2
SUTD Master of Architecture Thesis Document Wildfire Architecture: Design for adaptive resilience
Acknowledgements First and foremost, I would like to thank my thesis advisor Peter Ortner for his valuable insights and guidance, without which this thesis book would not have been possible. I would also like to thank my friends for the (virtual) support and motivation throughout this unique semester. Writing an architecture thesis in the midst of a global pandemic would not have been this enjoyable without our late night conversations that have kept me sane. Finally, this book is dedicated to my parents, for their encouragement and support over the past few months and beyond.
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Contents Page 0
ABSTRACT
6-7
1
INTRODUCTION
8-18
1.1
Wildfire & Architecture
2 ON WILDFIRE RESILIENCE: THE RESEARCH HYPOTHESIS 2.1 2.2 2.3
3 3.1 3.2 3.3 3.4 3.5
4
4.1 4.2 4.3
4
19-40
Discussing wildfire resilience Redefining wildfire resilience Research Methodology: Steps to investigating the adaptive resilience model
CALIFORNIA: A STATE IN FLAMES
41-68
A history of California’s wildfire crisis The role of wildfires in the Californian ecosystem Suburbanisation & the American Dream California’s Housing Crisis Existing approaches towards wildfires
WILDLAND-URBAN INTERFACES (WUI): STRATEGIES FOR THE U RBAN LANDSCAPE Understanding WUIs WUI typologies: Interface, Intermix and Occluded conditions, The Urban-to-Rural Transect The dichotomy of urban strategies in planning for WUIs
69-90
5 5.1 5.2 5.3
6
6.1 6.2 6.3
CONSTRUCTING FOR WILDFIRE
91-118
Wildfire support infrastructure Housing in suburban California Adaptive architecture: ideas for wildfire adaptive
DESIGN FOR A NEW FIRE-RESILIENT COMMUNITY
119-142
Why Paradise? Extracting research insights Rebuilding Paradise: deriving an architectural solution
7 CONCLUSION
143-144
8
FINAL DESIGN
145-158
9
BIBLOGRAPHY & APPENDIX
5
Abstract The allure of the idyllic suburban life, a lower cost of living, and rising housing costs in developed cities has driven many homeowners to build further away into the urban fringes. Urban habitats and natural landscapes are becoming increasingly intermixed, accompanied by an elevated risk of wildfires capable of devastating entire towns and communities. 1 This thesis takes a critical relook at wildfire resiliency by first understanding the wildfire crisis in the Californian context, where the pursuit towards aggressively fortifying urban habitats has become the modus operandi. Current fire resilient approaches are focused on reactive strategies such as rebuilding with fire resistant materials and minimising natural vegetation around urban infrastructure. While useful in fire prevention, such methods of designing against nature dilutes the intimate human-nature relationships that are unique and valuable to urban-wildland communities. It also renders these communities ill-equipped to recover in the worst-case scenario of an actual disaster. By looking at the limitations of existing solutions, fundamental ideas behind wildfire resilient design will be challenged; stakeholders are urged to consider the premise of wildfire inevitability when designing for resiliency, a proposition that is becoming an increasing reality in today’s climate. As opposed to solely seeking measures that avoids destruction at all costs, a new architectural design paradigm focused on adapting to destruction and recovery is proposed. In designing for adaptive resilience, communities are able to rebuild in a way that iteratively strengthens their position against future fires.
6
7
8
Introdu ction
1
INTRODUCTION
In tro d uc tio n
9
1.1
Wildfire & Architecture
premise of embracing the cycle of destruction as opportunities for adaptibility and growth as the more constructive way forward, not just in California but in other wildfire-striken communities all over the world.
From earthquake resistant structures to floating, flood-proof cities, architecture has done it all when it comes to creating built environments able to withstand the unrelenting forces of nature‌ Or has it? While natural disasters such as hurricanes, floods, and earthquakes have been pondered over with numerous visionary design solutions 2, wildfires as an equally pertinent environmental challenge has yet to be met with the same level of enthusiasm. This grave lack of urgency and attention paid to the wildfire crisis relates to a tendency to view wildfires as a preventable, man-made phenomenon: despite being classified by the Environmental Protection Agency of the United States as a natural disaster, only 10-15 percent of wildfires actually occur spontaneously in nature. The remaining majority are a result of human causes, such as exposed power lines or unattended campfires. 3 However, that is not to say that wildfires are any less critical in our ongoing dialogue for resilient urban planning and architectural design. In fact, wildfires are greater threats to cities and fire-prone communities worldwide as compared to typical natural disasters. In 2018, the state of California alone suffered USD $400 billion worth of fire damages 4, 8 times that of the country-wide hurricane damages over the same time period. 6 By referencing California, the American state under the highest wildfire risk 7, this book will look into how, why and when wildfires occur, wh y they are here to stay, and what this entails for fire-prone urban communities. In questioning the fundamental ideas of resilience and the reflexive approach of recouping and rebuilding after a destructive loss, chapters will navigate the alternative
10
Introdu ction
Wildfires are growing larger and more frequent Right: California’s historical fire perimeters sorted by year & area Data compiled of historic fire perimeters o v e r t h e p a s t 10 y e a r s have indicated a clear increase in fire magnitude5
2010
2011
2012
70 - 1 1 4 0 7 84 5 69
41 - 1140 784569
7 0 - 162 87 314 7
In tro d uc tio n
11
2013
2014
41 - 1140 78456 9
391 - 36355664 6
In tro d uc tio n
12
2015
2016
144 - 6 20 52756 7
4 0 - 114 07 84 569
In tro d uc tio n
13
2017
2018
70 - 1 1 407 84 5 69
7 1 - 33113894 9
In tro d uc tio n
14
15
Introdu ction
An increasing number of people are residing in high wildfire risk areas
Map of wildlifeurban interface regions in California, demarcating areas containing urban populations at elevated risk of wildfires
1/3 of California’s population are classified under “very high or extreme fire threat” communities8
In tro d uc tio n
16
Current solutions are not preparing communities for future wildfire trends
17
Introdu ction
With climate change, California’s annual burned area have increased five fold since 1972 9 Fires are growing larger, less predictable, and more destructive. The extent of losses from wildfires in recent years have shown that typical responses to wildfires have yet to repond to these trends which demand for communities to grow, adapt, and recover from wildfire disasters of greater intensities. 10
Wildfires are essential to ecosystems, ecosystems are essential to communities Forest ecosystems in California have a natural fire cycle which helps forests grow and rejuvenate. At the same time, the natural environment provided by these forests plays an integral role in the livability & sustainability of wildland-urban interface communities. 11
Cities are running out of space Increasing desification and rising costs of cities have driven home owners to relocate to suburban areas, elevating wildfire risks as well as the number of people subjected to these risks. 12
. . . Where is the middle ground? Can settlements truly be wildfire resilient?
In tro d uc tio n
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19
O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
2
ON WILDFIRE RESILIENCE: THE RESEARCH HYPOTHESIS
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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2.1 Discussing Wildfire
Resilience In placing the idea of wildfire resilience in context, this chapter begins with a look at one of California’s largest and most destructive fire. The 2018 Camp Fire occured during one of California’s hardest hit fire seasons, ravaging through the town of Paradise on November 8th. Leaving 86 deaths and destroying 95% of homes and businesses in its wake, the town which was home to a quiet community of middle and lower income Americans was almost completely decimated over the course of 17 days. 13 One year on, Pardise’s response towards the aftermath of a wildfire this extensive has revealed the stark inadequacy in disaster recovery for an average American town: even as much of the vegetation has regrown, the rubble of a burnt McDonalds restaurant, the sooted metal of abandoned cars, and a largely displaced population remains. 14 Nature’s resilience has clearly outpaced our own, beckoning the question of what went wrong, and what more can be done in terms of a community’s wildfire resiliency. 15
Legend: -
Ve g e tat i o n Fa rmla n d Re ma in i n g bu i l d i n g s a f t e r t he wi l dfi re Bu ild in g s d e st r o y e d
Map of Paradise, before & after the 2017 Camp Fire Plan, 1:25000
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
McDonald’s on Clark Road, Paradise, CA Before & After Camp F i r e 16
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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What is wildfire resilience? Paradise’s struggle to regroup after the Camp Fire shows that it has much to work on in terms of wildfire resiliency. Resilience, a central concept in the field of ecology, is broadly defined as the ability of a system to recover after stress or disturbance. 17 Along the same vein, wildfire resilience refers to the ability of a community to withstand a fire disaster without significant interruptions to its social and economic routines. As a design aspiration, wildfire resilience is a multifaceted one. Current approaches towards resilience can be deconstructed into three key components that characterises a fire-resilient community to be one that has 1. successfully minimised wildfire risks, 2. optimised disaster responses, and 3. is fast recovering. This can be achieved through interventions at various scales, ranging from urban to architectural.
