1 - Introduction 2 - Vision Statement 3 - Land Use 4 - Circulation 5 - Conservation 6 - Noise 7 - Safety 8 - Recreation 9 - Historical 10 - Community Design 11 - Glossary - Maps CHAPTER SEVEN SAFETY ELEMENT Section 65302(g) of the California Government Code requires that general plans adopted by planning agencies include "A safety element for the protection of the community from any unreasonable risks associated with the effects of seismically induced surface rupture, ground shaking, ground failure, tsunami, seiche, and dam failure; slope instability leading to mudslides and landslides; subsidence, liquefaction and other seismic hazards identified pursuant to Chapter 7.8 (commencing with Section 2690) of the Public Resources Code, and other geologic hazards known to the legislative body; flooding; and wild land and urban fires." As required by Section 65302(g), the City of Grass Valley consulted with the Department of Conservation, Division of Mines and Geology (DMG) and the Governor's Office of Emergency Services (OES) prior to completing the Safety Element to obtain information known by and available to these agencies. The Safety Element identifies and describes germane safety-related issues, establishes a goal and objectives related to identified hazards, and establishes policies and implementation measures designed to reduce, eliminate, or avoid risk to persons and property. Safety Goal and Objectives 1-SG Reduce the potential risk of death, injury, property damage, and economic and social dislocation resulting from hazards. 1-SO Assurance of a high level of protection from geologic and seismic hazards for all residents, structures and vital services. 2-SO Reduction of risk from exposure to hazards related to past and present mining, including shafts, tunnels, tailings and toxic materials. 3-SO Reduction of risk from exposure to flood hazards. 4-SO Reduction of risk from exposure to structural and wildlife fires. 5-SO Reduction of risk from exposure to hazardous materials, including contaminated sites. Safety Issues Seismicity Generally, the degree of earthquake hazard is based on the interrelationships between faults, weak geologic materials, and human activity. Faults within California are divided into three categories; prequaternary (older than two million years), quaternary (younger than two million years), and historic (less than 200 years). Faults in the County's western half are prequaternary. Quaternary and historic active faults are found in the eastern portion of the County near Truckee. The western half of the County, in which Grass Valley is located, is in the low intensity zone for earthquake severity. Grass Valley is not within an Alquist-Priolo zone as defined in DMG Special Report 42. The closest active fault is the Cleveland Hill fault near Oroville. However, ground movement can be felt in Grass Valley from earthquakes at intermediate distances (i.e., the Truckee quake of 1968) and from distant earthquakes (i.e., the Winters-Vacaville 1892 event). Subsidence Subsidence consists of surface land sinking into subsurface holes or fissures. Subsidence may be caused by a variety of natural conditions, some in combination with human activity. The primary cause of actual and potential subsidence in the Grass Valley area is previous underground withdrawal of material from mining. Less hazardous and generally better controlled is improper burial of organic materials during land development. Subsidence hazards in Grass Valley and vicinity are principally man-made, rather than natural geologic phenomena, and are addressed under Mine-Related Hazards. Mine-Related Hazards The collapse of the Old Brunswick shaft of the Idaho-Maryland Mine Complex near Grass Valley during the 1998 storm season dramatized the danger to persons and property presented by abandoned mines. In that May, 1998, incident, the sudden subsidence of land above a long-hidden mine entrance claimed property and undercut the foundation of a new home near Grass Valley. Despite its colorful contribution to local history, mining had, and continues to have, a serious "downside" in terms of safety. Unfortunately, the magnitude of potential mine-related problems in the Sierra foothills is just starting to be recognized. That recognition includes an admission by State Mining and Geology experts that little is known about the locations of mine-related hazards, a factor inhibiting comprehensive solutions. Mine-related hazards include the presence of open holes at ground surface; inadequately covered/shored up shafts and tunnels below ground level; tailings, and other abandoned mining features. Safety and hazard concerns resulting from old mine operations include the risk of falling into open shafts, surface collapse/subsidence into old shafts, and the presence of residual toxic materials generated in mining processes. A substantial portion of the Planning Area is underlain by a deep, extensive labyrinth of abandoned mine tunnels. The Empire Mine tunnels alone extend some 365 miles beneath the City of Grass Valley. Literally dozens of mining claims were "worked" in the Grass Valley area during the heyday of gold mining. Some were large, mechanized operations. Most