ML24060A102

NRR E-mail Capture - (External_Sender) Energy Northwest Columbia Generating Station 2023 Biological Monitoring Report

ML24060A102
Person / Time
Site:	Columbia  (NPF-21)
Issue date:	02/28/2024
From:	Energy Northwest
To:	Arlene B Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
Download: ML24060A102 (143)

Text

From:

Mehinagic, Denis <dmehinagic@energy-northwest.com>

Sent:

Wednesday, February 28, 2024 4:34 PM To:

ritchie.graves@noaa.gov Cc:

Briana Arlene; EndangeredSpecies Resource; Ramos, Mary Joy.; Hildman, Cynthia M.; Pierson, Amanda M.

Subject:

[External_Sender] Energy Northwest Columbia Generating Station 2023 Biological Monitoring Report Attachments:

GO2-24-028 Energy Northwest Columbia Generating Station 2023 Biological Monitoring Report.pdf Mr. Graves, Please find attached the 2023 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.

The Biological Monitoring Report contains a post-season report describing biological monitoring activities and a summary of any plant changes that affect effluent discharge.

It also contains a copy of all National Pollutant Discharge Elimination System (NPDES) submissions that were transmitted to EFSEC in the year.

Denis Mehinagic, M.S.

Environmental & Regulatory Programs Lead Energy Northwest 509-372-5768 l dmehinagic@energy-northwest.com

Hearing Identifier:

NRR_DRMA Email Number:

2415 Mail Envelope Properties (CO6PR09MB7704B8002C53DACD939E4286EF582)

Subject:

[External_Sender] Energy Northwest Columbia Generating Station 2023 Biological Monitoring Report Sent Date:

2/28/2024 4:33:49 PM Received Date:

2/28/2024 4:34:19 PM From:

Mehinagic, Denis Created By:

dmehinagic@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 "Hildman, Cynthia M." <cmhildman@energy-northwest.com>

Tracking Status: None "Pierson, Amanda M." <ampierson@energy-northwest.com>

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

Tracking Status: None Post Office:

CO6PR09MB7704.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 832 2/28/2024 4:34:19 PM GO2-24-028 Energy Northwest Columbia Generating Station 2023 Biological Monitoring Report.pdf 4599030 Options Priority:

Normal Return Notification:

No Reply Requested:

No Sensitivity:

Normal Expiration Date:

Mary Joy C. Ramos Columbia Generating Station P.O. Box 968, MD PE03 Richland, WA 99352-0968 Ph. 509-377-8534 mjoyramos@energy-northwest.com February 28th, 2024 GO2-24-028 DIC 404.1 Ritchie Graves Branch Chief Columbia Hydropower National Marine Fisheries Service ELECTRONIC SUBMITTAL ONLY 1201 NE Lloyd Blvd, Suite 1100 Portland, OR 97232

Subject:

2023 BIOLOGICAL MONITORING REPORT

Reference:

Letter, GI2-17-061, March 10, 2017, from Barry A. Thorn (National Marine Fisheries Service) to Jeffery J. Rikhoff (Division of License Renewal, Office of Nuclear Regulation) Endangered Species Act Section 7(a)(2) Biological Opinion, and Magnusion-Stevens Fishery Conservation and Management Act Essential Fish Habitat Response for Renewing the Operating License for the Columbia Generating Station, Washington, Condition 2.9.4(4)(a).

Condition 2.9.4(4)(a) of the Endangered Species Act 7(a)(2) Biological Opinion requires Energy Northwest to submit an annual summary of biological monitoring data and reports submitted pursuant to National Pollutant Discharge Elimination System (NPDES) Permit WA0025151. Attached is the 2023 Biological Monitoring Report, which consists of the Post Season Fish Collection Report, 2023 NPDES Permit Discharge Monitoring Reports (DMRs),

and Whole Effluent Toxicity (WET) Reports.

Respectfully, Signed By:

Ramos, Mary Joy. - DOMAIN1\mramos 2/28/2024 1:06 PM Final Approver Mary Joy C. Ramos Environmental and Regulatory Programs Manager

Enclosure:

2023 Post Season Fish Collection Report 2023 NPDES DMRs

2023 NPDES WET Reports cc: Briana.Grange@nrc.gov EndangeredSpecies.Resource@nrc.gov INTERNAL DISTRIBUTION:

FILE COPY Document Control APW Docket File PE20

Prepared by Energy Northwest Environmental Services, February 2024 Energy Northwest Columbia Generating Station 2023 Post Season Fish Collection Report The purpose of this report is to document fish collection activities on the part of Energy Northwest (EN) during the 2023 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 March 10, 2017.

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 the Columbia Generating Station.

Resident Species Collection Columbia River The requirement for resident fish species collected from the Columbia River was satisfied with the capture of two smallmouth bass.

EN personnel collected two small mouth bass on 11/16/2023 from shoreline near CGS and TMU pumphouse. GPS coordinates were recorded as 46.472584°, -119.265403°, water temperature at 11.9 degrees Celsius. The fish was caught using hook and line techniques that targeted bass. Fishing techniques used to collect the resident species were in accordance with the Washington Dept. of Fish and Wildlife (WDFW) freshwater fishing rules for the resident species of interest.

At least six attempts to catch resident fish from the Columbia River were made. The small mouth bass were the only resident fish collected for 2023.

Snake River No resident fish from the Snake River were obtained by local fisherman this year. Snake river samples are used for control samples.

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 8/2/2023.

One Chinook Salmon from Ringold Springs Hatchery was collected by hatchery personnel on 10/11/2023. The location is at Station 46.513°, -119.259° and the water temperature was 19.3 degrees Celsius. A net was used to retrieve the Salmon.

Prepared by Energy Northwest Environmental Services, February 2024 A Chinook Salmon was provided by Snake River Lyons Ferry Hatchery on 10/19/2023, GPS coordinates 46.599639°, -

118.229556° and the river temperature was 19.0 degrees Celsius. The salmon was caught by net using hatchery personnel.

Fish Collection Summary Reasonable and prudent measures were utilized to minimize the impact of biological monitoring activities during 2023.

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.

Offsite Dose Calculation Manual (ODCM) table 6.3.1-1 4B specifies collection of three fish species in the vicinity of the plant discharge and collection the same three species at a control location not influenced by plant discharge (usually the SNAKE river). Energy Facility Site Evaluation Council (EFSEC) Resolution 332 Monitoring Program A. Program Elements Section 4, Section C. Sample Types and Media - General Discussion #10, Table 1 discusses sampling requirements for one sample from 3 species one anadromous and two resident in the vicinity of the plant discharge area and one sample from the same or similar species from areas not influenced by plant discharge. The Radiological Environmental Monitoring Program (REMP) is dependent on fish donations from local fisherman as it is illegal to purchase fish from local fisherman.

There were two chinook donations one from the CGS discharge area and one donation from the snake river. One type of resident fish (smallmouth bass) was donated which came from the plant discharge area. We did not obtain 3 fish species from the plant discharge area, only two were obtained. W also did not obtain three species from a control location, only one was obtained. Several hours were dedicated by REMP program individuals in attempts to capture fish using rod and hook method without success. Electroshock methods cannot be employed by CGS due to concerns about possibly violating Federal endangered species act regulations.

Summary of Changes to CGS Aqueous Effluent Discharges During the 2023 calendar year, the National Pollutant Discharge Elimination System (NPDES) effluent monitoring as reported on the monthly discharge monitoring reports indicated that all parameters were within permit specifications with no issues or violations. Additionally, whole effluent toxicity testing performed in the first and second quarter of 2023 showed no statistically significant difference in survival between the control and the acute critical effluent concentration (ACEC, 11% effluent). Under the new NPDES permit effective July 1, 2023, quarterly whole effluent toxicity testing is not required and was not performed in the third and fourth quarters of 2023. Continuous halogenation of circulating water with dehalogenation of the blowdown water was implemented on November 6, 2019. This process involves the discharge of additional dehalogenation chemicals as approved by an amendment to the CGS NPDES permit dated 3/19/2019. Implementation of this process has not resulted in any permit violations to date.

Mary Joy C. Ramos Columbia Generating Station P.O. Box 968, MD PE03 Richland, WA 99352-0968 Ph. 509-377-8534 mjoyramos@energy-northwest.com February 28, 2024 GO2-24-021 DIC 409 Amy Moon Siting and Compliance Lead Energy Facility Site Evaluation Council ELECTRONIC SUBMITTAL ONLY PO Box 43172 Olympia, WA 98504-3172

Subject:

2023 ANNUAL FISH COLLECTION REPORT

Reference:

Letter dated April 23, 2021 GI2-21-044 Columbia Generating Station, Energy Northwest Resolution 347, Amendment No. 1 (Authorizing Fish for REMP)

Pursuant to the requirements of Energy Facility Site Evaluation Council (EFSEC) Resolution 347, Section (8) a - e, please see the attached annual report on fish collection activities at Columbia Generating Station (CGS) for 2023. Per the resolution, the report was completed on the EFSEC-provided Resolution 347 Annual Report Form.

If you have any questions about this report, please contact Denis Mehinagic (509) 372-5768.

Respectfully, Signed By:

Ramos, Mary Joy. - DOMAIN1\mramos 2/28/2024 9:21 AM Final Approver Mary Joy C. Ramos Environmental and Regulatory Programs Manager

Enclosure:

2023 Fish Collection Report cc: peggy.miller@dfw.wa.gov Paul.Hoffarth@dfw.wa.gov Bruce.Baker@dfw.wa.gov

INTERNAL DISTRIBUTION:

FILE COPY Document Control APW Docket File PE20

ENERGY FACILITY SITE EVALUATION and WASHINGTON DEPARTMENT OF FISH & WILDLIFE RESOLUTION 347 ANNUAL REPORT FORM Please submit this report at the end of the permit period:

Project Start Date EFSEC WDFW Permittee Name ATTN: AMY MOON ATTN: LICENSING DIVISION Agency/Institution 6/30/2023 Mary Ramos Energy Northwest PO Box 43172 EMAIL: peggy.miller@dfw.wa.gov email address ampierson@energy-northwOlympia, WA 98504-3172 Paul.Hoffarth@dfw.wa.gov Permit No.

Resolution 347 EMAIL: amy.moon@utc.wa.gov Bruce.Baker@dfw.wa.gov PHONE: 360-664-1362 PHONE: 360-902-2464, option 4

• 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 10/11/2023 Chinook Salmon (Oncorhynchus tshawytscha)

J H

1 Columbia River Ringold Springs Hatchery 46.513°, -119.259° 12 Donated by Hatchery N

Tissue collected - fillet 10/19/2023 Chinook Salmon (Oncorhynchus tshawytscha)

A H

1 Snake River Lyons Ferry Hatchery 46.599639°, -118.229556° 12 Donated by Hatchery N

Tissue collected - fillet 11/16/2023 Smallmouth bass (Micropterus dolomieu) 2 Columbia River near CGS TMU pumphouse 46.472584°, -119.265403° 12 Hook and line fishing 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.

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-024 DIC: 1316.20 DATE:

February 14, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station January 2023 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 2023.

All monitoring parameters were within permit specifications for the month. Because of equipment issues, a temporary tanker truck continues to be used for sulfuric acid additions to the circulating water system to control the pH. This method results in greater variation of the blowdown pH than is typical.

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 Marshall Schmitt at (509) 372-5334.

Attachment:

NPDES Discharge Monitoring Report, January 2023 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

M Schmitt (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 February 14, 2023 January 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Marshall Schmitt, Environmental Scientist, E&RP Reviewed by: Devon Van Alyne, Manager, Laboratory Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Monitoring Period:01/01/2023 - 01/31/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Energy Northwest Columbia Generating Station Monitoring Point Week CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB2 1-Su 1/1/23 2.7 7.8 8.1 25.8 0.00 1-M 1/2/23 2.7 7.8 7.9 26.0 0.00 1-T 1/3/23 2.7 7.8 8.1 26.1 0.00 1-W 1/4/23 2.7 7.7 7.9 26.5 4.3*

19.9*

2.3*

16.9*

0.00 1-Th 1/5/23 2.7 7.7 8.1 27.6 0.00 1-F 1/6/23 2.7 7.7 8.0 26.0 0.00 1-Sa 1/7/23 2.7 7.8 8.0 26.3 0.00 2-Su 1/8/23 2.7 7.8 8.0 26.9 0.00 2-M 1/9/23 2.7 7.8 8.1 27.3 0.00 2-T 1/10/23 2.7 7.8 8.0 27.2 0.00 2-W 1/11/23 2.7 7.8 8.0 27.1 0.00 2-Th 1/12/23 2.4 7.7 8.1 27.0 0.00 2-F 1/13/23 2.4 7.6 7.9 24.3 0.06 2-Sa 1/14/23 2.6 7.8 8.0 27.3 0.00 3-Su 1/15/23 2.7 7.8 8.1 27.5 0.00 3-M 1/16/23 2.6 7.9 8.0 27.1 0.00 3-T 1/17/23 2.7 7.8 7.9 26.4 0.00 3-W 1/18/23 2.7 7.6 7.9 25.7 0.00 3-Th 1/19/23 2.7 7.6 7.9 26.0 0.00 3-F 1/20/23 2.7 7.6 8.1 25.5 0.00 3-Sa 1/21/23 2.7 7.6 7.9 25.0 0.00 4-Su 1/22/23 2.7 7.8 7.9 24.9 0.00 4-M 1/23/23 2.7 7.8 7.9 25.3 0.00 4-T 1/24/23 2.7 7.7 7.8 25.0 0.00 4-W 1/25/23 2.7 7.6 7.8 25.3 0.00 4-Th 1/26/23 2.7 7.5 7.9 25.0 0.00 4-F 1/27/23 2.7 7.8 8.1 27.4 0.00 4-Sa 1/28/23 2.7 7.6 7.9 27.1 0.00 5-Su 1/29/23 2.7 7.9 8.1 30.1 0.00 5-M 1/30/23 2.7 7.6 7.9 28.4 0.00 5-T 1/31/23 2.7 7.6 8.1 M

26.9 M

0.00 Instantaneous Minimum 7.5

>= 6.5 (RO)

Average Monthly 2.7 2.3 16.9

<= 5.6

<= 8.2

<= 53 Instantaneous Maximum 8.1

<= 9.0 (RO)

Monthly Total M

<= 446 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: 1 of 5

Monitoring Point Week CWB2 SSWD SSWD 1-Su 1/1/23 1-M 1/2/23 1-T 1/3/23 1-W 1/4/23 1-Th 1/5/23 1-F 1/6/23 1-Sa 1/7/23 2-Su 1/8/23 2-M 1/9/23 2-T 1/10/23 2-W 1/11/23 2-Th 1/12/23 2-F 1/13/23 2-Sa 1/14/23 3-Su 1/15/23 3-M 1/16/23 3-T 1/17/23 3-W 1/18/23 3-Th 1/19/23 3-F 1/20/23 3-Sa 1/21/23 4-Su 1/22/23 4-M 1/23/23 4-T 1/24/23 4-W 1/25/23 4-Th 1/26/23 4-F 1/27/23 4-Sa 1/28/23 5-Su 1/29/23 5-M 1/30/23 5-T 1/31/23 M

Instantaneous Minimum Average Monthly Instantaneous Maximum Monthly Total Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 5

Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment CWB Turbidity (Nephelometric)

Measured NTU 1/4/2023 4.3 Results from grab sample collected 1/4/23 CWB Copper Total Micrograms/L (ug/L) 1/4/2023 19.9 Results from a 24-hr composite sample collected 1/3/23-1/4/23 CWB Chromium Total Micrograms/L (ug/L) 1/4/2023 2.3 Results from a 24-hr composite sample collected 1/3/23-1/4/23 CWB Zinc Total Micrograms/L (ug/L) 1/4/2023 16.9 Results from a 24-hr composite sample collected 1/3/23-1/4/23 CWB2 All Parameters Maximum daily total residual halogen from continuous TRH analyzer reported.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 5

Monitoring Period:01/01/2023 - 01/31/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 002 Energy Northwest Columbia Generating Station Monitoring Point Week Pnd 1-Su 1/1/23 42465 1-M 1/2/23 42365 1-T 1/3/23 57765 1-W 1/4/23 27265 1-Th 1/5/23 53565 1-F 1/6/23 27265 1-Sa 1/7/23 40465 2-Su 1/8/23 40265 2-M 1/9/23 40365 2-T 1/10/23 69365 2-W 1/11/23 27265 2-Th 1/12/23 52765 2-F 1/13/23 39565 2-Sa 1/14/23 52065 3-Su 1/15/23 39465 3-M 1/16/23 39465 3-T 1/17/23 52265 3-W 1/18/23 39365 3-Th 1/19/23 27265 3-F 1/20/23 40865 3-Sa 1/21/23 38465 4-Su 1/22/23 39865 4-M 1/23/23 27265 4-T 1/24/23 39665 4-W 1/25/23 27265 4-Th 1/26/23 64865 4-F 1/27/23 27265 4-Sa 1/28/23 27265 5-Su 1/29/23 39965 5-M 1/30/23 27265 5-T 1/31/23 39665 Monthly Total 1250315 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: 4 of 5

Monitoring Period:01/01/2023 - 01/31/2023 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 1/1/23 19.9 1-M 1/2/23 20.1 1-T 1/3/23 20.3 1-W 1/4/23 20.3 1-Th 1/5/23 21.1 1-F 1/6/23 20.5 1-Sa 1/7/23 20.6 2-Su 1/8/23 21.0 2-M 1/9/23 20.9 2-T 1/10/23 20.7 2-W 1/11/23 18.3 2-Th 1/12/23 11.2 2-F 1/13/23 13.1 2-Sa 1/14/23 20.2 3-Su 1/15/23 21.3 3-M 1/16/23 22.1 3-T 1/17/23 20.2 3-W 1/18/23 20.4 3-Th 1/19/23 21.4 3-F 1/20/23 20.4 3-Sa 1/21/23 20.3 4-Su 1/22/23 20.2 4-M 1/23/23 20.3 4-T 1/24/23 20.2 4-W 1/25/23 20.3 4-Th 1/26/23 20.3 4-F 1/27/23 23.2 4-Sa 1/28/23 20.8 5-Su 1/29/23 20.0 5-M 1/30/23 20.1 5-T 1/31/23 20.0 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 2/14/2023 8:44:29 AM Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 5 of 5

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-037 DIC: 1316.20 DATE:

March 14, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station February 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the National Pollutant Discharge Elimination System (NPDES)

Discharge Monitoring Report (DMR) for February 2023. All monitoring parameters were within permit specifications for the month. Because of equipment issues, a temporary tanker truck continues to be used for sulfuric acid additions to the circulating water system to control the pH. This method results in greater variation of the blowdown pH than is typical.

