In erosion control engineering field, various kinds of new techniques have been developed and briskly put into practical uses. Among these techniques, it is said that non�]structural measures have been in demand lately. These measures contain many kinds of techniques and the terminology �gnon�]structural measures" that are still not clear. Therefore, in this study, various kinds of non�]structural measures which have been developed so far are reviewed, and the present technological development measures are analyzed in relation to social demands. As a result, practical needs on these measures, today and in the future, will be clarified. This paper's distinctive feature is its analysis based on the quantity of patent right registration, while in many preceding papers, major analyses used to be conducted based on the quantity of academic papers. Additionally, the questionnaire survey or the hearing investigation was executed to extract the problem that the erosion and torrent control field had, and it listened to engineer's opinion and manager's opinion at the technology development. From the result of this investigation, it turned out to be felt that the entrepreneurial strategy and the advantage of making to the patent are different.


Key words�Fnon�]structural measures, a development trend, patent right registration, the questionnaire survey