halogenation inoperable, operating in batch halogenation mode. No halogenation 3/10/24.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/11/2024 MlM Continuous halogenation inoperable, operating in batch halogenation mode. No halogenation 3/11/24.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/12/2024 MlM Continuous halogenation inoperable, operating in batch halogenation mode. No halogenation 3/12/24.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/13/2024 0.01 Continuous halogenation inoperable, operating in batch halogenation mode. Blowdown closed 3/12/24 0959 for batch halogenation. Per NPDES permit Table 4 footnote e, batch sampling procedure conducted prior to resuming discharge on 3/13/24. Two grab samples collected, both were <0.1 mg/L CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/7/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to resuming blowdown.

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/13/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to resuming blowdown.

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 3/28/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 3/5/2024 Bl<1.0 Result from 24-hour composite collected 3/4/24-3/5/24 CWB Zinc Total Micrograms/L (ug/L) 3/5/2024 15.2 Result from 24-hour composite collected 3/4/24-3/5/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:03/01/2024 - 03/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-F 3/1/24 22.2 1-Sa 3/2/24 21.9 2-Su 3/3/24 21.9 2-M 3/4/24 22.3 2-T 3/5/24 22.2 2-W 3/6/24 20.3 2-Th 3/7/24 19.8 2-F 3/8/24 21.7 2-Sa 3/9/24 22.3 3-Su 3/10/24 22.9 3-M 3/11/24 17.6 3-T 3/12/24 21.0 3-W 3/13/24 21.5 3-Th 3/14/24 20.1 3-F 3/15/24 23.0 3-Sa 3/16/24 23.4 4-Su 3/17/24 23.6 4-M 3/18/24 23.9 4-T 3/19/24 24.2 4-W 3/20/24 24.4 4-Th 3/21/24 24.1 4-F 3/22/24 23.4 4-Sa 3/23/24 23.2 5-Su 3/24/24 23.1 5-M 3/25/24 23.1 5-T 3/26/24 23.3 5-W 3/27/24 23.1 5-Th 3/28/24 21.6 5-F 3/29/24 23.1 5-Sa 3/30/24 23.2 6-Su 3/31/24 23.7 Average Monthly 22.4 Report Only Monthly Total 695.1 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 2 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 5/15/2024 9:48:05 AM

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1929433 - 5/15/2024 9:48:07 AM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only 8VHD81Nf0J0oF6gFKjMgu6K1aZtDc1WisOIXq578YKExrnfI/EWcVJZdgpBemdOKmYBv6rClgyv79zHXgUuob8U5HSFqo WOADvMUB42SxQU=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday May 15 2024 Report Received: 2024-05-15 09:48 Page 1 of 1 Pages

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-052 DIC: 1316.20 DATE:

May 14, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station April 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for April 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, April 2024 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

A Mowery (via email)

Document Control (via APW)

Columbia Generating Station Page 2 of 2 June 25, 2024 Columbia Generating Station April 2024 NPDES Discharge Monitoring Report I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Ashley Mowery, Water Treatment Op/Env. Scientist, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Reviewed by: Devon Van Alyne, Laboratory Services Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 3 Monitoring Period:04/01/2024 - 04/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-M 4/1/24 2.8 7.7 8.0 0.00 29.6 1-T 4/2/24 2.8 7.5 8.1 0.00 31.8 1.16*

14.3*

1-W 4/3/24 2.8 7.7 7.9 0.00 29.7 1-Th 4/4/24 2.8 7.7 7.9 0.00 26.4 1-F 4/5/24 2.9 7.6 7.8 0.00 25.8 1-Sa 4/6/24 2.9 7.6 7.8 0.00 26.0 2-Su 4/7/24 2.9 7.7 7.8 0.00 26.5 2-M 4/8/24 2.9 7.5 7.9 0.00 29.3 2-T 4/9/24 2.8 7.5 7.8 0.00 30.0 2-W 4/10/24 2.8 7.6 7.8 0.00 30.1 2-Th 4/11/24 2.8 7.6 7.9 0.00 28.8 2-F 4/12/24 2.8 7.6 7.8 0.00 26.4 2-Sa 4/13/24 2.8 7.6 7.8 0.00 27.2 3-Su 4/14/24 2.8 7.6 7.8 0.00 27.7 3-M 4/15/24 2.7 7.6 7.9 0.00 29.6 3-T 4/16/24 2.7 7.7 7.9 0.00 29.5 3-W 4/17/24 2.8 7.7 7.9 0.00 28.2 3-Th 4/18/24 1.8 7.7 7.9 0.00 24.9 3-F 4/19/24 1.2 7.7 7.9 0

0.01

<0.1*

25.2 3-Sa 4/20/24 2.8 7.7 7.9 0.00 25.5 4-Su 4/21/24 2.9 7.7 7.9 0.00 26.6 4-M 4/22/24 3.0 7.7 7.9 0.00 25.7 4-T 4/23/24 3.0 7.7 7.9 0.00 25.4 4-W 4/24/24 3.0 7.6 7.9 0.01 26.3 4-Th 4/25/24 3.2 7.6 7.8 0.00 26.9 4-F 4/26/24 3.0 7.5 8.5 0.00 26.6 4-Sa 4/27/24 3.0 7.7 8.0 0.00 26.3 5-Su 4/28/24 3.0 7.7 7.9 0.00 26.6 5-M 4/29/24 3.0 7.7 8.0 0.00 26.3 5-T 4/30/24 3.0 7.8 8.0 0.01 25.2 Daily Minimum 7.5 21.8

>= 6.5 (RO)

Report Only Average Monthly 2.8 1.16 14.3 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3.2 8.5 0.01 31.8 1.16 14.3

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 3 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 4/19/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 4/2/2024 1.16 Result from 24-hour composite collected 4/1/24-4/2/24 CWB Zinc Total Micrograms/L (ug/L) 4/2/2024 14.3 Result from 24-hour composite collected 4/1/24-4/2/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 3 Monitoring Period:04/01/2024 - 04/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-M 4/1/24 23.7 1-T 4/2/24 24.6 1-W 4/3/24 23.5 1-Th 4/4/24 22.1 1-F 4/5/24 22.5 1-Sa 4/6/24 23.3 2-Su 4/7/24 23.1 2-M 4/8/24 23.1 2-T 4/9/24 24.2 2-W 4/10/24 23.4 2-Th 4/11/24 23.4 2-F 4/12/24 24.0 2-Sa 4/13/24 23.9 3-Su 4/14/24 24.7 3-M 4/15/24 24.1 3-T 4/16/24 23.4 3-W 4/17/24 23.3 3-Th 4/18/24 21.6 3-F 4/19/24 21.3 3-Sa 4/20/24 23.9 4-Su 4/21/24 24.1 4-M 4/22/24 23.4 4-T 4/23/24 23.8 4-W 4/24/24 24.1 4-Th 4/25/24 24.0 4-F 4/26/24 24.3 4-Sa 4/27/24 23.9 5-Su 4/28/24 24.0 5-M 4/29/24 23.4 5-T 4/30/24 23.0 Average Monthly 23.5 Report Only Monthly Total 705.1 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 5/14/2024 8:45:22 PM

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 3 Monitoring Period:04/01/2024 - 04/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-M 4/1/24 2.8 7.7 8.0 0.00 29.6 1-T 4/2/24 2.8 7.5 8.1 0.00 31.8 1.16*

14.3*

1-W 4/3/24 2.8 7.7 7.9 0.00 29.7 1-Th 4/4/24 2.8 7.7 7.9 0.00 26.4 1-F 4/5/24 2.9 7.6 7.8 0.00 25.8 1-Sa 4/6/24 2.9 7.6 7.8 0.00 26.0 2-Su 4/7/24 2.9 7.7 7.8 0.00 26.5 2-M 4/8/24 2.9 7.5 7.9 0.00 29.3 2-T 4/9/24 2.8 7.5 7.8 0.00 30.0 2-W 4/10/24 2.8 7.6 7.8 0.00 30.1 2-Th 4/11/24 2.8 7.6 7.9 0.00 28.8 2-F 4/12/24 2.8 7.6 7.8 0.00 26.4 2-Sa 4/13/24 2.8 7.6 7.8 0.00 27.2 3-Su 4/14/24 2.8 7.6 7.8 0.00 27.7 3-M 4/15/24 2.7 7.6 7.9 0.00 29.6 3-T 4/16/24 2.7 7.7 7.9 0.00 29.5 3-W 4/17/24 2.8 7.7 7.9 0.00 28.2 3-Th 4/18/24 1.8 7.7 7.9 0.00 24.9 3-F 4/19/24 1.2 7.7 7.9 0

