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Home My WebLink About06. Authorize the General Manager to execute a professional engineering agreement with Carollo Engineers, Inc., in an amount not to exceed $300,000 for design of Sewer Mains to facilitate abandonment of Main Trunk No.1 as part of District Project 100007Page 1 of 8 Item 6. DCENTRALSAN MEETING DATE: NOVEMBER 2, 2023 BOARD OF DIRECTORS POSITION PAPER SUBJECT: AUTHORIZE THE GENERAL MANAGER TO EXECUTE A PROFESSIONAL ENGINEERING AGREEMENT WITH CAROLLO ENGINEERS, INC., IN AN AMOUNT NOT TO EXCEED $300,000 FOR DESIGN OF SEWER MAINS TO FACILITATE ABANDONMENT OF MAIN TRUNK NO. 1 AS PART OF THE LARGE DIAMETER SEWER RENOVATIONS, DISTRICT PROJECT 100007; AND FIND THE PROJECT IS EXEMPT FROM THE CALIFORNIA ENVIRONMENTAL QUALITYACT (CEQA) SUBMITTED BY: INITIATING DEPARTMENT: DANA LAWSON, SENIOR ENGINEER ENG-PDS-DIVISION MANAGER REVIEWED BY: DANEA GEMMELL, PLANNING AND DEVELOPMENT SERVICES DIVISION MANAGER GREG NORBY, DEPUTY GENERAL MANAGER - OPERATIONS Roger S. Bailey Leah Castella General Manager District Counsel ISSUE The Board of Directors (Board) authorization is required for the General Manager to execute professional engineering agreements in an amount greater than $200,000. BACKGROUND Central San owns 76 miles of wastewater trunks and interceptors ranging from 24-inches to 102-inches in diameter. The typical lifespan of large sewers ranges from 50 to 150 years depending on pipe material, hydraulic, operating, and environmental conditions. Nearly half of Central San's large sewers are over 50 years old, including Main Trunk No. 1 (39-inch diameter), which is approximately 73 years old and has November 2, 2023 Special Board Meeting Agenda Packet - Page 25 of 79 Page 2 of 8 reached the end of its useful life. This phase of the project will re-route the remaining flow at the most downstream end of Main Trunk No. 1, which was installed in 1950 to bring sewage to the wastewater treatment plant when it was first constructed. The pipeline is located within an easement that was originally granted by Bay Cities Dirt Track Speedway. In the mid 1960s, three mobile home parks were constructed over Main Trunk No. 1, with numerous mobile homes encroaching into the easement, which significantly impacts Central San's ability to replace the pipe within the easement. Therefore abandonment is beneficial to the mobile home parks to eliminate the encroachment concern and the easement can be quitclaimed to return land rights to the three parcels. Main Trunk No. 1 is currently exposed across Grayson Creek due to erosion activities over the last 70 years, so the span across the creek is no longer structurally sound. Therefore removal of this 39-inch pipe is environmentally beneficial since it reduces the possibility of a sewage event into waters of the State. Additionally, the routine desilting maintenance activities of the Flood Control District are limited with this pipe crossing, so removal provides a public benefit by, potentially, allowing improvements to the channel's capacity. As central Contra Costa County was developed, two additional interceptors, the A -Line (90-inch diameter) and A -Line Relief Interceptor (102-inch diameter), were constructed in the early 60s and 90s, respectively; therefore Main Trunk No. 1 is not needed for influent capacity since the two interceptors provide sufficient hydraulic capacity to accommodate peak dry weather flows (PDW F) and average wet weather flows (AWWF), which been re -verified with the updated hydraulic model in 2023. During their construction, junction structures were installed to divert flow from Main Trunk No. 1 near, current -day, Target and Buchanan Golf