B09_CHOH_245002_287711_Amd_6_-_WQC-DC-2022-98_0006.pdf

April 3, 2023

Maryland Section Southern

Department of the Army

Baltimore District, U.S. Army Corps of Engineers

P.O. Box 1715

Baltimore, MD 21203-1715

Attn: Erica Schmidt

Mr. Scott Miller

Sorba Engineering

11710 Plaza America Drive

Suite 2000

Reston, VA 20190

Project: Water Quality Certification # DC-2022-98

Dear Ms. Schmidt and Mr. Miller:

The Regulatory Review Division (RRD) of the Department of Energy and Environment (DOEE) has evaluated the water quality certification application documents submitted by Sorba

Engineering on behalf of the National Park Service, Chesapeake and Ohio Canal Park (NPS or

“the Permittee”) on December 15, 2022 to DOEE RRD.

The Permittee proposes to rehabilitate sections of the C&O Canal locks and walls in

Georgetown, Washington, DC. Rehabilitation will include excavation for structural upgrades and sediment removal. The project will result in temporary impacts to the C&O Canal associated with a construction access road.

Please note that permits and authorizations from the U.S. National Park Service may also be required for the proposed activity. Contact the Right-of-Way Program Coordinator at (202) 619-

7276 for more information.

DOEE RRD hereby certifies that the proposed activity will comply with the District’s water quality requirements, including the Water Pollution Control Act of 1984, D.C. Official Code § 8-

103.01 et seq.; Water Quality Standards, 21 DCMR, Chapter 11; Water Quality

Monitoring Regulations, 21 DCMR, Chapter 19; and Critical Areas - General Rules and Critical

Areas - Wetlands and Streams, 21 DCMR, Chapters 25 and 26, provided the conditions listed below are incorporated into the permit and followed.

The Water Quality Certification # DC-2022-98 is issued to the Permittee for the activities described in the water quality certification request and application documents submitted to

DOEE RRD, subject to the following additional conditions:

1. The Permittee shall incorporate best management practices as an integral part of the performance of the work to ensure the activity will meet the Water Quality Standards of the District of Columbia and have minimal impact to the waters of the District of

Columbia.

2. Any water impacted by the project shall be pumped to an appropriate treatment system in order to comply with the Water Pollution Control Act of 1984, D.C. Official Code § 8-

103.02 and 21 DCMR § 1104.

3. Any oil sheen or other visible evidence of hydrocarbons or other pollution generated

(e.g., color changes in the water column, turbidity plumes) during any of the activities shall be immediately reported to DOEE Illicit Discharge and NPDES Branch at (202)

805-1355 and contained (e.g., oil boom, sorbent materials) or containerized in a sealed container in accordance with D.C. Official Code § 8-103.08.

4. All excavated (e.g., dredged) sediments and sampling sediments (e.g., within cofferdams or excess sediment samples), drill cuttings, drilling mud, and wastes (both solid and liquid) shall be contained, sampled, and analyzed for disposal at appropriate disposal sites. The wastes shall not be used as backfill material in the water body or on land in order to comply with the Water Pollution Control Act of 1984, D.C. Official Code § 8-

103.02 and 21 DCMR § 1104.

5. All debris and waste water must be captured and not enter the Canal and shall be contained and disposed of properly at an appropriate treatment facility to prevent materials from entering the water body in order to comply with the Water Pollution

Control Act of 1984, D.C. Official Code § 8-103.02 and 21 DCMR § 1104.

6. If groundwater is encountered and dewatering is necessary, the Permittee shall either request a Groundwater Discharge Permit from DC Water or submit a water quality monitoring, treatment and discharge plan to DOEE RRD for review and approval prior to dewatering.