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
I. MINIMISING RISK
The ability of a community in minimising controllable wildfire risks
• Design/Construction of infrastructure • Living conditions of marginalised Vulnerability
• Human activities with fire risk conducted near wildland
Exposure
II. DISASTER RESPONSE
communities (e.g. homeless encampments)
• Degree of community awareness • Landuse planning for wildfires
• Landscape planning - management of wildland vegetation/fuel
The effectiveness of a community in disaster monitoring, conveying essential information, as well as the level of preparedness of residents in reacting to a variety of wildfire scenarios.
• Responsiveness of monitoring and alert Support Infrastructure
systems
• Accessibility/Location of fire response services to the site of fire
Ease of evacuation
• Population/housing density • Means of ingress/egress, minimum evacuation time
III. DISASTER RECOVERY
The effectiveness of a community to recoup infrastructural losses, economy function, and restore normalcy in daily routine.
Maintaining essential services/infrastructure operation
• Ability of essential infrastructure (e.g.
power supply) to withstand fire damage
• Strategic location of essential infrastructure • Rate of reassembly
Ease of reconstructing
• Availability of post-disaster support Recovery Resources
infrastructure to all residents (e.g. Wildfire shelters, access to rebuilding materials)
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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Paradise’s geography between two densely vegetated canyons places it at high risk of a wildfire
Buildings at urban core formed the bulk of buildings that survived the wildfire Skyway road, the main escape thoroughfare became a bottleneck as residents rushed to drive out of town
Extreme winds created spot fires all over Paradise by blowing embers far into the town
Legend: - Residential - Recr eation - Civic bu ildings - Religiou s bu ildings - Health car e - Sch ools - Hotel - Retail/Commer cial - Amenity - Indu str ial
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
Where did Paradise go wrong? A map of Paradise post Camp Fire, colour coded to building use types
I. ASESSING RISK
III. DISASTER RECOVERY
Paradise was home to 26,000 Americans, many of which were seniors, retirees and low to middle income families with homes along forested roads 17, driven away from the larger cities by escalating living and housing costs. This has resulted in a growing urban density within forested land, elevating wildfire risks.
Most towns are equipped with response plans when met with a wildfire, but few have plans drawn out for recovery. Paradise is no exception - 6 months after the fire, only 2000 out of the 26,000 residents came back to the town. The town committee shortly released a recovery plan, which detailed new building regulations with higher construction costs that instead deterred residents from rebuilding. 19
On top of that, wildlands adjacent to Paradise had faced periods of droughts prior to the Camp Fire, littering the ecosystem with dried up and highly combustible vegetation 18 and placing the town at high risk of fires. II. DISASTER RESPONSE
There are only two main thoroughfares running through the town and between the two canyons - Skyway Road and Clark Road. For a town with 26,000 residents, this is inadequate and provides little to no vehicular accessibility for fire fighting resources to reach the affected areas. 18
To date, the pace of reconstruction is slow, and redevelopment has taken on the form of random, disorganised sprawl as selective homeowners returned to rebuild in their housing lots while others sold their land for redevelopment. Many business also lack the incentive to return due to a small population and insufficient demand.
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
Was Camp Fire inevitable? From photo along Camp
t h e N e w Yo r k T i m e s of residential area skyway road after Fire
Paradise was not entirely unprepared for the Camp Fire - evacuation plans were drawn out and escape routes charted in the event of such a disaster. However, the volatile and unpredictable nature of wildfires prevailed, throwing a wrench in Paradise’s response plans as flames engulfed the town in a random, unforseen manner. A look at Paradise post-disaster reveals that the bulk of the buildings which survived the wildfires were concentrated at the urban core, where vegetation is sparse. The buildings which occupy these areas are of the industrial and commercial types, while the majority of residential homes were decimated. The architecture which had survived the flames did so by chance rather than preparedness - the lower fire risk of urbanised regions combined with the nature of industrial and commercial buildings made of less combustible materials such as concrete had allowed these buildings to escape relatively unscathed, highlighting the challenges and inadequacy of approaching wildfire resilience solely via a hyper defensive approach that only addresses risk management (1) and disaster response (2) approach without considering for recovery (3).
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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2.2
Redefining
Are wildfires the new normal?
wildfire resilience
With fires as devastating and unpredictable as the Camp Fire, as well as current trends pointing towards higher frequencies of wildfires in the forseeable future, there is a need to start designing with the assumption of them being a new normal in high risk communities. This is to ensure that populations are prepared to recover from worst case scenarios, on top of prevention and response as baseline measures. Assuming the inevitability of wildfires means adapting to elements of predictable fire behaviour, capitalising on the cycle of destruction and recovery to improve resiliency, and developing regenerative frameworks on an urban and architectural scale. 155 150 145 140 135 130 125 120 115 110
n umber of wildfire s
105 100 95 90 85 80 75 70 60 55 50 45 40 35 30 25 20 15 10 5 0 1 2 3 4 5 6 7 8
2013
9 10 11 12
1 2 3 4 5 6 7 8
2014
9 10 11 12
1 2 3 4 5 6 7 8
2015
9 10 11 12
1 2 3 4 5 6 7 8
9 10 11 12
2016
1 2 3 4 5 6 7 8
9 10 11 12
1 2 3 4 5 6 7 8
2017
da te (month )
NUMBER OF WILDFIRES IN CALIFORNIA VS. TIME Predictive cyclical wildfire patterns: California experiences seasonal wildfires - Peaks in the months of June to September can be observed from fire data f r o m 2 0 1 3 - 2 0 1 9 20
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
2018
9 10 11 12
1 2 3 4 5 6 7 8
2019
9 10 11 12
... Missing links in existing resilience strategies? Conventional wildfire resilience; a linear model where strategies targeted at wildfire resilience are applied independently of contextual patterns and past fire events Examples include: rebuilding with fire resistant materials on a site that has been repeatedly struck by wildfires, cutting down vegetation in surrounding areas after a wildfire
I. MINIMISING RISK PRE-WILDFIRE SEASON April - June
in the worst case scenario of a wildfire...
In particular instances where wildfires were unable to be contained and controlled effectively, many communities such as Paradise have been hindered by the lack of a centralised recovery plan, recovering in a linear, reactive way that only focuses on reverting to the pre-fire status quo. The almost militaric insistence to physically rebuild without properly addressing the vulnerabilities exposed by the disaster results in a response that fails to future proof communities against subsequent fires. At best, conventional resilience retains the level of resilience a community started out with prior to a wildfire. In reality, the growing intensity of wildfires today makes the act of retaining resilience insufficient in protecting vulnerable communities from future threats.
