density and urban form

7/29/2019 Density and Urban Form

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READING

UD / 2012 / SPA

MRIGANK MAYANK THE

DENSITY AND URBAN FORM


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READING Urban Form (morphology)

Study of the form of human settlements and the process of their formation and

transformation.

Understanding of spatial structure and character of ametropolitan area, city, town or village by examining thepatterns of its component parts and the process of itsdevelopment.

Analysis of physical structures at different scales aswell as patterns of movement, land use, ownership orcontrol and occupation.

The study of urban tissue, or fabric, as a means ofdiscerning the underlying structure of the built landscape.


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Tools and theories for urban form

The tools for analyzing Urban Morphology have some theories like: Space syntax,

Figure and Ground etc. Three Theories of Urban Spatial Design:

1. Figure and Ground2. Linkage theory

3. Place Theory

URBAN

FORM

DENSITY

INFRASTR-UCTURE

LANDUSETRANSPORT

LAYOUT


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Concept of Density

The concept of density in urbanism is frequently used to describe the

relationship between a given area and the number of certain entities in thatarea. These entities might be people, dwellings, services, or floor space.

It is a formula for managing city growth. However, it is possible to suppose that

this is a quite reductionist way of approaching the issue of density, since it is a

broad and complex concept.

DENSITY

DESCRIPTIVEPRESCRIPTIVE

Urban density used to describe a

built environment.

Urban density used as a norm in

the process of planning and

designing the city.


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Concept of Density

DECEPTIVELY COMPLEX CONCEPT WITH A NUMBER OF INTER-

RELATED DIMENSIONS.

OBJECTIVE

SPATIALLY BASED

NUMBER OF PEOPLE IN AGIVEN AREA

EXAMPLE CANNAUGHT PLACE, WHILE THEREPORTED DENSITY MAY BE LOW, THE PERCIEVEDDENSITY AND EXTENT OF CROWDING MAY BE VERYHIGH

SUBJECTIVE

SOCIAL INTERPRETATION

INDIVIDUAL DEPENDENT

COMPLEXITIES OF DENSITY1. Difficult to measure

2. The logic of density and its implications for urban form in different scales of

analysis

3. Conditions subjective and qualitative


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CULTURAL DIMENSION

People live is considered as relative. Example, Current English housing policy

states that new residential building should be at a minimum of 30 dwellings/ha

which for some may be an unacceptably high density (DCLG, 2006). In Hong

Kong however, a minimum of ten times that density would be considered low.


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Density as a measurement

Residential density

number of people (population density) or the amount of housing (accommodationdensity) in a specified area of land.

Five Density measures

FAR Floor area / Site area

GC Building footprint / Site areaSOS Open space area / Site area

OSR Open space area / Floor area

SCR Open space area X Floor area / Site area2 = SOS X FAR

FAR - Urban morphology

People/Hectare - Regional planners and geographers

The measurement methods are:

1. Population and dwelling density

2. Land use intensity

3. Coverage

4. Building height5. S aciousness


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Illustration of city form

Factors included

FAR

GCOS

OSR

SCR

SAME DENSITY IN DIFFERETN LAYOUTS WITH VARYING GC AND CONSTANT FAR


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IDENTICAL FAR OF 1 AND GC .2

IDENTICAL FAR OF 1 AND GC .4


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RESIDENTIAL DENSITY OF FOUR DIFFERENT URBAN FORMS


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Population Density & Morphology

DELHI (PEAK DEN. 96460)

(IINNER AREA 19636)

(ADMINISTRATIVE AREA 9340)

MUMBAI (PEAK DEN. 101066)

(INNER AREA 34348)

(ADMINISTRATIVE AREA27378)

KOLKATA (PEAK DEN. 78355)

(INNER AREA 20483)


BANGALORE (PEAK DEN. 75169)

(INNER AREA 18225)


(Source - Urban Age)Density (person/km2)


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Density is largely driven

by topographical

constraints and thelocation of public

transport and other

infrastructure, but also

by each citys inherited

traditions of urban

planning anddevelopment.

While high density is sometimes associated exclusively with poorand overcrowded urban environments, it can also enable a higher

quality of life and reduce the environmental impact of cities by

facilitating walking and cycling. In doing so, high density urban

areas can enhance a citys vitality and make the provision of

public transport and other amenities more viable.

Sky

lineofMumbai


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Skyline of Delhi Skyline of Kolkata

Density is largely driven bytopographical constraints

Density is not necessarily indicative of a particular morphology

Urban Planning and developmentrule define the skyline


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Skyline of BangaloreUrban Planning and development rules

define the skyline


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Population Density representation

Bandra Kurla, Mumbai

Pudong, Shanghai

Downtown Manhattan


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Population growth trend

In the 1990s, Indias population grew by a dramatic 23%, but this fast growth was

outpaced in the main cities. In Delhi the number of residents jumped by 70%,

although this was partly due to a boundary change and Bangalore grew by 38%.Mumbais population grew by 21%, falling back slightly on its relative position.