Course, and which will be the upstream limit for abandonment of Main Trunk No. 1. However, Main Trunk No. 1 was not abandoned at that time since staff were aware of the Contra Costa Transportation Authority's interchange improvement project and anticipated needing Main Trunk No. 1 for bypassing when the 84-inch portion of the A -Line along Berry would have to be relocated. As the final phase of the interchange improvement project is imminent, preparations to abandon Main Trunk No. 1 may now proceed. I n summary, this phase of DP 100007 will install approximately 3300 LF of 8-inch main sewers to re-route flow from 5 points -of -connection on Main Trunk No. 1 to the A -Line Relief Interceptor in Marsh Drive and 3 points -of -connection to the 78-inch portion of the A -Line in Berry Drive and south of Center Avenue to the Golf Course. After the new sewer mains are in-service and the 84-inch portion of the A -Line has been relocated (as Main Trunk No. 1 is needed for bypassing during relocation prior to the interchange improvements), then approximately 6600 LF of the Main Trunk No. 1 can be abandoned -in -place by filling with controlled low strength material (CLSM) while the stretch across Grayson Creek will be removed (unless otherwise directed by the California Department of Fish and Wildlife who has jurisdiction in that location). California Environmental Quality Act (CEQA) Staff has concluded that this project is exempt from California Environmental Quality Act (CEQA) under District CEQA Guidelines Section 15302 (Replacement or Reconstruction), since the new structure will be located on substantially the same site as the structure replaced and will have substantially the same purpose and will not increase influent capacity. Approval of this project will establish the Board's independent finding that this project is exempt form CEQA. ALTERNATIVES/CONSIDERATIONS The Board may decline authorization of the agreement. This is not recommended as the agreement provides design services to facilitate an asset that has reached the end of its useful life. November 2, 2023 Special Board Meeting Agenda Packet - Page 26 of 79 Page 3 of 8 FINANCIAL IMPACTS The design cost including Central San staff time for project management, right-of-way and survey is $400,000, this current fiscal year (FY). The planning -level total cost estimate is $3,400,000, which includes planning, design, and construction for this phase of the program. This project is a phase of the Large Diameter Sewer Renovations, DP 100007, included in the FY 2023- 24 Capital I mprovement Budget (Cl B) on page 223 with a total estimated program budget of $11,000,000. There are sufficient funds in the sewer construction fund and this District Project for this phase of the program. COMMITTEE RECOMMENDATION The Engineering and Operations Committee reviewed this matter at the October 23, 2023 Committee Meeting and recommended approval. RECOMMENDED BOARD ACTION Staff recommends the Board authorize the General Manager to execute the agreement with Carollo Engineers, Inc. in an amount not to exceed $300,000; and find the project is exempt from the California Environmental Quality Act (CEQA). Strategic Plan re -In GOAL ONE: Customer and Community Strategy 3 - Build neighborhood and industry relations GOAL SIX: Infrastructure Reliability Strategy 1 - Manage assets optimally, Strategy 2 - Execute long-term capital renewal and replacement program ATTACHMENTS: 1. Map 2. Presentation November 2, 2023 Special Board Meeting Agenda Packet - Page 27 of 79 1d 1 a, �,1:, .. { 1 s t k k a � r X�y. S 4Sr�r9 } on ilp A- ,o, a fl S - q } 2 Flue .'