治水事業をめぐる諸問題とこれからの治水の課題と展望

Abstract

1896年の河川法制定以後, 20世紀の治水事業は多くの成果を上げつつも, 連続堤防とダムなどによって洪水を河道内に閉じ込める治水方法を進めたため, 20世紀後半にはさまざまな問題を惹き起してきた。これらの問題への反省が20世紀終盤から始まったが, 河川の現場においては旧態依然の方法で治水事業が進められている。本研究は, 上記の諸問題とそれらに関する背景や反省点を整理, 総合して, 現在の発展段階に相応しい治水方策の方向を提示しようとするものである。

Since the establishment of the River Law in 1896, flood control measures have been carried out with anticipated fruits.On the other hand, serious problems have been occurred. They are the getting worse of fluvial environment by river improvement and dam, the problem in determination methods of design flood and the defect in measures for the flooding that exceeds design flood. We can find the cause in the history of flood control in Japan. Recently, the River Council submitted the reports on comprehensive flood control measures (1977, 2000) and measures for the flooding beyond design flood (1987), and the role of traditional flood control measures have been discussed. A partial amendment of the River Law was made on fluvial environment (1997). In this paper, the flood control measures fitting in the twenty-first century are discussed in accordance with above-mentioned subjects.