CITY OF PLEASANTON, CALIFORNIA COMPREHENSIVE EMERGENCY MANAGEMENT PLAN

ANNEX D

ALL HAZARD VULNERABILITY ASSESSMENT CITY OF PLEASANTON ALL-HAZARD VULNERABILITY ANALYSIS

Table of Contents

INTRODUCTION...... 3 RISK ASSESSMENT ...... 3 Kinds of Hazard ...... 3 Severity of Hazard...... 4 Affect of Hazard...... 4 Impact of Hazard on the Community ...... 4 DEMOGRAPHIC...... 5 LAND USE ...... 5 BUSINESS ...... 5 TRANSPORTATION ...... 5 GENERAL CLIMATE ...... 6 Severe Weather ...... 6 Local Meteorology ...... 6 CRITICAL FACILITIES ...... 6 INVENTORY OF ASSETS AND FACILITIES...... 7 RISK PRIORITIZATION ...... 7 COMMUNITY ASSETS...... 8 NATURAL HAZARDS...... 9 EARTHQUAKE...... 9 Faults...... 11 Earthquake Probability...... 11 Earthquake Probability...... 12 Livermore Earthquake (January 24, 1980) ...... 15 Seismic Ground Response...... 16 Geology...... 16 Liquefaction...... 22 Damage...... 24 Road Closures Predictions ...... 26 Hazardous Materials Problems in Earthquakes...... 42 FLOOD ...... 45 Significant Flood Events...... 46 Flood Loss Estimation ...... 46 HAZUS Loss Estimation Models: Flood...... 46 Local Flood Information...... 47 Flood History...... 47 Principal Flood Problems ...... 48 Principal Flood Problems ...... 49 Flood Protection Measures...... 49 SEVERE WEATHER...... 49 El Niño...... 49 WILD LAND FIRE...... 52 LAND SLIDES ...... 54 Hazards From "Mudslides", Debris Flows...... 56 Debris Flows ...... 56 Rock Slides ...... 58 Local Slide Potential...... 58 MAN-CAUSED HAZARDS...... 59

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DAM FAILURE INUNDATION...... 59 Livermore Valley Watershed...... 60 South Bay Aqueduct...... 61 Del Valle Dam...... 62 Lake Del Valle State Recreation Area...... 63 Dam Failure Inundation Area – Del Valle Dam...... Error! Bookmark not defined. Local Impact...... 64 Hazard Materials Vulnerability Threat Summary...... 65 HAZARDOUS MATERIALS SITES & TRANSPORTATION ROUTES...... 66 Regulatory Agencies ...... 66 Federal ...... 66 State ...... 66 Regional...... 67 Local...... 67 Hazardous Materials Business Plan...... 68 Emergency Response...... 68 Contaminated Site Cleanup...... 68 Hazardous Materials Targets ...... 69 Hazardous Wastes Generated by Businesses...... 69 Household Hazardous Waste...... 69 Medical Wastes...... 69 Hazardous Materials Transportation ...... 70

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City of Pleasanton All-Hazard Vulnerability Analysis Introduction This document describes natural and technological (human-made) hazards, which can potentially impact the people, economy, environment, and property of the City of Pleasanton. It serves as a basis for city-level emergency management programs. It is the foundation of effective emergency management and identifies the hazards that organizations must mitigate against, prepare for, respond to, and recover from in order to minimize the effects of disasters and emergencies. The All-Hazard Vulnerability Analysis is an overview of hazards that can cause emergencies and disasters.

Risk Assessment

Risk assessment answers the fundamental question that fuels the natural hazard mitigation planning process: "What would happen if a natural hazard event occurred in Pleasanton?" Risk assessment is the process of measuring the potential loss of life, personal injury, economic injury, and property damage resulting from natural hazards by assessing the vulnerability of people, buildings, and infrastructure to natural hazards.

Risk assessment provides the foundation for the rest of the mitigation planning process. The risk assessment process focuses attention on areas most in need by evaluating which populations and facilities are most vulnerable to natural hazards and to what extent injuries and damages may occur. It tells you:

• What these hazards can do to physical, social, and economic assets;

• Which areas are most vulnerable to damage from these hazards; and

• The resulting cost of damages or costs avoided through future mitigation projects.

In addition to benefiting mitigation planning, risk assessment information also allows emergency management personnel to establish early response priorities by identifying potential hazards and vulnerable assets.

The preparation of this assessment considers the following:

Kinds of Hazard

Quite naturally, many people are only aware of the most obvious risks, usually as a result of a disaster that affected their community or state in the recent past such as an earthquake or flood. In many cases, however, there are hazards most people are not aware of because they haven't affected the community or state during the lifetimes of current residents.

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Severity of Hazard

It's important to know the location and amount of land area that may be affected by certain kinds of hazards. For example, there may be areas that can be affected repetitively by a hazard in one part of the community (such as floodplains adjacent to streams and rivers) or there may be potential community-wide impacts from events such as earthquakes. A specific type of hazard can have varying effects on the community, depending on the severity of individual hazard events. For example, differences in the depth of floodwaters from discrete flood events will yield corresponding differences in the amount of damages.

Affect of Hazard

An inventory helps identify the assets that can be damaged or affected by the hazard event. For this assessments, the inventory also includes information on special populations and building characteristics like size, replacement value, content value, and occupancy. In many cases, community assets may be vulnerable to more than one type of hazard, so different characteristics of the same asset are considered to understand its vulnerability to each type of hazard. For example, if a building is subject to both floods and earthquakes, the location and elevation of the building are considered to tell how much of its structure and contents will be damaged by flooding. Also considered is the construction of the building and its ability to resist physical damage caused by the anticipated ground movements during an earthquake.

Impact of Hazard on the Community

Hazards create direct damages, indirect effects, and secondary hazards to the community. Direct damages are caused immediately by the event itself, such as a bridge washing out during a flood. Indirect effects usually involve interruptions in asset operations and community functions, also called functional use. For example, when a bridge is closed due to a flood, traffic is delayed or rerouted, which then impacts individuals, businesses, and public services, like fire and police departments that depend on the bridge for transportation. Secondary hazards are caused by the initial hazard event, such as when an earthquake causes a tsunami, landslide, or dam break. While these are disasters in their own right, their consequent damages should be included in the damage calculations of the initial hazard event. Your loss estimations will include a determination of the extent of direct damages to property, indirect effects on functional use, and the damages from secondary hazards for each of the hazards that threaten your community or state.

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Demographic The City of Pleasanton has an estimated population of 67,700, Livermore’s population estimated at 79,000, and Dublin at 32,000. Pleasanton’s location is bounded by Dublin on the north, Livermore to the east, the Sunol Valley to the south and the steep, rugged Pleasanton and Main ridges on the west. Interstates 580 and 680 provide east-west and north-south access, respectively, while both the UPSP and Western Pacific Railroads traverse Pleasanton on the routes from the South Bay to the Central Valley.

Land Use

While the valley areas are rapidly urbanizing, the hill areas surrounding Pleasanton to the west and south and southeast remain relatively free of development. These areas are being scrutinized as possible recreation areas, both developed and wilderness, to meet the needs of the burgeoning San Francisco area populace.

The early settlers of the Pleasanton area were the Spanish, who used the area for livestock grazing. The first land grant of the Pleasanton area was made to Hose Maria Amador, who gave his name to the valley. Subsequently, a small community grew up around the railroads which passed through the valley. On June 18, 1894, the town was incorporated; its population was 500.

Pleasanton has a greater wealth of old buildings than any other community in the valley. Several structures date back to the early settlement of the valley, including the Alviso Adobe on Foothill Road near Bernal Avenue and the Walter Johnson residents on Foothill Road near Castlewood, which were built in 1842 and 1849, respectively.

The Valley was also part of a permanent settlement of Indians who came to the area approximately 4,000 years ago. The Indians, now called the Ohlone, called themselves the People. Their settlements along Pleasanton Ridge and the lagoon were part of the largest concentration of Native Americans in North America. Their remains and relics have been found all around what is now Pleasanton.

Business

Pleasanton's rural character was maintained through the late 1950's while other cities in the Bay Area grew rapidly, often routinely bulldozing blocks of historic buildings in the name of "progress." It was only a matter of time until developers made their move on Pleasanton and the 1960s and '70s brought drastic increases in both our boundaries and population. Located at the intersection of I-580/I680, Pleasanton became a magnet for retail/commercial developers. Several business parks were constructed including Hacienda, which is the largest in northern California. Jobs multiplied rapidly. By the mid 80s, Pleasanton was the third fastest growing city in California based on economic indicators. The city has emerged as a major job center with many corporate businesses moving their headquarters here. Over 3,000 businesses and industries employing over 32,000 people are presently located in Pleasanton.

Transportation

Interstates 580 and 680 intersect at the west end of the city. Interstate 580 feeds traffic from the Bay Area to the Central Valley of California. Interstate 680 feeds traffic from its intersection with Interstate 80, 45 miles southwest of Sacramento, to San Jose, the heart of Silicon Valley.

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The Bay Area Rapid Transit system (BART) is one of the San Francisco Bay Area's most vital transportation links, averaging about 300,000 trips every day. During the peak of the commute across San Francisco Bay, BART carries as many trips as the San Francisco-Oakland Bay Bridge. The BART system represents a public investment currently valued at nearly $15 billion, with immeasurable importance to the local and regional economy. The eastern terminus station for the blue line is at Dublin/Pleasanton. There are 79 trains per day that stop at that station.

WHEELS, operated by the Livermore Amador Valley Transit Authority, serves sixteen local routes serving Dublin, Pleasanton and Livermore. Express connections to Dublin/Pleasanton BART are available. Express Bus service to Silicon Valley and between Walnut Creek and the Tri-Valley area is also available during commute hours.

General Climate

The San Francisco Bay area has a warm, Mediterranean-type climate, characterized by warm, dry summers and mild, wet winters. Pleasanton’s location in an inland valley on the fringe of the bay area lessens the moderating influences of the ocean and bay, giving it greater temperature extremes that its Bay Plain neighbors..

Severe Weather

The Amador Valley rarely experiences severe weather. Thunderstorms occur less than 5 days per year and are not intense; hail occurs even less frequently. Strong winds with gusts to about 60 miles per hour occur a few times each fall and winter, usually following the passage of a low-pressure system. Damage from such winds is rare. Dust devils occur at times on warm summer afternoons. They are limited in extent and usually pass unnoticed.

Local Meteorology

Temperatures in the Amador Valley dip below 32° F in winter and often rise above 100° F in summer. The highest recorder temperature was 115° F and the lowest was 19° F. The annual mean maximum temperature is 72.9° F and the annual mean minimum temperature is 45.3° F. The mean annual precipitation in Pleasanton is 18 inches.

Critical Facilities

Critical Facilities are an inventory of the assets that can be damaged or affected by the hazard event. This inventory also includes information on special populations and building characteristics like size, replacement value, content value, and occupancy. In many cases, community assets may be vulnerable to more than one type of hazard. Facility characteristics have been evaluated to help identify its vulnerability to each type of hazard. For example, if a building is subject to both floods and earthquakes, the location and elevation of the building are considered to tell how much of its structure and contents will be damaged by flooding and the construction of the building and its ability to resist physical damage caused by the anticipated ground movements during an earthquake.

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Inventory of Assets and Facilities

Asset inventory is located at the Police Department, Fire Department and Emergency Operations Center.

