Applying Hazard Maps to Urban Planning

September 10th, 2014

SAKAI Yuko

Disaster Management Expert

JICA Study Team for the Metro Cebu Roadmap

Study on the Sustainable Urban Development 1

Contents

1. Outline of Metro Cebu Roadmap Study

2. Development of GIS Database

3. Methodology of Development Suitability

Analysis

4. Preparation of Thematic Maps

5. Overlay Analysis

6. Necessary Actions

2

1. Metropolitan Development

Framework

2. Roadmap Development

Plans

3. Short-term Priority Projects

3

Vision Roadmap

1.1 Roadmap Toward The Vision

1. To draw up a roadmap and detailed action plans

based on “Mega Cebu Vision 2050” with time-

framework of:

Short-term (2016),

Med-term (2020), and

Long term (up to 2030 up to 2050)

2. To formulate priority projects in association with

institutional and organizational options for the

materialization

4

1.2 Objectives of the Study

The study area covers Metro

Cebu consisting of 13 LGUs :

• 7 cities (Cebu, Danao,

Mandaue, Lapu-Lapu, Talisay,

Naga and Carcar) and

• 6 municipalities (Compostela,

Liloan, Consolacion, Cordova,

Minglanilla and San

Fernando).

Danao, San Fernando and Carcar

are new comers to the old Metro

Cebu boundary

5

1.3 Study Area

Metro Cebu

72 km

6

LGUs

Land Area

(km2)

Population Population Growth

Rate (%/year)

2000 2007 2010 ’00-‘07 ’07-‘10

Cit

ies

Cebu 315 718,821 798,809 866,171 1.5 2.7

Lapu-Lapu 58 217,019 292,530 350,467 4.4 6.2

Mandaue 25 259,728 318,575 331,320 3.0 1.3

Talisay 40 148,110 179,359 200,772 2.8 3.8

Danao 107 98,781 109,354 119,252 1.5 2.9

Carcar 117 89,199 100,632 107,323 1.7 2.2

Naga 102 80,189 96,163 101,571 2.5 2.2

Mu

nic

ipa

liti

es

Compostela 54 31,446 39,167 42,574 3.2 2.8

Consolacion 147 62,296 87,544 106,649 5.0 6.8

Cordova 17 34,032 45,066 50,353 4.1 3.8

Liloan 46 64,970 92,181 100,500 5.1 2.9

Minglanilla 66 77,268 101,585 113,178 4.0 3.7

San Fernando 69 48,235 54,932 60,970 1.9 3.5

Metro Cebu 1,163 1,930,096 2,314,897 2,551,100 2.6 3.3

Philippines 343,448 76,506,928 88,566,732 92,337,852 2.1 1.4

Source: PS

1.4 DEMOGRAPHIC FRAME

2. TECHNICAL APPROACHES

7

4 Strategies 7 Sub-roadmaps 1 Metropolitan

Competitiveness

Enhancement

Competitiveness

2 Urban Structure and Land

Use

Mobility

3 Urban Transport and

Highway Network

4 Water Supply and Disposal

Management

Livability

5 Solid Waste Management

Metropolitan

Management

6 Smart SRP Development

7 Metropolitan Administration

1.5 Roadmap Development Plans

An Overall

Roadmap integrating

7 sub-roadmaps

Schedule Work Items Participatory Activity

Ph

as

e 1

11

12

2014/1

2

3

1.6 Work Plan of Phase 1

1st Seminar

1st Workshop

I-1. Preparatory Works

I-2. Analysis of Existing Conditions and Issues

I-6. Finalization of Phase I Activities

I-3. Conceptual

Roadmap

towards

2030 and

2050

I-4. Preparation

of Short-

term Priority

Projects

I-5.

Conduct of

Home

Interview

Survey

Schedule Work Items Training

Ph

as

e 2

4

5

6

7

8

9

10

11

12

2015/1

2/3

1.7 Work Plan of Phase 2

2nd Seminar

2nd Workshop

II-12. Study Finalization

1st Training in Japan

2nd Training in

Japan

II-1. Development Frameworks for Sub-roadmap Planning Works

II-2. Metropolitan

Competitiveness

II-3

Urban

Spatial

Planning

II-4

Urban

Transport

Network

II-5.

