helena farrall - faculdade de ciências e tecnologia / unl

Coberturas Verdes Benefícios e Oportunidades de

Intervenção na Cidade

Helena Farrall

Helena Farrall Workshop COBERTURAS MEDITERRÂNICAS VERDES E PRODUTIVAS, 24Feb2011

Coberturas Verdes: Benefícios e Oportunidades de Intervenção na Cidade

URBAN AREAS – Cities & Population Dynamics

Source: Duh et al., 2008

Location of the 100 bigest cities in 2005 3.1 Million inhabitants - 35.2 Million inhabitants

20 Megacities ( > 10 Million inhabitants )



THE URBAN WATER CYCLE




Soil sealing

Before Urban Development




Soil sealing

After Urban Development




Soil sealing

Source: EEA, 2010 UMZ - Urban Morphological Zones




Soil sealing in Lisbon

UMZ - Urban Morphological Zones Source: Farrall & Joaquim, 2011 (on data from EEA, 2010)




IMPACTS OF UNMANAGED STORMWATER

• Inundations in urban areas

property damages

• Changes in watershed hydrology

• Changes in infiltration to ground water

• Changes in stream hydrology

morphology

• Changes in riparian zone habitat

• Changes in water quality

• Changes in aquatic habitat / ecosystem




UMZ - Urban Morphological Zones



THE URBAN WATER CYCLE - WHY TALK ABOUT RESILIENCE Natural catastrophes – a portrait of the last 50 years

Source: MunichRe, 2002



Source: MunichRe, 2002

THE URBAN WATER CYCLE - WHY TALK ABOUT RESILIENCE Natural catastrophes – resulting economical losses



THE HEAT ISLAND EFFECT - WHY TALK ABOUT RESILIENCE

Stored heat flux (QG) of Lisbon (From: LOPES, 2003)



THE HEAT ISLAND EFFECT - WHY TALK ABOUT RESILIENCE

Available energy (QG/Q*), surface temperature (Ts) and albedo – Liisbon W/E (From: LOPES, 2003)



WHY TALK ABOUT RESILIENCE - COMPLEX SYSTEMS

Source: Rouse, 2007

System with a high number of elements, dynamically and mutually interacting. CHARACTERISTICS

• Open systems • Boundaries difficult to establish • Have memory • Integrates different scales (time, space) in a nested way • Non linear relationships

integrating + and/or - “feedback loops” • Integrates dynamic relational networks

multiplicity of hubs and connections • produce emergent phenomena



WHY TALK ABOUT RESILIENCE - COMPLEX SYSTEMS The City - Elements e Processes

Fonte: Rouse., 2007



WHY TALK ABOUT RESILIENCE - COMPLEX SYSTEMS The Tipping Point Effect

Fonte: Scheffer, 2010



Fonte: Dyer 2001 in Real, 2009

WHY TALK ABOUT RESILIENCE - COMPLEX SYSTEMS Chain of Events



2 DIFFERENT PERSPECTIVES • Rate and speed of return to pre-existing conditions after perturbation. • Magnitude of disturbance that can be absorbed before the system changes its structure by changing the variables and processes that control the system’s behavior.

THE CONCEPT OF RESILIENCE



THE CONCEPT OF RESILIENT SYSTEM

Source: Folke et al., 2002

A SYSTEM that has

• the capacity to absorb the consequences of a disrupting event

• The capacity to reorganize during the transition period

so as to keep its functions, structure and feedback relations, i.e. its identity




Fonte: Godschalk., 2003

8 ASPECTS OF A RESILIENT SYSTEM (1-4)

REDUNDANT

with a number of functionally similar components so that the entire system does not fail when one component fails;

DIVERSIFIED

with a number of functionally different components in order to protect the system against various threats;

EFICIENT

with a positive ratio of energy supplied to energy delivered by a dynamic system;

AUTONOMOUS

with the capability to operate independently of outside control.;




Source: Godschalk., 2003

8 ASPECTS OF A RESILIENT SYSTEM (5-8)

RESISTANT

with the power to resist attack or other outside force.

INTERDEPENDENT

with system components connected so that they support each other;

ADAPTABLE

with the capacity to learn from experience and the flexibility to change;

COLLABORATIVE

with multiple opportunities and incentives for broad stakeholder participation.




Qualities of people, communities, agencies and infrastructure that reduce vulnerability through the capacity to

[1] prevent, mitigate losses and then, if damage occurs, [2] to mantain normal living conditions and to [3] manage recovery from the impact.

Source:Buckle, Marsh and Smale (2000)



RESILIENCE : RECOVERING AFTER A (MAJOR) EVENT

REGENERATION OF A CITY 4 Processes

1. Emergency Response

2. Restoration

3. Reconstruction

4. Development / Growth

Source: Haasetal, 1977



RESILIENCE : RECOVERING AFTER A MAJOR EVENT (S.Francisco, 1906)

Fonte: Vale & Campanela, 2005



RESILIENCE : RECOVERING AFTER A MAJOR EVENT

Source: Vale & Campanela, 2005

LOGARITMIC SCALE 1. Emergency response(TRE)

2. Restoration (TRES)

3. Reconstruction (TREC)

4. Development (TDES)

Time Period

1. TRE

2. 10 x TRE

3. 10 x TRES

4. TDES



EVOLUTION OF STORMWATER MANAGEMENT (in 3 slides)

1. Drainage

• Problem - too much water • Solution - flood control through managing / treating storm water in large end-of-pipe facilities located often at the bottom of drainage areas



EVOLUTION OF STORMWATER MANAGEMENT (in 3 lides)

2. Natural Water Cycle Emulation

• Problem - too much, too poor water quality

• Solution - manage rainfall by using design

techniques that infiltrate, filter, store,

evaporate, and detain runoff close to its source



EVOLUTION OF STORMWATER MANAGEMENT (in 3 slides)

2. Natural Water Cycle Emulation

Replicates virtually all components of the natural water cycle by:

• Minimizing total runoff volume

• Controlling peak rate of runoff

• Maximizing infiltration and groundwater recharge

• Maintaining stream baseflow,

• Maximizing evapotranspiration, and

• Protecting water quality

RESILIENT SYSTEM

1. Redundant

2. Diverse

3. Efficient

4. Autonomous

5. Resistant

6. Interdependent

7. Adaptive

8. Collaborative



NATURAL WATER CYCLE EMULATION

DECENTRALISED STORMWATER MANAGEMENT

1. Green Roofs

2. Impervious Runoff Dispersion

3. Rain Gardens / Bioretention

4. Permeable Pavements

RESILIENT SYSTEM

1. Redundant

2. Diverse

3. Efficient

4. Autonomous

5. Resistant

6. Interdependent

7. Adaptive

8. Collaborative



GREEN ROOFS – MAIN ADVANTAGES (in a nutshell)

1. Increased thermal insulation

2. Increased roof lifespan

3. Storm water attenuation

4. Evaporative cooling

5. Reduced heat island effect

6. Support for biodiversity

7. Synergies with PV, solar heat

8. Amenity areas / use of space

9. Noise / air pollution reduction

OBRIGADA

Coberturas Verdes Benefícios e Oportunidades de

Intervenção na Cidade

helena farrall - faculdade de ciências e tecnologia / unl

Technology