A study on the forest environment changes by long term extreme drought and headwater watersheds management measures for water conservation -A case study of Matsuyama city-

这项研究的目的是为了流域管理措施，以确保适当的和自然平衡的生态系统在该地区。研究结果如下：1.利用四国6个坝集区1994、1995年水文资料，分析了特旱年的流量历时特性及其影响，并对流量历时稳定比进行了推断。将1995年卫星遥感数据的NDVI值与正常年份（1989年）和极端干旱年份（1994年）的NDVI值进行了比较。干旱年份，山脊的NDVI值较低，而山谷的NDVI值并没有变低。干旱年份的影响是在森林植被完全恢复或未恢复的单位坡的次年进行的。由单位坡度得到的差异对森林的经营管理有一定的指导意义.在濑户内海江田岛的3个流域（2个火灾流域和1个非火灾流域）上，用张力计观测了土壤含水量的变化。在干旱年份，无火害流域的流量持续时间稳定性较好。根据土壤水分观测结果，假设在未发生火灾的流域，土壤水分大量渗入深层土壤或基岩。通过对多摩川水库上游流域（东京）森林植被变化的流量历时数据分析，发现了正常水深的增加与砍伐树木的减少以及森林植被的增加与森林植被损失量的增加之间的关系.对爱媛县森林水源保护调整方法进行了方案设计。

The purpose of this research is aimed at watershed management measures that would ensure proper and naturally-balanced ecosystem in the region. The results of this research were as follows :1. In 1994 and 1995 hydrologic data of 6 dam watersheds of Shikoku, behavior of discharge duration analysis and its effects in extreme drought year and stability ratio of discharge duration were used for inference. NDVI values from 1995 satellite data were compared with that of normal year (1989) and extreme drought year (1994). In the ridge, NDVI values were low for in the drought year, but did not become low in the valley. The effects in drouht year were taken the following year from a unit slope where forest vegetation had fully recovered or not. This disparity obtained from this unit slope are useful for the management of forest.2. Observations on the changes of soil moisture content were taken in the tentionmeters on 3 watersheds (2 fire dameged and 1 no fire dameged watersheds) at Etajima island in Seto Inland Sea. The discharge duration stablitiy was good for no fire damaged watershed in drought year. As the results of the soil moisture observations, the large water amount of infiltration into deep soil layrs or bed rock was assumed in the watershed without fire damaged.3. From the analysis of discharge duration data on Tamagawa dam headwater watershed (Tokyo) with changes in forest vegetation, a relationship was discovered in the increase of ordinary water depth with the decrease of cuting down trees and the volume of discarge loss increases with the increase of forest vegetation.4. The scheme in Ehime prefecture was made for forest headwater conservation adjustment method.