study report of questionnaire for the project on urban flood risk management in tc region liu zhiyu...
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Study Report of QUESTIONNAIRE
For the project on Urban Flood Risk Management in TC Region
LIU ZhiyuCHEN Zuhua
BOH, MWR, CHINA
Sept. 2010
Study Report of QUESTIONNAIRE
Background 1
Outline of pilot cities & Recent floods in the cities2
Good Practices in Urban Flood Management3
Background• According to the discussion in the last 42nd TC Annual Session in
Singapore, first activities of the UFRM project should be the survey to China, Japan and Republic of Korea for collecting the good practices on UFRM.
• According to the discussion at the TC Task Force meeting held in Bangkok on 19-20 July 2010, a draft inventory of good practices in the urban flood risk management collected from the selected pilot cites will be prepared by China as the first activity of next steps of the project.
• Before this IWS at Macau, the questionnaires from the three selected cities, i.e., Ansung City (Republic of Korea), Shanghai(China) and Yokohoma City(Japan), were collected.
Outline of cities
Shanghai
Yokohama
Ansung City
Position, area and population: Yangtze River Delta front, covers an area of 6340.5 km2 ,population of over 16 million
1
Climate: sub-tropical climate, mild and humid with four distinct seasons. flood season from May to September.
2
Rivers: area of rivers and lakes is 642.7 km2
Main rivers are Huangpu river and its tributaries3
Topography: flat and low plain, average altitude is about 4 meters. 4
Districts: 18 districts and 1 county, 109 small towns and 3 villages, 101 street offices, 3579 residents committees, etc.
5
Main tasks for flood management: typhoon, rainstorm, high tide and flood
6
Development of city: population, land use7
Shanghai, China
Land use and population
Recent floods in Shanghai “01.8”continuous heavy rain
Rainfall is concentrated and has big intensity. 1-h precipitation exceeds 105 mm, exceeds the drainage standard (30-year return) in urban area
Recent floods in Shanghai “Maisha”(No. 0509) Typhoon
Features: heavy wind force, ) heavy rainfall (exceeded 200.0mm in many stations), highest tide in Huangpu River exceeded the warning level, the highest water stage in rivers exceeded historical records widely on the Huangpu River .
Yokohama, Japan
Position: be located approximately 30 km to the southwest of the Japanese capital city, Tokyo. (with an area of 437km2)
1
Rivers: in the Tsurumi river basinThe Tsurumi River is one of the class A rivers in Japan, whose river basin area is 235 km2 . It flows for 42.5 km through Machida City, Yokohama City, and Kawasaki City
3
Social and economy: where 3.68 million people or 1.58 million households live. The GDP of the city is about 13 trillion yen. Its main industries are manufacturing such as electric machinery and transport machinery and service. The Yokohama port is a top-class in Japan terms of trade volume.
2
Development of city: population, land use4
Population Land use
Yokohama, Japan
Recent floods in Yokohama city
September 1982 Typhoon Judy Inundation above floor level: 910Inundation below floor level: 1,800
July 1998 Surface water flooding by frontal-type heavy rainfall
October 2004Surface water flooding by Typhoon Ma-on
July 2008 Torrential rainfall over 77mm/h, 30 houses were flooded
August 2008Torrential rainfall
Ansung Stream, Korea
Position: The Ansung stream basin, the middle west of Korea, is located in 126°50 127°00 east longitude 36°50 37°20 ′∼ ′ ′∼ ′north latitude.
1
Ansung Stream, Korea
Rivers: The Ansung Stream, of which the basin area is 1,655km2 and the stream length is 70.0km.
3
Topography: flat land except upstream. 2
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하천차수
(i) Channel system (ii) Land cover map (iii) Soil map
Land use and population
(i) 1990 (ii) 1995 (iii) 2000 (iv) 2005
(i) 1990 -1995 (ii) 1995 -2000 (iii) 2000 -2005 (iv) 1990 -2005Change of population in GyeongGi-Do, Korea.
Time-series data of land use of urbanization in GyeongGi-Do , Korea
Recent floods in Ansung city
August 1972 Concentrated Heavy rainfall 20 ha of landslides occurred consisting of 632 slides within the 20 750ha of forest land
July 1991 Heavy rainfall about 250ha of landslides occurred in the Ansung-gun district over an area of 553km2 and 200 ha of landslides occurred in the Yongin-gun district over an area of 592km2 area
July 2006 Heavy rain of 271mm made some levee breaches 130 houses were inundated and 240 residents evacuated
Good practices in urban flood management
a To establish the comprehensive urban flood management strategy
To highlight the land use planning.b
To enhance meteor-hydrological monitoring, forecasting and warning to provide timely, accurate and all-sided information support to the urban flood management.
c
To build up various dissemination ways of flood warning information to individual residents
e
To apply flood hazard/risk map widely as an important technique of urban flood preparedness.
d
To emphasize on the function of retarding basins and discharge ponds in the urban flood management
f
Urban flood management strategy -Shanghai
“FIVE SYSTEMS”
flood control works system flood control works system
organizing and commanding system organizing and commanding system
information security system information security system
rescue system rescue system
Good practices in urban flood management
early warning and pre-arranged planning system early warning and pre-arranged planning system
Good practices in urban flood management
In working principle, insist safety first, defense as the main work, often prepared not relax, utmost rescue, try to grasp the initiative of prevent flood and typhoon
In working principle, insist safety first, defense as the main work, often prepared not relax, utmost rescue, try to grasp the initiative of prevent flood and typhoon
In working concept, insist people oriented, to place ensuring the safety of the lives and properties in the first place, try to achieve no death and less loss.
