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2 Project Description will be to connect via an approximate 2,500 linear-foot above-ground line from the point of connection to a point on the west side of the southwestern boundary of the existing substation. The second option is to enter the substation on the southwestern edge by way of a below ground line as shown in Figure 2-1. The roughly 2,000 linear-feet of underground line would enter the substation somewhere between the western edge and the center of the south boundary of the substation. Either ROW corridor is assumed to be up to 100 feet in width and include a maintenance road. Permanent impacts for the aboveground line would occur associated with the pole pads and access roads and temporary impacts associated with pull and splice sites and overland travel during construction. Associated with trenching to install the ducts, surface construction impacts from the below ground option would be temporary. Permanent impacts would result for the construction of an access road. The above-ground 230 kV gen-tie transmission line would include concrete or steel structures up to approximately 165 feet tall with typical span lengths of 700 feet. The foundation depths are expected to be approximately 30 feet deep and 8 feet in diameter depending on geotechnical conditions. Poles may also be required at the substation terminus for the below ground line if required for interconnection. The poles may be A-frame, H-frame, or monopole or a combination thereof. The poles would carry one conductor per phase and allow the line to maintain a minimum 30-foot vertical clearance to the ground. The number and height of the poles, as well as the type of conductor, will be finalized during detailed design. The Project is expected to have approximately 15 structures. An underground line, if selected, would consist of conductor housed in nine conduits encased in concrete duct banks. The banks would be approximately 4 feet wide buried 7 to 10 feet below ground. The duct bank would have a minimum of 36 inches of cover. The alignment, which would include one vault, would be installed in an open trench. This would include roughly 24 inches of thermal concrete backfill and 12 inches of native fill. Within the Tesla Substation, network upgrades for either option include a grounding system, steel support structures, outdoor lighting, and outlets, and a disconnect switch may be required. Improvements could also include installation of underground conduits, pull boxes, and junction boxes. Civil improvements may include site surfacing and grading would be within the substation. Interconnection facilities to be constructed at the Tesla Substation could include a circuit breaker, disconnect switches, surge arresters, and a dead-end/pull off structure. A line current differential relay scheme and breaker failure and reclosing relays may be installed. Improvements could also include the installation of fiber termination for the gen-tie line. 2.5.3.7 Erosion and Sediment Control and Pollution Prevention Since the construction of the Project would result in disturbance of an area greater than 1 acre, the Applicant would be required to obtain coverage under the State Water Resources Control Board (SWRCB) National Pollutant Discharge Elimination System (NPDES) General Permit for Storm Water Discharges Associated with Construction and Land Disturbance Activities, Order No. 2009-009-DWQ, NPDES No. CAS000002 (Construction General Permit). To enroll under this permit, the Applicant would prepare a SWPPP, which would be based on the final engineering design. The SWPPP would be prepared by a qualified engineer or erosion control specialist and would be implemented during construction. The SWPPP would include BMPs, including Erosion Control, Sediment Control, and Good Housekeeping BMPs. The BMPs would include dewatering procedures, stormwater runoff quality control measures, concrete waste management, watering Griffith Energy Storage Project 2-13 Tetra Tech/SCH 2022120675 Draft Environmental Impact Report August 2023