were small and more labor-intensive. Hard- rock mining, as historically practiced in western Nevada County, was also characterized by 1) one or more angular shafts from surface to underground tunnels for transporting miners, equipment, and ore and 2) vertical air shafts from tunnels up to the surface, whose functions were to admit fresh air to the otherwise depleted atmosphere below. Tailings piles (ore storage) and tailings ponds (used in ore processing) were also typical surface features of deep mines. Figure 7-1 shows locations of mine tailings piles in the Planning Area (U.S. Geological Survey data). Figure 7-2 depicts old mining claims in the Grass Valley area. These maps are potential indicators of mine-related hazards, but are by no means definitive guides to where surface hazards do or do not exist. Mines and mining, always dangerous while in operation, posed new dangers when abandoned. Air shafts were left exposed or covered by a few boards. They are typically holes of 4 to 10 feet in diameter on the surface, extending hundreds of feet down to the mine tunnels below. Access shafts were often covered hurriedly by closing off the mine mouth (entrance) with logs, then backfilling with rock and earth. In time, the forgotten-but-"reclaimed" site sprouted vegetation, hiding a large hole lurking perhaps as little as 8 to 10 feet below the surface. The susceptibility of mine shafts to subsidence or cave-ins depends on a number of factors, particularly water content of the soil above and the depth and physical condition of the shaft. The Division of Mines and Geology believes that septic systems contribute to subsidence by keeping otherwise dry soil overburden wet and heavy, thus triggering collapses that might otherwise not occur. The greatest problem regarding mine-related surface hazards is the absence of information about the locations and physical characteristics of abandoned tunnel entrances and shafts. Without such information, it is difficult to assess the magnitude of the problem or to devise remedial programs. Slope Instability Unstable soils and geologic conditions have historically resulted from vegetation removal associated with wildfires, timber harvesting, mining, and grading as part of road and building site development. Depending on local topographic, geologic and hydrogeologic conditions, significant precipitation can exacerbate unstable conditions, resulting in landslides and mudslides. Any area adjacent to a hydraulically mined area is subject to landslide activity due to the removal of supporting rock and soil. Under such conditions, earthquakes or heavy rains can initiate slide activity. Landslides are events in which surface masses of slope-forming earth move outward and downward from their underlying and stable floors in response to the force of gravity. Unstable or potentially unstable slopes are susceptible to slide, falls, creeps, or mud flows. Although slope movements can occur in any type of rock material, certain bedrock formations exhibit a high susceptibility to such movement. This type is generally not found in the western portion of the County, but could occur on a local basis. Flooding As indicated by Federal Emergency Management Agency Flood Insurance Rate Maps (FIRM), the City of Grass Valley and the General Plan Planning Area are relatively well drained. The 100-year flood designations are generally confined to narrow bands along local drainages. Few transportation corridors are susceptible to flooding in a 100-year flood event. Idaho-Maryland Road east of SR 49/20 and South Auburn Street south of Whiting Street will be flooded during a 100-year flood. To the extent culverts and storm drains are not maintained, other localized flooding could occur. Structures located in the flood hazard areas would be subject to flooding in a 100-year flood event unless special mitigation is employed. The current FEMA flood map for Grass Valley and vicinity is shown in Figure 7-3. Future development will inevitably result in increased runoff, thus increasing the potential for flooding in natural and man-made drainage ways. Flooding as a result of dam failure can occur as a result of manmade or natural causes. Such causes include improper siting, structural design flaws, erosion of the face of foundation, earthquakes, massive landslides, and rapidly rising flood waters. The only dam capable of inundating a any portion of the Grass Valley Planning Area in event of failure is the Scotts Flat Lake Dam operated by NID. Inundation as a result of dam failure would most likely be the result of an earthquake. However, the area of Nevada County in which these dams exist is not located within an historical seismic zone. In fact, the western half of Nevada County is within the lowest earthquake intensity zone in California. Structural and Wildland Fire Fire protection agencies in the City of Grass Valley General Plan Planning Area include the City of Grass Valley Fire Department, which provides service within the City, the Nevada County Consolidated Fire District, which serves the area generally north, west and south of the City, and the Ophir Hill Fire District, which serves lands east of the City. In 1998, an