In Japan identifies the “blank time period for civil engineering projects” that existed from the 9th century to the 11th century, peaking in the 10th century. The most influential underlying factor for this period is thought to be the collapse of the Ritsuryo state in the 10th century. Another more direct cause was the existence of the ideology of “Bon-do (the onmyodo idea of avoiding digging or moving soil so as not to be cursed by the earth god)” that was widely held among the Heian Aristocrats in the 10th and 11th centuries.
 This study shows that the Bureaucratic system related to civil engineering projects in Japan. However, in central government post has not been established to perform civil engineering project. While local government was installed on a temporary basis when a disaster occurs. This study clear to the “blank time period for civil engineering projects” that existed from the 9th century to the 11th century.

View full abstract

 100 years has passed after Sea Fort No. 2 of Tokyo Bay was constructed in 1907 for military use. The fort suffered damage from Great Kanto Earthquake in 1923, there is a progression of deterioration, damage and collapse of the fort caused by winds and waves of many years. For the reason, measures to preserve the fort are being considered. In this study, we collected information of construction plan, construction techniques and design techniques on the first experience of large-scale sea fort construction in Japan. And, we also verified the information and compiled construction history of the fort. Then, we made discussion that the knowledge is used in present construction techniques.

View full abstract

 The Zenkoji earthquake that occurred in 1847 caused many landslide disasters. Among them, the breaching of the Saigawa River dam that resulted from the collapse of Mt. Iwakura during the earthquake caused particularly immense damage. Although the abundance of historical records relating to the disasters have allowed for vigorous research studies, very few studies have focused on the disaster relating to the breaching of the Susobana River dam. In this study, from the perspective of the research concerning the history of river disasters, we studied the landslide disaster that occurred immediately after the earthquake, and chronologically viewed the series of river disasters that occurred in the interim years until the early years of the Meiji period, as well as the related river restoration activities. From there, the relation between the Zenkoji Earthquake and the repairs made to the Susobana River is set forth. Although the double levee structure on the left bank of the downstream site of the Susobana River suffered severe damage, we learned that it was restored over a period of 20 years through the efforts of area farmers.

View full abstract

 Hadai-Road, an expressway in the length of one thousand kilometers, that connects Harbin and Dalian was planned and prepared in Manchuria. This research aims to clarify the characteristics of the plan contents and planning process of the road, and consider the planning process and contents of the Hadai-Road from a viewpoint of the historical significance of it. As a result, three points were drawn as follows.
1) The circumstances and the contents of planned Hadai-Road from 1938 to 1945 were clarified.
2) Hadai-Road was one of the first expressway that were planned by Japanese engineers before WWII.
3) The planning idea and design concept of Hadai-Road had some similarities to the Autobahn so that the influence of the Autobahn built ahead of Hadai-Road was confirmed.

View full abstract

 This paper is an attempt to describe a historical process that the Japanese Government has been making legal system for Land Readjustment, which is one of the most effective tool of city planning in the modern period. The government selected an administrative method called ‘replotting disposition’ to change land use as Land Consolidation Act in 1899. The method has been developed for urban development and reconstruction for damaged urbanized area. Land Readjustment Act in 1954, Act on Special Measures Supplying Housing in Metropolitan Area in 1975 and Act on Special Measures Reconstruction for Damaged Urban Area in 1995, etc. were enacted to achieve such objects.
 The author could find new knowledge on customary title exchanging, change reputation of an old act for farmland improvement and identify origin of basic legal terminology on Land Readjustment Act in this historical study.

View full abstract

 In the Early Term of Showa era, we find a jurisdictional rivalry between the Ministry of Home Affairs and the Ministry of Agriculture and Forestry concerning the subsidy to the river improvement by prefectures. But from the standpoint of prefectures, both subsidies of two ministries were very useful to put works in practice and to reduce the damage of flood. This paper shows that the influence of the jurisdictional rivalry between two ministries was small for Aichi prefecture, and that Aichi prefecture pushed forward effectively with the improvement of small and medium rivers using also the subsidy for the improvement of agricultural channels.

View full abstract

 The datum levels of elevation and water depth are defined differently. The datum levels changed individually from beginnings of modern surveying and hydrography at Meiji Era. The transition has not been traced enough. This report surveys the history of the datum levels in Japan. Especially, primary historical materials published by the organization of a hydrography are examined. For determining the datum level of water depth at the beginning, Mean Low Water Springs was applied. And then, Nearly Lowest Low Water according to the harmonic analysis was introduced. After new datum level applying, permanent tide stations were equipped. The history of datum level of elevation can be summarized as standardization throughout Japan. Both histories of datum levels are contrasted to detect common and different points.

View full abstract