planning and development of urban settlements in respect of spontaneous growth
TRANSCRIPT
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IN RESPECT OF SPONTANEOUS
GROWTH
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THE NEED
By 2030, an estimated 70percent of Indias jobs willbe in cities, and about590 million Indians will
live in urban areas. Indiasslum population isprojected to rise to 93million this year, or 7.75percent of the totalpopulation, according to areport by the Ministry ofHousing and UrbanPoverty Alleviation.
Thus a need emerges forplanning and directingthe spontaneous growthwhich is to be more
spontaneous than thegrowth itself.
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Why do cities grow?
Urban populations grow in two ways
Natural increase (more births than deaths)It is fueled by improved food supplies, better sanitation
and good medical care. in Latin America and east Asia naturalincrease is responsible for two-third of urban population growth.
ImmigrationImmigration can be caused both by push factors (that force
people out of the area) and by pull factors (that draw them into thecities) .in Africa and west Asia immigration is the largest source ofurban population.
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Urban challenges in the developing world
90% of the human population growth in the next century isexpected to occur in the developing world. Almost all the
growth will occur in cities, which already have trouble
supplying food, water, housing, jobs, and basic services for
their residents. the unplanned and uncontrollable growth of
those cities causes tragic urban environmental problems.
It is estimated that the
slum population will
increase from 32 percentof the worlds total urban
population in 2001 to
about 41 per cent in 2030.
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Traffic congestion
Due to the rapid populationincrease, the traffic problemalso increased. the road aretoo narrow for increasingtraffic which result in traffic
congestion in thesecountries. e.g. in Bangkok anaverage resident spends theequivalent of 44 days a yearsitting in traffic jams. About
20% of all fuel is consumedby vehicles standing still.hours of work lost each yearare worth of least $3 billion
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Air pollutionThe traffic much of it involving old poorly
maintained vehicles, combine with Smokey factories andthe use of wood or coal fires for cooking and heatingcontribute to air pollution. An estimated 60% ofCalcutta's residents are thought to suffer fromrespiratory diseases linked to air pollution.
Water pollutionThe disposal of solid waste into water bodies and
insufficient sewage treatment causes water pollution in
developing countries. e.g. in Latin America where only2% of urban sewage receives any treatment. some 400million people in developing world cities do not have safedrinking water.
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Urban sprawlCities that once were compactnow spread over the landscapeconsuming open spaces andwasting resources. This patternof urban growth is known assprawl. This is the urban
challenge in the developedworld. Sprawl eat up openspaces, it consume thousand ofacres of forest and farmland,woodland and wetland because
these sprawl cities often arelocated in fertile river valleys orshorelines, much of that landwould be especially valuable forproducing crops for local
consumption.
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Characteristics of urban sprawl
Unlimited outward extension.
Low-density residential and commercial development.
Leapfrog development that consume farmland and natural
area. Fragmentation of power among many small units of
government..
Dominance of freeways and private automobiles.
No centralized planning or control of land use.
Widespread strips malls and big-box shopping centers.
Decaying city centers as new development occurs inpreviously rural areas.
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CITYS GROWTH
Agglomerations of individually initiated buildingsalong natural paths of movement
The most intensely used natural paths ofmovement acquire an importance
These paths eventually form the familiarorganic pattern of streets seen in medievalcities.
This process still takes place today in areas wheregovernment is weak or dysfunctional and in theinfamous squatter slums that have proliferated inthe 20th century.
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SPONTANEOUS ORDER THEORY
Given by Friedrich A. von Hayek (Hayek, 1973)
Spontaneous order is the spontaneous emergence of order out of
seeming chaos; the emergence of various kinds of social order from a
combination of self-interested individuals who are not intentionally trying
to create order through planning.
Examples:
The evolution of life on Earth
Language
Free market economy
Anarchism
Naturalists often point to the inherent "watch-like" precision of
uncultivated ecosystems and to the universe itself as ultimate examples of
this phenomenon.
