HomeMy WebLinkAboutRes 1734 - Hazard Mitigation PlanCity of Tukwila
Washington
Resolution No. 1
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF TUKWILA,
WASHINGTON, ADOPTING THE TUKWILA HAZARD MITIGATION PLAN.
WHEREAS, the City of Tukwila and surrounding areas are subject to various
hazards, including flooding, earthquakes, landslides, severe windstorms and other
natural and technological /man -made hazards; and
WHEREAS, the City of Tukwila is committed to strengthening the City's resilience to
the effects of natural and technological /man -made hazards; and
WHEREAS, the Federal Disaster Mitigation Act of 2000, specifically Section 322,
addresses local mitigation planning and requires local governments to develop Local
Hazard Mitigation Plans as a condition of receiving Hazard Mitigation Grant Program
funding, Flood Management Assistance, and Pre - Disaster Mitigation funding from the
Federal Emergency Management Agency (FEMA); and
WHEREAS, FEMA has completed a pre- adoption review of the City's Hazard
Mitigation Plan and will approve the Plan upon receiving documentation of its adoption
by the City;
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF TUKWILA,
WASHINGTON, HEREBY RESOLVES AS FOLLOWS:
The City Council approves participation in the hazard mitigation planning process,
development of a City -wide Hazard Mitigation Plan and adoption of the final FEMA-
approved Hazard Mitigation Plan, hereby incorporated by reference as "Attachment A."
PASSED BY THE CITY COUNCIL OF THE CITY OF TUKWILA, WASHINGTON, at
a Regular Meeting thereof this rr1 H day of }-e vt.a,y , 2011.
ATTES /AUTHENTICATED:
Christy O'FIa erty, CMC, City erk
APPROVED AS • M BY:
orney
Allan Ekberg, Council Pr'sident
Filed with the City Clerk: rai
Passed by the City Council: -II
Resolution Number: , r):9
W: \Word Processing \Resolutions \Hazard Mitigation Plan.docx
Fl:mrh 01/25/2011
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CITY OF TUKWILA
HAZARD MITIGATION PLAN
EXECUTIVE SUMMARY
Historically, Tukwila and the surrounding communities have experienced the
effects of natural and technological /manmade hazards. The most prevalent
natural hazards that have affected the City are flooding, earthquakes, severe
winter storms and landslides. All of these hazards have caused property
damages and financial impacts and will continue to pose some threat to Tukwila
residents, businesses, visitors, workers and properties.
This five -year Hazard Mitigation Plan was developed to strengthen the City's
resilience by reducing risk and preventing loss. The Plan identified and assessed
the potential impact of sixteen (16) natural and technological /manmade hazards
that threaten residents, businesses, workers, visitors and properties in Tukwila.
The hazards were profiled and evaluated based on their frequency of occurrence
and impact to the Community. Based on the conclusion drawn from the Hazard
Vulnerability Analysis, Tukwila's highest risk is flooding followed by severe
windstorm, earthquake, snow /ice storm, and landslide.
The process of identifying and assessing the risks that potential hazards have in
our community has resulted in the development of a mitigation strategy that is
tied to six goals (Protect Life and Property, Support Emergency Services,
Increase Public Awareness, Preserve Natural Systems and Resources, Encourage
Partnerships, and Enhance Planning Activities). Vital to the City's mitigation
strategy are three major components:
Continuation and Enforcement of City Codes, Policies, Plans, and
Programs. The City needs to continue administering, implementing, and
enforcing the latest building codes and floodplain regulations.
Additionally, the City must continue maintaining compliance and good
standing in the National Flood Insurance Program (NFIP).
Investment of Resources. The City has recently invested over $2 million
in flood mitigation initiatives. To meet the goals and objectives outlined in
this Plan more funding would be required. State and Federal grants must
be aggressively pursued to accomplish priority mitigation projects.
Implementation of Mitigation Initiatives. For this five -year Mitigation Plan,
the City will focus on the following mitigation initiatives:
Priority 1: Construction of a permanent City EOC
Priority 2: Retrofit /Replace City Facilities
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Priority 3: Boeing Access Road Bridge Replacement
Priority 4: Interurban Ave S Project Containment Wall Construction
It is virtually impossible to predict exactly when and where disasters may occur,
or the extent to which they will affect the City. However, with planning,
collaboration among public agencies, private sector organizations and Tukwila
citizens, and an integrated mitigation strategy, it is possible to reduce, or
eliminate the long -term risk to human life and property from hazards. For the
first time in years, Tukwila has witnessed unprecedented planning, collaboration,
and cooperation with regional partners, Tukwila citizens and the business
community in mitigating the effects of potential flooding from the problems
associated with the Howard Hanson Dam.
This is Tukwila's first Hazard Mitigation Plan. When approved by the Federal
Emergency Management Agency (FEMA) and adopted by the City, this Plan will
serve as a living, stand -alone document that will continue to be improved and
updated in accordance with Section XII of this document.
Once the Plan is adopted by Resolution, the City will meet all requirements of the
Disaster Mitigation Act of 2000 (DMA 2000). Under DMA 2000, local
governments with a FEMA- approved Hazard Mitigation Plan would be allowed to
apply for and receive disaster mitigation project grants under the Hazard
Mitigation Grant Program (HMGP), and Pre Disaster Mitigation (PDM) Program.
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1. Planning Process
The plan development process began in June 2009 when the City was invited by
King County Emergency Management Department to participate in the update of
the 2004 King County Regional Hazard Mitigation Base Plan. The City's
Emergency Management Director designated the Deputy Public Works Director
as the lead City representative to work with the King County Regional Hazard
Planning Team which consisted of twenty -seven agencies from cities, fire
districts, school districts and utility districts. These agencies served as a steering
committee for the Regional Plan update.
As part of the planning effort to update the Regional Plan, the twenty -seven
representatives participated in group sessions and meetings to collect and
develop data, provide input, review plan documents, discuss critical requirements
for plan approval, and submit documentation confirming their intent to adopt the
final approved plan. Participants also met with Washington State Emergency
Management Division representatives to review draft plans, discuss FEMA
requirements, identify gaps and make necessary changes.
Initially, the participating agencies had focused on developing individual plan
annexes that would be integrated into the King County Regional Plan and then
submitted to the State and FEMA for approval. Due to the delay on the
completion of the Regional Plan, the City proceeded to develop its own stand-
alone plan.
The development of Tukwila's Hazard Mitigation Plan was accomplished through
input and collaboration with the Tukwila's Emergency Management Team (Fire
Chief, Assistant Fire Chief, Police Chief, Assistant Police Chiefs, Public Works
Director, Deputy Public Works Director, and Emergency Management Director),
review of existing City documents including the Capital Improvement Program,
Comprehensive Surface Water Management Plan, Operating Budget,
Comprehensive Emergency Management Plan, Tukwila's Hazard Identification
and Vulnerability Analysis (HIVA) document, after action reports, input from City
subject matter experts, and information provided by local, state, and federal
organizations. The Hazard Mitigation Plan was also discussed during an
Emergency Management Council meeting. See meeting minutes at Attachment
1. Members of the Emergency Management Council include the Mayor, City
Administrator, Emergency Management Director and the department directors.
With the significantly increased flood risk in the Green River Valley due to the
seepage issues at the Howard Hanson Dam, the City has participated in
numerous mitigation planning meetings at the local and regional level. The City
conducted several public meetings and outreach efforts to discuss flood risks,
mitigation activities at the local and regional level and preparedness measures.
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During a public meeting with the residential neighborhood along the
Green /Duwamish River, residents were informed of the various flood protection
options being considered for their community and the draft Hazard Mitigation
Plan that the City has developed. See meeting agenda at Attachment 2. The
planning process has resulted in the accomplishment of several flood mitigation
initiatives including the placement of flood protection devices to increase levee
capacity, and completion of priority capital improvement projects.
This is Tukwila's first Hazard Mitigation Plan. The Plan was discussed in an open
meeting during the February 17, 2010 Finance and Safety Committee Meeting
(Attachment 3) and was posted on the City's website for four weeks to allow
public comments (Attachment 4). A notice inviting residents, businesses,
neighboring jurisdictions, interested parties, and the general public to view and
comment on the draft Plan was published in the Seattle Times on February 25,
2010 and March 10, 2010. Two comments from the public were received. One
comment (add two City facilities to the critical infrastructure list) was integrated
into the final Plan.
Upon approval by FEMA, this Plan will be sent to the City of Tukwila Finance and
Safety Committee, Committee -of- Whole, and Regular Council Meetings. The
Plan will ultimately be adopted by the Tukwila City Council through a formal
resolution. A draft resolution is included at Attachment 5.
1I. Goals and Objectives
The fundamental mission of this Plan is to reduce the effects of natural and
technological and other manmade disasters in the City of Tukwila. This mission
and the following supporting goals and objectives parallel the mission, goals and
objectives developed by the Regional Hazard Mitigation Plan Steering Committee.
a. Goal One: Protect Life and Property.
Implement activities that assist in protecting lives and property by
making homes, businesses, infrastructures, critical facilities, and other
community assets more resistant to losses from hazards.
Incorporate effective mitigation strategies into the City's Capital
Improvement Program.
Integrate new hazard and risk information into building codes and
land use planning.
Maintain essential services, facilities and infrastructures during
disasters.
Identify populations with special needs or those vulnerable to the
impacts of disasters.
Reduce losses and repetitive damages from chronic hazard events.
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Consider known hazards when siting new facilities.
Develop or improve emergency warning and notification systems.
b. Goal Two: Support Emergency Services.
Participate in local and regional emergency response exercises.
Protect and maintain critical facilities, infrastructure and services
critical to emergency and disaster response activities.
c. Goal Three: Increase Public Awareness.
Conduct education and public outreach meetings and programs to
increase the public's awareness about disaster preparedness,
mitigation, emergency response, and recovery activities.
Enhance the public's knowledge about the hazards that could occur in
the region and how those hazards could impact the community.
Develop education strategies, programs and materials to assist
vulnerable populations and those with special needs.
Provide and support comprehensive education activities that address
all sectors of the Tukwila community.
Partner with private sector to promote employee education about
disaster preparedness at the jobsite and at home.
d. Goal Four: Preserve Natural Systems and Resources.
Protect agriculture, fish, wildlife, and natural resources.
Balance natural resource management, and land use planning with
hazard mitigation to protect life, property and the environment.
e. Goal Five: Encourage partnerships.
Strengthen communication and participation among public agencies,
citizens, businesses and industry.
Coordinate hazard mitigation planning efforts with other local and
regional organizations involved in disaster preparedness, response and
recovery activities.
Consider participating in the King County Regional Hazard Mitigation
Plan update process.
f. Goal Six: Enhance Planning Activities.
Improve data collection and evaluation processes for identifying
critical facilities, infrastructure, essential services, and populations at
risk.
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Improve hazard assessment information and resources.
Facilitate ongoing review and implementation of this Plan.
Actively monitor and evaluate the status, implementation and
completion of mitigation action items.
Review, update and enhance this Plan.
III. Profile
The City of Tukwila lies in the heart of the Puget Sound region, sitting 12 miles
south of downtown Seattle, 17 miles north of downtown Tacoma, and at the
crossroads of two major interstate highways, I -5 and I -405. The City is made up
of several geographically distinct areas. Most notably are the valley floor
through which the Green River flows, and the West Hill that rises up out of the
valley. Residential development and supporting commercial activity are
predominant on the West Hill areas, with the major industrial area and central
business district located on the valley floor. Its strategic location makes Tukwila
an ideal site for over 2000 businesses that currently provide retail,
manufacturing, industrial, technology and professional services for this region.
Tukwila was once a farming community and is located within the Green River
Valley. The landscape of Tukwila changed radically after the Howard Hanson
Dam was completed in 1962, allowing the Valley bottom to fill with commercial
interests as the regional economy grew. Today, the Valley is filled with
businesses, multifamily households and single family residences.
The City was incorporated on June 23, 1908. The population was approximately
400 people. Due to annexations, the population of Tukwila grew over 300% in
1989 from 4,500 to more than 14,500. Tukwila has an estimated population
growth of 1% per year and currently has approximately 18,000 people.
The demographic composition of Tukwila has changed over the years. According
to the 2000 Census, Tukwila is one of King County's most ethnically diverse
cities, with a larger population born outside of the United States. As of 2000,
4,512 (26.2 of Tukwila residents were foreign born. The number of people
speaking a language at home other than English was 5,105 (29.7% of Tukwila's
total population in 2000) and 2,759 (17.3 reported that they speak English
less than "very well
The 2000 U.S. Census found that Tukwila residents live primarily in rental units
(57.6 versus home ownership (42.4 The majority of households are
families (55 and the average size of households is 2.38 persons.
Tukwila is a large player in the region's economy. Located near two large
metropolitan shipping centers (Port of Seattle and Port of Tacoma), three major
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highways (I -405, I -5 and SR 518) and two rail lines running through the Valley
bottom, Tukwila has become a major regional center of commerce. The State's
second largest shopping center combined with industrial, manufacturing, and
distribution facilities provide the majority of jobs within Tukwila. The daytime
population swells with a large and diverse employment sector consisting of
approximately 50,000 employees.
The City of Tukwila operates under a strong mayor /council form of government,
with the Mayor making up the executive branch, and members of the City
Council comprising the legislative branch. The seven council members are
responsible for overall policy and City law by passing ordinances and resolutions.
The Mayor is the Chief Executive Officer and is responsible for the
administration, public health, safety, and welfare of the City.
IV. Land Use and Development
Geographically, Tukwila is a relatively small area within an extensive valley
centered on the Green /Duwamish River drainage system. While the valley is
relatively flat, the upland plateau has rolling undulating topography. Tukwila's
residential neighborhoods consist of mix dense, small town residential areas and
newer suburban areas. Those residential neighborhoods are distinct geographic
areas within an urban setting that is becoming increasingly crowded with all the
challenges of urban living.
The Green /Duwamish River valley has evolved from an agricultural area to a
regional industrial and retail area. Land use along the river system is mostly
commercial and industrial with few residential areas. With the designation of the
Tukwila Urban Center and the Manufacturing Industrial Center in the Duwamish
Corridor, development along the shoreline is likely to evolve into more intensive
commercial and industrial uses. Intense development over the years has already
altered the natural environment along the river system.
A Land Use Zoning map is included in this Plan (Attachment 6). It conveys the
long -term plan for the primary-use character of the various City neighborhoods.
All areas of the City have distinct characters established many years ago. There
are few parcels of land that are remnants of the City's farming community but
most of the land is now suburban residential, commercial and industrial.
V. Hazard Identification and Vulnerability Analysis
This Section provides information on potential hazards whose impacts would go
beyond those considered "routine emergencies" within the City of Tukwila.
Hazards are separated into two major categories, Natural, and
8
Technological /Manmade events and will serve as a basis for local emergency
planning.
This hazard analysis uses High, Moderate and Low adjective descriptors for
each hazard's probability of occurrence and the City's vulnerability and the
potential impact of hazard to life and property. The risk rating is assigned on the
probability of a hazard occurring at certain intervals. A final risk rating is
assigned based on a subjective estimate of their combination, and the risk rating
will ultimately help focus the emergency management and hazard mitigation
programs on the incidents with the greatest potential risk.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Hazard Analysis Table
Probability of occurrence is an adjective (high, medium, low) of a particular
hazard impacting the City of Tukwila during a certain time interval. Probability is
based on a limited objective appraisal of a hazard's frequency from historical
data, trends, and other information provided by reliable sources. For the
purposes of this analysis, the criteria for high, moderate, and low probability are:
High Probability: The likelihood that a hazard will occur within a year.
Moderate Probability: The likelihood that a hazard will occur within the
next 2 -10 years.
Low Probability: The likelihood that a hazard event will occur with the
next 10 -100 years. Events occurring once every 100 -plus years are
considered as low probability.
The criteria for evaluating impacts are subjective. While there is some financial
data available for property damages, economic losses are more difficult to
ascertain. Additionally, the cost for injuries and fatalities are also difficult to
assess.
9
Np' 1uRpt.
HATAP
,e
DROUGHT
Definition of Hazard
Drought is a period of unusually dry weather that persists long enough to cause
serious problems such as crop damage, extreme fire hazard, and /or water supply
shortages. The severity of the drought depends upon the degree of moisture
deficiency, the duration, and the size of the affected area.
There are four different ways that drought can be defined.
Meteorological a measure of departure of precipitation from normal.
Due to climatic differences, what might be considered a drought in one
location of the country may not be a drought in another location.
Agricultural refers to a situation where the amount of moisture in the
soil no longer meets the needs of a particular crop.
Hydrological occurs when surface and subsurface water supplies are
below normal.
Socioeconomic refers to the situation that occurs when physical water
shortages begin to affect people.
