The “first joint symposium on sound water cycle in Tokyo” which is organized by the Executive Committee for Sound Water Cycle in Tokyo was held at the Faculty of Science and Engineering, Chuo University on December 3, 2014. Dr. Tadashi Yamada, the organizer of the Program for Capacity Building in Global Water-Environmental Engineering (herein after to as the Program) cum professor for the Graduate School of Science and Engineering served as the chairperson of the executive committee on the joint symposium.
The theme of the first symposium was "Tokyo, the city built on water will be created through the activation of the Tamagawa Water Supply System". A total of 200 people participated in the symposium including those concerned with water environment, and people from partner businesses, public agencies and academics related to the Program. From the Program, 11 people contributed to the symposium. Dr. Yamamura, Industry-Academia-Government Collaboration Coordinator of the Program cum assistant professor for the Graduate School of Science and Engineering acted as the Master of the Ceremonies. Prof. Yamada participated as a keynote lecturer as well as a commentator in the panel discussion. An eight-member student team (consisting of Japanese, Chinese, Korean and Vietnamese university students) commonly known as " Sotobori Study Team " in the Program participated in the poster session.
In the keynote lecture, Prof. Yamada suggested that the observation and analysis by " Sotobori Study Team " showed that water pollution of a closed waterway; the Sotobori, consisted of three elements, such as (1) after large-scale rainfall, like a local downpour in recent years, poured into the Sotobori, water of the Sotobori is purified. Mud, so-called sludge accumulated on the riverbed is washed away quickly to Tokyo Bay, and the water quality of the Sotobori is improved, (2) its worst for the water quality of the Sotobori after medium-scale rainfall. Rainfall stirs up sludge and makes activates microorganisms. In consequence, it is difficult for the creatures inhabiting the Sotobori due to lack of dissolved oxygen in the water, and (3) the water of the Sotobori is purified once after dredging of sludge, but situation doesn't continue for a long time due to sludge re-accumulation originating from sewage.
Prof.Yamada mentioned in the keynote lecture that the water pollution of the Sotobori caused by sewage overflow was more serious in the summertime. If we could always introduce fresh water into the Sotobori, water of the Sotobori would be purified. "Sotobori Study Team” elucidated that from their steady observation and analysis. Though Tokyo had originally been a beautiful city which had a sound water cycle, she made a mistake by developing to quickly; to avoid water from her people’s eyes or people’s life with a facility like under drains. Because the Sotobori also had cultural property value, if we can realize the Realization of a water purification in the Sotobori , we would be able to take back one of the world’s famous sound water cycle cities, "Tokyo and give pride to those young engineers who engage in this momentous work.
In addition to the keynote lecture, various reports were given by representatives of Tokyo University of Science, Hosei University, Nihon University and Tokyo University, and local citizens group and organizations. There were suggestions about the sound water cycle project including a water source and water transfer method, as well as reports of recovery of “the sound Water Cycle City, Tokyo ", the local cooperation with the Sotobori revival, the activation of the Tamagawa Water Supply System and the importance of total management of water utilization.
Finally, a panel discussion entitled "Tokyo, the city built on water will be created through the activation of the Tamagawa Water Supply System" was held by representatives and commentators. At the end of discussion, they summarized that it is very important to think about "sound water cycle in Tokyo" with many more stakeholders’ participation, and to promote concrete actions with them.
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