In working concept, insist people oriented, to place ensuring the safety of the lives and properties in the first place, try to achieve no death and less loss.
In working mechanism, insist various levels of flood control responsibility system whose core is responsibility system of administrative chiefs,
In working mechanism, insist various levels of flood control responsibility system whose core is responsibility system of administrative chiefs,
In working measures, insist considering both construction and management and treating management as the key. Continuous tamp the material foundation and management foundation
In working measures, insist considering both construction and management and treating management as the key. Continuous tamp the material foundation and management foundation
In emergency rescue, insist the people and the army joint together In emergency rescue, insist the people and the army joint together
“FIVE INSIST”
Urban flood management strategy -Shanghai
2 Good practices in urban flood management
To highlight the land use planning.b
Shanghai--The scheme of planning control line (Blue Line)
For the construction projects in river managing scope, should be examined and verified by Shanghai river management bureau or river administrative department. out of the river management scope usually didn’t consider flood hazard.
Constructions of other infrastructures such as railways and high ways should be designed according to the national standard Flood Control Standard.
2 Good practices in urban flood management
To highlight the land use planning.b
Yokohama city– Acts and ordinances to guiding the land use – “Act on Countermeasures against Flood Damage of Specified
Rivers Running Across Cities” • developers must construct rainwater storage and infiltration
facilities if the area is over 1,000m3 and • owners of discharge ponds over 100m3 are obliged to maintain
their function.– Ordinance to coordinate development by private sectors with
city planning• the city directs developers to construct rainwater runoff control
facilities and maintain open spaces to grow trees. – To designates “urbanization promotion area” and “urbanization
restricted area”
Good practices in urban flood management
To enhance meteor-hydrological monitoring, forecasting and warning to provide timely, accurate and all-sided information support to the urban flood management.
c
MAPLE (McGill Algorithm for Precipitation nowcasting and Lagrangian Extrapolation) method, by NIMR, Korea
Combine the point rainfall data at the gage stations and that of the climate radar to get more accurate forecast of rainfall.
MAPLE and AWS stations and adjustment integration
Grids for the rainfallin Ansung data watershed
area
Good practices in urban flood management
The integrated typhoon and rainfall Monitoring &Detection System of Shanghai
Constituted by 98 auto-weather stations, 120 rain gages, 3 Doppler weather radars and 12 meteorological satellite receiving systems
Forecasting System in Shanghai
• STI-WARR for 1-12h, STI-WARMS for 3 days and STI-EnWARMS for 5 days, developed by Shanghai Typhoon Institute (STI) – New numerical techniques for improving forecasting : digital filter,
cloud analysis, ADAS-3DVAR and hourly assimilation cycle et. al. – And for TC forecasting : BDA (bogus data assimilation) technique,
satellite data assimilation, GRAPES_TCM TC model, relocation cycle, ensemble and air-land-sea coupled model.
• A Storm Surge Early Warning Subsystem, developed by STI.
Good practices in urban flood management
Good practices in urban flood management
To apply flood hazard/risk map widely as an important technique of urban flood preparedness.
d
Different Flood hazard/risk maps were used in all the three pilot cities, which contributes to guidelines for land use planning and strengthening the capacity buildings for special regions.
Flood risk map in Shanghai Flood risk map in city centre)
Flood hazard map (SMB)
Possibility for flooding damages in Ansung Stream basin
• Korea– Flood-warning or flood-alarm will be announced to the public
through the mass media (broadcast, newspaper, etc) and related agencies so that citizens can prepare and evacuate against flood.
• Japan– Flood advisories, warnings and forecasts are transmitted to
municipalities via prefecture. – provided by , internet, CATV, sirens. – directly to (registered) residents (e-mail , mobile phones)– Kohoku ward provide information by internet fax to underground
facilities
Good practices in urban flood management
To build up various dissemination ways of flood warning information to individual residents
e
• China– The spokesman system. – SMB provide special services through multi agency cooperation – Communications departments such as radio, television and the
official government website – Transportation operators such as airports, railways stations,
harbors, tourist attractions and traffic control provide resources to facilitate the distribution of early warning information.
– The Public-level Dissemination Platform• Community warning light system :electronic screens, billboard TV
screens, and electronic road signs.
Good practices in urban flood management
To build up various dissemination ways of flood warning information to individual residents
e
Inundation risk analysis Storm surge disaster risk analysis
Dyke breach risk analysis
Early warning message
Good practices in urban flood management
To emphasize on the function of retarding basins and discharge ponds in the urban flood management
f
Yokohama City– According to “Act on Countermeasures against Flood Damage of
Specified Rivers Running Across Cities”, developers must construct rainwater storage and infiltration facilities if the area is over 1,000m3 and owners of discharge ponds over 100m3 are obliged to maintain their function.
– 4,170 (total volume is 2.96 million m3, as of the end of 2008) have been constructed by private sectors who had developed certain areas in the basin, with subsidy.
– Yokohama city has constructed 1,956 (about 1.65 million m3) regulation ponds and 1,662 infiltration trenches.
ThanksThanks谢谢谢谢 !!