Risk Prioritization

The inventory listing was evaluated to determine the “criticality” of each asset and facility. The evaluation was based on a numerical score assigned to 6 categories (and sub-categories). The categories are:

1. Target Criteria Score (based on its susceptibility to a terrorist or WMD attack)

2. System Criteria Score

3. Damage Criteria Score

4. Casualty Potential Criteria Score

5. Risk Criteria Score

6. Consequence and Insurance Services Organization (ISO) Score.

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Community Assets

The Pleasanton General Plan lists the following as vital Community Assets:

Adult Education/Amador HS - 4665 Bernal Avenue Alameda County Health Department - 3730 Hopyard Road Amador High School Tennis Courts - 1155 Santa Rita Road Amador Recreation Center - 4455 Black Avenue Amador Theater - 1155 Santa Rita Road Century House - 2041 Santa Rita Road City Operations Service Center - 3333 Busch Road Community Clubhouse/Amador Park - 4455 Black Avenue County Fairgrounds - 4501 Pleasanton Avenue Cultural Arts Center - 4477 Black Avenue Department of Motor Vehicles - 6300 W. Las Positas Boulevard DublinISan Ramon Sewage Plant - 7399 Johnson Drive Fairlands Park Tennis Courts - West Las Positas Boulevard/Gulfstream Street Field house - 5800 Parkside Drive Fire Station 1 - 4444 Railroad Avenue Fire Station 2 - 6300 Stoneridge Mall Road Fire Station 3 - 3200 Santa Rita Road Fire Department Headquarters 3560 Nevada Street Harvest Park Middle School Gymnasium - 4900 Valley Avenue Historical Society Museum - 603 Main Street Library - 400 Old Bernal Avenue Livermore-Amador Valley Wastewater Management Agency - 7176 Johnson Drive Memorial Gardens/St. Augustine Cemetery - Sunol Boulevard Muinvood Park Tennis Courts 4701 Muirwood Drive Pleasanton Aquatic Center Amador Park - 4455 Black Avenue Pleasanton City Hall - Civic Center - 200 Old Bernal Avenues, 123 Main Street Pleasanton Middle School Gymnasiums - 5001 Case Avenue Pleasanton School Tennis Courts - 4750 First Street Police Department - 4833 Bernal Avenue Post Office - 4300 Black Avenue Pre-School "Gingerbread House" - 4333 Black Avenue School District Office - 4665 Bernal Avenue Pleasanton Senior Center - 5353 Sunol Boulevard Regalia House - 4133 Regalia Court Sewage Treatment Ponds - Near Stoneridge Drive and Johnson Drive Tennis and Community Park - 5801 Valley Avenue Valley Care Medical Center - 5555 West Las Positas Boulevard Zone 7 Administration Building - 5997 Parkside Drive

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Natural Hazards

Earthquake

Earthquakes are sudden releases of strain energy stored in the earth's bedrock. The great majority of earthquakes are not dangerous to life or property either because they occur in sparsely populated areas or because they are small earthquakes that release relatively small amounts of energy. However, where urban areas are located in regions of high seismic activity, damaging earthquakes are expectable, if not predictable, events. Seismic risk is assumed by every occupant and developer in Alameda County because the County is within an area of high seismic activity.

The major effects of earthquakes are ground shaking and ground failure. Severe earthquakes are characteristically accompanied by surface faulting. Flooding may be triggered by dam or levee failure resulting from an earthquake, or by seismically-induced settlement or subsidence. All of these geologic effects are capable of causing property damage and, more importantly, risks to life and safety of persons.

The San Francisco Bay region sits astride a dangerous “earthquake machine,” the tectonic boundary between the Pacific and North American Plates. The region has experienced major and destructive earthquakes in 1838, 1868, 1906, and 1989, and future large earthquakes are a certainty. The ability to prepare for large earthquakes is critical to saving lives and reducing damage to property and infrastructure. An increased understanding of the timing, size, location, and effects of these likely earthquakes is a necessary component in any effective program of preparedness.

A “major” earthquake is defined as one with M≥6.7 (where M is moment magnitude). As experience from the Northridge, California (M6.7, 1994) and Kobe, Japan (M6.9, 1995) earthquakes has shown, earthquakes of this size can have a disastrous impact on the social and economic fabric of urbanized areas. To reevaluate the probability of large earthquakes striking the San Francisco Bay Region, the U.S. Geological Survey solicited data, interpretations, and analyses from dozens of scientists representing a wide cross section of the Earth-science community. The primary approach of this new Working Group was to develop a comprehensive, regional model for the long-term occurrence of earthquakes, founded on geologic and geophysical observations and constrained by plate tectonics. The model considers a broad range of observations and their possible interpretations. Using this model, rates of occurrence of earthquakes and 30-year earthquake probabilities are determined.

Earthquake Size Descriptions Descriptive Title Richter Magnitude Intensity Effects Only observed instrumentally or felt only near the Minor Earthquake 1 to 3.9 epicenter. Surface fault movement is small or does not occur. Felt Small Earthquake 4 to 5.9 at distances of up to 20 or 30 miles from the epicenter. May cause damage. Moderate to severe earthquake range; fault rupture Moderate Earthquake 6 to 6.9 probable. Landslides, liquefaction and ground failure triggered by Major Earthquake 7 to 7.9 shock waves. Damage extends over a broad area, depending on Great Earthquake 8 to 8+ magnitude and other factors.

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The overall energy release of an earthquake is its most important characteristic. Other important attributes include an earthquake's duration, its related number of significant stress cycles, and its accelerations.

Another way to recognize the intensity of an earthquake is to refer to the Modified Mercalli Intensity Scale. This scale was devised before seismographs were invented. The Modified Mercalli Intensity Scale remains useful in plotting maps that show the general range and severity of ground effects, structural damage, personal observation and sensations during an earthquake. The scale is largely dependent upon the observations and reports of victims of an earthquake.

Modified Mercalli Intensity Scale Numerical Code Description I Not felt by people, except under especially favorable circumstances. II Felt only by persons at rest on the upper floors of buildings, some suspended objects may swing. Felt by some people who are indoors, but may not be recognized as an earthquake. The vibration is III similar to that caused by the passing of light trucks. Hanging objects swing. Felt by many people who are indoors and by a few outdoors. At night some people are awakened. Dishes, windows and doors are disturbed; walls make creaking sounds; stationary cars rock noticeably. IV The sensation is like a heavy object striking a building; the vibration is similar to that caused by the passing of heavy trucks. Felt indoors by practically everyone, and by most people outdoors. The direction and duration of the shock can be estimated by the people outdoors. At night, sleepers are awakened and some run out of V buildings. Liquids are disturbed and sometimes spilled. Small, unstable objects and some furnishings are shifted or upset. Doors close and open. Felt by everyone. Many people are frightened and run outdoors. Walking is difficult. Small church bells VI ring. Windows, dishes and glassware are broken. Liquid spills. Books fall from shelves and furniture is moved or overturned. Poorly built buildings may be damaged and weak plaster will crack. Causes a general alarm. Standing upright is very difficult. Persons driving cars also notice the shaking. Damage ids negligible in buildings of very good design and construction, slight to moderate in well-built ordinary structures, and considerable in poorly built or designed structures. Some chimneys are broken. VII Interiors of buildings and furnishings are damaged considerably. Architectural ornaments such as fountains, statues, and gargoyles are damaged. Small slides occur along sand or gravel banks of water channels; concrete irrigation ditches are damaged. Waves form on water surfaces and muddy bottoms become agitated. General fright or panic. Steering cars is difficult. Damage is slight in specifically designed earthquake- resistant structures, considerable in well-built ordinary buildings, poorly built or designed buildings experienced partial collapse. Numerous chimneys fall; the walls of frame buildings are damaged; interiors VIII are heavily damaged. Frame houses that are poorly bolted move off their foundation. Decayed pilings are broken off. Trees are damaged. Cracks appear in wet ground and steep slopes. Changes in water flow and temperature in springs and wells are noticed Panic is general. Interior damage is considerable in specially designed earthquake-resistant structures. Well-built ordinary buildings are severely damaged with partial collapse. Frame structures are thrown out IX of plumb or shifted off foundations. Unreinforced masonry buildings collapse. The ground cracks conspicuously and some underground pipes are broken. Reservoirs are severely damaged. Reservoirs are seriously damaged. Most masonry and many frame structures are destroyed. Specially designed earthquake-resistant structures may suffer serious damage. Some well-built bridges are destroyed. Dams, dikes, and X embankments are seriously damaged. Large landslides are triggered by the shock. Water is thrown onto banks of canals, rivers and lakes. Sand and mud are shifted horizontally on beaches and flat land. Railroad rails are bent slightly. Many buried pipes and conduits are broken. Few, if any masonry structures remain standing. Other structures are severely damaged. Broad fissures, XI slumps and slides develop in soft or wet ground. Underground pipelines and conduits are put completely out of service. Railroad rails are severely bent. Damage is total, with practically all works of construction severely damaged or destroyed. Waves are XII observed on ground surfaces. All soft or wet ground is greatly disturbed. Heavy objects are thrown into the air and large land masses are displaced.

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Faults

A fault is a fracture in the earth's crust along which rocks on opposite sides have moved relative to each other. Active faults have high probability of future movement. Fault displacement involves forces so great that the only means of limiting damage to man-made structures is to avoid the traces of active faults. Any movement beneath a structure, even on the order of an inch or two, could have catastrophic effects on the structure and its service lines.

Major faults are depicted in the picture below. The three major faults from bottom are the Hayward Fault, San Andreas Fault and the Mount Diablo Thrust Fault. Moderate activity along any of these faults has a high probability of causing damage in the Livermore/Pleasanton area.

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Livermore/ Pleasanton CCCooonnncccooorrrddd VVVaaallllleeeyyy FFFaaauuulllttt Area

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Crustal Deformation Instrumentation has been systematically placed in strategic areas along seismically active areas of the Bay Area to detect even minute earth movements. Below shows approximate locations of and types of instruments.

U. S. Geological Survey

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Earthquake Probability

1. There is a 0.62 probability (± 0.1) of at least one magnitude 6.7 or greater earthquake before 2032 within the San Francisco Bay Region. Such earthquakes are most likely to occur on seven fault systems. The probability value also includes a 0.14 chance of earthquakes on other faults in the region.

2. The earthquake likelihood is distributed broadly across the San Francisco Bay Region. Previous studies characterized probabilities along the San Andreas and Hayward–Rodgers Creek Fault systems. New studies included the San Gregorio Fault to the west and several faults to the east. While the urban core remains at high risk, significant earthquake likelihood was identified in two of the most rapidly growing parts of the San Francisco Bay Region. Along the Interstate 680 corridor and in central and eastern Contra Costa and Alameda Counties, the Calaveras, Concord–Green Valley, Mount Diablo Thrust, and Greenville Faults present an aggregate probability of 0.30 for one or more M≥6.7 quakes before 2032. Along the Pacific coast, in San Mateo, Santa Cruz and Monterey Counties, there is a similar aggregate probability (0.29) because of the close proximity of the San Andreas and San Gregorio Faults.

3. The Hayward–Rodgers Creek, San Andreas, and Calaveras Fault systems have the highest probabilities of generating a M≥6.7 earthquake before 2032. These faults pose a direct threat to the cities of San Francisco, Oakland, and San Jose, which ring San Francisco Bay. The Hayward Fault is of particular concern because of the density of urban development along it and the major infrastructure lines (water, electricity, gas, transportation) that cross it.

4. The probability of at least one smaller (M6.0 to M6.7) earthquake in the San Francisco Bay Region before 2032 is estimated to be at least 0.80. Earthquakes of this magnitude can produce significant damage over localized areas.

University of California at Berkeley

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In 1988, the Working Group on California Earthquake Probabilities concluded that for the San Francisco Bay Region, the probability of one or more large (M about 7) earthquakes in the following 30 years was at least 0.5. This conclusion was based on an analysis of information on the earthquake history and behavior of the San Andreas and Hayward Faults. After the1989 Loma Prieta earthquake, a second Working Group was convened and reevaluated the region’s earthquake probabilities in light of that event. By using new information and including the Rodgers Creek Fault, it estimated the 30-year probability to be 0.62. It was recognized that other faults in the region, including the Calaveras, San Gregorio, Concord–Green Valley, and Greenville Faults, also pose a serious danger. However, these faults were not included due to a lack of information.

The present findings are based on geologic, geodetic, and seismologic information, much of it obtained since the 1989 Loma Prieta earthquake. Some of this information was used to form one basis for seismic shaking hazard maps of California. In addition to new data, new ideas of how faults work have emerged, and analysis methods have been refined to more formally incorporate uncertainty and alternative models into probabilistic estimates.

Based on limited data and still-maturing models, the results of the present assessment involve uncertainty. Rupture probabilities for individual fault segments are more uncertain than rupture probabilities for entire faults. The regional probability of 0.62 is more certain still, and has an estimated uncertainty of ±0.1 (one standard deviation). As additional geologic data are obtained about the behavior of San Francisco Bay Area faults, uncertainties are expected to diminish. It is encouraging that the probabilities calculated for the entire region and for large sub-areas within it are stable.