History of Hazard as it Affects the City of Tukwila
Historically, drought has not been a major concern for the Tukwila area. The
Tukwila area experiences water shortages and low flow on rivers and streams
every few years. A severe reduction in the flow of rivers and streams in the area
could cause serious damage to the aquatic life in the wetland areas. In 2001
rainfall for western Washington fell to 30% below normal. The National Weather
Service reports that 2000 -2001 had been the driest winter in Washington since
1976 -77. It is also one of the five driest in the past 100 years. In 1992, low
flows in area rivers threatened fall salmon spawning. Stream flows were between
30 and 70 percent of normal.
Hazard Identification
Nearly all areas of Tukwila are vulnerable to the effects of drought. Water
utilities are aware of this problem. They continuously monitor ground water
levels, and will implement water conservation measures as necessary.
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Highline water district intertie
Water district 75 intertie
Water district #75 intertie
Vulnerability Analysis
The agricultural and farming community would feel the greatest impact of a
moderate drought. Farming and agriculture in the greater Tukwila area are
comprised of small farms that produce fruit and vegetables. Several nurseries
are also located in the area. Annual and perennial crop losses, damage to crop
quality, and increased insect infestation would affect the farming community. A
moderate drought would also force the added use of the community water
system due to the diminished water supplies. This reliance would create a
financial strain on the farming and agricultural community, causing higher prices
in the marketplace.
A lengthy drought combined with extremely hot weather would create cause for
concern. The farming and agricultural community would face financial hardship
if they had to rely solely on the municipal water supply to irrigate their crops and
provide water for their animals.
Severe problems could conceivably occur in the event of water shortages
requiring rationing. Many businesses, small and large alike are high water
consumers. These businesses require large amounts of water in their daily
operations. A severe drought creating water rationing could force these
businesses to cut back on operations until water levels improve. The Toss to
manufactures and sellers of recreational equipment and related activities would
impact the local recreation and tourism industry. Financial losses and the layoff
of workers could result.
Fires from grass and brush with reduced moisture content would spread rapidly
and pose a threat not only to farm crops and wildlife, but also to homes and
businesses near susceptible wild land /urban interface areas. There may also be a
reduction in water available to fight fires. A major urban fire requiring large
volumes of water could have significant impact on local water supplies during a
drought.
Conclusion
The most significant vulnerability in Tukwila from a prolonged period of dry
weather is the elevation of fire threat in the land -urban interface along I -5 on the
west.
Because the Tukwila area is serviced by a commercial water system supplied by
City- purchased water and is backed with subsequent interties, it is unlikely that a
moderate drought would create an economic concern for the area. Such an
event in the Tukwila area would not likely be a threat to human life.
12
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
4 Lodi Prob Low Probability Low Probability
4 f =o w Impact)
(Moderate Impact) (High Impact)
Drought Probability and Impact Analysis
13
EARTHQUAKE
Definition of Hazard
Earthquakes are defined as the sudden release of energy occurring from the
collision or shifting of crustal plates on the earth's surface or from the fracture of
stressed rock formations in that crust. This release of energy results in the earth
shaking, rocking, rolling, jarring and jolting; having the potential to cause
minimal to great damage in the Puget Sound area. Earthquakes are measured
by units of magnitude, which is a logarithmic measure of earthquake size. This
means that at the same distance from the earthquake, the shaking will be 10
times as large during a magnitude 5 earthquake as it would during a magnitude
4 earthquake.
History of Hazard as it Affects the City of Tukwila
Western Washington and the Tukwila area have a long history of documented
earthquake activity. Tukwila is geographically located in an area known as the
Pacific Ring of Fire. The same geologic events that result in the creation of
volcanoes and volcanic events may also generate notable earthquakes. Western
Washington is framed by the Pacific, North American, and Juan de Fuca plates,
with a significant amount of active fault lines identified in the Puget Sound area.
All of these have been the cause of earthquakes in history, with the most notable
recent earthquakes being the 1949 magnitude 7.1 Olympia earthquake, which
caused over $100 million in damages and killed 8 people; the 1965 magnitude
6.5 Seattle- Tacoma earthquake which caused over $50 million in damages and
killed 7 people; and the 1999 magnitude 5.5 Satsop earthquake. The most
recent 6.5 magnitude Nisqually earthquake caused over $2 billion damages and
injured over 400 people in Western Washington. In Tukwila, a few commercial
buildings received significant structural damages. Annually, hundreds of
earthquakes occur in Washington, most of which go unnoticed (less than
magnitude 2.5).
Hazard Identification
The earth is divided into three main layers a hard outer crust, a soft middle
layer and a central core. The crust is broken into massive irregular pieces called
"plates which have been moving very slowly over the earth's surface for billions
of years, driven by energy deep within the earth. This movement has shaped
the physical features of the earth its mountains, valleys, plains, and plateaus.
As these plates move, stresses are built up and periodically release energy in
areas where the plates come into contact with each other.
14
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(Oceanic) Plate'` 0
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(Continental)
Plate
p Deep Eartiquakes (40 miles below the Earth's surface) are within the subducthg
oceanic plate as it bends beneath tie continental plate. The largest deep
Ncrtrwest earthquakes known were in 1949 (M 7.t), 1965 (M 6.5), and 2001 (M 6.8).
Shallow earthquakes (less than 15 miles deep) are caused by faults In the
North American Continent. The Seattle faultpreduced a shallow magnitude 7+
earthquake 1,100 years ago. Otter magnitude 7+ earthquakes occurred h
1872, 918, and 1946.
Subductbn Earthqkes huge that resultwhen tie boundary between tie
oc and ca dt enua are tal P later r res h 1700 the most recent Casc adla Subduct
Zane eartiquake sent a tsunami as far a s Japan.
421.16. Mt. St HelenslOtherCascade Volcanos
There are three technically distinct types of earthquakes that have the ability to
generate powerful damaging motion in the greater Puget Sound area:
Benioff Zone /Interp /ate (Deep) earthquakes
These earthquakes occur at depths of 15 to 60 miles from the subducting Juan
de Fuca plate. The Olympia, Seattle- Tacoma, Satsop and Nisqually earthquakes
are all examples of Benioff Zone earthquakes. They usually do not exceed
magnitudes of 7.5, are 15 -40 seconds in duration, have normal faulting with no
large aftershocks. These earthquakes are more frequent than subduction zone
earthquakes, typically occurring every 30 or so years.
15
Subduction Zone Events
These earthquakes occur along the interface between tectonic plates, generated
from the collision of the Juan de Fuca, Pacific, and North American plates. This
area is also known as the Cascadia Subduction Zone, and it ranges from
southern British Columbia to Northern California. These earthquakes are
considered great magnitude events and may reach 8.0 -9.0 on the Richter scale.
Researchers say the stresses they observe off the coast of Washington could
cause an earthquake measuring up to 9.5. The duration of shaking could last up
to 3 minutes. A subduction zone earthquake may also generate tsunamis. The
last known subduction earthquake in the Puget Sound area occurred in 1700.
Geologic evidence indicates that these great earthquakes may have occurred at
least seven times in the last 3,500 years, suggesting a return time of 400 -600
years.
Shallow Crustal Earthquakes
The largest known historic earthquake in Washington or Oregon occurred in
1872 in the North Cascades. This earthquake had an estimated magnitude of 7.4
and was followed by many aftershocks. It was probably at a depth of 10 miles or
less within the continental crust. Many other crustal sources in Washington and
Oregon could also produce damaging earthquakes. Recent studies have found
geologic evidence for large shallow earthquakes 1,100 years ago within the
central Puget Basin. Massive block landslides into Lake Washington, marsh
subsidence and tsunami deposits at West Point in Seattle, tsunami deposits at
Cultus Bay on Whidbey Island, and large rock avalanches on the southeastern
Olympic Peninsula have all been dated to approximately 1,100 years ago.
Earthquake energy is released on the earth's surface primarily through faults. A
fault is a fracture in the crust of the earth along which rocks on one side have
moved relative to those on the other side. Most faults are the result of repeated
displacements over a long period of time. A fault trace is the line on the earth's
surface defining the fault. Fault rupture almost always follows preexisting faults,
which are zones of weakness. Rupture may occur suddenly during an earthquake
or slowly in the form of fault creep. Sudden displacements are more damaging to
structures because they are accompanied by shaking. The following is a map of
major earthquake fault zones in the Puget Sound region.
16
Major Fault Zones
in the Puget sound
ieto ria• t A O
Mt. Vernon
sw� i' 4 't� 4f. Q
q. .4: N. Whidbey Is. Fault
e
Port Aogel.es `-1. 1
cs'
t i t!! Everett
S. Whidbey Is. Fault
a
a, /J Seattle Fault
3
Bremerton 1 1 Tukwila
0 i aea m a
Y
if
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-I- 47
L
Centralia IS 1 1 1 1 1 1
U 50 K
123 122
In addition to the different types of earthquakes, geologic factors affect how the
Tukwila area will fare during an earthquake. The valley is composed of soft
materials such as mud, artificial fill and layers of sand and clay that can amplify
ground shaking and make overall damage more intense. Soft soils tend to liquefy
during an earthquake creating a condition known as "liquefaction This
condition can result in local areas experiencing severe damage, especially where
the ground fails (or liquefies) under buildings, pipelines or bridges. Landslides
and rock falls may be triggered on steep slopes.
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Vulnerability Analysis
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1:t-- 'rx,Vy
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ar t 'n r f .,t
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Tom Reese The Seattle Times
A worker inspects the damage from an earthquake triggered
mudslide that flowed into Cedar River in Renton's Maple
Valley.
Any building or structure built on land that slides in an earthquake could be
destroyed, creating an extreme hazard for those buildings or structures on the
hillsides above the valley floor. Landslides could also pose a threat to
transportation routes, preventing emergency vehicles from responding in an
earthquake disaster. Additionally disruption of water, sewer, power and
communication lines would be likely.
"u
a_
r t 1+! a y
y; r
3 v 'fit^A,` a
Steve Bloom The Associated Press
A sidewalk in Olympia that buckled from the Nisqually quake.
Transportation and communication would be limited or inaccessible. Major
transportation lifelines are built on liquefaction prone soils and hillsides that
could be destroyed as a result of an earthquake. Bridges may be damaged or
need structural assessment resulting in road closures. Assessment of bridges,
overpasses and roadways may be delayed, creating a potential for injuries.
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Downed utility lines could cause more problems for transportation as well as the
loss of communication and power.
Fire, a hazard in itself, frequently accompanies earthquakes. Fire usually occurs
as a result of damaged electrical equipment, broken gas lines, fuel spills,
disrupted heating equipment or any combination thereof. These fires can break
out in multiple locations in a short period of time following an earthquake,
quickly causing firefighting resources to be overextended. Additional strain on
firefighting capabilities could be caused by transportation route interruptions and
broken waterlines, which could make firefighting challenging.
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�M a re
140 af:,',11ti 4:' '`ir. lir **4. 41,*m
L r 7 :4 .0.6 :le
i6 1(.
!•r It i s
"Masonry /'-mss 4 4 1 S
Damage in Seattle after the 2001 Nisqually earthquake
Damage to existing structures in the area could be significant, with older brick
buildings and tilt -up warehouses potentially being the most susceptible. Because
the valley contains a large concentration of older buildings situated on soil prone
to liquefaction, it is likely that this area would be heavily damaged in the event of
an earthquake. Facilities such as schools and community buildings are of
concern as well, due to the potential for high loss of life.
The Howard Hanson Dam has a significant effect on the Duwamish /Green River.
The structural issues recently discovered at the Dam poses a significant risk for
flooding throughout the entire Green River Valley Community. An earthquake
could potentially compound problems at the Dam and could create a serious
flood hazard to downstream communities.
The time that an earthquake occurs significantly determines the impact of the
quake. The most significant effect of time relates to the potential for human
casualties. Experts believe that casualties would be greatest during hours of
heavy vehicular traffic and when large numbers of people are in concentrated
19
areas such as business and government districts, places of commerce and
schools.
Conclusion
The effects of a major earthquake in the Tukwila area have the potential to be
catastrophic. Potentially, there could be hundreds of fatalities and thousands left
homeless. Damage to buildings and structures could be in the millions of dollars.
Transportation and communication could be disrupted from flooding, landslides,
structure damage, and downed lines.
Building codes continue to be strengthened to address potential effects of
earthquakes on structures. However, because of an earthquake's potential for
catastrophic human and economic consequences, it is incumbent upon the City
to continue taking appropriate actions that mitigate against its severity by
enforcement of codes, implementing improved building standards, and by
educating City employees, residents and businesses. Public awareness
programs, school staff and student community "Drop, Cover and Hold" training
and drills, Community Emergency Response Team (C.E.R.T) education and
training, and community outreach on what to do before, during and after an
earthquake are preparedness measures that should be incorporated into the
mitigation strategy.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (Low Impact)
Earthquake Probability and Impact Analysis
20
FLOODING
Definition of Hazard
A flood is an unusually large flow or rise of water, especially over land not
usually covered with water.
Of all possible natural hazards, Tukwila is most prone to flooding. There are two
types of flooding which could conceivably occur in this area:
Riverine flooding: Floods which occur because of prolonged rain,
melting snow or both. The first element leading to a potential Riverine
flood is a heavy, fresh snow in the mountains. If a weather front with
warm winds, usually from the southeast, and heavy rainfall follow the
snow before it has a chance to settle and solidify, a flood potential exists.
Flash flooding and surface flooding: Several factors contribute to
flash flooding. The two key elements are rainfall intensity and duration.
Topography, soil conditions, urbanization and ground cover also play
important roles. Flash flooding occurs within a few minutes to a few hours
of excessive rainfall, a dam or levee failure, or a sudden release of water
held by an ice or log jam. In addition, localized surface or "urban"
flooding occurs as the result of drainage systems that are incapable of
carrying exceptional volumes of snowmelt and heavy rain runoff.
The first flooding type is the most likely to occur, with the second being possible
as the result of dam or other flood control system failure, such as the Green
River levee system.
History of Hazard
The Green River Valley was historically inundated by large floods until the
construction of the Howard A. Hanson Dam. Since operation commenced in
1962, the Dam, together with the construction of a levee systems along the
Green River, have prevented significant flooding and limited flood damages.
.1 4 IY ms
W41 1 1, 7 A
r-
Green River Valley flooding in the 1930's
21
There have been five Presidential declarations for flood disasters in King County
since 1970, with the most recent and memorable floods in the vicinity being the
ones that occurred in November December 1990, the flood of February 1996,
and the flood of 1997. All of these floods caused severe damage to several City
parks and roadways. The rainfall was less intense during the recent 2001 New
Year's storm. The most significant difference between the 1996 and 2001 events
was the combination of heavy rainfall and melting of significant snow
accumulations at low elevations in the most heavily populated areas of the
county during the New Year's storm. This combination produced flooding and
large volumes of runoff in the urban and suburban creek basins.
In November 2006, the prolonged rain events damaged two sections of the
Green River Levee in Tukwila. The damage was on the west side of the River
(Sites 3 and 5). Site 3 is located southwest intersection of West Valley Highway
and South 180 Street and Site 5 is southeast intersection of South 180 and
Andover Park West. The total cost to repair the two sections was approximately
$6 million dollars. The damages in Tukwila represent two of more than 50
levees damaged in the region.
Following a record high level of water behind the Howard Hanson Dam in
January 2009, the U. S. Corps of Engineers (USACE) discovered problems with
the Dam that has the potential to cause serious flooding in the Green River
Valley communities of Auburn, Kent, Renton, Tukwila and Seattle. To date,
USACE has spent nearly $10 million dollars constructing a temporary seepage
barrier and improving the drainage systems at the Dam. The downstream
communities have also spent millions of dollars in flood fighting and flood
protection activities.
Hazard Identification
Tukwila experiences some degree of flooding almost every year. This event is
most likely to occur during "flood season" between the months of November and
March when rains are the heaviest. The major problems have been lowland
flooding and road closures as a result of standing water. Surface flooding is most
likely caused by slow- moving thunderstorms or by heavy rains associated with
spring or early summer storm systems or combined with Riverine flooding. A
flash flood is likely to occur as a result of some form of flood control system
failure.
A failure of the levee system that has been built up and guards the banks of the
Green River would also produce flash flooding. Since the banks of the Green
River are built up several feet higher than the surrounding area, damage to
these banks or levees would quickly inundate the adjacent areas and spread
throughout the lower, valley floor.
22
Vulnerability Analysis
A very common type of flooding in the lowland areas is due to the frequent two
to three day storm. This flooding normally creates transportation difficulties like
slippery roadways and poor visibility, increasing the likelihood of traffic accidents
and a slowdown in emergency response. Basement flooding and mudslides are
also likely occurrences. A storm lasting longer would worsen the effects
considerably. Possibilities include: serious property damage, disruption of utility
systems, inaccessibility of the valley area via normal traffic routes, health and
environmental hazards as a result of sewer and septic system backups and
storage of hazardous substances in area businesses, displacement of those living
and working in the affected area, and economic disaster for businesses and
citizens alike.