II. DISASTER RESPONSE WILDFIRE SEASON July - September
I. MINIMISING RISK POST-WILDFIRE SEASON January - March
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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If retaining resilience is not enough, then a better solution would involve building resilience after each wildfire. With this objective comes the distinction between ideas of adaptive resilience vs. conventional resilience:
Moving forward with a new paradigm A cyclical approach with an additional dimension of time a feedback loop is formed where fire occurrences inform future strategies adopted after a disaster, so as to improve the resilience of a wildfire prone community
While adaptive resilience results in wildfireadapted communities that gain resilience from each wildfire disturbance, wildfireresistant communities of conventional resilience models only retains existing levels of resilience after every wildfire (which as previously mentioned, is inadequate since wildfires are getting larger and more frequent). Adaptive resilience creates a feedback loop that is missing from the conventional resilience model - information gleaned from each process of the destruction-recovery cycle of a wildfire disaster is used to inform subsequent steps taken to positively improve a community’s level of resilience, allowing resilience to grow and adapt to rising wildfire threats.
evaluating new information
EVALUATE
data of vulnerabilities exposed by latest wildfire occurence
GOAL SENSE
building wildfire resilience
ENVIRONMENT in the worst case scanerio of a wildfire ...
added wildfire resiliency to community
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
ACTION
decision on strategies employed
PRE-WILDFIRE SEASON
WILDFIRE SEASON
POST-WILDFIRE SEASON
April - June
July - September
January - March
1 Architecture in wildfire prone communities
7 Adaptation & Reconfiguration for improved resiliency
2 Disassembly & Reconfiguration before wildfire season
6 Rapid Reassembly
3 Adapted forms/ functions for Wildfire Seasons
4 Wildfire scenario
5 Remnants of a permanent, fire resistant structural shell
How might adaptive resilience look like? Above: conceptual illustration of adaptive resilience on a building scale
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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identifying new high wildfire risk zones & wildfire patterns
Pre-Wildfire Season I. MINIMISING RISK
extent & location of fire damage, duration between fires, landscape conditions
EVALUATE REDUCING FREQUENCY OF WILDFIRES
SENSE event of redisturbance
ENVIRONMENT
identifying response & evacuation bottlenecks
EVALUATE Wildfire Season II. RESPONSE/ DESTRUCTION
response time, evacuation efficiency, human injuries/casualties
SENSE
REDUCING WILDFIRE LOSSES
event of redisturbance
ENVIRONMENT
updating construction/ material/technological abilities
EVALUATE Post-Wildfire Season III. RECOVERY
time & cost taken to rebuild, for normal function to be restored
SENSE
REDUCING RECOVERY TIME & COST
event of redisturbance
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
ENVIRONMENT
ACTION
targeted risk reduction strategies
flexible programmatic uses
targeted areas for forest management strategies (ie. prescribed burns)
defensible architecture
ACTION
streamlining wildfire response strategies
There are three key elements to wildfire resiliency (see section 2.1): 1. minimising risk, 2. optimising disaster response, and 3. expediting recovery. An adaptive resilience model builds on these three basic concepts of risk, response and recovery, in three corresponding feedback loops. The feedback loop model follows the structure of a cybernetics loop 20 - an existing design of a system is executed, its efficacy evaluated based on information sensed from the system environment (in this case the urban community after a wildfire occurrence), and is redeveloped and executed again. This self-improving iterative model forms the basis of a wildfire adaptive community that has the capacity to improve its resilience indefinitely.
Each of the three parallel functioning feedback loops form the complete picture of an annual wildfire season in California:
• The risk minimising loop targets
strategies for pre-wildfire season to prevent wildfires
where to rebuild redistribution of building densities to optimise evacuation movement/networks
• The disaster response loop targets strategies for wildfire season in minimising wildfire losses
• The recovery loop targets strategies
for post-wildfire season to facilitate rebuilding
fire-proof structural frame for rapid assembly
ACTION
improving recovery strategies
modular, fire resistant building components
fire-proofing key public infrastructure
Parallel feedback loops for future wildfire adapted communities O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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The increased interaction between urbanism and nature in recent years have created what ecologists regard as inherently dynamic systems - systems in which attempts to exert stability are largely futile. 21 As opposed to existing ideas of resilience that aims at “stablising� a community ecosystem by absorbing the effects of wildfires, adaptive resilience accepts the inherent unpredictability of fires as a natural disaster, recognises the limitations of past and existing solutions, and respects the important role of wildfire in maintaining many ecosystems and ecosystem services. In doing so, adaptive resilience embraces destructive-recovery cycles of wildfires to inform improvements in wildfire resiliency on both an urban and architectural scale. While ideas on adaptive resilience with regard to the wildfire crisis have been discussed in terms of forest ecology and legislative policies 22 23, this thesis looks at starting a conversation on adopting the concept of adaptive resilience from a urban/ architectural design perspective.
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
Key ideas of adaptive resilience
1 Accepting instead of resisting the growing threat wildfires pose to urban communities Based on current realities, designing with the informed assumption of wildfires as a default, inevitable problem for communities located near wildland could be a more sensible approach.
2 A feedback loop: past wildfires inform adaptations to improve future wildfire resilience Wildfires might be a natural disaster with detrimental consequences, but that does not mean that communities cannot benefit from it. The benefit of an adaptive resilient model lies in the feedback loop, where communities stand to gain from the information revealed through a wildfire disturbance. Approaches should be adaptable to the added dimension of time, and should constantly be informed by current conditions in a feedback loop across the destruction-recovery cycle.
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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2.3
Research Methodology
1 DEFINING THE PROBLEM
+
2
3
UNDERSTANDING KEY CONCEPTS OF WILDFIRE RESILIENCE
IDENTIFYING BENEFITS & LIMITATIONS OF EXISTING STRATEGIES
This book will first seek to understand the current climate of wildfires in California in Chapter 3, accumulating an information bank that would help establish cause for an alternative approach. Chapters 4 & 5 would hinge on the idea of adaptive communities and explore potential solutions using a combination of data mapping and analysis.
III. DISASTER RECOVERY
Finally, Paradise, California, as the choosen site of the prototype town, will be used to demonstrate the derived strategies. Chapter 6 provides preliminary design insights with Paradise as the site context, where potential benefits and limitations will be speculated in detail.
Chapter 3: Califonia: A State in flames
Ultimately, this thesis aims to formulate in a strategic manner an updated resilience proposal that would inform designers of the steps neccessary in building future wildfireadapted communities.
II. DISASTER RESPONSE
I. MINIMISING RISK
Steps to investigating the adaptive resilience model
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O n Wildfire Resilie n c e : The R e se a r c h H yp ot he si s
Fire Forcasting Vulnerability
Wildfire building codes Fire supression Exposure
Prescribed burns
Ease of evacuation
Response/ Evacuation Plans
Support Infrastructure
Fire Fighting protocols/ infrastructure
Maintaining essential infrastructure operation
Rebuilding, fireproofing essential infrastructure
Ease of reconstructing
-
Recovery Resources
-
5
6
ESTABLISHING CAUSE FOR AN ALTERNATIVE APPROACH
PROPOSAL FOR A NEW SOLUTION: ADAPTIVE RESILIENCE
URBAN/PLANNING STRATEGIES
REDUCING RECOVERY TIME & COST
REDUCING WILDFIRE LOSSES
REDUCING WILDFIRE FREQUENCY
4
+
7
8
ARCHITECTURAL STRATEGIES
DEMONSTRATION OF PROPOSED STRATEGIES
flexible programmatic uses targeted areas for forest management strategies (ie. prescribed burns) defensible architecture where to rebuild - redistribution of building densities to optimise evacuation movement/ networks
Chapter 4: Wildland-Urban interfaces (WUI): strategies for the urban landscape
Chapter 5: Constructing for wildfire
Chapter 6: Design for a new fire resilient community
fire-proof structural frame for rapid assembly
modular, fire resistant building components fire-proofing key public infrastructure
O n W il d f ire R e s il ie n c e : T h e R e s e a rc h H y p o th e s is
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41
Calif ornia: A state i n f l a me s
3
CALIFORNIA: A STATE IN FLAMES
C a l if o rn ia : A s ta te in f l a m e s
42
3 .1
A History of California’s wildfire crisis All 10 of the costliest fires of the United States have occured in California 24, which have been historically known as the state most affected by the wildfire problem due to its abundance of forested landscapes. Compounded with the effects of climate change which have elevated overall temperatures, California’s fires have only gotten more frequent and extensive over the years. The job of understanding the different facets of the wildfire crisis is complex, and forms the basis of a holistic proposal for building wildfire resiliency. This is not a problem unique to America or California, but California is choosen as the site of reference because of its long-standing relationship with managing wildfires that have been extensively documented over the years. The wealth of historical, social and geographical data will be highly constructive as a starting point of this book’s venture towards a holistic solution, as would be demonstrated in the following chapter.