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PLANNING
Planning has to be done for both the existingland-uses to blend with the upcoming growthpatterns.
To predict the future expansion or growth. GROWTH FORCASTING
Sleuth model
Cellular automaton Smart growth
Land-Use and Land-Cover Change - LUCC
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SLEUTH MODEL
Slope from Digital Elevation Model in %
Land cover
Exclusion -- Areas resistant to urbanization. Water bodies, parks, wetland,protected game land, floodplain, etc.
Urbanization
Transportation -- Simulate the influence of roads on development.Assign different values based on road accessibility.
Hillshade -- Used as background to identify the spatial extent
Appropriate Coefficients used for prediction
Used for: New York, Detroit, Chicago, Washington D.C., San Francisco,and Albuquerque, Netherlands, Portugal, South America, Africa,and Australia
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CELLULAR AUTOMATON
Each cell in a row is an actor,making a decision on its nextaction based on its state and thestates of its direct neighbors (itscontext). All cells share the samerule set to determine how to do
this, that is to say all cells will actthe same way with the samecontext. In this way each row isthe product of the actions of thecells in a previous row, forming afeedback loop. The patterns ofthese rows are not in themselvesinteresting, but when collected ina sequence and displayed as atwo-dimensional matrix, theydevelop complex structures inthis dimension.
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Smart Growth
Smart growth is a term that describes such strategies for well planeddevelopments that make efficient and effective use of land resources andexisting infrastructure.
Goals for smart growth
Create a positive self-image for the community. Make the city vital and livable.
Solve problems with air, water, toxic waste, and noise pollution.
Improve communication between groups.
Alleviate substandard housing.
Concentrates growth in compact walkable urban centers to avoid sprawl
'urban intensification
Influenced Government planning policies in the UK, the Netherlands andseveral other European countries.
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Land-Use and Land-Cover Change -
LUCC
Addresses the question: How do human andbiophysical forces affect land use and hence land cover,and what are the environmental and social impacts ofthis change?
The pace, magnitude and spatial reach of humanalterations of the Earth's land surface areunprecedented. LUCC research addresses the problemof land use dynamics through comparative case studyanalysis, addresses land cover dynamics through
empirical observations and diagnostic models, andextends the understanding of cause-use-coverdynamics through integrated regional and globalmodelling.
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Curbing Excess Sprawl with
Congestion Tolls and Urban Boundaries
The part of sprawl that is caused by distortions may be called excesssprawland its reduction or elimination is a reasonable policy goal if thiscan be done without creating other more harmful distortions.
The automobile-related distortion causing the excessive sprawling of landuse is un priced traffic congestion.
Economists have known for decades that the lack of marginal cost pricingin urban transportation makes road travel cheap and that the misuse ofcost benefit rules by transportation planners has resulted in too muchhighway-building, causing too much urban expansion into suburban areaswhere land was initially cheap.
One of these is the policy of levying optimal congestion tolls on traffic,favored by economists.
The second is a planned urban boundary (also known as an urban growthboundary or UGB) that reduces the urban radius and beyond which thereis a greenbelt in which urban development is not allowed or is severelylimited. A good example is the UGB around Portland, Oregon.
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Using such a model suitable for modern cities, we establish several results.
First, we show that as employment and residences decentralizeout of the center, commutes are shortened because average distancesbetween jobs and residences are reduced.
Second, road planners in our model can finance roads by levying a headtax or by implementing first best congestion tolls.
When tolls are used, roads become self-financing and the initial aggregateover allocation of land to roads is self correcting in the long run with lessroads being allocated to the suburbs and more to the heavily congestedcenters.
We show that the excess sprawl induced by un priced congestion andinitially misallocated roads result in a daily average travel time ofcommuting plus discretionary round trips per worker that is about 8minutes or 13% too long. The congestion tolls eliminate this excess travelor excess sprawl by making the job and residence distribution of the citymore compact. In doing so, efficiency gains of about 0.22 % of averageincomes are achieved.