0.01

<0.1*

25.2 3-Sa 4/20/24 2.8 7.7 7.9 0.00 25.5 4-Su 4/21/24 2.9 7.7 7.9 0.00 26.6 4-M 4/22/24 3.0 7.7 7.9 0.00 25.7 4-T 4/23/24 3.0 7.7 7.9 0.00 25.4 4-W 4/24/24 3.0 7.6 7.9 0.01 26.3 4-Th 4/25/24 3.2 7.6 7.8 0.00 26.9 4-F 4/26/24 3.0 7.5 8.5 0.00 26.6 4-Sa 4/27/24 3.0 7.7 8.0 0.00 26.3 5-Su 4/28/24 3.0 7.7 7.9 0.00 26.6 5-M 4/29/24 3.0 7.7 8.0 0.00 26.3 5-T 4/30/24 3.0 7.8 8.0 0.01 25.2 Daily Minimum 7.5 21.8

>= 6.5 (RO)

Report Only Average Monthly 2.8 1.16 14.3 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3.2 8.5 0.01 31.8 1.16 14.3

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 3 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 4/19/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 4/2/2024 1.16 Result from 24-hour composite collected 4/1/24-4/2/24 CWB Zinc Total Micrograms/L (ug/L) 4/2/2024 14.3 Result from 24-hour composite collected 4/1/24-4/2/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 3 Monitoring Period:04/01/2024 - 04/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-M 4/1/24 23.7 1-T 4/2/24 24.6 1-W 4/3/24 23.5 1-Th 4/4/24 22.1 1-F 4/5/24 22.5 1-Sa 4/6/24 23.3 2-Su 4/7/24 23.1 2-M 4/8/24 23.1 2-T 4/9/24 24.2 2-W 4/10/24 23.4 2-Th 4/11/24 23.4 2-F 4/12/24 24.0 2-Sa 4/13/24 23.9 3-Su 4/14/24 24.7 3-M 4/15/24 24.1 3-T 4/16/24 23.4 3-W 4/17/24 23.3 3-Th 4/18/24 21.6 3-F 4/19/24 21.3 3-Sa 4/20/24 23.9 4-Su 4/21/24 24.1 4-M 4/22/24 23.4 4-T 4/23/24 23.8 4-W 4/24/24 24.1 4-Th 4/25/24 24.0 4-F 4/26/24 24.3 4-Sa 4/27/24 23.9 5-Su 4/28/24 24.0 5-M 4/29/24 23.4 5-T 4/30/24 23.0 Average Monthly 23.5 Report Only Monthly Total 705.1 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 5/14/2024 8:45:28 PM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-058 DIC: 1316.20 DATE:

June 12, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station May 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for May 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, May 2024 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

T Fitzpatric (via email)

Document Control (via APW)

Columbia Generating Station Page 2 of 2 September 30, 2024 Columbia Generating Station May 2024 NPDES Discharge Monitoring Report I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Tim Fitzpatric, Water Treatment Op/Env. Scientist, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 3 Monitoring Period:05/01/2024 - 05/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-W 5/1/24 3.0 7.8 8.0 0.01 25.4 1-Th 5/2/24 3.0 7.8 8.0 0.00 25.3 1-F 5/3/24 3.0 7.7 8.0 0.01 26.3 1-Sa 5/4/24 3.0 7.7 7.9 0.01 27.9 2-Su 5/5/24 3.0 7.7 8.0 0.01 27.6 2-M 5/6/24 3.0 7.7 8.0 0.01 26.3 2-T 5/7/24 3.0 7.7 8.0 0.01 25.7 1.38*

13.7*

2-W 5/8/24 2.7 7.8 8.0 0.01 25.7 2-Th 5/9/24 2.6 7.7 8.0 0.01 26.7 2-F 5/10/24 2.5 7.7 7.9 0.01 27.4 2-Sa 5/11/24 2.5 7.7 7.9 0.01 28.1 3-Su 5/12/24 2.6 7.7 8.0 0.01 28.2 3-M 5/13/24 2.6 7.7 8.0 0.01 28.3 3-T 5/14/24 2.6 7.7 7.9 0.01 28.2 3-W 5/15/24 2.6 7.7 7.9 0.01 27.8 3-Th 5/16/24 2.6 7.7 7.9 0.01 28.7 3-F 5/17/24 2.6 7.7 7.9 0.00 29.0 3-Sa 5/18/24 2.6 7.7 7.9 0.00 25.7 4-Su 5/19/24 2.6 7.7 7.9 0.00 26.4 4-M 5/20/24 2.6 7.7 7.9 0.00 26.0 4-T 5/21/24 2.6 7.7 8.0 0.00 26.6 4-W 5/22/24 2.6 7.8 7.9 0.01 26.5 4-Th 5/23/24 2.6 7.7 7.9 0.00 26.2 4-F 5/24/24 2.6 7.6 7.9 0.00 26.3 4-Sa 5/25/24 2.6 7.7 7.9 0.00 26.2 5-Su 5/26/24 2.6 7.7 7.9 0.00 26.3 5-M 5/27/24 2.6 7.7 7.9 0.00 27.2 5-T 5/28/24 2.6 7.7 7.9 0.00 27.5 5-W 5/29/24 2.6 7.7 7.9 0.00 27.3 5-Th 5/30/24 2.6 7.7 7.9 0.00 26.1 5-F 5/31/24 2.6 7.7 8.0 M

0.01 26.2 Daily Minimum 7.6 16.9

>= 6.5 (RO)

Report Only Average Monthly 2.7 1.38 13.7 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3

8 0.01 29 1.38 13.7

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total M

Report Only Report Only Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 3 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Chromium Total Micrograms/L (ug/L) 5/7/2024 1.38 Result from 24-hour composite collected 5/6/24-5/7/24 CWB Zinc Total Micrograms/L (ug/L) 5/7/2024 13.7 Result from 24-hour composite collected 5/6/24-5/7/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 3 Monitoring Period:05/01/2024 - 05/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-W 5/1/24 23.1 1-Th 5/2/24 19.5 1-F 5/3/24 24.1 1-Sa 5/4/24 24.3 2-Su 5/5/24 23.3 2-M 5/6/24 23.7 2-T 5/7/24 23.7 2-W 5/8/24 23.9 2-Th 5/9/24 24.4 2-F 5/10/24 25.2 2-Sa 5/11/24 25.8 3-Su 5/12/24 26.3 3-M 5/13/24 25.6 3-T 5/14/24 25.7 3-W 5/15/24 25.1 3-Th 5/16/24 25.5 3-F 5/17/24 24.3 3-Sa 5/18/24 24.0 4-Su 5/19/24 23.9 4-M 5/20/24 24.3 4-T 5/21/24 23.5 4-W 5/22/24 23.3 4-Th 5/23/24 23.7 4-F 5/24/24 24.2 4-Sa 5/25/24 24.1 5-Su 5/26/24 24.0 5-M 5/27/24 24.6 5-T 5/28/24 24.6 5-W 5/29/24 23.8 5-Th 5/30/24 23.9 5-F 5/31/24 24.4 Average Monthly 24.2 Report Only Monthly Total 749.8 Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 6/12/2024 12:30:44 PM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-065 DIC: 1316.20 DATE:

July 15, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station June 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for June 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, June 2024 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

Document Control (via APW)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of

Columbia Generating Station Page 2 of 2 July 15, 2024 Columbia Generating Station June 2024 NPDES Discharge Monitoring Report the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Devon Van Alyne, Laboratory Services Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:06/01/2024 - 06/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB 1-Sa 6/1/24 2.6 7.7 7.9 0.01 26.5 2-Su 6/2/24 2.3 7.7 7.9 0.01 26.9 2-M 6/3/24 C