The Association of Bay Area Governments is an accurate resource for Earthquake risk assessment and earthquake mitigation activities for the Bay Area. United States Geological Survey and California Geological Survey are resources for specific technical data regarding seismic activity in the area.

Livermore-Pleasanton Area

Seismic Hazard Map (CALTRANS)

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The above graphic depicts in information listed on the previous page.

University of California at Berkeley

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Livermore Earthquake (January 24, 1980)

At 11 AM on January 24, 1980, the Livermore-Pleasanton area was rocked by a Magnitude 5.8 earthquake. Though not deemed an “significant” seismic event, it caused local damage and disrupted the lives of the area residents. The graphic below depicts the epicenter of the earthquake and the shake intensity.

California State Geological Survey

This earthquake was a result of movement along the Greenville Fault and was felt throughout the Livermore-Pleasanton area.

There were over 20 aftershocks, most ranging in the magnitude 3.0 – 4.0 area over the next three days. General damage included merchandise thrown from store shelves, toppled chimneys, cracked masonry walls, fallen light fixtures and some cracking in a few local roadways (including the main runway of the Livermore Airport). There were no reported injuries or deaths directly attributed to the event.

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Seismic Ground Response

Geology

Earthquakes in the San Francisco Bay Region have their origin in the release of strain energy by the sudden movement of a fault. Strain energy is constantly accumulating in the crustal rocks of the region because of the motion of the Pacific Plate relative to the North American Plate. Most of this relative motion, of approximately 39 mm/year (1.5 inches/year) across the San Francisco Bay Region, is accommodated by slip that occurs episodically on relatively few faults and creates earthquakes.

All ground in the Bay Area was not created equal. A critical factor affecting intensity at a site is the geologic material underneath that site. Deep, loose soils tend to amplify and prolong the shaking. The worst such soils in the Bay Area are the loose clays bordering the Bay -- the Bay mud -- and the filled areas. The type of rock that least amplifies the shaking is granite. The remaining materials fall between these two extremes, with the deeper soils in the valleys shaking more than the rocks in the hills. Most development is in the valleys. The map opposite groups the geologic materials in the region into eight categories, each with similar amplification in earthquakes.

Pleasanton Livermore

U. S. Geological Survey

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As indicated on “Preliminary Maps of Quaternary Deposits and Liquefaction Susceptibility” by the U. S. Geological Survey (previous page), the Livermore-Pleasanton urban area geology is non-specifically made up of the following geological features:

• New Artificial Fill and Gravel Quarry indicated by blues and purples. (Violent shaking with very high liquefaction susceptibility.)

• Young Basin and Stream Terrace Deposits indicated by greens. (Very strong shaking with high liquefaction susceptibility.)

• Younger Alluvial Fan Deposits indicated by Light Tan. (Strong shaking with moderate liquefaction susceptibility.)

• Old Undifferentiated Alluvial Fan Levee Deposits indicated by yellows. (Strong to moderate shaking with moderate liquefaction susceptibility.)

• Ancient Differentiated Alluvial Deposits indicated by browns. (Moderate to light shaking with moderate to low liquefaction susceptibility.)

• Bedrock indicated by white. (Light shaking with low to no liquefaction susceptibility.)

For a more specific breakdown of the geology in the area, refer to the overall Quaternary Deposits Map of the 9-County San Francisco Bay Region.

This graphic depicts general earth movement shaking amplification based on the geology of the area, not the movement along any given fault or the intensity of an earthquake.

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Ground Shaking Intensity

The role of geologic materials in affecting the intensity of shaking has been known for almost 30 years. Several researchers at the U.S. Geological Survey clearly demonstrated this relationship when they examined data from the 1906 San Francisco earthquake in 1975. Other researchers have expanded this effort by examining the relationship between intensity and geologic materials. Although the categories of geologic materials are the same as used in earlier ABAG maps, the extent to which these materials modify the shaking intensity has been changed slightly. These susceptibility categories are quite similar, but not identical, to the categories recently developed for use in site-dependent building code provisions.

The distance-based intensities mapped for each scenario earthquake are increased or decreased based on the shaking amplification potential of each geologic material to produce the final intensity map for each scenario.

Following are a series of Shaking Intensity Maps (as developed by the Association of Bay Area Governments (ABAG). Shaking Intensity is estimated for different scenarios as indicated in the upper right-hand corner of each map.

Greenville Fault Earthquake of Magnitude 6.9

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Northern Calaveras Earthquake of Magnitude 6.8

Concord – Green Valley Earthquake of Magnitude 6.7

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Rodgers Creek Earthquake of Magnitude 7.0

Southern Hayward Earthquake of Magnitude 6.7

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Below is a map showing the shake intensities of the 1989 Loma Prieta Earthquake as felt by residents who used the internet to record their responses. There were a total of 4,653 responses.

The area circled in red indicates the Livermore/Pleasanton area.

California State Geological Survey

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Liquefaction

The City of Pleasanton’s development and population are located in areas of moderate to moderately low damage susceptibility. The area is, however, susceptible to moderate damage resulting from ground failure and liquefaction. Liquefaction is a specialized form of ground failure caused by earthquake ground motion. It is a "quicksand" condition occurring in water-saturated, unconsolidated, and relatively clay-free sands and silts caused by hydraulic pressure (from ground motion) forcing apart soil particles and forcing those into quicksand-like liquid suspension. In the process, ground materials that are normally firm but wet, take on the characteristics of liquids.

Major landslides, settling and tilting buildings on level ground, and failure of water retaining structures have been observed as a result of liquefaction. Central Alameda County has a moderate damage susceptibility. Local ground conditions vary. Sound structures on firm, dry alluvium typically perform well, but water-saturated areas are potentially hazardous. The areas south of the I-580 corridor have a moderate (up to .2% probability) damage susceptibility. Overall performance of buildings in this zone is anticipated to be somewhat less than those located on bedrock. Ground conditions here are more variable. It should be recognized that great earthquakes anywhere in the Bay Area are capable of triggering liquefaction in central Alameda County.

Livermore Pleasanton

Liquefaction Susceptibility (USGS)

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ABAG has provided liquefaction hazard level maps for the Bay Area. There is only one specific map for Pleasanton that shows the liquefaction hazard in the event of a Magnitude 7.1 earthquake on the Hayward fault.

Other maps show the entire Bay Area liquefaction hazard for different earthquake scenarios.

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Damage

In earthquakes, utility pipelines leak and break. The most vulnerable pipelines are typically those carrying sewage because they are made of the most brittle materials and do not have sealed joints. The next most vulnerable are water pipelines. Some pipelines carrying natural gas are also vulnerable, but utilities such as Pacific Gas & Electric are upgrading and replacing vulnerable pipelines.

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Utility pipelines can leak or break due to the passage of earthquake waves through the soil or due to permanent ground displacement (such as faulting, land-sliding or liquefaction). Even though areas susceptible to liquefaction are a relatively small percentage of the areas in which pipelines are located, these liquefaction-susceptible areas have contained a disproportionate number of breaks.

ABAG, in examining pipeline breakage statistics from the Loma Prieta earthquake, concluded that the damage to pipelines in areas mapped as highly susceptible to liquefaction experienced significantly greater damage than areas with lower susceptibility, given similar shaking levels.

First, the number of water pipeline leaks per mile of water pipeline in areas mapped as having high and very high susceptibility to liquefaction was four-to-six times greater than outside of these areas, given equivalent shaking intensities.

Second, the number of leaks per mile of natural gas pipelines was three-to-eleven times greater within the areas mapped as having high and very high susceptibility than outside of these areas, given equivalent shaking intensities. The gas pipeline leaks were predominately in cast iron and other older pipelines that are known to be vulnerable to earthquake effects.

Much of the pipeline damage occurred in areas where no surface expression of liquefaction was observed. Thus, these statistics show increased damage in areas mapped as being susceptible to liquefaction; they do not indicate that the damage was necessarily due to liquefaction. No damage surveys were conducted of sewer lines as a result of the Loma Prieta earthquake, so no statistical data on damage to these facilities are available. However, as stated above, sewer lines probably had more damage than water lines because they are more brittle and do not have sealed joints.

To date, most liquefaction hazard investigations have focused on assessing the risks to commercial buildings, homes, and other occupied structures. However, liquefaction also poses problems for streets and lifelines- problems that may, in turn, jeopardize lives and property. For example, liquefaction locally caused natural gas pipelines to break and catch fire during the Northridge earthquake, and liquefaction- caused water line breakage greatly hampered firefighters in San Francisco following the 1906 earthquake.

Beginning in 1985, PG&E undertook a 25-year, $2.5 billion program, known as the Gas Pipeline Replacement Program (GPRP). As a result of the GPRP, many pipeline upgrades were installed both prior to and following the Loma Prieta earthquake. These upgrades are continuing. The newer pipelines are significantly less vulnerable to earthquake effects, including liquefaction, differential settlement, violent shaking, and ground strain, than the older types of pipe installed 50 - 100 years ago.

Highways, roads, and airport runways buckle. Pavement surfaces can be made impassable for most vehicles, and may need to be replaced. Buckling occurs because of lateral spreading, ground oscillation, and differential settlement.

Caltrans repaired approximately 10.5 miles (17 km) of damaged highway surface following the Loma Prieta earthquake at a cost of approximately $5.5 million. Data on costs of repairs to local roads are not readily available. Road damage information from the Loma Prieta earthquake indicates that the percentage of highway road surfaces repaired for strong and very strong shaking intensities (MMI VII and VIII) ranges from 1.4 to almost 12 times greater for areas mapped as having very high liquefaction susceptibility than for areas of higher susceptibility.

It is usually not cost effective to retrofit roads, or even airport runways. If a future earthquake is more centrally located in the urban portion of the Bay Area, many more road closures and airport problems are expected than occurred as a result of the Loma Prieta earthquake. For example, while 17 of the 142 street and highway closures in the Loma Prieta earthquake, and 10 of the 140 closures in the Northridge earthquake were due to liquefaction, over 40 of the over 1600 closures in a Hayward fault Annex D--All Hazard Vulnerability Assessment Updated 9/26/2005 PAGE 25 CITY OF PLEASANTON ALL-HAZARD VULNERABILITY ANALYSIS earthquake may be due to liquefaction (Perkins and others, 1997 and Perkins and others, 1998). While 10+ miles of state highway had to be resurfaced after Loma Prieta due to liquefaction, we expect many more miles will need to be repaired after a Hayward fault event. Of more significance, all three commercial airports may be partially closed. The potential problem with the Oakland and San Francisco International Airports is liquefiable fill on Bay Mud. The potential problem with the San Jose International Airport is that the runways cross a series of ancient stream channels.

Road Closures Predictions

These estimates include:

• Direct causes of closures, including faulting, liquefaction, land sliding, and shaking damage to bridges and highway interchanges; and

• Indirect causes of closures, including threat of building collapse or structural damage to highway and rail structures, small hazmat releases, water and gas pipeline leaks, and other miscellaneous closures.

Note that this modeling process does not include:

• Secondary disasters (such as huge fires, toxic gas releases far larger than occurred Northridge or Loma Prieta, or dam collapse);

• Possible road closures created for emergency housing or public assistance centers; or

• Extensive land sliding due to soils being saturated with water associated with a very large winter storm.

On the following maps, the values are aggregated from modeling performed on individual census tracts. As with most types of statistics-based modeling, total values are more accurate than values for specific counties or hazards.

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This scenario earthquake is for a magnitude 6.9 earthquake on the entire length of the Hayward fault from San Pablo Bay to the border of Alameda and Santa Clara counties.

Distribution of Closures

An earthquake along the entire Hayward fault would cause approximately 1,734 road closures and would have the most devastating effect of any of the scenarios modeled by ABAG. Almost two thirds of the expected closures (62%) are expected to occur within Alameda County alone. Contra Costa and San Francisco counties are expected to be the next most severely affected areas. In combination, these two counties are expected to account for over one quarter (28%) of the total closures.

The direct hazard of faulting in Alameda and Contra Costa counties accounts for 30% of the closures. Thus, all routes from the western portion of these counties to the I-680 corridor will be blocked. Closures within urbanized San Francisco and Alameda counties can be attributed to their older and denser urban pattern.

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The table below shows the number of roads that are predicted to be closed in Alameda County in the event of a Magnitude 6.9 earthquake along the Hayward Fault.

