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Past earthquakes, wildfires, floods, and landslides have exposed Glendale's residents and businesses to the financial and emotional costs of recovery. These same natural hazards have the potential to pose a future negative impact on the citizens, property, environment, and economy of the city of Glendale. Furthermore, as more people move to areas vulnerable to these hazards, the risk associated with these natural hazards increases. The historical record shows that even in those parts of the community that are essentially "built-out" (i.e., have little or no vacant land remaining for development), population density continues to increase as low-density housing is replaced with medium- and high-density development projects. This in effect places even more people at risk from the hazards that can impact the area.
Given that natural hazards are inevitable, and that populations in hazardous areas are increasing in response to development pressures, there is an urgent need to develop strategies, coordinate resources, and increase public awareness to reduce the risk and losses from future natural hazard events. Identifying the risks posed by natural hazards, and developing strategies to reduce the impact of a hazard event can assist in protecting life and property. In Glendale, local residents and businesses can work together with the City to create a natural hazards mitigation plan that addresses the potential natural hazards of most concern to Glendale.
Geography and the Environment
The city of Glendale is located in northeast Los Angeles County at the eastern end of the San Fernando Valley. The city has a total area of 30.7 square miles of developed and undeveloped land and is characterized by sharp contrasts in terrain. Distinct topographic features separate the city into four specific areas. From north to south these include: 1) the steeply rising range front of the San Gabriel Mountains, 2) the gently south-dipping but elevated alluvial fan surface known as the La Caņada Valley at the base of the San Gabriel Mountains, 3) the lower, but not less impressive, bedrock highlands of the Verdugo Mountains and the San Rafael Hills, and 4) the even more gently south-dipping alluvial surface (piedmont) at the base of the Verdugo Mountains. Farther south, just outside city limits, is the northeastern end of the Santa Monica Mountains, which are locally referred to as the Hollywood Hills.
Elevations in the southern part of the city range from about 420 feet above mean sea level at its southernmost point to about 800 feet at the base of the Verdugo Mountains. Mount Verdugo reaches an elevation of 3,126 feet, whereas the top of Flint Peak in the San Rafael Hills sits at an elevation of 1,889 feet. In the San Gabriel Mountains, the highest point within the city is at an elevation of about 4,800 feet.
The city is served by the 210, 134, 5 and 2 freeways. Its major arterial highways include Chevy Chase Drive, Glendale Avenue - Verdugo Road - Canada Boulevard - La Crescenta Avenue, Brand Boulevard, Central Avenue, and San Fernando Road, which run generally north to south, and Foothill Boulevard, Honolulu Avenue, Glenoaks Boulevard, Broadway, Colorado Street, and Chevy Chase Drive, which run primarily east to west (see Map 2.1).
Passenger transportation is provided by the Beeline Transit System, Metropolitan Transportation Authority (MTA) bus lines, the MTA Gold Line light rail system, Metrolink, City of Los Angeles Department of Transportation LADOT shuttle and commuter express buses, and Glendale's Dial-a-Ride Program.
Map 2.1: Freeways and Major Arterial Highways in the Glendale Area
Major Rivers
The nearest major river to Glendale is the Los Angeles River, located at its closest reach about 0.5 miles west of the southern one-third of the city. The Los Angeles River hugs the north side of the Hollywood Hills as it flows easterly through the area; when it reaches the eastern end of the hills, the river veers south to flow through the "Narrows" and the city of Los Angeles on its way to the Pacific Ocean. The two heavily populated alluvial surfaces at the base of the Verdugo and San Gabriel Mountains are linked by the south-trending canyon carved by the Verdugo Wash that separates the Verdugo Mountains on the west from the San Rafael Hills on the east.