On February 21, 2023 Potable Water Cold Flow Indicator 6 (PWC-FI-6) was found to have exceeded the allowable annual calibration window due to an incorrect retirement of the recurring Preventative Maintenance (PM) task. See Condition Report (CR) 441818.

NPDES permit section S2.C.5. states: Calibrate flow-monitoring devices at a minimum frequency of at least one calibration per year and the last calibration of the instrument was on November 19, 2021 under WO 02158845. Therefore, the NPDES required calibration frequency of once per year was exceeded when the instrument was not calibrated in 2022.

PWC-FI-6 was calibrated on March 2, 2023 and the as-found condition of the flowmeter was within calibration tolerance. No adjustment was required. The exceeded annual calibration is reportable under S3.E.e of the NPDES permit and is to be submitted with the February 2023 DMR.

Energy Northwest provided an informal notice to the Energy Facility Site Evaluation Council (EFSEC) of this event on February 28, 2023 during a scheduled phone call.

EFSEC requested the noncompliance report also be transmitted to them directly in addition to the submission on WQWebPortal.

Columbia Generating Station Page 2 of 2 March 14, 2023 February 2023 DMR The report will be submitted electronically to the State of Washington Department of Ecology (Ecology) via Ecologys online reporting system. The report required by NPDES permit section S3.E.e will be transmitted electronically to Amy Moon, Siting and Compliance Lead at the Energy Facility Site Evaluation Council. If you have any questions concerning this information, please contact Marshall Schmitt at (509) 372-5334.

Attachments: NPDES Discharge Monitoring Report, February 2023 Noncompliance Report PWC-FI-6 Calibration KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

M Schmitt (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, Environmental Technician, Environmental Services Reviewed by: Marshall Schmitt, Environmental Scientist, E&RP Reviewed by: Matthew Turner, Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Monitoring Period:02/01/2023 - 02/28/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Energy Northwest Columbia Generating Station Monitoring Point Week CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB2 1-W 2/1/23 2.7 7.9 8.0 26.7 0.00 1-Th 2/2/23 2.7 7.9 8.0 25.7 0.00 1-F 2/3/23 2.7 7.9 8.1 26.4 0.00 1-Sa 2/4/23 2.7 8.0 8.1 26.6 0.00 2-Su 2/5/23 2.7 8.1 8.1 25.8 0.00 2-M 2/6/23 2.7 8.1 8.3 26.3 0.00 2-T 2/7/23 2.6 8.1 8.3 27.6 3.4*

10.5*

<1*

12*

0.00 2-W 2/8/23 2.6 7.9 8.2 27.6 0.01 2-Th 2/9/23 2.7 7.8 8.1 26.3 0.00 2-F 2/10/23 2.7 7.9 8.0 26.1 0.00 2-Sa 2/11/23 2.7 7.9 8.0 26.1 0.00 3-Su 2/12/23 2.6 7.9 8.1 26.4 0.00 3-M 2/13/23 2.6 7.9 8.1 27.2 0.00 3-T 2/14/23 2.6 7.7 8.1 26.6 0.00 3-W 2/15/23 2.7 7.7 8.1 25.9 0.00 3-Th 2/16/23 2.7 7.9 8.0 25.2 0.00 3-F 2/17/23 2.7 7.7 8.1 26.5 0.00 3-Sa 2/18/23 2.7 7.9 8.1 27.2 0.00 4-Su 2/19/23 2.7 7.9 8.1 27.9 0.00 4-M 2/20/23 2.6 8.0 8.1 29.4 0.00 4-T 2/21/23 2.6 7.9 8.2 30.0 0.00 4-W 2/22/23 2.7 7.6 8.0 27.1 0.00 4-Th 2/23/23 2.7 7.7 7.9 29.2 0.00 4-F 2/24/23 2.7 7.7 8.0 29.0 0.00 4-Sa 2/25/23 2.7 7.9 8.2 28.5 0.00 5-Su 2/26/23 2.7 7.9 8.2 27.9 0.00 5-M 2/27/23 2.7 7.9 8.0 27.1 0.00 5-T 2/28/23 2.7 7.7 8.0 M

26.6 M

0.00 Instantaneous Minimum 7.6

>= 6.5 (RO)

Average Monthly 2.7

<1 12

<= 5.6

<= 8.2

<= 53 Instantaneous Maximum 8.3

<= 9.0 (RO)

Monthly Total M

<= 446 Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1 Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 5

Monitoring Point Week CWB2 SSWD SSWD 1-W 2/1/23 1-Th 2/2/23 1-F 2/3/23 1-Sa 2/4/23 2-Su 2/5/23 2-M 2/6/23 2-T 2/7/23 2-W 2/8/23 2-Th 2/9/23 2-F 2/10/23 2-Sa 2/11/23 3-Su 2/12/23 3-M 2/13/23 3-T 2/14/23 3-W 2/15/23 3-Th 2/16/23 3-F 2/17/23 3-Sa 2/18/23 4-Su 2/19/23 4-M 2/20/23 4-T 2/21/23 4-W 2/22/23 4-Th 2/23/23 4-F 2/24/23 4-Sa 2/25/23 5-Su 2/26/23 5-M 2/27/23 5-T 2/28/23 M

Instantaneous Minimum Average Monthly Instantaneous Maximum Monthly Total Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 5

Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment CWB Turbidity (Nephelometric)

Measured NTU 2/7/2023 3.4 Results from grab sample collected 2/7/23 CWB Copper Total Micrograms/L (ug/L) 2/7/2023 10.5 Results from a 24-hr composite sample collected 2/6/23-2/7/23 CWB Chromium Total Micrograms/L (ug/L) 2/7/2023 Bl<1 Results from a 24-hr composite sample collected 2/6/23-2/7/23 CWB Zinc Total Micrograms/L (ug/L) 2/7/2023 12 Results from a 24-hr composite sample collected 2/6/23-2/7/23 CWB2 All Parameters Maximum daily total residual halogen from continuous TRH analyzer reported.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 5

Monitoring Period:02/01/2023 - 02/28/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 002 Energy Northwest Columbia Generating Station Monitoring Point Week Pnd 1-W 2/1/23 26178 1-Th 2/2/23 38778 1-F 2/3/23 38778 1-Sa 2/4/23 26178 2-Su 2/5/23 50978 2-M 2/6/23 38778 2-T 2/7/23 26178 2-W 2/8/23 38478 2-Th 2/9/23 26178 2-F 2/10/23 63878 2-Sa 2/11/23 38778 3-Su 2/12/23 38478 3-M 2/13/23 38678 3-T 2/14/23 38678 3-W 2/15/23 26178 3-Th 2/16/23 38778 3-F 2/17/23 26178 3-Sa 2/18/23 48578 4-Su 2/19/23 38578 4-M 2/20/23 26178 4-T 2/21/23 26178 4-W 2/22/23 38578 4-Th 2/23/23 38778 4-F 2/24/23 38878 4-Sa 2/25/23 38578 5-Su 2/26/23 38578 5-M 2/27/23 38478 5-T 2/28/23 38378 Monthly Total 1029884 Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge, M - Monitoring Is Conditional/Not Req This MP Version: 1 Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 5

Monitoring Period:02/01/2023 - 02/28/2023 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 2/1/23 19.9 1-Th 2/2/23 20.1 1-F 2/3/23 20.0 1-Sa 2/4/23 22.5 2-Su 2/5/23 21.5 2-M 2/6/23 22.2 2-T 2/7/23 22.2 2-W 2/8/23 22.0 2-Th 2/9/23 21.3 2-F 2/10/23 21.3 2-Sa 2/11/23 21.2 3-Su 2/12/23 21.4 3-M 2/13/23 22.5 3-T 2/14/23 22.1 3-W 2/15/23 21.4 3-Th 2/16/23 20.8 3-F 2/17/23 22.1 3-Sa 2/18/23 21.8 4-Su 2/19/23 22.6 4-M 2/20/23 23.4 4-T 2/21/23 23.1 4-W 2/22/23 20.7 4-Th 2/23/23 20.6 4-F 2/24/23 20.2 4-Sa 2/25/23 20.5 5-Su 2/26/23 20.6 5-M 2/27/23 19.8 5-T 2/28/23 21.1 Reporting Codes Used: B - Below Detection Limit/No Detection, 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 3/14/2023 3:21:44 PM Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 5 of 5

1 National Pollutant Discharge Elimination System Noncompliance Report A description of the noncompliance and its cause Columbia Generating Station (Columbia), operated by Energy Northwest, maintains a National Pollutant Discharge Elimination System (NPDES) wastewater discharge permit (No. WA002515-1) issued by the Washington State Energy Facility Site Evaluation Council (EFSEC). The NPDES permit authorizes the discharge of treated wastewater at permitted locations and establishes specific discharge limits. Per NPDES WA002515-1 S2.A(4) Columbia is required to monitor influent flows to the Evaporation Ponds and per S2.C.5 flow monitoring devices are required to be calibrated at least once per year.

On February 21, 2023, the Maintenance Services department discovered that the Preventative Maintenance (PM) task for annual calibration of PWC-FI-6, flowmeter for flocculator backwash to Evaporation Ponds 1 and 2, was inadvertently retired in a recent optimization effort. The PM was not approved for retirement during the optimization, but due to an error in verifying the proposed changes, it was retired anyway. Environmental and Regulatory Programs (E&RP) was notified at approximately 12:42 PM on the same day.

Based on the previous calibration work order (WO), WO 02158845, the internal annual calibration of PWC-FI-6 expired on November 19, 2022. NPDES permit section S2.C.5. states: Calibrate flow-monitoring devices at a minimum frequency of at least one calibration per year and the last calibration of the instrument was on November 19, 2021 under WO 02158845. Therefore, the NPDES required calibration frequency of once per year was exceeded when the instrument was not calibrated in 2022.

The PM was immediately reactivated and a new WO created. PWC-FI-6 was calibrated on March 2, 2023 under WO 02204506 and the flowmeter as-found was within tolerance. No calibration nor adjustment was required.

Energy Northwest provided an informal notice to EFSEC of this event on February 28, 2023 during a scheduled phone call. EFSEC requested the noncompliance report also be transmitted directly to the Siting and Compliance Lead in addition to the submission on WQWebPortal.

The period of noncompliance, including exact dates and times The period of noncompliance was from December 31, 2022 11:59 PM to March 2, 2023 12:47 AM.

The estimated time the Permittee expects the noncompliance to continue if not yet corrected N/A; The noncompliance was corrected on March 2, 2023.

Steps taken or planned to reduce, eliminate, and prevent recurrence of the noncompliance The annual PM was reinstated and a review of all recently retired PMs for potential impacts to permit compliance is in progress. To date, no additional impacts have been identified. Evaluation of additional actions to prevent recurrence of human performance errors is in progress.

2 If the noncompliance involves an overflow prior to the treatment works, an estimate of the quantity (in gallons) of untreated overflow This noncompliance did not involve an overflow.

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-051 DIC: 1316.20 DATE:

April 13, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Ashley Mowery, Environmental Technician (1025)

SUBJECT:

Columbia Generating Station March 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the National Pollutant Discharge Elimination System (NPDES)

Discharge Monitoring Report (DMR) for March 2023. All monitoring parameters were within permit specifications for the month. Because of equipment issues, a temporary tanker truck continues to be used for sulfuric acid additions to the circulating water system to control the pH. This method results in greater variation of the blowdown pH than is typical.

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 Marshall Schmitt at (509) 372-5334.

Attachments: NPDES Discharge Monitoring Report, March 2023 AJM DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

M Schmitt (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 April 13, 2023 March 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Marshall Schmitt, Environmental Scientist, E&RP Reviewed by: Matthew Turner, Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

Monitoring Period:03/01/2023 - 03/31/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Energy Northwest Columbia Generating Station Monitoring Point Week CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB2 1-W 3/1/23 2.7 7.7 8.0 27.3 0.00 1-Th 3/2/23 1.4 7.8 7.9 26.2 0.00 1-F 3/3/23 1.8 7.8 8.0 0

27.2

<0.1 0.02 1-Sa 3/4/23 2.8 7.9 8.1 26.4 0.02 2-Su 3/5/23 2.8 7.9 8.1 26.6 0.01 2-M 3/6/23 2.8 7.6 7.9 26.5 0.01 2-T 3/7/23 2.8 7.6 7.9 28.1 3.6*

12.0*

1.22*

14.4*

0.01 2-W 3/8/23 2.8 7.8 7.9 28.6 0.02 2-Th 3/9/23 2.8 7.6 7.9 29.5 0.02 2-F 3/10/23 2.8 7.7 8.0 29.7 0.03 2-Sa 3/11/23 2.8 7.6 7.7 27.9 0.02 3-Su 3/12/23 2.8 7.6 7.7 28.1 0.02 3-M 3/13/23 2.7 7.6 7.9 30.4 0.02 3-T 3/14/23 2.7 7.7 8.0 28.8 0.00 3-W 3/15/23 2.7 7.7 8.0 30.0 0.00 3-Th 3/16/23 2.7 7.8 8.1 29.9 0.00 3-F 3/17/23 2.7 7.7 8.0 28.9 0.01 3-Sa 3/18/23 2.7 7.9 8.1 27.2 0.01 4-Su 3/19/23 2.7 8.0 8.1 27.2 0.02 4-M 3/20/23 2.7 8.1 8.2 27.6 0.01 4-T 3/21/23 2.7 8.1 8.2 26.3 0.02 4-W 3/22/23 2.7 8.0 8.2 26.0 0.01 4-Th 3/23/23 2.7 8.0 8.1 27.2 0.01 4-F 3/24/23 2.7 8.1 8.1 26.9 0.00 4-Sa 3/25/23 2.7 8.0 8.1 24.3 0.00 5-Su 3/26/23 2.7 8.0 8.1 24.6 0.01 5-M 3/27/23 2.7 8.0 8.1 23.9 0.01 5-T 3/28/23 2.7 8.0 8.1 27.3 0.00 5-W 3/29/23 2.7 8.0 8.1 25.5 0.00 5-Th 3/30/23 0.6 8.0 8.0 0

24.5

<0.1 0.00 5-F 3/31/23 1.5 7.8 8.0 25.4 0.08 Instantaneous Minimum 7.6

>= 6.5 (RO)

Average Monthly 2.6 1.22 14.4

<= 5.6

<= 8.2

<= 53 Instantaneous Maximum 8.2

<= 9.0 (RO)

Monthly Total 0

<= 446 Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1 Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 5