Ground Shaking 170 Faulting 404 Liquefaction 47 Water Pipelines 31 Gas Pipelines 6 Landslides 42 Building Damage 124 Hazmat Incident 10 Structural Damage 78 Miscellaneous 169 TOTAL 1,081 ABAG

Concentrations of Closures and Planning Implications

As can be seen from examining the above map and table, most of the closures are expected to occur along the western portion of the east Bay. The zones that are expected to have the most severe disruptions are located adjacent to the fault along the Highway 580 and 238 corridors, and along segments of the 880 corridor. While these north-south connectors may not be fully operational, there should be available alternatives through the local street network.

While it has not been within the scope of this project to predict the performance of individual structures or facilities, the effect on the Bay Area's toll bridges is expected to be serious. In addition, the devastating effect to the transportation system in and around critical transportation facilities such as the Oakland International Airport should be considered for post disaster planning.

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Specific Planning Considerations -- Hayward Earthquake - Entire Length

Roads • Highways 13 and I-580, which run parallel to the fault source and even cross the fault, will be affected by this earthquake. I-80 also crosses the fault source near San Pablo north of the I-580 junction. Many highways and roads near the fault source are also susceptible to land-sliding. • Roads in the I-880 and I-80 corridors will experience road closures due to shaking, liquefaction and building damage. • BART will probably be unable to pick up extra service due to extensive damage to the supports for its elevated sections, and may even contribute to blocking of roadways and highways. • Roads and highways in the Highway 101 corridor, particularly near the Richmond-San Rafael Bridge and State Route 37, as well as in San Francisco, are expected to experience multiple closures. • Emergency planners should consider pre-designating alternative north-south emergency arterials between the heavily impacted Bay shoreline and the fault source.

Bridges • From an emergency planning perspective, this earthquake is particularly problematic because all of the Bay Area's toll bridges may be affected, either directly or due to closures of local roads feeding the bridges. The Richmond-San Rafael, Dunbarton, Golden Gate and Bay bridges are particularly vulnerable to problems in this earthquake. Even if these bridges remain intact, liquefaction and extensive settlement on the approaches may impact traffic flow. • In addition, non-retrofitted bridges on local roads should be considered a weak link along transportation routes.

Airports • The Oakland and San Francisco International Airports are expected to be affected by multiple road closures servicing their facilities. • The San Jose International Airport, Hayward Airport, and Moffett Field, while not experiencing quite as many closures as Oakland, will probably still be affected by several closures. • Travis Air Force Base would be the closest airfield capable of handling large commercial and cargo jets should all of the above airports be inaccessible. Therefore, this airport should plan for increased air and vehicle traffic, both immediately and long term.

ABAG

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This scenario earthquake is for a magnitude 6.7 earthquake on the thrust fault under Mt. Diablo.

Distribution of Closures

An earthquake along the Mt. Diablo fault would cause approximately 228 road closures. Approximately three-fourths of these closures are expected to occur within Alameda and Contra Costa counties.

Because this fault is deep under Mt. Diablo, no road closures due to surface faulting are expected. The direct hazard of shaking damage to road and highway bridges and over-crossings, as well as building damage, are expected to account for over two fifths (43%) of the total closures.

The table below shows the number of roads that are predicted to be closed in Alameda County in the event of a Magnitude 6.7 earthquake along the Mount Diablo Thrust Fault.

Ground Shaking 32 Faulting 0 Liquefaction 8 Water Pipelines 4 Gas Pipelines 1 Landslides 9 Building Damage 9 Hazmat Incident 1 Structural Damage 15 Miscellaneous 15 TOTAL 94 ABAG

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Concentrations of Closures and Planning Implications

As can be seen from examining the above map and table, many of the closures are expected to occur along portions of central Alameda and Contra Costa counties. Transportation disruptions are expected along portions of the I-680 corridor as well in Oakland and San Francisco.

While portions of this area represent large census tracts due to its rural nature, the roads connecting the small communities are few. In most cases, these roads are not redundant and access to some of the rural communities along them might be severely impaired.

Specific Planning Considerations -- Mt. Diablo Earthquake

Roads • The I-680 corridor is expected to experience multiple road closures as a result of this scenario earthquake. These closures are of particular concern due to the lack of alternative arterials and its major role in freight movement.

Bridges • Approaches to the Richmond-San Rafael, Benicia, and Bay bridges may be affected by road closures as a result of this earthquake. • In addition, non-retrofitted bridges on local roads should be considered a weak link along transportation routes.

Airports • It is unlikely that any major commercial airports will be affected by significant road closures as a result of this scenario earthquake. However, access to Buchanan Airport may be impacted.

ABAG

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This scenario earthquake is for a magnitude 6.9 earthquake on the Greenville fault in far eastern Contra Costa, Alameda and Santa Clara counties. This fault was the source of the Livermore Earthquake, which occurred on January 24, 1980 at a11 AM and registered Magnitude 5.8 Richter.

Distribution of Closures

An earthquake along the Greenville fault would cause approximately 138 road closures. This significant reduction from the 193 road closures estimated for an earthquake on this fault in 2002 is due to a significant reduction in the estimated fault length by the U.S. Geological Survey. Over four-fifths (85%) of these closures are expected to occur within Alameda and Contra Costa counties.

The direct hazards of fault rupture, shaking damage to road and highway bridges and over-crossings, and land-sliding are expected to account for approximately half of the total closures.

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The table below shows the number of roads that are predicted to be closed in Alameda County in the event of a Magnitude 6.9 earthquake along the Greenville Fault.

Ground Shaking 15 Faulting 20 Liquefaction 3 Water Pipelines 4 Gas Pipelines 1 Landslides 6 Building Damage 3 Hazmat Incident 1 Structural Damage 7 Miscellaneous 11 TOTAL 70 ABAG

Concentrations of Closures and Planning Implications

As can be seen from examining the above map and table, most of the closures are expected to occur along portions of eastern Alameda and Contra Costa counties. Transportation disruptions are expected along portions of the I-580 corridor as well as along rural sections of State Route 84. Areas within and around Pleasanton are expected to experience the largest concentrations of closures.

While this area presents large census tracts due to its rural nature, the roads connecting the small communities are few. In most cases, these roads are not redundant and access to some of the rural communities along them might be severely impaired.

Specific Planning Considerations -- Greenville Earthquake

Roads • The I-580 corridor is expected to experience multiple road closures as a result of this scenario earthquake, particularly of those routes crossing the fault source area west of Altamont Pass. These closures are of particular concern due to the lack of alternative arterials and its major role in freight and commuter movement.

Bridges • It is unlikely that any of the toll bridges will be affected by road closures as a result of this earthquake. • However, non-retrofitted bridges on local roads should be considered a weak link along transportation routes.

Airports It is unlikely that any commercial airports will be affected by significant road closures as a result of this scenario earthquake. However, we anticipate that the Livermore Airport will be impacted by road closures.

ABAG

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This scenario earthquake is for a magnitude 6.7 earthquake on the Concord - Green Valley fault in Contra Costa and Solano counties.

Distribution of Closures

An earthquake along the Concord-Green Valley fault would cause approximately 386 road closures. Although not as many closures are expected as in some of the other scenarios, this number is still 2.7 times as many as in either the Northridge or Loma Prieta earthquake. Over half of the expected closures (52%) are expected to occur within Contra Costa County alone. Other than an earthquake along one or more segments of the Hayward fault, this earthquake is expected to generate the greatest number of closures within Contra Costa County.

The direct hazards of fault rupture and shaking damage to road and highway bridges and over- crossings account for almost one half (49%) of the closures within Contra Costa County.

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The table below shows the number of roads that are predicted to be closed in Alameda County in the event of a Magnitude 6.7 earthquake along the Concord-Green Valley Fault.

Ground Shaking 18 Faulting 0 Liquefaction 6 Water Pipelines 3 Gas Pipelines 1 Landslides 5 Building Damage 6 Hazmat Incident 0 Structural Damage 8 Miscellaneous 9 TOTAL 56 ABAG

Concentrations of Closures and Planning Implications

As can be seen from examining the above map and table, there is a significant concentration of closures along segments of the I-680 corridor in Solano and Contra Costa counties. Areas within and around the cities of Benicia, Vallejo (Cordelia) and Martinez are expected to have significant disruptions within them and between them.

At the same time, while significant disruptions are expected on both sides of the Carquinez Strait, any potential effect on the connecting Benicia-Martinez toll bridge is particularly critical since this bridge is not redundant.

Finally, portions of eastern Solano and Contra Costa Counties may experience serious access problems.

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Specific Planning Considerations -- Concord-Green Valley Earthquake

Roads • The I-680 corridor is the key north-south route in the impacted area. Multiple closures are expected along this corridor.

• BART may be unable to pick up extra service in the I-680 corridor due to extensive damage to the supports for its older elevated sections, and may even contribute to blocking of roadways and highways.

• Parts of the State Route 24 corridor, particularly that portion near the I-680 interchange, are expected to experience multiple road closures. Although the length of the affected roadway is only several miles, State Route 24 is a major east-west route in the Bay Area.

• Emergency response planners should also anticipate that State Routes 4, 121, and 242 transportation corridors (including both the highways themselves and the local streets along these routes) will be affected by multiple closures.

Bridges • The Carquinez and Benicia-Martinez Bridges are the most direct links between the heavily impacted areas in the North and East Bay. For planning purposes, it should be assumed that these bridges may be closed, at least for a few days. Emergency planners should expect that approaches to these bridges, as well as local roads feeding the bridges, will be affected by multiple road closures on at least one of their ends. • Liquefaction and other hazards may affect the approaches, as well as feeder roads, to the other toll bridges in the region. • In addition, non-retrofitted bridges on local roads should be considered a weak link along transportation routes.

Airports • Emergency response planners should assume that Oakland International Airport, Buchanan Field in Concord, and Napa County Airport will be affected by multiple closures of roads servicing their facilities after this scenario earthquake. • Alternative air facilities at San Jose or San Francisco International Airports and Travis AFB are expected to be more accessible. Therefore, these airports should plan for increased air and vehicle traffic, both immediately and long term, should other airports have access difficulties.

ABAG

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This scenario earthquake is for a magnitude 6.2 earthquake on the central segment of the Calaveras fault, extending from Calaveras Reservoir in northern Santa Clara County to San Benito County.

Distribution of Closures

An earthquake along the Central Calaveras fault would cause approximately 210 road closures. Almost two thirds of the closures are expected to occur within Santa Clara County alone. Although the impacts in that county are not as significant as for an earthquake on the San Andreas or the Monte Vista faults, they are still significant. The total number of closures in Santa Clara County alone exceeds that experienced region-wide in either the Loma Prieta or Northridge earthquakes. Alameda County is expected to be the next most severely affected county, with almost one fourth (24%) of the total closures.

The direct hazard of shaking damage to bridges and over-crossings on roads and highways is expected to be a significant source of closures; it is expected to account for almost one fourth (22%) of the total closures.

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The table below shows the number of roads that are predicted to be closed in Alameda County in the event of a Magnitude 6.2 earthquake along the Central Calaveras Fault.

Ground Shaking 17 Faulting 0 Liquefaction 4 Water Pipelines 2 Gas Pipelines 0 Landslides 5 Building Damage 4 Hazmat Incident 1 Structural Damage 8 Miscellaneous 8 TOTAL 51 ABAG

Concentrations of Closures and Planning Implications

As can be seen from examining the above map and table, most of the closures are expected to occur along portions of eastern Santa Clara and Alameda counties. Transportation disruptions are expected along portions of the State Route 101 and 152 corridors. Areas within and around the communities of Gilroy, Morgan Hill, and southern San Jose are expected to experience the largest concentrations of closures.

Specific Planning Considerations -- Central Calaveras Earthquake

Roads • The State Route 101 corridor is the key route in the impacted area. Multiple closures are expected along this corridor.

• Emergency response planners should also anticipate that the State Route 152 transportation corridor over Pacheco Pass will be affected by multiple closures.

Bridges • It is unlikely that any of the toll bridges will be affected by significant road closures as a result of this earthquake.

Airports • Emergency response planners should assume that San Jose International Airport may be affected by closures of roads servicing its facility after this scenario earthquake. • Alternative air facilities at Oakland and San Francisco International Airports and Travis AFB may be more accessible. Therefore, these airports should plan for increased air and vehicle traffic, both immediately and long term, should the San Jose Airport continue to experience access difficulties.