The steep southern flank of the San Gabriel Mountains is deeply incised by gorges and canyons that drain south into the La Caņada Valley, where they have been channelized, conveying their flows south to Verdugo Wash (see Plate H-1: Geomorphic Map of Glendale in Appendix H). The three canyons that are located mostly within city limits include Ward, Dunsmore, and Cooks. Several other streams draining the San Gabriel Mountains are also channelized through the La Crescenta area and into the northern portion of Glendale; these include the Eagle Canyon, Pickens, Hills and Winery Canyon channels. Nearly all the tributaries flowing northerly and easterly out of the Verdugo Mountains and westerly out of the San Rafael Hills empty into Verdugo Wash. South of the mountains, Verdugo Wash turns to the west-southwest and joins the Los Angeles River near the junction of Highway 134 with the 5 Freeway (Interstate 5). Drainage from the southwestern slope of the Verdugo Mountains flows directly across the alluvial fan and into the Los Angeles River. Verdugo Wash has been confined to a man-made channel through most of Glendale to reduce its potential to flood the city.
Climate
The city of Glendale enjoys a mild climate with an average high temperature of 77 degrees Fahrenheit. Temperatures in the city generally range from a low of 43 degrees in the winter months to a high of 90 degrees in the summer months. However, Santa Ana winds can bring higher temperatures and very low humidity. Temperatures rarely exceed 100 degrees in the summer months (June - September), and rarely drop below 30 degrees in the winter months (November-March).
Rainfall in the city averages 17.8 inches of rain per year (see Table 2.2). The term "average rainfall" is misleading, however, because over the recorded history of rainfall in Glendale, rainfall amounts have ranged from one-third the normal amount to more than double the normal amount. Furthermore, rainfall in Glendale, as in most of southern California, tends to fall in large amounts during sporadic and often heavy storms rather than consistently in several moderate storms at somewhat regular intervals. In short, rainfall in southern California might be characterized as "feast or famine" within a single year.
Rocks and Soil
The properties of the rocks and soils underlying the city of Glendale determine to some extent the potential geologic hazards that may occur in the area, such as the susceptibility of an area to earthquake-induced liquefaction, expansive soils, and landslides. Therefore, understanding the geologic characteristics of the bedrock and soils of Glendale is an important step in hazard mitigation and avoiding at-risk development. The types and characteristics of the bedrock, unconsolidated sediments (weathered rock material), and soil that underlie the city also reflect the geologic and climatic processes that have affected this region over the past few million years.
The most striking geologic features of the Glendale area are the Verdugo and San Gabriel Mountains, ranges that form a dramatic backdrop to the southern and northern portions, respectively, of the city. These rugged, geologically young uplands consist of a series of predominantly east-west trending mountain ranges and intervening valleys. The mountains are made up of various bedrock types, including igneous (granite and diorite) and metamorphic (gneiss and quartzite) rocks (see Plate H-2: Geologic Map of Glendale, in Appendix H). As these bedrock types weather and break down over time, they form unconsolidated sediments consisting of silt-, sand-, and gravel-sized pieces of granite and gneiss. These unconsolidated sediments are transported into the intervening valleys by running water, gravity, and wind, where they are deposited on the floodplain and fans as alluvium and fan material. This process has been occurring for thousands of years, and some of the earliest alluvium (referred to as older alluvium), which crops out in the La Caņada Valley and the piedmont surface south of the Verdugo Mountains, has developed secondary clay minerals that make the deposits weakly consolidated, and with a slightly red color as a result of some of the iron minerals turning to rust.
Other Significant Geologic Features
The city of Glendale, like most of the Los Angeles Basin, overlies or is near to several known faults capable of producing damaging earthquakes. The major faults that have the potential to affect the city of Glendale include the Sierra Madre, Verdugo, Hollywood, Raymond, Puente Hills Blind Thrust, San Andreas, San Gabriel, Newport-Inglewood, and Palos Verdes faults (refer to Section 6, see Map 2-2, and Plate H-4 in Appendix H). The San Gabriel Mountains are being uplifted along the Sierra Madre fault zone, whereas the Verdugo Mountains are being uplifted along the Verdugo fault. Uplift of these mountains accelerated in mid-Pleistocene time, about 500,000 years ago, continues today, and is one of the fastest in the world, in the context of geologic time.
