4.5 GEOLOGY AND SOILS

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1 4.5 GEOLOGY AND SOILS INTRODUCTION This section addresses the potential for the Proposed Project to impact the geology and soils in and around the Proposed Project location. Following an overview of the environmental setting in Section and the relevant regulatory setting in Section 4.5.3, project-related impacts and recommended mitigation measures are presented in Section and Section 4.5.5, respectively ENVIRONMENTAL SETTING Regional Setting The project site is located in the Cascade Range geomorphic province of California, which lies between the Klamath Mountains and Sierra Modoc Plateau provinces north of the Sierra Nevada province in the northernmost portion of California (CGS, 2002). The Cascade Range province is characterized by volcanoes, in addition to being in a region of high seismic activity (USGS, 2014). This region is typically underlain by lava and volcanic debris formed by thousands of small, short-lived volcanoes (NPS, 2014). The Cascade Range first appeared in the late Eocene (36 million years ago [MYA]), with the major peaks visible today created since the Pleistocene (1.6 MYA) (USGS, 2014). Siskiyou County (County) is comprised of the Modoc Plateau and Klamath Mountains geomorphic provinces in addition to the Cascade Range province (CGS, 2002). These provinces are similar to the Cascade Range province, in that they are characterized by volcanic activity. The Modoc Plateau province contains occasional lakes, marshes, and streams, as well as north-south faults. The Klamath Mountains province is similar to the Sierra Nevada, with rugged topography and prominent peaks and ridges reaching 6,000 to 8,000 feet above mean sea level (amsl). The project site is located southwest of Mt. Shasta, which has erupted every 600 to 800 years in the past 10,000 years (USGS, 2012). The project site is located in an area predicted to have moderate mud flows as a result of volcanic activity at Mt. Shasta and Shastina (City of Mt. Shasta, 2007). Site Topography Elevations at the project site range from approximately 3,640 to 3,800 feet amsl, with higher elevations to the west towards Spring Hill and northeast towards Mt. Shasta (USGS, 2015). The central project site was originally graded and developed during the construction of the water bottling facility (Plant) in The elevation of the Plant was graded to be 30 feet lower than the elevation of Ski Village Drive to shield views of the warehouse and other ancillary structures (Geosyntec, 2013). The surrounding topography is characterized by similar terrain and elevation. Regional Seismicity and Fault Zones The Alquist-Priolo Act defines active faults as those that have shown seismic activity during the Holocene period, approximately the past 11,000 years (DOC, 2016). According to the United States Geological Survey (USGS), and as shown on Figure 4.5-1, the nearest fault is an unnamed fault located AES Crystal Geyser Bottling Plant Project

2 N O R T H! Ð unnamed fault Cedar Mountain fault system, Stephens Pass section (Stephens Pass fault) LEGEND UV 263 USGS FAULTS BY ERA 5 <1,600,000 Quaternary <130,000 Quaternary <15,000 Latest Quaternary Macdoel Mount Hebron Cedar Mountain fault system, Cedar Mountain section (East Cedar Mountain fault) Cedar Mountain fault system, Cedar Mountain section Miles UV Montague Cedar Mountain fault system (Mount Hebron fault zone) Grenada 97 Bray Yellow Butte fault Gazelle 5 unnamed fault " Weed 97 unnamed fault " PROJECT SITE 4.60 Miles " " " Miles Mount Shasta 6.73 Miles " Ash Creek fault McCloud UV 89 5 Dunsmuir SOURCE: USGS Earthquake Hazards Program, 7/26/2010; California Geological Survey, 2005; AES, 8/29/2016 Crystal Geyser / Figure Regional Fault Map