ABAG

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This scenario earthquake is for a magnitude 7.1 earthquake on combined northern segment of the Hayward fault and the Healdsburg-Rodgers Creek fault between Healdsburg and Oakland.

Distribution of Closures

An earthquake along the combined Northern Hayward - Rodgers Creek faults would cause approximately 1,084 road closures.

Most of the road closures in this scenario are expected to occur in Alameda County (33%), Contra Costa County (24%), and Sonoma County (21%).

Fault rupture is expected to be one of the most significant causes of road closures, accounting for 24% of the closures. Closures due to building damage, which accounts for 19% of the closures, are expected to be significant in the more urban counties of Alameda and San Francisco.

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The table below shows the number of roads that are predicted to be closed in Alameda County in the event of a Magnitude 7.1 earthquake along the Rodgers Creek-North Hayward Fault.

Ground Shaking 91 Faulting 61 Liquefaction 12 Water Pipelines 12 Gas Pipelines 2 Landslides 20 Building Damage 64 Hazmat Incident 4 Structural Damage 42 Miscellaneous 57 TOTAL 363 ABAG

Concentrations of Closures and Planning Implications

As can be seen from examining the above map and table, most of the closures are expected to occur along the east Bay and north into Sonoma County. Three zones are expected to have the most severe transportation disruptions: the zone immediately adjacent to the fault along the I-580 corridor; the zone immediately adjacent to the Bay along the I-880 corridor; and the zone along the State Route 101 corridor in Sonoma County. Few alternatives are available if these north-south connectors are not fully operational in the North Bay. available through the local street network.

While it has not been within the scope of this project to predict the performance of individual structures, the effect on the Bay Area's toll bridges is expected to be serious, particularly the Richmond, Carquinez, and Bay bridges. It should also be noted that in most cases these bridges are not redundant and that thinking about alternatives in the event that they are not fully functional is critical.

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Specific Planning Considerations -- Rodgers Creek - Northern Hayward Earthquake

Roads • All roads crossing faults will probably close. For example, Highways 13 and I-580, which run parallel to the fault source and even cross the fault, will be affected by this earthquake. I-80 crosses the fault source near San Pablo north of the I-580 junction, while Highway 24 crosses it near the Caldecott Tunnel. Many highways and roads near the fault are also vulnerable to land sliding, causing additional closures. • Roads in the I-880 and I-80 corridors will experience road closures due to shaking, liquefaction and building damage. • BART will probably be unable to pick up extra service due to extensive damage to the supports for its elevated sections, and may even contribute to blocking of roadways and highways. • Local roads and highways in the Highway 101 corridor, particularly near I-580, the Richmond-San Rafael Bridge, State Route 37, and in San Francisco, are also expected to experience multiple road closures. • Emergency planners should consider pre-designating alternative north-south emergency arterials between the heavily impacted East Bay shoreline and the fault source.

Bridges • From an emergency planning perspective, this scenario earthquake is particularly problematic because all of the Bay Area's toll bridges may be affected, either directly or due to closures of local roads feeding the bridges. The Richmond-San Rafael, Carquinez, and Bay bridges are particularly subject to problems in this earthquake. Even if these bridges remain intact, liquefaction and extensive settlement on the approaches may impact traffic flow. • In addition, non-retrofitted bridges on local roads should be considered a weak link along transportation routes. These problems will be particularly severe in the North Bay, where few alternatives exist.

Airports • The Oakland International Airport and Santa Rosa Airport are expected to be affected by multiple road closures servicing their facilities. • The San Francisco and San Jose International Airports, as well as Moffett Field, Travis AFB, and other smaller airports such as Buchanan, San Carlos and Hayward, may be more accessible than Oakland. Therefore, these airports should plan for increased air and vehicle traffic, both immediately and long term, following this earthquake. .

ABAG

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Hazardous Materials Problems in Earthquakes

A hazardous material is a substance or combination of substances which, because of quantity, concentration, physical, chemical or infectious characteristics may either:

• Cause, or significantly contribute to an increase in deaths or serious illness; or

• Pose a substantial present or potential hazard to humans or the environment.

• More specifically, hazardous materials have one or more of the following properties:

o flammable;

o corrosive or irritant;

o oxidizing;

o explosive;

o radioactive;

o infectious;

o thermally unstable or reactive; or

o poisonous (including carcinogens, mutagens, and teratogens).

While hazardous materials are commonly associated with manufacturing and industrial areas, they are also associated with retail and commercial businesses.

• Gas stations have gasoline, oils, and cleaning solvents.

• Retail stores sell automotive products, pesticides, cleaning supplies, paints, and swimming pool chemicals.

• Warehouses and transfer facilities may temporarily or commonly handle hazardous materials.

• Plating, printing shops, dry cleaners all have specialty chemicals necessary for their operations.

• Grocery stores have refrigeration facilities that may contain hazardous materials.

• Even something as innocuous as a florist has helium to fill balloons.

Earthquakes have a number of different effects.

Almost all hazardous materials incidents result from ground shaking. One depiction of the ground shaking hazard are ground shaking hazard maps. However, the number and severity of hazardous materials incidents depends not only on the severity of shaking, but also on the design of facilities. For example, un-reinforced masonry and poorly engineered tilt-up concrete and concrete frame buildings can be quite susceptible to catastrophic structural damage. In addition, the shaking damage to contents increases higher up in buildings, particularly in flexible steel-frame buildings.

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Fault rupture, or surface rupture, commonly occurs during earthquakes in California because the earthquakes originate relatively near the earth's surface. The ground surface ruptures, or breaks, as the ground on one side moves relative to the ground on the other side. The displacement can be vertical, horizontal, or a combination of both and may be only a few inches or several feet. Any buildings or pipelines built across the fault trace will almost certainly be deformed or destroyed. While California's Alquist-Priolo Fault Special Studies Zones Act prevents buildings for human occupancy from being constructed across an active fault, buildings built prior to the Act's passage in the early 1970s, as well as pipelines, rail lines, or roads, are exempt. These infrastructure lifelines must cross faults in California or our principal urban areas would not function.

Liquefaction is a process in which loose water-saturated sands and other granular materials suddenly lose strength when shaken. The lurching and sliding that occurs can cause severe damage to structures built upon, or pipelines constructed within, those deposits. This problem occurred in the Lake Merced area during the Daly City earthquake of 1957, as well as the Oakland approach to the Bay Bridge and the Marina District of San Francisco during the Loma Prieta earthquake of 1989.

Earthquake-triggered landslides can occur in hillside areas. Because few businesses are located in these areas, the principal impact of these slides will be on roads and pipelines.

Tsunamis (great waves often called "tidal" waves that originate in the ocean and have nothing to do with the tides) and seiches (waves that originate in closed or semi-closed bodies of water such as reservoirs) are a potential threat to low-lying waterfront areas, particularly facing the Pacific Ocean rather than in San Francisco Bay.

The types of failures which cause hazardous materials releases during earthquakes include:

1. Building structural failures.

2. Dislodging of asbestos or encapsulated asbestos.

3. Underground pipeline breaks due to soil movement.

4. Above-ground pipeline breaks due to:

a. Breaks in short connector pipes due to differential movement between pipes and structures.

b. Impact from other structures or equipment.

c. Damage from failing pipe supports.

5. Cylindrical storage tank failures due to "elephant's foot" buckling, weakening from corrosion, or sloshing of contents.

6. Toppling of elevated tanks.

7. Shifting and overturning of horizontal tanks;

8. Sloshing from open-topped tanks.

9. Industrial equipment problems due to sliding or overturning, or internal failures.

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10. Falling containers and shelves, particularly in:

a. Hospital, school or business laboratories; or

b. Liquor, drug or grocery stores.

Other factors that can complicate the ability to respond to these releases, include:

1. Breakdowns in utilities, including communications, water, and power.

2. People not following established procedures or not using restraining devices.

3. Malfunctions of control or alarm systems.

4. Shortages of emergency and clean-up personnel.

5. Disruptions of transportation supply/distribution systems.

6. Indirect impacts due to damage to raw material suppliers or equipment suppliers.

City government has different roles related to hazardous materials problems in earthquakes. First, the City owns and operates facilities that use and store hazardous materials. Next, it can encourage private businesses to take a more active role in mitigating potential releases in an earthquake. Finally, it responds to hazardous materials emergencies during earthquakes.

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Flood

Floods are the most common and widespread of all natural disasters— except fire. Most communities in the United States can experience some kind of flooding after spring rains, heavy thunderstorms, or winter snow thaws. Floods can be slow, or fast rising but generally develop over a period of days.

Dam failures are potentially the worst flood events. A dam failure is usually the result of neglect, poor design, or structural damage caused by a major event such as an earthquake. When a dam fails, a gigantic quantity of water is suddenly let loose downstream, destroying anything in its path.

Flash floods usually result from intense storms dropping large amounts of rain within a brief period. Flash floods occur with little or no warning and can reach full peak in only a few minutes.

1. Flood waters can be extremely dangerous. The force of six inches of swiftly moving water can knock people off their feet. The best protection during a flood is to leave the area and go to shelter on higher ground.

2. Flash flood waters move at very fast speeds and can roll boulders, tear out trees, destroy buildings, and obliterate bridges. Walls of water can reach heights of 10 to 20 feet and generally are accompanied by a deadly cargo of debris. The best response to any signs of flash flooding is to move immediately and quickly to higher ground.

3. Cars can easily be swept away in just 2 feet of moving water. If flood waters rise around a car, it should be abandoned. Passengers should climb immediately to higher ground.

Substantial areas within central Alameda County are subject to flooding. According to FEMA records, the majority of the County's creeks and shoreline areas lie within the 100-year flood plain (an area subject to flooding in a storm that is likely to occur according to averages based upon recorded measurements once every 100 years). The FEMA records are maintained as a means of determining flood insurance rates through the National Flood Insurance Program.

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Significant Flood Events

A significant event is one with 1,500 or more paid losses, or occasionally one added for other reasons. Following are significant flood events that have affected Northern California:

Flood Event Name (FEMA data) Date # of paid losses Total Losses Average Loss

California Flood February 1986 Feb-86 1,865 $33,244,108 $17,825

N. California Flood Jan-95 595 $8,301,151 $13,952

California Flood December 1996 Dec-96 1,831 $39,433,756 $21,537

California Flood – Northern Jan-98 2,073 $33,117,214 $15,976

Flood Loss Estimation

HAZUS Loss Estimation Models: Flood

The flood loss estimation methodology consists of two basic analytical processes: flood hazard analysis and flood loss estimation analysis. In the hazard analysis module, characteristics such as frequency, discharge, and ground elevation are used to estimate flood depth, flood elevation, and velocity. In the loss estimation module, physical damage and economic loss is calculated based on the results of the hazard analysis. The results are displayed using a series of reports and maps.

Users may perform three levels of analysis using HAZUS Flood. The following describe the information and expertise needed for each level:

Level 1

All of the information needed to produce a basic estimate of local flood losses will be included as default data, based on national databases and nationally applicable methods.

Level 2

More accurate estimates will be needed including detailed information on local conditions. Modification of default databases will be required, along with the inclusion of local data and analyses.

Level 3

Detailed and site-specific input data will be used to create state-of-the-art damage estimates and situation assessment profiles. Level 3 is intended for the expert user.

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Local Flood Information

To ensure controlled drainage of the Valley's surface water runoff, Zone 7 manages a watershed of nearly 620 square miles of eastern Alameda County, and parts of Contra Costa, Santa Clara and San Joaquin counties. Water travels though a number of tributaries, which drain through the larger Arroyo de la Laguna and Alameda Creek into the San Francisco Bay.

More than 37 miles of flood control channels and drainage facilities are owned and maintained by Zone 7, with a comprehensive year-round program that includes repairing slides and erosion, refurbishing access roads and associated drainage ditches, installing and repairing gates and fences, and maintaining landscaped areas.

As a result of good planning and system maintenance, the Livermore-Amador Valley has experienced minimal flood damage compared with other areas of California. Storm damage over the past four years has required three major repair projects at a total cost of $2.6 million. To finance repairs associated with federally declared disasters in early 1995, Zone 7 requested funding from the Federal Emergency Management Agency (FEMA). Zone 7 has also applied for assistance from the U.S. Army Corps of Engineers for repair of future damage.