C C

0 C

C 2-T 6/4/24 1.0 8.1 8.2 M*

28.8 2-W 6/5/24 3.2 7.4 8.2 0.00 29.0 2-Th 6/6/24 3.2 7.7 7.9 0.00 27.5 1.78*

15.5*

2-F 6/7/24 3.2 7.7 7.9 0.00 27.7 2-Sa 6/8/24 3.2 7.6 7.8 0.00 28.0 3-Su 6/9/24 3.2 7.6 7.8 0.00 29.1 3-M 6/10/24 3.2 7.5 7.7 0.00 29.4 3-T 6/11/24 3.0 7.5 7.7 0.01 28.8 3-W 6/12/24 2.6 7.5 7.7 0.01 28.6 3-Th 6/13/24 2.6 7.6 7.8 0.01 26.9 3-F 6/14/24 2.6 7.6 7.8 0.00 26.9 3-Sa 6/15/24 2.6 7.6 7.7 0.00 26.9 4-Su 6/16/24 2.6 7.6 7.8 0.00 26.9 4-M 6/17/24 2.6 7.6 7.8 0.00 26.6 4-T 6/18/24 2.6 7.7 7.8 0.00 27.3 4-W 6/19/24 2.6 7.6 7.8 0.00 27.6 4-Th 6/20/24 2.6 7.6 7.8 0.00 27.9 4-F 6/21/24 2.6 7.6 7.8 0.01 28.2 4-Sa 6/22/24 2.5 7.6 7.8 0.01 29.4 5-Su 6/23/24 2.6 7.6 7.7 0.02 29.2 5-M 6/24/24 2.6 7.6 7.8 0.01 29.1 5-T 6/25/24 2.6 7.6 7.8 0.00 28.8 5-W 6/26/24 2.6 7.6 7.8 0.00 29.4 5-Th 6/27/24 1.5 7.5 8.0 0.00 29.1 5-F 6/28/24 2.5 7.5 7.7 0.00 28.4 5-Sa 6/29/24 1.2 7.5 8.1 0.01 27.8 6-Su 6/30/24 5.0 7.6 8.1 0.00 30.3 2.56E+08 Daily Minimum 7.4 22.0

>= 6.5 (RO)

Report Only Average Monthly 2.6 2.56e+008 1.78 15.5 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 5

8.2 0.02 30.3 1.78 15.5

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Monitoring Point Week SSWD 1-Sa 6/1/24 2-Su 6/2/24 2-M 6/3/24 2-T 6/4/24 2-W 6/5/24 2-Th 6/6/24 2-F 6/7/24 2-Sa 6/8/24 3-Su 6/9/24 3-M 6/10/24 3-T 6/11/24 3-W 6/12/24 3-Th 6/13/24 3-F 6/14/24 3-Sa 6/15/24 4-Su 6/16/24 4-M 6/17/24 4-T 6/18/24 4-W 6/19/24 4-Th 6/20/24 4-F 6/21/24 4-Sa 6/22/24 5-Su 6/23/24 5-M 6/24/24 5-T 6/25/24 5-W 6/26/24 5-Th 6/27/24 5-F 6/28/24 5-Sa 6/29/24 6-Su 6/30/24 Daily Minimum Average Monthly Report Only Daily Maximum Monthly Total Report Only

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 6/4/2024 MlM Halogenation not in service 6/2/24 1230- 6/5/24 1230 CWB Chromium Total Micrograms/L (ug/L) 6/6/2024 1.78 Result from 24-hour composite collected 6/5/24-6/6/24 CWB Zinc Total Micrograms/L (ug/L) 6/6/2024 15.5 Result from 24-hour composite collected 6/5/24-6/6/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:06/01/2024 - 06/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-Sa 6/1/24 24.5 2-Su 6/2/24 23.7 2-M 6/3/24 22.0 2-T 6/4/24 22.9 2-W 6/5/24 25.1 2-Th 6/6/24 25.8 2-F 6/7/24 26.6 2-Sa 6/8/24 26.5 3-Su 6/9/24 25.5 3-M 6/10/24 19.6 3-T 6/11/24 23.1 3-W 6/12/24 24.5 3-Th 6/13/24 25.1 3-F 6/14/24 25.1 3-Sa 6/15/24 24.3 4-Su 6/16/24 23.5 4-M 6/17/24 23.8 4-T 6/18/24 24.1 4-W 6/19/24 24.9 4-Th 6/20/24 26.0 4-F 6/21/24 26.0 4-Sa 6/22/24 26.5 5-Su 6/23/24 25.4 5-M 6/24/24 24.8 5-T 6/25/24 25.7 5-W 6/26/24 25.7 5-Th 6/27/24 23.6 5-F 6/28/24 24.4 5-Sa 6/29/24 23.5 6-Su 6/30/24 27.9 Average Monthly 24.7 Report Only Monthly Total 740.1 Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 7/15/2024 12:24:47 PM

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1941125 - 7/15/2024 12:24:50 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only zBkLui3srNXERWh2gZUeSqj62Mn0i1iL9XMONCQ9YTbIbVC6Oz2ftI1kgECTn7gGe7xL7oL7gTYJXDkwxVp6R7Pm1hGuJ xM6ANO8VathESI=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Monday July 15 2024 Report Received: 2024-07-15 12:24 Page 1 of 1 Pages

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-074 DIC: 1316.20 DATE:

August 14, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station July 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for July 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, July 2024 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

Document Control (via APW)

Columbia Generating Station Page 2 of 2 August 15, 2024 Columbia Generating Station July 2024 NPDES Discharge Monitoring Report I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Tim Fitzpatric, Water Treatment Op/Env. Scientist, Environmental Services Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1945539 - 8/14/2024 8:49:00 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only 7IDtxxFRBGN3AemnZluwXMeaJPjzs9xyVFsxWY

+vPuJ3qqkiIDV48p6fA2fJvRipUMJVHPUWvuvBQFeZu/lyI0/QCTMfZwukQ877rCxcKLE=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday August 14 2024 Report Received: 2024-08-14 20:49 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:07/01/2024 - 07/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB 1-M 7/1/24 5.0 7.5 7.7 0.00 30.7 1-T 7/2/24 5.0 7.5 7.7 0.00 30.4 1.54*

15.9*

1-W 7/3/24 5.0 7.5 7.7 0.00 30.0 1-Th 7/4/24 5.0 7.5 7.9 0.00 29.2 1-F 7/5/24 5.0 7.7 7.9 0.00 30.4 1-Sa 7/6/24 4.9 7.7 7.8 0.00 30.6 2-Su 7/7/24 4.9 7.7 7.8 0.00 31.3 2-M 7/8/24 4.9 7.7 8.0 0.00 31.0 2-T 7/9/24 4.9 7.7 7.9 0.00 31.3 2-W 7/10/24 4.9 7.7 8.0 0.00 32.1 2-Th 7/11/24 4.9 7.7 7.9 0.01 31.3 2-F 7/12/24 4.9 7.7 7.9 0.01 30.7 2-Sa 7/13/24 4.8 7.7 7.9 0.01 32.5 3-Su 7/14/24 4.8 7.7 7.9 0.00 33.3 3-M 7/15/24 4.8 7.7 7.9 0.00 32.9 3-T 7/16/24 4.8 7.7 7.9 0.01 33.2 3-W 7/17/24 4.8 7.6 7.8 0.01 32.8 3-Th 7/18/24 4.8 7.7 7.9 0.01 34.4 3-F 7/19/24 4.8 7.7 7.9 0.01 34.1 3-Sa 7/20/24 4.8 7.6 7.9 0.00 33.5 4-Su 7/21/24 4.8 7.7 7.9 0.00 34.4 4-M 7/22/24 4.8 7.7 7.9 0.00 34.5 4-T 7/23/24 4.8 7.7 7.9 0.00 32.8 4-W 7/24/24 4.8 7.7 7.9 0.00 33.8 4-Th 7/25/24 4.8 7.7 7.9 0.00 33.5 4-F 7/26/24 4.8 7.7 8.0 0.00 31.6 4-Sa 7/27/24 4.8 7.9 8.0 0.00 32.3 5-Su 7/28/24 4.8 7.8 8.0 0.00 32.8 5-M 7/29/24 4.8 7.8 8.0 0.00 33.8 5-T 7/30/24 4.8 7.8 8.0 0.00 33.4 5-W 7/31/24 4.8 7.8 8.0 M

0.00 34.1 5.61E+08 Daily Minimum 7.5 25.4

>= 6.5 (RO)

Report Only Average Monthly 4.9 5.61e+008 1.54 15.9 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 5.0 8.0 0.01 34.5 1.54 15.9

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total M

Report Only Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Monitoring Point Week SSWD 1-M 7/1/24 1-T 7/2/24 1-W 7/3/24 1-Th 7/4/24 1-F 7/5/24 1-Sa 7/6/24 2-Su 7/7/24 2-M 7/8/24 2-T 7/9/24 2-W 7/10/24 2-Th 7/11/24 2-F 7/12/24 2-Sa 7/13/24 3-Su 7/14/24 3-M 7/15/24 3-T 7/16/24 3-W 7/17/24 3-Th 7/18/24 3-F 7/19/24 3-Sa 7/20/24 4-Su 7/21/24 4-M 7/22/24 4-T 7/23/24 4-W 7/24/24 4-Th 7/25/24 4-F 7/26/24 4-Sa 7/27/24 5-Su 7/28/24 5-M 7/29/24 5-T 7/30/24 5-W 7/31/24 Daily Minimum Average Monthly Report Only Daily Maximum Monthly Total Report Only