Looking at historical wildfire footprints in California There are few places left untouched by wildfires in California. The map shows a 9 year history of land that have been burned by wildfires across the state. The 4 most destructive fires in California have been identified in the same map, all of which have occured within the recent 9 - y e a r t i m e f r a m e . 24
43
Calif ornia: A state i n f l a me s
2018 CAMP FIRE Deaths: >86 Structures destroyed: 18,804 Area: 621km 2 2017 TUBBS FIRE Deaths: 22 Structures destroyed: 5,643 Area: 149km 2
2017 THOMAS FIRE Deaths: 2 Structures destroyed: 1,063 Area: 1140km 2
2000
2018 WOOLSEY FIRE Deaths: 3 Structures destroyed: 1,643 Area: 392km 2
2018
C a l if o rn ia : A s ta te in f l a m e s
44
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
What causes wildfires? A visual composition of wildfire causes in California, from 2000 2016
Natural causes eg. lightning, volcanic
45
2017
Misc/Unknown causes
Calif ornia: A state i n f l a me s
2018
Human Activities eg. arson, burning debris, smoking
t o 2 0 1 8 25
Passive Causes eg. Infrastructure : Railroads, powerline
Fire fighting & other personel trainings
0.089005 0.450262 0.34555 0.109948 0.005236 0.089005 0.450262 0.34555 0.109948 0.005236 0.089005 0.450262 0.34555 0.109948 0.005236 0.089005 0.139194 0.450262 0.285714 0.34555 0.450549 0.109948 0.120879 0.005236 0.003663 0.089005 0.139194 0.450262 0.285714 0.34555 0.450549 0.109948 0.120879 0.005236 0.003663 0.139194 0.285714 0.450549 0.120879 0.003663 0.139194 0.576744 0.285714 0.172093 0.450549 0.167442 0.120879 0.083721 0.003663 0 0.139194 0.576744 0.285714 0.172093 0.450549 0.167442 0.120879 0.083721 0.0036630 0.576744 0.172093 0.167442 0.083721 0.5767440 0.165242 0.172093 0.467236 0.167442 0.301994 0.083721 0.0655270 0 0.576744 0.165242 0.172093 0.467236 0.167442 0.301994 0.083721 0.0655270 0 0.165242 0.467236 0.301994 0.065527 0.1652420 0.073864 0.467236 0.556818 0.301994 0.238636 0.065527 0.1306820 0 0.165242 0.073864 0.467236 0.556818 0.301994 0.238636 0.065527 0.130682 00
2000
2004
2008
2012
0.073864 0.556818 0.238636 0.130682 0.0738640 0.556818 0.238636 0.130682 0 0.073864 0.556818 0.238636 0.130682 0
0.193237 0.26087 0.396135 0.130435 0.019324 0.193237 0.26087 0.396135 0.130435 0.019324 0.193237 0.26087 0.396135 0.130435 0.019324 0.193237 0.219595 0.26087 0.287162 0.396135 0.327703 0.130435 0.165541 0.019324 0 0.193237 0.219595 0.26087 0.287162 0.396135 0.327703 0.130435 0.165541 0.019324 0 0.219595 0.287162 0.327703 0.165541 0.2195950 0.266932 0.287162 0.350598 0.327703 0.258964 0.165541 0.1235060 0 0.219595 0.266932 0.287162 0.350598 0.327703 0.258964 0.165541 0.123506 00
2001
2005
0.266932 0.350598 0.258964 0.123506 0.2669320 0.187919 0.350598 0.45302 0.258964 0.265101 0.123506 0.093960 0 0.266932 0.187919 0.350598 0.45302 0.258964 0.265101 0.123506 0.093960 0
2009
0.187919 0.45302 0.265101 0.09396 0.1879190 0.220758 0.45302 0.46458 0.265101 0.189456 0.09396 0.1252060 0 0.187919 0.220758 0.45302 0.46458 0.265101 0.189456 0.09396 0.125206 00
2013
0.220758 0.46458 0.189456 0.125206 0.2207580 0.46458 0.189456 0.125206 0 0.220758 0.46458 0.189456 0.125206 0
2016
= natural causes
2017
+
0.115226 0.304527 0.436214 0.144033 0 0.115226 0.304527 0.436214 0.144033 0 2002 0.115226 0.304527 0.436214 0.144033 0.1152260 0.404459 0.304527 0.238854 0.436214 0.251592 0.144033 0.1050960 0 0.115226 0.404459 0.304527 0.238854 0.436214 0.251592 0.144033 0.1050960 0 0.404459 0.238854 0.251592 0.105096 0.4044590 2 0 0 6 0.235577 0.238854 0.346154 0.251592 0.322115 0.105096 0.0961540 0 0.404459 0.235577 0.238854 0.346154 0.251592 0.322115 0.105096 0.096154 00
0.407625 0.190616 0.293255 0.102639 0.005865 0.407625 0.190616 0.293255 0.102639 0.0058652 0 0 3 0.407625 0.190616 0.293255 0.102639 0.005865 0.407625 0.237822 0.190616 0.340974 0.293255 0.312321 0.102639 0.108883 0.005865 0 0.407625 0.237822 0.190616 0.340974 0.293255 0.312321 0.102639 0.108883 0.005865 0 0.237822 0.340974 0.312321 0.108883 0.23782202 0 0 7 0.221519 0.340974 0.351266 0.312321 0.303797 0.108883 0.1234180 0 0.237822 0.221519 0.340974 0.351266 0.312321 0.303797 0.108883 0.123418 00
0.235577 0.346154 0.322115 0.096154 0.2355770 0.32618 0.346154 0.377682 0.322115 0.193133 0.096154 0.103004 0 0 2010 0.235577 0.32618 0.346154 0.377682 0.322115 0.193133 0.096154 0.103004 00
0.221519 0.351266 0.303797 0.123418 0.2215190 0.360656 0.351266 0.327869 0.303797 0.209836 0.123418 0.101639 0 02 0 1 1 0.221519 0.360656 0.351266 0.327869 0.303797 0.209836 0.123418 0.101639 00
0.32618 0.377682 0.193133 0.103004 0.326180 0.095122 0.377682 0.565854 0.193133 0.229268 0.103004 0.1097560 0 0.32618 0.095122 0.377682 0.565854 0.193133 0.229268 0.103004 0.1097560 0 2014 0.095122 0.565854 0.229268 0.109756 0.0951220 0.565854 0.229268 0.109756 0 0.095122 0.565854 0.229268 0.109756 0
0.360656 0.327869 0.209836 0.101639 0.3606560 0.327869 0.209836 0.101639 0 0.360656 0.327869 0.209836 0.101639 02 0 1 5
A majority of wildfires are caused by people and the urban environment, making them the main drivers of wildfire risk.