Flood History

The terrain within the corporate limits of Pleasanton is level, and drainage through the geologically recent alluvial soils is generally poor due to the existence of relatively an impermeable clay “cap” soil layer covering most of the valley. This exacerbates the flood hazard existing in Pleasanton resulting from the possibility of heavy rain causing natural flooding due to the overflow of stream courses.

Historically, the Amador Valley has experienced relatively frequent and substantial flooding because many streams which drain large areas of impermeable soils converge in the area. During periods of intense rainfall, runoff rapidly causes stream flows to exceed floodway capacities and inundate adjacent areas of the flat valley floor. Extensive flood channel improvements required of development . projects during the past fifteen years have significantly reduced this type of flood hazard.

The flood plains within the city are very broad. Historically, when severe flooding has occurred, the entire valley floor has been flooded. All construction that exists within the portions of the City of Pleasanton on the valley floor are, therefore, within potential flood hazard areas.

FEMA maintains detailed maps of all areas with flooding history to help the insurance industry determine rates. Copies of these maps are available in the Emergency Operations Center.

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s a e r on A Information from FEMA – National Flood Insurance sant a NG e/Ple r rmo FLOODI Live NTIAL AREAS OF POTE

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Principal Flood Problems

Flood-producing rainfall occurs during the winter months in the Pleasanton area. Storm runoff is concentrated rapidly by the network of tributaries through the hills which discharge into Arroyo Mocho, Arroyo Del Valle and other tributaries to the Arroyo De La Laguna. The tributaries have carved well- defined courses through the hills; but, upon reaching the flat valley, the channels become shallow and inadequate for higher frequency flows.

The main flooding problem is currently caused by the low capacity of the lower reaches of Arroyo De La Laguna, which causes backwater flooding in its tributary channels.

When substantial rainfall does occur, the runoff is rapid and heavy, causing stream-flows to exceed the normal stream courses’ capacities and inundates large areas of the flat valley floor. Flooding is not limited to occasions of intense precipitation, however. Flooding may occur following low-intensity precipitation spread over several days, as occurred in storms of 1955 and 1958.

Flood Protection Measures

Special Drainage District 7 of the Alameda County Flood Control and Water Conservation District (Zone 7), was set up to improve flood control in the valley. Streambed channelization along Arroyo De La Laguna, Alamo Canal, Arroyo Mocho, Hewlett Canal, Chabot Canal, Pleasanton Canal and Tassajara Creek has substantially reduced the possibility of extensive flooding, especially by reducing the time of ponding. A major dam on Arroyo Del Valle controls flooding on that waterway.

Flood events of a magnitude which are expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or 500-year period have been selected as having special significance for flood plain management and for flood insurance rates. These events, commonly termed the 10-, 50-, 100-, and 500-year floods have a .2% chance of being equaled or exceeded during any one year. Although the recurrence interval represents the long term average period between floods of a specific magnitude, rare floods could occur at short intervals, or even within the same year. The risk of experiencing a rare flood increase when periods of greater than 1 year are considered.

Severe Weather

El Niño

The term El Niño refers to a rapid, dramatic warming of the sea-surface temperatures in the eastern tropical Pacific, chiefly along the north-central coast of South America and westward. El Niño is a temporary change in the climate of the Pacific Ocean in the region around the equator. Strong winds blow east to west and pile up water in the western part of the Pacific causing colder water to be pulled up to fill the void in the east. This condition weakens the wind allowing the warmer water to slump back to the east. As the winds weaken and water continues to warm, the condition exacerbates. This poses a flood and storm damage threat to the west coast and the Bay Area. The primary storm forecast window is usually January through March during an El Niño year. The position of the jet stream will determine where landfall of the storms occurs.

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El Niño is NOT:

• A series of catastrophic flood producing weather events in California or the West

• A hurricane

• A period of drought in California or the West

• A series of storms

Any of these MAY occur as an impact of El Niño (or be associated with it coincidentally).

Not all flooding events in California occur during El Niño years, and not all El Niño years produce widespread flooding. For example, 1997 (a non El Niño year) saw seasonal rainfall totals near normal throughout most of California. However because most of the 1997 season's precipitation fell during December and January (instead of being spread throughout the season) there were record floods in many parts of the state. Some other historic floods in California that have occurred during non-El Niño Years include Christmas 1955, December 1964, January 1982 and February 1986.

Initial newspaper, television and radio reports (in summer 1997) on the issue of El Niño and its impact on California rainfall in many cases were misleading. For example, early (summer 1997) attempts at computer modeling of impacts of El Niño patterns on California precipitation did indeed produce a unified view that heavier than normal precipitation would occur, particularly in Southern California.

In addition, much confusion was apparent in the press on the issue of what El Niño actually was and what the impacts of El Niño would be. All of this has led to a domino effect of poorly drawn conclusions and overreactions.

However, some of the computer runs produced extreme outlier "foreshadowings" of 300-400% normal precipitation or greater. General reports in the media focused on these extreme numbers (without providing the context) and not the consensus view of meteorologists. Misinterpretations of such results of computer modeling predictions (that really applied to Southern California) then were reported widely as applying to the whole state and also attributed to meteorologists in general.

1. There is absolutely NO evidence in the record to support contentions that El Niño events can be (or ever were) associated with "300% to 400% of normal rainfall" in north-central California. 300% to 400% would produce rainfall of 60" to 80" in San Francisco. The greatest rainfall total ever recorded at San Francisco (season of 1861-62) was on the order of 49" or so, about 230% of the long term average.

2. Flooding events in California relate to timing and intensity of the rainfall systems that affect the state. It is true that storms on a greatly-strengthened subtropical storm track are more frequent in El Niño years. However, the phasing of such storms and other factors such as the saturation of the soils and tides determine whether or not flooding and mud-sliding will occur even in an El Niño year in which the yearly precipitation is substantially greater than normal

The type of situation that most often leads to flooding in California is when a succession of low latitude storms impact an already saturated region in a short period of time. The probability of this occurring is greater during El Niño events because of the shift in the storm track, but even a day or two break between weather systems can make a large difference in the flood potential.

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For the eight well-documented Type 1 winter El Niño events since 1950 (rainfall seasons of 1951-52, 1957-58, 1965-66, 1968-69, 1972-73, 1977-78, 1982-83 and 1991-92), rainfall at San Francisco averaged about 37% greater than normal, with a mean anomaly of about 7.5 inches at San Francisco (thus, implying an average rainfall for Type 1 El Niño events of around 28.5" compared to the 30 year average of 21" or so). Note also that several Type 1 seasons were very wet (>170%), suggesting that there should be a reasonable concern for such amounts in the winter of 1997-98.

Meteorological reports forecast potentially frequent storms and heavy rain from El Niño. The Alameda County Flood Control District, Livermore Department of Services and Pleasanton Department of Public Works participated in the October 14, 1997 El Niño Community Preparedness Summit hosted by the Federal Emergency Management along with key staff from other jurisdictions from around the state.

Agencies operate under the premise that a catastrophic weather front could impact Alameda County and the Livermore/Pleasanton areas at any time, and, therefore, consistently maintain elevated standards of preparation. Jurisdictions should minimize the danger of flood throughout the area by the consistent, vigilant monitoring and maintenance of critical parts of the flood control system. Also, it is vital to ensure that water passage ways, channels and pipelines are free of debris, silt and vegetation.

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Wild Land Fire

Wildfire is a critical part of California’s ecosystem, both as a result of natural phenomena, such as climate, vegetation, and lightning, and as a result of human activities. Every year these factors combine into a set of potential burning conditions that raise the question not of whether it will burn but of when it will burn.

During late October and early November of 1993, the citizens of California were shown what can happen when weather and fuel conditions are right for wildfire. Last fall’s Southern California fires resulted in the loss of 4 lives and the destruction of over 1,500 structures. The Oakland Hills Fire, which occurred under similar conditions in fall of 1991, resulted in the loss of 26 lives and the destruction of over 2,500 homes. Since 1990 alone, California has lost over 4,500 homes and 30 lives to catastrophic wildfire. A general trend we are seeing in our wildfire seasons is that the number of acres that burns is remaining about the same while the number of structures destroyed is increasing. In addition to these impacts of loss of life and property, there are also the impacts of soil erosion, water quality degradation, forest and rangeland vegetation destruction, loss of wildlife habitat, and damage to infrastructure such as power lines.

When the hazards of structures, fire prone fuels, steep topography and fire weather are intermixed with the risk associated with people, often with no clearly defined boundary or interface, the possibility of mutual destruction by wildfire greatly increases. The structures themselves are highly vulnerable to wildfire, historically being built with little concern for resisting ignition. Survivability and self-protection were not considered; reliance on fire department response was their protection. It is important to keep in mind, in the populated portions of California, 90 percent or more of the fires involving vegetation are caused either by people directly or by their activities [e.g., arson, settlements, recreational pursuits, various types of machine uses, power lines, and railroads].

Pleasanton experiences long, dry summers with high wild land fire hazards. The risk of wildfire hazard is related to a combination of factors including winds, temperatures, humidity levels, and fuel moisture content. Of these four factors, wind is the most critical. Steep slopes also contribute to fire hazard by intensifying the effects of wind, and making fire suppression difficult. Features in parts of the area are highly flammable vegetation, warm and dry summers, rugged topography and occasional human presence. This creates a situation that results in potential wild land fires.

Fire hazards present a considerable problem to vegetation and wildlife habitats throughout the area. Grassland fires are easily ignited, particularly in dry seasons. These fires are relatively easy to control if they can be reached by fire equipment. The burned slopes, however, are highly subject to erosion. While brush lands are naturally adapted to frequent light fires, fire protection and prevention measures, in recent decades, has resulted in heavy fuel accumulation on the ground.

Vegetation fires, particularly near the end of the dry season, tend to burn fast and very hot, threatening homes in the area and leading to serious destruction of vegetation cover. While woodland fires are relatively cool under natural conditions, a vegetation fire that spreads to woodland could generate a destructive hot crown fire. No suitable management technique of moderate cost has been devised to reduce the risk of vegetation fires.

The Livermore-Pleasanton Fire Department maintains standard operating procedures for responding to wild land fires. Because of the developed area around Livermore and Pleasanton, fires of this nature should not pose a threat to the extent of becoming a disaster; however, their occurrence during a disaster response most certainly would exacerbate matters.

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To quantify this potential risk, the California Department of Forestry (CDF) has developed a Fire Hazard Severity Scale which utilizes three criteria in order to evaluate and designate potential fire hazards in wild land areas. The criteria are fuel loading (vegetation), fire weather (winds, temperatures, humidity levels and fuel moisture contents) and topography (degree of slope). According to CDF maps, wild land fire hazard is moderate throughout the Pleasanton Area.

Livermore/Pleasanton Area

California Department of Forestry

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Land slides

A landslide is the movement of rock and soil that may take place gradually over a small area, or it may be very rapid and involve an huge area. Landslides may also be initiated by removal, or absence, of soil-retaining vegetation, from causes such as wild land fires or changes in agricultural practices. Removal of material at the base of slopes may result in unstable conditions. Heavy building structures, mine dumps and road fill may add enough stress to initiate landslide movement in otherwise stable conditions.

Water and wind carry soil from our Bay Area land down into our streams, lakes, and the Bay. This soil carries with it pollutants such as oil and grease, chemicals, fertilizers, animal wastes and bacteria, which threaten our water quality.

Nature slowly wears away land, but human activities such as construction increase the rate of erosion 200, even 2,000 times that amount. When we remove vegetation or other objects that hold soil in place, we expose it to the action of wind and water and increase its chances of eroding.

The loss of soil from a construction site results in loss of topsoil, minerals and nutrients, and it causes ugly cuts and gullies in the landscape. Surface runoff and the materials it carries with it clog our culverts, flood channels and streams. Sometimes it destroys wildlife and damages recreational areas such as lakes and reservoirs.

Bare Slopes vs. Vegetatively Stabilized Slopes (USGS)

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Such erosion costs the home construction industry, local governments, and homeowners of the Bay Area millions of dollars a year. Damage to roads and property is costly and tax dollars have to be spent on cleaning out sediment from storm drains, channels, lakes, and the Bay. As an example, road and home building in the Oakland hills above Lake Temescal filled the lake to such an extent that it had to be dredged in 1979 at a public cost of $750,000.

