rfb_13242_info_only_water_sewer_separation_waiver.pdf

State Water Resources Control Board Division of Drinking Water

Sent via email: jose.martinez@otaywater.gov

May 15, 2025

Jose Martinez General Manager 2554 Sweetwater Springs Blvd.

Spring Valley, CA 91978

OTAY WATER DISTRICT, SYSTEM NO. 3710034

POTABLE WATER SEPARATION FOR “JAMACHA FORCE MAIN AND GRAVITY

MAIN SEWER IMPROVEMENTS”

Dear Mr. Martinez:

On April 9, 2025, the State Water Resources Control Board, Division of Drinking Water (Division), received a revised water main separation waiver application and design plans for the “Jamacha Force Main and Gravity Main Sewer Improvements” project for Otay Water District (OWD). The relevant plan sheets, waiver request checklist, and OWD’s letter of concurrence are attached for reference.

The project is in the La Presa neighborhood of the City of San Diego and includes installation of new forced sewer mains. OWD has identified one location where the piping does not conform to section 64572, title 22 of the California Code of Regulations.

At one location, the proposed dual 18-inch high-density polyethylene (HDPE) forced sewer mains will parallel an existing 10-inch asbestos cement (AC) potable water main for 33 linear feet. The minimum horizontal separation at this location will be 4.8 feet measured from the outer diameter to outer diameter (OD to OD) of each pipe. The water main will be at least 10.8 feet vertically higher than the forced sewer mains, measured from OD to OD. Minimum horizontal separation standards cannot be met due to congestion of existing utilities and roadway space restrictions. The proposed dual forced sewer mains will be constructed of upgraded material, DR-11 HDPE, with fused joints. The forced sewer mains will have an operating pressure of 60 psi. The existing water mains are constructed of class 150 AC pipe, with push on joints. The water mains have an operating pressure of 140 psi.

mailto:jose.martinez@otaywater.gov

Otay Water District Jose Martinez May 15, 2025 Water System No. 3710034

The dual 18-inch forced sewer mains will cross below the existing 10-inch water main with a minimum crossing angle of 45 degrees. At the crossing the water main will be at least 10.8 feet vertically higher than the forced sewer mains.

The Division concurs with the water utility’s determination that the proposed design provides at least the same level of protection to public health as the separation criteria in section 64572. The Division hereby approves the submitted plans in accordance with section 64551.100 Waivers and Alternatives.

We appreciate the opportunity to comment on the plans and look forward to working with you on future projects. If you have any questions regarding this letter, please contact Trevor Gresham or me at (619) 525-4159.

Sincerely, Joseph Guzman, P.E.

District Engineer

Enclosures:

(1) Pipeline separation checklist

(2) Sheets 6 and 11 of the design plans for the “Jamacha Force Main and

Gravity Main Sewer Improvements” project

(3) OWD letter of concurrence cc: Heather Buonomo, REHS, Director of Environmental Health, County of San Diego, Department of Environmental Health and Quality (via email)

Joanne Lee, MPH, REHS, Department Operations Chief, Land and Water Quality Division, County of San Diego, Department of Environmental Health and Quality (via email)

David Blalock, Senior Civil Engineer, Otay Water District (via email)

Black & Veatch Corporation 300 Rancheros Dr., Suite 250, San Marcos, CA 92069

P +1 760-621-8533 E EvansR@BV.com

February 7, 2025

William DeBiase State Water Resources Control Board Division of Drinking Water

Subject: Potable Water Pipe Separation for County of San Diego’s Proposed “Jamacha Force Main and Gravity Main Sewer Improvements (La Presa Project I)” Project with Otay Water District’s 10-inch Asbestos Concrete Pipeline

Dear Mr. DeBiase:

County of San Diego is currently working towards construction of dual 18-inch sewer force mains to replace the existing 12-inch sewer force main on Jamacha Boulevard, in Spring Valley, California. As shown on the attached exhibit (a copy of Sheet 11 from the Issued for Bid Plans), a portion of the proposed force mains (located between La Presa Street and Pecos Street) from STA 75+ 80.31 to STA 76+12.00 (approximately 32 linear feet), 10-feet standard horizontal separation between the existing 10-inch water main and the proposed 18-inch sewer force mains is not achievable due to utility congestion and restricted roadway space. The closest horizontal separation at this location between the outside edges of the pipelines is 4.8 feet. However, the proposed sewer force mains will be installed more than 10 feet deeper than the existing 10-inch water main.