The Los Angeles Basin experiences many small tremors every year, but its history has been shaped by several relatively infrequent, but powerful earthquakes. The first historical earthquake was recorded in 1769, when the Portola expedition was camped next to the Santa Ana River in what is now the city of Orange, but earthquakes undoubtedly have shaken the area for millennia. Other more recent earthquakes were recorded in 1812, 1857, 1933 (Long Beach), 1987 (Whittier), and 1994 (Northridge). The 1857 Fort Tejon event was a large magnitude 8+ earthquake on the San Andreas fault that caused only minor damage because the epicentral area was largely unpopulated. A similar-sized earthquake today would result in thousands of casualties and billions of dollars in property loss. Given that paleoseismological research indicates that great earthquakes (i.e., M8.0+) occur on the San Andreas fault at intervals between 45 and 332 years, with an average interval of 140 years, another similar M8 earthquake on the San Andreas fault is considered likely in the not-too-distant future. This fact alone should encourage local governments to strengthen their infrastructure and prepare for "the Big One." Furthermore, as we will discuss in this document, there are other lesser-known faults closer to Glendale that have the potential to cause more damage to the city than the more distant San Andreas fault. The earthquake hazard to the Los Angeles basin and the cities therein is severe.
Map 2.1: Regional Active and Potentially Active Faults near Glendale
In addition, many areas in the Los Angeles basin, including the city of Glendale, have sandy soils that are subject to liquefaction. The liquefaction-susceptible zones in the city of Glendale are shown on Plate H-5 (Appendix H). These zones include the youthful sandy sediments of Verdugo Wash and La Caņada Valley, along the Los Angeles River floodplain in the southwest part of the city, and in the bottom of the smaller canyons emanating from the Verdugo Mountains and the San Rafael Hills, such as Scholl and Sycamore canyons.
The city of Glendale also has areas of slope instability potential. Evidence of past slope failures are found throughout the mountain- and foothill-regions of the city. The crystalline bedrock of the San Gabriel Mountains, weakened by fracturing, shearing, and crushing along numerous fault zones, particularly near the range front, combined with the moderate to extremely steep slopes that have resulted from rapid uplift of the mountains, are important elements that create the setting for the development of slope failures. Similar conditions are present in the Verdugo Mountains and the San Rafael Hills, where rocks are highly weathered and slope gradients of 30 degrees or steeper are common. Unfortunately, detailed maps showing previous sites of surficial slope failures, such as small landslides, slumps, soil slips, and rockfalls have not been compiled or published for the Glendale area. However, an unpublished engineering geology report records several talus rockfalls on steep slopes and roadcuts in the Verdugo Mountains (R. T. Frankian & Associates, 1968). The common occurrence of rockfalls can also be inferred by the abundant talus at the base of steep slopes and in canyons of the San Gabriel Mountains. Significantly, however, areas of gross instability such as large deep-seated landslides have not been mapped in the Glendale area, primarily because the highly fractured crystalline rocks that underlie the San Gabriel and Verdugo Mountains and the San Rafael Hills rarely fail as large cohesive units. All of the landslides mapped within city limits are relatively small in area, and limited to the Verdugo Mountains and San Rafael Hills. The larger of these landslides are shown on Plates H-2 and H-11 (in Appendix H). The distribution of existing landslides in the Glendale area and vicinity was compiled from various publications, including Morton and Streitz, (1969), Crook et al. (1987), and Dibblee, (1989a, 1989b, 1991a, 1991b, 2002).
Community History
Glendale has an ethnically diverse and rich cultural heritage that dates back to the 1700s. The first known inhabitants of the Glendale area were the native Americans known as the Gabrielinos. In 1784, Corporal Verdugo of the Spanish Army received permission to settle on this land, and by 1798 he had received title to the land and was a full-time rancher and farmer. Over the next 90 years, Verdugo's descendants divided and sold off the ranch. In 1884, the area residents decided to form a town and chose the name "Glendale." The city of Glendale was incorporated in 1906.
