Transcript Environmental challenges of urban growth: The case of

Urban expanding process along the
transport corridor and the policy
framework in Nanjing, China
Chen Shuang, Sophia
Nanjing Institute of Geography and Limnology,
Chinese Academy of Sciencies
Email: [email protected]
Introduction



During the past two decades, cities in
the Yangtze River Delta have
undergone rapid spatial expansion in
relation with economic progress and
population concentration in this area.
The fast urban growth diminishes
arable lands and ecological habitats as
well as generating damaging effects
through such sources as pollution and
human use.
Urban processes must be studied in
order to understand their influences
and minimize the negative effects on
surrounding environment.
Shanghai
Nanjing
1960
1980
Hangzhou
700
600
500
400
300
200
100
0
1950
1970
1990
2000
2010
2007, HKBU
Preliminary hypothesis

The urban area generally extends
from the centre outward with the form
like a fried-egg. The expansion
process is presumed to follow the
cycled phases of expansion along
transport corridors and filling space
between the corridors.
Gu et al., 2000

Rather than land price, policies and residential or firms’ preferences
determine land development and land allocation due to the
municipal government’s monopolisation of land supply in Chinese
cities.
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Objectives

Quantitatively describe urban expansion process;

Investigate trends in land development patterns;

Determine to what extent the land policy and planning
affect land development.
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Urban expansion of Nanjing
1986 Build-up area
1996 Build-up area
2002 Build-up area
Vegetation
water
Nanjing
Area
(km2)
Population
(person)
Population density
(persons per km2)
GDP per person
(US dollar)
6582
5,836,000
887
4130
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Urban Nanjing image 2005
浦口-珠江
Pukou-Zhujiang
new town
仙林 Xianlin
new town
东山 Dongshan
new town
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Location of study area
South site
North site
Delineation
Along the airport Along the
highway lasting Nanjing-Luhe
about 27 km
freeway lasting
from the city wall,about 27 km from
3 km buffer from the Yangtze River,
the way
3 km buffer from
the way
Area
167 km2
160 km2
Administration Yuhua District
Pukou district
Jiangning
Luhe district
District (formerl (original Dachang
Jiangning county)district)
Land /
planning
management
District
government
Municipal
government
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Index and data sources
Description indicator
Definition
Data sources
Urban intensity (UI)
Developed urban area / total area 1986, 1996, 2002 Land use data
in shape file interpreted from TM
Urban expansion speed (UES)
Developed area in a period /
images of Nanjing;
years
2005 Sport 4 satellite image of
Land development structure (LDS) Ratio of residential, public service,
Nanjing;
industrial etc. land use types to
1:50000 topographic map of
the total developed urban area
Nanjing;
Land use efficiency (LUE)
Built-up area / the total area of
Satellite Image Atlas of Nanjing,
developed land
2005;
Urban expansion track (UET)
A series of gravity centre of
Urban master plan of Nanjing
developed land parcels in different 1981-2000;
periods.
Urban master plan of Nanjing
1991-2010;
Mean area of newly developed
Mean area of developed land
land parcels (MANDL)
parcels in a period
Urban master plans of Pukou,
Luhe, Dongshan 2002-2020
Adherence of newly developed
The mean value of developed
land parcel to the built-up area
(ANDL)
land parcels’ nearest distance to
the built-up area in a period.
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Changes of UI and UES
2
9.5
1
0
UI


3
2002
UES
2005
40
35
30
25
17.3
20
15
11.9
13.6
10
5
0
1986
1996
2002
50
45
40
35
30
25
20
15
10
5
0
7
6
32.3
35.5
5
26.1
4
3
16.3
2
UES (sq km/a)
18.3
1996
45
6
4
1986
50
7
5
North site
UI (%)
47.1
42
UI (%)
50
45
40
35
30
25
20
15
10
5
0
Nanjing city
UES (sq km/a)
UI (%)
South site
1
0
1986
1996
UI
2002
2005
UES
The urban area extended at a faster speed in the two sites
comparing with that in the whole city, indicating development
concentration along the transport corridors.
The expansion speed was accelerated from 1996-2002 both for the
south site and the whole city.
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Land development structure
South site
North site
100
100
90
Unused
80
90
80
70
Mixed
land use
60
Industrial
land
50
70
60
50
40
30
20
10


