SCH Number 2020100168
- NASSCO Facility Maintenance Project
- 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 be conducted over a 5-year period to facilitate and streamline the permitting requirements for each activity presented. 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: • Maintenance dredging; • Under-pier steel pipe replacements; • Electrical equipment and conduit repairs; • Quay wall repairs; • Concrete repairs for piers; • Welding, Concrete Repairs, and sheet pile repairs; • Fender pile replacement; 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 District’s 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. Maintenance Dredging The Project proposes maintenance dredging of a maximum of 50,000 cubic yards of sediment per year over five years to be evaluated based on vessel depth requirement and shoaling. Dredging is proposed in areas that were previously dredged and authorized by the U.S. Army Corps of Engineers (USACE) and the Port to the extent of known records. The Project proposes to designate the authorized depths in each area of dredging by defining the authorized depth based on the current use of the facility and the ships that have either been constructed or repaired at the NASSCO facility, and by reviewing previously authorized dredging Projects to better understand to what depths the area within the leasehold was dredged. This would include recently completed Projects, such as the sediment remediation Project completed in 2015 and the maintenance dredging completed in 2018 and 2019. Facility-wide maintenance dredging is not proposed to exceed depths of -37 feet mean lower low water (MLLW), with 2 feet of allowable overdredge. This depth is consistent with maintenance dredging that has occurred in the past, including most recently in 2018 as part of the NASSCO Maintenance Dredging at Pier 12, the Dry Dock Sump and Berths IV and V project. Dredging of the drydock sump is not proposed to exceed depths of -55 feet MLLW, with 2 feet of allowable overdredge. This depth is consistent with previously approved depths and supported by the Coastal Development Permit issued by the District on February 16, 1983 (Clerks Doc. No. 15635) for the NASSCO Floating Drydock project approval. No new areas of dredging are proposed. Sediment would be dredged using mechanical equipment and placed into a scow for transport to a Sediment Management Area (SMA). The SMA would be located within the existing leasehold for sediment handling and management prior to hauling material to an approved landfill. The likely location of the SMA would be Berth II or Pier 12. A spill plate (also known as a drip catcher) would be used at the SMA to eliminate sediment from re-entering the Bay during offloading. All sediment handling and management would comply with applicable regulations and standards, including implementing best management practices as required by the District’s Jurisdictional Runoff Management Program (JRMP). The JRMP mandates that project applicants implement minimum construction BMPs to comply with the requirements of applicable water quality permits and regulations. Chapter 5 of the JRMP, Construction Component, identifies those BMPs to be implemented during projects that could contribute to pollutants from sediment, debris, hazardous materials concrete and slurry, wood projects, and recyclable materials. A long reach excavator would remove sediments from within the scow and placed into hauling trucks for disposal at an approved landfill and would adhere to Port-designated truck routes. This project does not propose ocean disposal for any dredge material. Amendments, such as Portland cement, may be added to the sediments to remove free liquids and pass a paint filter test. The paint filter test is required by the landfills for permit compliance. Underpier Steel Pipe Replacements The Project proposes to replace approximately 1,000 linear feet of pipe per year over five years. 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 Maintenance 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 of up to 1,000 linear feet of conduit pipe per year over five years. 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. Quay Wall Repairs The Project proposes to repair or replace up to 1,000 linear feet per year over five years of shoreline riprap and concrete repair along NASSCO quay walls. Construction BMPs, as outlined below, including the use of debris curtains, would be in place. Maintenance and repair are limited to in-kind repair of existing shoreline revetment. The contractor would provide temporary shoring to the seawall during the duration of construction, adhering to typical shoring practices. In areas where slope stabilization is required, Construction BMPs, as enumerated below, including but not limited to, (1) not covering or disturbing any low-relief boulders, where possible and (2) requiring the removal and proper disposal of all debris generated by construction activities, would be in place during the grouting and slurry concrete fill process, as conditioned in the District Conditional Project Approval (DCPA). Resulting repairs would not result in any expansion to the quay walls, and no new quay walls are proposed. Concrete Repairs for Piers Repairs would consist of traditional concrete repair methodologies using cementitious repair materials and formwork, over the course of five years. 