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Chromium Total Micrograms/L (ug/L) 7/2/2024 1.54 Result from 24-hour composite collected 7/1/24-7/2/24 CWB Zinc Total Micrograms/L (ug/L) 7/2/2024 15.9 Result from 24-hour composite collected 7/1/24-7/2/24 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:07/01/2024 - 07/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-M 7/1/24 26.9 1-T 7/2/24 27.1 1-W 7/3/24 26.7 1-Th 7/4/24 27.5 1-F 7/5/24 28.2 1-Sa 7/6/24 29.0 2-Su 7/7/24 28.9 2-M 7/8/24 29.5 2-T 7/9/24 28.7 2-W 7/10/24 29.4 2-Th 7/11/24 28.4 2-F 7/12/24 28.9 2-Sa 7/13/24 29.2 3-Su 7/14/24 30.0 3-M 7/15/24 29.7 3-T 7/16/24 29.7 3-W 7/17/24 24.3 3-Th 7/18/24 28.7 3-F 7/19/24 29.2 3-Sa 7/20/24 29.5 4-Su 7/21/24 29.2 4-M 7/22/24 27.5 4-T 7/23/24 27.3 4-W 7/24/24 28.0 4-Th 7/25/24 27.2 4-F 7/26/24 26.4 4-Sa 7/27/24 26.9 5-Su 7/28/24 27.5 5-M 7/29/24 26.6 5-T 7/30/24 27.0 5-W 7/31/24 27.0 Average Monthly 28.1 Report Only Monthly Total 870.1 Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 8/14/2024 8:48:56 PM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-083 DIC: 1316.20 DATE:

September 11, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station August 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for August 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, August 2024 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

T Williams (via email)

Document Control (via APW)

J Laporte (via email)

D Van Alyne (via email)

M. Ramos (via email)

Columbia Generating Station Page 2 of 2 September 12, 2024 Columbia Generating Station August 2024 NPDES Discharge Monitoring Report I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Reviewed by: Joshua Laporte, Environmental Scientist Pr, Environmental & Regulatory Programs Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Devon Van Alyne, Laboratory Services Manager Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1948497 - 9/11/2024 3:15:19 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only aSMGJUMuwGCFAIpErKoQ/2fZOFxYfTQku2Isp1w65xy4/qgfSAnb9U1lHfEQf3e

+4TyaSLEVkPqay/nieRsi7mn2aRwlCc5B228fDkpxyFA=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday September 11 2024 Report Received: 2024-09-11 15:15 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:08/01/2024 - 08/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB 1-Th 8/1/24 4.7 7.8 8.0 0.00 34.5 1-F 8/2/24 4.4 7.8 8.0 0.00 34.7 1-Sa 8/3/24 4.4 7.8 8.0 0.00 34.8 2-Su 8/4/24 4.4 7.8 8.0 0.00 32.0 2-M 8/5/24 4.4 7.8 8.0 0.00 32.3 2-T 8/6/24 4.4 7.8 8.5 0.00 32.3 1.41*

11.5*

2-W 8/7/24 2.5 7.9 8.4 0

0.00 31.6 2-Th 8/8/24 4.2 7.8 8.1 0.00 32.0 2-F 8/9/24 4.2 7.8 8.0 0.00 31.8 2-Sa 8/10/24 4.2 7.8 8.0 0.00 32.2 3-Su 8/11/24 4.2 7.8 8.0 0.00 32.2 3-M 8/12/24 4.3 7.8 8.0 0.00 31.8 3-T 8/13/24 4.3 7.8 8.0 0.00 30.6 3-W 8/14/24 4.3 7.8 8.0 0.00 30.7 3-Th 8/15/24 4.3 7.8 8.0 0.00 31.6 3-F 8/16/24 4.2 7.8 8.0 0.00 31.1 3-Sa 8/17/24 4.2 7.8 8.0 0.00 32.3 4-Su 8/18/24 4.3 7.8 8.0 0.00 32.4 4-M 8/19/24 4.3 7.8 8.0 0.00 31.0 4-T 8/20/24 4.2 7.8 8.0 0.00 30.3 4-W 8/21/24 4.3 7.8 8.0 0.00 30.3 4-Th 8/22/24 4.3 7.8 8.0 0.00 30.6 4-F 8/23/24 4.3 7.8 8.0 0.00 30.3 4-Sa 8/24/24 4.3 7.8 8.0 0.00 29.5 5-Su 8/25/24 4.3 7.8 8.0 0.00 29.4 5-M 8/26/24 4.3 7.8 8.0 0.00 30.3 5-T 8/27/24 4.3 7.8 8.0 0.00 30.1 5-W 8/28/24 4.3 7.8 8.0 0.00 29.3 5-Th 8/29/24 4.3 7.8 8.0 0.00 29.2 5-F 8/30/24 4.3 7.7 7.9 0.00 30.0 5-Sa 8/31/24 4.3 7.7 7.9 0.00 30.4 4.72E+08 Daily Minimum 7.7 25.4

>= 6.5 (RO)

Report Only Average Monthly 4.2 4.72e+008 1.41 11.5 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 4.7 8.5 0

34.8 1.41 11.5

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Reporting Codes Used: C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Monitoring Point Week SSWD 1-Th 8/1/24 1-F 8/2/24 1-Sa 8/3/24 2-Su 8/4/24 2-M 8/5/24 2-T 8/6/24 2-W 8/7/24 2-Th 8/8/24 2-F 8/9/24 2-Sa 8/10/24 3-Su 8/11/24 3-M 8/12/24 3-T 8/13/24 3-W 8/14/24 3-Th 8/15/24 3-F 8/16/24 3-Sa 8/17/24 4-Su 8/18/24 4-M 8/19/24 4-T 8/20/24 4-W 8/21/24 4-Th 8/22/24 4-F 8/23/24 4-Sa 8/24/24 5-Su 8/25/24 5-M 8/26/24 5-T 8/27/24 5-W 8/28/24 5-Th 8/29/24 5-F 8/30/24 5-Sa 8/31/24 Daily Minimum Average Monthly Report Only Daily Maximum Monthly Total Report Only

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Chromium Total Micrograms/L (ug/L) 8/6/2024 1.41 Sample collected 8/5/24-8/6/24 as 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite CWB Zinc Total Micrograms/L (ug/L) 8/6/2024 11.5 Sample collected 8/5/24-8/6/24 as 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:08/01/2024 - 08/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-Th 8/1/24 28.0 1-F 8/2/24 28.9 1-Sa 8/3/24 27.9 2-Su 8/4/24 28.0 2-M 8/5/24 27.5 2-T 8/6/24 27.5 2-W 8/7/24 25.2 2-Th 8/8/24 27.5 2-F 8/9/24 27.8 2-Sa 8/10/24 27.9 3-Su 8/11/24 26.8 3-M 8/12/24 27.5 3-T 8/13/24 26.0 3-W 8/14/24 26.0 3-Th 8/15/24 25.7 3-F 8/16/24 26.2 3-Sa 8/17/24 27.4 4-Su 8/18/24 26.3 4-M 8/19/24 26.9 4-T 8/20/24 25.6 4-W 8/21/24 25.6 4-Th 8/22/24 25.8 4-F 8/23/24 25.1 4-Sa 8/24/24 24.3 5-Su 8/25/24 24.8 5-M 8/26/24 25.1 5-T 8/27/24 25.3 5-W 8/28/24 24.5 5-Th 8/29/24 24.9 5-F 8/30/24 25.4 5-Sa 8/31/24 26.2 Average Monthly 26.4 Report Only Monthly Total 817.6 Report Only Reporting Codes Used: C - No Discharge Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 9/11/2024 3:15:13 PM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-094 DIC: 1316.20 DATE:

October 14, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station September 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for September 2024. All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

Attachment:

NPDES Discharge Monitoring Report, September 2024 KRB

Columbia Generating Station Page 2 of 2 October 14, 2024 Columbia Generating Station September 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

T Williams (via email)

Document Control (via APW)

J Laporte (via email)

S Lofland (via email)