Mixed land use
Industrial land
40
Campus
30
Campus
Residential/public
20
service land
10
Residential/public
service land
0
0
1986-1996
Unused
1996-2002
2002-2005
1986-1996
1996-2002
2002-2005
For the developed land parcels in the three periods, residential/service land
use occupied about 30-70%, industrial land use occupied about 10-50%,
and the other was mixed land use and unused land.
Industrial development within 1996-2002 and campus development within
2002-2005 were the major approach to urban expansion besides residential
development.
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Land use efficiency
100
90
80
70
60
50
40
30
20
10
0
1986-1996
1996-2002
2002-2005
90
80
70
60
50
40
30
20
10
0
area (sq km)

A lot of land has not been used
in the developed parcels
during the fast expansion
period. The efficiency
decreased from over 96% to
about 68%.
The rapid expansion in the
south site is attributed to land
enclosure to some extent.
area (sq km)

1986
1996
Developed area
2002
2005
Built up area
South site
North site
96.4
68.9
68.4
98.5
73
86
90
80
70
60
50
40
30
20
10
0
1986
1996
Developed area
2002
2005
Built up area
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Landscape indicators


The area of land parcels tend to be smaller pieces and the distance to built
up area tend to be shorter in relation to adoption of compact development
pattern.
For the two sites the land parcel was located within 3.5 km to the built up
area.
South site
MANDL (hectare)
North site
86-96
96-02
02-05
86-96
96-02
02-05
66.97
73.59
18.59
56.13
18.52
18.04
379.33
1940.31
0
661.14
3525.48
0
88.26
1115.21
0
79.89
1288.91
0
38.76
761.183
0
55.47
841.724
0
ANDL (m)
Mean
Max
Min
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Urban expansion track
South site
North site
86-96
86-96
96-02
02-05
86-96
96-02
96-02
96-02
02-05
02-05
02-05
02-05
02-05
96-02
86-96
86-96
86-96
96-02
Campus
Industrial
Residential
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Trends of land development patterns
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The expansion speed tend to slow down after
the irrationally quick urban development within
1996-2002 according to the UI and UES
changes.
Residential and public service including
campus development have been becoming the
major approach of urban expansion by the
analysis of land use structure.
The compact land development pattern tend to
come back based on the land use efficiency
calculation and the landscape indicator
analysis.
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Effect of planning on land development
Comparison of practical
land allocation to the
planning


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80-98% of the two sites was
not covered by the master
urban plan within the fast
expansion period.
About 50% of the
development covered by the
plan differed in land use
type.
The coherence frequency
tended to be improved.
4500
4000
3500
Area (hectare)

3000
2500
2000
1500
1000
500
0
S86-96
S96-02
S02-05
N86-96
N96-02
N02-05
Development coherence with the plan
Development different from the plan
Development out of the plan area
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Effect of policy on land development pattern

Differences in development pattern between the two sites with
variant management systems
South site (1986-2005)
North site (1986-2005)
Local decision-making in
planning and land supply
Speed
3.30 km/yr
The portion of campus land
Structure
have been increasing and that
of residential land decreasing.
Efficiency of land use 80.18%
Messed layout, each type of
Landscape
land use parcels equally
distributed at two sides of the
transport line
Municipal decision-making in
planning and land supply
1.68 km/yr
Planning
Effective
Management system
Low efficiency
The portion of residential land have
been increasing
89.36%
Cluster layout, each type of land
use parcels relatively concentrated
and the homogenous clusters
scattered in the site
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Conclusion


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The high resolution satellite images provide abundant
data for quantitatively analysis of urban expansion
process in China. The research on quantitative
description of urban expansion and its driving forces is
important and realizable.
The local government largely influenced urban land
development but the decision maker are short of relevant
supporting knowledge of land allocation.
Residential/firms preferences for transport or amenity
would be studied later quantitatively.
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The End
and Thanks!
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