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 over a 5-year span: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. Fender Pile Replacement Replacement of corroded steel H-piles and associated timber assemblies along fender pile systems at piers and berths within the NASSCO leasehold. H-piles would replace either the existing corroded H-piles in-kind or would replace the existing corroded timber fender piles with H-piles. Up to 70 piles and 1,000 linear feet of treated timber would be replaced per year over 5 years. While the specific piles to be removed have not yet been identified because qualification for replacement is dependent on the quality of individual piles, the replacement of fender piles will result in an overall reduction of fill within the NASSCO leasehold. H-piles utilize less cross-section area than timber piles, therefore, the replaced H-pile would occupy less area than the existing timber fender piles, resulting in a net negative area of fill, as no additional piles are proposed. Additionally, replacement H-piles would utilize the same cross-section area as the existing H-piles, therefore, the replaced H-pile would occupy the same area as the existing timber fender piles, resulting in a net zero area of fill, as no additional piles are proposed. . Construction BMPs, as conditioned in the DCPA, would be in place to minimize bottom disturbance and ensure all debris is collected. Resulting replacement of fender piles would not result in any expansion of fender systems, and no new fender systems are proposed. Fender piles would be removed by dry-pulling the piles from a crane positioned on a barge, using a vibratory hammer, or cutting the piles off at the mud line. Jetting to facilitate pile removal would not occur for this Project. The ultimate method of removal would be determined by the contractor during construction and would be specific to each fender pile being removed. Piles that are removed would be disposed of offsite; broken treated timber would be cut up and stockpiled on site for disposal off site. New H-piles would be installed with an impact or vibratory hammer. 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 over 5 years. 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, including dredging, 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 component 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 proposed 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. • A silt curtain will be used during pile removal to contain turbidity. • A double silt curtain will be used during dredging to contain turbidity. • The contractor may utilize portions of the pier as lay-down during pile and replacement during pile and fender replacement, these activities will use existing facility stormwater BMPs. • 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. In order to identify locations of existing eelgrass habitat, a Baseline Eelgrass Survey was conducted by Merkel & Associates in September 2019. The 2019 Baseline Eelgrass Survey is available with the Development Services Department at the San Diego Unified Port District, located at 3165 Pacific Highway, San Diego, CA 92101. All in water work would be required through the DCPA and other state regulations 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. Furthermore, no dredging is proposed in this Project, or permitted to occur, in areas of known eelgrass habitat. While the 2019 Baseline Eelgrass Survey shows there are eelgrass beds within the NASSCO leasehold, there is no eelgrass within the Project’s proposed dredging footprint, only temporary placement of barges may occur within the eelgrass footprint, and the construction methods and best management practices, as conditioned in the DCPA would not result in an impact to eelgrass. Furthermore, eelgrass is not known to typically be present in marine areas deeper than 15 feet, which is significantly shallower than the areas proposed for dredging. To determine whether there is known eelgrass habitat within the proposed quay wall repair areas, a Baseline Eelgrass Survey was conducted by Merkel & Associates in September 2019. While the eelgrass survey shows there are eelgrass beds within the NASSCO leasehold and specifically, in areas surrounding the quay walls, construction methods to accomplish quay wall repairs and best management practices, as conditioned in the DCPA would not result in an impact to eelgrass. Based on the frequency of vessels coming in and out of the active marine terminal area and the anticipated level of noise generated from limited and temporary Project related in-water pile driving activities, underwater noise from vessels moving in and out of the bay and the existing active marine terminal area would be comparable to the temporary underwater noise generated from Project related in-water pile driving activities. The movement of vessels within the existing marine terminal area would mask the Project-related pile driving sound because Project-related pile driving sound would generate the same or less amplitude than typical vessel noise for those in the active marine area. It is anticipated that construction of the Project would occur in 2020 and would occur over the course of approximately five (5) years. There would be no change in the number of employees, customers, or visitors per day as a result of the Project. All pile debris would leave NASSCO via barge, and all other 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.
2 documents in project