Total direct costs of damage from landslides (including debris flows)

Transportation $21,322,000

Utilities $3,202,000

Parks $3,714,000

Private Property and other businesses $37,352,000

Miscellaneous $660,000

Total (1982 $$) $66,250,000

U. S. Geological Survey

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Hazards From "Mudslides", Debris Flows

More than 100 Californians have been killed by debris flows during the past 25 years. Most of these 100 deaths occurred when debris flows buried persons who were sleeping in lower-floor bedrooms that were adjacent to hazardous slopes.

Sudden "mudslides" gushing down rain-sodden slopes and gullies are widely recognized by geologists as a hazard to human life and property. Most "mudslides" are localized in small gullies, threatening only those buildings in their direct path. They can burst out of the soil on almost any rain-saturated hill when rainfall is heavy enough. Often they occur without warning in localities where they have never been seen before.

The ashy slopes left denuded by wildfires in California are especially susceptible to "mudslides" during and immediately after major rainstorms. Those who live down-slope of a wildfire area should be aware of this potential for slope failure that is present until new vegetation rebinds the soil.

Debris Flows

Debris flows (popularly called "mudslides") are shallow landslides, saturated with water, that travel rapidly down-slope as muddy slurries. The flowing mud carries rocks, bushes, and other debris as it pours down the slopes.

A debris avalanche (Figure 1) is a fast-moving debris flow that travels faster than about 10 mph or approximately 25 yards in about 5 seconds. Speeds in excess of 20 mph are not uncommon, and speeds in excess of 100 mph, although rare, do occur locally.

Sketch of a typical debris avalanche scar and track. Although this figure shows the "zone of deposition" as quite near the source, debris avalanches can travel thousands of feet or, in exceptional cases, miles from the point of origin.

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Debris avalanches pose hazards that are often overlooked. Houses in the path of debris avalanches can be severely damaged or demolished. Persons in these structures can be severely injured or killed.

Most rainstorms are of such low intensity that they do not trigger debris avalanches. Some intense storms may trigger only a few debris avalanches. However, when the ground is already saturated from previous rain, even relatively short high-intensity rainstorms may trigger debris avalanches. For example, in January 1982, an intense rainstorm triggered literally tens of thousands of debris avalanches in the San Francisco Bay Area. These 1982 debris avalanches caught people unaware and caused 14 deaths and many injuries and destroyed or damaged several hundred homes and other structures.

The most common cause of debris avalanches and debris flows is the combination of heavy rainfall, steep slopes, and loose soil. Most fairly steep slopes have enough soil and loose rock for potential landslides. Although "stable" when dry, such slopes can produce local debris flows, often without warning.

Normally the source of the excess water is intense rainfall, although broken water pipes or misdirected runoff concentrated by roads, roofs, or large paved areas may trigger, or help to trigger, debris avalanches and debris flows. In California, most debris flows occur during wet winters.

Debris avalanches occur all over the world. They are particularly common in mountainous areas underlain by rocks that produce sandy soils. Debris avalanches have been noted in southern California during at least nine rainy seasons since 1915. They have occurred in northern California during at least 14 rainy seasons since 1905.

Debris flows are known to start on slopes as low as 15 degrees, but the more dangerous, faster moving flows (debris avalanches) are more likely to develop on steeper slopes. About two-thirds of all debris avalanches start in hollows or troughs at the heads of small drainage courses. Typically, a debris avalanche bursts out of a hillside and flows quickly down-slope, inundating anything in its path. Because the path of a debris flow is controlled by the local topography just like flowing water, debris avalanches and debris flows generally follow stream courses.

Slopes burned by wild fires are especially susceptible to debris avalanches and debris flows because of the absence of vegetation and roots to bind the soil. The areas directly down-slope are especially subject to damage from debris flows.

The hazard from debris flows that occurs in modified slope cuts can be decreased by

1. Limiting the height and slope of cuts and fills,

2. Properly compacting fills and keying them into bedrock, and

3. Properly controlling the flow of water onto slopes. If steep cuts or fills occur below the discharge points of runoff water from streets, downspouts, or similar drainage facilities onto a slope, it may be wise to obtain advice from an engineering geologist or erosion control specialist.

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Rock Slides

Rock slides occur where sedimentary rocks are capped by tertiary lava flows. When the sedimentary rock weathers and erodes it undermines the lava cap and a rock fall results.

Local Slide Potential

A high potential for active land sliding should be considered to exist on all slopes bordering the Amador Valley and other hill slopes within the corporate limits, unless site specific geotechnicaI investigations can demonstrate local stability. However, the Southeast Hills are generally more stable and less prone to slope failure than the eastern slopes of the Pleasanton Ridge.

Development is restricted in areas prone to landslides, slope instability, or with slopes of 25 percent grade or greater. In unstable areas, the City seeks to minimize grading of slopes for construction or slope stability repairs, limit grading only to where it is essential for development, and prohibit major grading where existing slopes are 25 percent or greater.

The potential for land sliding is addressed by designating a majority of the land on Pleasanton Ridge as Agricultural & Grazing and Parks & Recreation, and the Southeast Hills as Public Health and Safety. Flatter and generally more stable portions of these areas are designated for low density residential development surrounded by rural density residential development because the potential for landslides and other hazards appears to be sufficiently low in these areas.

Expansive Soils are surface deposits rich in clays that expand when wet and shrink when dried. While this geologic hazard does not produce the catastrophic impacts of a large earthquake, their cumulative economic cost to a community can be considerable. Shrinks-well activity in subsurface soils can seriously damage building foundations, streets and other paved areas, underground utilities, and swimming pools. When expansive soils are present on a slope, they can promote down-slope creep of the entire thickness of surficial deposits present on the slope (in some cases to depths of more than ten feet). Expansive soils are potentially present at or near the surface in areas in northern Pleasanton and along the northeastern flank of Pleasanton Ridge. A moderate potential exists for their presence most everywhere else where terrain slopes.

Requirements have become more stringent since the 1970’s and early 1980’s when a number of Pleasanton‘s residences were constructed and have since suffered some structural and foundation damage due to expansive soils.

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Man-Caused Hazards

Dam Failure Inundation

Dam failures can result in the worst flood events. A dam failure is usually the result of neglect, poor design, or structural damage caused by a major event such as an earthquake. When a dam fails, a gigantic quantity of water is suddenly let loose downstream, destroying anything in its path. For example, in 1889, more than 2,200 lives were lost as a result of the Johnstown, Pennsylvania flood caused by an upstream dam failure. Billions of dollars of property damage can also occur as a result of a dam failure.

More recently, in 1971, during the San Fernando earthquake, shaking caused a major slide of the top thirty feet of the Lower San Fernando Dam. The dam was very close to completely failing. Eighty thousand people living downstream of the dam were immediately ordered to evacuate. At the time, there were no dam failure inundation maps available showing the areas which would be affected by a dam failure, and there were no planned evacuation procedures to follow.

As a result of the near failure of the Lower San Fernando Valley Dam, the Dam Safety Act was passed into law. This new law required dam owners to create maps showing areas that would be flooded if the dam failed. The California Office of Emergency Services (OES) approves the maps and distributes them to local governments, who in turn adopt emergency procedures for the evacuation and control of areas in the event of a dam failure.

In hydraulic fills, materials are mixed with water and pumped to the fill location where they are poured into place. As the water drains, the sand settles in distinct layers that are prone to liquefaction failure. In the 1971 San Fernando earthquake, shaking and resulting liquefaction caused a major slide of the top thirty feet of the Lower San Fernando Dam. This hydraulic-fill dam was very close to completely failing. Eighty thousand people living downstream of the dam were immediately ordered to evacuate. Most hydraulic fill dams were deemed to be unsafe and have been replaced with other types of dams (usually rolled earth dams in the Bay Area). Various other standards for dam structures have been improved and applied.

Besides the passage of the Dam Safety Act, other improvements concerning dams have been made throughout California as a result of the near-failure of the Lower San Fernando Valley Dam. Hydraulic fill dams, the type of dam that the Lower San Fernando Valley Dam was, were deemed to be unsafe and have been replaced with other types of dams (usually rolled earth dams in the Bay Area). Various other standards for dam structures have been improved and applied.

The California Water Code entrusts the regulatory Dam Safety Program to the Department of Water Resources. The principal goal of this program is to avoid dam failure and thus prevent loss of life and destruction of property. Dams under State jurisdiction are an essential element of the California infrastructure that provides constant water supply integrity.

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Livermore Valley Watershed

California Department of Water Resources

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One dam poses a viable threat to the Pleasanton areas if they were to fail. State of California Office of Emergency Services and the Association of Bay Area Governments has compiled data on inundation potential for the areas in the event of a failure of the Del Valle Reservoir Dam and/or the Patterson Dam. Regular inspections and required maintenance of the dams substantially reduce the potential for catastrophic failure.

South Bay Aqueduct

Construction on the South Bay Aqueduct began in 1960. The Aqueduct was the first delivery system completed under the SWP and has been conveying water to Alameda County since 1962 and to Santa Clara County since 1965.

The South Bay Aqueduct begins at Bethany Reservoir near Tracy, with the South Bay Pumping Plant lifting water 566 feet into the first reach of the Aqueduct. The South Bay’s Pumping Plant's nine pumping units, with a combined capacity of 330 cubic feet per second, discharge water through two parallel buried pipelines to the eastern ridge of the Diablo Range. From there, water flows by gravity for nine miles to the 100 acre-foot Patterson Reservoir, where some water is released for delivery to Livermore Valley. Water flow then continues about nine miles to a junction point where a portion is diverted into a 1 1/2-mile branch line and pumped into Lake Del Valle.

Beyond the Del Valle junction, the water flows by pipeline to La Costa Tunnel, proceeds southwest past Sunol, through the Mission Tunnel, then south through the hills overlooking San Francisco Bay. South Bay Aqueduct terminates in a 160-foot diameter steel tank on a hillside five miles east of downtown San Jose.

Water agencies served by the South Bay Aqueduct — the Alameda County Flood Control and Water Conservation District (Zone 7), Alameda County Water District, and Santa Clara Valley Water District — can receive up to 188,000 acre-feet a year. Maximum annual entitlement for each contractor is: Zone 7, 46,000 acre-feet; Alameda County Water District, 42,000 acre-feet; and Santa Clara Valley Water District, 100,000 acre-feet.

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Del Valle Dam

California Department of Water Resources

The 235-foot-high Del Valle Dam impounds a reservoir with a total capacity of 77,100 acre-feet. To provide a flood control reserve, it normally stores from 25,000 to 40,000 acre-feet. (An acre-foot is 325,900 gallons, enough water to cover one acre of land one foot deep.)

Lake Del Valle and Dam Statistics Max. Normal Storage...... 40,000 acre-feet Lake Gross Capacity...... 77,100 acre-feet Surface Area...... 708 acres Elevation...... 703 feet MSL Shoreline...... 16 miles max. flood control storage Maximum Depth (normal)...... 153 feet Water Surface Elevation...... 703 feet MSL (normal maximum) Dam Structural Height...... 235 feet Crest Elevation...... 773 feet Crest Length...... 880 feet Volume...... 4,150,000 cubic yards of earthfill

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Lake Del Valle State Recreation Area

This area as 4,000 acres of park and 750 acres of lake. The area is ideal for picnicking, horseback riding, boating, fishing and swimming.

Lake Del Valle is located in Central Alameda County, about five miles south of the City of Pleasanton in the Arroya del Valle. Del Valle Dam and Lake Del Valle are features of the South Bay Aqueduct, which is part of the State Water Project

Lake Del Valle was created in 1968 to provide recreation and fish and wildlife enhancement, flood control for Alameda Creek, and regulatory storage for a portion of the water delivered through the South Bay Aqueduct.

History

A band of Ohlone Indians roamed the Del Valle area long before the Spanish missionaries and explorers set foot in California. Arrowheads and grinding stones recovered at Lake Del Valle reveal the existence of Ohlone settlements in the shadow of the Diablo Range. Lake Del Valle State Recreation Area occupies part of the 1839 Mexican land grants to the families of Agustin Bernal and Antonio Sunol (the present-day city bears his name). During the late 1800s and early 1900s, Europeans moved in and took over the lands of the original Mexican and Spanish grant holders. Foundations and rock piles from buildings from that period still stand along the old trails. Many of the early building sites are beneath the waters of Lake Del Valle.