3 approximately 4.6 miles west of the project site. Additional faults are located north and west of the project site (USGS, 2016a). The Cedar Mountain fault system, approximately 23.6 miles west of the project site, is the closest active fault to the site, last active in 1978 (Figure 4.5-1). According to the California Geological Survey (CGS; CGS, 2015), the closest Alquist-Priolo fault is the Cedar Mountain section of the Cedar Mountain fault system (see Figure 4.5-1). Seismic Shaking Intensity A common measure of earthquake intensity and effects due to ground shaking is the Modified Mercalli Intensity (MMI) Scale. The range of MMI values and a description of intensity factors are displayed in Table The MMI values for intensity range from I to XII, with intensity descriptions ranging from an event not felt by most people (I) to nearly total damage (XII). Between these two extreme ranges, intensities that range from IV to XI have the potential to cause moderate to significant structural damage. The Richter Scale is a measure of magnitude of an earthquake s seismic energy release, with higher numerical values for stronger earthquakes and the effects associated with each level. The relationship between an earthquake s magnitude (Richter) and intensity (MMI) is shown in Table According to the CGS, a probabilistic seismic hazard map is a map that shows the potential hazards of earthquakes, which geologists and seismologists agree could occur in California. These maps are probabilistic due to the inherent uncertainties of the size, location and the resulting ground motion effects to a particular area of California. The seismic hazard maps are expressed in terms of the probability of exceeding a certain ground motion (how many times the acceleration of gravity). For example, if a location has a 10 percent probability of exceedance in 50 years map, then there is an annual probability of 1 in 475 of being exceeded each year. Engineers use these probability measurements to design buildings to withstand large ground motions; more than what is believed to occur during a 50-year interval, and effectively make buildings safer (CGS, 2016a). Ground motion probabilities are dependent upon site specific soil conditions. According to the CGS Probabilistic Seismic Hazards Map (CGS, 2016a), there is a 10 percent probability that the peak horizontal acceleration experienced at the site would exceed gravity (g) from a seismic event in 50 years (CGS, 2016b; DOC, 2008). The ground-shaking probabilities have associated average peak acceleration rates that correspond to MMI rating between VII and VIII (Table 4.5-1). Earthquakes of these intensity values have the potential to result in damage to structures, and would be felt by all people in the vicinity. Heavy furniture could be disturbed, and structures such as chimneys, factory stacks, and columns could fall. Liquefaction, Slope Instability and Surface Rupture Potential Liquefaction is the sudden loss of soil strength caused by seismic forces acting on water-saturated, granular soil, leading to a quicksand condition generating various types of ground failure. Estimating the potential for liquefaction must account for soil types, soil density, and groundwater table depth, and the duration and intensity of ground-shaking (USGS, 2006). Soils comprised of sand and sandy loams that are in areas with high groundwater tables or high rainfall are subject to liquefaction. The project site is located in an area classified as having a low liquefaction potential (USGS, 2016b). AES Crystal Geyser Bottling Plant Project

4 Intensity Value TABLE MODIFIED MERCALLI INTENSITY SCALE Intensity Description Average Peak Acceleration I Not felt except by a very few persons under especially favorable circumstances. < g II III IV V VI VII VIII IX X XI XII Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing. Felt quite noticeably indoors, especially on upper floors of buildings, but many persons do not recognize it as an earthquake. Standing cars may rock slightly. Vibration similar to the passing of a truck. Duration estimated. During the day felt indoors by many, outdoors by few. At night, some awakened. Dishes, windows, doors disturbed; walls make creaking sound. Sensation like heavy truck striking building. Standing automobiles rocked noticeably. Felt by nearly everyone, many awakened. Some dishes, windows, etc., broken; cracked plaster in a few places; unstable objects overturned. Disturbances of trees, poles, and other tall objects sometimes noticed. Pendulum clocks may stop. Felt by all, many frightened and run outdoors. Some heavy furniture moved; a few instances of fallen plaster or damaged chimneys. Damage slight. Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable in poorly built or badly designed structures; some chimneys broken. Noticed by persons driving cars. Damage slight in specially designed structures; considerable in ordinary substantial buildings, with partial collapse; great in poorly built structures. Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, and walls. Heavy furniture overturned. Sand and mud ejected in small amounts. Changes in well water. Persons driving cars disturbed. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously. Underground pipes broken. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations; ground badly cracked. Rails bent. Landslides considerable from riverbanks and steep slopes. Shifted sand and mud. Water splashed, slopped over banks. Few, if any, masonry structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipelines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly. Damage total. Waves seen on ground surface. Lines of sight and level are distorted. Objects are thrown upward into the air. Notes: g is gravity = 9.8 meters per second squared. Source: Bolt, < g < g 0.015g-0.02g 0.03g-0.04g 0.06g-0.07g 0.10g-0.15g 0.25g-0.30g 0.50g-0.55g > 0.60g > 0.60g > 0.60g TABLE APPROXIMATE RELATIONSHIP BETWEEN EARTHQUAKE MAGNITUDE AND INTENSITY Richter Scale Magnitude Maximum Expected Intensity (MMI) Scale I II III IV V VI VII VII IX 7.0 or higher VIII or higher Source: USGS, 2016c. AES Crystal Geyser Bottling Plant Project

