Modelling urban expansion scenarios in Beijing, China ...

Seminar in Thailand , Jan 16, 2009

Dr. Chunyang He

Modelling urban expansion scenarios in Beijing, China under the restriction of the

water resource and land use policy

College of Resources Science & Technology, Beijing Normal University, the People’s Republic of China, Beijing, 100875, China

http://www.beijing-2008.org http://www.bnu.edu.cn http://www.irs.bnu.edu.cn

Outline1. Research Background2. Description of our newly developed UES

model3. Implementation of the UES model for

Beijing 4. Discussion and conclusion

Beijing, China’s capital

48

5

6

17 2

3

Yanqing

HuairouMiyun

ChangpingShunyi

Pinggu

Mengtougou

FangshanDaxing

Tongzhou

Legend

Ringroad

Highway

Sub-center

city

1

2

3

4

Xicheng

Dongcheng

Xuanwu

Chongwen

5

6

7

8

Haidian

Chaoyang

Shijingshan

Fengtai

Longitudes:115°25′ - 117°30′ E Latitudes: 39°28′- 41°25′ NArea: 16800 Km2

GDP(2004): 428.3 billion RMBPopulation(2004):14.93 million

Beijing experienced fast development since 1978

Population GDP

1979 8.97 12.01 56.86 4.30 70.92 24.78

2004 14.93 428.33 73.50 2.40 37.60 60.00

(million person) (billion Yuan)Urbanization

Level(%)Year Agriculture(%)

Industry(%)

Service(%)

1

2

1

2

1

2

1

2

1

2

1

2

MSS (May 5, 1975) TM (Oct. 2, 1984) TM (May 6, 1991)

TM (May. 15, 1997) ETM+ (May 19, 2001) TM (May. 19, 2004)

Forbidden City1 2 Summer Palace

Beijing’s problem: continuous city expansion to form a “big pancake” by encroaching good cultivated land and green space in the

urban/rural fringe area

“Mam, I only wanta little clean water”

Beijing’s problem: Water shortage is obvious in Beijing

Only 19.2% of the national average

We are thirsty!

Only 3.5% of the world average

1 Research background and Objective

Question:

How to plan Beijing’s development under the restriction of land resource and water resource?Objective:

(1)Develop a new urban expansion Scenarios (UES ) model by coupling a System Dynamic (SD) model and a Cellular Automata (CA) model

(2)Modelling urban expansion scenarios in Beijing, China under the restriction of the water resource and land use policy


2 Description of our newly developed UES model


UES is one urban expansion scenarios model developed by us.UES is one convenient tool that can spatially and explicitly model the urban expansion patterns under the different “what-if” scenarios of urban land planning policies.UES tries to contribute to the need for planning-based visualization and decision-support tools.

What’s UES?


The basic idea of UES is to couple system dynamics (SD) model and CA (Cellular automata) model to represent the urban expansion process.

Basic ideas of UES

Socio-economicforces at macro scales

Land use suitability, neighborhood effect and inheritance at local facotrs

Complexity of driving forces at macro scales

SD model

Complexity of Land pattern evolution at local scales

CA model

UESUrban expansionprocess

Urban Land use area

Urban Land use Location

Urban expansionprocess

Urban Land use area




Urban Land use area



The general structure of UES

Urban Land supply

SD modelCA

Urban Land locationUrban land area

Demand-supply balanceurban land demand Scenarios

Scenarios urban land pattern

Technology

Population

Economy

Market

Land policy

Local factors

National/regional factors

Suitability

Neighborhood effect

Constraint of natural resource

Environmental constraint

Planning constraint

Inherited attribute

Driving forces resistant forces

The urban land demand scenario module based on a SD model

Framework of land use SD model

Land for population

Land demand of urban expansion

Population increasing rate Resident

population+

Water resource

Land for public service

Industrial production

－

+

+

Land for industry

+

－

Urbanization

+

+

Industrial water use efficiency

Technology advancement

++

+

GDP increasing rate

－ +

+

+Floating

population

++

－+

+

Maximum carrying capacity to industry

Maximum carrying capacity to population

-

- +

+

Land for population

Land demand of urban expansion

Population increasing rate Resident

population+

Water resource

Land for public service

Industrial production

－

+

+

Land for industry

+

－

Urbanization

+

+

Industrial water use efficiency

Technology advancement

++

+

GDP increasing rate

－ +

+

+Floating

population

++

－+

+

Maximum carrying capacity to industry

Maximum carrying capacity to population

-

- +

+

The urban land allocation module based on a CA model

Driving Forces (DF) Stochastic Perturbation (SP)Resistant Forces (RF)

