11

The Ideal Road Density for Small Islands

S. C. LinDepartment of Construction EngineeringNational Kinmen Institute of Technology

22

The Ideal Road Density for Small Islands

Outlines1. Where and what is Kinmen2. Theory of Biogeography3. Modeling the ideal road density4. The results5. Discussions

33

Taiwan

China

Kinmen

Geographic location of Kinmen

Kinmen !

44Basic Data of Kinmen and Taiwan

KinmenTotal area 150.5 km2

Population 61,215 Area of Main Kinmen Island 134.25 km2

TaiwanTotal area 36,188 km2 Population 22,610,00

Kinmen !

55Road System of Kinmen (1)Road System of Kinmen (1)

Kinmen !

66Road System of Kinmen (2)Road System of Kinmen (2)

Kinmen !

77

Major Road System of Kinmen Major Road System of Kinmen (3)(3)

Kinmen !

88Theory of Island Biogeography

Relation of number of species and area

S = C AZ

S: Number of species

A: Area of the island

MacAurthur & Wilson

Z = 0.24 ~ 0.34

Theory !

99

Relation of number of species and area

S = C AZ

Theory !

ZKM = 0.324 (Kinmen)

Theory of Island Biogeography

324.0

188,36

5.134log

137

22log

KMZ

1010

Density of species for each half = 0.8/0.5 =1.6

Theory !

Theory of Island Biogeography

1111

Road type ConcreteAsphalt Concrete

UnpavedTank

DrivewayTotal

Length 129.9 214.4 18.2 7.3 369.8

Total length of serving roads in Kinmen (unit: km)

Theory !

1212

Population(Thousand)

Area(km2)

Total length of road system

(km)

Number of vehicles

(Thousand)

Vehicle/Total length of roads

Vehicle per capita

Road density

(km/km2)

Kinmen 61 150.5 343.9 13.0 37.8 0.21 2.29

Taiwan[28](Non-metropolitan) 22,610

(overall)

34,818 20,102

6,134(overall)

160.6(overall)

0.27(overall)

0.58

Taiwan(overall)

36,188 38,202 1.06

Okinawa, Japan[23]

1,352 2,271 1,455 552 379.4 0.41 0.64

Netherlands[24] 16,193 33,920 114,427 7,894 69.0 0.49 3.37

USA[25] 292,936 9,372,614 6,297,966 230,428 36.6 0.79 0.67

Roads density in different areas

Theory !

1313

Ideal Road density in continent areas

Studies and field investigations showed that the highest road density wolves can tolerant to maintain their healthy population is ρwolf = 0.6 km/km2

Why?

Theory !

1414

Food web pyramid

Theory !

1515

Ideal Road density for Kinmen

What is the ideal road density for Kinmen ?Three models:1.Direct application of ρ= 0.6 km/km2

2.Model island model3.Largest small island model

Model !

1616

Model island modelTake Okinawa as a model island to KinmenSk is number of species of KinmenSO is number of species of same taxon in OkinawaZ = 0.324

324.0

324.0

O

K

O

K

CA

CA

S

Sn

n = 0.41

Model !

1717

Model island model

O

O

O

O

K

O

K

K

A

S

A

S

A

nS

A

SD 2.6

271,2

15041.0

the density of species in Kinmen D

Model !

1818

Model island model

Unit cell

Roads

LL

L 222

Road Density

Model !

Road Mesh

1919

Model island model

The road density of Okinawa is ρO=0.64 km/km2 that leads to L=3.125 km and the area of the unit cell is then (AO) =L2 = 9.766 km2

To make same species density in Kinmen, enlarging the area of unit cell to 6.2 times for Kinmen’s is necessary.

Model !

2020

Model island model

Therefore the area of Kinmen’s unit cell is(AK) ＝ 6.2 × 9.766 ＝ 60.55 km2. and length of the cell LK = (AK) 1/2 = 7.78 km.

The ideal road density of Kinmen could be obtained as ρKM = 2/LK = 2/7.78 = 0.257 km/km2

Model !

2121

Largest small island model

Take Largest small island as a model island to Kinmen

Largest small islandArea = 1,000 km2 Population = 1,000,000

Follow the same procedure, we haveρKM = 0.316 km/km2

Model !

2222

Ideal Road density for Kinmen ?

Model 1 2 3Kinmen Cu

rrent

Obtained RoaObtained Road Density d Density ρρKM KM

(km/km2)0.60 0.257 0.316 2.290

Results !

2323

Transportation Policy of Kinmen ?Discussions !

2424

Three Principles of Road Construction

1. Avoidance Stop building roads, Remove roads,

Put roads underground, Change the routes

2. Mitigation Make animal corridors, Reduce noises and disturbance,

Use ecological friendly construction materials,

Use cleaner fuel

3. Compensation Create protected areas, Restore destructed habitats,

Enhance habitat conditions

Discussions !

2525

The End