Monitoring Point Week CWB2 SSWD SSWD 1-W 3/1/23 1-Th 3/2/23 1-F 3/3/23

<0.1 1-Sa 3/4/23 2-Su 3/5/23 2-M 3/6/23 2-T 3/7/23 2-W 3/8/23 2-Th 3/9/23 2-F 3/10/23 2-Sa 3/11/23 3-Su 3/12/23 3-M 3/13/23 3-T 3/14/23 3-W 3/15/23 3-Th 3/16/23 3-F 3/17/23 3-Sa 3/18/23 4-Su 3/19/23 4-M 3/20/23 4-T 3/21/23 4-W 3/22/23 4-Th 3/23/23 4-F 3/24/23 4-Sa 3/25/23 5-Su 3/26/23 5-M 3/27/23 5-T 3/28/23 5-W 3/29/23 5-Th 3/30/23

<0.1 5-F 3/31/23 Instantaneous Minimum Average Monthly Instantaneous Maximum Monthly Total Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 5

Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment CWB Turbidity (Nephelometric)

Measured NTU 3/7/2023 3.6 Results from grab sample collected 3/7/2023 CWB Copper Total Micrograms/L (ug/L) 3/7/2023 12.0 Results from a 24-hr composite sample collected 3/6/2023-3/7/2023 CWB Chromium Total Micrograms/L (ug/L) 3/7/2023 1.22 Results from a 24-hr composite sample collected 3/6/2023-3/7/2023 CWB Zinc Total Micrograms/L (ug/L) 3/7/2023 14.4 Results from a 24-hr composite sample collected 3/6/2023-3/7/2023 CWB2 All Parameters Maximum daily total residual halogen from continuous TRH analyzer reported.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 5

Monitoring Period:03/01/2023 - 03/31/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 002 Energy Northwest Columbia Generating Station Monitoring Point Week Pnd 1-W 3/1/23 37073 1-Th 3/2/23 43273 1-F 3/3/23 37073 1-Sa 3/4/23 24573 2-Su 3/5/23 36973 2-M 3/6/23 24573 2-T 3/7/23 24573 2-W 3/8/23 37273 2-Th 3/9/23 24573 2-F 3/10/23 37273 2-Sa 3/11/23 36773 3-Su 3/12/23 24573 3-M 3/13/23 37073 3-T 3/14/23 37073 3-W 3/15/23 36973 3-Th 3/16/23 30573 3-F 3/17/23 43573 3-Sa 3/18/23 24573 4-Su 3/19/23 24573 4-M 3/20/23 37073 4-T 3/21/23 24573 4-W 3/22/23 36973 4-Th 3/23/23 24573 4-F 3/24/23 24573 4-Sa 3/25/23 36973 5-Su 3/26/23 24573 5-M 3/27/23 36873 5-T 3/28/23 24573 5-W 3/29/23 37273 5-Th 3/30/23 36873 5-F 3/31/23 24573 Monthly Total 992463 Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1 Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 5

Monitoring Period:03/01/2023 - 03/31/2023 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 3/1/23 21.9 1-Th 3/2/23 21.3 1-F 3/3/23 21.2 1-Sa 3/4/23 21.6 2-Su 3/5/23 22.0 2-M 3/6/23 21.6 2-T 3/7/23 22.0 2-W 3/8/23 21.9 2-Th 3/9/23 22.0 2-F 3/10/23 22.4 2-Sa 3/11/23 22.6 3-Su 3/12/23 21.9 3-M 3/13/23 22.7 3-T 3/14/23 22.7 3-W 3/15/23 22.7 3-Th 3/16/23 22.4 3-F 3/17/23 22.4 3-Sa 3/18/23 22.6 4-Su 3/19/23 22.6 4-M 3/20/23 22.3 4-T 3/21/23 22.5 4-W 3/22/23 23.1 4-Th 3/23/23 23.4 4-F 3/24/23 22.5 4-Sa 3/25/23 22.2 5-Su 3/26/23 21.2 5-M 3/27/23 20.7 5-T 3/28/23 22.2 5-W 3/29/23 20.8 5-Th 3/30/23 19.5 5-F 3/31/23 19.5 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 4/13/2023 7:32:34 AM Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 5 of 5

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-062 DIC: 1316.20 DATE:

May 11, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station April 2023 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 2023. All monitoring parameters were within permit specifications for the month. Because of equipment issues, a temporary tanker truck continues to be used for sulfuric acid additions to the circulating water system to control the pH. This method results in greater variation of the blowdown pH than is typical.

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 Marshall Schmitt at (509) 372-5334.

Attachment:

NPDES Discharge Monitoring Report, April 2023 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 May 15, 2023 April 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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: 1874758 - 5/11/2023 10:37:37 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 O7dsLCqPA+XBp

+craaiJNQQZ9F11bY3NWPgM09WX1RKhNWUOWbDUoFvvIWd0zMRMh0zdkgSi2LFoE1b5tg/GU8URnxBMW2iQhgrPz UCkg+k=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Thursday May 11 2023 Report Received: 2023-05-11 10:37 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 5 Monitoring Period:04/01/2023 - 04/30/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Energy Northwest Columbia Generating Station Monitoring Point Week CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB2 1-Sa 4/1/23 C

C C

0 C

<0.1 C

2-Su 4/2/23 2.5 7.6 8.1 24.8 0.01 2-M 4/3/23 2.6 7.8 8.0 24.9 0.00 2-T 4/4/23 2.6 7.9 8.1 25.6 4.9*

13.5*

1.6*

18.4*

0.00 2-W 4/5/23 2.6 8.0 8.1 26.3 0.00 2-Th 4/6/23 1.9 7.7 8.5 0

26.5

<0.1 0.03 2-F 4/7/23 3.0 7.7 7.9 27.3 0.01 2-Sa 4/8/23 3.1 7.6 7.9 27.3 0.01 3-Su 4/9/23 3.0 7.6 7.9 27.7 0.01 3-M 4/10/23 3.0 7.6 7.9 27.2 0.01 3-T 4/11/23 3.1 7.7 7.8 24.8 0.00 3-W 4/12/23 3.0 7.6 7.9 24.1 0.00 3-Th 4/13/23 1.5 7.8 8.2 0

22.9

<0.1 0.04 3-F 4/14/23 3.1 7.7 8.3 23.0 0.03 3-Sa 4/15/23 3.1 7.7 7.8 24.0 0.02 4-Su 4/16/23 3.1 7.7 7.9 25.1 0.02 4-M 4/17/23 3.1 7.7 8.0 25.0 0.02 4-T 4/18/23 3.1 7.6 7.9 23.5 0.02 4-W 4/19/23 3.1 7.5 7.7 22.9 0.01 4-Th 4/20/23 3.1 7.6 8.1 23.0 0.01 4-F 4/21/23 3.1 8.1 8.3 25.3 0.01 4-Sa 4/22/23 3.1 8.0 8.4 25.4 0.01 5-Su 4/23/23 3.1 8.1 8.3 26.0 0.01 5-M 4/24/23 3.1 8.1 8.3 25.8 0.01 5-T 4/25/23 2.9 8.1 8.2 24.4 0.02 5-W 4/26/23 2.8 8.0 8.2 26.4 0.02 5-Th 4/27/23 2.7 7.8 8.2 26.5 0.02 5-F 4/28/23 2.7 7.9 8.0 26.0 0.01 5-Sa 4/29/23 2.7 7.9 8.1 26.5 0.02 6-Su 4/30/23 2.7 7.9 8.2 27.2 0.03 Instantaneous Minimum 7.5

>= 6.5 (RO)

Average Monthly 2.8 1.6 18.4

<= 5.6

<= 8.2

<= 53 Instantaneous Maximum 8.5

<= 9.0 (RO)

Monthly Total 0

<= 446 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 5 Monitoring Point Week CWB2 SSWD SSWD 1-Sa 4/1/23

<0.1 2-Su 4/2/23 2-M 4/3/23 2-T 4/4/23 2-W 4/5/23 2-Th 4/6/23

<0.1 2-F 4/7/23 2-Sa 4/8/23 3-Su 4/9/23 3-M 4/10/23 3-T 4/11/23 3-W 4/12/23 3-Th 4/13/23

<0.1 3-F 4/14/23 3-Sa 4/15/23 4-Su 4/16/23 4-M 4/17/23 4-T 4/18/23 4-W 4/19/23 4-Th 4/20/23 4-F 4/21/23 4-Sa 4/22/23 5-Su 4/23/23 5-M 4/24/23 5-T 4/25/23 5-W 4/26/23 5-Th 4/27/23 5-F 4/28/23 5-Sa 4/29/23 6-Su 4/30/23 Instantaneous Minimum Average Monthly Instantaneous Maximum Monthly Total

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 5 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment CWB Turbidity (Nephelometric)

Measured NTU 4/4/2023 4.9 Results from grab sample collected 4/4/2023 CWB Copper Total Micrograms/L (ug/L) 4/4/2023 13.5 Results from a 24-hr composite sample collected 4/3/2023-4/4/2023 CWB Chromium Total Micrograms/L (ug/L) 4/4/2023 1.6 Results from a 24-hr composite sample collected 4/3/2023-4/4/2023 CWB Zinc Total Micrograms/L (ug/L) 4/4/2023 18.4 Results from a 24-hr composite sample collected 4/3/2023-4/4/2023 CWB2 All Parameters Maximum daily total residual halogen from continuous TRH analyzer reported.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 5 Monitoring Period:04/01/2023 - 04/30/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 002 Energy Northwest Columbia Generating Station Monitoring Point Week Pnd 1-Sa 4/1/23 23509 2-Su 4/2/23 36009 2-M 4/3/23 36109 2-T 4/4/23 36109 2-W 4/5/23 35709 2-Th 4/6/23 23509 2-F 4/7/23 36009 2-Sa 4/8/23 35909 3-Su 4/9/23 35909 3-M 4/10/23 36209 3-T 4/11/23 23509 3-W 4/12/23 36109 3-Th 4/13/23 23509 3-F 4/14/23 35809 3-Sa 4/15/23 44409 4-Su 4/16/23 40009 4-M 4/17/23 35909 4-T 4/18/23 23509 4-W 4/19/23 35709 4-Th 4/20/23 23509 4-F 4/21/23 23509 4-Sa 4/22/23 36209 5-Su 4/23/23 35809 5-M 4/24/23 23509 5-T 4/25/23 37709 5-W 4/26/23 23509 5-Th 4/27/23 53209 5-F 4/28/23 23509 5-Sa 4/29/23 23509 6-Su 4/30/23 38409 Monthly Total 975870 Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 5 of 5 Monitoring Period:04/01/2023 - 04/30/2023 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 4/1/23 17.8 2-Su 4/2/23 20.0 2-M 4/3/23 20.3 2-T 4/4/23 22.3 2-W 4/5/23 22.6 2-Th 4/6/23 21.9 2-F 4/7/23 23.6 2-Sa 4/8/23 23.7 3-Su 4/9/23 23.5 3-M 4/10/23 23.4 3-T 4/11/23 22.3 3-W 4/12/23 22.7 3-Th 4/13/23 21.0 3-F 4/14/23 23.1 3-Sa 4/15/23 23.0 4-Su 4/16/23 23.4 4-M 4/17/23 22.5 4-T 4/18/23 13.8 4-W 4/19/23 13.1 4-Th 4/20/23 12.8 4-F 4/21/23 12.8 4-Sa 4/22/23 21.5 5-Su 4/23/23 23.2 5-M 4/24/23 22.9 5-T 4/25/23 22.5 5-W 4/26/23 23.0 5-Th 4/27/23 23.9 5-F 4/28/23 23.4 5-Sa 4/29/23 23.8 6-Su 4/30/23 23.6 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 5/11/2023 10:37:36 AM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-076 DIC: 1316.20 DATE:

June 14, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station May 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for May 2023. All monitoring parameters were within permit specifications for the month. Because of equipment issues, a temporary tanker truck continues to be used for sulfuric acid additions to the circulating water system to control the pH. This method results in greater variation of the blowdown pH than is typical. Due to refueling outage activities, temporary flow and pH measurements were used for part of 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 Marshall Schmitt at (509) 372-5334.

Attachment:

NPDES Discharge Monitoring Report, May 2023 KRB DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

M. Schmitt (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 14, 2023 May 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Marshall Schmitt, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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 5 Monitoring Period:05/01/2023 - 05/31/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Energy Northwest Columbia Generating Station Monitoring Point Week CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB2 1-M 5/1/23 2.8 7.9 8.3 27.0 0.02 1-T 5/2/23 2.8 7.9 8.2 27.3 8.4*

11.3*

1.36*

12.1*

0.02 1-W 5/3/23 2.7 7.6 8.1 30.0 0.03 1-Th 5/4/23 2.6 8.0 8.4 28.4 0.08 1-F 5/5/23 3.5 8.0 8.3 33.3 0.06 1-Sa 5/6/23 4.2 8.1 8.4 33.5 0.07 2-Su 5/7/23 3.1 7.9 8.2 17.4 0.07 2-M 5/8/23 3.4 8.1 8.2 18.0 0.04 2-T 5/9/23 2.1 7.9 8.1 17.2 0.03 2-W 5/10/23 2.1 7.6 8.1 24.5 0.02 2-Th 5/11/23 2.2 7.5 7.7 25.4 0.02 2-F 5/12/23 2.1 7.3 7.6 25.6 0.07 2-Sa 5/13/23 2.3 7.4 7.5 25.7 0.02 3-Su 5/14/23 2.3 7.4 7.7 24.2 0.02 3-M 5/15/23 2.3 7.5 7.6 24.0 0.03 3-T 5/16/23 2.3 7.5 7.6 24.8 0.05 3-W 5/17/23 2.3 7.5 7.6 22.9 0.02 3-Th 5/18/23 2.3 7.5 7.9 22.9 0.03 3-F 5/19/23 2.2 7.7 7.9 23.7 0.05 3-Sa 5/20/23 2.1 7.8 8.0 22.9 0.05 4-Su 5/21/23 2.3 7.8 7.9 22.9 0.05 4-M 5/22/23 2.3 7.8 7.9 23.2 0.05 4-T 5/23/23 2.2 7.7 7.9 22.9 0.04 4-W 5/24/23 2.3 7.7 7.9 23.0 0.01 4-Th 5/25/23 2.3 7.7 7.8 23.2 0.01 4-F 5/26/23 2.2 7.7 7.8 24.1 0.01 4-Sa 5/27/23 2.2 7.7 7.8 24.1 0.01 5-Su 5/28/23 2.2 7.7 7.8 24.5 0.01 5-M 5/29/23 2.2 7.8 7.9 25.0 0.01 5-T 5/30/23 2.2 7.8 7.9 25.0 0.01 5-W 5/31/23 2.2 7.7 7.9 M

30.0 M

0.01 Instantaneous Minimum 7.3

>= 6.5 (RO)

Average Monthly 2.5 1.36 12.1

<= 5.6

<= 8.2

<= 53 Instantaneous Maximum 8.4

<= 9.0 (RO)

Monthly Total M

<= 446 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 5 Monitoring Point Week CWB2 SSWD SSWD 1-M 5/1/23 1-T 5/2/23 1-W 5/3/23 1-Th 5/4/23 1-F 5/5/23 1-Sa 5/6/23 2-Su 5/7/23 2-M 5/8/23 2-T 5/9/23 2-W 5/10/23 2-Th 5/11/23 2-F 5/12/23 2-Sa 5/13/23 3-Su 5/14/23 3-M 5/15/23 3-T 5/16/23 3-W 5/17/23 3-Th 5/18/23 3-F 5/19/23 3-Sa 5/20/23 4-Su 5/21/23 4-M 5/22/23 4-T 5/23/23 4-W 5/24/23 4-Th 5/25/23 4-F 5/26/23 4-Sa 5/27/23 5-Su 5/28/23 5-M 5/29/23 5-T 5/30/23 5-W 5/31/23 M

Instantaneous Minimum Average Monthly Instantaneous Maximum Monthly Total

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 5 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment CWB Turbidity (Nephelometric)