.I � r • ,ES k hr„a5p�' 131 H.ni �d� tiay-. '_�nG - Muir r .i 6,aYd"v4 ay i ✓, n¢ P oil 4 � T • Notes F�= Central San Map ° C'� -' = bru a, Large Diameter Sewer Renovations, DP 100007 (Phase 1) ' ntti J -- • Fr � 33 vi � F r:N" '-__#_- urrunrri Yin e }p a ON 0 4 9$Y v 4• 1`Lr3.a„I Dr % d� yt# "A L* stn il Buchanan t Field North Lift Station Buchanan Field South _ Lift Station 'r L 5A PJ` • G f f� ab 1,� ..' 4 This map is a user generated static output from Central San's ,e'4o�ICENTRAL SAN j Geoportal and is for reference only. Data layers that appear on this 0 800 1,600 Feet r—jk map may or may not be accurate, current, or otherwise reliable. N Map Created On:9/26/2023 Map Projection: WGS84 Attachment 1 Page 5 of 8 1 Overview Abandon 6600 LF of 39" trunk sewer by installing 3300 LF of 8" main sewers In 1950, the first trunk sewer, Main Trunk No. 1, was installed to bring flow from central county to the newly constructed (primary) treatment plant Main Trunk No. 1 has reached the end of its useful life This project will install sewer mains to re- route flow from 8 points -of -connection to Main Trunk No. 1 to the A -Line and A -Line Relief Interceptors 2 Relocation , for CCTA (DP 100050 r77--; ATTACHMENT 2 =� k � x x � k k ,J. Reach Nc. I November 2, 2023 Special Board Meeting Agenda Packet - Page 29 of 79 1 Page 6 of 8 Scope of Work - Reach 1 Install —2800 LF of 8" main sewers within easements and ' J private roads of 3 mobile home parks �� _� i Diverts 5 sewersheds east into the 102" A -Line Relief Interceptor in Marsh Drive, connecting at new trunk manholes Allows abandonment of —4400 LF of 39" pipe Public outreach and Right -of -Way at mobile home parks and commercial parcel will be handled by Central San Note: Per Central San Standard Specs, sewers within mobile - home parks should be private since it serves one parcel; and — Q would allow full quitclaims. �8 3 Scope of Work - Reach 2 Renovate and extend 3 sewer mains (-527 LF) west into the 78" A -Line in Berry Drive, connecting at new trunk manholes Approx. 6 laterals will need to be reconnected Allows abandonment of —2200 LF of 39" pipe Upstream connection at Junction Structure 24 near Golf Course will require modification to plug connection to 39" prior to abandoning in place by filling with controlled low strength material (CLSM) 4 I J November 2, 2023 Special Board Meeting Agenda Packet - Page 30 of 79 2 Page 7 of 8 Summary: Abandon 6600 LF 39" by installing 3300 LF 8" Reach I — Mobile Home Parks Reach 2 — Berry Drive New POCs LF Std MH Trk MH New POCs LF Trk MH j 1 706 3 1 6 300 1 2 698 2 1 7 202 1 8 25 (10") 1 4 466 3 1 S 270 1 1 Subtotal 502 8" 3 `1; r Subtotal 2791 12 5 25 10" Abandon LF Abandon LF JSI-M9 630 M6-M30 663 M9-M 10 433 M30-M34 436 t°gl,^,'•;7 x•;'` M10-MII MII-M3 745 775 M34-M36 142 _r v� M3-M4 572 M36-M37 938 A� M4-MS MS-M6 572 467"� M37-J524 25 � ; Subtotal 4397 Subtotal 2204 5 Coordination of Projects Location Bypassing Permitting • Same area and • Abandonment of 39" Removal of 39" serving same cannot occur until across Grayson sewershed for DP after the A -Line is Creek may be I00050,A-Line relocated since it is combined with Relocation for CCTA, needed for bypassing permitting and DP 100007, Large discussions for A -Line Diameter Renovation Relocation (Flood Control (39" abandonment) District and CA Dept of Fish & Wildlife requirements) I November 2, 2023 Special Board Meeting Agenda Packet - Page 31 of 79 3 Page 8 of 8 Project Schedules DP 100050,7 7-- A-LineDesign Bid nsuruct� Relocation for CCTA DP 100007, Large D _ (N — sr) (Spring �JC(sunnr�;,' X (use 39" for bypassine.)#]W Diameter Renovation 1 Program *Bid and Construction ofA-Line relocation pending CCTA authorization and funding November 2, 2023 Special Board Meeting Agenda Packet - Page 32 of 79 4