5 Subsidence and Settlement Seismic settlement is the compaction of soil materials caused by ground-shaking or the extraction of underground fluids (water, oil, gas). Settlement can be caused by liquefaction or densification of silts and loose sands as a result of seismic loading. Such settlement may range from a few inches to several feet, and be controlled in part by bedrock surfaces (which prevent settlement) and old lake, slough, swamp, or stream beds which settle readily. Static settlement can occur through increased loading of the surface or subsurface materials, such as that imposed by foundations for structures (Das et al, 1995). Dewatering for excavation and foundation construction can cause settlement of drying subsurface materials by removing fine particles from the soil, by open pumping, and by consolidating compressive silts and clays, or loose sands (Powers, 1992). Surface Fault Rupture Surface ground rupture along faults is generally limited to a linear zone a few meters wide. Because no active faults have been mapped across the project site by the CGS or USGS, nor is the project site located within an Alquist-Priolo Earthquake Special Study Zone, fault ground rupture does not represent a hazard at the project site Soil Resources Soil Types Soil types and their distribution within the project site, depicted in Figure 4.5-2, and were identified through a review of maps provided by the Natural Resources Conservation Service (NRCS). With the exception of urbanized areas where soils typically consist of engineered fill, the NRCS soil characteristics describe native, undisturbed soils. Descriptions of the soil units mapped for the study area are provided below (NRCS, 2016). Deetz gravelly loamy sand, 0%-5% Slopes (125 / 125sc 1 ) This is a deep, somewhat excessively drained soil which generally occurs at elevations between 3,000 and 5,000 feet amsl. These soils comprise approximately 94 percent of the total acreage. The typical profile of this soil is 0 to 7 inches below surface level (bsl) of gravelly loamy sand, 7 to 38 inches bsl of stratified sand to gravelly loamy sand, and 38 to 65 inches bsl of stratified very gravelly sand to gravelly loamy sand. This soil is characterized as having a slight hazard of erosion, a low shrink-swell potential, and being highly corrosive to concrete. The soil unit has been assigned to hydrologic group A, which corresponds to having a high infiltration rate when thoroughly wet. The NRCS farmland classification identifies this soil unit as not being prime farmland. These soils have a water table at least 80 inches below the surface. 1 Deetz gravelly loamy sand represented by 125 and 125sc are the same soil type, but due to the location are covered by different surveys done by the NRCS. Deetz 125sc is part of the Shasta-Trinity National Forest Area, Parts of Humboldt, Siskiyou, Shasta, Tehama, and Trinity Counties, California (CA707) survey, and Deetz 125 is part of the Siskiyou County, California, Central Part (CA602) survey. AES Crystal Geyser Bottling Plant Project

6 LEGEND ap Ð N OR TH! Asta gravelly sandy loam, 15 to 50 percent slopes 125sc l Deetz gravelly loamy sand, 0 to 5 percent slopes 600 oria em ath SOIL TYPES WITHIN PROJECT SITE itt M a Sh st Feet r Eve Om Project Site 125sc - Deetz gravelly loamy sand, 0 to 5 percent slopes Production Well DEX-6! A 125 Rasberry Way Red Bud Dr Oakway Rd 6 Redwood Rd Wertz R d Plant Building Shasta Alpine Dr Ski Village Dr r tte D k Bu Blac 125 Rd Terry Lynn Ave le y St Pine Ridge Ave k nc Hi asta Ski Bowl Dr h nt S Mou SOURCE:USDA SSURGO Soil Survey Data for Siskiyou County, updated ; USDA aerial photograph, 7/2014; AES, 9/16/2016 Shasta Ave Caroline Ave 125 Carmen Dr 2M05 d Crispi R Fee R d Butte Ave Morris S t Regin a to Vista Dr 102 2M1 Crystal Geyser / Figure Project Site Soils

7 Asta gravelly sandy loam, 15%-50% Slopes (102) This soil is a deep, well-drained soil associated with hydrologic group B which has a severe hazard of erosion, a low shrink-swell potential, is moderately corrosive to concrete, and is not classified as prime farmland. This soil comprises approximately six percent of the total acreage and generally occurs between 3,000 and 5,000 feet amsl. Its typical profile includes 0 to 13 inches bsl of gravelly sandy loam and 13 to 60 inches bsl of loam, silt loam, or very fine sandy loam. This soil unit has a water table at least 80 inches below the surface. Soil Erosion Soil erosion is the removal and transportation of soil materials from the ground surface that results in deposition in a remote location. Common mechanisms of soil erosion include natural occurrences, such as wind and storm water runoff, as well as human activities that may include changes to drainage patterns and the removal of vegetation. Factors that influence the rate of soil erosion include the physical properties of the soil, topography and slopes, rainfall and peak rainfall intensity. Erosion and potential project-related impacts due to erosion are discussed in more detail within Section 4.8, Hydrology and Water Quality REGULATORY CONTEXT Federal Federal Earthquake Hazards Reduction Act In 1977, the United States Congress passed the Earthquake Hazards Reduction Act to reduce the risks to life and property from future earthquakes in the United States through the establishment and maintenance of an effective earthquake hazards reduction program (NEHRP, 2016). To accomplish this, the act established the National Earthquake Hazards Reduction Program (NEHRP). This program has been reviewed and reauthorized periodically by Congress, with the last reauthorization occurring in 2004 (NEHRP, 2016). NEHRP s mission includes developing effective practices and policies for earthquake loss reduction, and acceleration of their implementation; improving techniques for reducing earthquake vulnerabilities of facilities and systems; improving earthquake hazards identification and risk assessment methods and their use; and improving the understanding of earthquakes and their effects (NEHRP, 2016). The NEHRPA assigns the Federal Emergency Management Agency (FEMA) several planning, coordinating, and reporting responsibilities. Other NEHRP agencies include the National Institute of Standards and Technology (NIST), National Science Foundation (NSF), and USGS. State Alquist-Priolo Earthquake Fault Zoning Act The Alquist-Priolo Earthquake Fault Zoning Act was passed by the California Legislature to mitigate the hazard of surface faulting to structures. The act s main purpose is to prevent the construction of buildings used for human occupancy on the surface trace of active faults. The act addresses only the hazard of surface fault rupture and is not directed toward other earthquake hazards. Local agencies must regulate most development in fault zones established by the State Geologist. Before a project can be permitted in AES Crystal Geyser Bottling Plant Project