Measured NTU 5/2/2023 8.4 Results from grab sample collected 5/2/23 CWB Copper Total Micrograms/L (ug/L) 5/2/2023 11.3 Results from 24-hr composite sample collected 5/1/2023-5/2/2023 CWB Chromium Total Micrograms/L (ug/L) 5/2/2023 1.36 Results from 24-hr composite sample collected 5/1/2023-5/2/2023 CWB Zinc Total Micrograms/L (ug/L) 5/2/2023 12.1 Results from 24-hr composite sample collected 5/1/2023-5/2/2023 CWB2 All Parameters Maximum daily total residual halogen from continuous TRH analyzer reported.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 5 Monitoring Period:05/01/2023 - 05/31/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 002 Energy Northwest Columbia Generating Station Monitoring Point Week Pnd 1-M 5/1/23 25646 1-T 5/2/23 10746 1-W 5/3/23 25646 1-Th 5/4/23 25646 1-F 5/5/23 25746 1-Sa 5/6/23 25546 2-Su 5/7/23 10746 2-M 5/8/23 25746 2-T 5/9/23 10746 2-W 5/10/23 25846 2-Th 5/11/23 10746 2-F 5/12/23 25746 2-Sa 5/13/23 10746 3-Su 5/14/23 25646 3-M 5/15/23 10746 3-T 5/16/23 25946 3-W 5/17/23 10746 3-Th 5/18/23 25946 3-F 5/19/23 25346 3-Sa 5/20/23 25646 4-Su 5/21/23 25746 4-M 5/22/23 26046 4-T 5/23/23 25946 4-W 5/24/23 25946 4-Th 5/25/23 21746 4-F 5/26/23 29646 4-Sa 5/27/23 10746 5-Su 5/28/23 10746 5-M 5/29/23 25646 5-T 5/30/23 25546 5-W 5/31/23 10746 Monthly Total 647826 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: 5 of 5 Monitoring Period:05/01/2023 - 05/31/2023 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 5/1/23 22.8 1-T 5/2/23 22.0 1-W 5/3/23 20.4 1-Th 5/4/23 22.5 1-F 5/5/23 13.3 1-Sa 5/6/23 5.7 2-Su 5/7/23 5.8 2-M 5/8/23 5.8 2-T 5/9/23 5.8 2-W 5/10/23 5.8 2-Th 5/11/23 5.8 2-F 5/12/23 5.8 2-Sa 5/13/23 5.8 3-Su 5/14/23 5.8 3-M 5/15/23 5.8 3-T 5/16/23 5.8 3-W 5/17/23 5.8 3-Th 5/18/23 5.8 3-F 5/19/23 5.8 3-Sa 5/20/23 5.8 4-Su 5/21/23 5.8 4-M 5/22/23 5.8 4-T 5/23/23 5.8 4-W 5/24/23 5.8 4-Th 5/25/23 5.8 4-F 5/26/23 5.8 4-Sa 5/27/23 5.8 5-Su 5/28/23 5.8 5-M 5/29/23 5.8 5-T 5/30/23 5.8 5-W 5/31/23 5.8 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 6/14/2023 8:47:05 AM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-082 DIC: 1316.20 DATE:

July 13, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station June 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for June 2023. All monitoring parameters were within permit specifications for the month. Because of equipment issues, a temporary tanker truck continues to be used for sulfuric acid additions to the circulating water system to control the pH. This method results in greater variation of the blowdown pH than is typical. Due to refueling outage activities, temporary flow and pH measurements were used for part of 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 2023 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 January 30, 2024 CGS June 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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 5 Monitoring Period:06/01/2023 - 06/30/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 001 Columbia River Energy Northwest Columbia Generating Station Monitoring Point Week CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB CWB2 1-Th 6/1/23 2.2 7.8 8.0 24.8 0.01 1-F 6/2/23 2.3 7.8 7.9 25.5 0.01 1-Sa 6/3/23 0.3 7.7 7.9 0

29.9 0.00 2-Su 6/4/23 2.1 7.7 8.3 24.8 0.08 2-M 6/5/23 2.2 8.2 8.2 21.1 0.08 2-T 6/6/23 2.4 7.5 8.3 19.5 0.05 2-W 6/7/23 2.4 7.6 7.7 19.8 10*

14.3*

0.84*

35*

0.03 2-Th 6/8/23 2.6 7.5 7.6 20.7 0.03 2-F 6/9/23 2.6 7.5 7.6 22.6 0.02 2-Sa 6/10/23 2.6 7.5 7.6 21.6 0.01 3-Su 6/11/23 2.6 7.4 7.5 21.1 0.01 3-M 6/12/23 2.6 7.4 7.5 22.6 0.01 3-T 6/13/23 1.4 7.4 7.5 22.9 0.01 3-W 6/14/23 C

C C

0 C

C 3-Th 6/15/23 C

C C

0 C

C 3-F 6/16/23 C

C C

0 C

C 3-Sa 6/17/23 C

C C

0 C

C 4-Su 6/18/23 C

C C

0 C

C 4-M 6/19/23 C

C C

0 C

<0.1 C

4-T 6/20/23 0.7 7.2 8.1 26.3 0.03 4-W 6/21/23 0.6 7.7 8.0 0

27.3

<0.1 0.09 4-Th 6/22/23 1.6 7.8 8.3 28.1 0.04 4-F 6/23/23 3.0 7.8 7.8 30.3 0.04 4-Sa 6/24/23 1.9 7.6 7.8 0

30.4 0.03 5-Su 6/25/23 0.7 8.0 8.4 0

29.4

<0.1 0.07 5-M 6/26/23 5.0 7.6 8.3 31.8 0.06 5-T 6/27/23 3.8 7.6 7.8 31.7 0.04 5-W 6/28/23 2.7 7.5 7.7 32.4 0.04 5-Th 6/29/23 1.6 7.5 7.8 0

32.3

<0.1 0.04 5-F 6/30/23 2.7 7.5 7.6 32.8 0.03 Instantaneous Minimum 7.2

>= 6.5 (RO)

Average Monthly 1.8 0.84 35

<= 5.6

<= 8.2

<= 53 Instantaneous Maximum 8.4

<= 9.0 (RO)

Monthly Total 0

<= 446 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 5 Monitoring Point Week CWB2 SSWD SSWD 1-Th 6/1/23 1-F 6/2/23 1-Sa 6/3/23 2-Su 6/4/23 2-M 6/5/23 2-T 6/6/23 2-W 6/7/23 2-Th 6/8/23 2-F 6/9/23 2-Sa 6/10/23 3-Su 6/11/23 3-M 6/12/23 3-T 6/13/23 3-W 6/14/23 3-Th 6/15/23 3-F 6/16/23 3-Sa 6/17/23 4-Su 6/18/23 4-M 6/19/23

<0.1 4-T 6/20/23 4-W 6/21/23

<0.1 4-Th 6/22/23 4-F 6/23/23 4-Sa 6/24/23 5-Su 6/25/23

<0.1 5-M 6/26/23 5-T 6/27/23 5-W 6/28/23 5-Th 6/29/23

<0.1 5-F 6/30/23 Instantaneous Minimum Average Monthly Instantaneous Maximum Monthly Total

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 5 Outfall: 001 -

Monitoring Point Parameter Sample Date/

Statistical Base Value Notes/Comment CWB Turbidity (Nephelometric)

Measured NTU 6/7/2023 10 Results from grab sample collected 6/7/23 CWB Copper Total Micrograms/L (ug/L) 6/7/2023 14.3 Results from 24-hr composite sample collected 6/6/2023-6/7/2023 CWB Chromium Total Micrograms/L (ug/L) 6/7/2023 0.84 Results from 24-hr composite sample collected 6/6/2023-6/7/2023 CWB Zinc Total Micrograms/L (ug/L) 6/7/2023 35 Results from 24-hr composite sample collected 6/6/2023-6/7/2023 CWB2 All Parameters Maximum daily total residual halogen from continuous TRH analyzer reported.

SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 5 Monitoring Period:06/01/2023 - 06/30/2023 Facility County: Benton WA0025151 Permit Number:

Permittee:

Receiving Waterbody:

Outfall: 002 Energy Northwest Columbia Generating Station Monitoring Point Week Pnd 1-Th 6/1/23 9381 1-F 6/2/23 24381 1-Sa 6/3/23 24281 2-Su 6/4/23 9381 2-M 6/5/23 24281 2-T 6/6/23 24181 2-W 6/7/23 24081 2-Th 6/8/23 9381 2-F 6/9/23 9381 2-Sa 6/10/23 39281 3-Su 6/11/23 9381 3-M 6/12/23 9381 3-T 6/13/23 9381 3-W 6/14/23 9381 3-Th 6/15/23 9381 3-F 6/16/23 9381 3-Sa 6/17/23 9381 4-Su 6/18/23 9381 4-M 6/19/23 9381 4-T 6/20/23 9381 4-W 6/21/23 9381 4-Th 6/22/23 9381 4-F 6/23/23 9381 4-Sa 6/24/23 9381 5-Su 6/25/23 9381 5-M 6/26/23 9381 5-T 6/27/23 9381 5-W 6/28/23 9381 5-Th 6/29/23 9381 5-F 6/30/23 9381 Monthly Total 385630 Reporting Codes Used: B - Below Detection Limit/No Detection, C - No Discharge Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 5 of 5 Monitoring Period:06/01/2023 - 06/30/2023 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 6/1/23 5.8 1-F 6/2/23 5.8 1-Sa 6/3/23 5.8 2-Su 6/4/23 5.8 2-M 6/5/23 5.8 2-T 6/6/23 5.8 2-W 6/7/23 5.8 2-Th 6/8/23 5.8 2-F 6/9/23 5.8 2-Sa 6/10/23 5.8 3-Su 6/11/23 5.8 3-M 6/12/23 5.8 3-T 6/13/23 5.8 3-W 6/14/23 5.8 3-Th 6/15/23 5.8 3-F 6/16/23 5.8 3-Sa 6/17/23 5.8 4-Su 6/18/23 4.7 4-M 6/19/23 4.5 4-T 6/20/23 8.4 4-W 6/21/23 16.3 4-Th 6/22/23 18.9 4-F 6/23/23 25.6 4-Sa 6/24/23 25.2 5-Su 6/25/23 24.3 5-M 6/26/23 29.7 5-T 6/27/23 27.9 5-W 6/28/23 26.8 5-Th 6/29/23 26.6 5-F 6/30/23 27.6 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.

Signature Date

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-096 DIC: 1316.20 DATE:

August 15, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station July 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for July 2023. 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 2023 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)

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

Columbia Generating Station Page 2 of 2 August 16, 2023 CGS July 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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: 1890093 - 8/15/2023 2:54:02 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 2TIPOB2a0mYy3Kz0hVvC0O/nvzY1uFWc6m6ovmB9Uzq3DLBUJDq3uakNWDhep6TWmTRwmXywjbeFw5wWkVKrggD wO0QbOkcQbE8T8gStj0Y=

Document Name Or Description Document Name Submitted Copy of Record for Energy Northwest Copy of Record EnergyNorthwest Tuesday August 15 2023 Report Received: 2023-08-15 14:54 Page 1 of 1 Pages

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:07/01/2023 - 07/31/2023 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 7/1/23 5.0 7.5 7.6 0.02 33.1 2-Su 7/2/23 5.0 7.6 7.7 0.01 31.6 2-M 7/3/23 4.9 7.7 8.0 0.03 30.3

<1.0*

12.1*

2-T 7/4/23 4.9 7.6 7.8 0.02 31.8 2-W 7/5/23 4.9 7.6 7.9 0.07 31.9 2-Th 7/6/23 5.0 7.5 8.0 0.01 32.5 2-F 7/7/23 5.0 7.3 8.0 0.03 32.5 2-Sa 7/8/23 5.0 7.7 7.8 0.02 33.2 3-Su 7/9/23 5.0 7.6 7.7 0.01 33.1 3-M 7/10/23 5.1 7.6 7.9 0.03 33.1 3-T 7/11/23 5.1 7.7 8.0 0.03 32.5 3-W 7/12/23 5.0 7.7 7.9 0.03 32.2 3-Th 7/13/23 5.0 7.8 8.3 0.03 32.5 3-F 7/14/23 4.9 8.0 8.3 0.03 32.5 3-Sa 7/15/23 4.9 7.9 8.0 0.03 33.4 4-Su 7/16/23 4.9 7.9 7.9 0.05 33.0 4-M 7/17/23 5.0 7.8 8.1 0.03 32.6 4-T 7/18/23 5.2 8.0 8.0 0.03 31.8 4-W 7/19/23 5.2 8.0 8.0 0.03 32.0 4-Th 7/20/23 5.2 7.9 8.1 0.03 32.9 4-F 7/21/23 5.2 7.9 8.0 0.03 33.0 4-Sa 7/22/23 5.1 7.9 8.0 0.03 33.0 5-Su 7/23/23 5.2 7.8 8.0 0.02 33.1 5-M 7/24/23 5.2 7.7 7.9 0.03 33.6 5-T 7/25/23 5.2 7.7 7.9 0.02 31.7 5-W 7/26/23 5.2 7.8 7.9 0.01 31.0 5-Th 7/27/23 5.2 7.6 7.9 0.03 31.7 5-F 7/28/23 5.1 7.9 8.0 0.03 31.9 5-Sa 7/29/23 5.1 7.9 8.0 0.05 32.5 6-Su 7/30/23 5.2 7.9 8.0 0.03 31.2 6-M 7/31/23 5.2 7.9 8.0 M

0.02 31.6 5.87E+08*

Daily Minimum 7.3 27.4

>= 6.5 (RO)

Report Only Average Monthly 5.1 5.87e+008

<1.0 12.1 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 5.2 8.3 0.07 33.6

<1.0 12.1

<= 9.4

<= 9.0 (RO)

<= 0.1 Report Only

<= 16.4

<= 107 Monthly Total M

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: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 2 of 4 Monitoring Point Week SSWD 1-Sa 7/1/23 2-Su 7/2/23 2-M 7/3/23 2-T 7/4/23 2-W 7/5/23 2-Th 7/6/23 2-F 7/7/23 2-Sa 7/8/23 3-Su 7/9/23 3-M 7/10/23 3-T 7/11/23 3-W 7/12/23 3-Th 7/13/23 3-F 7/14/23 3-Sa 7/15/23 4-Su 7/16/23 4-M 7/17/23 4-T 7/18/23 4-W 7/19/23 4-Th 7/20/23 4-F 7/21/23 4-Sa 7/22/23 5-Su 7/23/23 5-M 7/24/23 5-T 7/25/23 5-W 7/26/23 5-Th 7/27/23 5-F 7/28/23 5-Sa 7/29/23 6-Su 7/30/23 6-M 7/31/23 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 Heat Load Million Kilocalories 7/31/2023 5.87E+08 Average monthly heat load calculated using the following formula: [average monthly temperature (°C)] x [average monthly flow (MGD)] x [3.78x106].