M. Ramos (via email)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Sam Lofland, Water Operator/Environmental Technician, Environmental Services Reviewed by: Joshua Laporte, Environmental Scientist Pr, Environmental & Regulatory Programs Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:09/01/2024 - 09/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB 1-Su 9/1/24 4.3 7.7 7.9 0.01 31.7 1-M 9/2/24 4.3 7.7 7.9 0.01 32.5 1-T 9/3/24 4.3 7.7 7.9 0.01 31.9 1.34*

8.70*

1-W 9/4/24 4.3 7.7 7.9 0.01 31.8 1-Th 9/5/24 4.3 7.7 7.9 0.01 31.7 1-F 9/6/24 4.3 7.7 7.9 0.00 32.0 1-Sa 9/7/24 4.3 7.7 7.9 0.00 31.7 2-Su 9/8/24 4.3 7.7 7.9 0.01 32.8 2-M 9/9/24 4.2 7.7 7.9 0.01 31.9 2-T 9/10/24 4.2 7.7 7.9 0.01 31.3 2-W 9/11/24 4.2 7.7 7.9 0.01 30.4 2-Th 9/12/24 4.2 7.8 7.9 0.01 30.5 2-F 9/13/24 4.2 7.8 8.0 0.01 30.3 2-Sa 9/14/24 4.3 7.7 7.9 0.01 30.8 3-Su 9/15/24 4.3 7.8 7.9 0.01 30.3 3-M 9/16/24 4.3 7.8 7.9 0.01 29.9 3-T 9/17/24 3.9 7.7 8.0 0.01 30.7 3-W 9/18/24 0.9 7.8 7.9 0

0.01 30.0 3-Th 9/19/24 C

C C

C C

C C

3-F 9/20/24 C

C C

C C

C C

3-Sa 9/21/24 1.3 7.6 8.4 0

0.01

<0.1*

27.7 4-Su 9/22/24 2.7 7.8 8.0 0.00 28.2 4-M 9/23/24 2.7 7.7 7.9 0.00 30.7 4-T 9/24/24 2.7 7.8 7.9 0.00 30.8 4-W 9/25/24 2.5 7.7 7.9 0

0.00

<0.1*

32.0 4-Th 9/26/24 3.0 7.8 8.0 0.00 29.7 4-F 9/27/24 1.7 7.8 8.2 0

0.00 30.0 4-Sa 9/28/24 2.8 8.1 8.3 0.00 29.7 5-Su 9/29/24 2.9 8.1 8.2 0.00 29.5 5-M 9/30/24 2.9 7.8 8.3 0.00 27.9 3.62E+08 Daily Minimum 7.6 22.2

>= 6.5 (RO)

Report Only Average Monthly 3.3 3.62e+008 1.34 8.7 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 4.3 8.4 0.01 32.8 1.34 8.7

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Monitoring Point Week SSWD 1-Su 9/1/24 1-M 9/2/24 1-T 9/3/24 1-W 9/4/24 1-Th 9/5/24 1-F 9/6/24 1-Sa 9/7/24 2-Su 9/8/24 2-M 9/9/24 2-T 9/10/24 2-W 9/11/24 2-Th 9/12/24 2-F 9/13/24 2-Sa 9/14/24 3-Su 9/15/24 3-M 9/16/24 3-T 9/17/24 3-W 9/18/24 3-Th 9/19/24 3-F 9/20/24 3-Sa 9/21/24 4-Su 9/22/24 4-M 9/23/24 4-T 9/24/24 4-W 9/25/24 4-Th 9/26/24 4-F 9/27/24 4-Sa 9/28/24 5-Su 9/29/24 5-M 9/30/24 Daily Minimum Average Monthly Report Only Daily Maximum Monthly Total Report Only

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:09/01/2024 - 09/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-Su 9/1/24 26.5 1-M 9/2/24 27.1 1-T 9/3/24 26.4 1-W 9/4/24 26.3 1-Th 9/5/24 26.8 1-F 9/6/24 26.9 1-Sa 9/7/24 26.7 2-Su 9/8/24 27.1 2-M 9/9/24 26.9 2-T 9/10/24 26.8 2-W 9/11/24 25.8 2-Th 9/12/24 26.3 2-F 9/13/24 25.5 2-Sa 9/14/24 25.5 3-Su 9/15/24 24.8 3-M 9/16/24 25.1 3-T 9/17/24 24.5 3-W 9/18/24 22.1 3-Th 9/19/24 21.5 3-F 9/20/24 21.0 3-Sa 9/21/24 14.5 4-Su 9/22/24 18.2 4-M 9/23/24 24.1 4-T 9/24/24 24.2 4-W 9/25/24 24.2 4-Th 9/26/24 23.8 4-F 9/27/24 22.8 4-Sa 9/28/24 23.4 5-Su 9/29/24 23.7 5-M 9/30/24 22.7 Average Monthly 24.4 Report Only Monthly Total 731.2 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 10/14/2024 1:24:25 PM

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 9/21/2024 Bl<0.1 TRH verification prior to restoration of Blowdown CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 9/25/2024 Bl<0.1 TRH verification prior to restoration of Blowdown CWB Chromium Total Micrograms/L (ug/L) 9/3/2024 1.34 Sample collected 9/2/24-9/3/24 as 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite CWB Zinc Total Micrograms/L (ug/L) 9/3/2024 8.70 Sample collected 9/2/24-9/3/24 as 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite SSWD All Parameters C

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1952909 - 10/14/2024 1:24:28 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only N5GDuvB4VskFnL7Yvs5lHbTqJ3l9L+nMSIv7LUW22uOWBvNLYJKLUK7TmChuvSjYzbELu/DY8HMvs0QIx

+NKC53MPhy/+GfyCJQO7tAkntI=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Monday October 14 2024 Report Received: 2024-10-14 13:24 Page 1 of 1 Pages

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-115 DIC: 1316.20 DATE:

November 13th, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station October 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for October 2024.

All monitoring parameters were within permit specifications for the month.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Josh LaPorte at (509) 377-1084.

Attachment:

NPDES Discharge Monitoring Report, October 2024 KRB

Columbia Generating Station Page 2 of 2 November 13, 2024 Columbia Generating Station October 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

T Williams (via email)

Document Control (via APW)

J Laporte (via email)

S Lofland (via email)

M. Ramos (via email)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Sam Lofland, Water Operator/Environmental Technician, Environmental Services Reviewed by: Joshua Laporte, Environmental Scientist Pr, Environmental & Regulatory Programs Reviewed by: Denis Mehinagic, Environmental & Regulatory Programs Lead Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:10/01/2024 - 10/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB 1-T 10/1/24 2.9 7.8 8.0 0.00 26.5 1-W 10/2/24 2.9 7.8 7.9 0.00 27.0 2.21*

15.2*

1-Th 10/3/24 2.9 7.8 8.0 0.00 25.8 1-F 10/4/24 2.8 7.8 8.0 0.00 27.4 1-Sa 10/5/24 2.9 7.8 8.0 0.00 26.5 2-Su 10/6/24 2.9 7.8 7.9 0.00 26.7 2-M 10/7/24 2.9 7.8 8.1 0.00 27.0 2-T 10/8/24 2.9 8.0 8.2 0.00 28.8 2-W 10/9/24 2.8 8.0 8.1 0.00 28.8 2-Th 10/10/24 2.9 8.0 8.2 0.00 28.0 2-F 10/11/24 2.9 8.0 8.2 0.00 26.2 2-Sa 10/12/24 2.9 8.0 8.1 0.00 27.3 3-Su 10/13/24 2.9 8.0 8.1 0.00 27.3 3-M 10/14/24 2.9 7.9 8.1 0.00 28.6 3-T 10/15/24 2.8 8.0 8.2 0.00 29.0 3-W 10/16/24 2.8 8.0 8.2 0.00 29.4 3-Th 10/17/24 2.8 8.0 8.2 0.00 27.9 3-F 10/18/24 2.8 8.0 8.2 0.00 27.0 3-Sa 10/19/24 2.8 7.9 8.1 0.00 29.4 4-Su 10/20/24 2.8 8.0 8.1 0.01 30.9 4-M 10/21/24 2.4 8.0 8.1 0.01 30.7 4-T 10/22/24 2.1 8.0 8.1 0.01 29.0 4-W 10/23/24 2.1 8.0 8.1 0.00 28.2 4-Th 10/24/24 2.1 8.0 8.2 0.01 28.1 4-F 10/25/24 2.1 7.9 8.1 0.01 26.3 4-Sa 10/26/24 2.1 8.0 8.1 0.01 27.6 5-Su 10/27/24 2.1 7.9 8.1 0.01 30.6 5-M 10/28/24 2.1 8.0 8.1 0.01 28.0 5-T 10/29/24 2.1 8.0 8.1 0.01 26.7 5-W 10/30/24 2.1 8.0 8.1 0.01 26.6 5-Th 10/31/24 2.1 8.0 8.2 M