8 a designated Alquist-Priolo Fault Study Zone, cities and counties must require a geologic investigation to demonstrate that proposed buildings would not be constructed across active faults (DOC, 2016). California Seismic Hazards Mapping Act The California Seismic Hazards Mapping Act of 1990 (Public Resources Code [PRC] Sections 2690 to ) addresses seismic hazards other than surface rupture, such as liquefaction and induced landslides. The Seismic Hazards Mapping Act specifies that the lead agency for a project may withhold development permits until geologic or soils investigations are conducted for specific sites and mitigation measures are incorporated into plans to reduce hazards associated with seismicity and unstable soils (CGS, 2008). National Pollutant Discharge Elimination System (NPDES) Permit The State Water Resources Control Board (SWRCB) administers regulations and permitting for the United States Environmental Protection Agency (USEPA; 55 FR 47990) for pollution generated from stormwater under the National Pollutant Discharge Elimination System (NPDES) Permit. There are nine Regional Water Quality Control Boards (RWQCBs) that implement the SWRCB s jurisdiction and require that an operator of any construction activities with ground disturbances of one acre or more obtain a General Permit through the NPDES Stormwater Program. The project site is within the jurisdiction of the Central Valley RWQCB (CVRWQCB). The General Permit requires that the implementations of Best Management Practices (BMPs) be employed to reduce sedimentation into surface waters and control erosion. The preparation of a Stormwater Pollution Prevention Plan (SWPPP) addresses control of water pollution that includes the effects of sediments in the water during construction activities. These elements are further explained within Section 4.8, Hydrology and Water Quality. California Building Standards Code The State of California provides minimum standard for building design through the California Building Standards Code (CBC; California Code of Regulations [CCR], Title 24). Where no other building codes apply, Chapter 18 regulates excavation, foundations, and retaining walls. The CBC also applies to building design and construction in the state and is based on the International Building Code (IBC) used widely throughout the country (generally adopted on a state-by-state or district-by-district basis). The CBC has been modified for California conditions with numerous more detailed and/or more stringent regulations. The state earthquake protection law (California Health and Safety Code Section et seq.) requires that structures be designed to resist stresses produced by lateral forces caused by wind and earthquakes. Specific minimum seismic safety and structural design requirements are set forth in Chapter 16 of the CBC. The CBC identifies seismic factors that must be considered in structural design. Local County of Siskiyou Land Use Element The County of Siskiyou General Plan was adopted in 1980 and was last amended in The General Plan serves as the overall guiding policy document for land use and development within the County by AES Crystal Geyser Bottling Plant Project

9 incorporating standards of population density and building density so that circulation and public-facilities needs can be determined. Additionally, the County General Plan promotes the protection and thoughtful development of natural resources such as timber. The following General Plan guiding and implementation policies associated with geologic hazards are applicable to the Proposed Project. Policy 1 Policy 3 Policy 7 Policy 8 Policy 16 No development will be allowed in identified and potential landslide areas unless certified by a licensed California Geologist as reasonably safe for the development proposed. Proof that an area is reasonably safe from landslide, other than from a licensed California Geologist, can be made by the County Planning Department or the Public Works Department if an on-site field inspection indicates that the area of concern presents no danger of landslide, i.e., obvious mapping error. Specific mitigation measures will be provided that lessen soil erosion, including contour grading, channelization, revegetation of disturbed slopes and soils, and project timing (where feasible) to lessen the effect of seasonal factors (rainfall and wind). Enforce building construction standards (Uniform Building Code 2 ) and public works requirements. Single-family residential, light industrial, light commercial, open space, non-profit, and non-organizational in nature recreational uses, commercial/recreational uses, and public or quasi-public uses only may be permitted, if the area is proven to be less than 30 percent slope. The permitted uses will not create erosion or sedimentation problems. Policy 22 No development may be allowed within the designated floodways, and any development proven to be outside the designated floodway and within the 100-Year Flood hazard boundary shall be in accordance with the requirements of the County s flood plain management ordinance. City of Mt. Shasta General Plan Policies Although the project site is not within the City of Mt. Shasta s (City s) jurisdiction, relevant local goals and polices are listed below as they relate to adjacent and cumulative development in the City. Policy OC-2.1 Require erosion control protection as a part of grading and development plans. Policy OC-6.1 Allow mineral and aggregate resource lands at appropriate locations to be commercially developed for purposes of providing construction material and industrial minerals for the area. 2 In 2000, the Uniform Building Code was replaced by the IBC. AES Crystal Geyser Bottling Plant Project