In contrast Kolkatas population was almost flat, at least by Indian standards, at

4% growth. Projections suggest population growth nationwide will continue but at

a reduced rate of 14% to 2010, with growth in Bangalore pull ahead of that in

Delhi and other cities.1950 2007 2020

Mumbai 2,857,000 18,963,000 23,931,000

Delhi 1,369,369 16,671,894 23,705,710

Kolkata 4,513,496 14,827,582 18,799,710

Bangalore 745,999 6,963,832 9,531,009

New York 12,338,471 19,040,493 20,369,956

Shanghai 6,066,000 14,986,000 18,464,000

London 8,361,000 8,567,000 8,618,000

Mexico city 2,883,000 19,957,000 22,185,000

Johannesburg 900,000 3,420,000 3,741,000

Berlin 3,351,757 3,405,954 3,435,579


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Density Major cities

(Source - Urban Age)


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Density Major cities



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Density patterns

VERY HIGH DENSITIES IN THE

CENTRES OF MUMBAI AND SHANGHAI

LOWER DENSITY DEVELOPMENT

PATTERNS OF BERLIN ANDLONDON

LIMITED AREAS OF HIGH DENSITY

AROUND A DOWNTOWN IN

JOHANNESBURG IN THE MIDST OF A

VERY LOW-DENSITY SPRAWL

IN NEW YORK, CONSTRAINTS OF

WATERWAYS DRIVE DENSITIES

THAT RISE TO A SPIKE IN

MANHATTAN AND PARTS OF THE

BRONX, BROOKLYN AND QUEENS

SAO PAULO MEXICO

DENSITY PATTERN SIMILAR

SKYLINE IS DOMINATED BY HIGH RISE.

MULTICENTERED

SKYLINE IS CONSISTENTLY LOW

MULTICENTERED

URBAN FORM AND DENSITY ARE DIFFERENT CONCEPTS.

Similar density profiles shows how high-rise buildings do not necessarily

create higher density in comparison to more tightly planned low-rise

development


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Extremes of wealth and poverty as shown

here on the edge of the Paraispolis favela,So Paulo,represent deep inequalities in the


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Moving in the city

Delhi

Mumbai

Kolkata

Bangalore

New York

Shanghai

London Mexico

Johannesburg Berlin



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All cities under study have a higher Human Development Index (HDI) than their national data.

The HDI score combines life expectancy, literacy rate, educational enrolment ratio with its per

capita Gross Domestic Product to provide a snapshot of the quality of life in each city.



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Density as a planning tool - India

INTEGRAL COMPONENT OF URBAN PLANNING

Mostly ignored in India

Has led to further sprawls No one size fits all where density is concerned

Indian cities need to see what fits their requirement

Socio-economic characteristics of density have an important role to play in

India

Master Plans do not incorporate density as a tool for development,

large programs like JNNURM are promoting densification of inner core

Resulting policy gaps needs to be addressed

QOL IMPROVES AS DENSITY INCREASES TILL A TIPPING POINT;

Moderate to high density neighborhoods are more likely to have better

access to services and facilities; they are also more likely to feel more secure. Density patterns have a strong linkage to income distribution.

Higher income category populations prefer to stay away from city center in low

to moderate density areas

Lower income category prefer to stay near city center


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Master plan analysis


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Issues related to various densities

Low density issues

large regions with low density development is considered to beunsustainable as it results in

urban sprawl,

involves high infrastructure costs,

stretches the resources of social services and facilities.

It reduces the economy of public transport systems and dwellers tend to

rely on private car use with resulting increases in emissions, fumes, lossof air quality, and in a way or other it results in social isolation.

Typical lot configurations for low density (12.5 dwellings/ha)

Source: Development Code Precinct Planning, The Growth Centres

The sprawl and greater

urban footprint associated

with low density

development can also putpressure on the natural

environment, threatening

existing eco systems and

bio-diversity, and can impact

on the use of productive land

for agricultural purposes.


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Medium density issues

Housing types associated with medium density housing development can cater

for the needs of a range ofdemographic and socio-economic profiles.The increase in density effectively results in

lower costs per unit of producing dwellings, as well as a more efficient use of

scarce land resources, infrastructure and social services and facilities.

lack of private open space is normally can be countered by creating communal

open spaces or parks to offer recreational opportunities and amenities for

dwellers.