The proposed force mains are HDPE DR 11 pressure pipe with fused joints, which will protect the existing 10-inch water main by minimizing the potential for contamination.

Please see attached documents showing the proposed force main design (plan and profile views) and the Pipeline Separation Checklist.

We look forward to a reply with your concurrence with the proposed design.

Thank you, Water System Name: WS Number:

Name of Applicant:

Contact Phone: Email:

Project Name: Location:

The Waterworks Standards in the California Code of Regulations (CCR) Title 22, Chapter 16, Section 64572 provide separation criteria for new construction. When buried water mains are in close proximity to non-potable pipelines, the water mains are vulnerable to contamination that can pose a risk of waterborne disease outbreaks.

Per CCR Title 22, Chapter 16, Section 64551.100, a water system that proposes to use an alternative to a requirement in Chapter 16 shall: 1) demonstrate to the State Board that the proposed alternative would provide at least the same level of protection to public health; and 2) obtain written approval from the State Board prior to implementation of the alternative. Requests for alternatives to the Waterworks Standards must consist of information requested in the Pipeline Construction Information tab. The information must be submitted to the Division of Drinking Water District Office for review and approval prior to construction.

Please Note: The information may be submitted using this checklist or another format, but all relevant information must be provided to the Division of Drinking Water District Office for consideration.

STATE WATER RESOURCES CONTROL BOARD

Waterworks Standards Main Separation Alternative - Request Checklist Division of Drinking Water

760-621-8533

Otay Water District

Black & Veatch

Jamacha Force Main and Gravity Main Sewer Improvements

Jamacha Blvd. between La Presa St. and Pecos St.

evansr@bv.com

Attach detailed plans with vertical profile and horizontal alignment, specifications, and other exhibits necessary to show the standard installation and the proposed installation for which the alternative is being requested.

No.

Plan

Sheet Station Range

Utility Type

Nom.

Size (in)

Operating Pressure

Pipe Material

AWWA

Material

Designation

Pressure Class/

Thickness

Joint Type

Utility Type

Nom.

Size (in)

Operating Pressure

Pipe Material

AWWA

Material

Designation

Pressure Class/

Thickness Joint Type

Age/ Condition

Crossing or parallel?

Length of parallel section (ft)

Angle (if crossing)

Which utility is higher?

Vertical (ft)

Horizontal (ft)

Explanation of why the new pipeline cannot be installed in accordance with Waterworks

Standards

Proposed Protective Measures (material construction methods, operational considerations, etc.)

DDW Comments

1 6 26+03.79 to

26+36.00 SWR 18 60 psi HDPE

ASTM

F714 equivalent to AWWA

C906

DR-11 Fused WTR 10 140 psi Asbestos Concrete

Pipe C400 CI 150 Push On

Installed in 1958

Parallel 33 - WTR 10.8 7.3 congested utilities in restricted roadway space; existing force main to remain in service during a portion of construction (replacement in its current location not feasible)

Proposed Protective Measures include upgraded material for the proposed sewer mains (Fused HDPE pipe). DR11 (rated for 160 psi) selection is conservative relative to the operating pressure

(Safety Factor ~2.5) and the modeled surge pressure (max pressure of ~110 psi - only anticipated upon power failure at the pump station - Safety Factor ~1.5). HDPE piping also provide additional surge allowance beyond the rated pressure

(additional 80 to 160 psi beyond the pressure class = up to 320 psi). Fused pipe is best suited for handling negative and extreme pressures within the pipeline that may be caused by potential surge events. Fused

HDPE piping provides the maximum level of protection against pipeline leakage/failure (significant upgrade vs. PVC or Ductile Iron Pipe with push on joints).

2 11 75+80.31 to

76+12.00 SWR 18 60 psi HDPE

ASTM

F714 equivalent to AWWA

C906

DR-11 Fused WTR 10 140 psi Asbestos Concrete

Pipe C400 CI 150 Push On

Installed in 1958

Parallel 32 - WTR 10.8 4.8 congested utilities in restricted roadway space; existing force main to remain in service during a portion of construction (replacement in its current location not feasible) upgraded material for the proposed sewer mains (HDPE with fused joints). See above for additional information.