The probability that cell (x,y) with land use type K is occupied byurban expansion at time t , is a function of the driving forces , theresistant forces and a stochastic perturbation . It can be expressed as:

)3(),,( ,,,,, yxt

yxt

yxt

yxKt VRDfP =

RF

SP

DF

Urban land pattern allocation by CA model

Probability

=

Time Loop&

Stochastic perturbation

0 0.5 1

[ ]( )αrandvt ln1 −+=Allocation Rule

The cell with the highest possibility is selected as that would be

occupied by urban expansion .

Suitability Inherited attribute

Neighborhood

)7()( ,1 1

,,,,

2

1,,,1,,,, yx

t

r lyxl

tyxr

tm

iyxK

tmyx

tmyxi

ti

tyxK

t VPCECIWNWSWP ××××−×+×= ∏ ∏∑= =

−

=−

Environmental constraints Land policy

Urban exapnsionat time T

Urban expansionat time T+1


3 Implementation of the UES model for Beijing

0 40 Kilometers1 Yanqing

2004

31

2

45

611

10

9

7

8

1997

31

2

45

611

10

9

7

8

1991

31

2

45

611

10

9

7

8

High density urban landLow density urban land

Cultivated land

Water areaForest land

Shrub land

2000

31

2

45

611

10

9

7

8

2 Huairou 3 Miyun 4 Pinggu 5 Changping

6 Shunyi 7 Mengtougou 8 Fangshan 9 Daxing 10 Tongzhou 11 Capital city

Land use/cover change in Beijing from 1991 to 1997 based on remotely

sensed data

(a) Simulated urban (Kappa 0.73)

(b) Actual urban pattern

(c) Simulated urban (Kappa 0.76)

(d) Actual urban pattern

(e) Simulated urban (Kappa 0.80)

(f) Actual urban pattern

Expressway Ringroad Administrative boundary Urban area0 40 Kilometers0 - 184 m 184 – 441 m 441 - 717 m 717 - 1075 m 1075 - 2219 m

Urban growth simulation in Beijing from 1991 to 2004

1997

1997

2000

2000

2004

2004

Predictions of water supply and the selected scenarios of water resources limitation to urban development in Beijing till 2020

Table 2 Predictions of water supply in Beijing till 2020

Year Surface Water

(SW)(108m3)

Utilized rate of SW(%)

Available Groundwater

(AGW)(108m3)

Utilized rate of AGW (%)

Recycling utilized water

(108m3)

Diverted water

(108m3)

Available water supply (108m3)

Data source

2000 13.25 65.08 27.15 156.76 3.52 0.00 43.92 ① 2020 15.26 75.00 18.32 105.77 5.10 11.07 49.75 ① 2020 15.26 75.00 18.32 105.77 5.10 12.44 51.12 ② 2020 15.26 75.00 18.32 105.77 5.10 16.32 55.00 ② Note: ① represents the data from Run, et al.(2004). ② represents the data from Beijing Municipal Government (2005).

Scenario A:slightly limited with 55*108 m3 water supplied in 2020; Scenario B: limited with 51.12*108 m3 water supplied in 2020; Scenario C: obviously limited with 49.75*108 m3 water supplied in 2020.

Three scenarios :

Historical urban land changes from 1991 to 2004 and the urban land demand scenarios under the different restrictions of water shortage

in Beijing till 2020

Year Scenario A (km2) Scenario B (km2) Scenario C (km2)