Population and Demographics
According to the 2000 Census data, in the year 2000 the city of Glendale had a population of 194,973. The city's population steadily increased from 1940 through 1990 after a sharp increase of about 50,000 between 1930 and 1940 (see Table 2.3 below). Although population growth continued in the 1990s, the city's growth rate slowed to about 8 percent from 1990 to 2000 from an average of about 20 percent per decade for the previous 50 years. The California Department of Finance projects a continued 5 to 7 percent population increase per decade for the near future in Glendale. This population is not evenly distributed throughout the city's 30.7 square miles, but is rather concentrated in the lowland portions of the city, south of the Verdugo Mountains, and between the Verdugo Mountains to the south and the San Gabriel Mountains to the north. Over the years, Glendale has experienced in-fill development, increasing its population density. This creates greater service loads on the built infrastructure, including roads, water supply, sewer services and storm drains, and existing services.
An increase in population creates more community exposure in the face of natural hazards, and changes how agencies prepare for and respond to natural hazards. For example, more people living at the wildland/urban interface, such as in the Verdugo Hills of Glendale, can increase the risk of wildland fire. This increased potential for wildfires results from the fact that most fires are caused by human activities, and as there are more people living and playing in the interface, there are more opportunities for fires to get started. At the same time, a larger number of people at the wildland/urban interface means that more people are exposed to and can therefore be injured by fire, and there is also an increased potential for property damage.
Urban/wildland fires are not the only concern in Glendale. In the 1987 publication, Fire Following Earthquake issued by the All Industry Research Advisory Council, Charles Scawthorn explains how a post-earthquake urban conflagration would develop. The conflagration would be started by fires resulting from earthquake damage, but made much worse by the loss of pressure in the fire mains, caused by either lack of electricity to power water pumps, and/or loss of water pressure resulting from broken water mains. Furthermore, increased density can affect risk. High-density housing increases the chances of fire spreading from one structure to the next. Also, narrow streets in residential areas (and especially in the hillside areas) are more difficult for emergency service vehicles to navigate, and the higher ratio of residents to emergency responders affects response times.
Natural hazards do not discriminate, but the impacts in terms of vulnerability and the ability to recover vary greatly among the population. According to Peggy Stahl of FEMA's Preparedness, Training, and Exercise Directorate, 80 percent of the disaster burden falls on the public, and a disproportionate percentage of the burden is placed upon special needs groups, including the elderly, women, children, minorities, and the poor. As the recent events associated with the hurricane Katrina in the Gulf Coast have shown, vulnerable populations, including seniors, disabled citizens, women, and children, as well as those people living in poverty, are often disproportionately impacted by natural hazards.
Present-day Glendale is a racially and ethnically diverse community, (see Table 2.4 below). For the 2000 Census, the U.S. Census Bureau introduced new racial categories, which allowed respondents greater flexibility in how they define themselves. Between the 1990 and 2000 Census, the percentage of "whites" in Glendale dropped about 10 percent, which approximately coincides with the percentage of people who define themselves as being of "two or more races." Also, between 1990 and 2000, the number of Armenians and Asians increased from 17 to 27 percent and 14 to 16 percent, respectively, of Glendale's total population. The number of Hispanics (any race) dropped from 21 to 19 percent of the population. It should be noted that Hispanic ethnicity is a separate data category from race and is therefore not included on a separate line in Table 2.4. The ethnic and cultural diversity suggests a need to address multi-cultural needs and services.
The percentage of individuals living in poverty in the city of Glendale is 15.5 percent, which is higher than the State's 12.9 percent. Of those people living below the poverty line in Glendale, 20.7 percent of them are less than 18 years old, and 11.9 percent are over the age of 65 (see Table 2.5 below for more specific information). The number of Glendale families below the poverty line is about 13.6 percent of the total population, or 6,802 families. Most live in the central and southern parts of the city.