The Howard Hanson Dam is located approximately 40 miles upstream from
Tukwila on the Green River. In the event of dam failure, the riverbanks in the
Tukwila area would reach their peak (bank level elevation approximately 39 feet)
in about 8 hours with the entire Green River Valley inundated with 8 15 feet of
water within 24 -36 hours.
:7,..70: r max
0
Howard Hanson Dam
Shortly after the discovery of two depressions on the right abutment of the Dam,
USACE Engineers quickly excavated the sites, installed monitoring equipment and
conducted tests. They have isolated the cause of the two depressions, but they
are still concerned with the seepage within the abutment. USACE has
23
constructed a temporary seepage barrier wall and has improved the right
abutment drainage system but until seepage concerns are permanently
addressed USACE has placed restrictions on the pool elevation. The restricted
flood storage means that if heavy and prolonged rain occurs, USACE would
release water into the Green River at much higher flow rates for longer periods
of time. This situation creates a significant risk of flooding for Tukwila residents,
businesses, and properties along the Green River. A City map depicting the
potential flood affected areas is provided as part of this Plan at Attachment 7.
Should a major flood event occur, the temporary restrictions on pool elevation
could cause the following scenarios:
Overtopping river flows that are higher than the existing or raised top
of level or riverbank. on the levee system.
Debris Flow upstream logs, trees, buildings, etc. that could jeopardize
the integrity of the levee, riverbank, bridges or critical infrastructure such
as telecommunications cables, and utilities.
Levee /bank degradation high river flows could cause scour or erosion
that lead to piping, boils or seepage through the levee /bank.
Levee failure unexpected break in a levee due to undetected structural
defects. The water pressure is so great that it will scour at the levee and
the ground and quickly create a breach 100' or more in width.
s-
Nom,
Catastrophic Levee Failure
24
Conclusion
The permanent solution to fix the seepage problem at the Howard Hanson Dam is a
significant undertaking. It will cost millions of dollars and will take a few flood
seasons to complete the massive project. In the mean time, the Green River Valley
community is faced with the potential loss of life and economic disaster should any
of the scenarios occur.
If heavy and prolonged rain occurs during the flood season, many homes and
businesses in the Valley including parts of Auburn, Kent, Renton, South Seattle, and
Tukwila could be flooded. Evacuations in some communities are possible, key
transportation routes and transit services could be disrupted, power outages and
sewage backups are possible, critical communications could be damaged and public
safety assets would be strained.
The entire Tukwila community must continue to work on preparedness measures
and implement prudent and responsible flood protection mitigation activities. The
City should continue to participate in the National Flood Insurance Program and
residents as well as businesses should consider purchasing flood insurance.
a
Tukwila Flood Mitigation Project e November 2009
High Probability High Probability
tY 9 ty
(Low Impact) (Moderate Impact)
Moderate Probability Moderate Probability Moderate Probability (High
(Low Impact) (Moderate Impact) Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Flood Probability and Impact Analysis
25
LANDSLIDE
Definition of Hazard
The term landslide refers to the downward movement of masses of rock and
soil. Landslides in this area are for the most part masses of soil ranging in
volume from just a few feet, to many yards. The rate of travel of a slide can
range from a few inches per month to many feet per second, depending on
slope, material and water content. Landslides can be initiated by storms,
earthquakes, fires, erosion, volcanic eruptions and by human modification of the
land.
History of Hazard
Tukwila's topography has made some areas prone to landslides. In recent years,
there have been incidents of property damages from landslides. Heavy
snowstorms in December 1996 and January 1997 were followed by a warming
trend that caused quick melting, runoff, and flooding. This period was then
followed by rain. This led to over 100 slides in King County over the subsequent
two -month period.
Most recently, during the December 2008 January 2009 severe winter storm, a
major landslide occurred on a 120 -feet high steep bluff above the west side of
Interurban Avenue, displacing approximately 100 feet of jersey barriers and
blocking traffic for several hours. Fortunately, no injuries occurred but the City
incurred several thousand dollars in clean -up and debris removal costs and
overtime for Tukwila Police, Fire and Public Works Department personnel.
Hazard Identification
Conditions which lead to soil instability and sliding include steep slopes, water
saturation and deep frost. Building and road construction are also a contributing
factor to landslides as they often undermine or increase the slopes of otherwise
stable soil.
Landslide hazard areas include areas potentially subject to landslides based on
combination of geologic, topographic, and hydrologic factors. They include any
areas susceptible because of any combination of bedrock, soil, slope (gradient),
slope aspect, structure, hydrology, or other factors.
26
Features that may indicate Landslides include:
Ancillary structures such as decks and patios tilting and /or moving relative
to the main house.
Tilting or cracking of concrete floors and foundations.
Leaning telephone poles, trees, retaining walls or fences.
Rapid increase or decrease in creek water level.
Sticking doors and windows, and visible open spaces indicating jambs and
frames out of plumb.
The following are some measures that can be taken to avoid landslide
hazards:
Reduce surface erosion, keep drains and culverts clear.
Maintain and improve vegetation; trees and shrubs provide root strength
to hold the soil in place and help dewater the slope. If such vegetation is
removed, root strength will be gone within 2 to 12 years and will not be
easily restored.
Protect bluff from surface erosion; apply erosion mats, plastic sheeting, or
other erosion control material where vegetation will not take hold.
The hillsides on the east and west sides of the Green River Valley area are
particularly vulnerable to landslide activity. Because there are many structures
built along these hillsides more lives are endangered and there is greater
potential for damage in the event of a major occurrence.
Vulnerability Analysis
Landslides can cause disruption of roads, water, sewer, gas, electric and phone
lines, as well as serious damage to public and private property. Injuries, loss of
life and property loss could occur.
International Building Code and Tukwila Land Use Zoning Code regulations
address impacts of potential development in landslide areas.
27
Conclusion
Geologically hazardous areas include areas susceptible to erosion, sliding,
earthquake, or other geologic events. They pose a threat to the health and
safety of citizens when incompatible commercial, residential, or industrial
development is sited in areas of significant hazard. Some geologic hazards can
be reduced or mitigated by engineering, design, or modified construction or
mining practices so that risks to health and safety are acceptable. When
technology cannot reduce risks to acceptable levels, building in geologically
hazardous areas must be avoided.
The effects of landslides could be mitigated by considering and enforcing
sensitive area and land use ordinances.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Proba ib lib lity Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Landslide Probability and Impact Analysis
28
SNOW /ICE STORM
Definition of Hazard
This type of hazard is an atmospheric disturbance characterized by strong wind
and is usually accompanied by rain, snow, sleet, hail, and often thunder or
lightning.
Snowstorms or blizzards, are storms accompanied usually by high winds and /or
snow drifts. These storms occur occasionally in the area.
Hailstorms occur when freezing water in thunderstorm type clouds accumulates
in layers around an icy core. Wind added to hail may batter crops, structures
and transportation systems.
An ice storm occurs when rain falls out of warm moist upper layer of atmosphere
into a below freezing, drier layer near the ground. The rain freezes on contact
with the cold ground and accumulates on exposed surfaces. If this is
accompanied by wind, damage can occur to trees and utility wires.
History of Hazard
The Tukwila area like the rest of the Puget Sound area is known for its moderate
climate. Snowfall rarely exceeds ten inches in an entire season. The snow that
does fall seldom remains on the ground more than a couple of days.
Chances for accumulation of snow in the event of a single severe weather front
following another are historically minimal. However, since 1985 and most
recently in January 2004 the area has experienced major winter storms that have
created significant hazards and damages totaling millions of dollars.
Hazard Identification
All areas of Tukwila are subject to the effects of these hazards. In particular,
people, power lines, transportation routes and structures are vulnerable to the
effects of cold, weight of the snow, winds and falling trees. Snow, like other
hazards, does not have the same impact on all areas. The depth of the snow as
well as the temperature and location of the snowfall are major factors in
determining the degree of hazard that is presented to the area.
Building codes continue to be strengthened to address potential effects of snow
and ice storms on the structural integrity of buildings.
29
Vulnerability Analysis
The Tukwila area has hills on either side of the valley. The hillsides and infrequency
of snowstorms make such storms dangerous and difficult to deal with. Major
transportation difficulties usually occur as the result of even a minimal snowfall.
Heavy snowfalls create dangerous, inaccessible roads, poor visibility, and traffic
accidents. Drivers in the area have little opportunity to gain experience driving on
snow covered streets, with problems amplified by lack of proper tires and chains to
mitigate the hazardous driving conditions. Snow removal operations are often
affected by lack of manpower and equipment. Emergency response by fire, police,
and public works personnel is often hampered by ice and snow on roads that are
sometimes inaccessible and dangerous.
Most of the structural damage resulting from heavy snowfalls is roof and structure
collapse, with downed power lines and trees providing major difficulties for repair
crews and residents. Elderly and vulnerable people often find themselves isolated in
these situations and have difficulty obtaining food, medicines and other necessities.
Additionally, dangerous situations occur as the result of power outages that result in
the lack of heat for many areas. Efforts made to create makeshift heating and
lighting often lead to fires, explosions and asphyxiation.
Ice and freezing rain, which frequently hits Tukwila create similar difficulties. Ice
and freezing rain are not as visible as snow, and therefore intensify the driving and
transportation hazards. Freezing conditions are a common occurrence from
November to February. These conditions can exist as the result of a simple rain with
temperatures dropping below the freezing level overnight creating an "unknown"
hazard to the community as morning activities begin.
Conclusion
Snow and ice storms can strike the area with little warning. These incidents occur
infrequently and as a result, the effects of them are often enhanced by the public's
inexperience dealing with the challenges posed by them.
The most significant effect of these storms is structural collapse, interruption of
utilities and the disruption of transportation routes, injuries, hardship and economic
loss.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Snow /Ice Storm Probability and Impact Analysis
30
URBAN FIRE
Definition of Hazard
Urban Fires in cities or towns primarily involve buildings with potential for spread
to adjoining structures. Additional risks can be found in the numerous modes of
transportation that can potentially intermingle within a given jurisdiction.
Although the statistics show a decline in fire casualty rates in recent years, the
U.S. rate remains much higher than the reported fire death and damage rates for
Australia, Japan, and most of the Western European countries.
The urban fire hazard in the City of Tukwila involves areas where single family
homes, multi family occupancies, multi -unit transient residential occupancies
and /or business facilities are clustered close together, increasing the possibility of
rapid fire spread to another structure. Other areas are characterized by adjoining
buildings. Adjoining buildings are found in the commercial or industrial sectors of
the city or include other closely spaced wood framed structures. Not to be
overlooked are the numerous transportation modes and routes that intersect the
city's landscape. Fire responses can and have been generated to all modes of
private and commercial transportation on either of two interstate freeways and
numerous state highways and local surface streets. The city of Tukwila hosts a
major North /South rail line. Transportation of cargo is the primary use for this
line, however, Amtrak and mass transportation commuter rail locomotives share
this same stretch of track. The newly completed Sound Transit Light Rail system
spans the length of the city, and poses the difficult threat of fires in mass
transportation vehicles on elevated structures. Portions of Boeing Field (King
County Airport) rest with the borders of the city. This airfield generates
continuous private and commercial air traffic, with many annual take offs and
landings generated, and much of these taking place above the city's airspace.
Although private and commercial vessel traffic on the Duwamish /Green river
system is somewhat limited within the city's jurisdiction, consideration must be
given to the added risk of response to fires involving vessels during transit
through the jurisdiction. As a transportation hub, the City of Tukwila's risk or
exposure to fires involving some form of transportation nearly equals the
potential risk associated with structural response.
Hazard Identification
Fire has many causes which can range from faulty wiring to improper storage
and handling of flammables, illegal explosive devices, and arson. Fires range
from small fires which can be easily managed to a conflagration. A conflagration
is a fire that expands uncontrollably beyond its original source area to engulf
31
adjoining regions. Wind, extremely dry or hazardous weather conditions and
explosions are usually the contributing elements behind a conflagration.
There are certain sectors of the city and populations which are more vulnerable
to fire than others. Those areas which have a high risk population density
present a high risk for fire simply due to increased exposure and probability.
Those same areas can also pose the threat of high casualty rates for the same
reasons.
A large urban fire puts a tremendous strain on many of the operating
departments of the community. The fire service needs all available firefighters to
control the blaze and yet must continue to meet normal demands for service;
law enforcement provides for evacuation activities, traffic and crowd control;
public works is tasked with supplying a continuous supply of critical utilities
necessary to manage the incident.
Zone resources may be asked for assistance in one form or another, resulting in
reduced response capabilities in the supporting jurisdictions.
Vulnerability Analysis
The housing of low income persons is often in older structures which do not
conform to modern building and fire codes and do not contain fire detection
devices. These structures are also prone to faulty electrical, heating and other
utility systems due to age and lack of proper maintenance. Many of these older
structures were constructed in very close proximity to one another, enabling fire
to spread rapidly from one structure to another. Older apartment buildings and
hotels also face increased risk of rapid fire spread due to inadequate firewall
protection and the lack of fire detection and sprinkler systems.
Some of the newer residential structures and hotels, though still susceptible to
high population risk, are not as vulnerable to fire as are older structures. These
structures were designed and built to include fire resistive features which
conform to modern fire and building codes. Fire detection and /or extinguishing
systems were also installed in these buildings at the time of construction.
Though a major fire could certainly occur in these structures, the likelihood of its
spreading to adjoining structures or units before it can be brought under control
is significantly reduced.
Commercial, industrial and multi family fires present their own unique hazards.
Some newer structures, like residential occupancies, are built with fire resistive
construction and fire detection and /or sprinkler systems (in buildings over 10,000
sq. ft.) thereby reducing the risk of major fires. Older structures and single
32
family dwellings however, share many of the same problems as older housing
and are at a greater risk of fire.
Several commercial and industrial occupancies within Tukwila store and use
hazardous materials. The storage and use of these materials not only increases
the risk of fire, but also pose a significant threat to firefighters and the
community if the material should become involved in a fire.
A sizable earthquake in Tukwila could damage any or all of the city's main water
supplies, transmission lines, and /or feeder lines. Without adequate water
reserves, automatic sprinkler protection would fail and firefighters would be
unable to attack a wide fire front. In such a setting, a small fire could easily
spread beyond control.
Conclusions
The threat of a large scale urban fire is limited in Tukwila except for the
introduction of an outside event such as an earthquake or hazardous materials
incident. The number of commercial and industrial fires has been controlled in
recent years due to the annual fire inspections performed by fire department
personnel. These inspections not only identify potential problems, they also
provide an opportunity for business owners and workers to be more aware of fire
prevention through education provided at the time of inspection. Despite the
best effort, however, some fires still occur.
The science and art-form of Arson Investigation has also been a significant factor
in the reduction of urban fires. Investigators and fire crews are working together
to convict and or deter more arsonists than ever before.
Despite the efforts of the fire service, aging buildings and acts intentionally or
unintentionally made by people will contribute to the incidents of burning
buildings in the Tukwila area.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Urban Fire Probability and Impact Analysis
33
VOLCANIC ERUPTION
Definition of Hazard
A volcano is a vent in the earth's crust through which molten rock (magma), rock
fragments, gases, and ashes are ejected from the earth's interior.
A volcano is created when magma erupts onto the surface of the earth.
Volcanoes take many forms according to the chemical composition of their
magma and the conditions in which the magma is erupted. When magma is
erupted it is referred to as lava. Some lava known as 'basalts' is hot and fluid.
Opposite of basalts are 'rhyolites', which are characterized by their inability to
flow freely, erupt explosively or form steep domes. Midway in between are
'andesites' which are thick, flow slowly, and are mildly explosive.
History of Hazard
On May 18, 1980, Mt. St. Helens erupted with explosive force killing 57 people.
Heavy ash fall blanketed much of Eastern Washington into Northern Idaho and
Western Montana. Subsequent eruptions on May 25 and June 12, similarly
affected Western Washington and
Portland, Oregon, although to a
lesser degree. Cascade Eruptions During The Past 4,000 Years
f I Baker
Mount Rainier at 4393 meters Gla er Pk. I
(14,410 feet) the highest peak in St' 3;
Helens L
ry r ror r p
the Cascade Range is a dormant Hood Adams r L
volcano whose load of glacier ice Jefferson
exceeds that of any other mountain w Three Sisters I I I
It Newberry S: I
in the conterminous United States. Crater Lake I I
This tremendous rock and ice mass, g Medicine Lake I .R
g
Shasta I AR A2 )2 i
poses a variety of geologic hazards. n,,,- Lassen
The written history of Mount Rainier 4000 2000 200
encompasses the period since Years Ago
about A.D. 1820, during which time I uSGs I Mye�U ,CVO, Modfied from CVO, ,99, USGS o, -Fk Report 94_
one or two small eruptions, several
small debris avalanches, and many Recent eruptions in the Cascades (USGS)
small lahars (debris flows originating
on a volcano) have occurred.