Automatic Aid agreement was reached among these agencies, which provides for a response by a minimum of two pieces of equipment anywhere in the City within four minutes, 24 hours/day. Otherwise, mutual aid from agencies state-wide is provided pursuant to the California Fire Service and Rescue Emergency Mutual Aid System via its Mutual Aid Plan. The City of Grass Valley maintains the following four fire-fighting facilities, strategically sited throughout the City. The City's current average response time is 4.0 minutes(1) and an ISO rating of 4. The five-year plan is to consolidate the four fire facilities to two locations: Fire Station No. 1 at its existing location to serve the west portion of the City and Fire Station No. 2, a new station located near the Sierra College Campus, to serve the east portion of the City. A third station is tentatively planned in the southern portion of the Planning Area near North Star Drive. A future station could be located within the Loma Rica Industrial Park if and when that area is annexed to the City. The Grass Valley region has a generally high potential for wildland fires of devastating intensity. This is due to the presence, particularly in less urban settings, of heavier timber, woodland and brush, the occurrence of steep slopes, dry weather conditions, and human activity. Generally, vegetative areas of over 8% slope are considered as fire hazardous. The California Department of Forestry and Fire Protection (CDF) provides fire protection for wildland areas, and is legally responsible only for wildland fires, not structural fires, during the fire season. Existing standards for development that are expected to provide adequate access, fire flows, and other facilities to maintain an appropriate level of fire protection will continue to derive from the California Building Code, the California Fire Code, and the California Mechanical Code. The City's municipal water system serves the majority of the City's incorporated boundaries, or approximately 1,357 acres and approximately 60% of the current incorporated area. A few properties outside the City are served, such as the Nevada County Fair Grounds. Under a current agreement, the City purchases raw water from NID and then treats and distributes the water. Of the 250,000 acre feet of water available to NID, about 170,000 acre feet are currently used. The City's treatment facility has the capacity to treat five times the amount of water currently processed. Limitations exist on expansion of the City's water service due to topographical constraints and location of the treatment facility. Due to the location of most reservoirs at 100-200 feet in elevation above the City, the City of Grass Valley water system provides excellent pressure and flows for firefighting purposes. There are isolated areas of inadequate piping and areas that have no hydrants. These areas are being upgraded as the City develops. As the City has expanded its geographic limits, areas served by NID have been incorporated. Emergency Access and Evacuation Routes The City currently maintains approximately 38 miles of roadways, excluding state highways. As do most foothill towns, the City of Grass Valley has comparatively narrow streets in older developed areas. Improvements to roadways, intersections, and off-street parking facilities cited above help alleviate congestion and improve fire access in these areas. Hilly roads slow response times, particularly in snow conditions, although the Grass Valley Fire Department is equipped to deal with these conditions. Nationally recognized standards are used by the Fire Department in planning for new development to prevent access constraints to fire equipment and improve emergency evacuation capabilities. The Safety Element is required by California law to address the subject of evacuation routes, in the event of a catastrophe. Figure 7-4 shows evacuation routes out of Grass Valley and the Planning Area. Primary evacuation routes are the two freeways serving Grass Valley: Highway 49 (toward the north and toward the south) and Highway 20 (toward the west). Secondary evacuation routes are Highway 174 (toward the east), Brunswick Road (toward the east/southeast), McCourtney Road (toward the southwest), West Main/Rough and Ready Highway (toward the west from the northwest portion of the City), Idaho-Maryland Road (toward the east, until and unless the road is closed), Nevada City Highway (toward the north paralleling Highway 20/49 toward Nevada City), and LaBarr Meadows Road (toward the south, paralleling Highway 49 south toward Auburn). In the case of evacuation, officials will direct traffic to proper evacuation routes. Quite naturally, the selection of evacuation routes depends upon the magnitude, type, location, and direction of movement of the catastrophic event. Airports The Nevada County Airpark lies to the east of Grass Valley. The Federal Aviation Administration (FAA) defines the most critical areas as those immediately beyond the runway ends -- the initial climb out and final approach sectors. It is within these approach/departure sectors that the concentration of aircraft accidents occur. In addition, there are studies indicating that