Examining the reach of hazard mitigation policies to special-needs populations may assist in increasing access to services and programs. FEMA's Office of Equal Rights addresses this need by suggesting that agencies and organizations planning for natural disasters identify special-needs populations, make recovery centers more accessible, and review practices and procedures to remedy any discrimination in relief application or assistance.
The cost of natural hazards recovery can place an unequal financial responsibility on the general population when only a small proportion may benefit from governmental funds used to rebuild private structures. Discussions about natural hazards that include local citizen groups, insurance companies, and other public and private sector organizations can help ensure that all members of the population are a part of the decision-making processes.
Land and Development
In the earliest days, development in southern California was a cycle of boom and bust. The Second World War, however, dramatically changed that cycle. Military personnel and defense workers came to southern California to fill the logistical needs created by the war effort. The available housing was rapidly exhausted and existing commercial centers proved inadequate for the influx of people. Immediately after the war, construction began on the freeway system, and the face of southern California was forever changed. Home developments and shopping centers sprung up everywhere, and within a few decades the central basin of Los Angeles County was virtually built out. This pushed new development farther and farther away from the urban center.
Glendale's General Plan addresses the use and development of private land, including residential and commercial areas. This plan is one of the City's most important tools in addressing environmental challenges, including transportation and air quality, growth management, and the conservation of natural resources such as clean water and open spaces. However, the environment of most cities in Los Angeles County is nearly identical with that of their immediate neighbors and the transition from one incorporated municipality to another is often seamless to most people. This means that many of the environmental challenges listed above need to be addressed on a regional scale, rather than on a city-by-city basis, to effect change. Similarly, the area's exposure to natural hazards is similar to that of several neighboring communities, but a city's response to that vulnerability can often be addressed independently. For example, liquefaction susceptible sediments underlie large portions of the Los Angeles River floodplain, oblivious to corporate boundaries. However, a city can choose to implement more strict building codes to study and mitigate the hazard posed by liquefaction, or even restrict development in the most highly susceptible areas, thereby reducing its risk to a level below that of adjoining municipalities with a similar susceptibility but less stringent development codes.
Housing and Community Development
Housing stock is many direct and indirect ways one of the most important commodities in a city. If a natural disaster, such as an earthquake, flood or landslide, damages several houses, this has a significant impact not only on the residents of those structures, but on the City also. An extreme, but real example of this is New Orleans; a year after Katrina, entire neighborhoods are vacant, the houses still in ruin. Past residents of these communities have started new lives in other cities and states and many do not plan to come back, substantially diminishing New Orleans' tax base, and hindering the City's ability to rebuild and recover.
In the year 2000, the median value of homes in the city of Glendale was estimated at $326,700 (2000 Census). However, the demand for housing has outpaced the available supply, and the recent low interest rates have further fueled this demand. As a result, in 2004, the median home price in Glendale was estimated to be over $557,000, which is about a 70 percent jump in value from the 2000 values. Even at these prices, the demand for low- to medium-priced homes continues to be strong, given the few existing homes available. There are approximately 73,611 total housing units in the city of Glendale. Of these, 29,492 (40 percent) are single-family homes, 7,276 (10 percent) are condominiums, and 36,843 (50 percent) are apartments. Seventy-six (76) percent of these housing units were built before the 1980s, before the more recent (and stringent) building and fire codes for public safety were adopted. To address development issues, Glendale's Department of Community Development and Housing has engaged in activities that promote the quality of life for the citizens of the city of Glendale. The large-scale effort includes neighborhood and other public facility improvements, rehabilitation of existing housing, new housing development, and home purchase assistance.
There is an increased concentration of resources and capital in Glendale. The best indicator of this is the increasing per-capita income in the region since the 1970s. Per-capita income is an estimate of total personal income divided by the total population. This estimate can be used to compare economic areas as a whole, but it does not reflect how the income is distributed among residents of the area being examined. For example, the City's per-capita income has been increasing at a faster rate than that of California and the United States, and yet, as reported above, Glendale also has a relatively large percentage of population living below the poverty level. This shows that wealth in the area is distributed unevenly among different segments of the population.