34
Hazard Identification
A volcano is commonly said to be "active" when it is in the process of erupting
and "dormant when it is not. Scientists, however, usually use the term "active"
to refer to any volcano that has erupted in historic time or is seismically or
geothermally active. By this definition Mounts Rainier, Baker, Hood and St.
Helens are active volcanoes.
,,,,e-
Enlptlon Cldt fl ~4" i r,� 1...--,,,4',.. :r Prevailing wind
a
Ash (Tephra) Fail
Eruption Column
Landslide
Acid Rain Bombs f (Debris Avalanche)
y'
,'Veti 'Pyroclastkk Flow
Lava Dome Collapse Lava Dome
Pyroclasiia F10W 4
l
f t Fumaroles
Lunar (Mud Or Dabric Flow} I
4' r r Ground
;;fi Water
:Silica (aiOG) Magma '4
Content Types i -r .t
1 OC}M
z
F#hy lEte Crack
Decite ..w
Atl agma
p Mrt4IT ,�4 i
re _at
L''aic;3rrr.ir?s Firelthic. e a wide variety of Daiwa! hazards Hull call kV per iro aref dp:stroy pr_iperty. This
sit'ttptined sk'oich shows a liDi aPa ry pical 01 t!}osa found in Ma Wcstclt "r U;iirtat7 S &Jros and Alaska, but nianv
all these httzerdds also pose risks of either veiicalloes, such as Mose pi 1 fr7iver1'. Some hazards, rucf as
fahats =ir,d landslides, can .DE:cut gran when a 4wJra.no is nor erupting_ (,Harolds arid ter rrts in th s diagram
arc h iqt Fighrad in bold n icro they are di.cussod in rlra toxt ibelaur
Volcanoes usually exhibit some warning signs before erupting. Most of these
warnings can only be detected by instruments; therefore, it is not surprising that
stories are told about volcanoes erupting without warning. Explosions caused by
heated material coming into contact with ground water, and involving no new
magma, do happen without warning. They are less spectacular than magmatic
eruptions, but can still be violent and release great mud flows.
The basic hazards of a volcanic eruption are:
Steam and gas explosions: Explosions of steam or other gases,
containing pulverized rock particles in suspension, fragments of older
rocks from pea sized to hundreds of tons, newly erupted hot lava bombs,
and a shock wave that may extend for several miles. Steam explosions
can occur anytime hot material comes in contact with water, ice, or snow.
No eruptive activity is necessary for this to occur.
Volcanic gases: Pockets or clouds of toxic gases kill with chemical
poisons, internal or external burns, or asphyxiation. As an example,
carbon dioxide is heavier than air, and may collect in low areas near active
and inactive volcanoes. Gases mixed with ash make up the eruptive
cloud, the 'smoke' of the volcano.
Tephra and volcanic ash: Ash fall normally accompanies the eruptions
of andesitic volcanoes. The lava in these volcanoes is so thick and
charged with gases that it explodes into ash rather than flow.
Ash is harsh, acidic, gritty, smelly, and thoroughly unpleasant. Ash can
cause respiratory problems even to the point of causing death. When ash
combines with rain, sulphur dioxide combines with water to form diluted
sulfuric acid that may cause burns to skin, eyes and mucous membranes.
Hydrochloric acid rains have also been reported. Acid rains may affect
water supplies, burn foliage, strip paint, corrode machinery, and dissolve
fabric.
Heavy ash fall blots out light, which can cause a heavy demand on power
supplies, leading to possible power failure. Ash clogs water courses and
machinery of all kinds. It causes electrical short circuits, and drifts into all
transportation routes. It is slippery and its weight can cause structural
collapse. Because it is easily carried by air current, it remains a hazard
long after an eruption.
Volcanic landslides and glacial outbursts floods: Avalanches of
glacial ice or rocks may be set in motion by explosions, earthquakes or
heat induced melting of ice and snow. The latter may also create a mud
36
flow. Earthquakes may release meltwater or a glacial outburst flood from
behind an ice dam or within a glacier. This is a common event and can
occur without apparent cause. Most cascade outburst floods have
occurred between August and November, but they may happen at any
time of the year.
7
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EXPLANATION
Small lahars with recurrence
interval <100 years (Case 3)
Mod°rnte lahars with recurrence
interval 100 -500 y ears (Case 2)
1 I 1 ar lahars with recurrence
interval 500 -1000 y ears (Case 1) PacicwoOr9
Area most likelyio be affected by �a
lava (lows and pyu eIastie (lo R°"`
K�/l Post -lahar sedimentation Randle _.r_
CntYli47• Lana
y 0 5 l MILES
RUA -L ahr !'v..� 1
__„T ,y 5 1'0 KILOMETERS
Volcano hazards from Mount Rainier, Washington: Pyroclastic -flow hazard zone
and inundation zones for Case I, II, and III lahars
Lahars: Mud and debris flows composed of melt water, rain, ash, pumice,
rock and anything else in the way, may be released by explosions, heavy
rains, or earthquakes. This danger continues for many years after an
eruption. A volcanic mud flow, whether or not it involves an eruption, is
called a lahar' it can move at speeds up to 90 miles per hour and may
attain depths of hundreds of feet. A large lahar can flow over or destroy a
dam. Further downstream lahars simply entomb everything in mud.
Lava: Lava flows from Cascade volcanoes tend to be small and slow
moving. The heat of the lava may start fires in its path. Flows may also
bury roads and other escape routes.
37
Volcanogenic earthquakes: Volcanic earthquakes are usually centered
within or beneath the volcano. Tremors may cause the avalanche of rock
and snow, landslides, and building collapse.
Vulnerability Analysis
The topographically low floor of the contiguous lower Green River and Duwamish
River valleys, from Auburn north to Elliott Bay, is considered to be at significantly
less (but not eliminated) risk of inundation by a Case I Iahar, relative to that risk
in the lower White River valley. This area will also be at significant risk from Case
II lahars or from subsequent redistribution of sediment from new Iahar deposits
under either of the two following conditions: (1) lahars or post -Iahar
sedimentation significantly reduces the available storage of Mud Mountain
Reservoir; (2) aggradation of the lower White River valley south of Auburn by
lahars or post -Iahar sedimentation from Puyallup valley causes the White and
Puyallup Rivers to drain northward into the Green and Duwamish River valley.
The largest Iahar originating at Mount Rainier in the last 10,000 years is known
as the Osceola Mudflow. This cohesive Iahar, which occurred about 5,600 years
ago, was at least 10 times larger than any other known Iahar from Mount
Rainier. It was the product of a large debris avalanche composed mostly of
hydrothermally- altered material, and may have been triggered as magma forced
its way into the volcano. Osceola deposits cover an area of about 550 square
kilometers (212 square miles) in the Puget Sound lowland, extending at least as
far as Tukwila, and to Commencement Bay, now the site of the Port of Tacoma.
Considering the active Cascade volcanoes, Tukwila could mostly likely receive
significant ash fall from Mt. St. Helens, Mt. Rainier, or Mt. Baker. Volcanic ash is
highly disruptive to economic activity because it covers just about everything,
infiltrates most openings, and is highly abrasive. Ash is slippery, especially when
wet; roads, highways, and airport runways may become impassable. Automobile
and jet engines may stall from ash clogged air filters and moving parts can be
damaged from abrasion, including bearings, brakes, and transmissions.
Large tephra fragments are capable of causing death or injury by impact, and
may be hot enough to start fires where they land. These hazards usually do not
extend beyond about 10 kilometers (6 miles) from the vent. Most tephra related
injuries, fatalities, and social disruptions occur at greater distances from the
vent, where tephra fragments are less than a few centimeters (1 inch) across.
Clouds of fine tephra can block sunlight, greatly restrict visibility, and thereby
slow or stop vehicle travel. Such clouds are commonly accompanied by frequent
lightning.
38
When inhaled, tephra can create or aggravate respiratory problems. Accumulation of
more than about 10 centimeters (4 inches) of tephra on the roof of a building may
cause it to collapse. Even thin tephra accumulations ruin crops. Wet tephra can
cause power lines to short out. Finally, tephra clouds are extremely hazardous to
aircraft, because engines may stop and pilots may not be able to see.
After the eruption of Mount St. Helens in 1980, much attention has been given to
the very real possibility of further volcanic activity in Washington State. Mount
Rainier, Tying to the south of Tukwila, has erupted three times in the past 150 years.
Though we could conceivably experience ash fall from any volcano, Mt. Rainier
poses the greatest variety of threats to our area. Other dangers to life and property
would depend on the degree of volcanic hazard, and the type and size of the
eruption.
Conclusion
A volcanic event in the Cascade Mountains may occur once or twice in a lifetime.
The Tukwila area is close enough to be directly affected by eruptions from any one
of five volcanoes. We are susceptible to a variety of hazardous situations during a
volcanic eruption; perhaps of greatest concern is the threat of large mudflows
causing damage to either the Mud Mountain or the Howard Hanson Dam. Seismic
intensities great enough to damage these dams would be of serious concern.
Geologic evidence shows major lahar and debris flows have filled the Green River
valley in the past. The overall effects of a major eruption could possibly produce an
incident of disaster that could be compared to the devastation of a major
earthquake.
Tephra and ash fall from a volcanic eruption could pose health concerns for
residents as well as damage property, disrupt communications, interrupt
transportation, and disrupt industry and the local commerce.
Experience at Mount St. Helens showed the need to identify specialized protective
equipment for both vehicles and people working in the shadow of a volcanic
eruption. Essential equipment for personnel would likely include breathing masks or
other respiratory protection. Similar air filtration would be required for vehicles
operating in heavy ash fall.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Volcanic Eruption Probability and Impact Analysis
39
WINDSTORM /TORNADO
Definition of Hazard
This type of hazard is an atmospheric disturbance characterized by a strong wind
and usually accompanied by rain, snow, sleet, hail and often thunder and
lightning. The National Weather Service classifies wind from 38 to 55 MPH as
gale force winds; 56 to 74 MPH as storm force winds and any winds over 75 MPH
as hurricane force winds. Destructive winds like those described normally occur
between October and March. The highest recorded wind speed recorded in the
greater Tukwila area was more than 81 miles per hour.
A tornado is violently rotating column of air, pendant from a cumuliform cloud or
underneath a cumuliform cloud, and often (but not always) visible as a funnel
cloud. Tornados are the most violent weather phenomena known. Their funnel
shaped clouds rotating at velocities of up to 300 miles per hour generally affect
areas of 1/4 to 3/4 of a mile wide and seldom more than 16 miles long.
Tornados are produced by strong thunderstorms. Such thunderstorms can also
produce large damaging hail, heavy amounts of rain, and strong damaging
winds.
History of Hazard
Winds of a destructive speed bringing varying degrees of damage, including
downed trees and utility lines, transportation interruptions and property damage
occur fairly regularly in this area. The most recent windstorms in our area of
disastrous proportion were the Inauguration Day Windstorm in January 1993 and
the storm in November 2006. Several hundred calls for assistance were received
by Tukwila Police /Fire /Public Works during the storm events. The City
experienced power outages and had to close several roads for hours. These
Presidential declared disasters had winds clocked at approximately 80 miles per
hour and caused hundreds of thousands of dollars in damage.
k r
I r 'r� A i v.
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al.r. i'�r yT' Y''9 `a"'_:`� a �r i rrM!rtz'c:g
2003 Windstorm damage
40
Other recent windstorms:
December 1995 California Express Windstorm
January March 1999 La Nina Winter Windstorm
December 2003 December Storm
Tornado sightings in Washington average 2 per year. During the past 30 years
there have been several tornados recorded in the area.
In 1972, a tornado struck the City of Vancouver, Washington 150 miles to our
south. During the course of this disaster, an elementary school full of children
was destroyed, as was a shopping center, a bowling alley and many homes. Six
people were killed and some three hundred were injured; damages were upward
of six million dollars. Most recently, the National Weather Service confirmed that
a F -1 tornado (100 -110) hit Enumclaw, during intense thunder and lightning
squalls that hovered over Western Washington on September 7, 2009. The
tornado caused property damage, destroyed several trees and caused power
outage.
Hazard Identification
A strong windstorm or tornado would likely affect power lines, transportation,
and lifeline routes. Structures are also vulnerable to the effects of wind from
falling trees and other debris.
If a tornado struck Tukwila, damage could be widespread. Businesses could be
forced to close for an extended period or permanently. Fatalities could be high
in densely populated areas. Many people could be homeless for an extended
period and routine services such as telephone or power could be disrupted.
Building codes continue to be strengthened to address potential impacts of
windstorms on structures.
Vulnerability Analysis
All areas of Tukwila are vulnerable to severe windstorms. Windstorms can
usually be predicted more accurately than other local storms. Tukwila can expect
at least one windstorm each year.
The problems arising from high winds, whether they come in the form of the
common windstorm or the destructive forces of a tornado, are many. Principal
damage occurs in the form of downed trees, utility lines, signs and traffic lights.
41
Damage to buildings potentially could occur. Secondary hazards associated with
high winds include power and other utility failures, as well as automobile,
railroad and air traffic accidents.
While it is possible to forecast the potential for a tornado formation, it is not
possible to forecast that one will in fact occur or where it will strike.
Conclusion
Windstorms are a common natural hazard that will affect not just Tukwila, but
will have widespread regional impacts. A windstorm of destructive velocity or a
deadly tornado could strike this area with little warning. Citizens should be
prepared and family plans and contingencies developed. Schools and businesses
should also support preparedness campaigns and programs to mitigate the
effects of a windstorm.
The most effective tool for alerting the public of severe storms is the National
Weather Service (NWS) weather warning network. Broadcasted over VHF radio,
NOAA weather radios with Emergency Alert System capabilities provide early
warning and notification needed to prepare for windstorms and tornado
watches /warnings.
The most common effects of these storms is the disruption of electrical and
transportation routes causing hardship and economical loss to citizens,
businesses and public assets.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Windstorm Probability and Impact Analysis
42
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43
TECHNOLOGICAL
MANMADE
HAZARDS
AIR TRANSPORTATION CRASHES
Definition of Hazard
This type of hazard is the failure of an aircraft to suspend itself in flight due to
mechanical or human error resulting in a collision with the ground.
A portion of Boeing Field (King County International) is located within Tukwila
and we are surrounded on all sides by local and international airport facilities.
Those in closest proximity are Sea -Tac International, Renton Municipal, Auburn
Municipal, Crest Air Park (south of Covington), and Cedar Grove Air Park
(southeast of Renton).
Most commercial air traffic is concentrated at Sea -Tac International and Boeing
Field. Renton Municipal and Auburn Municipal may be utilized as reliever airports
by charter and commuter aircraft; however, their primary function is use by
private and recreational aircraft. Crest and Cedar Grove Airparks are used
specifically for small private and recreational aircraft.
History of Hazard
Fortunately the Tukwila area has not experienced an incident with high Toss of
life or the devastation possible from the crash of a commercial airliner.
However, over the years small aircraft have come down in our area and serve as
a reminder of the possibility.
Hazard Identification
Due to the devastating effect on life and property when an air carrier accident
occurs, and the frequent news media accounts of what is termed the 'near miss',
we are aware that virtually every community is vulnerable to air traffic accidents.
The Tukwila area is no exception.
Small aircraft traffic is nearly impossible to control or predict, as current
regulations and safety equipment requirements are not as strict for small private
planes as they are for commercial carriers. Therefore one cannot logically
determine the probability or the possible location of a small aircraft accident. We
do know, however, that several accidents occur each year in the area. We must,
therefore, assume that the small aircraft disaster could conceivably happen
anytime or anyplace.
Statistics are more readily available on major aircraft accidents, giving a more
accurate picture of the potential for disaster and where it may strike. In recent
45
years airport congestion and air traffic noise have increased. Consequently,
commercial airline flight paths are alternated on a daily basis to decrease noise
exposure to specific neighborhoods. While the exposure to aircraft noise is
decreased by this method, the possible areas that could be affected by air
transportation crashes have increased.
It is known that 16% of all major airline crashes are low impact crashes on the
airport runway. 79% are high impact crashes with few or no survivors and are
within one and one half miles of the airport. The remaining 5% of crashes occur
enroute. In consideration of these facts and the proximity of Sea -Tac
International Airport and Boeing Field to Tukwila, we must consider the potential
of a major air transportation accident occurring in our area.
The area in which an aviation accident occurs will influence the effects of the
disaster on the community. If an aircraft goes down in an industrial or
residential area the number of fatalities may be much higher and the danger of
fire is enhanced. If the accident occurs during peak traffic periods the
responding forces may have problems reaching the area or transporting the
injured out of the area. An accident in a large open area could also present a
problem. With airplane wreckage scattered over a large area, crowd control
could be difficult, especially if there is easy access to the area. Such a
circumstance could easily overwhelm first response forces.
When a commercial airliner crashes the fire service will bear the burden of the
immediate effects; however, while the effects are often intense they are usually
of short duration. This type of disaster would place an unexpected burden on
Tukwila, mutual aid and Zone 3 agencies and the entire County. This would be
especially true if a large number of people on the ground were involved in the
accident.
