SU0015801 - Laserfiche WebLink

Home Browse Search

4 Environmental Analysis 4.7 Geology, Soils, and Paleontological Resources constructed in accordance both with San Joaquin County and Alameda County requirements, including the Building Code. In addition, the Project will comply with applicable stormwater and erosion control regulatory requirements and plans as part of Project operations. In addition, no large-scale, ground-disturbing activities are expected to occur during operations. Decommissioning The amount of soil disturbance used during decommissioning would be similar, though probably less than that created during Project construction. This activity would increase the risk of erosion or sediment transport. Without appropriate stormwater control measures, the potential impact could be significant. However, as decommissioning would also disturb more than 1 acre, it would be required (under the Construction General Permit) to prepare and implement a SWPPP with BMPs, similar to the SWPPP that would be implemented during construction. Mitigation Measure GEO-1 (Stormwater Pollution Prevention Plan)would reduce impacts to less than significant. Mitigation: GEO-1. IMPACT 4.7-3: Would the project be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction or collapse? (Less than Significant Impact) Construction The Project facilities are situated near other infrastructure (substation and wind turbines) and based on visual inspection, there is no indication that the ground in the Project vicinity is inherently unstable (Janky 2022). The components to be installed for the Project are relatively common and, from a geology and soils perspective, are minimally invasive. Therefore, the Project's construction is not expected to generate new natural geologic hazards, such as landslides, lateral spreading, subsidence, liquefaction, or collapse, or result in significant impacts on the geology and soils of the Project area. Temporary excavations may be needed during construction that could potentially cave, resulting in on- or off-site ground failure. Foundation excavations to be included with the Project are anticipated to be on the order of 10 feet deep below existing grades. In addition, trenches of similar depth may be needed associated with gen-tie installation. Cut and fill activities needed to prepare terrace surfaces for battery storage units, could result in cuts of up to 70 feet deep and fills of depths up to 40 feet. Although soil conditions may be encountered during drilling for footings that could result in caving, the use of common construction techniques can prevent caving and protect construction and adjacent areas. During drilling, such techniques can include installing manufactured casing to support borehole walls or using viscous, nonhazardous, and biodegradable fluids during drilling to support the borehole walls. Shoring can be used to stabilize trench excavations. The soils present may mandate various types/styles of bracing or excavation support. Although the excavation depth and configuration generally drive any requirement for temporary over- excavation, or permanent slope protection. All prudent and required precautions, consistent with Griffith Energy Storage Project 4.7-18 Tetra Tech/SCH 2022120675 Draft Environmental Impact Report August 2023