2020-002a NASSCO Facility Maintenance Amendment

2020-002a NASSCO Facility Maintenance Amendment

The proposed project (Project) would involve maintenance and repairs throughout the General Dynamics-NASSCO (Tenant) leasehold in the City of San Diego, California. The Project includes various activities that would facilitate and streamline the permitting requirements for each activity presented. A Coastal Act Categorical Determination of Exclusion (CatDet) (Project No. 2020-002) was issued previously for the project on September 28, 2020. CatDet 2020-002 authorized eight (8) maintenance and repair activities throughout the Tenant’s leasehold for a period of five (5) years. This amendment is necessary to remove the 5-year time constraint and to clarify a reduction in scope of maintenance and repair activities to be included in the Project from this point on. As amended below, five (5) of the original eight (8) activities would continue to be permitted through this amendment to approvals for Project No. 2020-002. The facility maintenance, repairs, and removal activities proposed by the Project would not change or expand the nature or intensity of existing uses at the Tenant’s site. Activities that are proposed to fall under this Project include the following: • Under-pier steel pipe replacements; • Electrical equipment and conduit repairs; • Concrete repairs for piers; • Welding, Concrete Repairs, and sheet pile repairs; and • High-density polyethylene saltwater fire main piping and concrete ballast repair. The specific activities proposed, as outlined below, are more particularly described in the permit application materials submitted by the Tenant to the District. Per the conditions of the amended District Conditional Project Approval (DCPA) for the proposed Project, the Project must comply with the construction methods, Best Management Practices (BMP), and standards identified in the application material, which are on file with the District. Notwithstanding inclusion in any application materials, no maintenance or other construction activities not specifically identified in this Project Description and authorized by the DCPA are permitted or approved. Underpier Steel Pipe Replacements The Project proposes to replace approximately 1,000 linear feet of pipe per year. Pipes would be replaced in-kind under the existing piers within the NASSCO leasehold, and would range in size between 0.5 and 14 inches in diameter. Activities are limited to in-kind repair of existing facilities. Typical repairs would include replacement or repair to various pipes, including potable water, oxygen, natural gas, saltwater, compressed air, argon, carbon dioxide, and sewage. Hangers or mechanical fasteners may also be replaced. Pipes may require burial in excavated trenches from the top deck of the pier, outside of the water. Within the landside of the leasehold, trenches would be excavated wide and deep enough to provide 6 inches of clearance on all sides of the pipe. Over excavation would therefore be required, with compaction of the subgrade. Pipes would then be covered with 12 inches of Class 2 aggregate and asphalt concrete (AC) would be placed on top of the Class 2 aggregate on the top of the pier. Construction BMPs, as enumerated below, including but not limited to (1) the use of a scaffolding system or arrangement of floats for containment of debris from deck and underdeck repairs and (2) requiring the removal and proper disposal of all debris generated by construction activities, would be in place during construction, as conditioned in the District Conditional Project Approval (DCPA). No new construction or addition of pipe infrastructure is proposed. Electrical Equipment and Conduit Repair The Project proposes to replace up to 1,000 linear feet of conduit pipe per year. Construction BMPs, as enumerated below, including the use of a scaffolding system or arrangement of floats for containment of debris from deck and underdeck repairs, would be in place to ensure not all debris is collected and prevented from entering the water. Activities are limited to in-kind repair of existing facilities. Typical maintenance or repair generally includes replacing feeders to existing conduits, encased duct banks, pull boxes, termination boxes, and an array of various electrical components (e.g., switchgear, substation, gas switch, new wire way, and cable tray). No new construction or addition of electrical infrastructure is proposed. Concrete Repairs for Piers Repairs would consist of traditional concrete repair methodologies using cementitious repair materials and formwork. Construction BMPs would be in place to ensure there is no bottom disturbance, all debris is collected, and no cementitious material enters the Bay. Repairs to concrete structures would include the following: • Underpier concrete repairs (concrete patching of degraded or worn areas, and covering with