There are other emergency elements impacted by an aircraft accident. Area
hospitals could be flooded with injured persons and blood banks could receive
large orders for blood. Law enforcement agencies would be hard pressed to
establish an effective crowd /traffic control; both Fire and Police would have to
establish effective, unified command operations; and a temporary morgue would
be required affecting the public health component.
Vulnerability Analysis
The potential for disaster exists for both the commercial air carriers and the
small private planes. Though we may think of an "air disaster" as being the
major commercial aircraft crashing and killing many passengers, we must also
consider the small private plane that could crash into a large business, apartment
46
building, shopping center or school housing several hundred people. Such an
occurrence would quickly exhaust emergency response capabilities and create
panic within the community.
The most obvious effect of this hazard is the potential loss of many lives, both on
board the plane and on the ground. Additionally, we must consider property
damage from ground impact and the potential fire and explosion hazard
associated with jet fuel. Aircraft impact with a fixed facility warehousing
hazardous substances should also be considered likely, given the prevalence of
those types of facilities in the valley area.
The major traffic patterns and the areas adjacent to airports present the greatest
potential locations an aircraft incident. Aircraft in a flight pattern merely passing
over Tukwila presents a small risk by itself. Weather related problems,
equipment malfunction and mid -air collision are the most likely scenarios for a
large disaster.
The largest number of aircraft accidents occurs within a five -mile radius of the
airport. Areas in the immediate vicinity and downwind of crash sites may also be
vulnerable to the effects of toxic air pollution.
While the airline industry has an excellent safety record, accidents continue to
happen and they will continue into the future. Even though the chance of a
major disaster resulting from an aircraft accident is relatively small, the potential
impact of an occurrence forces emergency planners to be aware of the
possibility.
Conclusion
Although a rare possibility, the catastrophic potential of a major aircraft crash in
Tukwila cannot be ignored. Tremendous damage to property, utilities and
transportation routes could result. Huge financial impact could occur, as well as
the inevitable heavy loss of life.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Air Transportation Crash Probability and Impact Analysis
47
COMMUNICATION FAILURE
Definition of Hazard
Communication failure is defined as the severe interruption or loss of private and
or public communications systems, including but not limited to transmission lines,
broadcast, relay, switching and repeater stations as well as communications
satellites, electrical generation capabilities, and associated hardware and
software applications necessary to operate communications equipment.
These disruptions may result from equipment failure, human acts, (deliberate or
accidental) or the results of natural or manmade disasters.
History of Hazard
Communication failures in our area have been limited to small -scale outages
associated with natural events such as severe weather storms and mainly
affecting landline and cellular telecommunication capabilities.
The Nisqually earthquake in 2001 caused a temporary disruption of the Regional
800MHz Radio system used primarily for public safety. Electronic mail failure has
occurred more frequently and is usually a short -term interruption causing assets
or data to be lost or unusable for a period of time.
Hazard Identification
All areas of Tukwila are susceptible to communications failures. A
communications failure would affect essential facilities and the day -to -day
operations of local government as well as the business community.
Sites of concern would range from dispatch agencies, Supervisory Control and
Data Acquisition (SCADA) systems, satellite uplink and downlink sites, internet
service provider sites, and the telecommunication industry switching sites.
Vulnerability Analysis
Communication systems, like other utilities may suffer disruption from natural or
manmade disasters. Seismic bracing should be reviewed on a regular basis to
ensure system stability. Transmission stations, land lines, satellites, cellular and
other facilities cannot be made completely secure and are therefore vulnerable to
disruption.
48
Satellites are vital in the respect that they provide communication capabilities
with the world outside of our local area. We depend on them daily for news,
weather forecasts and national defense. They are subject to the effects of
natural disasters such as cosmic debris and mass corona) ejections (MCE). They
are also subject to mechanical and electrical system failure like any other
communication device.
Emergency response capabilities are dependent upon communication systems
such as radio and telephone to direct and coordinate resources and to provide
vital public information and warning during emergencies.
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Communications Tower
Conclusion
Interruptions in day -to -day communications would create problems for
businesses, public agencies, citizens, and emergency services. The most common
problems would range from minor inconveniences of our citizens to loss of
49
production and revenues for businesses. Emergency services could face more
serious consequences, as poor or nonexistent communications could escalate
what would have been a minor emergency into a disaster situation.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Communications Failure Probability and Impact Analysis
50
ENERGY SHORTAGE
Definition of Hazard
An energy shortage could involve various types of energy resources. Those
shortages of primary concern would be petroleum, electricity, and natural gas.
Puget Sound Energy (PSE) and Seattle City Light (SCL) supply Tukwila
with electricity. PSE is a private company whose services are regulated by
the Washington Utilities and Transportation Commission. Six hydroelectric
plants, four coal -fired plants and six oil and natural gas fired plants fuel
PSE's electrical infrastructure. SCL is a publicly owned utility. Ninety
percent of its electricity is from hydroelectric plants on the Skagit and
Pend Oreille Rivers and the Bonneville Power Administration. Nationally,
99% of all power lines are above ground. These above ground lines are
susceptible to high winds and interference from trees and other
vegetation.
Most natural gas lines are owned by PSE and are located underground.
Underground lines vary in sizes and pressures and are susceptible to age,
ground movement, anomalies and flaws, and third party damage.
History of Hazard
The problems associated with petroleum shortages were vividly demonstrated in
1973 and 1974 during the Arab Oil Embargo, and again in 1979 when the United
States imposed an oil embargo on Iran. Minor petroleum shortages developed
during the 1989 Exxon Valdez incident and during the Persian Gulf War in 1990-
91. These events and others have caused the United States to utilize better
conservation measures and increase domestic petroleum production, thereby
reducing the need for imported petroleum products. Despite these efforts, the
United States still remains dependent upon imports for about 35% of its
petroleum needs.
Hydroelectric dams produce the majority of the electricity in Washington State.
Low precipitation years have produced low river flow conditions that have
resulted in insufficient amounts of water to operate hydroelectric plants.
The national energy system has three regions with each having a series of
interconnected grids. The Western region has recently been exposed to scant
sufficiency and power shortages, particularly in California. Some areas have
experienced rolling blackouts dating back from 1996 to as recently as 2001.
Rolling blackouts can occur due to line loading, when the transmission system is
stressed because it is operating at or near full capacity. Rolling blackouts are also
known as emergency load curtailments and involuntary conservation.
51
The Inaugural Day Storm of January 20, 1993, caused massive electrical power
outages throughout the Puget Sound area. A total of 880,000 customers were
without power from Olympia to Everett. During the December 1996, December
2003, and November 2006 wind and ice storms, hundreds of thousands of area
residents lost power and in some cases, lost the ability to heat their homes and
businesses for days.
Hazard Identification
All areas of Tukwila are susceptible to petroleum, electrical, and natural gas
shortages.
Vulnerability Analysis
Electricity:
An electrical shortage is not a major concern for Tukwila due to Washington's
proximity to substantial amounts of electricity transmitted from Canada to
California. Although load- resource balance and the likelihood of rolling blackouts
are minimal, regional supplies are tight.
The transmission system is more than 40 years old. It experiences high
utilization and requires more frequent maintenance. Interruptions in the
transmission system due to interference would be of concern. This could be the
result of a drought condition where increased loads cause electric lines to heat
up; when lines get too hot they sag. Lines can sag into trees and other
vegetation. Large wild land fires also cause carbon buildup on transmission lines
and may weaken tower structures, causing them to collapse.
A major failure of electrical supply systems (blackout) would have a large -scale
impact on everyone affected. Major electrical failure would have a domino effect
on nearly all supplies and services. Homes would have no electricity. Businesses
would be unable to operate and would close their doors. Other utility systems
would fail without power to run them. Disruption of emergency services would
occur. There are few things which we depend in our day -to -day lives which
would be unaffected by electrical failure.
Natural Gas:
The vulnerabilities of the natural gas system are Tess than those of the electricity
system mainly because the infrastructure is underground. The two most common
causes of gas system failures are:
Land movement mainly from earthquakes and landslides. This damage
52
could include a catastrophic systems failure in which ground movement
may sever pipe segments allowing gas to escape. Because gas is lighter
than air, gas leaks in open areas are not as major a concern as leaks in an
urban or confined setting.
Integrity Toss mechanical damage mainly through third party damage by
excavators or utility owners /operators. Although RCW 19.122 requires the
use of a "one call" system, this does not always occur. Third party
damage can introduce dents with gauging leading to pipe failure or an
outright rupture of the line. Internal anomalies can also lead to the loss of
pipe integrity. Internal corrosion, the age of the pipe and general thinning,
or other construction flaws can lead to pipe failure.
Conclusion
Major effects of energy shortages include inconvenience to consumers, reduced
heating and lighting capability, reduced production in all sectors, potential failure
of transportation, water and waste, communications, information and banking
systems. Efforts made to create makeshift heating and lighting often lead to
fires, explosions and asphyxiation. In addition, emergency response capabilities
may be severely hampered.
Homeowners and businesses need to educate themselves on all safety measures
associated with energy outages and shortages. The safe use of emergency
generators and how to shut off utilities are key first steps to safely mitigate an
event.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
LLowiP`roba ty1, Low Probability Low Probability
(LowfImpactPl..., (Moderate Impact) (High Impact)
Energy Shortage Probability and Impact Analysis
53
HAZARDOUS MATERIALS
Chemicals are found everywhere. They purify drinking water, increase crop
production, and simplify household chores. But chemicals also can be hazardous
to humans or the environment if used or released improperly. Hazards can occur
during production, storage, transportation, use, or disposal. Our citizens and
community in general are at risk if a chemical is used unsafely or released in
harmful amounts into the environment where citizens live, work, or play.
Hazardous materials in various forms can cause death, serious injury, long
lasting health effects, and damage to buildings, homes, businesses and other
property. Many products containing hazardous chemicals are used and stored in
homes and businesses routinely. These products are also shipped daily on the
nation's highways, railroads, waterways, and pipelines.
Chemical manufacturers are one source of hazardous materials, but there are
many others, including service stations, hospitals, and hazardous materials waste
sites.
Varying quantities of hazardous materials are manufactured, used, or stored at
an estimated 4.5 million facilities in the United States -from major industrial
plants to local dry cleaning establishments or gardening supply stores, of which
we have plenty in Tukwila.
Hazardous materials come in the form of explosives, flammable and combustible
substances, poisons, and radioactive materials. These substances are most often
released as a result of transportation accidents or because of chemical accidents
in plants.
Definitions
The following definitions include types of hazardous materials. Understand these
definitions include their production, use, storage, transportation and disposal. If
found uncontrolled, they place life, environment and property at significant risk.
Illegal drug /meth labs present yet another significant risk. Recent history and
current events show an increased threat from terrorists using hazardous
materials, including Weapons of Mass Destruction, (WMD). For the purpose of
this document, the terms hazardous materials and dangerous goods will be
used interchangeably.
Hazards are things that are potentially dangerous or harmful; often the root
cause of an unwanted outcome.
54
Hazardous substances are materials that pose a threat to human health
and /or the environment, and any substance designated by the Environmental
Protection Agency (EPA) to be reported if a designated quantity of the substance
is spilled into the waters of the United States or is otherwise released into the
environment.
Hazardous wastes are by- products of society that can pose a substantial or
potential hazard to human health or the environment when improperly managed,
that possess at least one of five characteristics (flammable, explosive, corrosive,
toxic, or radioactive), or that appear on the EPA lists.
Hazardous chemical is any hazardous material requiring an MSDS (Material
Safety Data Sheet) under OSHA's Hazard Communication Standard. Such
substances are capable of producing fires and explosions or adverse health
effects such as cancer, burns, or dermatitis'.
Hazardous materials are subject to regulation by a variety of local, state and
federal agencies through an assortment of labor, building, environmental, and
transportation laws, and their amount and location are also subject to City of
Tukwila Zoning Code and State of Washington regulations.
History of Hazard
On December 4, 1984, a cloud of methyl isocyanate gas, an extremely toxic
chemical, escaped from a Union Carbide chemical plant in Bhopal, India. More
than 2,500 people lost their lives. Tens of thousands more were injured, some
with permanent disabilities.
Over the years and throughout the United States, concerns over incidents of
hazardous material incidents has risen due to the frequency and potential
damage these events can cause. This concern has led to the development and
formation of specialty teams, trained and equipped with advanced technical tools
and proper personal protective equipment to handle these situations. Demand
for use of these teams with their advanced training and procedures have grown
significantly over the years.
As a retail and transportation hub in the state of Washington, Tukwila has over
2000 businesses in our city, several of which store, use, sell or manufacture
hazardous materials. Of those 2000 44 are classified as a type "H"
(hazardous) occupancy, per the International Fire Code. We have over 44 sites
that Fire Prevention Bureau has issued Hazardous Materials permits to. During
the period from 2000 to present, Tukwila has responded to over 1100 incidents
categorized as calls involving hazardous materials. That is an average of over
55
150 Hazardous Materials related calls per year. These calls range from flammable
liquid spills and leaks, to unknown chemicals, to a full specialized team response.
Tukwila has had two fuel tractor trailer tanker fires in recent history. Both
resulted in major disruption to regional transportation and environmental
problems. We have had multiple train derailments and recently added the Sound
Transit Light Rail that runs the full length of our city. There have been airplane
crashes that resulted in national and international news coverage. Finally, we
have had many river incidents involving cars in the river, and most recently a
boat that was leaking several gallons of fuel.
Hazard Identification
With our large retail and manufacturing districts, our city has an above average
exposure to the use, shipment and storage of host different types of hazardous
materials. Being the central point between Seattle, Tacoma and SeaTac
International Airport, having three major freeways /highways, a major
underground pipeline and two major rail lines, we have become a main traffic
pipeline for hazardous materials. If they are not stored in town, they are en-
route to other hazardous materials centers in the Puget Sound Region. Tukwila's
exposure /risk to hazardous materials throughout the City is critical.
Transportation of hazardous materials over the highways poses the greatest
potential threat to the community. It is dominated by flammable and
combustible liquids such as gasoline and fuel oil that represent about 30% of the
total. Other hazardous materials transported by truck include; nuclear materials,
sulfuric acid, anhydrous ammonia, caustic soda, liquefied petroleum gas (LPG),
hydrochloric acid, nitrogen, nitric acid and sodium chlorate. These materials are
heavily transported and move through Tukwila on a daily basis.
Interstate 5 carries the heaviest volume of hazardous materials in the state. The
intersection of Interstate 5 and Interstate 405, which is in Tukwila, is the busiest
intersection in the state! Very little hazardous materials transported across state
doesn't go through this intersection. State Routes 99, 518, 599, and I -405 also
run through our city, and are major hazardous materials routes. The shipments
of hazardous materials by truck are conservatively estimated in excess of 60,000
bulk shipments annually and do not include materials transported between
locations within the City.
Rail transportation of hazardous materials is also a factor to be considered. Rail
transportation of hazardous materials along the corridor between Tacoma and
Everett is the heaviest in the state. Two major rail lines run through the Green
River Valley and through our city from the north to the south. Regular
shipments of chlorine, LPG, caustic soda, anhydrous ammonia, methanol, vinyl
56
chloride, and motor fuel have origins or destinations along this corridor. Tukwila
also has the BNSF Burlington Northern Santa Fe intermodal rail yard.
Storage and use of hazardous materials within Tukwila is currently so widespread
that it is impossible to single out one particular area that has the greatest
potential for an incident. Tukwila has over 30 facilities with Class H occupancy
and close to 50 that have reportable quantities requiring a Hazardous Materials
permit.
There are multiple underground pipelines that run through the city. There are
two major fuel pipelines, one of which runs directly under our central business
district. The other runs along the railways. Both lines carry thousands of gallons
of fuels per minute and pose a huge risk to our community.
We also have a web of underground natural gas lines throughout the city. These
pose a risk in and of themselves due to the extreme flammability of the vapors.
Natural gas is used in the majority of our businesses and residence, including the
Westfield Mall.
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Tukwila Hazardous Material Team members
57
Vulnerability Analysis
The potential exposure to hazardous materials is very complex and probably the
most technological hazard in the City. Tukwila has a few chemical producers and
several storage and warehouse facilities. With all our industrial and
manufacturing plants, we are a major industrial consumer of hazardous
materials.
Since the adoption of SARA (Superfund Amendment and Reauthorization Act)
Title III/ EPCRA (Emergency Planning and Community Right to Know Act), there
have been facilities identified within Tukwila which use and store "Extremely
Hazardous Substances" in quantities large enough to require emergency planning
for those individual facilities and surrounding area. The chemicals included in
the EPA list of "Extremely Hazardous Substances" are primarily chemicals which
are extremely toxic, and when released are immediately dangerous to life and
health of humans and animals and can cause serious damage to the
environment.
An accident involving hazardous materials can happen anytime and anyplace.