0.01 M

26.2 2.55E+08 Daily Minimum 7.8 21.8

>= 6.5 (RO)

Report Only Average Monthly 2.6 2.55e+008 2.21 15.2 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 2.9 8.2 0.01 30.9 2.21 15.2

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total M

Report Only Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Monitoring Point Week SSWD 1-T 10/1/24 1-W 10/2/24 1-Th 10/3/24 1-F 10/4/24 1-Sa 10/5/24 2-Su 10/6/24 2-M 10/7/24 2-T 10/8/24 2-W 10/9/24 2-Th 10/10/24 2-F 10/11/24 2-Sa 10/12/24 3-Su 10/13/24 3-M 10/14/24 3-T 10/15/24 3-W 10/16/24 3-Th 10/17/24 3-F 10/18/24 3-Sa 10/19/24 4-Su 10/20/24 4-M 10/21/24 4-T 10/22/24 4-W 10/23/24 4-Th 10/24/24 4-F 10/25/24 4-Sa 10/26/24 5-Su 10/27/24 5-M 10/28/24 5-T 10/29/24 5-W 10/30/24 5-Th 10/31/24 Daily Minimum Average Monthly Report Only Daily Maximum Monthly Total Report Only

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Chromium Total Micrograms/L (ug/L) 10/2/2024 2.21 Sample collected 10/1/24-10/2/24 as 24-hour composite CWB Zinc Total Micrograms/L (ug/L) 10/2/2024 15.2 Sample collected 10/1/24-10/2/24 as 24-hour composite SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:10/01/2024 - 10/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-T 10/1/24 23.0 1-W 10/2/24 23.5 1-Th 10/3/24 22.6 1-F 10/4/24 23.6 1-Sa 10/5/24 22.8 2-Su 10/6/24 22.8 2-M 10/7/24 23.0 2-T 10/8/24 23.2 2-W 10/9/24 23.5 2-Th 10/10/24 23.1 2-F 10/11/24 22.5 2-Sa 10/12/24 23.1 3-Su 10/13/24 23.1 3-M 10/14/24 23.1 3-T 10/15/24 23.6 3-W 10/16/24 23.4 3-Th 10/17/24 23.0 3-F 10/18/24 22.7 3-Sa 10/19/24 24.4 4-Su 10/20/24 24.8 4-M 10/21/24 23.3 4-T 10/22/24 22.2 4-W 10/23/24 21.3 4-Th 10/24/24 22.2 4-F 10/25/24 21.5 4-Sa 10/26/24 22.8 5-Su 10/27/24 23.0 5-M 10/28/24 22.8 5-T 10/29/24 21.8 5-W 10/30/24 21.2 5-Th 10/31/24 21.6 Average Monthly 22.9 Report Only Monthly Total 708.5 Report Only Reporting Codes Used: C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1 I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 11/13/2024 12:00:54 PM

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1957497 - 11/13/2024 12:00:57 PM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only S8gqY6Sxq5WjqP2J4CAYs+cP26yI5Og47D9VfhCk65nsVgXtsR9RN5z/bxFgBHJa7s/kjUvdoowSckc

+ZhDqEiSiaQx91mpmAZd6CcJNQwI=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday November 13 2024 Report Received: 2024-11-13 12:00 Page 1 of 1 Pages

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-129 DIC: 1316.20 DATE:

December 11th, 2024 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station November 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for November 2024.

All monitoring parameters were within permit specifications for the month.

During the month of November 2024, maintenance was performed on the 4.16KV Switchgear E-SM-75/72 which caused a loss of power to the Tower Makeup Water (TMU) intake flowmeter L002-Flow on November 10th-13th, 15th-16th, and 22nd-24th. TMU flows on these days were obtained by calculating the average of the available hourly flow data for that day or days, or calculating the average of the bracketing days with available TMU flow data. This is not a permit violation.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Josh LaPorte at (509) 377-1084.

Attachment:

NPDES Discharge Monitoring Report, November 2024 KRB

Columbia Generating Station Page 2 of 2 December 11, 2024 Columbia Generating Station November 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

D Mehinagic (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

T Williams (via email)

Document Control (via APW)

J Laporte (via email)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Traci Williams, Environmental Services Supervisor, Environmental Services Reviewed by: Joshua Laporte, Environmental Scientist Pr, Environmental & Regulatory Programs Approved by: Denis Mehinagic, Environmental & Regulatory Programs Supervisor

Company Name Signer Name System Name Energy Northwest Denis Mehinagic WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1961114 - 12/11/2024 11:11:06 AM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only xtzls8E3iexEiN7uq4hFl0vVvVk8nrK9yLkT3SaV2DHPan9nOwv2gcZ6MxLWnblzOo1P3jB7Md6owS1LXxkDo

+0mGum2RC4NxYnBnPToF3A=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday December 11 2024 Report Received: 2024-12-11 11:11 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:11/01/2024 - 11/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-F 11/1/24 2.0 8.0 8.1 0.00 27.8 1-Sa 11/2/24 2.0 8.0 8.1 0.01 27.5 2-Su 11/3/24 2.0 8.0 8.1 0.01 27.3 2-M 11/4/24 2.0 7.9 8.1 0.01 28.7 2-T 11/5/24 2.0 7.9 8.0 0.02 28.3 2.06*

17.8*

2-W 11/6/24 2.1 7.9 8.1 0.01 26.1 2-Th 11/7/24 2.1 8.0 8.2 0.00 26.0 2-F 11/8/24 2.1 8.0 8.1 0.01 25.4 2-Sa 11/9/24 2.1 8.0 8.1 0.01 25.4 3-Su 11/10/24 2.1 7.9 8.0 0.01 26.0 3-M 11/11/24 2.1 7.9 8.1 0.01 25.9 3-T 11/12/24 2.1 7.9 8.0 0.01 25.2 3-W 11/13/24 2.1 7.8 8.3 0.01 27.6 3-Th 11/14/24 2.1 7.8 8.3 0.01 28.2 3-F 11/15/24 2.2 7.9 8.0 0.01 26.9 3-Sa 11/16/24 2.2 7.9 8.0 0.01 26.9 4-Su 11/17/24 2.2 7.9 8.0 0.01 29.8 4-M 11/18/24 2.2 7.9 8.1 0.01 28.9 4-T 11/19/24 2.2 7.9 8.1 0.01 26.8 4-W 11/20/24 2.2 7.9 8.1 0.01 29.2 4-Th 11/21/24 2.1 7.9 8.1 0.02 27.8 4-F 11/22/24 2.2 7.9 8.0 0.01 28.0 4-Sa 11/23/24 2.2 7.9 8.1 0.01 25.7 5-Su 11/24/24 2.2 7.9 8.0 0.01 26.9 5-M 11/25/24 2.2 7.9 8.0 0.01 28.0 5-T 11/26/24 2.2 7.9 8.0 0.00 27.3 5-W 11/27/24 2.2 7.8 8.0 0.01 26.9 5-Th 11/28/24 0.1 8.0 8.0 0

0.01

<0.1*

25.5 5-F 11/29/24 1.2 7.9 8.1 0.00 25.1 5-Sa 11/30/24 2.3 7.9 8.0 0.00 25.3 Daily Minimum 7.8 21.7

>= 6.5 (RO)

Report Only Average Monthly 2.0 2.06 17.8 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 2.3 8.3 0.02 29.8 2.06 17.8

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 11/28/2024 Bl<0.1 TRH grab sample for verification TRH <0.1 prior to restoring blowdown CWB Chromium Total Micrograms/L (ug/L) 11/5/2024 2.06 Results from 24-hour composite collected 11-4-24 to 11 24.

