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HomeMy WebLinkAbout12. Approve Outfall Improvements, Phase 7, DP 7353, for CEQA and regulatory permitting purposes Page 1 of 3 Item 12. CENTRAL SAN BOARD OF DIRECTORS vie . , Hill. , , . . POSITION PAPER MEETING DATE: NOVEMBER 7, 2019 SUBJECT: APPROVE THE OUTFALL IMPROVEMENTS, PHASE 7, DISTRICT PROJECT 7353, FOR CALIFORNIA ENVIRONMENTAL QUALITYACT (CEQA)AND REGULATORY PERMITTING PURPOSES SUBMITTED BY: INITIATING DEPARTMENT: RITA CHENG AND MARK WENSLAWSKI, ENGINEERING AND TECHNICAL SERVICES- ASSOCIATE ENGINEERS ERC-REGULATORY COMPLIANCE RUSS LEAVITT, ENGINEERING ASSISTANT III REVIEWED BY: DANEA GEMMELL, PLANNING AND DEVELOPMENT SERVICES DIVISION MANAGER EDGAR J. LOPEZ, CAPITAL PROJECTS DIVISION MANAGER LORI SCHECTEL, ENVIRONMENTAL AND REGULATORY COMPLIANCE DIVISION MANAGER JEAN-MARC PETIT, DIRECTOR OF ENGINEERINGAND TECHNICAL SERVICES Roger S. Bailey General Manager ISSUE Board approval of the Outfall Improvements, Phase 7, District Project 7353, is required prior to the filing of a Notice of Exemption under the California Environmental Quality Act (CEQA) Guidelines. BACKGROUND The National Pollutant Discharge Elimination System (NPDES) Permit CA0037648, Order No. R2-2017- 0009 (Permit) requires Central Contra Costa Sanitary District (Central San)to properly operate and maintain its 3.5 mile, 72-inch reinforced concrete outfall pipeline. Every five to ten years, Central San drains and inspects the outfall pipeline, verifies the alignment and assesses the physical integrity of the November 7, 2019 Regular Board Meeting Agenda Packet- Page 96 of 414 Page 2 of 3 pipe joint seals, and makes any necessary repairs. Central San's NPDES Permit, Attachment F, Section I I.B states that Central San plans to conduct an outfall inspection and necessary repairs during the current permit cycle ending in May 2022. During the outfall inspection and repairs, treated effluent is diverted to a holding basin for discharge to Lower Walnut Creek via the overflow weir structure at the treatment plant in accordance with permit requirements. During normal operation, Central San discharges treated wastewater effluent to Suisun Bay through the 72-inch outfall pipeline. Constructed in 1958, the outfall pipeline runs primarily underground for nearly 19,000 feet and the submarine section of the outfall is about 1,700 feet in length. Above the underground pipeline, an unvegetated, tidal mudflat extends approximately 1,000 feet from the shoreline edge into the Suisun Bay. The end of the submarine section of the outfall consists of 11 diffusers and three manhole access structures that rise above the water surface, which are used to identify the location of the submerged manholes and provide a working maintenance platform. As part of the 2012 Outfall Improvements, Phase 6 Project, the outfall was dewatered, inspected, repaired, and surveyed. Additionally, over 1,500 pipe joint seals were inspected, 368 joints were repaired with new seals, and ballast rocks were deployed in Suisun Bay to stabilize the submarine portion of the pipeline. Of the total 1,500 joints, approximately 950 joints have been repaired since the construction of the pipeline. In 2017, Central San hired divers to perform an external inspection of the submarine diffuser lines and wooden manhole access structures straddling the outfall pipeline. The 11 diffusers and the piles were all found to be in good working conditions; however, some of the braces, platforms, and ladders on the manhole access structures are missing or in need of repair to ensure structural integrity. In July 2019, corrosion consultants conducted a condition assessment on the manhole risers of the land portion of the outfall and found moderate corrosion on many of the risers. Installation of galvanic anodes and test stations, as well as a new anti-corrosive coating system on the manhole risers, was recommended by the consultants to ensure the structural integrity of the manhole risers and prevent outfall leakages. This project will allow for the inspection of the land portion of the outfall, and to make any repairs that are identified during the inspection. The project will retest the joints of the land portion of the outfall in a similar fashion to the work performed in 2012, and install new joint seals, as necessary. Repairs on the three wooden trestle structures over the submarine portion of the outfall will be performed via boat in Suisun Bay. Galvanic anodes and test stations will be installed at each of the 23 manhole risers on the land portion for corrosion control. The pipeline will be surveyed to monitor the outfall alignment. Since the outfall will be out of service, this project will also replace two 60-inch valves, install two standby effluent valves, perform Structure D concrete repairs, install a new 30-inch flowmeter at the 9000 Valve Structure, and perform seismic improvements to the 9000 Valve Structure. Staff will coordinate with and obtain necessary approval and/or permits from the San Francisco Bay Regional Water Quality Control Board, United States Army Corps of Engineers, San Francisco Bay Conservation and Development Commission, California Department of Fish and Wildlife, and any other applicable agencies. Some of these permits will require proof of CEQA determination. CEQA Staff has concluded that this project is exempt from CEQA under CEQA Guidelines in the California Code of Regulations Section 15301, since it involves repairs to an existing sewage facility with no increase in capacity. Approval of this project will establish the Board of Directors' independent finding that this project is exempt from CEQA. ALTERNATIVES/CONSIDERATIONS Alternatives to this project, such as deferment or reduction of project scope, are not recommended by November 7, 2019 Regular Board Meeting Agenda Packet- Page 97 of 414 Page 3 of 3 staff because proper maintenance of the outfall pipeline is required by the NPDES permit and the outfall pipeline is critical to operations.A reduced scope would pose high operational and regulatory risks, which could lead to more costly repairs in the future. FINANCIAL IMPACTS The total estimated cost for the project is $5,500,000; however, this position paper only approves the project for CEQA and permitting purposes and does not award a construction contract. The Outfall Improvements, Phase 7, District Project 7353 is included in the Fiscal Year(FY) 2019-20 Capital Improvement Budget on page 186 of the FY 2019-20 Budget. COMMITTEE RECOMMENDATION The Engineering and Operations Committee has reviewed this subject at its meeting on October 29, 2019 and recommended approving the Outfall Improvements, Phase 7, District Project 7353 for CEQA and permitting purposes. RECOMMENDED BOARD ACTION Approve the Outfall Improvements, Phase 7, District Project 7353 for CEQA and permitting purposes and direct staff to file a Notice of Exemption. Strategic Plan Tie-In GOAL TWO: Strive to Meet Regulatory Requirements Strategy 1 - Strive to achieve 100%permit compliance in air, water, land, and other regulations, Strategy 2- Strive to minimize the number of sanitary sewer overflows, Strategy 3- Comply with all federal, state, and local regulations related to District administration GOAL FIVE:Maintain a Reliable Infrastructure Strategy 1 - Manage assets optimally throughout their lifecycle, Strategy 2- Facilitate long-term capital renewal and replacement, Strategy 3- Protect District personnel and assets from threats and emergencies November 7, 2019 Regular Board Meeting Agenda Packet- Page 98 of 414