Notes:

all distances are measured from outside walls of both pipelines Utility type: Domestics Water / Raw Water / Recycled Water / Sewer / Force Sewer / Storm Drain / Other (describe) Pipe Material: Ductile Iron / Cast Iron / Welded Steel / HDPE / PVC / Concrete / Vitrified Clay / Other (describe) Joint Type: Push On / Restrained / Welded / Fused / Other (describe)

Proposed Pipeline Existing Pipeline - Paralleling or Crossing the Proposed Pipeline Separation (OD-OD)Location

CERTIFYING SIGNATURE:

Attached concurrence?:

3/28/2025 Signature Date

Name and Title

For consultants, contractors, and developers: attach written concurrence from the governing water system and pipeline owners stating that the selected project alternative is the preferred alternative.

I certify that the forgoing information is true and correct to the best of my ability, and that I believe this alternative would provide at least the same level of protection to public health as the minimum separation distances prescribed in the California Waterworks Standards (CCR, Title 22, Section 64572).

Rika Evans, P.E. Engineering Manager, Black & Veatch

N/ANoYes

THE ANGLE BETWEEN THE NEW FORCE MAIN AND THE EXISTING

WATER MAIN SHALL BE 45 DEGREES MINIMUM. CONTRACTOR

SHALL FIELD VERIFY THAT THE MINIMUM ANGLE REQUIREMENT

IS ACHIEVED IN COORDINATION WITH OWD INSPECTION GROUP.

SEE OWD WATER NOTES ON SHEET 2.

The minimum angle of 45 degrees will be field verified (see Keynote 3)

THE ANGLE BETWEEN THE NEW FORCE MAIN AND THE EXISTING

WATER MAIN SHALL BE 45 DEGREES MINIMUM. CONTRACTOR

SHALL FIELD VERIFY THAT THE MINIMUM ANGLE REQUIREMENT

IS ACHIEVED IN COORDINATION WITH OWD INSPECTION GROUP.

SEE OWD WATER NOTES ON SHEET 2.

The minimum angle of 45 degrees will be field verified (see Keynote 3) https://otaywater365.sharepoint.com/sites/engoperating/Shared Documents/Engineering/P1287 Outside Agency Projects/SD County Sanitation District/Jamacha Force Main/Cor/OWD Concurrence to DDW-Jamacha Force Main-April 2025.docx

Dedicated to Community Service

2554 SWEETWATER SPRINGS BOULEVARD, SPRING VALLEY CA 91978-2096 - TELEPHONE (619) 670-2222

April 9, 2025

State Water Resources Control Board Division of Drinking Water District 14 – San Diego

Dear Sir/Madam:

The Otay Water District concurs with Black & Veatch’s design for the Jamacha Force Main and Gravity Main Improvement Project for the County of San Diego (W.A. 1022027).

Due to utility congestion within Jamacha Road, there is a 33-foot section where the construction of new dual 18-inch fused HDPE force mains does not fully comply with Section 64572, Title 22 of the California Code of Regulations. In this location, the proposed force mains will parallel the District’s existing 10-inch asbestos cement water main, with a horizontal separation ranging from 4.8 feet to 7.3 feet (outside diameter to outside diameter). However, the sewer force mains will be installed at least 10 feet below the existing water main.

The existing water main, constructed in 1957, is a Class 150 asbestos cement pipe with push-on joints and operates at approximately 140 psi. The proposed dual force mains will consist of fused DR-11 HDPE pipe, operating at 60 psi.

This fused pipe is considered an upgraded material and, once fused, forms a continuous pipe with no mechanical joints, thereby ensuring an 8-foot joint-free horizontal clearance is maintained and minimizes the potential for contamination.

Sincerely, David Blalock, P.E.

Senior Civil Engineer

(619) 670-2209 DBlalock@otaywater.gov

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Gresham, Trevor David Blalock RE: Otay Water District - Pipeline Separation Waiver Wednesday, May 21, 2025 12:44:22 PM

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David, The waiver is for the “Jamacha Force Main and Gravity Main Sewer Improvements” project. The location is clearly indicated on the checklist and design plans, which are included as attachments to the waiver and should not be confused for another location.

Sorry for the small error.

Best, Trevor Gresham

From: David Blalock Sent: Friday, May 16, 2025 7:57 AM To: Gresham, Trevor Subject: FW: Otay Water District - Pipeline Separation Waiver

Good morning Trevor, After review of the waiver a small error was found. The neighborhood of La Presa is located in the County of San Diego and not the City. Is it possible to get this revised and a new/revised waiver issued?