CWB Zinc Total Micrograms/L (ug/L) 11/5/2024 17.8 Results from 24-hour composite collected 11-4-24 to 11 24.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Monitoring Period:11/01/2024 - 11/30/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-F 11/1/24 22.4 1-Sa 11/2/24 22.4 2-Su 11/3/24 22.2 2-M 11/4/24 22.3 2-T 11/5/24 22.4 2-W 11/6/24 21.0 2-Th 11/7/24 20.5 2-F 11/8/24 20.6 2-Sa 11/9/24 20.2 3-Su 11/10/24 21.2*

3-M 11/11/24 21.8*

3-T 11/12/24 21.8*

3-W 11/13/24 22.4*

3-Th 11/14/24 22.2 3-F 11/15/24 20.7*

3-Sa 11/16/24 21.1*

4-Su 11/17/24 22.0 4-M 11/18/24 21.6 4-T 11/19/24 21.5 4-W 11/20/24 21.1 4-Th 11/21/24 22.1 4-F 11/22/24 21.0*

4-Sa 11/23/24 21.7*

5-Su 11/24/24 22.4*

5-M 11/25/24 17.6 5-T 11/26/24 18.2 5-W 11/27/24 17.3 5-Th 11/28/24 18.0 5-F 11/29/24 18.6 5-Sa 11/30/24 20.3 Average Monthly 21.0 Report Only Monthly Total 628.6 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Outfall: Intk - Cooling water intake structure Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment Intk Flow MGD 11/10/2024 21.2 Partial flow measurement data for this day. Average calculated from 0000-2100 due to maintenance outage flow data unavailable 11/10/24 2200- 11/13/24 1400.

Intk Flow MGD 11/11/2024 21.8 No flow measurement data for this day. Flow is estimated based on average of 11/10/24 and 11/13/24 due to maintenance outage flow data unavailable 11/10/24 2200-11/13/24 1400.

Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Intk Flow MGD 11/12/2024 21.8 No flow measurement data for this day. Flow is estimated based on average of 11/10/24 and 11/13/24 due to maintenance outage flow data unavailable 11/10/24 2200-11/13/24 1400.

Intk Flow MGD 11/13/2024 22.4 Partial flow measurement data for this day. Average calculated from 1400-2300 due to maintenance outage flow data unavailable 11/10/24 2200- 11/13/24 1400.

Intk Flow MGD 11/15/2024 20.7 Partial flow measurement data for this day. Average 11/15/24 0000-1000 due to flow data unavailable Intk Flow MGD 11/16/2024 21.1 Partial flow measurement data for this day. Average 11/16/24 1000-2359 due to flow data unavailable Intk Flow MGD 11/22/2024 21.0 Partial flow measurement data for this day. Average 11/22/24 0000-1500 due to flow data unavailable 11/22/24 1500 to 11/24/24 1600.

Intk Flow MGD 11/23/2024 21.7 No flow measurement data for this day. Flow is estimated based on average of 11/22/24 and 11/24/24 due to flow data unavailable 11/22/24 1500 to 11/24/24 1600.

Intk Flow MGD 11/24/2024 22.4 Partial flow measurement data for this day. Average 11/24/24 1600-2359 due to flow data unavailable 11/22/24 1500 to 11/24/24 1600.

I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Denis Mehinagic Signature Date 12/11/2024 11:11:03 AM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-25-018 DIC: 1316.20 DATE:

January 14, 2025 TO:

Columbia Generating Station (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station December 2024 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for December 2024.

All monitoring parameters were within permit specifications for the month.

During the month of December 2024, TMU intake flows on 12/15-12/16 and 12/30-12/31 were obtained by calculating the average of the available hourly flow data for each day.

This is not a permit violation.

The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. If you have any questions concerning this information, please contact Josh LaPorte at (509) 377-1084.

Attachment:

NPDES Discharge Monitoring Report, December 2024 KRB

Columbia Generating Station Page 2 of 2 February 5, 2025 Columbia Generating Station November 2024 NPDES Discharge Monitoring Report DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

M Ramos (via email)

Docket File PE20 K Byers (via email)

Regulatory (via email)

D Van Alyne (via email)

Document Control (via APW)

J Laporte (via email)

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Prepared by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Devon Van Alyne, Laboratory Services Manager, Environmental Services and Development Reviewed by: Joshua Laporte, Environmental Scientist Pr, Environmental & Regulatory Programs Approved by: Mary Joy Ramos, Environmental & Regulatory Programs Manager

Company Name Signer Name System Name Energy Northwest Mary Joy C. Ramos WQWebPortal Washington Department of Ecology Electronic Submission Cover Letter WQWebDMR - Permit# WA0025151 - DMR Submission Id: 1966348 - 1/15/2025 7:24:37 AM Attachments:

Attestation Agreed to at Signing:

I certify I personally signed and submitted to the Department of Ecology an Electronic Signature Agreement. I understand that use of my electronic signature account/password to submit this information is equal to my written signature. I have read and followed all the rules of use in my Electronic Signature Agreement. I believe no one but me has had access to my password and other account information.

I further certify: I had the opportunity to review the content or meaning of the submittal before signing it; and to the best of my knowledge and belief, the information submitted is true, accurate, and complete. I intend to submit this information as part of the implementation, oversight, and enforcement of a federal environmental program. I am aware there are significant penalties for submitting false information, including possible fines and imprisonment.

For Ecology Use Only 84l5YNhFx8nECAPij8LHPLyMeLERDoyStUOLWZ2v7crKlJIttpjHdcENzexBpsA5ORroDbzf/Y8ReyPxhNeh

+HkZxwxBOpRkaphuzDfPxL0=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Wednesday January 15 2025 Report Received: 2025-01-15 07:24 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:12/01/2024 - 12/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week RWTS CWB CWB CWB CWB CWB CWB CWB CWB CWB SSWD 1-Su 12/1/24 2.3 7.9 8.0 0.01 25.4 1-M 12/2/24 2.3 7.9 8.0 0.01 25.6 1-T 12/3/24 2.3 7.9 8.0 0.01 25.4 2.35*

26.80*

1-W 12/4/24 2.3 7.9 8.0 0.01 25.1 1-Th 12/5/24 2.3 7.9 8.0 0.01 24.4 1-F 12/6/24 2.3 7.9 8.0 0.01 24.2 1-Sa 12/7/24 2.3 7.9 8.0 0.01 25.0 2-Su 12/8/24 2.3 7.9 8.0 0.01 26.6 2-M 12/9/24 2.3 7.9 8.0 0.01 25.9 2-T 12/10/24 2.3 7.8 7.9 0.01 24.5 2-W 12/11/24 2.3 7.9 8.0 0.01 25.0 2-Th 12/12/24 2.3 7.8 8.1 0.01 24.7 2-F 12/13/24 2.3 7.8 7.9 0.01 24.9 2-Sa 12/14/24 2.3 7.8 8.0 0.00 26.9 3-Su 12/15/24 2.3 7.8 8.0 0.01 26.6 3-M 12/16/24 2.3 7.8 7.9 0.00 25.4 3-T 12/17/24 2.3 7.8 7.9 0.01 25.1 3-W 12/18/24 2.3 7.8 7.9 0.01 28.3 3-Th 12/19/24 2.3 7.8 7.9 0.01 26.7 3-F 12/20/24 2.3 7.8 8.0 0.01 25.7 3-Sa 12/21/24 2.3 7.8 7.9 0.01 26.3 4-Su 12/22/24 2.3 7.9 8.0 0.01 26.2 4-M 12/23/24 1.5 7.8 8.3 0

0.01

<0.1*

26.0 4-T 12/24/24 2.1 7.8 7.9 0.01 26.3 4-W 12/25/24 2.0 7.8 8.0 0.01 26.2 4-Th 12/26/24 1.8 7.8 8.0 0.01 28.9 4-F 12/27/24 1.7 7.9 8.0 0.02 27.7 4-Sa 12/28/24 1.7 7.9 8.0 0.02 27.7 5-Su 12/29/24 1.9 7.9 8.1 0.01 27.3 5-M 12/30/24 2.2 7.9 8.1 0.01 26.0 5-T 12/31/24 2.1 7.9 8.0 0.01 24.5 Daily Minimum 7.8 18.7

>= 6.5 (RO)

Report Only Average Monthly 2.2 2.35 26.8 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 2.3 8.3 0.02 28.9 2.35 26.8

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total 0

Report Only Report Only Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment RWTS All Parameters C

CWB Halogens, Total Combined, Total Residual Total Residual Milligrams/L (mg/L) 12/23/2024 Bl<0.1 Grab sample verification TRH <0.1 prior to restoring blowdown.

CWB Chromium Total Micrograms/L (ug/L) 12/3/2024 2.35 Results from 24-hour composite collected 12-2-24 to 12-3

-24.