10 Policy SF-1.1 Identify areas subject to inundation. Implementation Measure SF-1.1(a): Require that the limits of flooding resulting from a one hundred-year storm even be shown on all permit site plans where lands may be subject to inundation. Policy SF-1.2 Develop a program to identify areas subject to flooding. Implementation Measure SF-1.2(a): As studies related to flooding are prepared and submitted for projects, the Department of Public Works shall maintain a file of such reports and maps for public use. Policy SF-2.1 Avoid development in areas of steep slope and high erosion potential. Implementation Measure SF-2.1(c): Ensure that site development on steep slopes is designed to avoid creating areas that may be subject to slippage or movement from storm events. Implementation Measure SF-2.1(d): Encourage the use of density transfer to avoid new private construction in areas of steep slopes or high erosion potential. Policy SF-7.1 Working with the County, identify routes to evacuate area residents for different types of emergencies. Implementation Measure SF-7.1(a): Work with the County to establish emergency evacuation routes in the event of different categories of emergencies: severe rain or snow storm, flood, fire, volcanic, or seismic IMPACTS Method of Analysis This section identifies any impacts to geology and soils that could occur from construction, operation, and/or maintenance of the Proposed Project resulting from all modifications undertaken and proposed by Crystal Geyser Water Company (CGWC) to operate the proposed bottling facilities. This includes all facilities installed by CGWC as shown on Figure 3-4. The environmental setting as it existed in 2013, when CGWC purchased the property, forms the baseline from which impacts associated with prior construction activities are measured and evaluated, and the existing environmental setting (2016) forms the baseline from which proposed construction activities and operation is measured. Because the facilities previously installed by CGWC were installed within paved, graveled, or landscaped areas of the project site, the environmental setting with respect to geology and soils has not changed between 2013 and June Impacts to and from geological resources were analyzed based on an examination of the project site, published information regarding geological hazards of the project area, field studies, and comparison of these factors to the significance criteria listed below. If significant impacts are likely to occur, mitigation measures are included to increase the compatibility and safety of the Proposed Project AES Crystal Geyser Bottling Plant Project

11 and to reduce impacts to less-than-significant levels. Impacts that were determined to be less than significant in the Initial Study do not warrant further analysis and are not discussed within this Environmental Impact Report (EIR; refer to Appendix C). The potential for impacts associated with geology and soils resulting from off-site sewer improvements in South Old Stage Road is addressed below. The potential for environmental impacts from the off-site improvements described in Section 3.7 that would serve the Proposed Project, but would occur with or without the Proposed Project, is analyzed in Section 4.12, Utilities. Environmental effects from the planned City of Mt. Shasta State-Mandated Wastewater Treatment and Outfall Improvement Project are discussed in Section , Impact Environmental effects from the proposed Lassen Substation Project are discussed in Section , Impact Thresholds of Significance Criteria for determining the significance of impacts to geology and soils have been developed based on Appendix G of the California Environmental Quality Act (CEQA) Guidelines. Impacts to geology and soils would be considered significant if the Proposed Project would: Expose people or structures to potential substantial adverse effects, including the risk of loss, injury, or death involving: o o o o Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault; Strong seismic ground shaking; Seismic-related ground failure, including liquefaction; Landslides. Result in substantial soil erosion or the loss of topsoil. Be located in 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. Be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code (1994), creating substantial risks to life or property. Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater. Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state. Result in the loss of availability of a locally-important mineral resource recovery site delineated on a local general plan, specific plan, or other land use plan. AES Crystal Geyser Bottling Plant Project

12 Effects Found Not to be Significant The Initial Study (Appendix C) concluded that the Proposed Project would have no impact relative to the following two thresholds of significance: Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state. Result in the loss of availability of a locally-important mineral resource recovery site delineated on a local general plan, specific plan, or other land use plan. Therefore, as discussed in the Initial Study, these effects are not considered within this Environmental Impact Report (EIR). Project Impacts Significance IMPACT Mitigation Measures Significance After Mitigation RESULT IN STRUCTURAL DAMAGE AND INJURY FROM SEISMIC ACTIVITY AND RELATED GEOLOGIC HAZARDS Less than Significant None Required Less than Significant Proposed Project The nearest mapped active fault to the project site is the Cedar Mountain fault system located approximately 23.6 miles west of the project site. The project site is not located with an Alquist-Priolo Earthquake Fault Zone (CGS, 2015). The closest faults are more than 130,000 years in age, and located at least 4.6 miles from the project site. Therefore, the risk of fault rupture at the project site is considered minor because of the infrequent nature of activity along nearby faults. Furthermore, compliance with the CBC would require the site s seismic-design response spectrum to be established and incorporated into the design of all new structures. Structures and utilities would be designed to withstand seismic forces per CBC requirements. These construction standards would minimize the seismic ground shaking effects on developed structures. It is anticipated that cut and fill would be balanced on site. Fill materials would be tested to ensure their stability for use on the project site, and placement of fill would be monitored to ensure compliance with all State and local requirements. As mentioned previously, the project site is not located within an Alquist-Priolo Fault Zone and is therefore not susceptible to surface rupture. Additionally, the project site does not have the potential for liquefaction, as the soils on site are sandy with high infiltration rates. The project site is located in an area unlikely to experience strong seismic ground shaking (CGS, 2016b; DOC, 2008). The majority of the project site is slightly sloped (0 to 5 percent), and has a low erosion potential, which indicates a low AES Crystal Geyser Bottling Plant Project