about half of all airport accidents occur on airport property and an additional 15% of accidents occur within one mile outside the airport property. This suggests that areas immediately off the ends of the runway and under the airport traffic pattern be carefully evaluated for developed land use. The Foothill Airport Land Use Commission designates airport safety areas. Safety areas for Nevada County Airpark are bordered, but not encroached upon, on the north and south sides by residential developments or industrial buildings. All other safety areas at the airport are surrounded by open space. Figure 7-5, Airport Safety Areas, depicts Airport Safety Area 1 (clear zone), Airport Safety Areas 2, 3, and 4 located adjacent to and extending east and west of the Nevada County Airpark runway, and Airport Safety Area 5, a 5,000' radius from the runway surface. A table entitled Land Use Compatibility Guidelines for Safety lists compatible and incompatible land uses within the various Safety Areas. The Grass Valley City Council adopted the Nevada County Airpark Comprehensive Land Use Plan (CLUP) as City Resolution 89-153 on August 8, 1989. That resolution and CLUP provisions adopted by City Resolution 89-153 contain specific provisions regarding structure height, land use, noise, and safety in the Airpark vicinity. Hazardous Materials The significance of environmental or human exposure to hazardous materials depends on the type, location, and quantity of the material released. In the Grass Valley area, hazardous materials may be transported via roadways, railways, and airways. Industrial facilities that use, store, or dispose of hazardous materials present the greatest potential to toxic exposure due to accidental release. However, most of the hazardous waste stream in Nevada County, including Grass Valley, is generated by "small quantity generators." Hazardous materials and wastes are regulated by federal and state laws and are required to be recycled or properly disposed. Transport of hazardous materials is also heavily regulated. However, illegal storage and disposal and unintentional releases of hazardous materials from leaks and accidents can still occur. Where hazardous materials are found to be illegally stored or otherwise accidentally released, the initial response is provided by the local fire agencies. Site assessment and cleanup is conducted by the Marysville Fire Department, which is operated by CDF. When discovered, fuel storage tank leaks, are cleaned up under the jurisdiction of the California Regional Water Quality Control Board, Central Valley Region. Ten sites are listed in the Solid Waste Facilities, Sites, and Operations Database for the Grass Valley area. These sites include closed, as well as operating solid waste landfills according to an inventory compiled by the California Integrated Waste Management Board. These waste sites are regulated by the State and Nevada County. Naturally Occurring Asbestos Asbestos is a term used for several types of naturally occurring fibrous minerals found in many parts of California. The most common type of asbestos is chrysotile, but other types are also found in the state. Serpentine rock, which has a grayish-green to bluish-black color and an often shiny appearance, often contains chrysotile asbestos and is abundant in the Sierra foothills. Asbestos is not found in all serpentine rock, but when it does occur, it is typically present in amounts ranging from less than 1% up to about 25% or more. Asbestos is released from serpentine rock when it is broken or crushed. This can happen when cars drive over unpaved roads or driveways surfaced with serpentine rock, when land is graded for building purposes, or at quarrying operations. It is also released naturally through weathering and erosion. Once released from the rock, asbestos can become airborne and may stay in the air for long periods of time. Given the proximity of Grass Valley to potential serpentine deposits, it is possible that construction activities and road surfacing could involve asbestos-containing serpentine rock or soils. All types of asbestos are hazardous and may cause lung disease and cancer. The longer a person is exposed to asbestos and the greater the intensity of exposure, the greater the chances for a health problem. The Air Resources Board (ARB) adopted a statewide control measure which prohibits use of serpentine rock for surfacing applications if it has more than 5% asbestos, and requires testing of serpentine material that is sold. Safety Policies This section contains policies to meet the safety goals and objectives and to address safety issues. 1-SP Adopt current uniform codes for new construction. 2-SP Ensure seismic safety and structural integrity in housing and commercial/industrial facilities through code enforcement. 3-SP Develop and implement appropriate flood hazard regulations. 4-SP Based on location or probable need, require development plans in mined areas to include in-depth assessments of potential safety, including mining-related excavations, and health hazards and accompanying mitigation measures. 5-SP Maintain or return to open space lands subject to flooding. 