2018
+
= human causes
0. 0 0 0 0 0
=
percentage of wildfires due to colour coded causes
C a l if o rn ia : A s ta te in f l a m e s
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Apparent vs. Hidden economic costs The graph below illustrates the apparent economic costs of wildfires in the form of insured /
24,000
o v e r a l l l o s s e s 26
Every wildfire comes with its host of economic detriments. The worsening wildfire crisis has led to escalating economic costs in recent years, placing a strain on both residents in wildfire prone communities as well as governmental organisations managing these wildfires. While apparent financial costs are easily quantified, it is also important to recognise the insidious but significant impacts that hidden economic costs have on communities. 26 These are economic impacts that are difficult to quantify, but should be nonetheless be kept in mind in future proofing communities for wildfires. 27
ECONOMIC COSTS OF WILDFIRES I n su r e d Lo sse s
A P PA R E N T ECONOMIC COSTS
HIDDEN ECONOMIC COSTS
15,000
18,000
21,000
O ve r a l l Lo sse s
• Supression
• Public health
• Management
• Tourism Losses
Costs
12,000
Costs
• Emergency
9,000
Funds
• Site
6,000
Rehabilitation
• Fuel Reduction
47
17
18 20
16
15
14
13
12
11
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20
20
20
20
20
20
20
20
10
0
3,000
• Insured Losses
damages
• Water supply & Infrastructural Damages
• Local economic
losses from lost livelihood
Socioeconomic dimension of recovery The demographic of homeowners residing within suburban areas of higher wildfire risks
There are two main categories of Americans living forested suburban areas where wildfires are more rampant: 1. Less affluent communities characterised by retirees and low-income empolyees, and 2. High income affluent individuals seeking for a scenic place to live. The result is an amalgamation of individuals from the two ends of the income scale who will be impacted different and have vastly different responses when recovering from a wildfire.
Median household income in Paradise: 28
$48,831
American Average:
$61,937 Looking back at Camp Fire, the lower to middle income demographic of Paradise places them under a particularly vulnerable group of American homeowners, who are eager to rebuild but lack the financial means to recover in a way that puts them in a better position against wildfires. This form of reconstruction that reverts back to the status quo highlights the nuances that social inequality plays on resilience. Paradise is a reminder of how resilient design should be equitable and accessible for all, especially in the context of an environmental challenge that could subject certain social groups to greater injustices than others.
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3 .2 The Role of wildfires in the Californian
Ecosystem
Wildfires are neccessary for thriving ecosystems Ye t d e t r i m e n t a l t o u r b a n h a b i t a t s ; Can communities continue to live in wildfire prone regions? The photo above shows the wooded hillsides of Fountain Groove flourishing and regenerating after t h e T u b b s F i r e 29
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When urban communities were first confronted with wildfires, deliberate fire supression and even elimination by actively seeking out initial wildfires and immediately extinguishing them became the accepted solution. However, in recent years, the cascading effect of supressing fires over time has instead resulted in larger fires due to the accumulation of ignitable vegetative fuel in fire supressed regions. 30 Wildfires are now understood to be essential to the renewal process of natural forests, and any attempts at tampering with this natural rhythm has been futile at best, and in the case of fire supression, even detrimental to both urban communities and ecosystems alike.
Eliminating wildfires, even if possible, is not ecologically sustainable 1
Overly dense forests start accumulating old, dead or decaying vegetation - wildfires occur as such vegetation become a substantial mass of easily ignitable fuel source, clearing out dead vegetation and releasing trapped nutrients back into the soil. This process rejuvenates forests and ensures their continued sustenance. 31
April - June PRE-WILDFIRE SEASON Ve g e t a t i o n d r i e s up over the summer season
July - September WILDFIRE SEASON
2
Certain species of plants and animals have evolved and adapted to the periodic patterns of wildfires. 32
3
Wildfires can serve as defense mechanisms to weed out invasive species that are not adapted to such fires, and can be detrimental to local indigenous species if their population is left unchecked. 33
Maximum natural fuel content, Strong winds that can carry fire embers over long distance January - March POST-WILDFIRE SEASON Fire returns trapped nutrients into soil: Regeneration & Regrowth of forests
Therefore, in accounting for the role of wildfires in regulating wildland ecosystems, and the impracticality of eliminating wildland fires completely, existing strategies targeted at aggressively suppressing the frequency and impacts of wildfires might not be the most productive for wildfire prone communities. C a l if o rn ia : A s ta te in f l a m e s
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3 .3
Subrubanisation & the American Dream More homes in suburban areas equate to a higher risk of wildfires. Despite the clear ramifications of constructing non-wildfire adapted homes in these regions, the area of developed wildland-urban interface land continues to rise, because socioeconomic incentives of living outside of costly, highly urbanised cities outweigh the fire risks percieved by homeowners. 34 Additionally, the “American Dream”, a term that perpetuates the idea of affording a house with a white picket fence is realised in these lower cost, suburban towns, but at an insidious cost of heightened wildfire risks. Just as much as homeowners can benefit from the carefree life away from the bustling and expensive cities, the losses endured after the event of a fire disaster can leave them stripped of all their property and belongings. Looking at Butte and San Franciso, photos on the following page shows the stark difference in urban development of the two Californian counties. Lower housing costs have been a major pull factor in driving up Butte’s population in recent years: Butte’s 2018 population growth rate stands at 0.89% 35, in comparison to 0.47% of San Francisco. 36 This is indicative of a
Why are more people living in areas of high wildfire risk? An infographic on the differences in housing costs and fire risk of Butte vs. San Franciso
51
Calif ornia: A state i n f l a me s
larger phenomenon of accelerated suburban growth driven by economic factors, which in turn have drastic implications on wildfire risks in these communities. In 2018, Butte experienced a total of 13 wildfires while San Franciso has had none, which is concerning when coupled with the rate at which Butte’s population is growing.
In 2018...
13 fires
occured in
Butte $320,112 median price of a detached home
USD
median price of a detached home
$1,580,300 San 0 Francisco fires USD
occured in
This does not mean that houses in suburia should not be built at all - in approaching wildfire resiliency, urban development should be paired with reccomendations based on risk assessments for each parcel of land, in acknowledgement of the fact that humans have varying preferences on the environment in which they thrive in, and should be able to remain in suburban towns as long as communities are well adapted to accompanying wildfire risks.
BUTTE
SAN FRANCISCO
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3.4 California’s
Housing Crisis More than one quarter of America’s homeless population resides in California, and it is the state with the greatest and fastest growing homeless population. 37 California’s housing crisis is a key driver of the increased suburban developments in high fire risk zones: as housing costs become increasingly unaffordable, people driven out of their homes either relocate to lower cost neighbourhoods or are left homeless on the streets.
Additionally, when wildfires as widespread as the Camp Fire occur, thousands of residents are displaced and become part of the homeless population if inadequate shelters are allocated for the affected homeowners. Therefore, this negative feedback cycle exacerbates the wildfire crisis, and demands for a proposal that considers homelessness as a parallel issue to the wildfire crisis.
The state’s homelessness problem results in two scenarios: either an increase in urban sprawl on suburban land, or an increase in homeless population in conditions that puts themselves and the surrounding community at higher risk of human-caused fires, both of which are detrimental to the wildfire problem.
C A L I F O R N I A’ S P E R C A P I T A LAND CONSUMPTION
Wildlife-Urban Interface
R
C 2.2 R E S S/ O N R
A
E P
P
E
A
C 0.2 R E S S/ O N
All Private Lands
Can future wildfire adapted communities be part of the solution for California’s homeless population? Per capita land consumption is high for houses in high fire risk areas 38, signaling a potential for reduced housing footprint and strategic densification in lower risk areas to accommodate a greater number of more affordable housing units for the homeless.
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3 .5
Existing Approaches towards wildfires
The wildfire policies currently undertaken by California under the conventional resilience model can be split into 6 main categories: fire forcasting, fire management, community response plans, fire fighting protocols, fire rehabilitation and restoration, and wildfire building codes. This chapter assesses some of the successes and limitations of existing measures taken towards wildfire management in California, to answer the question of whether current solutions are adequate in tackling the increasing threat wildfires pose to high risk communities.