CWB Chromium Total Micrograms/L (ug/L) 7/3/2023 Bl<1.0 Results from 24-hr composite sample collected 07/02/23-07/03/23 CWB Zinc Total Micrograms/L (ug/L) 7/3/2023 12.1 Results from 24-hr composite sample collected 07/02/23-07/03/23 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:07/01/2023 - 07/31/2023 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 7/1/23 30.2 2-Su 7/2/23 27.9 2-M 7/3/23 27.4 2-T 7/4/23 28.1 2-W 7/5/23 29.8 2-Th 7/6/23 30.3 2-F 7/7/23 30.2 2-Sa 7/8/23 30.1 3-Su 7/9/23 30.4 3-M 7/10/23 27.9 3-T 7/11/23 27.3 3-W 7/12/23 29.5 3-Th 7/13/23 29.8 3-F 7/14/23 29.8 3-Sa 7/15/23 30.4 4-Su 7/16/23 30.6 4-M 7/17/23 29.5 4-T 7/18/23 29.0 4-W 7/19/23 29.6 4-Th 7/20/23 30.6 4-F 7/21/23 30.7 4-Sa 7/22/23 30.5 5-Su 7/23/23 29.8 5-M 7/24/23 30.0 5-T 7/25/23 29.6 5-W 7/26/23 28.7 5-Th 7/27/23 29.9 5-F 7/28/23 29.4 5-Sa 7/29/23 29.7 6-Su 7/30/23 29.9 6-M 7/31/23 29.1 Average Monthly 29.5 Report Only Monthly Total 915.9 Report Only Reporting Codes Used: B - Below Detection Limit/No Detection, 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 8/15/2023 2:54:01 PM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-101 DIC: 1316.20 DATE:

September 14, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station August 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for August 2023. 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 2023 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)

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

Columbia Generating Station Page 2 of 2 January 30, 2024 CGS August 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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:08/01/2023 - 08/31/2023 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 8/1/23 5.2 7.9 8.0 0.03 31.6 1-W 8/2/23 5.2 7.9 8.0 0.03 32.2 1.3*

17.7*

1-Th 8/3/23 5.2 7.9 8.0 0.03 31.9 1-F 8/4/23 5.2 7.9 8.0 0.02 32.3 1-Sa 8/5/23 5.1 7.8 7.9 0.03 32.2 2-Su 8/6/23 5.1 7.8 7.9 0.03 32.9 2-M 8/7/23 5.1 7.7 7.9 0.02 32.5 2-T 8/8/23 5.1 7.6 8.0 0.03 32.1 2-W 8/9/23 5.1 8.0 8.3 0.02 32.2 2-Th 8/10/23 5.1 8.2 8.4 0.02 31.3 2-F 8/11/23 5.2 8.3 8.5 0.01 30.2 2-Sa 8/12/23 5.2 7.8 8.5 0.02 30.2 3-Su 8/13/23 5.2 7.7 7.9 0.02 30.4 3-M 8/14/23 5.2 7.7 7.8 0.02 31.4 3-T 8/15/23 5.2 7.7 7.9 0.02 32.2 3-W 8/16/23 5.2 7.8 7.9 0.07 32.0 3-Th 8/17/23 5.2 7.8 7.9 0.03 32.1 3-F 8/18/23 5.2 7.8 7.9 0.02 31.1 3-Sa 8/19/23 5.2 7.8 8.0 0.01 32.4 4-Su 8/20/23 5.2 7.9 8.0 0.02 31.6 4-M 8/21/23 5.1 7.9 8.1 0.07 29.9 4-T 8/22/23 5.1 8.0 8.1 0.02 30.0 4-W 8/23/23 5.2 8.0 8.1 0.02 29.1 4-Th 8/24/23 5.1 8.0 8.1 0.05 28.8 4-F 8/25/23 5.1 7.9 8.0 0.05 29.1 4-Sa 8/26/23 5.1 7.9 8.0 0.04 30.6 5-Su 8/27/23 5.1 7.9 8.0 0.05 30.1 5-M 8/28/23 5.2 7.9 8.3 0.06 30.3 5-T 8/29/23 5.2 8.0 8.1 0.02 30.3 5-W 8/30/23 5.2 7.9 8.1 0.02 28.7 5-Th 8/31/23 5.2 8.0 8.2 M

0.01 27.9 5.71E+08*

Daily Minimum 7.6 25.5

>= 6.5 (RO)

Report Only Average Monthly 5.1 5.71e+008 1.3 17.7 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 5.2 8.5 0.07 32.9 1.3 17.7

<= 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 8/1/23 1-W 8/2/23 1-Th 8/3/23 1-F 8/4/23 1-Sa 8/5/23 2-Su 8/6/23 2-M 8/7/23 2-T 8/8/23 2-W 8/9/23 2-Th 8/10/23 2-F 8/11/23 2-Sa 8/12/23 3-Su 8/13/23 3-M 8/14/23 3-T 8/15/23 3-W 8/16/23 3-Th 8/17/23 3-F 8/18/23 3-Sa 8/19/23 4-Su 8/20/23 4-M 8/21/23 4-T 8/22/23 4-W 8/23/23 4-Th 8/24/23 4-F 8/25/23 4-Sa 8/26/23 5-Su 8/27/23 5-M 8/28/23 5-T 8/29/23 5-W 8/30/23 5-Th 8/31/23 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 Heat Load Million Kilocalories 8/31/2023 5.71E+08 Average monthly heat load calculated using the following formula: [average monthly temperature (°C)] x [average monthly flow (MGD)] x [3.78x10^6].

CWB Chromium Total Micrograms/L (ug/L) 8/2/2023 1.3 Results from 24-hr composite sample collected 08/01/23-08/02/23 CWB Zinc Total Micrograms/L (ug/L) 8/2/2023 17.7 Results from 24-hr composite sample collected 08/01/23-08/02/23 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:08/01/2023 - 08/31/2023 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 8/1/23 30.0 1-W 8/2/23 29.8 1-Th 8/3/23 28.3 1-F 8/4/23 29.6 1-Sa 8/5/23 29.1 2-Su 8/6/23 28.8 2-M 8/7/23 28.5 2-T 8/8/23 29.3 2-W 8/9/23 29.7 2-Th 8/10/23 29.6 2-F 8/11/23 29.4 2-Sa 8/12/23 30.6 3-Su 8/13/23 31.2 3-M 8/14/23 31.3 3-T 8/15/23 30.9 3-W 8/16/23 31.0 3-Th 8/17/23 30.5 3-F 8/18/23 31.0 3-Sa 8/19/23 29.1 4-Su 8/20/23 29.4 4-M 8/21/23 29.2 4-T 8/22/23 28.4 4-W 8/23/23 28.8 4-Th 8/24/23 29.2 4-F 8/25/23 29.7 4-Sa 8/26/23 29.6 5-Su 8/27/23 30.4 5-M 8/28/23 30.7 5-T 8/29/23 28.3 5-W 8/30/23 29.3 5-Th 8/31/23 28.0 Average Monthly 29.6 Report Only Monthly Total 918.5 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.

Signature Date

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-116 DIC: 1316.20 DATE:

October 10, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station September 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for September 2023. 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 2023 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)

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

Columbia Generating Station Page 2 of 2 January 30, 2024 CGS September 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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:09/01/2023 - 09/30/2023 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-F 9/1/23 5.2 8.0 8.2 0.00 28.9 1-Sa 9/2/23 5.2 8.0 8.1 0.00 29.3 2-Su 9/3/23 5.1 7.9 8.0 0.00 30.2 2-M 9/4/23 5.1 8.0 8.1 0.00 29.2 2-T 9/5/23 1.3 8.0 8.5 0

0.08 29.1 2-W 9/6/23 2.8 8.0 8.5 0.07 27.9 2-Th 9/7/23 2.8 8.0 8.1 0.01 28.2 1.9*

22.5*

2-F 9/8/23 2.7 8.1 8.2 0.00 28.2 2-Sa 9/9/23 2.7 8.0 8.2 0.00 28.9 3-Su 9/10/23 2.7 7.9 8.1 0.00 28.8 3-M 9/11/23 2.8 8.0 8.2 0.03 29.2 3-T 9/12/23 2.8 8.1 8.2 0.02 29.1 3-W 9/13/23 2.8 8.1 8.2 0.03 28.9 3-Th 9/14/23 2.8 8.1 8.2 0.02 28.7 3-F 9/15/23 2.8 8.0 8.2 0.04 28.8 3-Sa 9/16/23 2.8 8.1 8.2 0.03 27.9 4-Su 9/17/23 1.4 8.1 8.2 0

0.05 28.0 4-M 9/18/23 0.2 7.8 8.5 0

0.06 26.3 4-T 9/19/23 2.2 7.8 8.6 0

0.06 27.9 4-W 9/20/23 C

C C

0 C

C 4-Th 9/21/23 1.8 7.7 8.5 0

0.08 26.6 4-F 9/22/23 3.5 7.7 7.8 0.04 27.3 4-Sa 9/23/23 3.5 7.6 7.7 0.04 27.3 5-Su 9/24/23 3.5 7.5 7.6 0.03 27.3 5-M 9/25/23 3.5 7.4 8.1 0.08 28.0 5-T 9/26/23 3.4 7.9 8.0 0.03 28.1 5-W 9/27/23 3.4 7.7 7.9 0.02 28.2 5-Th 9/28/23 1.9 7.8 8.4 0

0.08 26.7 5-F 9/29/23 2.8 7.9 8.0 0.03 26.3 5-Sa 9/30/23 2.8 7.8 7.9 0.07 25.9 2.90E+08*

Daily Minimum 7.4 23.4

>= 6.5 (RO)

Report Only Average Monthly 2.9 2.9e+008 1.9 22.5 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 5.2 8.6 0.08 30.2 1.9 22.5

<= 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-F 9/1/23 1-Sa 9/2/23 2-Su 9/3/23 2-M 9/4/23 2-T 9/5/23 2-W 9/6/23 2-Th 9/7/23 2-F 9/8/23 2-Sa 9/9/23 3-Su 9/10/23 3-M 9/11/23 3-T 9/12/23 3-W 9/13/23 3-Th 9/14/23 3-F 9/15/23 3-Sa 9/16/23 4-Su 9/17/23 4-M 9/18/23 4-T 9/19/23 4-W 9/20/23 4-Th 9/21/23 4-F 9/22/23 4-Sa 9/23/23 5-Su 9/24/23 5-M 9/25/23 5-T 9/26/23 5-W 9/27/23 5-Th 9/28/23 5-F 9/29/23 5-Sa 9/30/23 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 Heat Load Million Kilocalories 9/30/2023 2.90E+08 Average monthly heat load calculated using the following formula: [average monthly temperature (°C)] x [average monthly flow (MGD)] x [3.78x10^6].

CWB Chromium Total Micrograms/L (ug/L) 9/7/2023 1.9 Results from 24-hr composite sample collected 09/06/23-09/07/23 CWB Zinc Total Micrograms/L (ug/L) 9/7/2023 22.5 Results from 24-hr composite sample collected 09/06/23-09/07/23 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:09/01/2023 - 09/30/2023 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 9/1/23 28.4 1-Sa 9/2/23 28.9 2-Su 9/3/23 29.3 2-M 9/4/23 28.8 2-T 9/5/23 24.7 2-W 9/6/23 26.6 2-Th 9/7/23 26.7 2-F 9/8/23 26.7 2-Sa 9/9/23 26.7 3-Su 9/10/23 27.0 3-M 9/11/23 26.5 3-T 9/12/23 26.3 3-W 9/13/23 26.2 3-Th 9/14/23 26.3 3-F 9/15/23 25.9 3-Sa 9/16/23 26.5 4-Su 9/17/23 25.3 4-M 9/18/23 23.5 4-T 9/19/23 23.9 4-W 9/20/23 19.8 4-Th 9/21/23 21.1 4-F 9/22/23 23.3 4-Sa 9/23/23 23.1 5-Su 9/24/23 23.4 5-M 9/25/23 23.2 5-T 9/26/23 23.6 5-W 9/27/23 23.0 5-Th 9/28/23 21.5 5-F 9/29/23 22.3 5-Sa 9/30/23 22.9 Average Monthly 25.0467 Report Only Monthly Total 751.6 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.

Signature Date

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-124 DIC: 1316.20 DATE:

November 13, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station October 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for October 2023.

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 2023 KRB

Columbia Generating Station Page 2 of 2 January 30, 2024 CGS October 2023 DMR 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, Manager, Environmental Services Approved by: Denis Mehinagic, Environmental Scientist, E&RP

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 1 of 4 Monitoring Period:10/01/2023 - 10/31/2023 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 10/1/23 2.7 7.7 7.8 0.04 26.3 1-M 10/2/23 C

C C

0 C

<0.1*

26.3 1-T 10/3/23 2.5 7.9 8.4 0.03 27.6 1-W 10/4/23 2.8 7.8 8.0 0.03 27.7 1.3*

14.2*

1-Th 10/5/23 2.8 7.8 7.9 0.05 27.7 1-F 10/6/23 2.8 7.6 7.8 0.03 27.6 1-Sa 10/7/23 2.8 7.6 7.7 0.05 27.6 2-Su 10/8/23 2.8 7.4 7.6 0.05 28.0 2-M 10/9/23 2.8 7.6 8.1 0.04 27.9 2-T 10/10/23 2.8 8.0 8.1 0.03 26.9 2-W 10/11/23 2.8 7.9 8.0 0.03 26.9 2-Th 10/12/23 2.7 7.9 8.2 0.03 26.4 2-F 10/13/23 2.7 8.0 8.1 0.03 26.2 2-Sa 10/14/23 2.7 7.9 8.0 0.03 26.5 3-Su 10/15/23 2.7 7.8 7.9 0.03 26.9 3-M 10/16/23 2.7 7.9 8.2 0.02 27.3 3-T 10/17/23 2.8 8.0 8.1 0.02 27.0 3-W 10/18/23 0.3 8.0 8.0 0

0.02

<0.1*

26.0 3-Th 10/19/23 1.2 7.8 8.5 0.07 27.4 3-F 10/20/23 2.8 7.9 8.1 0.01 27.9 3-Sa 10/21/23 2.9 7.9 8.0 0.02 27.8 4-Su 10/22/23 2.9 7.9 8.0 0.06 26.7 4-M 10/23/23 2.9 7.9 8.2 0.03 26.6 4-T 10/24/23 2.9 8.0 8.1 0.01 25.5 4-W 10/25/23 2.9 8.0 8.1 0.01 22.1 4-Th 10/26/23 2.9 8.0 8.2 0.02 21.7 4-F 10/27/23 2.9 8.0 8.0 0.03 23.5 4-Sa 10/28/23 2.9 7.9 8.0 0.02 23.7 5-Su 10/29/23 2.9 7.9 8.0 0.02 22.6 5-M 10/30/23 2.9 7.9 8.1 0.01 25.0 5-T 10/31/23 2.9 7.9 8.0 0.01 24.8 2.39E+08 Daily Minimum 7.4 18.0

>= 6.5 (RO)

Report Only Average Monthly 2.6 2.39e+008 1.3 14.2 Report Only

<= 5.6

<= 1.27e

+009

<= 8.2

<= 53 Daily Maximum 2.9 8.5 0.07 28.0 1.3 14.2

<= 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 10/1/23 1-M 10/2/23 1-T 10/3/23 1-W 10/4/23 1-Th 10/5/23 1-F 10/6/23 1-Sa 10/7/23 2-Su 10/8/23 2-M 10/9/23 2-T 10/10/23 2-W 10/11/23 2-Th 10/12/23 2-F 10/13/23 2-Sa 10/14/23 3-Su 10/15/23 3-M 10/16/23 3-T 10/17/23 3-W 10/18/23 3-Th 10/19/23 3-F 10/20/23 3-Sa 10/21/23 4-Su 10/22/23 4-M 10/23/23 4-T 10/24/23 4-W 10/25/23 4-Th 10/26/23 4-F 10/27/23 4-Sa 10/28/23 5-Su 10/29/23 5-M 10/30/23 5-T 10/31/23 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) 10/2/2023 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) 10/18/2023 Bl<0.1 Grab sample verification of TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 10/4/2023 1.3 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 10/3/23-10/4/23 CWB Zinc Total Micrograms/L (ug/L) 10/4/2023 14.2 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 10/3/23-10/4/23 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Monitoring Period:10/01/2023 - 10/31/2023 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 10/1/23 22.6 1-M 10/2/23 19.9 1-T 10/3/23 22.5 1-W 10/4/23 22.9 1-Th 10/5/23 22.8 1-F 10/6/23 22.6 1-Sa 10/7/23 22.6 2-Su 10/8/23 22.9 2-M 10/9/23 20.0 2-T 10/10/23 21.9 2-W 10/11/23 21.9 2-Th 10/12/23 22.1 2-F 10/13/23 21.7 2-Sa 10/14/23 22.3 3-Su 10/15/23 22.6 3-M 10/16/23 22.4 3-T 10/17/23 22.5 3-W 10/18/23 20.2 3-Th 10/19/23 20.7 3-F 10/20/23 22.7 3-Sa 10/21/23 23.1 4-Su 10/22/23 22.9 4-M 10/23/23 22.8 4-T 10/24/23 17.7 4-W 10/25/23 14.9 4-Th 10/26/23 18.0 4-F 10/27/23 20.8 4-Sa 10/28/23 20.1 5-Su 10/29/23 20.1 5-M 10/30/23 20.3 5-T 10/31/23 20.6 Average Monthly 21.3 Report Only Monthly Total 660.9 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.

Signature Date

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-133 DIC: 1316.20 DATE:

December 12, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Ashley Mowery, Environmental Technician

SUBJECT:

Columbia Generating Station November 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for November 2023.

