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【JWF News Vol. 181】4th Asia-Pacific Water Summit “1 Year to Go Event”
20 November 2019
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◇ Contents ◇
・Foreword The principle of flood control: to lower water levels by 10 centimeters, or even 1 centimeter
・Report from the Japan Water Forum
– 4th Asia-Pacific Water Summit “1 Year to Go Event”
– Report on the 7th Asia-Pacific Urban Forum (APUF-7)
– The participation in the Budapest Water Summit 2019
・Bulletin Board
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・Foreword The principle of flood control: to lower water levels by 10 centimeters, or even 1 centimeter
By Kotaro Takemura, Chair of Japan Water Forum
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On 12th October 2019, super typhoon Hagibis swept through the Kanto and southern Tohoku regions. In more than 70 locations on more than 50 rivers, levees were breached, causing unprecedented disasters in the Tokyo metropolitan area and Tohoku region. Various opinions were exchanged on the radio, TV, and internet by those trying to understand these serious disasters. What is flood control? What is the core principle of flood control? I thought it necessary to work out my standpoint based on these questions.
The Principle of Flood Control
Flooding is a natural phenomenon. A natural phenomenon doesn’t occur in methodical way. Sometimes it belies our predictions. When we face nature, we are likely to be tossed about by its capriciousness. When this happens, we tend to lose sight of the basis or principles we should rely upon.
In tackling unpredictable and furious flooding, we have to stick to a firm principle. This principle must be concise and clear: to lower floodwater levels. What we must do is lower floodwater levels even by 1 or 2 centimeters if we can’t achieve 10 centimeters. This is the principle of flood control. When a flood comes, it is an absolute requirement to lower the water level in order not to place an extra burden on levees.
The main principle of flood control is simple and consistent. It does, however, encompass a wide range of methods. Besides, difficulties are inherent in each of these flood control methods. Each has its strong and weak points. There is no infallible measure for flood control. What we can do is choose the best method for each river.
A Wide Range of Flood Control Measures
Broadly speaking, there are various methods of flood control. The most rudimentary one is to deliberately break levees and cause flooding in a particular area of the upstream. If this is accomplished, water levels will fall in the downstream. It is a very effective flood control method and has been widely used around the world since ancient times. It has been heavily relied upon in Japan.
Changing the course of a river or to use a discharge channel is a method called river switching or spillway. This is a way to guide floodwater into another area. By lowering river water levels, the areas along the river can be protected. Major cities like Tokyo and Osaka are protected in this way.
There is a way to widen a river so that water level lower.
Widening a river is effective in both lowering the water levels and draining upstream areas.
Another method is to lower the water levels by dredging a riverbed.
There is also a method of lowering water levels by temporarily storing water in dams and reservoirs. During typhoon Hagibis, dams and retarding reservoirs proved very useful in protecting downstream areas by storing floodwater.
Flood Control Team on Large Rivers
The main principle of flood control is to lower floodwater levels. Though there are various ways of doing this, it is impossible to protect areas along a large river, say, the Tone River, which runs through the Tokyo metropolitan area, using only one method.
A variety of methods are required: enhancing river banks constructed in the Edo period, dredging riverbeds, constructing reservoirs and dams, heightening existing dams and reviewing operations of facilities built by our predecessors, in response to increasingly extreme weather events.
Approaches for effectively combining multiple methods and facilities are needed to protect the Tokyo metropolitan area. This is the only way to protect the area: uniting the wisdom of the Edo period with up-to-date knowledge of the 21st century.
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・Report from the Japan Water Forum
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– 4th Asia-Pacific Water Summit “1 Year to Go Event”
On October 19th in Kumamoto, the 4th APWS Kumamoto City Steering Committee and the Japan Water Forum jointly hosted a kickoff event, the first in a series of relay symposiums in anticipation of the 4th APWS, to be held on 19th and 20th October, 2020.
On behalf of the hosts of the 4th APWS, Mr. Kazufumi Onishi, Mayor of Kumamoto, and Dr. Kotaro Takemura, Chair of the Japan Water Forum, which serves as secretariat of the APWF, attended the event and joined in on discussions on the objectives of the 4th APWS and what we expect from the citizens of Kumamoto.
▼Please visit the following website for details▼
https://www.waterforum.jp/all/policy_recommendations/apws/2019/1119/?p=12476tag=en,rep_en
(Reported by Chief Manager, Sae Ishihara)
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– Report on the 7th Asia-Pacific Urban Forum (APUF-7)
The Seventh Asia-Pacific Urban Forum (APUF-7) took place in Penang, Malaysia, from October 15 to 17.
APUF-7 was co-hosted by the United Nations Economic and Social Commission for Asia and the Pacific (UN-ESCAP), the United Nations Human Settlements Programme (UN-Habitat), Urbanice Malaysia, and the Government of Malaysia. It was aimed at achieving a sustainable future for cities in the Asia-Pacific region by mobilizing all stakeholders across the region. It is a platform for encouraging discussion on innovative solutions, identifying common actions and purposes, and strengthening effective partnerships.
Mr. Kazufumi Onishi, mayor of the City of Kumamoto and vice chair of the Joint Executive Committee for the 4th Asia-Pacific Water Summit (APWS), attended the APUF-7, and called for participation in the coming 4th APWS at sessions entitled Leaders Dialogue and Declare Your Actions.
▼Please visit the following website for details▼
https://www.waterforum.jp/all/policy_recommendations/apws/2019/1119/?p=12397tag=en,rep_en
(Reported by Manager, Natsuko Uemura)
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– The participation in the Budapest Water Summit 2019
The Budapest Water Summit (BWS) 2019 was held in 15th-17th October 2019 by the Government of Hungary, under the patronage of the President of Hungary, János Áder, President of Hungary. Approximately 2500 participants from 118 countries, including H. E. Mr. Samdech Hun Sen, Prime Minister of Cambodia and H.E. Mr. Gajendra Singh Shekhawat, Minister in Ministry of Jal Shakti, India.
Under the BWS 2019 theme, “Preventing Water Crises,” the high-level government and international organizations’ leaders delivered their keynote statement. In addition, the following ten sessions were organized. Each speaker and panelist discussed how to prevent emerging water crises, how to manage crises where they cannot be prevented, identifying relevant gaps in knowledge, governance, technology, finance, regulations, and institutions. They also exchanged opinions with the participants by introducing their cases, lessons and experiences.
▼Please visit the following website for details▼
https://www.waterforum.jp/all/policy_recommendations/apws/2019/1120/?p=12525tag=en,rep_en
(Reported by Manager, Yumiko Asayama)
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・Bulletin Board
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【H20 Saudi Arabia Conference】
Organizer: Eyes of Cities
Date: 20-21 November 2019
Place: Saudi Arabia (Riyadh)
https://bit.ly/2m4Xa1z
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JWF News Vol. 181 / 20 November 2019
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