1
FIRE FORCASTING
• weather & climate monitoring • fuels & fire danger analysis • fire fighting & fire activity asset intelligience
2
3 4 5
FIRE MANAGEMENT
• fire supression • prescribed burns COMMUNITY RESPONSE PLANS
• evacuation plans • fire fighting infrastructure FIRE FIGHTING PROTOCOLS
• disaster response FIRE REHABILITATION & RESTORATION
• rebuilding public infrastructure • restoring natural land that are unable to recover on their own
6
WILDFIRE BUILDING CODES
• enforcing defensible space around buildings
• use of fire resistant materials
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FIRE SUPRESSION
Fire suppression involves a combination of strategies aimed at directly reducing the occurrence of a wildfire, such as logging to reduce natural fuel loads close to urbanised areas, or aggressively snuffing out fires at the first sight of a flame. 39
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PRESCRIBED BURNS
Also known as controlled burning, prescribed burns involves scheduled fires that are strategically planned and kept contained under close monitoring. Prescribed burns are done with the understanding that wildfires are essential in clearing accumulated vegetation fuel periodically in order to prevent large uncontrollable fires in the future. 40
57
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E VA C U A T I O N P L A N S
Identification of escape routes and key points of egress for residents evacuating in the event of a wildfire ensures an organised response in the event of a wildfire. In the case of Paradise’s Camp Fire, the allocation of two main arterial roads leading out of the town (Skyway Road and Clarke Road) as designated escape routes were credited for helping reduce the loss of lives during the disaster. 41
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FIRE RESISTANT CONSTRUCTION
In 2008, California passed building code 7A which enforces strict construction standards for homes built in high wildfire risk zones. The code lays out a series of requirements from vegetation management to the use of fire resistant materials with the aim of maximising home survival rates in a wildfire. In an experiment conducted by the Institute of Business and Home Safety, homes built to be fire resistant did not burn when exposed to the same embers which ignited its non-fire resistant counterpart. 42
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Calif ornia: A state i n f l a me s
FIRE FIGHTING INFRASTRUCTURE
California has a comprehensive suit of fire fighting infrastructure, coupled with a series of standard operating procedures that determine which of these resources will be deployed in different wildfire scenarios. Examples include fire fighting helicopters, training camps, as well as intra-agency command centers. Further studies on the design requirements and architectural typologies of these fire support infrastructure can be found in Chapter 5.1.
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REBUILDING PUBLIC INFRASTRUCTURE
Many public infrastructure, especially those built years ago are not designed to withstand today’s wildfires. In the case of power lines, that have even become the source of ignition for a significant number of California’s most devastating wildfires. Current approaches to wildfire recovery involves the rebuilding of damaged public infrastructure that are essential to a community’s function, sometimes in a way which reduces its risk of future damage such as relocating power lines underground. 43
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Calif ornia: A state i n f l a me s
The merits of existing approaches based on the existing wildfire resiliency framework were discussed in the earlier pages. However, there are compelling shortcomings that need to be brought to light in the conversation towards improving future wildfire resiliency, which will serve as the basis for the development of a new and updated set of solutions.
Fallacy of Fire-Proof Architecture
Outdated public infrastructure are only improved after being damaged by wildfires
• Less flammable materials do not make
• The destruction of water supply systems
a building fire-proof, it merely makes it fire-resistant
• Elements to a home which makes a
space comfortable and livable such as windows and furniture are readily ignitable, even if the structural components of the house are fireproof (ie. a concrete bunker is completely fireproof but makes for a uncomfortable housing environment)
• While necessary in reducing fire risks, it
and power lines is a main inhibitor to the restoration of a wildfire stricken community
• Key public infrastructure are not
designed to withstand the intensity and frequency of wildfires
• Current measures do not incentivise
the upgrading and redesigning of such services, which results in displaced residents that are unable to move back or recover after a disaster
is not sufficient on its own in enabling homeowners to live safely in wildfire prone communities
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Fire supression strategies are counterproductive
• Fire supression through aggressively
putting out fires causes dried vegetation to accumulate in wildland areas this means that when a fire actually catches, it spreads faster, at a greater magnitude, and inflicts a greater scale of destruction. 44
• Logging forests, in reducing vegetation
fuel, can backfire when the natural wind buffer provided by forests is removed in the process - this can result in faster spreading fires, as in the case of the Camp Fire where the santa diablo winds exacerbated the magnitude of the fire within the urban regions of Paradise. 45
Optimising landuse in wildfire communities
The psychology of disaster response
• Currently, California enforces wildfire
• Homeowners are faced with the choice
• However, wildfire risks undergo seasonal
• The fallacy of fire-proof architecture
building codes and policies targeted at its list of high-risk communities cycles, which mean that the urban footprint can afford to extend further into wildland during low-risk seasons and be vacated during the summer months to maximise land use
• Vacated architecture can potentially
serve as seasonal fire support facilities or structural buffer zones during a wildfire
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Calif ornia: A state i n f l a me s
of evacuating or staying to defend their property in the event of a fire contributes to a false sense of security in choosing to stay and defend
• The attachment to personal belongings
encourages residents to stay put instead of following evacuation protocol
• Planning for evacuation without
consideration for the human reaction in response to a fight-or-flight situation can result in unwanted casualties
Charting the recovery process: rebuilding Santa Rosa after the Tubbs Fire revealed the common flaw of inadequate recovery response plans for communities affected by l a r g e r t h a n n o r m a l f i r e s . 41
Existing wildfire measures do not prepare communities for recovery: from ill designed public infrastructure that takes a long time to rebuild after a wildfire to a lack of a centralised recovery plan for homeowners increases the time and cost of rebuilding and returning to an affected neighbourhood. In achieving a fire adapted community, the deterrence to rebuild after a wildfire should be as much as possible reduced, so as to minimise the fragmentation and displacement of populations in the wake of a wildfire. For Santa Rosa, its recovery from the Tubbs Fire is typical of many American towns. Even after 18 months, only 273 of the 1,800 buildings destroyed were rebuilt, illustrating the long and arduous recuperation process when existing fire resilience strategies fail to account for disaster recovery.
POST-FIRE: 1800 BUILDINGS DESTROYED 3 MONTHS POST-FIRE 6 MONTHS POST-FIRE
An upward struggle towards recovery
9 MONTHS POST-FIRE
c om p l e t e d
12 MONTHS POST-FIRE
un de r c on s t ruc t i on
18 MONTHS POST-FIRE
1 p i xe l = 10 bui l di n gs obt ai n e d p e rm i t t o re bui l d
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Can adaptive resilience do more?
on destr uction- r ecover y cy cles of a w ildf ir e (see Ch apter 2. 2), a nd th us br idges th e gap w h er e conventional models of re silience is lacking.
TEMPORAL ARCHITECTURE: MINIMISING COST OF DESTRUCTION
Designing for the limits of fire-resistant architecture: while buildings should continue to adopt fire resistant elements, they should also be designed with the possibility of destruction in mind. A temporary architecture that caters for rapid reassembly of modular components on a fire-proof structural frame can minimise the cost of destruction, and allow for adaptive redesign around the structural frame based on a feedback loop model.
PERMANENT INFRASTRUCTURE: ELIMINATING ROADBLOCKS TO RECOVERY
Differenting inevitable vs. preventable losses during a wildfire: although living needs of a house makes it unlikely to be fireproof, hardware/public infrastructure can be built to withstand fires. Past wildfires have exposed certain public infrastructures as a weak link to disaster recovery that should be made fire-proof in an adaptive resilience model.
ELIMINATING IRRATIONAL FA C T O R S CONTRIBUTING TO S T AY - A N D - D E F E N D DECISIONS
Design for architecture with adaptive functions in locations identified through a feedback loop can serve as fire support infrastructure during a wildfire. (eg. fireproof storage of key belongings, fire buffer zones)
REPLACING FIRE SUPRESSION WITH PRESCRIBED BURNING
Fire suppression in the recent years have been proven as a counterproductive measure that results in larger and more aggressive wildfires in the long run. On the other hand, the process of prescribed burning aligns with adaptive resilience’s idea of designing alongside wildfires instead of stubbornly resisting it. By allowing forests to burn as its naturally predisposed to do (but in a controlled environment), prescribed burning is one of the few strategies that have proven to be effective in mitigating wildfires.