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, November 2023 AJM

Columbia Generating Station Page 2 of 2 January 30, 2024 CGS November 2023 DMR 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: Ashley Mowery, Environmental Technician, Environmental Services Reviewed by: Kris Byers, Environmental Scientist, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, 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:11/01/2023 - 11/30/2023 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 11/1/23 2.9 7.7 8.0 0.01 24.9 1-Th 11/2/23 2.9 7.7 7.8 0.01 25.7 1-F 11/3/23 2.9 7.7 7.8 0.01 26.3 1-Sa 11/4/23 2.9 7.7 7.8 0.01 26.9 2-Su 11/5/23 2.9 7.7 7.8 0.02 27.1 2-M 11/6/23 2.9 7.7 7.9 0.03 27.0 2-T 11/7/23 2.9 7.7 7.8 0.02 27.3 1.41*

10.4*

2-W 11/8/23 2.9 7.7 7.8 0.01 25.6 2-Th 11/9/23 2.9 7.8 7.9 0.03 24.8 2-F 11/10/23 2.9 7.8 7.9 0.01 25.6 2-Sa 11/11/23 2.9 7.7 7.8 0.02 28.1 3-Su 11/12/23 2.9 7.7 7.8 0.02 26.4 3-M 11/13/23 2.9 7.7 7.8 0.03 25.9 3-T 11/14/23 2.9 7.7 7.8 0.03 25.1 3-W 11/15/23 2.9 7.7 7.8 0.02 24.2 3-Th 11/16/23 2.9 7.7 7.8 0.03 24.3 3-F 11/17/23 2.9 7.7 7.8 0.01 23.4 3-Sa 11/18/23 2.9 7.7 7.8 0.01 23.7 4-Su 11/19/23 2.9 7.7 7.8 0.01 26.4 4-M 11/20/23 2.9 7.7 7.9 0.02 25.1 4-T 11/21/23 3.0 7.7 7.8 0.01 23.9 4-W 11/22/23 2.9 7.7 7.8 0.01 24.5 4-Th 11/23/23 2.9 7.7 7.8 0.01 24.6 4-F 11/24/23 2.9 7.7 7.8 0.01 23.9 4-Sa 11/25/23 2.9 7.7 7.8 0.01 23.7 5-Su 11/26/23 2.9 7.7 7.7 0.02 21.8 5-M 11/27/23 2.1 7.7 7.9 0.06 21.7 5-T 11/28/23 C

C C

0 C

C 5-W 11/29/23 0.4 7.6 8.2 0.04

<0.1*

19.9 5-Th 11/30/23 3.0 7.7 8.2 0.05 24.0 Daily Minimum 7.6 17.0

>= 6.5 (RO)

Report Only Average Monthly 2.7 1.41 10.4 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3

8.2 0.06 28.1 1.41 10.4

<= 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) 11/29/2023 Bl<0.1 Grab sample verification of TRH <0.1 prior to resuming blowdown.

CWB Chromium Total Micrograms/L (ug/L) 11/7/2023 1.41 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 11/6/23-11/7/23 CWB Zinc Total Micrograms/L (ug/L) 11/7/2023 10.4 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 11/6/23-11/7/23 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 3 Monitoring Period:11/01/2023 - 11/30/2023 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 11/1/23 20.6 1-Th 11/2/23 20.9 1-F 11/3/23 20.7 1-Sa 11/4/23 21.4 2-Su 11/5/23 21.7 2-M 11/6/23 22.1 2-T 11/7/23 22.5 2-W 11/8/23 21.3 2-Th 11/9/23 20.5 2-F 11/10/23 21.2 2-Sa 11/11/23 22.5 3-Su 11/12/23 21.5 3-M 11/13/23 21.4 3-T 11/14/23 20.8 3-W 11/15/23 20.9 3-Th 11/16/23 20.4 3-F 11/17/23 19.8 3-Sa 11/18/23 20.3 4-Su 11/19/23 21.7 4-M 11/20/23 20.7 4-T 11/21/23 20.3 4-W 11/22/23 20.3 4-Th 11/23/23 20.8 4-F 11/24/23 20.6 4-Sa 11/25/23 18.2 5-Su 11/26/23 16.1 5-M 11/27/23 13.8 5-T 11/28/23 17.4 5-W 11/29/23 18.0 5-Th 11/30/23 21.1 Average Monthly 20.3167 Report Only Monthly Total 609.7 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.

Signature Date

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-24-011 DIC: 1316.20 DATE:

January 11, 2024 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

Columbia Generating Station December 2023 NPDES Discharge Monitoring Report

REFERENCE:

NPDES Permit No. WA 002515-1 Condition S3.A Please find attached the NPDES Discharge Monitoring Report (DMR) for December 2023.

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, December 2023 KRB

Columbia Generating Station Page 2 of 2 February 26, 2024 Columbia Generating Station December 2023 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:12/01/2023 - 12/31/2023 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 12/1/23 3.1 7.7 7.8 0.03 23.5 1-Sa 12/2/23 3.0 7.7 7.8 0.03 24.8 2-Su 12/3/23 3.0 7.7 7.8 0.05 23.7 2-M 12/4/23 1.1 7.7 8.1 0

0.05

<0.1*

23.2 2-T 12/5/23 2.8 7.7 7.8 0.03 26.8 2-W 12/6/23 2.8 7.7 7.7 0.03 28.5 3.8*

23.8*

2-Th 12/7/23 2.8 7.7 7.8 0.03 27.3 2-F 12/8/23 2.8 7.7 7.8 0.01 26.6 2-Sa 12/9/23 2.9 7.7 7.8 0.01 23.5 3-Su 12/10/23 2.9 7.6 7.7 0.04 23.6 3-M 12/11/23 2.8 7.6 7.7 0.03 22.8 3-T 12/12/23 2.8 7.6 7.7 0.03 22.6 3-W 12/13/23 2.8 7.5 7.6 0.04 23.9 3-Th 12/14/23 2.8 7.6 7.8 0.03 23.2*

3-F 12/15/23 2.8 7.6 7.7 0.01 24.2*

3-Sa 12/16/23 2.8 7.6 7.7 0.01 24.1 4-Su 12/17/23 2.8 7.6 7.7 0.01 23.5 4-M 12/18/23 2.8 7.6 7.7 0.01 23.3*

4-T 12/19/23 2.7 7.6 7.7 0.01 25.9*

4-W 12/20/23 2.8 7.6 7.7 0.01 24.8 4-Th 12/21/23 2.7 7.6 7.7 0.01 24.8 4-F 12/22/23 2.7 7.7 7.7 0.01 24.0 4-Sa 12/23/23 2.7 7.7 7.8 0.01 23.6 5-Su 12/24/23 2.7 7.7 7.8 0.01 23.3 5-M 12/25/23 2.7 7.7 7.8 0.01 23.2 5-T 12/26/23 2.7 7.7 7.7 0.01 23.1 5-W 12/27/23 2.7 7.7 7.7 0.05 23.5 5-Th 12/28/23 1.2 7.7 8.2 0

0.01

<0.1*

23.2 5-F 12/29/23 3.1 8.1 8.3 0.01 23.6 5-Sa 12/30/23 3.1 8.1 8.3 0.01 23.3 6-Su 12/31/23 3.1 8.0 8.1 0.01 22.7 Daily Minimum 7.5 19.0

>= 6.5 (RO)

Report Only Average Monthly 2.7 3.8 23.8 Report Only

<= 5.6

<= 8.2

<= 53 Report Only Daily Maximum 3.1 8.3 0.05 28.5 3.8 23.8

<= 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) 12/4/2023 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) 12/28/2023 Bl<0.1 Grab sample verification of TRH <0.1 prior to resuming blowdown.

CWB Temperature Calculated Degrees C 12/14/2023 23.2 Data unavailable 12/14/23 1700 to 12/15/23 2000 due to maintenance outage. Daily maximum for 12/14/23 calculated from 12/14/23 0000-1600 CWB Temperature Calculated Degrees C 12/15/2023 24.2 Data unavailable 12/14/23 1700 to 12/15/23 2000 due to maintenance outage. Daily maximum for 12/15/23 calculated from 12/15/23 2100-2359 CWB Temperature Calculated Degrees C 12/18/2023 23.3 Data unavailable 12/18/23 2100 to 12/19/23 0800 due to maintenance outage. Daily maximum for 12/18/23 calculated from 12/18/23 0000-2000 CWB Temperature Calculated Degrees C 12/19/2023 25.9 Data unavailable 12/18/23 2100 to 12/19/23 0800 due to maintenance outage. Daily maximum for 12/19/23 calculated from 12/19/23 0900-2359 CWB Chromium Total Micrograms/L (ug/L) 12/6/2023 3.8 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 12/5/23-12/6/23 CWB Zinc Total Micrograms/L (ug/L) 12/6/2023 23.8 Result from 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> composite collected 12/5/23-12/6/23 SSWD All Parameters C

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 3 of 4 Monitoring Period:12/01/2023 - 12/31/2023 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 12/1/23 19.9 1-Sa 12/2/23 21.9 2-Su 12/3/23 21.2 2-M 12/4/23 19.0 2-T 12/5/23 21.7 2-W 12/6/23 22.0 2-Th 12/7/23 21.7 2-F 12/8/23 21.0 2-Sa 12/9/23 19.5 3-Su 12/10/23 13.3 3-M 12/11/23 13.7 3-T 12/12/23 14.0 3-W 12/13/23 15.8 3-Th 12/14/23 19.8*

3-F 12/15/23 22.5*

3-Sa 12/16/23 19.7 4-Su 12/17/23 20.6 4-M 12/18/23 20.0*

4-T 12/19/23 20.8*

4-W 12/20/23 20.9 4-Th 12/21/23 20.4 4-F 12/22/23 20.4 4-Sa 12/23/23 20.6 5-Su 12/24/23 19.5 5-M 12/25/23 19.6 5-T 12/26/23 20.1 5-W 12/27/23 20.4 5-Th 12/28/23 18.1 5-F 12/29/23 20.6 5-Sa 12/30/23 20.0 6-Su 12/31/23 20.0 Average Monthly 19.6 Report Only Monthly Total 608.6 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 12/14/2023 19.8 Data unavailable 12/14/23 1700 to 12/15/23 2000 due to maintenance outage. Daily average for 12/14/23 calculated from 12/14/23 0000-1600 Intk Flow MGD 12/15/2023 22.5 Data unavailable 12/14/23 1700 to 12/15/23 2000 due to maintenance outage. Daily average for 12/15/23 calculated from 12/15/23 2100-2359 Intk Flow MGD 12/18/2023 20.0 Data unavailable 12/18/23 2100 to 12/19/23 0800 due to maintenance outage. Daily average for 12/18/23 calculated from 12/18/23 0000-2000 Version: 1

Washington State Department of Ecology Discharge Monitoring Report (DMR)

Page: 4 of 4 Intk Flow MGD 12/19/2023 20.8 Data unavailable 12/18/23 2100 to 12/19/23 0800 due to maintenance outage. Daily average for 12/19/23 calculated from 12/19/23 0900-2359 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 1/11/2024 10:59:33 AM

P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-033 DIC: 409.3 DATE:

March 15, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

COLUMBIA GENERATING STATION ACUTE TOXICITY BIOASSAY FOR THE 1st QUARTER 2023

REFERENCE:

NPDES Permit No. WA 002515-1, Condition S13 Please find attached the acute toxicity bioassay report for Columbia Generating Station for the first quarter of calendar year 2023. The testing was conducted in accordance with condition S13 of Columbias National Pollutant Discharge Elimination System (NPDES) permit. The bioassay results are favorable with no acute toxicity detected in the test concentration representing the acute critical effluent concentration (ACEC; the ACEC equals 11% effluent). In fact, the results show 100%

survival of the test species, Pimephales promelas, in the 100% effluent sample.

A copy of the report (*.pdf format) and supporting statistical analysis (*.mdb format) will be submitted electronically to the State of Washington Department of Ecology (Ecology) and the Energy Facility Site Evaluation Council (EFSEC) via Ecologys Water Quality Permitting Portal (WQWebPortal).

If you have any questions concerning this information, please contact Marshall Schmitt at (509) 372-5334.

KRB

Attachment:

Acute Toxicity Test Report

Columbia Generating Station Page 2 of 2 March 15, 2023 CGS Acute Toxicity Bioassay Report for the 1st Quarter 2023 DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

FILE COPY Docket File PE20 M Schmitt PE03 Columbia Files 964Y K Byers 1025 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, Environmental Technician, Environmental Services Reviewed by: Marshall Schmitt, Environmental Scientist, E&RP Reviewed by: Matthew Turner, Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

AQUATIC TOXICOLOGY REPORT Project Name:

ENERGY NORTHWEST Location:

RICHLAND, WASHINGTON Prepared by:

Eurofins Environment Testing Northwest, LLC (aka Eurofins TestAmerica - ASL) 1100 NE Circle Boulevard, Suite 310 Corvallis, Oregon 97330 541-243-6137 Accredited in accordance with NELAP Oregon Environmental Laboratory Accreditation Program #OR100022 (NELAP)

State of Washington DOE Environmental Laboratory Accreditation Program, Lab ID C556 California State Environmental Laboratory Accreditation Program, Certificate No.: 1726 Report Date: February 23, 2023 Released by: Michelle Bennett Lab I.D. No. B5558 This report is issued solely for the use of the person or company to whom it is addressed. Any use, copying or disclosure other than by the intended recipient is unauthorized. If you have received this report in error, please notify the sender and destroy this report immediately. This report shall not be reproduced except in full, without prior express written approval by the laboratory.

Results relate only to the items tested and the sample(s) as received by the laboratory. The results included in this report have been reviewed for compliance and meet all requirements for accredited parameters. All data have been found to be compliant with laboratory protocol, with the exception of any items noted in this report. For questions, please contact the Project Manager (contact info on next page).

Energy NW B5558.pdf Page 1 of 25

CONTENTS Section Page INTRODUCTION.................................................................................................................. 3 OVERVIEW OF REGULATORY GUIDANCE................................................................... 3

SUMMARY

OF TEST RESULTS......................................................................................... 4 ACRONYM DEFINITIONS...................................................................................... 4 SAMPLE INFORMATION..................................................................................................... 5 METHODS AND MATERIALS............................................................................................ 5 TEST METHODS....................................................................................................... 5 DEVIATIONS FROM PROTOCOLS........................................................................ 6 TEST DESIGN........................................................................................................... 6 DILUTION WATER.................................................................................................. 6 SAMPLE COLLECTION AND STORAGE.............................................................. 6 SAMPLE PREPARATION........................................................................................ 7 DATA ANALYSIS..................................................................................................... 7 RESULTS AND DISCUSSION............................................................................................. 8 REFERENCE TOXICANT TESTS........................................................................... 9 APPENDIX A. RAW DATA SHEETS APPENDIX B. REFERENCE TOXICANT DATA SHEETS APPENDIX C. CHAIN OF CUSTODY LABORATORY CONTACT: Brett Muckey, Business Unit Manager (BUMa)

Brett.Muckey@et.eurofinsus.com (541) 243-0980 Energy NW B5558.pdf Page 2 of 25

INTRODUCTION Eurofins Environment Testing Northwest, LLC Applied Sciences Laboratory (EETNW - ASL) conducted toxicity testing on sample(s) from Energy Northwest, Richland, Washington.

Testing was initiated on: February 8, 2023 The test(s) were conducted using:

• the fathead minnow (Pimephales promelas)

OVERVIEW OF REGULATORY GUIDANCE The following provides an overview and excerpts of applicable permit specifics, regulatory guidance, and other relevant information. This is intended only as a helpful guide, from a laboratory perspective, for understanding test outcomes. The final responsibility for interpretation of results remains with the client and/or regulatory agency.

The following guidance is taken from EETNW-ASLs reading of the NPDES permit for Energy Northwests Columbia Generating Station in Richland, WA (permit #WA002515-1, effective Nov 1, 2014, expires Oct 31, 2019, modified Feb 8, 2016, and Mar. 19, 2019).

Acute toxicity:

• Effluent Limit for Acute Toxicity:

o No acute toxicity detected in a test concentration representing the acute critical effluent concentration (ACEC).

o The ACEC equals 11% effluent.

• Compliance with the Effluent Limit for Acute Toxicity:

o Compliance with the effluent limit for acute toxicity means the result of the testing show no statistically significant difference in survival between the control and the ACEC.

o The Permittee must determine the statistical significance by conducting a hypothesis test at the 0.05 level of significance (i.e. alpha = 0.05) o If the difference in survival between the control and the ACEC is less than 10 percent, the Permittee must conduct the hypothesis test at the 0.01 level of significance.

o If the test results show a statistically significant difference in survival between the control and the ACEC, and EFSEC has not determined the test result to be anomalous under Section D, and the test is otherwise valid, the result is a violation of the effluent limit for acute toxicity.

• Compliance Testing for Acute Toxicity:

o Conduct quarterly acute toxicity testing on the final effluent. (Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec) o using each of the species and protocols listed on a rotating basis.

Response to Noncompliance With an Effluent Limit for Acute Toxicity:

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o If a toxicity test determines a statistically significant difference in response between the ACEC and the control, the Permittee must begin additional compliance monitoring within one week of receiving the test results.

• Sampling and Reporting Requirements:

o The permittee must collect grab samples must cool the samples to 0 - 6 degrees Celsius during collection and send them to the lab immediately upon completion.

o The lab must begin the toxicity testing no later than 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> after sampling was completed.

o The Permittee must chemically dechlorinate final effluent with sodium thiosulfate just prior to test initiation. Do not add more sodium thiosulfate than is necessary to neutralize the chlorine. Provide in the test report the calculations to determine the amount of sodium thiosulfate necessary The following is taken from the WDOE guidance (WQ-R-95-80, June 2016 revision):

• To reduce WET limit violations (and anomalous concentration-response relationships) due to statistical significance that is a Type I error [false positive], we lower alpha when differences in test organism response are small.