13 potential for landslides. The Asta gravelly sandy loam is more steeply sloped with a severe erosion potential, and therefore more likely to result in landslides. However, the portion of the project site with Asta soils is approximately 6.0 percent and in an area that is not planned for development under the Proposed Project or under any of the wastewater disposal options (1 through 4). Therefore, the Proposed Project would not increase the risk of landslides in the area. Potential impacts from seismic activity are less than significant and no mitigation is required. The project site is located adjacent to Mt. Shasta, but earthquake and ground deformation in the vicinity of the volcano have been negligible in the last few decades (USGS, 2012). Should the volcano erupt again, deposits of ash, lava flows, domes, and pyroclastic flows could endanger infrastructure within the vicinity of the volcano, including the project site. Although volcanic eruptions are difficult to predict, it is expected that if Mt. Shasta were to erupt, the eruption would be preceded by a series of earthquakes over weeks or months, allowing for evacuation of nearby potentially impacted locations, including the project site (USGS, 2012). Mt. Shasta s most recent eruption was years ago, and on average Mt. Shasta is expected to erupt every years (USGS, 2012). Therefore, it is not expected to erupt for another 300 to 1,000 years. Due to the large timescale of these potential events, this is not considered a reasonably foreseeable event. Furthermore, the City has addressed evacuation procedures in its Emergency Plan, should any volcanic activity threaten the planning area. Therefore, the project would have a less-than-significant impact with respect to seismic activity and geologic hazards. No mitigation would be required. Off-Site Sewer Improvements (Options P1 and P2) The location of the off-site sewer improvements is approximately 1.8 miles south of the project site. This location would be more than 4.6 miles from the nearest Quaternary fault, and more than 23.6 miles from the nearest Alquist-Priolo fault zone. Additionally, the off-site sewer improvements are not within a designated Alquist-Priolo fault zone. Therefore, impacts at the off-site sewer improvements location from seismic activity and related geologic hazards would be less than significant, similar to those of the Proposed Project. No mitigation would be required. Significance IMPACT Mitigation Measures Significance After Mitigation RESULT IN ACCELERATED RUNOFF, EROSION, AND SEDIMENTATION Significant MM 4.5-1: Erosion Control Plan MM S-4.5-1: Off-Site Improvements Erosion Control Plan Less than Significant Proposed Project Previous Construction Activities Past construction included landscaping, water storage tanks, concrete pads, cooling towers, transformers, juice unloading station, CO2 and nitrogen tank, vaporizers, propane tank, and equipment AES Crystal Geyser Bottling Plant Project

14 installed within the existing plant building, as shown in Figure 3-4. These improvements occurred on paved or previously disturbed areas, which required minimal grading and minimal, if any, alterations to on-site drainage. CGWC implemented mitigation measures in accordance with the 1998 Mitigation Agreement between Dannon and the County described in Section 3.6; thus, the following construction best management practices were implemented during construction of the previously constructed facilities: Develop and implement an Erosion Control Plan (ECP) in coordination with the CVRWQCB through the Section 401 process in obtaining the stormwater management approval for the project. At a minimum, the plan will contain the following best management practices: o o o o o All ground-disturbing activities will be limited to the dry season (mid-may through mid- October) to the extent possible. Disturbance adjacent to all drainages that ultimately drain to North Fork Cold Creek will be limited, and vegetation left in place to the degree possible to reduce potential sedimentation All stockpiled material will be placed such that potential erosion is minimized. Filter fabric, straw bales, and/or sediment basins will be used to reduce erosion and the potential for in-stream sedimentation. Seeding and revegetation will be initiated as soon as possible (timed properly to coincide with fall/winter precipitation) after construction completion. Implementation of the ECP reduced the potential for accelerated runoff, erosion, and sedimentation. As a result, impacts associated with previous constructions activities are less than significant. Proposed Project Future Construction Activities Construction of the ancillary components of the Proposed Project, including the security/caretaker residence, ph neutralization facility, and wastewater treatment infrastructure, would involve minor grading and clearing activities within previously disturbed soils, and areas currently covered with gravel to the south of the Plant within the central project site. Additionally, necessary pipeline installation would involve trenching, pipeline installation, placement of backfill, and paving. Cut and fill quantities would balance on site and the Proposed Project would not require exporting of cut material or importing of fill materials except for potentially importing select backfill material for structure foundations. Approximately 25,600 square feet (sf), or 0.59 acres, would be graded on site. Therefore, an NPDES permit would not be required, as the total grading of the project site would be less than one acre. The areas of soil that would be temporarily disturbed during construction of the Proposed Project would be exposed to potential storm events, which could generate accelerated runoff, localized erosion, and sedimentation. In addition, construction activities could expose soil to wind erosion effects that could adversely affect both on-site and nearby soils. This impact would be significant. The majority of soils at the project site, and all soils that would be within the development footprint, are characterized as having only slight erosion hazards. Upon completion of the Proposed Project, structures, gravel, or revegetated areas would eventually cover soils exposed during construction. With the implementation of Mitigation Measure 4.5-1, which would require construction contractors to install erosion and sediment control measures, the impact would be reduced to less than significant. AES Crystal Geyser Bottling Plant Project

