Risk-based land use and spatial planning

Miho OHARA

International Centre for Water Hazards and Risk

Management (ICHARM)

Public Works Research Institute （PWRI), Japan

Under the auspices of UNESCO

Introduction of ICHARM

International Centre for Water Hazards and Risk Management (ICHARM)

was officially established as a UNESCO category II center and a part of the

Public Works Research Institute of Japan on March 6, 2006.

Efficient Information

Networking

Effective Capacity

Building

Innovative Research Flood modeling

and simulation Risk Assessment

Hazard Assessment

Workshop Training Master and PhD students

Risk-based land use and spatial planning

Data & Statistics

Risk Assessment & Risk Identification

Building Social Consensus for Identification of Target Hazard

Land Use and

Spatial Planning

Contribution from

Private Sector

Final Goal: Disaster Risk Reduction

Combination with Other Countermeasures

Understanding from

Citizens

1. Example of Risk-based Approach after the 2011 Great East Japan Earthquake in Japan

-As a consequence of gigantic tsunamis which hit the Pacific coast of Japan, 19,535 people died and 2,585 are still missing as of March 2017.

Two Target Levels of Tsunami

Level 1 Tsunami: Frequent tsunami

Level 2 Tsunami: Largest scale tsunami

Damaged levee due to 2011 tsunami

Adopted by Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and translated by ICHARM

Levee before 2011 tsunami

Levee improved after 2011 tsunami

The height of tsunami at 2011 event

I tegrated easures o i i g structural and non-structural measures.

Land subsidence

Role of National and Local Gover e ts for Build Ba k Better

National Level: Legal framework of Disaster Risk Area by Building Standard Act.

Local government Level: Designation of Disaster Risk Area by ordinances

Relocation Projects for residences to move to safer land.

Evacuation Tower Disaster Risk Area

Outside Disaster Risk Area R

oa

d

Schools, Hospitals, Evacuation space Houses,

Evacuation facility

Ele

vate

d

Ro

ad

Factory, Park

(No house)

Lev

ee

Leve

e

Levee for protecting

Level 1 tsunami Ishinomaki City

Current Status of Relocation to Safer Land

-Relocations are still underway.

-By March, 2017, almost 90% of

the land development for

relocation has been done.

-By March, 2018, it is scheduled

to be completed.

Land Development of Relocation

Adopted by Reconstruction Agency Disaster Risk Area

Act for Tsunami-Resilient Cities (2011)

-A new act for tsunami-resilient cities was enacted in order to reduce tsunami disaster risk in all coastal areas in Japan.

Adopted by Ministry of Land, Infrastructure, Transport and Tourism (MLIT) and translated by ICHARM

2. Example of Practical Approach by Local Government Considering Flood Inundation Probability

-Shiga Prefecture adopted a unique policy for integrated flood management considering flood inundation probability in land use planning.

10 Year Return Period 100 Year Return Period 200 Year Return Period

Laser-scanned Precise Elevation Map High-resolution Inundation Simulation

Precise Flood Inundation Mapping

Adopted by Shiga Prefectural Government and translated by ICHARM

Risk Matrix for Land Use Planning -Shiga Prefe ture is o du ti g la d use pla i g usi g Risk Matrix . La d use is determined according to the inundation probability and inundation level.

https://www.e3s-conferences.org/articles/e3sconf/pdf/2016/02/e3sconf_flood2016_13008.pdf

1/ 2 (0.500)

1/ 10 (0.100)

1/ 30 (0.033)

1/ 50 (0.020)

1/100 (0.010)

1/200 (0.005)

------

Inundation Level

h<0.1m 0.1<h

<0.5m

0.5<h

<3.0m

h>=3.0

m

Inu

nd

atio

n P

rob

ab

ility

If an inundation of over 50 centimeters deep is expected to occur more than once in 10 years, the area will be taken off the list of areas for future urbanization.

If an inundation of over 3 meters deep is expected to occur more than once in 200 years, the area is designated as Flood Risk Zo e, with building regulation.

High Risk

Low Risk

Conclusions National Level

• Legal framework for ensuring sustainability

• Science and technology for risk assessment to identify and

monitor risk

• Building consensus for identification of target hazard level

• Realizatio of Build Ba k Better

Local Government Level

• More risk sensitive land use and spatial planning

• Combination with other countermeasures such as evacuation,

multiple uses of infrastructures, etc.

International Cooperation

• Information sharing of good practices

• Training of engineers and practitioners

http://www.icharm.pwri.go.jp/