• Alpha will be lowered from 0.05 to 0.01 if a 10% difference in an acute test is significant

SUMMARY

OF TEST RESULTS Exhibit 1 provides a summary of the final test results.

EXHIBIT 1 Summary of Acute Test Results Species NOEC

(%)

LOEC

(%)

LC50

(%)

Was a statistically significant difference between control and ACEC shown?

P. promelas 100

> 100

> 100 No Note: acronyms are as defined below.

From the NPDES permit - Effluent Limit for Acute Toxicity: Compliance with the effluent limit for acute toxicity means the result of the testing show no statistically significant difference in survival between the control and the ACEC. [ACEC = 11%].

More detailed information is provided in the Results and Discussion section.

ACRONYM DEFINITIONS (from EPA guidance):

NOEC = No Observed Effect Concentration: The highest test concentration that causes no observable adverse effects on the test organisms (i.e. no statistically significant reduction from the control).

Energy NW B5558.pdf Page 4 of 25

LOEC = Low Observed Effect Concentration: The lowest test concentration that does cause an observable adverse effect on the test organisms (i.e. is statistically significant reduction from the control).

LC50 = Lethal Concentration (50%): A point estimate of the test concentration that would cause death in 50 percent of the test population.

SAMPLE INFORMATION Exhibit 2 provides a summary of the sample conditions as received.

EXHIBIT 2 Sample Conditions on Receipt Sample ID 230729-01 EETNW - ASL SDG B5558-01 Collection - Date and Time 02/07/2023 07:06 Receipt - Date and Time 02/08/2023 14:35 Temperature (oC) 5.0 Dissolved Oxygen (mg/L) 8.9 pH 8.0 Conductivity (S/cm) 1078 Total Residual Chlorine (mg/L)

< 0.02 Ammonia (mg/L as NH3-N) 0.11 Total Hardness (mg/L as CaCO3) 533 Total Alkalinity (mg/L as CaCO3) 133 METHODS AND MATERIALS TEST METHODS The acute test methods were performed according to: Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, USEPA Office of Water (2002), EPA-821-R-02-012.

Additional guidance was provided by:

• Whole Effluent Toxicity Testing Guidance and Test Review Criteria, Washington State Department of Ecology (revised Jun 2016) Pub# WQ-R-95-80.

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DEVIATIONS FROM PROTOCOLS Deviations from required procedures in the test methods:

• None noted.

Deviations from recommended procedures in the test methods:

• None noted.

TEST DESIGN The following summarizes the conditions used for both overall testing and the specifics for each test (observations and notations can be found on the datasheets in Appendix A):

Overall Test Design:

• Acute test: 6.25, 11.0 [ACEC], 25.0, 50.0, and 100 percent sample + dilution water for the control.

Test Organism Conditions:

• All organisms tested were fed and maintained during culturing, acclimation, and testing as prescribed by the EPA (2002).

• The test organisms appeared vigorous and in good condition prior to testing.

P. promelas acute test (renewal):

• Source: Aquatox Inc., Hot Springs, Arkansas

• Age: 1 to 14 days old, within a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> age range

• Design: Four test vessels per concentration, Ten organisms per vessel

• Test Solution Renewal: Once @ 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> (i.e. static-renewal test)

• Monitoring:

o Daily: Survival, DO, pH, and temperature; all concentrations.

o Pre and Post Renewal solutions: DO and pH, all concentrations.

o Test Initiation, with each new sample use, and Termination:

Conductivity, all concentrations (WDOE)

• Termination: 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />.

• Endpoints: Survival (at termination)

DILUTION WATER The dilution water used was the standard culture water used by EETNW - ASL:

• Reconstituted, moderately hard water (as per EPA protocol) with a total hardness of 75 to 105 mg/L as CaCO3 and an alkalinity of 50 to 75 mg/L as CaCO3.

SAMPLE COLLECTION AND STORAGE Samples were collected by Energy Northwest personnel. The samples were accepted as scheduled by EETNW - ASL. Chain of Custody and Sample Receipt Records are provided in Appendix C.

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• The sample was received within the EPA recommended 0 to 6 oC range.

• The sample was received within the WDOE required 0 to 6 oC range.

• The sample was initially used for test initiation or test solution renewal within the EPA recommended maximum holding time of 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> of sample collection.

• All subsequent uses of the sample occurred within the EPA recommended maximum holding time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> past the time of initial use of that sample.

• All subsequent uses of a sample occurred within the WDOE recommended maximum holding time of 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> past the time of sample collection. (For renewals of a 96 hour0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> duration acute test)

• Following receipt, the samples were stored in the dark at 0 to 6 C until test solutions were prepared and tested.

SAMPLE PREPARATION Samples used during these tests were:

• Temperature adjusted prior to test initiation and each daily renewal.

• As no Total Residual Chlorine was observed, dechlorination with sodium thiosulfate was not performed.

DATA ANALYSIS The statistical analyses performed for the acute tests were those outlined in Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, USEPA Office of Water, Fifth Edition (2002), EPA-821-R-02-012, using CETIS.

• The specific statistical analysis and CETIS version used for each endpoint evaluation is listed with the statistical outputs included with each test in Appendix A.

• If any additional analysis methods were also used, an explanation of the rationale and reference to the source method is included with the presentation of those results below.

Additional guidance was provided by:

• Whole Effluent Toxicity Testing Guidance and Test Review Criteria, Washington State Department of Ecology (revised Jun 2016) Pub# WQ-R-95-80.

Energy NW B5558.pdf Page 7 of 25

RESULTS AND DISCUSSION The raw data sheets for all tests are presented in Appendix A.

ACUTE BIOASSAYS Table 1 summarizes the survival data for the P. promelas acute test.

Table 1 Summary of Acute Results P. promelas Sample Concentration

(%)

Percent Survival (at Test Termination)

Control 92.5 6.25 100 11.0 97.5 25.0 100 50.0 100 100 100 Statistical analysis in accordance with the EPA protocol and WDOE guidance results in:

• NOEC = 100 %

• LOEC > 100 %

• LC50 > 100 %

From the NPDES permit - Effluent Limit for Acute Toxicity: Compliance with the effluent limit for acute toxicity means the result of the testing show no statistically significant difference in survival between the control and the ACEC. [ACEC = 11%].

• No statistically significant difference between control and ACEC was shown.

Dissolved oxygen concentrations remained at 4.0 mg/L or greater throughout the test period.

Test temperatures remained in the range of 20+/-1 C.

The P. promelas acute test meets Test Acceptability Criteria (TAC) of a minimum 90 percent control survival. Unless referenced above, the tests proceeded without any noted deviations or interruptions that could have affected test results. The testing should be considered valid.

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REFERENCE TOXICANT TESTS Reference toxicant (reftox) testing is performed to document both initial and ongoing laboratory performance of the test method(s). While the health of the test organisms is primarily evaluated by the performance of the laboratory control, reftox test results also may be used to assess the health and sensitivity of the test organisms. Reftox test results within their respective cumulative summary (Cusum) chart limits are indicative of consistent laboratory performance and normal test organism sensitivity.

The results of the reftox tests indicate that the test organisms were within their respective cusum chart limits based on EPA guidelines. This demonstrates ongoing laboratory proficiency of the test methods and suggests normal test organism sensitivity in the associated client testing.

The P. promelas acute reftox test was conducted using sodium chloride. The data sheets for the reference toxicant tests are provided in Appendix B.

Table 2 summarizes the reference toxicant test results and Cusum chart limits.

Table 2 Acute Reference Toxicant Tests (g/L)

Species LC50 Cusum Chart Limits P. promelas 7.1 6.5 to 8.9 Energy NW B5558.pdf Page 9 of 25

APPENDIX A RAW DATA SHEETS Energy NW B5558.pdf Page 10 of 25

0.11 533 133 Energy NW B5558.pdf Page 11 of 25

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APPENDIX B REFERENCE TOXICANT DATA SHEETS Energy NW B5558.pdf Page 20 of 25

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APPENDIX C CHAIN OF CUSTODY Energy NW B5558.pdf Page 23 of 25

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P.O. Box 968 / Richland, WA 99352-0968 / (509) 372-5000 / www.energy-northwest.com INTEROFFICE MEMO GO2-23-081 DIC: 409.3 DATE:

July 18, 2023 TO:

Columbia Generating Station, (CGS)

FROM:

Kris Byers, Environmental Scientist (1025)

SUBJECT:

COLUMBIA GENERATING STATION ACUTE TOXICITY BIOASSAY FOR THE 2nd QUARTER 2023

REFERENCE:

NPDES Permit No. WA 002515-1, Condition S13 Please find attached the acute toxicity bioassay report for Columbia Generating Station for the second quarter of calendar year 2023. The testing was conducted in accordance with condition S13 of Columbias National Pollutant Discharge Elimination System (NPDES) permit. The bioassay results are favorable with no acute toxicity detected in the test concentration representing the acute critical effluent concentration (ACEC; the ACEC equals 11% effluent). In fact, the results show 100%

survival of the test species, Ceriodaphnia dubia, in the 100% effluent sample.

A copy of the report (*.pdf format) and supporting statistical analysis (*.mdb format) will be submitted electronically to the State of Washington Department of Ecology (Ecology) and the Energy Facility Site Evaluation Council (EFSEC) via Ecologys Water Quality Permitting Portal (WQWebPortal).

If you have any questions concerning this information, please contact Denis Mehinagic at (509) 372-5768.

KRB

Attachment:

Acute Toxicity Test Report

Columbia Generating Station Page 2 of 2 July 18, 2023 CGS Acute Toxicity Bioassay Report for the 2nd quarter 2023 DISTRIBUTION LIST:

INTERNAL DISTRIBUTION:

FILE COPY Docket File PE20 D. Mehinagic PE03 Columbia Files 964Y K Byers 1025 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, Environmental Technician, Environmental Services Reviewed by: Denis Mehinagic, Environmental Scientist, E&RP Reviewed by: Matthew Turner, Manager, Environmental Services Approved by: Mary Joy C. Ramos, Manager, Environmental & Regulatory Programs

AQUATIC TOXICOLOGY REPORT Project Name:

ENERGY NORTHWEST Location:

RICHLAND, WASHINGTON Prepared by:

Eurofins Environment Testing Northwest, LLC (aka TestAmerica - ASL) 1100 NE Circle Boulevard, Suite 310 Corvallis, Oregon 97330 541-243-6137 Accredited in accordance with NELAP Oregon Environmental Laboratory Accreditation Program #OR100022 (NELAP)

State of Washington DOE Environmental Laboratory Accreditation Program, Lab ID C556 California State Environmental Laboratory Accreditation Program, Certificate No.: 1726 Report Date: June 29, 2023 Released by: Michelle Bennett Lab I.D. No. B5656 This report is issued solely for the use of the person or company to whom it is addressed. Any use, copying or disclosure other than by the intended recipient is unauthorized. If you have received this report in error, please notify the sender and destroy this report immediately. This report shall not be reproduced except in full, without prior express written approval by the laboratory.

Results relate only to the items tested and the sample(s) as received by the laboratory. The results included in this report have been reviewed for compliance and meet all requirements for accredited parameters. All data have been found to be compliant with laboratory protocol, with the exception of any items noted in this report. For questions, please contact the Project Manager (contact info on next page).

Energy NW B5656.pdf Page 1 of 24

CONTENTS Section Page INTRODUCTION.................................................................................................................. 3 OVERVIEW OF REGULATORY GUIDANCE................................................................... 3

SUMMARY

OF TEST RESULTS......................................................................................... 4 ACRONYM DEFINITIONS...................................................................................... 4 SAMPLE INFORMATION..................................................................................................... 5 METHODS AND MATERIALS............................................................................................ 6 TEST METHODS....................................................................................................... 6 DEVIATIONS FROM PROTOCOLS........................................................................ 6 TEST DESIGN........................................................................................................... 6 DILUTION WATER.................................................................................................. 7 SAMPLE COLLECTION AND STORAGE.............................................................. 7 SAMPLE PREPARATION........................................................................................ 7 DATA ANALYSIS..................................................................................................... 7 RESULTS AND DISCUSSION............................................................................................. 8 REFERENCE TOXICANT TESTS........................................................................... 9 APPENDIX A. RAW DATA SHEETS APPENDIX B. REFERENCE TOXICANT DATA SHEETS APPENDIX C. CHAIN OF CUSTODY LABORATORY CONTACT: Brett Muckey, Business Unit Manager (BUMa)

Brett.Muckey@et.eurofinsus.com (541) 243-0980 Energy NW B5656.pdf Page 2 of 24

INTRODUCTION Eurofins Environment Testing Northwest, LLC Applied Sciences Laboratory (EETNW - ASL) conducted toxicity testing on sample(s) from Energy Northwest, Richland, Washington.

Testing was initiated on: June 7, 2023 The test(s) were conducted using:

• the water flea (Ceriodaphnia dubia)

OVERVIEW OF REGULATORY GUIDANCE The following provides an overview and excerpts of applicable permit specifics, regulatory guidance, and other relevant information. This is intended only as a helpful guide, from a laboratory perspective, for understanding test outcomes. The final responsibility for interpretation of results remains with the client and/or regulatory agency.

The following guidance is taken from EETNW-ASLs reading of the NPDES permit for Energy Northwests Columbia Generating Station in Richland, WA (permit #WA0025151, effective Nov 1, 2014, expires Oct 31, 2019, modified Feb 8, 2016, and Mar. 19, 2019).

Acute toxicity:

• Effluent Limit for Acute Toxicity:

o No acute toxicity detected in a test concentration representing the acute critical effluent concentration (ACEC).

o The ACEC equals 11% effluent.

• Compliance with the Effluent Limit for Acute Toxicity:

o Compliance with the effluent limit for acute toxicity means the result of the testing show no statistically significant difference in survival between the control and the ACEC.

o The Permittee must determine the statistical significance by conducting a hypothesis test at the 0.05 level of significance (i.e. alpha = 0.05) o If the difference in survival between the control and the ACEC is less than 10 percent, the Permittee must conduct the hypothesis test at the 0.01 level of significance.

o If the test results show a statistically significant difference in survival between the control and the ACEC, and EFSEC has not determined the test result to be anomalous under Section D, and the test is otherwise valid, the result is a violation of the effluent limit for acute toxicity.

• Compliance Testing for Acute Toxicity:

o Conduct quarterly acute toxicity testing on the final effluent. (Jan-Mar, Apr-Jun, Jul-Sep, Oct-Dec) o using each of the species and protocols listed on a rotating basis.

Response to Noncompliance With an Effluent Limit for Acute Toxicity:

Energy NW B5656.pdf Page 3 of 24

o If a toxicity test determines a statistically significant difference in response between the ACEC and the control, the Permittee must begin additional compliance monitoring within one week of receiving the test results.

• Sampling and Reporting Requirements:

o The permittee must collect grab samples must cool the samples to 0 - 6 degrees Celsius during collection and send them to the lab immediately upon completion.

o The lab must begin the toxicity testing no later than 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> after sampling was completed.

o The Permittee must chemically dechlorinate final effluent with sodium thiosulfate just prior to test initiation. Do not add more sodium thiosulfate than is necessary to neutralize the chlorine. Provide in the test report the calculations to determine the amount of sodium thiosulfate necessary The following is taken from the WDOE guidance (WQ-R-95-80, June 2016 revision):

• To reduce WET limit violations (and anomalous concentration-response relationships) due to statistical significance that is a Type I error [false positive], we lower alpha when differences in test organism response are small.

• Alpha will be lowered from 0.05 to 0.01 if a 10% difference in an acute test is significant

SUMMARY

OF TEST RESULTS Exhibit 1 provides a summary of the final test results.

EXHIBIT 1 Summary of Acute Test Results Species NOEC

(%)

LOEC

(%)

LC50

(%)

Was a statistically significant difference between control and ACEC shown?

C. dubia 100

> 100

> 100 No Note: acronyms are as defined below.

From the NPDES permit - Effluent Limit for Acute Toxicity: Compliance with the effluent limit for acute toxicity means the result of the testing show no statistically significant difference in survival between the control and the ACEC. [ACEC = 11%].

More detailed information is provided in the Results and Discussion section.

ACRONYM DEFINITIONS (from EPA guidance):

NOEC = No Observed Effect Concentration: The highest test concentration that causes no observable adverse effects on the test organisms (i.e. no statistically significant reduction from the control).

Energy NW B5656.pdf Page 4 of 24

LOEC = Low Observed Effect Concentration: The lowest test concentration that does cause an observable adverse effect on the test organisms (i.e. is statistically significant reduction from the control).