Typical lot configuration for medium density (20.69 dwellings/ha)Source: Development Code Precinct Planning, The Growth Centres

Denser development

where dwellings are placed

and residents live in close

proximity to each other in

tighter spaces brings with it

issues that are lesscommon in low density

development issues such

as privacy, adequacy of

private open space, solar

access (natural light),

issues of parking etc.


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High density issues

In order to achieve the total requirement of land, high density development playsvital role and hence more open area within the built fabric and agricultural

land can be protected.

High density development close to activity centres and public transport

routes represents the most efficient use of urban resources. It generates

the smallest ecological footprint of all three density types.

High density development generates similar issues to medium density

development, although, at a much more intense scale.

The issues of privacy, solar access and car parking can be dealt with in

the design of buildings; and lack of private open space can be resolved by

provision of communal open space and parks.

With high density development, bulk and height of buildings, createhindrance for open space around it and other buildings nearby, and spaces

between buildings are issues that can be dealt with by appropriate siting

and the arrangement of buildings blocks.


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Typical lot configuration for high density (38.55 dwellings/ha)Source: Development Code Precinct Planning, The Growth Centres Commission

To achieve the best outcome, the planning and layout of the blocks in the

master planning stage must ensure appropriate block sizes,

configurations and orientation to allow future buildings to be designedand sited on these blocks to optimum effect.

Another issue associated with high density development is the increase in

opportunity for anti-social behavior and crime due to increased

population density, increased unrecognizability and higher

concentration of different social mixes.

The planning and layout of the area must be developed such that all blocks

face towards streets or public open spaces.


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Analysis


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Comparison of FAR regulations


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Case - Mumbai FAR regulations

Mumbai FSI values are very different from most major cities around the world. InMumbai FSI values are: Very low Not differentiated between commercial and residential Uniform over very large areas

not reflecting the difference in accessibility around train stations not linked to land market values

0.0 10.0 20.0

New York

Manhattan

Shanghai

ChennaiNoida

Delhi

Mumbai

Bangalore

Gurgaon

Pune

FAR across cities


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We can make some conclusion on basis ofdifferent density studies to establish our

choices of using suitable density.

Higher residential densities should be located near activity centres and along

public transport routes to maximize access and convenience to services.

Medium density should be assigned to locations ofhigh amenity, which may

coincide with activity centres or neighbourhood parks, such as open space

corridors, nature reserves, lake/ water side, as well as in close proximity to public

transport routes.

The remaining residential areas can be allocated to lower density housing forms,

with the lowest density located at the fringes of a city bordering non-urban areas.

The choice of locations for different densities is also influenced by the site

topography. Slopes of greater than 20% are generally not considered suitable for

medium density development due to excessive retaining requirements adding to extra

costs.

Choice of appropriate densities


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A LANDSCAPE ECOLOGY APPROACH TO SUSTAINABLE

DEVELOPMENT IN RELATION TO HOUSING DENSITY

Residential development should be designed with the existing environment

a) Density and zoning: distribution of facilities in an area have implications on

its intensity of use and utility.

b) Density and land consumption: land is a finite resource. Increasing

density in an area conserves land.

c) Density and transport: high density encourages commercial

development, and job opportunities. The need for the car decreases as

services, amenities and employment are brought closer to home.

Clustered communities promotes higher transit ridership and shorter trip

lengths between home, work and social activities.

S t i bilit d R l f d it


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Sustainability and Role of density

DENSITY AND INFRASTRUCTURE COSTS

Higher densities and effective redevelopment can reduce public costs. Compared tolower density developments, higher density compact neighbourhoods can reduce both

the capital and operating costs for police, fire, waste collection and disposal, water

supply, sanitary and storm sewers.

DENSITY AND COMMUNITY INTERACTION

Lower density developments encourage dispersed land use patterns and often reduce

community interaction by increasing the distance from the home to work, services,

friends and family. High density residential neighbourhoods facilitate a greater mix of

land uses, which encourages young children, youth, adults and elderly people to move

out and interact without having to go too far away from home. High density housing

increases the amount of public space available by building on less land.

DENSITY AND HOUSING MIX/ TYPE

Increased density facilitate the development of a greater mix of housing form.


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0

20

40

60

80

100

DetachedHouse

End ofTerraceHouse

Top FloorFlat

Centre ofTerraceHouse

CentreFloor Flat

This comparison of Energy Use by HouseType (assuming Equal Floor Area and

Orientation) shows the importance ofDensity to

Sustainable Development

Energy

0

20

40

60

80

100

120

Apartment Single- family unit

Graph showing comparitive cost percentages ofland and infrastructure development

Cost of infrastructuredeve.

Cost of land

density and urban form

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