The danger to life, environment and property is dependent on the product type
and amount of material involved. A small amount of an extremely hazardous
substance, (EHS), can be more dangerous than a large spill of a less hazardous
substance. The release of hazardous materials into the air has the highest
potential of being life threatening. This type of release can occur as the result of
a tank rupture due to an accident or over pressurizing, pressure release valve
operating for a variety of reasons, or simply a leaking valve from mechanical
failure, or lack of maintenance. Many life threatening gaseous chemicals
routinely found in the area are in abundance and include propane, acetylene,
nitrogen, chlorine, anhydrous ammonia, formaldehyde and cyanides. Many other
hazardous chemicals stored locally can become airborne as the result of fire or
reaction to other chemicals.
Flammable and combustible liquids such as gasoline and diesel represent the
largest class of hazardous materials in Tukwila. Because of their commonality,
they are probably the most likely substance to cause a chemical emergency in
Tukwila.
An often overlooked, but very common hazardous material is gasoline. The
average individual may not consider the fuel they put in their car extremely
dangerous. Considering the fact that the vapors from one gallon of gasoline
provide the same damage potential as fourteen sticks of dynamite! We have had
two gasoline tanker fires in Tukwila. Both resulted in huge environmental
problems and major disruption to the regional transportation routes. Another
potential scenario is the train tank car rupture and explosion of liquefied
58
petroleum gas (LPG). Many trains moving through Tukwila carry multiple tanks
of this substance. An accident involving this material could result in a Boiling
Liquid Expanding Vapor Explosion, known as a BLEVE. These incidents will
certainly destroy property and has a very real potential to cause casualties.
The cleanup and recovery from a hazardous materials incident is very time
consuming as well as costly. It is possible that a spill in Tukwila could enter
storm drains and waterways before it could be contained. Ecological damage to
the area aquifers and wildlife could be substantial. As happened with both our
tanker fires, an incident could send dangerous chemicals into the Green River,
downstream to the Duwamish River and into Puget Sound. Hazardous
substances entering sanitary drains could create serious problems at Metro
treatment facilities should they mix with incompatible material. Costs associated
with a hazardous material spill cleanup can run several thousand dollars for a
small spill, and into the hundreds of millions for an accident of disastrous
proportion.
Thousands of possibilities exist for hazardous material emergencies. Everything
from toxic gas releases which have the potential to kill thousands, to oil spills
which can ruin environmentally sensitive areas for generations, can and do
happen. Spills along roadways, parking lots and inside facilities occur almost
daily to some degree. We must remember that each of us is vulnerable to the
dangers of chemicals on the highway, in our work places, our schools, and our
homes.
Conclusions
Tukwila has an above average amount of hazardous materials, and an extremely
high risk and potential for several scenarios that could result in disaster! Between
our having underground pipelines, major freeways, an International Airport, two
major railways, a river and major industrial and manufacturing plants, we are at
high risk. Any incident in which hazardous materials are involved has the
potential for escalation from a minor incident into a full scale disaster. The
hazardous properties of chemicals, fuels, radioactive materials and other
potentially dangerous substances have the ability to contaminate the air, water
and other areas of the environment. We all know they are harmful to human,
animal and plant life as well. The potential for loss of life, environmental
contamination and extensive property damage is always high when hazardous
materials are involved in an accident or are improperly handled. We have
59
identified and recognize the risks we have. We are confident that our training,
equipment and dedication to protecting our citizens and community will enable
us to respond quickly, professionally and efficiently.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact)
(Hi op Impact)
Moderate Probability Moderate Probability 1;3U," f Q
(Low Impact) (Moderate Impact) _7 ire h r :x1
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Hazardous Materials Incident Probability and Impact Analysis
60
HAZARDOUS LIQUID PIPELINE
Definition of Hazard
The Olympic Pipe Line Company pipeline system consists of over 400 miles of
pipelines extending from refineries in northwest Washington to Portland Oregon.
These pipelines carry refined liquid petroleum products including diesel, aviation
fuel and gasoline. Underground high pressure pipelines carry 441,000 barrels or
18,700,000 gallons of fuel daily.
The pipeline system in Tukwila was constructed in 1965. One segment of the
pipeline system enters Tukwila from the Renton Pump Station to a location in the
vicinity of Strander and Interurban Trail. This pipeline system exits the City limits
at S -180 Street and continues south into the City of Kent. The second segment
also enters the City from the Renton Pump Station and travels into the City of
SeaTac.
History of Hazard
43 spills have been reported since 1965 totaling almost 821,000 gallons. Olympic
Pipeline accounts for 65% of liquid fuel spills in Washington since 1985. In 1986,
31,000 gallons of jet fuel leaked into the Des Moines Creek. In 1999, a rupture in
the pipeline located in Bellingham resulted in three fatalities, and the release of
approximately 236,000 gallons of gasoline into the Whatcom and Hannah
Creeks. The explosion caused extensive damage to the creeks, shorelines and
other natural resources.
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Pipeline Explosion June 1999
61
The estimated property damage in Washington State is $10,759,357 from
pipeline accidents. Tukwila has been fortunate not to have a significant pipeline
incident.
Hazard Identification
General Physical and chemical properties of petroleum products. Gasoline is
highly flammable and is easily ignited when released into air. Diesel and jet fuel
are combustible liquids and produce fewer vapors than gasoline.
Petroleum product vapors are heavier than air. Vapors can spread along the
ground and collect in low or confined areas, creating a vapor explosion hazard
indoors, outdoors, or in sewers. All products have increased volatility and may
form explosive mixtures with air when released under pressure from the pipeline
as an aerosol. Vapors may travel to source of ignition and flash back.
Petroleum products are Tighter than water, (Thus will travel on the surface).
Runoff to sewer or storm drain may create fire or explosive hazard.
Health hazards via inhalation or contact with material may irritate or burn skin
and eyes. Fire may produce irritation and /or toxic gases. Vapors may cause
dizziness or suffocation, Runoff may cause pollution.
The pipe is made by U.S. Steel via a High Frequency electric resistance welded
(ERW) process. The four cause categories of incidents in liquid pipelines are:
Anomalies, such as damage from construction equipment and corrosion,
cause 62% of the incident on liquid pipelines. An anomaly is an
imperfection in the pipe that if large enough could cause it to become a
defect which is generally considered to reduce the failure pressure of the
pipe to below the yield pressure of the pipe. The yield pressure is the
design strength of the pipe which if exceeded will be on the verge of
causing the pipe to permanently enlarge in diameter.
Incorrect operation causes 7% of the incidents on liquid pipelines.
Malfunction of pressure control equipment causes 5% of the
incidents on Liquid pipelines.
"Other" Causes such as gaskets, flanges, fittings, etc cause 27% of
the incidents on liquid pipelines.
62
FACTORS CONTIBUTING TO PIPELINE FAILURE
Movement. The Puget Sound region is seismically active, with hundreds of
earthquakes occurring each year. The pipeline is located in the Duwamish valley
which is made of soft soil or a sandy loam and is susceptible to soil liquefaction
during an earthquake. This force is analogous to those that move an unsecured
garden house causing lateral forces that strain the pipe. Some communities
have reported that the actual pipeline location, when checked by probing, is well
outside the supposed location or right -of -way (5 -10 feet wide). This outside force
can fatigue the pipe producing a partial collapse or buckling of the pipe.
Mechanical Damage. Most commonly caused through third party damage by
excavators or utility owners /operators. Although 19.122 RCW, Underground
Utilities provides legislation requiring the use of "one call" system, this does not
always occur. Third party damage can introduce dents with gauging leading to
pipe failure. The pipeline runs parallel to the Union Pacific tracks also exposing it
to mechanical damage should a derailment occur.
Internal corrosion. Corrosion leading to metal loss may cause general thinning
of the pipe, pitting of the pipe, crevice corrosion in electric resistance and flash
weld seams or stress corrosion cracking (SCC).
Cracks in the Seam weld that may be increasing in length and depth from the
operational pressure cycles that were created from inclusion on the weld line,
inadequate pressure during welding, and excessive trim of the excess metal
extruded during electric resistance welding.
Gouges without a dent in the body of the pipe that may be due to construction
damage. Also, cracks due to fatigue during shipment, stress corrosion cracks, or
hydrogen cracks due to the environment that forms at the pipe surface.
(Generally, these cracks are oriented along the length of the pipe or axially as
this is the direction that is perpendicular to the maximum stress in a pipe or
axially as this is the direction that is perpendicular to the maximum stress in a
pipe which is due to pressure.)
System failure such as:
Safety critical devices such as shutdown switches, control valve
interlocks and pressure relief valves.
Management of change to pipeline modifications that can impact
pipeline flow, surge pressures as well as the effectiveness of
existing safety equipment.
Improper tool selection or inadequate data review of inline
inspections devices. The type of defect expected must be known or
63
suspected so that the proper ILI tools can be selected for the
inspection. Several types of tools generally have to be run in order
to inspect the pipe for all of the potential types of defects. Flaws
may be missed due to the complex nature of the log interpretation.
Supervisory Control and Data Acquisition (SCADA) breakdown,
programming errors entered into the main computer can transfer to
the backup system if they are not independent of each other. For
safety critical equipment, redundancy does not truly provide
increased reliability if such systems can be easily linked to the same
failure (mirroring).
Vulnerability Analysis
The potential for damage to the liquid petroleum pipeline by a large earthquake,
third party damage, internal failure, terrorist act, or other initiating event
presents a risk of release incident. Only through continued training and
preparation by response personnel, maintenance on and the practice with
equipment, and safety- oriented integrity management principles can this risk be
reduced. British Petroleum and their subsidiary, Olympic Pipeline, have
responded with a significant improvement to the safety of their system.
A leak or rupture of the pipeline would expose vulnerabilities from:
Fire or explosion: Fire could cause a conflagration to surrounding
occupancies and put a tremendous strain on City resources. The Fire
department would need all available firefighters to control the blaze; law
enforcement to provide traffic and crowd control and possibly
evacuations; Public Works in supplying infrastructure expertise,
barricading and utility support. Other departments may receive emergency
tasking as well to assist with longer term issues of support and recovery.
Medical services, both public and private, may be overwhelmed if
casualties are high. Movement of product through creeks, rivers and storm
drains could cause downstream impacts and widespread fires.
Ground Contamination: This is a long -term problem as contamination
spreads over the permeable ground surfaces. While a concern, there is
little that can be done to stop or limit it unless there is a feature of the
topography that lends itself to natural containment. This includes paved
parking lots with curbs, streets, and natural depressions in the earth.
Ground contamination could require a massive clean -up operation lasting
several months.
Waterway Contamination; a rupture of the pipeline near the Green
64
River that allows product to flow down the banks into the waterway is
more likely than a rupture of the pipe under the river. Once in the river
the steep banks should help contain the vapors that are carried along with
the current and winds not allowing them to spread into adjacent
businesses and residences. The City has extensive storm drain systems.
Many of the storm drains are interconnected and create an ideal path for
flammable or combustible liquids as well as the resulting vapors. The
spread of product can be undetectable from surface streets until there is
either an explosion or a monitoring device is lowered into the storm
system.
Transportation; the proximity of the pipeline to major rail, highway, and
population centers would impact movement and commerce in the Green
River Valley and the region. Effects would be dependent on the type and
amount of product (leak or rupture), vapor, fire or both, time of day,
weather conditions, and delay in detection or reporting.
Conclusion
Since the June 1999 pipeline explosion in Bellingham some noted improvements
have been made in pipeline safety. The issue of Federal Pre emption over
interstate pipelines prevents local communities from having stronger safety
requirement of their own which could be tailored to the area's unique
environment. Issues of testing type and frequency, valve type placement, and
improved leak detection remain vague or non existent within Federal
Regulations.
Since the placement of the pipeline, the Tukwila population has grown.
Education of the risks, review of local ordinances, and the adoption of local land
use measures should be considered.
Economic losses resulting from a pipeline accident would be significant. Clean-
up costs and environmental remediation coupled with the possible loss of critical
utilities /infrastructure and transportation corridors would likely occur.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (Hi•h Im•act
Low Probability Low Probability
(Low Impact) (Moderate Impact)
Hazardous Liquid Pipeline Accident Probability and Impact Analysis
65
TRANSPORTATION
Definition of Hazard
Transportation, for the purpose of this analysis, will be defined as all forms of
ground transportation which move people and materials through Tukwila.
History of Hazard
While no major transportation disasters have occurred in Tukwila, traffic
accidents are a common occurrence. Development of the area has generally
decreased the speed of impact of our accidents, but unfortunately has increased
the frequency.
Hazard Identification
Increasing traffic congestion within the Tukwila area has given way to more and
more transportation hazards over a wider area. Freeways filled to capacity have
caused overflow on to alternative north south routes such as Pacific Highway,
Military Road, and the East and West Valley Highways. The Sound Transit Light
Rail station at the intersection of Southcenter Blvd and International Highway will
create a significant impact on local traffic.
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66
Vulnerability Analysis
The highway system which runs through Tukwila is the most commonly used
ground transportation system within the area. Though there is no accurate
figure for the number of vehicles traveling through the area daily, it does not
take an expert to recognize the traffic problems that currently exist.
Two state highways and two interstate highways run through Tukwila. Due to
the limitation of access points to these highways, many feeder roadways are
subject to interruption or gridlock during peak commuting hours. The vast
amount of construction in the area has also led to frequent traffic disruptions as
a result of detours and slow downs. An item of major concern is the potential
for complete gridlock in an emergency situation such as flood, earthquake,
hazardous material or other emergency, requiring an evacuation of homes and
businesses in a given area.
Bus traffic is steadily increasing bringing with it greater possibilities of multiple
casualty incidents due to traffic accidents.
While intersections and major highways are particularly susceptible, major
accidents can occur at any point along the roadway network. In addition to the
obvious injuries and property damage incurred at a major traffic accident, there
is great potential for hazardous materials to be involved in such an accident.
Emergency vehicles and crews are sometimes badly hampered by traffic
congestion. These delays may add to the seriousness of injury and increase the
potential for Toss of life at accident scenes and other emergency responses. A
slowdown in response to any type of an emergency due to traffic congestion is
detrimental to life and property within the community.
Railroad transportation routes run parallel to industrial development. There are
two rail systems within Tukwila, both running through the valley floor.
The addition of Sounder commuter trains running several scheduled trains
through the Tukwila area on a daily basis has created further congestion issues
during the heavy commute times. The hazard potential of railroad systems is
much like that of highway transportation. Trains, like any other form of
transportation, are vulnerable to accidents with other vehicles, derailments,
terrorist activity, and potential complication involving rail accidents with the
extremely large quantities of hazardous materials transported through Tukwila
on a daily basis.
67
Conclusion
The transportation system running throughout greater Tukwila is heavily
impacted and greatly increases our risk of major transportation emergencies.
High Probability High Probability sF High Probability
(Low Impact) (+Moderate Impact. (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Transportation Accident and Impact Analysis
68
WATER SHORTAGE /SYSTEM FAILURE
Definition of Hazard
This type of hazard includes the reduction in performance or complete failure of
part or all of the water supply system due to equipment failure, and natural or
manmade disasters.
History of Hazard
No catastrophic system failures have been experienced however shortages have
been and will continue to be of concern as a result of rapid growth in the area
and drought.
Hazard Identification
Tukwila and surrounding jurisdictions are susceptible to water shortages or
system failures regardless whether they are served by private or public systems.
Vulnerability Analysis
The City of Tukwila operates its own water supply system and provides water
service for most of the Greater Tukwila Area. Any interruption or failure of this
system would leave most of Tukwila's water needs unfilled.
Any utility system is subject to interruption or failure. The Tukwila water supply
is no exception. The City has taken precautions to safeguard the system such as
installing tie lines to other water districts. Water system failure may still occur
for a number of reasons including the lack of on -site generators for emergency
power. Anticipated water system hazards are earthquake, severe weather,
power failure, or system failure. The system is also subject to shutdown due to
environmental contamination from accidental or intentional causes.
Numerous problems may occur as the result of water shortages or system
failures. In addition to the obvious inconvenience of being without water for
daily needs, firefighting operations would be impacted. Sewer systems would
fail. The lack of necessary water supplies would create a serious public health
concern, and unemployment would occur at those businesses requiring water to
run day -to -day operations. Agricultural businesses would fail without water,
causing an interruption in the local food chain.
69
Conclusion
Water shortages, system failures and the chain of associated events would
interrupt businesses and day -to -day activities.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low. Probability Low Probability Low Probability
(Low Impact) (Moderate Impact) (High Impact)
Water Shortage Probability and Impact Analysis
70
CIVIL DISTURBANCE
Definition of Hazard
This type of hazard is a planned or random public uproar or disturbance of daily
community life. This hazard occurs most often when participants in mass acts of
civil disobedience become antagonistic toward authority, and authorities must
struggle to wrest the initiative from an unruly crowd. In the extreme, civil
disturbances include criminal acts of terrorism. Civil disturbances, in any form,
are prejudicial to public law and order.