7. To control turbidity, sediments, and work materials (e.g., concrete, sand, lumber) that will pass through the limits-of-disturbance (LOD) in surface water:

a. Weighted turbidity curtains must be used if sediments are being disturbed or if the Permittee uses anchored equipment such as boats or barges.

b. Weighted turbidity curtains must be used in all activity/work areas and around equipment and coffer dams. To minimize sediments from escaping the work area, adequate space must be provided between the work area and the turbidity curtains. Turbidity curtains must be kept closed during all work activity.

c. The turbidity curtains must be in place after the equipment is brought into the work area, but before the equipment is anchored (i.e., before setting anchors) and before sediment disturbing activities begin. This is necessary to prevent sediments, contaminants, and work materials (e.g., concrete, sand, lumber) from escaping the work area and being reintroduced into the water column during the work activity.

d. The turbidity curtains must be properly anchored, must touch the bottom except in a deep, tidally influenced stream channel (under such conditions, placement of the turbidity curtain must be based on manufacturer’s specifications), and encompass the entire area of activity, including coffer dams, barge, boat, and limits-of-disturbance, plus any equipment in the water. Where possible, the turbidity curtains must be able to withstand normal tidal or stream flow fluctuations.

8. To monitor turbidity in the LOD, the Permittee shall:

a. Establish background turbidity and measure turbidity by using U.S.

Environmental Protection Agency (EPA) approved methods in accordance with procedures outlined in 40 C.F.R. Part 136. Background turbidity must be established before starting any work, before equipment is anchored, and before any turbidity curtains or coffer dams are in place. These measurements must be made within 25 feet upstream and 25 feet downstream outside of the curtains.

Measurements must be conducted at different depths, for example, near the bottom, ¼ of the depth from the bottom, ¾ of the depth from the bottom, and near the surface.

b. Once the operations begin, turbidity measurements must be taken continually from the same locations within 25 feet upstream and 25 feet downstream of the turbidity curtains. This is to ensure compliance with District of Columbia

Water Quality Standards in 21 DCMR § 1104.8. Turbidity monitoring must be conducted at different depths, for example, near the bottom, ¼ of the depth from the bottom, ¾ of the depth from the bottom, and near the surface. If turbidity measurements exceed a maximum of 20 Nephelometric Turbidity Units (NTU) above background turbidity, stop all activities and implement best management practices until the 20 NTU maximum differential (i.e., background turbidity + 20

NTU) is reached.

c. If a sediment plume is observed coming out of the sediment-disturbing activity location or if the turbidity exceeds the District of Columbia surface water quality standard, the Permittee shall:

i. Immediately stop all activities and notify DOEE Illicit Discharge and

NPDES Branch at (202) 805-1355; and

ii. Adjust all activities and implement best management practices until there is no more sediment escaping the sediment-disturbing activity location. When the measured turbidity is less than or equal to the background turbidity, the Permittee may resume the work.

d. Prior to opening turbidity curtains, turbidity measurements must be taken inside the turbidity curtains. The turbidity curtains must not be opened until the levels inside the turbidity curtains are below the 20 NTU maximum differential. This is to ensure compliance with District of Columbia Water Quality Standards in 21

DCMR § 1104.8.

e. The turbidity readings must be recorded in a logbook and kept on site. In addition to the turbidity readings, records must also be kept of the date and time of the readings, and name(s) of the person(s) taking the sample and making the readings.

9. Given known historic contamination within the project area, the following conditions will apply:

a. All excavated (e.g., dredged) sediments and sampling sediments (e.g., within cofferdams or excess sediment samples), drill cuttings, drilling mud, and wastes

(both solid and liquid) shall be contained, sampled, and analyzed for disposal at appropriate disposal sites. The wastes shall not be used as backfill material in the water body or on land in order to comply with the Water Pollution Control

Act of 1984, D.C. Official Code § 8-103.02 and 21 DCMR § 1104.

b. If excavation/sediment removal activities encounter water or groundwater within the LOD that is otherwise within the “dry” dam-and-pump-around area, water column samples must be collected and analyzed before dewatering the area.

Sampling shall be conducted according to the following water quality sampling requirements to monitor and determine if the project will violate any water quality standards in the District of Columbia:

i.All water samples must be collected and analyzed for the following parameters in accordance with EPA approved methods in accordance with

40 CFR 136:

Analytical Parameter Method

VOCs 624.1

SVOCs 625.1

PAHs 610

Pesticides/PCBs 608.3

TPH-DRO 8015M

TPH-GRO 8015M

Total Metals 200.8

Dissolved Metals 200.8

Hardness and pH 130.1

ii. Sample results and a report must be submitted to DOEE for review.

iii. If sample results reveal that the water is contaminated, then a dewatering and treatment plan must be submitted to DOEE for review and approval prior to the use of any sump pumps and before dewatering commences.

