Governor of Kuwashima, Kumamoto Prefecture Change of Flood Control Measures November 19, 12:35 p.m. calling on the government to build a new dam
With a view to flood control measures in the Kuma River basin in Kumamoto Prefecture, which was flooded by heavy rains in July, the governor of Kumamoto Prefecture expressed his intention to change the “water control measures that do not depend on dams” that he has led himself, and to ask the government to build a new dam that is environmentally friendly.
In the morning of July 19, The governor of Kumamoto Prefecture attended a meeting of all members of the prefectural assembly to explain his thoughts on the plan to build a dam in the Kawabe River and the flood control measures for the Kuma River basin, where 65 people died in the prefecture due to the heavy rain disaster in July.
In this statement, Governor Kuwashima stated that he would seek a new “flow-type” dam that would protect the lives of residents and even protect the clear stream, which is a local treasure, and expressed his intention to change the “water control measures that do not depend on dams” that he has led himself, and to ask the government to build a new dam.
The “flow water-type” dam that Governor Kuwashima wants is a structure that flows without water except in the case of heavy rain, and is said to have less impact on the environment than conventional “storage type” dams.
Regarding flood control measures in the Kuma River basin, last month, the government indicated that the flood range would have been reduced by 60% if the Kawabegawa Dam, which Governor Kuwashima had announced 12 years ago, had been built, and there were a number of opinions calling for the dam to be built mainly by the mayors of municipalities in the basin.
Governor Tsujishima tossed the prefectural assembly and said, “The people’s will to protect both life and the environment is the biggest reason for the decision.”
Watershed Damage and National Verification Results
Due to the flooding of the Kuma River caused by the record heavy rain on July 4, more than 6000 buildings, including houses, were found in the watershed.
The inundation amounted to 1020 hectares, which is equivalent to about 220 Tokyo Domes, of which at least 224 hectares, reached a depth of 3 meters, equivalent to the second floor or more of the building.
Of the 65 people who died in Kumamoto Prefecture, the majority were caused by flooding of the Kuma River, and about 80% of the deaths were caused by “drowning” or “suspected drowning.”
In response to this, the government simulated the flood control effect when the Kawabegawa Dam, where the prefecture had withdrawn the plan, had been built, and showed the results at the verification committee meeting with the prefecture and watershed municipalities.
As a result, it is estimated that the Kawabegawa Dam would have reduced the flood area around Hitoyoshi City by approximately 60% due to this heavy rain, and reduced the depth of inundation by 90% to areas that reached a depth of more than 3 meters.
On the other hand, we concluded that the Kawabegawa Dam could not have prevented all damage.
What is a “flow-water-type” dam expressed by the governor?
Unlike “multipurpose dams”, which stop the flow of water in order to maintain water volume for purposes such as water use and power generation, “flowing dams” are structures that flow directly without water except in the event of heavy rain.
It is said that the load on the environment is relatively small because it is possible to maintain the flow of water and sediment from the upper to the lower stages.
Behind the rise of this “flowing water-type” dam were persistent concerns about the deterioration of the clear stream environment, which has also become a tourism resource supporting industries in the basin.
The ryokan association in Hitoyoshi City has taken an opposition to the construction of the dam, as it “leads to the decline of Nariwai.”
In consideration of these voices, Governor Kuwashima has been adjusting the “flow-type” dam around “pursuing measures to maximize the safety of flood control and minimize the impact on the environment.”
On the other hand, evaluations of “flow-water-type” dams are divided among experts.
At a hearing of several experts by Governor Tsujishima, some people called for a cautious response, as “the impact on the environment is inevitable even in a water-flow dam.”
“The will of the people is moving greatly” Governor’s “change of attitude” How did it happen?
In response to the heavy rain disaster, The Governor of Kumamoto Prefecture said that he “take it seriously as a politician” and began to study the flood control measures for the Kuma River in the future with the government and municipalities in the basin.
In this situation, when the flood control effect when the Kawabegawa Dam was built from the country is shown, “Dam is also one of the options”, and since the withdrawal of the blank paper of the dam plan, it will change its stance that it has been “pursuing flood control that does not follow the dam”.
In response, the mayors of the watersheds also throded the implementation of drastic flood control measures centered on dam construction.
In thinking about the direction of flood control measures, Governor Kuwashima used the balance between “water control safety” to protect the life property of watersheds and “environmental protection” to protect the nature of the clear stream and Kawabe River.
In order to “measure the will of the people after the heavy rain disaster,” we set up 30 meetings for residents of the Kuma River basin and various organizations such as tourism, and heard opinions from a total of about 500 people.