LC50 = Lethal Concentration (50%): A point estimate of the test concentration that would cause death in 50 percent of the test population.

SAMPLE INFORMATION Exhibit 2 provides a summary of the sample conditions as received.

EXHIBIT 2 Sample Conditions on Receipt Sample ID 231092-01 EETNW - ASL SDG B5656-01 Collection - Date and Time 06/06/2023 06:50 Receipt - Date and Time 06/07/2023 12:22 Temperature (oC) 1.4 Dissolved Oxygen (mg/L) 10.5 pH 7.4 Conductivity (S/cm) 215 Total Residual Chlorine (mg/L)

< 0.02 Ammonia (mg/L as NH3-N)

< 0.10 Total Hardness (mg/L as CaCO3) 83 Total Alkalinity (mg/L as CaCO3) 56 Energy NW B5656.pdf Page 5 of 24

METHODS AND MATERIALS TEST METHODS The acute test methods were performed according to: Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, USEPA Office of Water (2002), EPA-821-R-02-012.

Additional guidance was provided by:

• Whole Effluent Toxicity Testing Guidance and Test Review Criteria, Washington State Department of Ecology (revised Jun 2016) Pub# WQ-R-95-80.

DEVIATIONS FROM PROTOCOLS Deviations from required procedures in the test methods:

• None noted.

Deviations from recommended procedures in the test methods:

• None noted.

TEST DESIGN The following summarizes the conditions used for both overall testing and the specifics for each test (observations and notations can be found on the datasheets in Appendix A):

Overall Test Design:

• Acute test: 6.25, 11.0 [ACEC], 25.0, 50.0, and 100 percent sample + dilution water for the control.

Test Organism Conditions:

• All organisms tested were fed and maintained during culturing, acclimation, and testing as prescribed by the EPA (2002).

• The test organisms appeared vigorous and in good condition prior to testing.

C. dubia acute test: (WDOE)

• Source: EETNW-ASL's in-house cultures

• Age: Less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> old

• Design: Four test vessels per concentration, five organisms per vessel

• Test Solution Renewal: None (i.e. static test)

• Monitoring:

o Daily: Survival, DO, pH, and temperature; all concentrations.

o Test Initiation and Termination: Conductivity, all concentrations

• Termination: 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

• Endpoints: Survival (at termination).

Energy NW B5656.pdf Page 6 of 24

DILUTION WATER The dilution water used was the standard culture water used by EETNW - ASL:

• Reconstituted, moderately hard water (as per EPA protocol) with a total hardness of 75 to 105 mg/L as CaCO3 and an alkalinity of 50 to 75 mg/L as CaCO3.

SAMPLE COLLECTION AND STORAGE Samples were collected by Energy Northwest personnel. The samples were accepted as scheduled by EETNW - ASL. Chain of Custody and Sample Receipt Records are provided in Appendix C.

• The sample was received within the EPA recommended 0 to 6 oC range.

• The sample was received within the WDOE required 0 to 6 oC range.

• The sample was initially used for test initiation or test solution renewal within the EPA recommended maximum holding time of 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> of sample collection.

• All subsequent uses of the sample occurred within the EPA recommended maximum holding time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> past the time of initial use of that sample.

• All subsequent uses of a sample occurred within the WDOE recommended maximum holding time of 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> past the time of sample collection. (For renewals of a 96 hour0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> duration acute test)

• Following receipt, the samples were stored in the dark at 0 to 6 C until test solutions were prepared and tested.

SAMPLE PREPARATION Samples used during these tests were:

• Temperature adjusted prior to test initiation and each daily renewal.

• As no Total Residual Chlorine was observed, dechlorination with sodium thiosulfate was not performed.

DATA ANALYSIS The statistical analyses performed for the acute tests were those outlined in Methods for Measuring the Acute Toxicity of Effluents and Receiving Waters to Freshwater and Marine Organisms, USEPA Office of Water, Fifth Edition (2002), EPA-821-R-02-012, using CETIS.

• The specific statistical analysis and CETIS version used for each endpoint evaluation is listed with the statistical outputs included with each test in Appendix A.

• If any additional analysis methods were also used, an explanation of the rationale and reference to the source method is included with the presentation of those results below.

Additional guidance was provided by:

• Whole Effluent Toxicity Testing Guidance and Test Review Criteria, Washington State Department of Ecology (revised Jun 2016) Pub# WQ-R-95-80.

Energy NW B5656.pdf Page 7 of 24

RESULTS AND DISCUSSION The raw data sheets for all tests are presented in Appendix A.

ACUTE BIOASSAYS Table 1 summarizes the survival data for the C. dubia acute test.

Table 1 Summary of Acute Results C. dubia Sample Concentration

(%)

Percent Survival (at Test Termination)

Control 100 6.25 100 11.0 100 25.0 100 50.0 100 100 100 Statistical analysis in accordance with the EPA protocol and WDOE guidance results in:

• NOEC = 100 %

• LOEC > 100 %

• LC50 > 100 %

From the NPDES permit - Effluent Limit for Acute Toxicity: Compliance with the effluent limit for acute toxicity means the result of the testing show no statistically significant difference in survival between the control and the ACEC. [ACEC = 11%].

• No statistically significant difference between control and ACEC was shown.

Dissolved oxygen concentrations remained at 4.0 mg/L or greater throughout the test period.

Test temperatures remained in the range of 20+/-1 C.

The C. dubia acute test meets Test Acceptability Criteria (TAC) of a minimum 90 percent control survival. Unless referenced above, the tests proceeded without any noted deviations or interruptions that could have affected test results. The testing should be considered valid.

Energy NW B5656.pdf Page 8 of 24

REFERENCE TOXICANT TESTS Reference toxicant (reftox) testing is performed to document both initial and ongoing laboratory performance of the test method(s). While the health of the test organisms is primarily evaluated by the performance of the laboratory control, reftox test results also may be used to assess the health and sensitivity of the test organisms. Reftox test results within their respective cumulative summary (Cusum) chart limits are indicative of consistent laboratory performance and normal test organism sensitivity.

The results of the reftox tests indicate that the test organisms were within their respective cusum chart limits based on EPA guidelines. This demonstrates ongoing laboratory proficiency of the test methods and suggests normal test organism sensitivity in the associated client testing.

The C. dubia reftox test was conducted using sodium chloride. The data sheets for the reference toxicant test are provided in Appendix B.

Table 2 summarizes the reference toxicant test results and Cusum chart limits.

Table 2 Acute Reference Toxicant Test with Sodium Chloride (g/L)

Species LC50 Control Chart C. dubia 2.46 1.99 to 2.77 Energy NW B5656.pdf Page 9 of 24

APPENDIX A RAW DATA SHEETS Energy NW B5656.pdf Page 10 of 24

<0.10 83 56 Energy NW B5656.pdf Page 11 of 24

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CETIS Summary Report Report Date:

12 Jun-23 07:26 (p 1 of 1)

Test Code/ID:

B565601cda / 21-3391-0618 Ceriodaphnia 48-h Acute Survival Test Eurofins Environment Testing NW - ASL Batch ID:

18-3314-3584 Start Date:

07 Jun-23 14:22 Ending Date: 09 Jun-23 13:42 Test Type: Survival (48h)

Test Length: 47h Protocol:

EPA/821/R-02-012 (2002)

Diluent:

Mod-Hard Synthetic Water Brine:

Species:

Ceriodaphnia dubia Source:

In-House Culture Analyst:

Age: <24 Taxon:

Branchiopoda Sample ID:

13-5305-2030 Sample Date: 06 Jun-23 06:50 Receipt Date: 07 Jun-23 12:22 Code:

B5656-01 Sample Age: 32h (1.4 °C)

Source:

Energy Northwest (WA 0025151)

Station:

Client:

Project:

Material:

Unknown CAS (PC):

Multiple Comparison Summary NOEL LOEL TOEL Endpoint Analysis ID Comparison Method PMSD

S TU 100

>100 09-3198-1279 7.25%

48h Survival Rate 1

Steel Many-One Rank Sum Test 1

95% LCL 95% UCL Point Estimate Summary Endpoint Analysis ID Point Estimate Method Level

S TU EC50

>100 00-4116-3045

<1 Linear Interpolation (ICPIN) 48h Survival Rate 1

Test Acceptability Attribute Test Stat Decision Analysis ID Endpoint Lower Overlap Upper TAC Limits 1

00-4116-3045 0.9 Control Resp 48h Survival Rate Yes Passes Criteria 1

09-3198-1279 0.9 Control Resp 48h Survival Rate Yes Passes Criteria Code Mean Min Max Std Dev Count CV%

Std Err Conc-%

48h Survival Rate Summary 95% LCL 95% UCL

%Effect 0

1.0000 1.0000 1.0000 0.0000 4

0.0000 1.0000 1.0000 0.00%

D 6.25 1.0000 1.0000 1.0000 0.0000 4

0.0000 1.0000 1.0000 0.00%

11 1.0000 1.0000 1.0000 0.0000 4

0.0000 1.0000 1.0000 0.00%

25 1.0000 1.0000 1.0000 0.0000 4

0.0000 1.0000 1.0000 0.00%

50 1.0000 1.0000 1.0000 0.0000 4

0.0000 1.0000 1.0000 0.00%

100 1.0000 1.0000 1.0000 0.0000 4

0.0000 1.0000 1.0000 0.00%

Code Conc-%

48h Survival Rate Detail Rep 1 Rep 2 Rep 3 Rep 4 7C3CB5340F8C0CF602EDD7FB547CC89A MD5:

0 D

1.0000 1.0000 1.0000 1.0000 6.25 1.0000 1.0000 1.0000 1.0000 11 1.0000 1.0000 1.0000 1.0000 25 1.0000 1.0000 1.0000 1.0000 50 1.0000 1.0000 1.0000 1.0000 100 1.0000 1.0000 1.0000 1.0000 Code Conc-%

48h Survival Rate Binomials Rep 1 Rep 2 Rep 3 Rep 4 0

D 5/5 5/5 5/5 5/5 6.25 5/5 5/5 5/5 5/5 11 5/5 5/5 5/5 5/5 25 2/2 5/5 5/5 5/5 50 5/5 5/5 5/5 5/5 100 5/5 5/5 5/5 5/5 CETIS' v1.9.7.7 007-238-492-3 QA:________

Analyst:________

Energy NW B5656.pdf Page 15 of 24

Report Date:

12 Jun-23 07:26 (p 1 of 2)

CETIS Analytical Report Test Code/ID:

B565601cda / 21-3391-0618 Ceriodaphnia 48-h Acute Survival Test Eurofins Environment Testing NW - ASL Analyzed:

12 Jun-23 7:25 Endpoint:

48h Survival Rate CETIS Version:

CETISv1.9.7 Analysis ID:

09-3198-1279 Analysis:

Nonparametric-Control vs Treatments Status Level:

1 Edit Date:

12 Jun-23 7:25 MD5 Hash: 7C3CB5340F8C0CF602EDD7FB547CC89 Editor ID:

007-238-492-3 Test Stat Critical P-Value Decision(:5%)

Ties vs Control Conc-%

Steel Many-One Rank Sum Test P-Type DF 18 10 1

0.8333 Non-Significant Effect 6.25 Dilution Water 6

CDF 18 10 1

0.8333 Non-Significant Effect 11 6

CDF 18 10 1

0.8333 Non-Significant Effect 25 6

CDF 18 10 1

0.8333 Non-Significant Effect 50 6

CDF 18 10 1

0.8333 Non-Significant Effect 100 6

CDF NOEL LOEL TU TOEL Alt Hyp Data Transform PMSD MSDu 100

>100 7.25%

1 C > T Angular (Corrected) 0.07255 ANOVA Table Source Sum Squares Mean Square DF F Stat P-Value Decision(:5%)

Between 0.0038451 0.0007690 5

1 0.4457 Non-Significant Effect Error 0.0138422 0.0007690 18 0.0176872 23 Total ANOVA Assumptions Tests Attribute Test Test Stat Critical P-Value Decision(:1%)

Indeterminate Bartlett Equality of Variance Test Variance 0.4634 0.884

<1.0E-05 Non-Normal Distribution Shapiro-Wilk W Normality Test Distribution Mean Min Max Median Count Code Std Err Conc-%

CV%

%Effect 95% LCL 95% UCL 48h Survival Rate Summary 1.0000 1.0000 1.0000 1.0000 0

4 0.0000 0.00%

0.00%

1.0000 1.0000 D

1.0000 1.0000 1.0000 1.0000 6.25 4

0.0000 0.00%

0.00%

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 11 4

0.0000 0.00%

0.00%

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 25 4

0.0000 0.00%

0.00%

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 50 4

0.0000 0.00%

0.00%

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 100 4

0.0000 0.00%

0.00%

1.0000 1.0000 Mean Min Max Median Count Code Std Err Conc-%

CV%

%Effect 95% LCL 95% UCL Angular (Corrected) Transformed Summary 1.3450 1.3450 1.3450 1.3450 0

4 0.0000 0.00%

0.00%

1.3450 1.3460 D

1.3450 1.3450 1.3450 1.3450 6.25 4

0.0000 0.00%

0.00%

1.3450 1.3460 1.3450 1.3450 1.3450 1.3450 11 4

0.0000 0.00%

0.00%

1.3450 1.3460 1.3110 1.2090 1.3450 1.3450 25 4

0.0340 5.18%

2.52%

1.2030 1.4190 1.3450 1.3450 1.3450 1.3450 50 4

0.0000 0.00%

0.00%

1.3450 1.3460 1.3450 1.3450 1.3450 1.3450 100 4

0.0000 0.00%

0.00%

1.3450 1.3460 CETIS' v1.9.7.7 007-238-492-3 QA:________

Analyst:________

Energy NW B5656.pdf Page 16 of 24

Report Date:

12 Jun-23 07:26 (p 2 of 2)

CETIS Analytical Report Test Code/ID:

B565601cda / 21-3391-0618 Ceriodaphnia 48-h Acute Survival Test Eurofins Environment Testing NW - ASL Analyzed:

12 Jun-23 7:25 Endpoint:

48h Survival Rate CETIS Version:

CETISv1.9.7 Analysis ID:

09-3198-1279 Analysis:

Nonparametric-Control vs Treatments Status Level:

1 Edit Date:

12 Jun-23 7:25 MD5 Hash: 7C3CB5340F8C0CF602EDD7FB547CC89 Editor ID:

007-238-492-3 CETIS' v1.9.7.7 007-238-492-3 QA:________

Analyst:________

Energy NW B5656.pdf Page 17 of 24

CETIS Analytical Report Report Date:

12 Jun-23 07:26 (p 1 of 1)

Test Code/ID:

B565601cda / 21-3391-0618 Ceriodaphnia 48-h Acute Survival Test Eurofins Environment Testing NW - ASL Analyzed:

12 Jun-23 7:25 Endpoint:

48h Survival Rate CETIS Version:

CETISv1.9.7 Analysis ID:

00-4116-3045 Analysis:

Linear Interpolation (ICPIN)

Status Level:

1 Edit Date:

12 Jun-23 7:25 MD5 Hash: 7C3CB5340F8C0CF602EDD7FB547CC89 Editor ID:

007-238-492-3 X Transform Y Transform Resamples Exp 95% CL Linear Interpolation Options Method Seed Log(X+1)

Linear 200 Yes Two-Point Interpolation 429353 Point Estimates Level 95% LCL 95% UCL TU 95% LCL 95% UCL EC50

>100

<1 Mean Min Max Count Code A/B Calculated Variate(A/B)

Conc-%

CV%

%Effect 48h Survival Rate Summary Mean

%Effect Isotonic Variate Median 1.0000 20/20 1.0000 1.0000 0

4 D

0.00%

0.00%

1.0000 0.00%

1.0000 1.0000 20/20 1.0000 1.0000 6.25 4

0.00%

0.00%

1.0000 0.00%

1.0000 1.0000 20/20 1.0000 1.0000 11 4

0.00%

0.00%

1.0000 0.00%

1.0000 1.0000 17/17 1.0000 1.0000 25 4

0.00%

0.00%

1.0000 0.00%

1.0000 1.0000 20/20 1.0000 1.0000 50 4

0.00%

0.00%

1.0000 0.00%

1.0000 1.0000 20/20 1.0000 1.0000 100 4

0.00%

0.00%

1.0000 0.00%

1.0000 CETIS' v1.9.7.7 007-238-492-3 QA:________

Analyst:________

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APPENDIX B REFERENCE TOXICANT DATA SHEETS Energy NW B5656.pdf Page 19 of 24

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APPENDIX C CHAIN OF CUSTODY Energy NW B5656.pdf Page 22 of 24

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