10. The Permittee shall obtain all necessary permits and other authorizations from appropriate federal and local offices, including permits for Stormwater Management and

Erosion and Sediment Control from DOEE in accordance with 21 DCMR §§ 516-534 and

540-547. All staging and temporary activity areas not covered by any permit shall have adequate soil erosion and sedimentation measures.

11. In the District, the anadromous fish migration and spawning season is generally considered to occur between March 1st and June 30th. Any activities proposed to occur in District waters during this period shall first be approved by the U.S. Army Corps of

Engineers, accompanied by concurrence from commenting federal agencies, including the U.S. National Park Service, U.S. Fish and Wildlife Service, and U.S. National

Oceanic and Atmospheric Administration. All of the aforementioned approvals must be submitted to and subsequently certified by DOEE Fisheries and Wildlife Division (FWD) in accordance with 21 DCMR § 1405 to ensure compliance with 21 DCMR §§ 1101 and

1104. Please contact DOEE FWD at rese.cloyd@dc.gov to request a time of year restriction waiver.

12. The Permittee shall obtain all required permits and authorizations from the U.S. National

Park Service. Please contact the Right-of-Way Program Coordinator at

Hannah_Dean@nps.gov or (202) 619-7276 for more information.

13. Temporary impacts to the C&O Canal must be mitigated in-place by restoring those resources to pre-construction condition or better.

14. Reporting Requirements:

a. The Permittee shall submit written notification to DOEE RRD at least seven (7) business days before work commences in accordance with 21 DCMR § 2502.3.

b. If the Permittee observes any water quality standard exceedances at the site, the

Permittee must notify DOEE Illicit Discharge and NPDES Branch immediately at

(202) 805-1355, stop the work, prepare and submit for review and approval a corrective action plan, and then implement the DOEE-approved corrective action plan in accordance with D.C. Official Code § 8-103.08.

c. Through the duration of permitted activities, the permittee shall submit weekly turbidity monitoring reports to DOEE RRD through SGS by the close of business every Tuesday after the one week reporting period. Reports should contain the data recorded in the logbook kept onsite, including:

i. the date and time of each turbidity reading,

ii. the daily background turbidity readings, mailto:rese.cloyd@dc.gov mailto:Hannah_Dean@nps.gov

iii. the calculated differential of each reading compared to the daily background reading,

a. If any readings exceeded 20 Nephelometric Turbidity

Units (NTU) above background turbidity, provide details on how activities were stopped, confirmation that DOEE Illicit

Discharge and NPDES Branch was notified, and details on best management practices that were implemented until the 20 NTU maximum differential was reached.

iv. name(s) of the person(s) taking the sample and recording the readings,

v. location and distance of each measurement relative to the turbidity curtain or cofferdam/dewatering equipment,

vi. depth of each reading,

vii. notes, and

viii. photos (as applicable).

d. The Permittee shall submit final reports of the monitoring results. Reports must be submitted to DOEE RRD no later than 45 days after the completion of the work. All data generated during the operation shall be summarized in a final report. The report shall also include any violations, water quality standards exceedances, actions taken or to be taken to remediate those violations, and any other relevant information. The report shall be submitted to wetlandprogram@dc.gov

This certification expires when the permit issued by the U.S. Army Corps of Engineers expires. Failure to comply with these conditions shall constitute reasons for cancellation of this certification. Legal proceedings may be instituted against the Permittee in accordance with

District of Columbia and federal laws and regulations to control water pollution in the

District. DOEE reserves the right to conduct inspections at any time during the construction process to determine if an activity complies with the terms and conditions authorized in this certification and the permit.

Please direct your questions or comments on this water quality certification to Jennifer Dietzen, Regulatory Review Division, at (202) 481-3942 or jennifer.dietzen@dc.gov.

Sincerely, Nicholas Bonard on 4/3/2023 for

Meredith Upchurch

Associate Director, Regulatory Division mailto:wetlandprogram@dc.gov