This year, we have learned a lot of lessons from the frequent disasters
caused by abnormal weather, not only in Japan but also all over the
Recent attempts in the world to prevent disasters seem to adopt flexible measures in tune with the power of nature instead of trying to conquer it.
In other words, we should stop building a "rigid infrastructure" to prevent natural disasters; instead, we should try to build a flexible structure for reducing natural disasters as much as possible in order to get rid of the above-mentioned vicious circle.
One is reminded of the experience of disaster-reducing effects in "Minuma Tanbo" in Saitama Prefecture.
When the Shiba Kawa of Saitama flooded at the time of Kanogawa-Typhoon in September 1958, it is said that the flooding in Kawaguchi and Toda cities remained relatively light because Minuma Tanbo pooled and held about 10 million tons of water for several days.
As a result, the 'natural' flood plain of Minuma Tanbo was well recognized and the "three principles of Minuma" (which did not allow the land to convert into a farmland) was formulated.
When we shift our attitude from preventing disasters to reducing them, we notice that there are various accompanying benefits resulting from such a shift of our attitude.
With the conventional way of river improvement, there is open space remaining outside of the banks after the improvement. On the contrary, with a flexible disaster-reducing infrastructure, we could have open space inside the banks.
The space cannot be used for production activities or as living space.
Naturally it will have an enhanced value as an ecosystem space.
Or it could be used as a kind of communal or hobby farmland for the public affecting no one's livelihood.
Realizing abundant green space around cities at river deltas
In the past, most places at river deltas in Japan are narrowed with river improvement works. Open spaces outside of the banks thus created by the river improvement could be used to enlarge the city area for housing or any other urban development.
If we could materialize river delta cities abundant with green space following our above-mentioned "paradigm shift", this might be a revolutionary breakthrough in future city planning.
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