1991 1206.47 1206.47 1206.47

1997 1870.79 1870.79 1870.79

2000 2331.88 2331.88 2331.88

2004 2726.66 2726.66 2726.66

2007 3073.84 2995.87 2874.74

2010 3452.34 3332.31 3207.10

2015 3659.88 3515.64 3284.53

2020 3895.01 3732.36 3380.82

2007

2010 2015 2020

0 40Kilometers

Expressway Ringroad Administrative boundary

Urban area

0 - 184 m 184 – 441 m 441 - 717 m 717 - 1075 m

1075 - 2219 m

Urban expansion scenario in Beijing from 2007 to 2020 without the

restriction of urban planning policy

0 40Kilometers


Urban area

0 - 184 m 184 – 441 m 441 - 717 m 717 - 1075 m

1075 - 2219 m

Urban expansion scenario in Beijing from 2007 to 2020 under the

restriction of high-yield farmland protection area

2007

2010 2015 2020

0 40Kilometers


Urban area

0 - 184 m 184 – 441 m 441 - 717 m 717 - 1075 m

1075 - 2219 m

Urban expansion scenario in Beijing from 2007 to 2020 under the

restriction of the “green belt”

2007

2010 2015 2020

0 40Kilometers


Urban area

0 - 184 m 184 – 441 m 441 - 717 m 717 - 1075 m

1075 - 2219 m

Urban expansion scenario in Beijing from 2007 to 2020 under the restriction of both the “green belt” and high-yield

farmland protection area

2007

2010 2015 2020


4 Conclusion and Discussion

Conclusion and discussion

(1)The UES model can not only reflect the complicated factors influencing urban expansion at the macroscopic scale but also possess the strong ability to represent land use evolution at the local scale.

(2)AS a tool that aims at implementing “what-if” scenario analysis of urban expansion, it is convenient for the UES model to simulate the many urban expansion scenarios in the near future.

The UES model contributes to the need for planning-based visualization and decision-support tools

Urban land planning policies that focus on only the areas within the administrative boundary of Beijing are limited in their capabilities.

It may be time for Beijing to transfer part of its economic responsibility to the neighbor cities according to the jointly regional development of the macroscopic region of Beijing, Tianjin and Hebei province.

Conclusion and discussionThere exists a big dilemma of the continuous urban expansion versus

limited water resources and environment deterioration in Beijing

Conclusion and discussion

The scenario-based results from the UES model should not be interpreted as forecasts of future events

•Rather, they just indicate possible patterns of urban expansion under the different “what-if” scenarios.

•In fact, the exploration of possible urban expansion patterns and the identification of ‘hot spots’ can be seen as an instrument to support urban land planning policy.

Thank you!!

Happy Chinese New Year !

1 What’s Beijing’s dilemma?

The population of China will increase from 1.2 billion to 1.6 billion with the urbanization level from current 30.9% up to about 50% in 2050, which means over 0.4 billion people, about total population of current of Japan and U.S.A, will move from rural area to urban area in China in next 50 years (Chen et al, 1999).

China’s fast urbanization is challenging not only herself but also the world

Food security Energy consumption

Environment deterioration


The general introduction of CA model

Transition rule

Sijt+1Nij

tSij

t

F,T

CA (Cellular Automata) model is one dynamics model with the local interaction to reflect evolution of the whole system, which can represent spatial pattern of land use in a very realistic way.

Where, is the situation in t+1 of the cell ij, is the situation in t of the cell ij, is the neighbor effect of the cell ij and T is the transition rule.

),,(1 TNSfS tij

tij

tij =+

tijN

Sijt+1 Sij

t

But as one “bottom-up” model, CA’s ability to represent well those macro-scale political, economic and cultural driving forces is limited


The general introduction of SD model

System dynamics (SD) model can not only describe the complicated connections among each element in different levels, but also can deal with dynamical processes with feedback. But SD model’s ability to represent the spatial process is weak

Calibrated weights for the periods of 1991-1994, 1997-2000 and 2000-2004

Factors of driving forces /resistant forces

Weights for 1991-1997 simulation



Distance to expressway 3 4 5

Distance to Ring Roads 9 12 13

Distance to railway 2 3 3

Distance to highway 3 3 3

Distance to airport 2 2 3

Distance to central city 17 14 13

Distance to sub-cities 6 8 9

Slope 2 3 5

Neighborhood effect 52 46 40

Inherited attribute of the occupied land 4 5 6


Basic Hypothesis of UES


Urban Land use area


Socio-economicforces at macro scales

Land use suitability, neighborhood effect and inherited attribute at local scales

Basic Hypothesis of UES

Modelling urban expansion scenarios in Beijing, China ...

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