fiber-reinforced plastic [FRP] fabric to protect against corrosion); • In-kind replacement of concrete platform slab and soffit; and • Concrete pile repairs (filling cracks with epoxy and wrapping with FRP fabric to protect against corrosion). Resulting repairs would not result in any expansion to piers or piles, and no new piers or piles are proposed. Welding, Concrete Repairs, and Sheet Pile Repairs Ongoing repair and improvements to the existing Graving Dock, Ways 3 and Ways 4 Gate, Concrete Horizontal Sill and Vertical Abutments, as well as the associated Steel Sheet Pile Bulkhead are anticipated at the NASSCO shipyard. The Project proposes the following: • Repairs of up to 500 linear feet per year of the steel gate, this would be completed by welding new pieces of steel to the damaged section of the Gate and/or Bulkhead; • Repairs of up to 1,000 linear feet per year of the concrete horizontal sill and vertical abutments; and • Repairs of up to 1,000 linear feet per year of the bay-side steel sheet pile bulkhead wall. To complete these repairs dewatering would be accomplished through use of a localized cofferdam installed directly to the Gate and/or Steel Sheet Pile Bulkhead and sealed at the interface seam with a moldable polymer typically used for marine sealing applications. The cofferdam would either sit directly on concrete (the Graving Dock or Ways floor) or be anchored to the pile cap and would not result in any disturbance to the Bay bottom. Resulting repairs would not result in any expansion to areas of work, and no new facilities are proposed. High-Density Polyethylene Saltwater Fire Main Piping and Concrete Ballast Blocks Repair The Project proposes to repair an estimated 1,000 linear feet of pipe and 10 concrete supports per year. Maintenance and repair are limited to in-kind repair of existing facilities (e.g., repairs on existing fire main piping and concrete ballast repair. Divers would cut the targeted areas of the fire main piping and remove bolts from the concrete ballasts. A barge-mounted or landside crane would assist with the piping and concrete ballast removal process. A barge would be staged at the immediate work area for laydown and piping component field preparations. Removed piping components would be disposed of offsite. During the installation process, divers would be assisted by a barge-mounted or landside crane. Resulting repairs would not result in any expansion fire main or ballast block systems, and no new fire main or ballast block systems are proposed. Best Management Practices and Federal and/or State Permit and Authorizations: The proposed project must obtain all necessary regulatory permits prior to implementation, including Clean Water Act (“CWA”) Section 404 (Army Corps of Engineers) and Section 401 (Water Quality Certification, Regional Water Quality Control Board) approvals from applicable regulatory agencies. The project applicant is required to adhere to all conditions and standards identified in those permits. Additionally, the applicant may also be regulated under California’s Porter-Cologne Water Quality Control Act, which requires the Regional Water Quality Control Board (Regional Board) to prescribe waste discharge requirements (WDR) for any proposed or existing discharge unless WDRs are waived consistent with Water Code Section 13269. The Section 401 Water Quality Certification (401 Certification), to be reviewed and approved by the Regional Board, certifies that the discharge proposed will comply with applicable water quality requirements, standards, limitations, and restrictions, including: (1) CWA Section 301 (Effluent Limitations, (2) CWA Section 302 (Water Quality Related Effluent Limitations), (3) CWA Section 303 (Water Quality Standards and Implementation Plans), (4) CWA Section 306 (National Standards of Performance), (5) CWA Section 307 (Toxic and Pretreatment Effluent Standards). When considering an application for a 401 Certification, the Regional Board considers water quality standards such as beneficial uses (the uses of water necessary for the survival or well-being or people, plants, and wildlife, as designated in the applicable Water Quality Control Plan), water quality objectives (constituent concentrations, levels, or narrative statements representing water quality), and antidegradation policy (protecting existing water qualities). Thus, the Regional Board is charged with ensuring that discharges meet all applicable water quality standards. The Porter-Cologne Water Quality Control Act requires any person who proposes to discharge waste that could affect the quality of waters of the state to submit a report of waste discharge. It also authorizes the Regional Board to propose and issue WDRs that implement a relevant water quality control plan. The Water Quality Control Plan for the San Diego Basin is referred to as the Basin Plan. The Basin Plan designates beneficial uses for water