FINE-GRAINING URBAN PROGRAMMATIC/ LAND USE
65
A dap tive r esilience at its cor e f ocuses on capitalising
Calif ornia: A state i n f l a me s
After each wildfire cycle, reassessment of seasonal changes in fire risk via feedback loop can inform variations in programmatic use with time, and identify new areas of high and low wildfire risks for readapted planning uses.
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“Adaptive resilience to wildfire means recognizing the limited impact of past fuels management, acknowledging the important role of wildfire in maintaining many ecosystems and ecosystem services, and embracing new strategies to help human communities live with fire.� 46
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Call for a new solution The wildfire threat is growing - solutions should be formulated bearing the realities of wildfires as an inevitable normal. Wildfires are neccessary to ecosystems and hence inescapable for communities located near these ecosystems - design for recovery needs to be a significant element in future wildfire resilient approaches. Homes cannot be truly fireproof without compromising on elements of livability and comfort - they should not be rebuilt with the assumption that they are indestructible. The cyclical nature of fire risk is one of the few predictable elements of wildfires - a time-based approach capitalises on this predictability and enables communities to find rhythm in adapting to wildfires.
There is a need for a renewed look at existing approaches toward wildfire resilience. In the remaining chapters in the book, the potential of adaptive resilience in informing improved strategies in planning and architecture will be speculated and substantiated in greater detail.
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Wildlif e-Urban Inte r f a c e s ( W U I ) : U n d e r st a n d i n g t he U rb a n La n d s c a p e
4 WILDLIFE-URBAN INTERFACES (WUI): UNDERSTANDING THE URBAN LANDSCAPE
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4 .1 Understanding the
Wildland-Urban Interface When speaking of communities at risk of catastrophic wildfires, planners look at wildland-urban interface (WUI) areas, which as its name suggests, refers to urban developments that meet or intermingle with wildland fuel. 47 On the other hand, the quantitative definition by the US Federal Register classifies WUIs as areas containing wildland fuel with at least one housing unit per 16 hectares. 48 In California, the WUI population comes up to 11 million citizens, with 4.5 million homes located in these high-risk regions. 49 Understanding urban morphologies and development patterns of WUIs is hence essential to the formulation of an urban solution based on adaptive resilience.
Based on the quantitative definition of WUIs, an urban study was conducted on Paradise (using post Camp Fire data) by drawing 16 hectare sized grids running parallel to the primary thoroughfares of the town. Building counts were determined for each grid, and highlighted areas radiating from the centerpoint of grids denote WUI regions. The size of each highlighted radii is proportionate to the building density of the WUI region/corresponding grid cell.
Identifying WUIs in Paradise post Camp Fire Ve g e t a t i o n d e n s i t y m a p o f Pa r a d i s e WUI area sized to building density
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Wildfire cycles: an oscillation between two states
73
Ve g e t a t i o n d e n s i t y m a p o f Pa r a d i s e WUI area sized to building density
The following maps illustrates the changes in building density in Paradise before and after the Camp Fire.
Wildlif e-Urban Inte r f a c e s ( W U I ) : U n d e r st a n d i n g t he U rb a n La n d s c a p e
Firstly, the information on the areas that have managed to withstand a wildfire as identified above will feed back into the adaptive resilience model and inform planners on subsequent recovery strategies. Secondly, this series of maps illustrates the changes in urban composition within
a wildfire cycle, highlighting the value of approaching wildfire resilience adaptively. Conventional resilience strategies do not account such time-based changes, whereas adaptive resilience provides opportunites for a more targetted solution aligned with relatively predictable seasonal patterns.
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Classifying wildfire risk in WUI regions using geographical data Th e m a p i l l u st r a t e s t h e ri s k as s oc i at e d wi t h e ac h 16 h e c t a r e sq u a r e p l o t wi t hi n Paradi s e , C al i forn i a.
There are three physical factors contributing to wildfire risk in WUI regions: vegetation density, building density, and topography. 50 The following map takes in Paradise’s geographical data as well as the fire history (number of buildings destroyed by the Camp Fire) and evaluates the wildfire risk of each 16-hectare plot. The radius of each circle is proportionate to the degree of wildfire risk of the corresponding 16 hectare area.
BUILDING DENSITY > de n s i t y, > ri s k of hum an c aus e d wi l dfi re s
TOPOGRAPHY s t e e p e r t e rrai n , > rat e of fi re s p re ad, > wi l dfi re ri s k
VEGETATION DENSITY > de n s i t y, > n at ural fue l s , > wi l dfi re ri s k
FIRE HISTORY > Bui l di n gs de s t roye d by re c e n t wi l dfi re , >wi l dfi re ri s k
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Evaluating densification A study aimed at identifying potential densification areas within Paradise was conducted. Two main factors were taken into consideration when identifying densifiable areas, namely: 1. Wildfire risk and 2 . Proximity to existing evacuation bottlenecks. Regions outlined in white indicate a greater potential for densification due to its lower wildfire risk. These plots are also a further distance away from evacuation bottlenecks which ensures that the population increase will not further strain existing points of crowding along the evacuation network.
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4 .2 Wildland-Urban Interface
Typologies WUIs encapsulate a broad range of territories and highlights key areas of concern with regard to the wildfire crisis. The terminology however requires further resolution on the different ways in which WUIs present itself in the urban fabric, and how then to design for them in relation to the city scale. The United States Federal Register (USFR) has broadly categorised WUIs into three main categories, namely: Interface, Intermix, and Occluded Communities. Each community represents a unique condition that provides a framework in which planning for wildfire resiliency can be approached on a regional level.
of inherent landscape conditions, such as fertile, agrarian land resulting in intermix typologies, or undesirable terrain located within an expanse of flat terrain resulting in occluded typologies. Such information in turn reflect potential wildfire behaviour in their respective settings, which would help planners in formulating solutions to wildfire planning on a finer scale.
The USFR definitions for each WUI typology are as follow: 51 Interface Community; Condition where buildings abut wildland fuel with a development density of 3 or more structures per acre Intermix Community; Condition with scattered structures throughout wildland area with a development density ranging from structures close together to 1 per 40 acres Occluded Community; Condition occurs often within a city, where structures abut an island of wildland fuels An urban analysis of 500 by 500 meter land plots reveal commonalities in landuse development and character within each WUI type, as summarised in the following page. This allows for a finer distinction of WUIs beyond spatial patterns, by also taking into consideration the nature of urban development in these settlements. Apart from landuse, the urban morphologies of WUIs in many cases are also indicative 79
Wildlif e-Urban Inte r f a c e s ( W U I ) : U n d e r st a n d i n g t he U rb a n La n d s c a p e
I N T E R FAC E
INTERMIX
OCCLUDED
Ur ba n C o r e C l u s t e rs
R ural Farm l an d
Open Space
G a r d e n A p a r t m e n t Pods
R ural Sp rawl
Par ks
B u si n e ss/ I n d u st r i al Parks
Suburban C am p us
Paradise, CA; 500 by 500 meter square grid plans identifying common urban conditions associated with each WUI category
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S PAT I A L RELATIONSHIP
STRUCTURE & POPULATION DENSITY
FIRE PROTECTION FAC I L I T I E S
I N T E R FAC E
INTERMIX
Clear line of demarcation between residential, business, public structures & wildland fuels
No clear line of demarcation, wildland fuels continuous outside and within urban areas
Clear line of demarcation between structures & wildland fuels
>4 structures per 5000m 2
Ranges from close dense structures to 1 structure per 5000m 2
>4 structures per 5000m 2, occluded area < 4 000 000 m2
High population density >60 per 5000m 2
Population density 12-60 per 5000m 2
High population density >60 per 5000m 2
Shared local municipal services (Schedule A), Accessible fire protection facilities to combat interior/ advancing fires
District based fire protection services (Schedule B), Less accessible fire protection facilities
Shared local municipal services (Schedule A), Accessible fire protection facilities to combat interior fires
Ta b l e o f S u m m a r y ; Characteristics of Interface, Intexmix & O c c l u d e d W U I s 51
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Wildlif e-Urban Inte r f a c e s ( W U I ) : U n d e r st a n d i n g t he U rb a n La n d s c a p e
OCCLUDED
I N T E R FAC E
INTERMIX
OCCLUDED
Ur ba n C o r e C l u s t e rs
R ural Farm l an d
Open Space
G a r d e n A p a r t m e n t Pods
R ural Sp rawl
Par ks
B u si n e ss/ I n d u st r i al Parks
Suburban C am p us
Paradise, CA; 500 by 500 meter square grid plans (satellite view) identifying common urban conditions associated with each WUI category
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The Urban to Rural Transect The exponential growth of WUIs is a problem intrinsically linked to the emergence of the urban sprawl. Both issues are two sides of the same coin; intermix WUIs, the fastest growing WUI type, is necessarily a condition for sprawl, and sprawl a necessary condition for intermix WUIs. However, while urbanists are concerned with fixing sprawl with the humanistic intention of creating compact, liveable, and self-sufficient neighbourhoods, managing WUIs involves strategies aimed at mediating both the sustainability of the natural environment and the liveability of the urban environment. Therefore, an urban proposal for wildfire resiliency cannot be developed independently of urbanist ideals. The rural-to-urban Transect introduced by Andres Duany provides a plausible common framework that addresses the many facets of urbanism. 52 The Transect organises elements of the built and natural environment in a useful order, and is widely used among urban planners as the basis for the open source Smartcode, a form-based guide to good place making. 53 The following chapter explores the integration of planning for wildfire resiliency into Duanyâ&#x20AC;&#x2122;s Transect framework, and how in doing so facilitates a productive conversation between wildfire resilient planning and other areas of urbanism.