15 Wastewater Treatment Option 4 In addition to the impacts described above, Wastewater Disposal Option 4 has further potential for impacts associated with accelerated run-off and erosion, as under this option treated industrial water would be discharged either to an on-site leach field or to an on-site irrigation system (see Section ). Under Wastewater Treatment Option 4, a mainline would be installed via trenching to the two proposed irrigation areas (see Figure 3-11), the lateral pipelines from the mainline to the sprinklers would be installed at ground level and, therefore, would not require any ground disturbance. The irrigation system would be used from May through October, and the leach field would be used at other times. This seasonal use of the irrigation system would ensure that discharge via the system does not overlap with months with high rain potential. Additionally, irrigation sprinkler use would be rotated approximately every two hours to allow for maximum infiltration and to decrease overland flow due to oversaturation of the soil. Furthermore, the sprinklers are sized appropriately for the vegetation existing on the project site (see Appendix J for details). Due to the design of the irrigation system, which includes appropriately sized sprinklers and intermittent use of sprinklers aligning with the dry season, the complete infiltration of irrigation water would be encouraged, runoff would be minimal, and erosion due to irrigation watering under Wastewater Treatment Option 4 would be less than significant. Off-Site Sewer Improvements (Options P1 and P2) Construction of the off-site sewer improvements would occur on previously disturbed and paved soils. There would be no increase in runoff due to the off-site improvements. However, during construction, erosion could occur as soils are displaced and result in a significant impact. Mitigation Measure S would require erosion and sediment control measures at both the project site and at the off-site improvement area and reduce the impact to less than significant. Significance IMPACT Mitigation Measures Significance After Mitigation RESULT IN STRUCTURAL DAMAGE AND INJURY FROM CONSTRUCTION ON EXPANSIVE SOILS Less than Significant None Required Less than Significant Proposed Project Expansive soils have the potential to compromise the structural integrity of proposed new facilities and roadways. Soils with high shrink-swell potentials are considered to be expansive soils. The project site contains Deetz gravelly loamy sand, and Asta gravelly sandy loam which have low shrink-swell potentials. Therefore, on-site soils are not considered expansive soils, and damage or injury during seismic events due to expansive soils would not occur. Furthermore, all structures within the Proposed Project would be designed to withstand settlement impacts resulting from unstable soil conditions and would be in compliance with IBC requirements. Due to the low shrink-swell potential of on-site soils, the Proposed Project would not result in structural damage or injury from construction on expansive soils. This impact would be less than significant and no mitigation would be required. AES Crystal Geyser Bottling Plant Project

16 Off-Site Sewer Improvements (Options P1 and P2) The shrink-swell potential of the off-site sewer improvements area is low to moderate, depending on depth (NRCS, 2016). Soils from 11 to 40 inches below ground surface (bgs) have a moderate shrinkswell potential, while soils less than 11 inches and more than 40 inches have a low shrink-swell potential (NRCS, 2016). The sewer pipeline that would be installed would be within the moderately expansive cross-section of the soil. However, it is not expected that the soils would impact the improved sewer line, as the pipeline would be encased in concrete to prevent the pipe from traffic loading. This encasement would also protect the pipeline from expansion or compression of the soils in the 11 to 40 inch zone bgs (see Figures 3-14 and 3-15 and refer to Appendix L). Therefore, this impact would be less than significant and no mitigation would be required. Significance IMPACT Mitigation Measures Significance After Mitigation USE SEPTIC TANKS OR ALTERNATIVE WASTEWATER DISPOSAL SYSTEMS IN AREAS WHERE THE SOILS CANNOT ADEQUATELY SUPPORT THEM Proposed Project Option 1: No Impact Proposed Project Options 2, 3, and 4: Less than Significant None Required Less than Significant Proposed Project The Proposed Project would discharge all domestic wastewater into the City municipal sewer system. Therefore, the Proposed Project would have no impact with respect to domestic water discharge to an alternative wastewater disposal system. As described in Section , several options for the discharge of industrial rinse and process wastewater are being considered for the Proposed Project within this EIR, as discussed below: Wastewater Treatment Option 1: Industrial rinse and process wastewater would be discharged into the City s municipal sewer system with the domestic wastewater. In this case, no alternative wastewater disposal system would be required, and no impact would occur and no mitigation is required. Wastewater Treatment Option 2: Industrial rinse wastewater would be discharged into on-site leach fields, as currently permitted by the CVRWQCB, and industrial process wastewater would be discharged into the municipal system. As the on-site leach field is already in place and authorized to accept industrial rinse wastewater discharge by the CVRWQCB, soils in this location are able to support this method of wastewater disposal. This option would have a lessthan-significant impact and no mitigation is required. Wastewater Treatment Option 3: Industrial rinse wastewater would be discharged to the existing on-site leach field, as described under Option 2, while industrial process wastewater AES Crystal Geyser Bottling Plant Project

