Study on the deterioration of ecological environment in mountainous disaster areas and on the essential conditions for environmental conservation in their reconstruction processes.

1. 本项目旨在调查山区灾区生态环境的恶化情况，以及在山区重建过程中采取环境保护措施的必要条件。调查区域位于；a)大野盆地，福井-教授。b)长野县稻谷大志村（Ohshika-Mura）。1963年3月的特大洪涝灾害后，中国一直在积极进行重建工作。3 .通过航空摄影、官方调查资料和实地考察，绘制了各调查区域不同阶段的地质生态图，并通过文献资料和实地观测，考察了各调查区域环境和社会结构的变化过程。本研究的主要成果如下：(1)在大野流域，由于暴雪后过度抽取融雪水，导致地下水枯竭。但是，由于盆地中水田的灌溉水的渗透，夏季通常会恢复更多的水。然而，最近甚至在夏季也出现了地下水短缺。可以指出，最近几年地下水的持续枯竭至少部分是由于集水区水田灌溉水的入渗减少造成的，在集水区，通过土地改良工程建造了混凝土渠道和固化的田床。为了恢复该地区的最佳地下水供应水平，在德国西部成功实施了一些水资源保护措施，如恢复自然溪流、考虑地质生态因素后的土地利用规划等。(2) 1961年6月暴雨造成的滑坡和泥质洪水严重破坏了位于河谷底部和河谷阶地上的许多居民点。在战争期间，由于山坡和河道的破坏，这一地区的洪水破坏更为严重。值得高度赞赏的是，沿着受损山谷的河道重建工作主要使用天然材料而不是钢铁和混凝土。1961年洪涝灾害后的30多年间，河道沿线逐渐恢复了黑桤木、白桦等原生植被，这种工程方法对流域保护具有地质生态效益。少

1. This project aims at an investigation of deteriorationg ecological environment in mountainous disaster areas and of the essential conditions for environmental conservation measures in their reconstruction processes.2. Survey areas are located in ; a) Ohno-basin, Fukui-Prof., where problems of ground water depletion have very often been broken out recently, and b) Ohshika-Mura, Ina-valley, Nagano-Pref., where active reconstruction works have been going on after the severs flood disasters of 1961.3. In the survey areas, the geo-ecological maps of different stages were produced by means of aerial photographs, official survey materials and field works, and the process of changing environmental and social structures of the respective areas were investigated by the documents and filed observations.4. Main results of this research are as follows ;(1) In Ohno-basin, ground water used to be depleted through excessive pumping up of snow-melting water after heavy snowfall. But, level of ground … More water was usually recovered in summer season, thanks to the infiltration of irrigation water from paddy fields in the basin. Recently, however, ground water shortage occurs even in summer. It coluld be indicated that continuous depletion of ground water in the latest years has benn caused, at least partly, by the decreased infiltration of irrigation water from paddy fields in the catchment areas, where concreted channels and solidified field beds were constructed through the land-melioration works. In order to recover an optimum level of ground water supply in this area, some conservation measures for water supply, such as, restoring natural streams, land use planning after the geoecological considerations, and so on, which are successfully enforced in western Germany.(2) In Ohshika-Mura, many settlements, located in valley bottom and on talus or river terrace, were seriously damaged by land slide and muddy flood folw caused by the torrential rain of June 1961. Flood damages in this area were worsend by the devastation of mountain slopes and river channels during the war time. It can be highly appreciated, that the reconstruction works of the river channels along the damaged valleys were carried out mainly with natural materials instead of steel and concrete. The engineering methods of this type can be appraised as geoecologically effective for the river basin conservation, in view of the fact that the native kinds of vegetation, such as black alder, white birch, etc., have been gradually recovered along the stream channels during the thirty years after the flood damage of 1961. Less