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Wildlife-Urban I n t e r f a c e s ( W UI ) : Un d e r st a n d i n g th e U rb a n La n d s c a p e
The Transect comprises of six main zones with varying physical and social features, namely: Natural (T1), Rural (T2), Sub-Urban (T3), General Urban (T4), Urban Center (T5), and Urban Core (T6). There is an additional category, Special Districts, which refer to zones that do not conform to the 6 T-zones. Examples of Special Districts include power plants, airports and big-box power centers which by their inherent function are distinct from the neighbourhood unit demarcated by the six Transect zones. 54 In identifying the gradation from natural to urban conditions, the Transect model acknowledges the interdependence of the two systems by giving a place for nature in urbanism and urbanism in nature. 52 It also acknowledges the differences in human nature by understanding that each environment, be it urban or rural, has its unique appeal to its inhabitants. Instead of attempting to subvert the urban or the natural, the Transect enables wildfire planning to take on an adaptive approach as opposed to past practices which aggressively sought to eradicate either wildland fuels or urban developments in landscape areas. These methods were reductive and had been proven ineffective, further backing the need for a refreshed solution that looks at working strategically around the urbannature habitat instead. Based on the three main WUI conditions (intermix, interface, occluded), there are associations that can be drawn between the different Transect zone and each type of WUI. For instance, occluded WUIs are unique to T6-4, while intermix WUIs by virtue of its definition are found exclusively in T2-3. Such relationships allow for the adoption of the Transect as a guideline for wildfire planning, where adaptations can be made to tailor to the goals of achieving a wildfire resilient community. 55
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T6: U R B A N C O R E
T5: U R B A N C E N T E R
T 4: G E N E R A L U R B A N
• Highest building density & height
• High building density & height
• Medium building density & height
• Greatest variety of building uses, as
• Great variety of building uses -
• Mixed used buildings of primarily
• Largest building footprint, close
• Large building footprint, close setback
• Medium building footprint, variable
well as civic buildings with regional importance setback to wide sidewalks, tree planting in regular intervals
ranging from retail, offices, and apartment housing to wide sidewalks, tree planting in regular intervals
• Typically found in large cities/towns
residential function
setback to wide sidewalks, tree planting in variable intervals
• Can have a wide range of residential building types: single, sideyard, rowhouses etc.
O C C L U D E D / I N T E R FA C E W U I
DEEP BUILDING SETBACK/ D E F E N S I B L E S PA C E GOOD ROAD ACCESSIBILITY LOW AMOUNTS OF NATURAL FUEL LOWEST FIRE RISK
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W il d l if e -U rb a n In te rf a c e s (W U I): U n d e rs ta n d in g th e Ur ban Landscape
T3: S U B-U R B A N
T2: R U R A L
T 1: N A T U R A L
• Low building density & height
• Low building density & height
• Few to no buildings
• Primarily residential buildings,
• Consists of sparse, single dwellings in
• Land may be unsuitable for settlement
• Smaller building footprint, tree
• Smallest building footprint
• Land characteristics similar to a
adjacent to zones of mixed used buildings
a random arrangement
planting in irregular intervals
• Irregular roads to accomodate for
wilderness condition
• Primarily vegetation - woodland,
natural conditions
agricultural lands, grasslands and irrigable deserts
INTERMIX WUI
LITTLE/NO BUILDING SETBACK/ D E F E N S I B L E S PA C E POOR ROAD ACCESSIBILITY HIGH AMOUNTS OF NATURAL FUEL HIGHEST FIRE RISK
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due to topography, hydrology or vegetation
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T 5: U R B A N C E N T E R
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T 4: G E N E R A L URBAN
Wildlif e-Urban Inte r f a c e s ( W U I ) : U n d e r st a n d i n g t he U rb a n La n d s c a p e
T 3: S U B - U R B A N
T 2: R U R A L
T1: N AT U R A L
Paradise, CA; Rural-to Urban Transact 1:7500 Plan & Section
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4 .4 The dichotomy of
Urban Strategies in planning for WUIs 3
B uildings r ebuilt as per pr e- f ir e locations & specif ications
1
E x t e n si ve bu f f e r z o n e s , min i m a l n a t u r a l
2
4
Foc us e d on wi l dfi re
w il d l a n d s w i t h i n u r ba n
& wi l dfi re -re s i s t an t
a re a s
c on s t ruc t i on
Recover y f ocused on damage contr ol r ath er
s up p re s s i on s t rat e gi e s
th an r ebuilding f or f u tu r e r esilience
CONVENTIONAL RESILIENCE
a hyper-defensive model
3 1
G iv i n g a l l o w a n c e s fo r n a t u r a l su bu r ba n ch a r a c t e r o f W UI co m m u n i t i e s
2
Adaptive ar ch itectu r e: scalable, conver tible,
Foc us e d on de s i gn i n g
r econf igu r able bu ildings th at
for wi l dfi re m an age m e n t
can accommodate ch anging
s t rat e gi e s & s t rat e gi c al l y
pr ogr ammatic u ses w ith
v ul n e rabl e c on s t ruc t i on
seasonal w ildf ir e r isks
ADAPTIVE RESILIENCE
a strategically vulnerable model
4
Recover y f ocused on r apid r eassembly & r ebu ilding f or f utur e r esilience
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Wildlif e-Urban Inte r f a c e s ( W U I ) : U n d e r st a n d i n g t he U rb a n La n d s c a p e
In understanding the urban morphologies of WUI communities as well as ideas on wildfire resiliency, two contrasting scenarios can be extracted from the spectrum of potential urban strategies. While a hyper-defensive model reduces risks for human caused wildfires, it does not eliminate wildfires altogether. The model also dismisses the less tangible, social benefits and dependencies that residents of WUIs derive from living in close proximity to nature. As mentioned in chapter 3, wildfires are essential in regulating wildland ecosystems, and people value WUIs for its suburban qualities. Therefore, rather than taking this quality away by further urbanising WUI regions, a holistic solution is one that works at adapting rather than rejecting the realities of wildfires.
This thesis argues for an adaptable, strategically vulnerable model fitted with the capacity to flexibly react to the volatile nature of wildfire-prone communities, while incurring minimal trade-offs.
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