History of Hazard
Turbulent eras of our areas history, notably the civil rights campaigns of the
1960's and the Boeing layoffs of the 1970's have produced civil disturbances that
have affected the Tukwila area.
More recently in 1999, the Seattle Police Department experienced the WTO
demonstrations that resulted in major
rioting in downtown Seattle.
1___---,Q The Tukwila Police Department was one
1 of several agencies called to assist.
di, ,a c r i G Pr from the riots were
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ii =b�ll,l. T um t H r r• Ti v.� transported to the King County Regional
i I '41i .ii, 1aa.�':,1. (t c�. ill,' Justice Center in downtown Kent.
Intelligence revealed that demonstrators
were threatening to riot and demand
the release of prisoners. Fortunately, it
did not happen.
King County Regional Justice Center
Other times, high profile trials have been conducted at the Regional Justice
Center and resulted in a much higher concern for security.
Large crowds at clubs and other public places have caused problems. Fights have
broken out in the parking lots. Some of these events have been controlled by
calling more police officers from surrounding jurisdictions to help (mutual aid).
Demonstrations have the potential to develop into a large scale disturbance.
Since the war in Iraq, anti -war demonstrations have become more prevalent.
71
Hazard Identification
Those areas normally vulnerable to civil disturbances are often thought to be
larger cities. However, the City of Tukwila is just as vulnerable. We are not
immune from activities and issues that lead to civil disturbances.
Vulnerability Analysis
The likelihood of civil disturbances increases daily given the fact that gang
members formerly staking their territory in large cities in California have
migrated north. Gang members do live in Tukwila. Others travel through or
socialize in Tukwila. Other groups with extremist viewpoints are also of concern.
Many of these groups have chosen to locate in our area.
Civil disturbance as a hazard could involve any large group of people assembled
for any reason. Included are large assemblies of people such as at Tukwila
Days, All Nations Cup, Rock and Roll Marathon, or other local /regional events.
Conclusion
In the event that a civil disturbance should occur, it would likely require crowd
control measures by law enforcement agencies and the need for rescue and
medical aid. Complications of this type of occurrence are: injuries, property
damage, traffic congestion, inaccessibility to the area involved and the possible
need to impose a curfew or even evacuate area residents.
High Probability High Probability High Probability
(Low Impact) (Moderate Impact) (High Impact)
Moderate Probability Moderate Probability Moderate Probability
(Low Impact) (Moderate Impact) (High Impact)
Low�'Proba`bilit�i
444 Low Probability Low Probability
(Li mpact) .1,, (Moderate Impact) (High Impact)
Civil Disturbance Probability and Impact Analysis
72
VI. Summary of Hazard Risk in Tukwila
The conclusion drawn from the Hazard Vulnerability Analysis and Risk
assessment is that Tukwila's highest risk is Flooding. Despite USACE's efforts to
construct an interim seepage barrier wall, and improve the right abutment
drainage system at the Howard Hanson Dam, and efforts to construct /install
flood protection equipment along the entire levee system, there is still a
significant risk of flooding to the Green River Valley communities for the next few
flood seasons.
Risk
Hazard Frequency /Probability Impact (Probability ±Impact)
Flooding High High High
Windstorm/Tornado High Moderate High
Earthquake Moderate High High
Snow /Ice Storm Moderate Moderate Moderate
Landslide Moderate Moderate Moderate
Hazardous Materials Moderate High Moderate
Transportation Moderate Moderate Moderate
Hazardous Liquid
Pipeline Low High Moderate
Air Transportation Low High Moderate
Communications Moderate Low Moderate
Volcanic Eruption Low Moderate Moderate
Urban Fire Low Moderate Moderate
Civil Disturbance Low Low Low
Energy Shortage Low Low Low
Drought Low Low Low
Water Low Low Low
Shortage /System
Failure
Summary of Hazard Risks
73
Flooding is followed by other natural hazards including Severe
Windstorm/Tornado, Earthquake, Snow /Ice Storm, and Landslide. This analysis
is consistent with the disasters that have struck the City.
Based on the hazard risk assessments and conclusion drawn above, the focus of
Tukwila's Hazard Mitigation Plan will be on those hazards determined to be
"high" or "moderate" risk. Other hazards that pose a "low" risk will continue to
be evaluated during future updates to the Plan, but they may not be fully
addressed until they are determined to be of high or moderate risk. This enables
the City to prioritize mitigation actions based on those hazards present the
greatest risk to lives and properties.
VI1. Critical Facilities Infrastructure
Critical facilities are those that support government and first responders' ability
to take action in an emergency. They are a top priority in any comprehensive
hazard mitigation plan. The matrix below includes a list of facilities and /or
structures that have been determined to be critical in nature, structures or
facilities that would seriously impact not only the quality of life in Tukwila, but
also the sustainability and survivability of the City residents. Critical Facilities
include:
Essential facilities which are necessary for the health and welfare of an
area and are essential during the response and recovery phase of a
disaster. These include: governmental facilities, public safety facilities,
schools;
Transportation systems such as arterial roads;
Lifeline utility systems such as: potable water, waste water facilities,
power grid and communications systems.
The City's critical facilities are all vulnerable to most natural and
technological /manmade hazards identified in Section V of this Plan. Tukwila's
critical facilities are provided at Attachment 8.
VIII. Capability Assessment
A matrix is provided below to portray Tukwila's legal, regulatory, administrative
and technical capabilities. These capabilities play a significant role in the City's
effort to mitigate potential hazards that adversely affect residents, businesses,
and infrastructure.
74
CITY OF TUKWILA CAPABILITIES
Regulatory, Tools Windstorm,
(Codes, -Ordinances, Plans) Flooding Snow, Ice Landslides
T.... hquak
Earl kes
Building Code X X X X
Zoning Ordinance X X
Special Purpose Ordinance
(Critical or Sensitive areas
Ordinance) X X X
Growth Management X X
Stormwater Management
Plan /Ordinance X X X
FEMA National Flood Insurance
Program X
Capital Improvements Program X X X X
Site Plan Review Requirement X X
Comprehensive Plan X X X
Comprehensive Emergency
Management Plan X X X X
Shoreline Master Plan X X X
1Nindstorm,.
StaffjPer nel Resources: z s Flooding `,Snow,. Ice, Earthquake. Landslide
Planners Engineers with
knowledge of land development
and land management practices X X X X
Engineers /professionals trained in
construction practices related to
buildings and /or infrastructure. X X X X
Planners or engineers with an
understanding of natural hazards. X X X X
Floodplain Manager X X X
75
Personnel skilled /trained in GIS
applications X X X X
Emergency Manager X X X X
Grant Writer X X X X
Windstorm
IFiscal. Caoabilitt,. Sno ice Ea�tl�ci a& L n lslit�e,
Community Development Block
Grants (CDBG) X X X X
Capital Improvements Project
Funding X X X X
Authority to Levy Taxes for
specific purposes X X X X
User fees for water, sewer, gas or
electric service X X X X
Incur debt through special tax and
general obligation bonds X X X X
IX. Mitigation Strategy
The City's mitigation strategy is derived from an in -depth review of the existing
vulnerabilities and capabilities outlined in previous sections of this Plan combined
with the underlying purpose of strengthening Tukwila's resilience to natural and
manmade hazards summarized in Section V of this Plan. The strategies are all
tied directly to the six goals (Protect Life and Property, Support Emergency
Services, Increase Public Awareness, Preserve Natural Systems and
Resources, Encourage Partnerships, and Enhance Planning Activities)
and the supporting objectives summarized in Section II of this Plan.
Vital to the City's mitigation strategy are three major components:
0 Continuation and enforcement of City codes, policies, plans, and
programs. The City's land use, and zoning regulations and building
codes that mandate requirements for new construction and upgrades all
play a vital role in keeping the community and the environment safe.
Adopting certain land use restrictions that limit private rights to use of
76
property must be accomplished through a strong public education and
input process.
The National Flood Insurance Program (NFIP) is one of the most
important components to the City's mitigation strategy. Together with
thousands of communities across the United States and its territories,
Tukwila participates in the National Flood Insurance Program (NFIP), CID
Number 53091.
Records indicate that Tukwila entered the NFIP on August 3, 1981.
Participation in the NFIP allows Tukwila homeowners, renters, and
businesses to purchase federally backed flood insurance. Currently,
there are 1,068 flood insurance policies in force in Tukwila. This
represents $362 million total insurance in force. Fortunately, as of April
2010, there are no repetitive loss properties in the City. To date, there is
one paid Toss totaling $1,300.
The City will continue its efforts to communicate the importance of the
NFIP through public outreach and education programs. A wide array of
audience will be targeted in future outreach and education forums
including elected officials, residents, businesses, developers, and special
interest groups. A concerted effort will be made to encourage
particularly those businesses, renters, and homeowners that are adjacent
to Flood Zone X areas (Tukwila's current Map date is April 19, 2005) to
obtain flood insurance.
The City's Flood Plain Manager plays an integral role in implementing the
mitigation strategy. The City is very fortunate to have a technically adept
senior engineer who oversees and manages the City's flood plain
management program. He aggressively enforces the local floodplain
management ordinance by reviewing, approving /disapproving, and
managing all flood zone control permit requests and activities that may
impact special flood hazard areas within the City.
In 2011, the Flood Plain Manager will work closely with the Department
of Community Development Building Official in the adoption of the new
Flood Plain Management Ordinance. In the short term, they will work
together to identify short term training requirements that may be
required to implement the new flood plain regulation.
In 2013, the City expects a Community Assistance Visit (CAV) from
Washington State of Ecology. The CAV is usually every five years with
the last visit conducted on May 21, 2008. The visit will assist the Flood
77
Plain Manager in identifying any shortfalls, strengthening the City's Flood
Plain Management Program and meeting regulatory requirements.
For the first time in its history, the City has all its critical facilities that are
located in the potential flood affected areas covered under the NFIP.
The City will continue maintaining compliance and good standing in the
NFIP and will consider participating in the NFIP Community Rating
System.
Investment of resources. It must be recognized that enhancing the
resiliency and sustainability of the City will require substantial investment
of resources. The City will continue to make improvements within its
current resource capacity and funding authorization; however many of
the mitigation goals, and objectives included in this Plan cannot be
implemented without external funding sources. The City must
aggressively pursue State and Federal grants to accomplish vital
mitigation initiatives.
Implementation of Mitigation Initiatives. This component of the
City's mitigation strategy poses some challenge because in many cases,
significant capital investments are required. Each of the mitigation
initiatives in this Plan was identified by City first responders and subject
matter experts within City departments as they relate to protecting lives
and property, supporting emergency services, and accomplishing other
goals and objectives.
For this 5 -year Hazard Mitigation Plan, mitigation initiatives are focused
on the natural hazards that pose the highest risk to the City. Based on
the conclusions drawn from the Hazard Vulnerability Analysis and risk
assessment (Section V), Tukwila's highest risk is flooding followed by
severe windstorm, earthquake, snow /ice storm and landslide.
Due to the issues at the Howard Hansen Dam, the Tukwila Team which
includes representatives from all departments has been engaged in one
of the most comprehensive flood planning effort in years. This planning
effort includes meetings, and partnerships with Auburn, Kent, Renton,
Seattle, King County, and the U.S. Army Corps of Engineers (USACE).
The City has conducted over twenty (20) flood preparedness meetings
with residents, property owners and businesses. During the past few
months, the City spent approximately $2.2M in emergency flood
mitigation initiatives. These activities include:
Gilliam Creek Basin Storm water Overflow Project. This
Project involved the construction of a 24" overflow pipe that
78
would allow the Gilliam Creek Basin to drain to a City pump
station reducing the potential of flooding in the City's commercial
business district.
Storm Lift Station #18 Improvements. This Project
provides a secondary backup pump and increasing capacity by
replacing the existing 8" pump with two 10" pumps.
Levee Reinforcement Project. Partnering with the USACE,
and King County, the City embarked on an emergency levee
reinforcement project that is now substantially complete. The
installation of approximately 25,000 lineal feet of supersacks
(giant 4,000 pound heavy duty sandbags) and 10,000 lineal feet
of HESCO sand containers on top of Tukwila's levee system has
raised the levee's capacity to handle an estimated 16,900 cfs flow
at the Auburn Gauge.
Flood Protection Demonstration Project: This project
included the demolition of an old cabin, land clearing and the
installation of 225' of HESCO sand barriers along a segment of
the Duwamish River.
Installation of an All Hazards Alert Broadcasting (AHAB)
System. In 2010, the City installed and tested an AHAB system
at the City of Tukwila Fire Station 51 to provide all- hazards
warning to the surrounding areas.
While the primary focus during the past few months was on flooding, the
City's first responders consisting of police, fire and public works personnel
identified other mitigation initiatives that became part of the preparedness
strategy to deal with other hazards. These mitigation actions /initiatives
include:
Standby Power Upgrades: Installation of standby generators to
City Hall, and Fire Stations 52, 53, and 54 to facilitate continuity of
operations during power outages due to windstorms, earthquakes,
and other natural disasters. This initiative was completed in
September 2009. Total cost was $595,279. Responsible
Department: Public Works.
Seismic Study: The City invested $232,746 to conduct a seismic
evaluation of some of its City facilities to determine the buildings
expected performance during an earthquake and to identify potential
structural deficiencies. In general, all the City facilities evaluated
79
were determined seismically insufficient and would require either
seismic upgrades or replacement. The results of the study will be
incorporated into Tukwila's Facilities Plan and will be considered in
this Plan and subsequent Plan update. Responsible Department:
Public Works.
Permanent City Emergency Operations Center: The City's EOC
is located in the Police Department Training Conference Room. The
facility is small and cannot accommodate all the anticipated EOC
functions and personnel needed to manage a protracted emergency
event and support the City's Continuity of Operations Plan (COOP).
Construction cost for an EOC is approximately $1.2M. Responsible
department: Emergency Management /Public Works.
City Maintenance Facility Replacement Project: The City's
current facilities, fleet and maintenance shops are inadequate to
support and restore essential services following a significant
emergency event. The shops currently don't have back -up
emergency power and have failed seismic evaluations performed by a
certified structural engineering firm. A new City Maintenance and
Operations facility would allow continuity of operations under
emergency conditions for an extended period of time. Cost of the
Project is approximately $10M. Responsible department: Public
Works.
Boeing Access Road Bridge Replacement Project: This bridge
is structurally and seismically deficient. The Boeing Access Road
Bridge is a major east west arterial that provides access between
East marginal Way and the I -5 corridor. Bridge failure will severely
impact freight mobility, and threaten public safety. The replacement
cost is estimated at approximately $30M. Responsible department:
Public Works.
Interurban Ave South Project Wall Containment: During
severe winter storms, landslides have occurred on the steep hillside
along the west side of Interurban Avenue. Construction of the
containment wall will prevent landslide debris from blocking the
traffic lanes of Interurban Avenue which serve as a principal arterial
for over 20,000 motorists. Containment wall will also enhance the
safety of motorists and pedestrians. Project cost is estimated to be
approximately $.5M. Responsible department: Public Works.
Community Outreach and Education: Public outreach and
education efforts are critical to the City's overall preparedness
80
strategy. The recent meetings and outreach efforts that the City
conducted have raised the public's awareness regarding hazards that
could occur in Tukwila, and how those hazards could impact the
community. The City will continue to conduct meetings and outreach
activities that will cover more than just high risk natural and man -made
hazards. Low risk hazards such as drought, water shortage, and civil
disturbance will be included in future agendas. Responsible department:
Emergency Management.
X. Mitigation Priorities. As emphasized earlier, for this first 5 -year Hazard
Mitigation Plan, Tukwila will concentrate on the highest priority mitigation
initiatives. The following criteria were considered in establishing the priorities for
the mitigation initiatives that are planned for implementation:
Life /Safety Consideration. Does the initiative address a life /safety issue?
An evaluation of the urgency of the initiative. How urgent is the initiative?
Cost Benefit Analysis. In determining the feasibility of the mitigation
initiative, a cost benefit analysis was performed by dividing the estimated
cost into the estimated saving or benefit. Where life- saving initiatives will
be involved, the cost benefit analysis will reflect a base figure of $2.3
million is determined to be the "benefit" or "savings This figure was
suggested by King County.
An evaluation of funding availability and how the initiative fits into the
City's operations and budget policies. While life /safety and other criteria
are important guiding principles, the availability of funding plays a
significant role in setting priorities.
Given the criteria summarized above, the mitigation initiatives for the next few
years are provided in greater detail at Attachments 9 -12 and are prioritized as
follows:
Priority 1: Construction of a permanent City EOC
Priority 2: Retrofit /Replacement of City Facilities
Priority 3: Boeing Access Road Bridge Replacement
Priority 4 Interurban Avenue S Project Concrete Containment Wall
81
XI. Relationship with City Plans and Policies
The City of Tukwila will integrate the proposed mitigation initiatives, projects,
and strategies into all current and future City plans and policies. Hazard
mitigation projects will be included in the Capital Improvement Program (CIP),
operating budget, and grant proposals to State and Federal agencies. The City
will consider hazard risks and vulnerabilities data when amending the City's
Comprehensive Plan, Zoning Ordinance, Building Codes, Sensitive Area
Ordinance, Flood Plain Management regulations, Comprehensive Water System
Plan (to mitigate Drought Hazard), and other planning and policy documents as
appropriate.
