Urban Risks

Taranjot K GadhokChief Projects , Hudco

The Urbanizing World • By the year 2025, half the world’s population will reside in

Urban areas and 90% of this would be in developing nations

• Most troubling manifestation of this transformation is the growth of mega-cities.

• There would be 100 mega cities(pop>10million) in the world.

• India’s major concern is mere numbers

• Growth of Urban population is twice the rate of its total population.Major growth in 1 million cities which have increased from 23 in1991 and to around 35 by 2001

Increasing Mega cities

An Era of mega-cities …..

In 1950 ten of the 15 most populous cities were in industrial countries.by 2015 there will be only three mega-cities in industrial countries among the top 15

Cities –

a Cause of Risks? or are at Risks??

A cause - Deforestation??Urbanization has caused man’s manifestation of nature.Cities cause:

• Discernable human influence on global climate

• Deforestation wrecking ecological defenses against• catastrophic natural events, like winds, torrential rains and heat of the sun.

• Destruction of upland forests on the other hand reduces the ability to absorb rainwater. A single tree can absorb 200 liters of water or more per hour.

• Both loss of the binding of soil by the roots and holding of impact of the rain by the canopies cause instability on the hill slopes causing landslides.

• The loose soil that runs into the rivers causes silting of the river beds again causing floods apart from loss of the most fertile top soil.

• Landslide at Malpa killed more than 300 people within a week.

A cause – climate change

Although coastal regions form only a small part of planet, but hosts almost 3 billion people almost half the world’s population.

As green house gases warm the earth’s surface sea temperatures rise. Causing world’s oceans to expand and occupy more space.

Global warming making the forces of wind, rain and sun harsher to predict and counter.

Small island states are perhaps the most vulnerable to rising sea levels.

With 44-cms rise in sea levels predicted by 2080 flooding would increase ten fold.

Individual cities at risk would include Tokyo and Shanghai, respectively of the largest and fifth largest cities of the world.

Biggest threats are to the river deltas.Present estimated cost of protecting shore lines in ,Maldives is already US $ 13,000 per meter.

Cities responsible for climate change causing disasters

Trends and losses

The chart shows the number of great natural catastrophes for each year, divided according to type of event.

The trend curves confirm an increase in catastrophe losses since 1950

In the Past two decades alone economic costs due to natural disasters has multiplied five fold $629 bn

Source : Topics 2006 Munich Re

Scenario

Asia suffers largest number of disasters

Maximum economic losses are due to floods while maximum fatalities are due to wind storm events

The ScenarioNumber of people affected by disasters has been growing @ 6% annually.

3 million people have lost their lives in natural disasters since 1960.

In 1988-above 50,000 lives and economic losses worth over 90 billion US dollars (Rs380,000 crores) were claimed by disasters.

Asia is identified as being the most disaster prone area with India and Bangladesh being major disaster prone nations.

• Real annual economic losses averaged

- $ 4.9 billion in 1960’s

- $ 9.5 billion in 70’s and

- US $ 15.1 billion in 1980’s which increased to

-US $ 75.9 billion in 1998 (real prices).

-Record losses of $191 billion were experienced in 1995 the year of Kobe earthquake

These costs are based on direct physical losses of fixed capital and inventory and does not contain socio-economic costs like, injuries health and death of communities affected or long term consequences and fiscal imbalances

Losses

Changing face of losses Across countries

Nature of impacts alters from developed to developing economies Hurricane

Hurricane Andrew struck Florida in 1992- Damage was $22bn- 0.3 % of GDP and 14 fatalities

Typhoon Angela cost only 0.1%of GDP in Philippines but caused 916 fatalities

Incase of Hurricane Mitch in Honduras losses equivalent to 41% of GDP were assessed.

A pattern of losses

Pattern of Losses

General lessons to be learnt

Developed nation suffer more economic losses due to higher cost of infrastructure and assets while developing nation suffer losses in terms of increased number of deaths and social and environmental damage

Little or no financial instruments exist in many developing countries to support,prevent or prepare for such eventualities except for mechanisms for relief and rehabilitation

Cities are more prone to impacts as they host larger population densities and higher cost and dependence on infrastructure, high-rise buildings and larger built environment

Poor, women, children and the aged are more vulnerable to impacts of disasters as they have lower capacity to cope with emergencies

Very little has been achieved in taking pro-active measures and preparedness.

Why cities are at larger risk?

Cities are generally characterized by extreme concentrations of people, values and infrastructure. Yet one city is not necessarily the same as any other.

The risks and impact of any catastrophe would be much larger in urban areas because

The value of damage and effort of rehabilitation would cost much more.

Also global urbanization is occurring fastest in most vulnerable parts of the world.It is the pacific rim referred to by geologists as ‘ring of fire ‘because of its propensity to

earthquakes and volcanoes.

It has been established that 40 out 50 fastest growing cities are in earthquake zone.

Half the populations of cities are in living in squatter settlements, due to their poor access to basic resources are most vulnerable to disasters.

High concentration…larger impacts

The high concentration of people, values and infrastructure in a confined area.

Thus when Typhoon Nari passed overTaipei in September 2001 with relatively insured damage of around US$ 500m. Heavy rains left the city’s underground railway stations flooded after the pumping system failed, paralysing its most important traffic artery for weeks on end.

Infrastructure networks and the interdependence of different urban functions and of the various districts increase the risks dramatically.

Migration from the land and migration, especially in poor countries pushes people into highly exposed peripheral area (fluvial plains, sloping sites, etc.) and live in makeshift structures that offer no protection at all.

The constant expansion and restructuring of cities means a patchwork of buildings of different sizes, age and unplanned growth not guaranteed basic services.