bodies in the San Diego Region and establishes water quality objectives and implementation plans to protect those beneficial uses. A project must be undertaken consistent with the applicable requirements of the Basin Plan and to adhere to the water quality objectives within the Basin Plan. The Project applicant is currently seeking the required approvals, which must be obtained before commencement of construction. The San Diego Regional Water Quality Control Board issued a Completeness Review for the Application for the NASSCO General Facility Maintenance and Repairs Project deeming the application for this Project complete. In addition, the following BMPs would be implemented as applicable to the individual components of the Project, as a requirement of the DCPA: • All debris would be removed from the water and disposed of properly. • During construction, the contractor would comply with permit conditions imposed by the U.S. Army Corps of Engineers, Regional Water Quality Control Board, and other regulatory agencies. • Disposal of construction and trash debris into the bay would be prohibited. • All construction-related equipment would be maintained in good-working order to minimize the potential for hazardous waste spills. Current hazardous material spill prevention and cleanup plans would be maintained on site. • All waste material removed from the Project site would be relocated to an approved disposal point. • The contractor would avoid covering and disturbing any low-relief boulders that may support higher numbers of intertidal organisms, where possible. • Consistent with California Coastal Act and California Eelgrass Mitigation Policy, a pre- construction eelgrass and Caulerpa taxifolia survey would be performed in the Project area 30 to 60 days prior to commencement of applicable repair activities. • Equipment operators and all other Project workers would not harass any marine mammals, waterfowl, or fish in the Project area. • A scaffolding system or arrangement of floats will be used for containment of debris from deck and underdeck repairs. Scaffolding will be covered with plywood panels to contain debris, and debris will be removed at end of each shift. • Cementitious repair material will be placed in dry conditions at available low tides. • For repairs below ordinary high water, only materials suitable for use in aquatic environments will be used, including, but not limited to, cementitious grout designed to cure underwater and multipurpose marine epoxy grout and binder. In addition to the above-listed BMPs, the Tenant proposes, and would be required through the DCPA to adhere to the General Guidelines and Construction Methodologies outlined in the application and supplemental materials for each component of the proposed Project. These General Guidelines and Construction Methodologies include, but are not limited to BMPs that ensure acceptable water quality. These General Guidelines and Construction Methodologies are required to be adhered to, but may be supplemented by the RWQCB. A District-wide Eelgrass Survey was conducted by Merkel & Associates in late 2023, which found eelgrass to be present in certain areas throughout the NASSCO leasehold. Applicable in-water work is required to comply with the National Marine Fisheries Service California Eelgrass Mitigation Program (NMFS CEMP). The NMFS CEMP policy requires preconstruction eelgrass surveys for all in-water work. This approval does not allow for any work to be performed if the required preconstruction survey finds potential for impacts to eelgrass. As such, preconstruction eelgrass surveys would be required to be submitted to the District between 90 and 30 days prior to the start of any in water construction in addition to any other agencies as required by the NMFS CEMP and other federal, state, and local regulations. There would be no change in the number of employees, customers, or visitors per day as a result of the Project. All debris would leave NASSCO via truck. Truck trips for the implementation for the Project would be for deliveries and labor and materials transport. Therefore, implementation of the Project would generate a minor amount of additional vehicle trips, and in turn, would not result in any significant impacts related to air quality, greenhouse gas emissions, noise, traffic or other California Environmental Quality Act (CEQA) resource areas. Any trucks that are needed to transport materials to the site and/or transport remnants/debris offsite to the appropriate landfill, would adhere to the existing truck route for the Project site, which prohibits trucks over five tons from traveling on many streets within the Barrio Logan community. Furthermore, the applicant would be responsible for complying with all applicable federal, state and local laws regulating hazards, and hazardous materials and stormwater.

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