XII. Plan Maintenance and Update
This Hazard Mitigation Plan will continue to be updated and refined to mitigate
potential human and property losses in Tukwila and ensure that it is in line with
the goals and objectives, and compliance with State and Federal regulations.
Once adopted, the City's Emergency Management Director will be responsible for
the maintenance and update of the Plan.
Tukwila's Plan will be reviewed on an annual basis by the Emergency
Management Director or his /her designee. At a minimum, the following actions
will be taken during the review process:
Re- evaluate Tukwila's hazard reduction goals and objectives to ensure
that they are current and still valid.
Determine whether there are components of the Plan's risk assessment
that need update /refinement.
Review and update the Plan to reflect progress in mitigation
efforts /activities and changes in priorities, funding availability or
strategies.
Reassess and re- evaluate recent and future and changes in land
development and annexations including Tukwila South.
Discuss /determine potential community outreach activities.
Additional reviews may be conducted periodically following drills, exercises or an
actual disaster or significant event.
As part of the annual review, the Emergency Management Director will schedule
a meeting and solicit comments and recommendations from City departments
82
including the City's first responders (Fire, Police and Public Works Departments),
subject matter experts and Tukwila residents and businesses. The current Plan
with updates will be posted for public comment on the City's website for at least
30 days. After the public comment period, the Emergency Management Director
will evaluate comments and recommendations and make the necessary changes.
Significant changes will be briefed to the City Council.
Section 201.6 of 44 Code of Federal Regulations (CFR), requires all jurisdictions
with an approved Hazard Mitigation Plan to review and revise its Plan and
resubmit it for approval within 5 years from the date of FEMA approval. The
Emergency Management Director will be responsible for carrying out the actions
required for the plan update. The actions required for the 5 -year plan update
will be similar to the annual update process described above but will follow a
more comprehensive process including but not limited to:
Assessment of Tukwila's hazard reduction goals and objectives.
Assessment of any changes to the hazards and risks that the hazards
pose to Tukwila residents, businesses and properties.
Evaluation of the progress in mitigation efforts /activities and changes in
priorities, funding or strategies.
Assessment of recent and future and changes in land development.
Assessment of changes to City critical infrastructure.
Assessment of resources required for plan implementation.
To accomplish the 5 -year plan update process, the Emergency Management
Director will follow a more formal plan update process by forming a team
(steering committee) consisting of Tukwila First Responder Representatives, City
department representatives, and subject matter experts (including State EMD,
FEMA, etc.) as required. Additionally, the Plan will be posted on the City's
website for at least 30 days for public review and comments. Once the Plan
updated is completed, it will go through a public process that includes
presentation to the Finance and Safety Committees and the Council for adoption.
During this process, the community will have more opportunities to provide
comments and input to the Plan. After Council approval, the Plan will be
forwarded to the State and FEMA for final approval.
As a regional partner, Tukwila will consider joining King County and other entities
in "adding on" to the King County Regional Hazard Mitigation Plan.
83
Emergency Management Council Attachment 1
November 16, 2009 10:30 a.m.
Conference Room #2
Meeting Minutes
Attendance: Not taken.
1. Update from Hillman:
a. Current weather does not indicate flooding risk
b. New Doppler units are being deployed
c. Corps and FEMA working on a decision support tool. Expected outcome is a
chart showing level of concern related to rainfall scenarios. Estimated
completion this week.
d. If power loss in 6300 building, phones and Nextel should work but email may
be out.
e. Hillman to provide a communication degradation protocol
f. Corps completed grout curtain and additional drains. Corps estimates a 1 in
25 chance for flood event.
g. Staff is working on budget request.
h. Hillman to work with WA State EMD re: city authority to raise revenue
2. Bob G update:
a. Looking for a "pay estimate" request from King County Flood Control District
b. Sandbags /HESCOs on left bank are 99% complete.
c. Sandbags /HESCOs on right bank still underway. 12 new culverts were
identified during the work and they may need valves /flapgates. Estimated
completion within 10 days (except flapgates).
d. Allentown flapgate should be installed this week.
e. Surveyed 5 areas this week including Gateway and Foster Point. Should
have map by end of week to assess what steps are needed.
3. Hillman
a. Response Plan Team is doing well on the plan.
b. Looking at buying 2 boats for response since the inflatable would be easily
damaged in flood response and have not found any mutual aid boats. Cost
for 2 around $100,000.
c. Will not activate "sand bag factory" at this time.
4. Foster Point Meeting
a. City to survey Foster Point properties and assess alternatives. May consider
HESCOs and sandbags along banks.
b. Approx 2/3 of homes are on septic, 1/3 on sewer. 60 homes total. Sewer
connection fee approx $30,000 per home.
c. Homes would be eligible for flood insurance.
5. Multi- Hazard Mitigation Plan
a. Draft plan is complete and will go to Council for approval soon.
Next Meeting: November 23, 2009 10:30 a.m. Conf Room #3
Minutes prepared by Derek Speck 11/20/09
84
Attachment 2
a
AGENDA
Foster Point Public Meeting
11/13/09
1. Introduction Hillman Mitchell
2. NW Hydraulics Model FP Hillman Mitchell
3. Tukwila Hazard Mitigation Plan Hillman Mitchell
4. Flood Preparedness Hillman Mitchell
5. License to Construct Hillman Mitchell
6. Q &A Department Heads
85
J ��11LAtv
s Attachment 3
0
Distribution: S. Hunstock D.Speck
o City of Tukwila D. Quinn M. Hart R. Still
A. Ekberg S. Kerslake D. Tomaso
s �2 Finance and Safety K. Hougardy K. Kertzman M. Villa
190 Committee D. Robertson T.
Mayor Haggerton K. MateKinlow j Judge Walden B. Arthur
O De'Sean Quinn, S. Lancaster M. Miotke C. Parrish
C. O'Flaherty G. Labanara K. Narog
Chair S. Brown D. Lincoln S. Kirby
O Allan Ekberg B. Giberson N. Olivas S. Norris
D. Haynes J. Pace
O Kathy Hougardy
AGENDA
WEDNESDAY, FEBRUARY 17, 2010
CONFERENCE ROOM #3; 5:00 PM
Item 1 Action to be Taken 1 Page
1. PRESENTATION(S)
2. BUSINESS AGENDA
a. Hazard Mitigation Plan; a. Information only. Pg.1
Frank Iriarte, Deputy Public Works Director.
b. 2009 Fourth Quarter Report b. Information only. Pg.3
c. Pre Retreat Budget Review c. Discussion. Pg.23
(please bring your budget books).
Next Scheduled Meeting: Tuesday, March 2, 2010
Committee Goals:
Work together in cooperation with nearby cities to address common problems in the Highway 99
corridor and Military Road.
Ensure a commitment to continued human services funding in relation to the cost of living
through consistent review of regional, state and federal budgets affecting human services
programs and services (also assigned to CAP).
Research the viability of sponsoring a City -wide Citizens' Academy (also assigned to CAP).
86
Attachment 4
►L s ti
Of y l
G1
DRAFT HAZARD MITIGATION PLAN
DRAFT TUKWILA HAZARD MITIGATION PLAN AVAILABLE FOR COMMENT Using
the guidelines provided by the Federal Emergency Management Agency (FEMA),
the City of Tukwila has developed a draft five -year Hazard Mitigation Plan with
the goal of reducing the impacts of natural, technological and man -made
disasters in the City.
The next steps are to:
1. Provide a public comment period.
2. Finalize the Plan.
3. Seek approval from FEMA.
The public is invited to view the draft plan and provide comments. The
comment period ends on Monday, March 15, 2010.
For more information or questions about the Plan, please call Frank Iriarte at
206 431 -2445.
View /Print the Draft Hazard Mitiaation Plan
Submit Comments on the Draft Hazard Mitiaation Plan
87
Attachment 5
DRAFT COPY
�J�.►J1LA tv4
01 ti Z
Q 1
Z 90a
CITY OF TUKWILA
WASHINGTON
RESOLUTION NO.
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF
TUKWILA, WASHINGTON, ADOPTING THE TUKWILA HAZARD
MITGATION PLAN
WHEREAS; the City of Tukwila and surrounding areas are subject to various
hazards including flooding, earthquakes, landslides, severe windstorms, and other
natural and technological /manmade hazards, and
WHEREAS; the City of Tukwila is committed to strengthening the City's resilience
to the effects of natural and technological /manmade hazards, and
WHEREAS; the federal Disaster Mitigation Act of 2000, specifically Section 322,
addresses local mitigation planning and requires local governments to develop Local
Hazard Mitigation Plans as a condition of receiving Hazard Mitigation Grant Program
funding, Flood Management Assistance, and Pre Disaster Mitigation funding from the
Federal Emergency Management Agency (FEMA) and
WHEREAS; FEMA has completed a pre- adoption review of the City's Hazard
Mitigation Plan and will approve the Plan upon receiving documentation of its adoption
by the City, and
NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF TUKWILA,
WASHINGTON, HEREBY RESOLVES AS FOLLOWS:
88
Section 1. The City Council approves participation in the hazard mitigation
planning process, development of a City -wide Hazard Mitigation Plan, and adoption of
the final FEMA- approved Hazard Mitigation Plan.
PASSED BY THE CITY COUNCIL OF THE CITY OF TUKWILA, WASHINGTON, at a
Regular Meeting thereof this day of 2011.
Allan Ekberg, Council President
ATTEST /AUTHENTICATED:
Christy O'Flaherty, CMC, City Clerk
APPROVED AS TO FORM BY:
Filed with the City Clerk:
Passed by the City Council:
Office of the City Attorney Resolution Number:
89
LAND USE ZONING MAP ATTACHMENT 6
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90
POTENTIAL FLOOD AFFECTED AREAS ATTACHMENT 7
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City of Tukwila
Potential Rood Affected Areas
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Cate: September 28, 2009
91
Tukwila Critical Facilities Inventory Attachment 8
Maximum Facilities Not
Critical Facility Jurisdiction Controlled Loss Controlled under
Type Facilities Facilities Jurisdiction
Control
*City Hall Complex 8.3M
(Includes Police, EOC
Continuity of Court)
Government or *Building 6300 Complex 5.3M
Administration (Includes Public Works,
DCD, Police, Personnel
IT Dept)
*Fire Stations:
51, 52, 53, 54 8.4 M
*Police Equipment 250K
Communications *Fire Equipment 250K
*IT Equipment
*City Telephone 250K
*Arterial /Collector Streets 980K
Transportation *Local Streets 30M
*Bridges 60.5M
*Foster High School 17.7M Tukwila School
Education *Showalter Middle School 15.3M District
*Cascade View Elementary 9.3M
*Thorndyke Elementary 10.8M
*Tukwila Elementary 10.8M
*City Water Reservoir 4.8 M
Utilities *Sewage lift Stations 2.3 M
*Surface Water Lift 3.4 M
Stations
Community Services *Tukwila Community 9.2 M
Center
Maintenance shops *Minkler Shops 3.7M
*George Long Shops 2.3M
92
HAZARD MITIGATION PLAN INITIATIVES Attachment 9
Jurisdiction Aaencv: City of Tukwila Emergency Management
Tyne of Hazard: Earthquake, Severe Winter Storm, Flooding, Landslide and other
hazards including Volcanic Eruption, Urban Fire, Tornado, and Drought.
Category: Permanent City Emergency Operations Center
Priority: 1
Brief Description of Project: Construct a new City Emergency Operations Center (EOC)
facility to support emergency response and recovery coordination.
Rationale for Project: The City's EOC is located in the Police Department Training Conference
Room. The facility is small and cannot accommodate all the anticipated EOC functions and
personnel needed to manage a protracted emergency event and support the City's Continuity of
Operations Plan (COOP).
RHMP Goals: 1. Protect Life and Property 3. Support Emergency Services
2. Enhance Planning Activities
Lead Jurisdiction: City of Tukwila Public Works Participating Jurisdictions: None
Cost of Project: $1,250,000
Estimated time period Implemented: Beyond 2014
Funding Sources: City Operating Revenue; Grants
Source and Date: City of Tukwila 2009 -2014 Financial Planning Model /Capital
Improvement Program.
Adoptive date and /or Ordinance /Resolution December 15, 2008; Resolution 1674
Status: New project
Benefit /Cost Ratio: 1.8:1 ($2.3 million planning figure from King County Regional
Hazards Mitigation Plan for at least one life saved divided by construction cost).
93
HAZARD MITIGATION PLAN— INITIATIVES Attachment 10
Jurisdiction Aaencv: City of Tukwila Emergency Management
Tvoe of Hazard: Earthquake, Flooding, Urban Fire, Drought and other hazards.
Category: City Maintenance Facility Replacement Project
Priority: 2
Brief Description of Project: Construct new City maintenance and operations center to
support critical City functions including fleet services, facilities maintenance, water, sewer,
surface water, streets and traffic control operations.
Rationale for Project: The City's current facilities, fleet and maintenance shops are
inadequate to support and restore essential services following a significant emergency event.
The shops currently don't have emergency power and have failed seismic evaluations
performed by a certified structural engineering firm in August 2008. A new City Maintenance
and Operations facility would allow continuity of operations under emergency conditions for
an extended period of time.
Goals: 1. Protect Life and Property 3. Support Emergency Services
2. Enhance Planning Activities
Lead Jurisdiction: City of Tukwila Public Works Participating Jurisdictions: None
Cost of Project: $10,000,000
Estimated time period Implemented: Beyond 2014
Funding Sources: City Operating Revenue and bond
Source and Date: City of Tukwila 2009 -2010 Financial Planning Model /Capital
Improvement Program
Adoptive date and /or Ordinance /Resolution: December 15, 2008; Resolution 1674
Status: New project
Benefit /Cost Ratio: .55:1 ($5,575,000 retrofit cost divided by $10M replacement cost).
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HAZARD MITIGATION PLAN INITIATIVES Attachment 11
Jurisdiction Aaencv: City of Tukwila Emergency Management
Tvoe of Hazard: Earthquake
Cateaory: Boeing Access Road Bridge Replacement
Priority: 3
Brief Description of Project: Replace the existing bridge with a 340' long concrete or steel
bridge structure. Bridge will be 110' wide curb to curb with sidewalks on both sides.
Rationale for Project: The existing bridge is structurally and seismically deficient. Several
pedestals are leaning and have concrete spalls, exposed rusty anchor bolts /reinforcements and
some cracks. The existing railings do not meet standards. The Boeing Access Road Bridge is
a major east west arterial that provides access between East marginal Way and the I -5
corridor. Bridge failure will severely impact freight mobility, and threaten public safety.
Goals: 1. Protect Life and Property 3. Support Emergency Services
2. Enhance Planning Activities
Lead Jurisdiction: City of Tukwila Public Works Participating Jurisdictions: None
Cost of Project: $30,000,000
Estimated time period Implemented: 2 -5 years
Funding Sources: Federal Funds; Bonds; City Operating Revenue
Source and Date: City of Tukwila 2009 -2014 Financial Planning Model /Capital
Improvement Program
Adoptive date and /or Ordinance /Resolution December 15, 2008; Resolution 1674
Status: New project.
Benefit /Cost Ratio: .70 ($21 million cost to repair /retrofit divided by the $30 million
replacement cost).
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HAZARD MITIGATION PLAN— INITIATIVES Attachment 12
Jurisdiction Agency: City of Tukwila Emergency Management
Tyne of Hazard: Landslide, Severe Weather, Flooding, and Earthquake
Category: Interurban Ave South Project- Wall Containment
Priority: 4
Brief Description of Project: Construct a concrete containment wall (4' high by 275'
long) along the west side of Interurban Avenue South.
Rationale for Project: During severe winter storms, landslides have occurred on the steep
hillside along the west side of Interurban Avenue. Construction of the containment wall will
prevent landslide debris from blocking the traffic lanes of Interurban Avenue which serve as a
principal arterial for over 20,000 motorists. Containment wall will also enhance the safety of
motorists and pedestrians.
Goals: 1. Protect Life and Property 3. Support Emergency Services
2. Enhance Planning Activities
Lead Jurisdiction: City of Tukwila Public Works Participating Jurisdictions: None
Cost of Project: $500,000
Estimated time period Implemented: 2 -5 years depending on availability of grant funds.
Funding Sources: City Operating Funds; Grants
Source and Date: City of Tukwila 2009 -2014 Financial Planning Model /Capital
Improvement Program
Adoptive date and /or Ordinance /Resolution December 15, 2008; Resolution 1674
Status: New Project
Benefit /Cost Ratio: At least a 1:1 ratio due to clean up costs and financial impact on
businesses in the Commercial Business District.
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