Studies on the "Satoyama Sabo" which is the synthetic Disaster Preventive Space

“中山”是指围绕大城市的山麓地带，由林区、农田、居住区组成的空间，在这里以Sabo规划的名义进行侵蚀产沙控制工作。“Satoyama Sabo”这个名字并不是现有的概念。和平时期，绿色旅游、游览等。在林区以及木材生产、农田作物生产都在这个空间中进行，当大自然的荒野如风暴、台风、洪水等袭击时，这个空间可以作为防灾空间。因此，在这个概念中，作者对“中山”这个空间的现状进行了调查。在三年的研究中，我们确认了以下结果：1)(以下建设洪流的水稻种植的目的,即使这些是嫌弃,这些可以评为洪流床稳定,2)石适用于水稻生产的平台给我们精彩的scenary日本一个国家也发挥重要辊Satoyama sabo侵蚀产沙量控制控制,3)在plannig侵蚀和泥沙控制计划,评估的收益沉积物是必要的,但由于产沙现象的复杂性，目前还没有确定产沙量的精确方法。作者通过野外调查定性地论证了森林和农田在管理得当的情况下可以适度降低产沙率的可能性。

"Satoyama" is the space composed of forested area, farmland area and residence area at the foot hill zone surrounding a big city, in which the erosion and sediment yield control works should be executed under the name of Sabo planning. The name "Satoyama Sabo" is not the existing concept. In a peace time, green tourism, excursion etc. In the forest area as well as timber production, crop production in the farmland are carried on in this space, wherease in a time when attacked by the wilderness of nature as storms, typhoons floods etc., this space could be functioned as the space of disaster prevention. Thus, in this concept, authors have investigated on the present state of this space "Satoyama". In three years of researches, we have recognized following results ; 1) water intaking constructions in the torrent for the purpose of rice cultivation, even if parts of these are abandonned, these could be appraised as for the torrent bed stabilization, 2) stone works for the terrace of rice production which give us wonderful scenary of a country in Japan also play an important roll for Satoyama sabo for the erosion control and sediment yield control, 3) In plannig erosion and sediment control plan, to evaluate exact yield of sediment is needed, wherease due to the complexity of the phenomena concerning sediment yield, there is no exact method of deciding it. authors have shown qualitatively the possibility according to the field investigation that forest and farmland can reduce the rate of sediment yield fairly in case that they are properly managed.