Subtle but very measurable changes occur constantly in communities that increase the potential loss that will occur in a major disaster. There are a number of factors that contribute to this increasing loss potential. First, populations continue to increase, putting more people at risk within a defined geographic space. Second, inflation constantly increases the worth of real property and permanent improvements. Third, the amount of property owned per capita increases over time. Information from the U.S. Census Bureau shows gains in average housing standards in the United States (Table 2.6).
If we look at the greatest recorded earthquakes in American history, and compare the level of population and development today with that which existed at the time of these events, the scale of potential damage is staggering (Source: Risk Management Solutions).
- 1886 Charleston, South Carolina M7.3 earthquake
Estimated insured damage if it happened today: $10 Billion
- 1906 San Francisco earthquake, significant fire following seismic damage
Estimated insured damage if it happened today: $36 Billion
- 1811-12 New Madrid, Missouri earthquakes, series of 4 earthquakes over 7 weeks
Estimated insured damage if this happened today: $88 Billion
Employment and Industry
Glendale's principal employment and industrial activities include service industries, manufacturing, retail, entertainment, tourism, and commerce. The city's business climate has been strong and growing with concentrations of retail and wholesale trade, professional services, and real estate firms. Glendale provided over 91,500 jobs in 2000. Education and health-related services accounted for the largest percentage (19.9%), followed by professional services (12%), retail trade (11.4%), and manufacturing (10.6%). Occupations of persons 16 years and older, per the 2000 Census, are apportioned as listed in Table 2.7.
Mitigation activities are needed at the business level to ensure the safety and welfare of workers and limit damage to industrial infrastructure. Employees are highly mobile, commuting from surrounding areas to industrial and business centers. This creates a greater dependency on roads, communications, accessibility and emergency plans to reunite people with their families. Before a natural hazard event, large and small businesses can develop strategies to prepare for natural hazards, respond efficiently, and prevent loss of life and property.
Transportation and Commuting Patterns
The city of Glendale is the 3rd largest, based on its population, in the Los Angeles Metropolitan Statistical Area (LAMSA). Over the past decade, the LAMSA experienced rapid growth in employment and population. There has been a constant increase in vehicle licensing transactions in the Los Angeles region (see table 2.8).
Private automobiles are the dominant means of transportation in southern California and in the city of Glendale. However, Glendale meets its public transportation needs through a mixture of a regional transit system (MTA) of bus lines and light-rail system (MTA Gold Line), Metrolink, the City of Los Angeles Department of Transportation LADOT shuttle and commuter express buses, and the City-contracted bus system (Beeline Transit System) which serves 1.7 million riders a year. In addition, the City provides curb-to-curb transportation for 54,000 elderly or disabled residents, and promotes alternative transportation activities.
Glendale has included a mobility plan in its General Plan. The City benefits from a diverse transportation system that includes transit, bicycle, and pedestrian links, as well as vehicular links. The City's local system connects with the larger regional system, and the operation of the two systems is interdependent. The mobility plan establishes how the City manages the local system to provide for the safe and convenient movement of people and goods. It also addresses how the City influences and manages connections with the regional transportation system.
The vision of the mobility plan is to promote a livable community where people can circulate without cars. Consistent with this principle, the mobility plan has four primary objectives that guide how the City's transportation system is managed:
- Promote a livable and economically strong community;
- Encourage non-auto travel;
- Protect neighborhoods by discouraging traffic from passing through neighborhoods; and
- Manage multimodal corridors to improve citywide transportation services.
As noted above, one of the key components of the mobility plan is the encouragement of non-auto modes of transportation, such as transit, bicycling, car-sharing, and walking. Increasing the use of non-auto travel options yields numerous community benefits including reduced traffic, less need for costly roadway improvement projects, a more enjoyable pedestrian environment, and improved air quality.
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