This gives rise to problems with coordinating aid from home and abroad. The severe earthquakes in Turkey in 1999 are prime examples of this.

Risks due to GlobalizationUrbanization without adequate control of local authorities leads to unplanned growth.

It is the capital flows that govern the demands on goods and services which can be catered to by private sector only.

Local needs get ignored and supply reduced.

Multinationals come to cities with their own agenda looking at the returns and exploiting the cheap labor,ignoring the local environment laws. Leads to speculation of the prices of the urban environmental services.

Poor can ill afford these services often occupying illegal and informal, vulnerable places for survival in cities.

Master plans do not cater to these informal populations which are a necessary need at the same time a risk interns of carriers of disease, corruption and crime.But they have silent consent of the local govts. who are incapable to provide alternative solutions.

Risks due to Built Environment??

Here, torrential rainfall can soon lead to local flooding, and even to devastating flash floods and landslides, which then affect mostly the poorer social strata.

High-rise buildings, towers, masts and antennas regularly attract lightning. In storms, the towering buildings of many mega-cities act like magnets for lightning.

Concrete buildings and paved areas heat up considerably when they are in the sun. This effect is particularly serious when there are long heat waves, because it considerably reduces night-time cooling.

The “heat islands” that are clearly recognizable in satellite pictures impact convection and so have an effect on the wind system in the surrounding area.

Risks due to Pollution

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Cities influence the climate on a global scale, for around 80% of the greenhouse gases that affect the climate are emitted in cities, even though these cover only 0.4% of the earth’s surface.

High concentrations of aerosols, exhaust gases and dust are emitted in cities. they contain the condensation nuclei for the formation of haze, fog and clouds, and so affect the radiation climate in conurbations

Summer smog, which forms when there is a combination of strong sunshine and high levels of nitrogen oxide emissions from traffic, places considerable strain on health in the big- city environment.

In the winter months, inversion weather situations arise more frequently in cities than in the surrounding countryside, with air quality deteriorating significantly as exhaust gases and other pollutants are trapped in a layer close to the ground.

The biggest civil industrial accident ever – the escape of methylisocyanate (MIC) from a Union Carbide plant in Bhopal on 3 December 1984 – was unique in many respects. The number of victims is estimated at between 12,000 and 20,000 dead and 200,000 injured

Crowding -Health Risks

Having lots of people living together in a crowded area makes city dwellers susceptible to infectious diseases. Air pollution, poor nutrition and lack of medical treatment means that many people’s health is already seriously impaired.

Increased consumption and production of waste causes human dealing with larger refuse and the associated threat to public health is its collection and removal. Case of Surat that suffered Plague.

In recent years, mega-cities have seen the spread of yellow fever, malaria and dengue – diseases that were previously mainly endemic to the countryside. Mosquitoes, which transmit the pathogens, find breeding grounds in cities too

Each year, around three million people worldwide die from tuberculosis. A person suffering from tuberculosis in the poorest neighborhoods infects an average of ten to 15 people each year.

Indian Scenario

Although largely a rural country it has almost 300 million urban dwellersA coastline of about 8000kmsReceives a precipitation of 400mhmeters

75% of this rainfall is received only during four months of monsoons, causing blockage of drainage systems and flash floods in cities.

Indian ScenarioIn fact, the Indian sub-continent is amongst the world’s most disaster prone areas with:55% of land vulnerable to earthquakes and landslides8% of the country vulnerable to cyclones5% of the country vulnerable to floods The Himalayan belt constitutes one of the most seismically active regions in the world. Four earthquakes of magnitude of 8 plus have occurred in this very belt in last 100 years

Large Indian Earthquakes

About 610 million people reside in the area of highest seismic risk in the north, where there have been seven large- magnitude earthquakes during the last 100 years.

EMERGING ISSUESEmerging Issues

• .Urban areas are more at risk.

l In the urban situation there is very thin line between manmade & natural disasters.

l It is not hazards/events that kill, it is the buildings & the built environment that kills & damages the most.

l It is the weak and poor who are most vulnerable.

l It is the communities & Human Settlements which need to be prepared to react to such events because they are the first to be affected.

•

What is Risk?

• Chance or Probability of Encountering Injury or Loss Due to A Specific Phenomenon or A Hazard.

RISK = Hazard X Vulnerability Capacity to Manage It

RISK

• Hazard Identification and Prevention

• Hazard intensity can be reduced by moving people away from hazard locations or protecting them.

Reduction of Vulnerability Bya) Preparing Shelters & Infrastructure.b) Preparing People.

•Cost benefit would quantify better option.

STEPS IN RISK ASSESMENT

A. EarthquakesCan cause ground failure along the fault zone giving rise to landslides,differential settlement ,soil liquefaction

B. CyclonesHorizontal forces that can cause - sway,overturning or collapse of tall structures, suction within buildings causing negative pressure,lateral horizontal deflections at supports,

C. Floods Can cause-sudden horizontal pressures at plinth level can shear off the superstructure,can waterlog and sink foundations, differential settlement along the fault zone giving rise to landslides,differential settlement ,soil liquefaction

RISK MANAGEMENT IN HUMAN SETTLEMENTS

Mitigation plans to form a part of any development plan and a physical plan.

•Greater emphasis should be laid on using GIS as a tool for hazard mapping

•Vulnerabilty atlas in place, can be used as a baseline for identifying technologies and district wise action plans for retrofitting and repairing units which are most vulnerable.

•Inventory of chemical storages and recycling units to be prepared specifically for squatter settlements.

•Involving students from architecture and town planning departments for preparing hazard maps

RECCOMENDATIONS

Thank You

Taranjot K GadhokChief Projects, HUDCO