Water Supply

and Disposal

Management

II-6

Solid Waste

Management

II-10. Overall Evaluation of Mega Cebu Roadmap

II-8. Sub-roadmap for Smart SRP

Development II-9. Sub-roadmap for Metropolitan

Administration

II-7. Intermediate Wrap-up of Roadmap Works

II-11. Finalization of Phase II Activities

Comments from the Philippine

Side

2. Development of GIS Database

• Purchase of satellite image with resolution of 0.6m

• Preparation of Topographic Map in 1:10,000 based on the

satellite image and LIDAR with the following specification

10

Items Specification Attribute

1 Roads Center line, road edge line Name, Width (m)

2 Water River bank line, canal line, coastal line -

3 Contour 1m interval line in coastal area and 5m

interval line in the rest areas

Height (m)

4 Vegetation Polygon Type (agriculture, forest, shrub

and pasture, vacant land,

mangrove, wetland, sand,

urbanized area, and others)

5 Building Footprint in polygon, smaller buildings in

point

Name of public facility building

6 Public

Facilities

Location and area of school, hospital,

government office, fire station, police, church

and park

Name

3. Methodology of Development Suitability Analysis

11

Land Use

Development Suitable Area

Natural Disaster Hazards Constraints

Topographic Maps and Data from Relevant Agencies

Flood Earthquake Landslide Mountain Area Sea Level Rise

1st Processing: Thematic Maps

Slope

2nd Processing: Overlay and Grid Analysis

3rd Processing: Grid Analysis

• Thematic maps: Those are prepared using topographic

map in 1:10,000 and data from relevant agencies.

• Overlay analysis: That is implemented to clarify the

critical areas for development caused by constraints and

natural disaster hazards.

• Grid analysis: That is implemented to accumulate the

assessment scores of constraints and natural disaster

hazards.

• Development suitable area shall be provided for future

urban development. Those areas should be defined in

urban planning map accurately.

12

4. Preparation of Thematic Maps and Hazard Maps

1) Existing Land Use

2) Slope and Mountain Areas

3) Sea-level Rise Hazard

4) Flood Hazard

5) Landslide Hazard

6) Earthquake Hazard

13

- 1m, 3m: Caused by Expected Climate Change by

NAMRIA

1) Existing Land Use

• 15% of Metro Cebu’s land

has been urbanized.

14

2) Slope and Mountain Areas

• Construction in steep

slope area more than

18% is restricted.

These areas and

mountain areas are

covering 72% of the

Study Area.

15

3) Sea-level Rise

• 1m, 3m: Caused by

expected climate

change scenario,

covering 0.04%, 0.3%

of the Study Area

16

4) Geo-Hazard

• MGB provided the Geo-

hazard map in 1:50,000

only because they are

still compiling the results

of field survey of 1:10,000

map.

• Therefore, JICA Study

Team conducted hazard

mapping using our GIS

database and assessed

flood and landslide

hazards in 3 levels.

17

5) Flood Hazard

• Flood hazard level was

assessed based on river

flow simulation targeting

14 rivers of which river

basin spreads more than

10km2 and covered the

expected flood scale over

once a 50 years return

period.

18

Hazard Level Definition

Low (blue) Flood is expected to be occurred (Alluvial Plain)

Moderate (yellow) Sheet flood and drainage-caused flood

High (red) Flash flood and road embankment-caused flood (possible to

take a long flood duration)

5) Landslide Hazard

• Landslide hazard area was

assessed based on interpretation

of remotely sensed data from

satellite image, digital terrain

model (DTM) and contours. This

work followed the MGB criteria for

landslide susceptibility.

19

Hazard Level Typical Areas

Low Slope gradients are below 18 degrees

Moderate Slope gradients are 18-35 degrees

High and Very

High

Steep to very steep slopes (>35 degrees) and evident active

landslides, where inactive landslides are evident (old landslide

debris deposits, collapsed sinkholes, old landslide complexes),

actively worked mining areas, high erosion along the riverbanks

6) Earthquake Hazard

• Original maps comes from responsible agencies and digitized by JICA

Study Team.

• Earthquake hazard will be assessed using grid analysis methodology which

gives scores for each grid according to hazard level and accumulate the

scores in same cell and reclassified. The grid size will be 250m x 250m.

20

5. Overlay Analysis

1) Existing Land Use and

Hazard Map

• Urbanized area which is

overlaid by hazard area

amount to 1.9% of the

Study Area.

21

2) Public Facilities and Hazard Map

• Location of public facilities

can be assessed using

hazard map by overlaying

several layers.

• Those facilities located in

hazardous areas should be

prioritized for disaster

resistant construction.

22

6. Necessary Actions • Development Control System should be achieved by laws and

enforcement system.

• Disaster Management Master Plan should be prepared based on risk

assessment using detailed and accurate maps. It should include

identification of shelters and emergency transport road network.

• Securement of Public Facilities should be implemented based on

development of strategy for site and structural safety of public

facilities, including existing facilities.

• Integrated Data Sharing System should be developed to share

outputs of hazard maps and GIS analysis within government

agencies and relevant organizations. It should be updated and

maintenance periodically.

Further assessment will be implemented in the following phase,

applying population density and infrastructure & social service level

indicators. At last, a future land use plan will be proposed. 23

Thank you…

24