6-SP Incorporate fire hazard reduction considerations into land use plans/patterns, both public and private. 7-SP Identify, maintain, and mark evacuation routes for use in case of disasters or emergencies. 8-SP Assure public awareness of fire-safety measures, including those addressing property maintenance and evacuation. 9-SP Develop and implement fire-safe community design and landscaping standards, construction codes, and property maintenance regulations. 10-SP Adopt and implement appropriate standards for access roads, on-site driveway standards, fuel reduction and emergency water supply. 11-SP Maintain appropriate standards for water supply, pressure and distribution for fire suppression purposes. 12-SP Maintain a high level of inter-jurisdictional cooperation and coordination, including appropriate automatic aid agreements with fire protection/ suppression agencies automatic aid agreements with fire protection/suppression agencies in western Nevada County. 13-SP Continue to implement provisions of the Nevada County Airpark Comprehensive Land Use Plan, and to coordinate as appropriate with Nevada County, Airpark management, and the Foothill Airport Land Use Commission regarding Airpark plans and safety considerations. Safety Implementation Actions and Strategies This section contains implementation actions and strategies designed to carry out the safety goals, objectives, and policies. 1-SI Adhere to the Land Use Plan's compact overall development pattern, including infill (Land Use Element). A compact development pattern reduces total land area needed to accommodate projected development (thus reducing exposure to potential hazards); facilitates quick response to emergencies from established locations, such as fire stations; and allows cost-effective extension of safety-related infrastructure, such as streets, water and storm-water drainage systems. 2-SI Utilize open space/conservation reserves and easements to restrict development in high-risk areas, such as flood-prone areas, airport safety zones, and areas identified as subject to geologic risk. 3-SI Amend land use regulations to allow clustering and density averaging in conjunction with restricted development of potentially hazardous areas. 4-SI Encourage continuity and linkages within the circulation system. Require future developments to provide multiple ingress/egress points, to facilitate emergency vehicle access and mobility, and to facilitate emergency evacuation movements. 5-SI Maintain high standards of fire preparedness, capacity, and response. Assure the City's capability to maintain such standards as areas are annexed. 6-SI Establish a mine-related hazards program, to include the following specific actions. Initiate and maintain a mine hazard data base, incorporating maps, technical studies, and other germane information. To the extent practical and possible, map and describe identified hazards. Coordinate with Nevada County and the State Division of Mines and Geology in mine hazard research and information collection and dissemination. Provide technical assistance and advice to property owners in identifying and mitigating mine-related hazards on their properties. Determine the appropriate extent of geo-technical field investigations and other research required to determine the presence or absence of potentially hazardous mine-related features. Require appropriate field investigations and other research as part of the approval process for new developments, including individual new structures. 7-SI Continue to regulate development within flood prone areas to reduce the risks of flood hazards to life and property. Avoid stream channel modifications. 8-SI Require new developments to utilize on-site storm water detention techniques. 9-SI Establish site development standards designed to minimize the resulting area and percentage of impervious surface. 10-SI Revise flood hazard maps at appropriate intervals, to reflect the effects of land use changes subsequent to previous flood hazard studies. 11-SI Incorporate into City construction codes appropriate provisions and revisions of the Uniform Building Code regarding seismic safety. 12-SI Maintain an active code enforcement program to assure the safety of residential and commercial structures. 13-SI Require new developments located on officially identified hazardous waste sites to conduct appropriate investigations, submit results to the City, and prepare a mitigation plan as part of the project review process. 14-SI Enforce provisions of the Nevada County Airpark Master Plan, Nevada County Airpark Comprehensive Land Use Plan, and City Council Resolution 89-153 (General Plan amendment GPA89-01) regarding development in designated Airport Safety Areas. 15-SI Mark evacuation routes with visible signage. 16-SI Establish and maintain public information and awareness programs regarding public safety and hazards, in cooperation with appropriate emergency agencies and organizations. 17-SI Consider the location and characteristics of documented hazardous waste sites as part of the environmental assessment process for proposed developments. 1. 1 Response time is defined as average response from notification to service provision at incident location.