17 would be treated on site before also being discharged into the on-site leach field. The leach field is currently permitted to accommodate 72,000 gpd. The existing leach field would be expanded to accept 108,000 gpd to accommodate the additional flows of the Proposed Project. As with Option 2 above, the on-site leach field is pre-existing and authorized to accept wastewater by the CVRWQCB. However, because the water proposed to be discharged to a leach field under Option 3 would be from a different wastewater source and have different water quality than what is currently permitted. The pre-existing Waste Discharge Requirement (WDR) ensured that the soils used for the leach field were appropriate and could accept the required wastewater discharge amount and the existing leach field operated successfully from its construction to the closure of the Plant in A determination regarding the suitability of the soils for the proposed expansion to the leach field will also be made during the permitting process for the proposed change in wastewater disposal. This option would have a less-than-significant impact and no mitigation is required. Wastewater Treatment Option 4: Industrial rinse wastewater would be discharged to the existing on-site leach field, as described under Option 2, while industrial process wastewater would be treated on site and discharged into an on-site leach field, as described under Option 3, or a proposed on-site irrigation system. As with Option 3, the existing leach field would be expanded to accommodate the additional flows of the Proposed Project and a new or modified WDR permit would be required. Discharging treated wastewater through the proposed irrigation system would be supported by the soil system, as on-site Deetz soils are sandy, well-drained, and are characterized by large depths to restrictive features and to the water table (NRCS, 2016; Appendix H). As described under Wastewater Treatment Option 2, the WDR for the Proposed Project will ensure that the soils used for the leach field can accept the required wastewater discharge amount. This option would have a less-than-significant impact and no mitigation is required. A septic system would not be utilized in any of these options, for domestic or industrial wastewater. Under Wastewater Treatment Options 2, 3, and 4, an alternative wastewater disposal system would be used, and as described above, impacts would be less than significant and no mitigation is required. Cumulative Impacts Significance IMPACT Mitigation Measures Significance After Mitigation CUMULATIVE EFFECTS ASSOCIATED WITH GEOLOGY AND SOILS Less than Significant MM 4.5-1: Erosion Control Plan MM S-4.5-1: Off-Site Improvements - Erosion Control Plan Less Than Significant Geotechnical impacts tend to be site-specific rather than cumulative in nature. For example, seismic events may damage or destroy a building on the project site, but the construction of a development AES Crystal Geyser Bottling Plant Project

18 project on one site will not cause any adjacent parcels to become more susceptible to seismic events, nor can a project affect local geology in such a manner as to increase risks regionally. Implementation of future developments in combination with the Proposed Project, including growth resulting from build-out of the City s and County s General Plan, would not result in increased erosion and soil hazards or expose additional structures and people to seismic hazards. Cumulative development projects would be required to incorporate grading/erosion plans and be developed to the latest building standards, while incorporating recommendations from site-specific geotechnical reports prepared for these projects. The City would ensure the implementation of mitigation measures specifically designed to avoid, reduce, or mitigate potential impacts associated with geology and soils for all projects within City limits. Projects outside City limits (such as the Proposed Project) would be required to similarly mitigate potential impacts by the County. Therefore, potential cumulative impacts would be less than significant MITIGATION MEASURES The following mitigation measures shall be implemented to reduce potential impacts associated with the Proposed Project: MM Erosion Control Plan Prior to earth-disturbing activities that require more than 100 cubic yards of excavation or deposition or cover more than 10,000 sf in area, an ECP shall be prepared and submitted to the Siskiyou County Community Development Department for review and approval for the proposed construction activity. The ECP shall be administered through all phases of grading and project construction. The ECP shall incorporate BMPs to ensure that potential water quality impacts during construction phases are minimized. The ECP shall address spill prevention and include countermeasure plans describing measures to ensure proper collection and disposal of all pollutants handled or produced on the site during construction, including sanitary wastes, cement, and petroleum products. The Plan and proposed measures shall be consistent with the County s Land Development Manual and shall include (1) encouraging grading in the dry season, but allowing grading during the wet season (March to May), provided all measures listed below are implemented; (2) protecting all finished graded slopes from erosion using such techniques as erosion control matting and hydro-seeding; (3) protecting downstream storm drainage inlets from sedimentation; (4) use of silt fencing and hay bales to retain sediment on the project site; (5) use of temporary water conveyance and water diversion structures to eliminate runoff into area waterways; (6) the requirement that it is the responsibility of the CGWC and/or Contractor to inspect and repair all erosion control facilities within 24 hours before each forecasted precipitation event and at the end of each work day during the rainy season; and (7) the requirement that it is the responsibility of the CGWC and/or Contractor to inspect the erosion and sedimentation control measures every day of a storm event, immediately after each storm event and that all repairs shall be made immediately when the measures are not functioning as intended. In addition, the CGWC and/or Contractor shall notify the County of any repairs or corrections made to the erosion or sedimentation control AES Crystal Geyser Bottling Plant Project