CWB Zinc Total Micrograms/L (ug/L) 12/3/2024 26.80 Results from 24-hour composite collected 12-2-24 to 12-3

-24.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Monitoring Period:12/01/2024 - 12/31/2024 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: Intk - Cooling water intake structure Energy Northwest Columbia Generating Station Monitoring Point Week Intk 1-Su 12/1/24 20.3 1-M 12/2/24 20.3 1-T 12/3/24 20.3 1-W 12/4/24 20.0 1-Th 12/5/24 19.6 1-F 12/6/24 19.8 1-Sa 12/7/24 19.7 2-Su 12/8/24 21.0 2-M 12/9/24 12.4 2-T 12/10/24 15.7 2-W 12/11/24 19.7 2-Th 12/12/24 19.3 2-F 12/13/24 20.4 2-Sa 12/14/24 20.7 3-Su 12/15/24 21.2*

3-M 12/16/24 20.2*

3-T 12/17/24 20.3 3-W 12/18/24 22.6 3-Th 12/19/24 20.7 3-F 12/20/24 20.7 3-Sa 12/21/24 20.2 4-Su 12/22/24 20.4 4-M 12/23/24 19.8 4-T 12/24/24 20.0 4-W 12/25/24 20.7 4-Th 12/26/24 22.1 4-F 12/27/24 21.1 4-Sa 12/28/24 21.7 5-Su 12/29/24 21.4 5-M 12/30/24 21.0*

5-T 12/31/24 20.5*

Average Monthly 20.1 Report Only Monthly Total 623.8 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Outfall: Intk - Cooling water intake structure Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment Intk Flow MGD 12/15/2024 21.2 Partial flow measurement data for this day. Average calculated using data from 12/15/24 0000-1659 due to flow data unavailable.

Intk Flow MGD 12/16/2024 20.2 Partial flow measurement data for this day. Average calculated using data from 12/16/24 0600-2359 due to flow data unavailable.

Intk Flow MGD 12/30/2024 21.0 Partial flow measurement data for this day. Average calculated using data from 12/30/24 0000-1559 due to flow data unavailable.

Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Intk Flow MGD 12/31/2024 20.5 Partial flow measurement data for this day. Average calculated using data from 12/31/24 0700-2359 due to flow data unavailable.

I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Mary Joy Ramos Signature Date 1/15/2025 7:24:31 AM

 



   





 






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Scott A. Vance Vice President, Corporate Governance and General Counsel P.O. Box 968, MD PE13 Richland, WA 99352-0968 Ph. 509.377-4650 l F. 509.372.5330 savance@energy-northwest.com March 11, 2024 GO2-24-040 DIC 409.8 Amy Moon Siting and Compliance Lead Energy Facility Site Evaluation Council ELECTRONIC SUBMITTAL ONLY P.O. Box 43172 Olympia, WA 98504-3172

Subject:

MARCH 2024 COLUMBIA GENERATING STATION NPDES 5-DAY DISCHARGE NONCOMPLIANCE REPORT

Reference:

NPDES Permit No. WA002515-1, Conditions S3.F.2.b.iv & c.

Dear Ms. Moon:

In accordance with the referenced permit conditions, Energy Northwest is providing a National Pollutant Discharge Elimination System (NPDES) 5-day noncompliance report for the exceedance of the Total Residual Halogen (TRH) maximum daily discharge limit.

Energy Northwest completed a report within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> pursuant to NPDES permit condition S3.F.2.b.iv, which involved notification via telephone to the Energy Facility Site Evaluation Council (EFSEC) phone number listed on the NPDES permit. This notification occurred at approximately 2303 PST on March 6, 2024. Energy Northwest followed up by phone call with EFSEC the morning of March 7 to ensure the notification was received.

I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.

Respectfully,

Final Approver Scott A. Vance Vice President, Corporate Governance and General Counsel

Attachment:

NPDES Report Within Five Days - Total Residual Halogen Exceedance cc:

Ami Hafkemeyer, EFSEC Laura Fricke, Ecology Joseph Lippold, Ecology INTERNAL DISTRIBUTION:

FILE COPY Vance/lb Columbia Files 964Y Docket File PE20

GO2-24-040 Attachment 1 NPDES Report Within Five Days - Total Residual Halogen Exceedance

1. A description of the noncompliance and its cause.

At approximately 1635 PST on March 6, 2024, Energy Northwest discovered a malfunction in the halogenation/dehalogenation system at Columbia Generating Station, which is used for continuous control of the biological growth in the circulating water (CW) and plant service water (TSW) systems. Its also used to prevent discharge of halogens into the Columbia River during continuous blowdown.

This malfunction resulted in an exceedance of the maximum daily effluent limit of 0.1 milligrams/liter (mg/L) for total residual halogen (TRH) per Columbias National Pollutant Discharge Elimination System (NPDES) permit.

The automatic isolation function of the halogenation/dehalogenation system and the emergency trip push button failed to isolate the continuous blowdown line. Workers manually secured the system and isolated the continuous blowdown line to the Columbia River at approximately 1646 PST on March 6, 2024.

2. The period of noncompliance, including exact dates and times.

The period of noncompliance (e.g., exceedance of the maximum daily effluent limit for TRH) occurred on March 6, 2024. Maximum daily effluent limit is defined as being the highest allowable daily discharge. Per the NPDES permit Table 2 footnote b, the daily discharge is the average discharge of TRH measured during a calendar day. The average TRH discharge for the noncompliance period of March 6, 2024, was 1.06 mg/L.

Based on a review of continuous TRH data collected, TRH readings above the 0.1 mg/L maximum daily effluent limit for TRH began on March 6, 2024 at approximately 0815 PST and ended on March 6, 2024 at approximately 1646 PST (when blowdown to the Columbia River was isolated).

3. The estimated time the Permittee expects the noncompliance to continue if not yet corrected.

The noncompliance was terminated when blowdown (discharge to the Columbia River) was isolated at approximately 1646 PST on March 6, 2024. Blowdown was successfully restored on March 7, 2024, at approximately 1554 PST after collection and verification of TRH (i.e., less than 0.1 mg/L) via two grab samples taken 15 minutes apart.

4. Steps taken or planned to reduce, eliminate, and prevent recurrence of the noncompliance.

An evaluation of the halogenation/dehalogenation system malfunction is being driven by the station Corrective Action Program (CAP) utilizing the Condition Report (CR) process and is assigned CR number 456023. Chemistry and Information Services Departments are working with the equipment vendor to gain an understanding of and address the issues regarding the halogenation/dehalogenation system, aiming to prevent any future recurrence. The halogenation/dehalogenation system will remain inoperable until Energy Northwest has a clear understanding of the issue and has implemented appropriate fixes.

5. If the noncompliance involves an overflow prior to the treatment works, an estimated of the quantity (in gallons) of untreated overflow.

This noncompliance does not involve an overflow prior to the treatment works.

GO2-24-085 Attachment 1 Columbia Generating Station NPDES 5-Day Noncompliance Report

1. A description of the noncompliance and its cause.

On September 10, 2024, at approximately 2:35 PM, Environmental and Regulatory Programs was notified that no more than 30 gallons of silicone compressor fluid, Sullair 24KT, had potentially leaked through the service air compressor (SA-C-1) heat exchanger (SA-HX-2) and entered the Plant Service Water (TSW) system.

SA-C-1 was removed from service on September 3rd due to excessive oil consumption. Despite the lowered oil level, the best information at the time indicated no loss of oil to the TSW had occurred. The heat exchanger remained out of service and was pressure tested on September 10 and confirmed to have a leak that would allow the silicone compressor fluid to migrate into TSW.

TSW cools the service air compressor and other non-radioactive loads in the facility before returning to the Circulating Water (CW) basin, where it is mixed with circulating water and may enter a system again such as TSW, CW, or Fire Protection (FP) water. Because TSW returns to the CW basin, it can be discharged to the Columbia River with circulating water blowdown.

2. The period of noncompliance, including exact dates and times.

On September 2, 2024, at 5:18 PM the oil level in the system was noted as being low but within specification. On September 3, 2024, at 12:43 PM the system was secured (removed from service) and any potential for additional release of oil to TSW was eliminated.

3. The estimated time the Permittee expects the noncompliance to continue if not yet corrected.

The condition leading to the potential noncompliance has been corrected. The leak is not ongoing and was stopped at approximately 12:43 PM on September 3rd.

4. Steps taken or planned to reduce, eliminate, and prevent recurrence of the noncompliance.

An investigation is being conducted into what caused the failure of the heat exchanger. All damaged heat exchanger equipment was replaced and tested before the air compressor was returned to service. The evaluation is being driven by the Energy Northwest Corrective Action Program (CAP) and is assigned Condition Report number 461715.

5. If the noncompliance involves an overflow prior to the treatment works, an estimated of the quantity (in gallons) of untreated overflow.

This noncompliance does not involve an overflow prior to the treatment works.