In this, while there were calls for the construction of dams, there were also persistent objections, with environmental impacts in mind.
Do you want to build a dam or see it off?
When asked by the press about the direction, Governor Kuwashima avoided saying, “We will work to achieve both the safety and security of the watershed and the protection of the environment,” but also said that “the will of the people is moving significantly compared to the time when the dam plan was withdrawn,” and he looked into his heart’s inclination to build the dam.
Victims of Hitoyoshi City: “The important thing is to build a dam by all means life property”
As for the construction of the dam, some residents affected by the heavy rain in July are in favor of the dam construction because they do not want to suffer the same damage any more.
In Hitoyoshi City, the center was submerged by flooding of the Kuma River, and more than 3,000 houses were completely destroyed and flooded on the floor, and 20 people were killed.
This is the third time that Norio Tsubogami, 80, who lives along the river, was hit by a flood, and after the flood in 1965, the house was raised and rebuilt, but in this heavy rain, water came to a height of more than 3 meters and flooded the second floor. He escaped to the veranda on the second floor and was rescued more than eight hours later.
Mr. Tsubogami said, “I thought it was dangerous, but I lost my life. I don’t know what would have happened if my body hadn’t been cold. When I see a broken house, I cry.”
My home will be demolished, but I’m thinking of renovating my parents’ house, which was relatively less damaged, without rebuilding it because of the high cost. However, because of the flat, we are concerned that we will be flooded again next year and there will be flood damage.
At the neighborhood association where Mr. Tsubogami lives, along with the neighborhood association nearby, a request for the construction of the dam was submitted to the prefecture last month, and Mr. Tsubogami also signed it.
Mr. Tsubogami said, “There may be a linear precipitation zone again, and you will not be able to live with peace of mind as it is now. I can understand why people who oppose dams want to protect the clear Kuma River, but what is more important is the property of life, so I would like you to build a dam.”
Men affected by the disaster “decision to protect both life property and the environment”
As for Governor Tsujishima’s decision to build a new dam, Norio Tsubogami, 80, who now rents an apartment and lives with his wife because his home in Hitoyoshi City was flooded to the floor on the second floor due to heavy rain in July, said, “I was relieved by the decision to protect both the property of life and the natural environment. It’s an attached place I’s lived in for more than 70 years, so I want to go back quickly. I don’t know if both of us will be able to stay healthy until the dam is built, but we hope that the smiles of our children and grandchildren will return, and we would like to cooperate with those who opposed the construction of the dam and watch what happens in the future.”
Against the construction, fisheries officials in Sagar village
The Kawabe River is known throughout the country as a clear stream that can take high-quality ayu. Some fisheries officials have objected to the construction of the dam in an order to protect the clear stream.
Yuichi Tasoe, 50, a river fisherman in Sagara village where the dam will be built, became a river fisherman 12 years ago after Governor Tsujishima announced that he would withdraw the dam plan.
Mr. Taso said, “When I came to the Hitoyoshi-Kuma region on a transfer, I wanted to work in the clear stream, so I became a river fisherman because I thought that the clear stream would be protected because Governor Kuwashima withdrew the dam plan.”
However, since the heavy rain in July this year, the environment of the river has changed, and the day when the ayu cannot be caught has continued. In addition, I worry that the environment will deteriorate further because the dam plan has been raised again.
Worried about whether he would be able to continue living as a river fisherman, Mr. Ta deputy directly told the governor last month that he was opposed to the construction of the dam by attending a meeting to listen to residents’ opinions on flood control measures in an effort to protect the clear stream.
Mr. Taso said, “If the sedoization of dam lakes occurs, water quality will be poor, and the impact on river ecosystems and the deterioration of the quality of ayu and yamame are inevitable. First of all, I want you to remove the sediment deposited in the river and strengthen the levee.”
Hitoyoshi City ryokan owner “Conclusion too early and sorry more discussion”
Kenjiro Horio, 63, who has run Hitoyoshi Ryokan, a long-established inn in Hitoyoshi City, Kumamoto Prefecture, which has been around for three generations since 1934, said of Governor Tsujishima’s decision to build a new dam, “It is too early to draw a conclusion. I wanted more discussion.”
Mr. Horio was worried that the construction of the dam would destroy the environment of the Kawabe River, a clear stream where natural ayu etc. are often caught, and that the Kawabe River as a tourist resource would be lost.
Horio-san’s inn has been flooded by heavy rains in 13 of the 21 rooms, and there is still no prospect of recovery more than four months after the heavy rain.