The park is located on Del Valle Road, just a few miles south of Interstate 580 in Pleasanton.

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Local Impact

If the Del Valle Reservoir, which holds 77,100 acre-feet of water at full capacity, were to fail due to an earthquake or similar disaster, water in the dam would be released, and flooding of the Amador Valley would occur as shown the figure above. The resulting area of inundation assumes that the reservoir would be filled to the maximum, which it usually is not, and that the dam would fail suddenly and completely. Although the dam’s failure has only a very small likelihood of occurrence, the possibility exists for extensive property damage and loss of lives.

The map below depicts areas in Livermore/Pleasanton most vulnerable to inundation caused by catastrophic dam failure. The yellow area is the area that would be impacted by failure of the dam. The red outlines the inundation area.

Information from CA Dept of Water Resources

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Hazard Materials Vulnerability Threat Summary

The Livermore/Pleasanton area contains some industrial development that may be associated with hazardous materials uses. Land uses involving hazardous materials or other hazards include the airport, hazardous waste transfer facilities, paint and paint product manufacturing facilities, semiconductor manufacturers, medical device manufacturers, and petroleum product and natural gas pipelines.

In general, natural gas is believed to be less hazardous to the public than petroleum products because it is transported at lower pressures and, when released, rises and dissipates. Petroleum products are pumped at higher pressures and, when released, flow along the ground. Petroleum fires are also more likely to spread to nearby property than vertical-burning natural gas fires.

Hazardous Materials Transportation

Most hazardous materials are regularly carried on railroads and the freeways and major roads designated as explosive routes by CALTRANS and the Highway Patrol. The proximity of some of these routes to large numbers of people suggests that an accident involving hazardous materials transportation could reach disaster proportions. The extreme toxicity of some chemicals used in the area and the specialized handling and cleanup procedures required during an accident can close major thoroughfares and necessitate evacuation.

Because of its proximity to large U. S. Department of Energy facilities, the Livermore/Pleasanton area has a unique risk to public safety by the transportation of quantities of various radioactive materials. In case of an accident, small amounts of radioactive materials can be dislodged from their protective containers and become extremely difficult to locate necessitating evacuation of large areas.

The area is home to numerous businesses and industries that manufacture, store, use, and dispose of hazardous materials and hazardous waste. Some of these businesses are neighbors to urbanized population areas.

The Livermore-Pleasanton Fire Department Hazardous Materials Area Plan (separate document) contains very specific information regarding Hazardous Materials Incident potential.

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Hazardous Materials Sites & Transportation Routes

The California Health and Safety Code defines a hazardous material as, “...any material that, because of its quantity, concentration, or physical or chemical characteristics, poses a significant present or potential hazard to human health and safety, or to the environment. Hazardous materials include, but are not limited to, hazardous substances, hazardous waste, radioactive materials, and any material which a handler or the administering agency has a reasonable basis for believing that it would be injurious to the health and safety of persons or harmful to the environment if released into the workplace or the environment.” (Health and Safety Code §25501). Infectious and bio-hazardous wastes, such as those generated by medical facilities, are regulated differently under State laws and regulations, but are also discussed in this section.

As of 2002 issues related to the transportation, storage, use, generation, and disposal of hazardous materials in the City of Pleasanton are as follows. First, the regulatory agency framework associated with hazardous materials is described; next, the responsibilities of the City under the Certified Unified Program Agency program and various other hazardous materials programs are identified. Sites in the City of Pleasanton where a release of hazardous materials to the environment has been reported are also listed.

Products as diverse as gasoline, paint, solvents, film processing chemicals, household cleaning products, refrigerants and radioactive substances are categorized as hazardous materials. What remains of a hazardous material after use, or processing, is considered to be a hazardous waste. Bio- hazardous wastes are composed of medical waste which may contain hazardous or infectious materials. Of concern to all communities is the handling, transportation, and disposal of such wastes. Improper handling of hazardous materials or wastes may result in significant effects to human health and the environment.

Regulatory Agencies

Federal

The Environmental Protection Agency provides oversight and supervision for federal Superfund investigation/remediation projects, evaluates remediation technologies, and develops hazardous materials disposal restrictions and treatment standards.

State

Department of Toxic Substances Control.

The Department of Toxic Substances Control provides cleanup and action levels for subsurface contamination; these levels are equal to, or more restrictive than, federal levels. The Department of Toxic Substances Control has developed land disposal restrictions and treatment standards for hazardous waste disposal in California.

Air Resources Board.

The Air Resources Board and local air quality districts to inventory sources of over 200 toxic air contaminants, to identify high priority emission sources, and to prepare a health risk assessment for each of these priority sources.

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State Water Resources Control Board.

The State Water Resources Control Board issues regulations on how to implement underground storage tank programs. It also allocates monies to eligible parties who request reimbursement of funds to clean-up soil and groundwater pollution from underground storage tank leaks.

California Department of Fish and Game.

This agency responds to surface water pollution incidents.

California Office of Emergency Services.

The Office of Emergency Services is the state agency which develops regulations for the Hazardous Materials Business Plan and California Accidental Release Prevention Program. The Office’s State Warning Point acts as the Governor’s 911 Dispatch Center. The State Warning Point must be notified as soon as possible after an incident. The Office of Emergency Services compiles statewide statistics on spills and releases, and dispatches other regional, State, and federal agencies to the scene, if necessary.

Regional

Regional Water Quality Control Board.

The City of Pleasanton is located within the jurisdiction of the San Francisco Bay Regional Water Quality Control Board. The Regional Water Quality Control Board is authorized by the Porter-Cologne Waste Quality Act of 1969 to protect the waters of the State. The Regional Water Quality Control Board may also act as lead agency to provide oversight for sites where the quality of groundwater or surface waters are threatened and approves site closure. The Regional Water Quality Control Board also responds if, in an emergency, surface and groundwater is impacted.

Bay Area Air Quality Management District.

The City of Pleasanton is under the jurisdiction of the Bay Area Air Quality Management District, the local enforcement agency for Air Resources Board regulations. This regional agency regulates point source air pollutants, as well as mobile sources (e.g., automobiles). Bay Area Air Quality Management District staff also respond to odor and asbestos complaints, when requested by City staff or the general public.

Local

Livermore-Pleasanton Fire Department.

The Hazardous Materials Division of the Livermore- Pleasanton Fire Department, as a Certified Unified Program Agency, has primary responsibility for enforcing most regulations pertaining to hazardous materials in the City of Pleasanton. The Livermore-Pleasanton Fire Department also acts as first responder to hazardous materials incidents within the City.2

Alameda County Department of Environmental Health.

The Alameda County Department of Environmental Health may act as lead agency to ensure proper remediation of leaking underground petroleum product tank sites and certain other contaminated sites within the City of Pleasanton.

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Hazardous Materials Business Plan.

Businesses that store hazardous materials in excess of specified quantities, as set forth by City, State, and federal regulations, must report their chemical inventories to the Livermore-Pleasanton Fire Department. This information informs the community on chemical use, storage, handling, and disposal practices. It is also intended to provide essential information to firefighters, health officials, planners, elected officials, workers, and their representatives so that they can plan for and respond to potential exposures to hazardous materials.

Emergency Response.

The Livermore-Pleasanton Fire Department acts as first responder to all chemical emergencies, such as hazardous material spills that occur at businesses or on City streets, illegal dumping, complaints, or potential releases involving hazardous materials. Hazardous Materials Division staff help identify substances spilled, notify responsible State agencies concerned with such incidences, determine how the public can best be protected from any harmful effects, and may oversee site clean-up.

The Fire Department maintains the Hazardous Materials Area Plan which contains protocols and guidance for response to Hazardous Materials Incidents. The Fire Department acts as first responder to all chemical emergencies, such as hazardous material spills that occur at businesses or on City streets, illegal dumping, complaints, or potential releases involving hazardous materials. Hazardous Materials Division staff help identify substances spilled, notify responsible State agencies concerned with such incidences, determine how the public can best be protected from any harmful effects, and may oversee site clean-up.

Contaminated Site Cleanup.

The Livermore-Pleasanton Fire Department refers sites with known or suspected contamination to other agencies, such as the Department of Toxic Substances Control, Alameda County Department of Environmental Health, and Regional Water Quality Control Board, for clean-up. Contaminated site clean up is governed by State and regional regulations and policies.

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Hazardous Materials Targets

A major spill of chemicals stored in Pleasanton could cause major loss of life, injury and property damage. Hazardous materials are classified in three states: gas, solid, and liquid. They may be stored at high or low pressure and may be affected by the environment where an incident may take place.

The Livermore/Pleasanton Fire Department maintains a list of facilities in Pleasanton that have been determined to be Hazardous Materials Target Hazard Sites. The list is published in the Hazardous Materials Area Plan.

Hazardous Wastes Generated by Businesses.

Besides checking compliance with regulations and codes, Livermore-Pleasanton Fire Department staff look for obvious evidence of hazardous material releases, such as spills or staining on floor areas surrounding hazardous material storage. Inspections can also provide an opportunity for Livermore- Pleasanton Fire Department staff to provide information regarding hazardous waste minimization and current best management practices for the handling and disposal of hazardous wastes.

Household Hazardous Waste

Many of the items routinely used by Pleasanton residents, such as paints and thinners, cleaning products, motor oil, and other such items, are hazardous materials. Because they are commonly used around the house, many people are unaware of the potential hazards associated with the use and disposal of these items. An undetermined, but probably large, percentage of these materials are improperly stored and disposed of; half-finished items may be stored in kitchens, garages or basements, or may be poured down storm drains, dumped into the garden, or placed into the household garbage can. None of these disposal methods is satisfactory as they expose the occupants and others, to unnecessary risks and could potentially contaminate soils and groundwater at transfer stations and solid waste disposal sites.

Medical Wastes.

Medical waste is defined as bio-hazardous waste, sharps waste, or waste which is generated or produced as a result of the diagnosis, treatment, or immunization of human beings or animals, in medical research, or in the production or testing of biological materials. Medical waste may also contain infectious waste. In the City of Pleasanton, the State enforces the Medical Waste Management Act. The Medical Waste Management Act establishes handling, tracking, storing, hauling, treating and disposal requirements for medical waste. Typical medical waste generators regulated by the Act include hospitals, nursing homes, veterinarians, laboratories, clinics, dentists, and physicians. Medical waste generators who generate more than 200 pounds of medical waste per month and/or perform on- site treatment of medical wastes must register with the State.

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Hazardous Materials Transportation

In addition to the hazards of stored chemicals, there are hazards of transporting chemicals into and through the area. Accidents involving the transportation of chemicals could be just as catastrophic as accidents involving stored chemicals, possibly more so, since the location of a transportation accident is not predictable.

The Union Pacific/Southern Pacific and Western Pacific Railroads conduct rail operations in the Pleasanton area. Cargoes of electronics, fabricated metals, plastics, precision machinery, agricultural chemicals, construction materials, rock/sand/gravel aggregates and other hazardous materials are also shipped over the rail lines.

A spill of bulk hazardous materials could result in fire, explosion, toxic cloud or direct contamination of people and property. The effects may involve a local site or many square miles. Health problems may be immediate, such as corrosive effects on skin and lungs, or be eventual, such as the development of cancer from a carcinogen. Damage to property could range from immediate destruction by explosion to permanent contamination by a persistent hazardous substance.

The I-580 corridor affords a large amount of truck movement from the Bay Area to the Central Valley. At its eastern end, it connects to Interstate 5, the major north-south route through California, and at its west end, Interstate 80, the major east-west route through Northern California. The weigh station operated by the California Highway Patrol at Vasco Road reports that, on a month-by-month basis, an average of 25,000 trucks pass through that facility. Approximately 8% of those trucks, or 2,000 trucks per month, display hazardous materials placards. Assuming each vehicle had an average load weight of 35,000 pounds… that would convert to approximately 35,000 tons of placarded material a month moving through the I-580 corridor.

The map on the next page shows transportation routes, target facilities and pipelines.

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ONS a ni ABILITY LOCATI r R , Califo n VULNE S nto L sa Plea MATERIA RDOUS HAZA

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