| Summary: | 碩士 === 國立臺北科技大學 === 土木與防災研究所 === 101 === The change of hydrological environment in a watershed due to land use variation is usually slow and imperceptible. Since there are complicated relationships among water quality, water resource and ecosystem, the change of geographical environment will result in a variation of ecological environment and impacts of water quality. The rivers and the Feitsui reservoir at the Taipei water source district is an important source of water supply in Taipei Area. The control and management of water quality is a primary concern in this area. Therefore, it is an urgent need to establish the knowledge in land uses, water quality and ecology in the watershed.
The objective of the study is to use the landscape ecological metrics to assess land use change and associated impacts on water quality and ecology. The SPOT satellite images of 1995 and 2012 were implemented classification, change detection, and the landscape ecology metrics calculation at eight sampling sites in the district. The results showed that the agricultural area has expanded and partially replaced the area of forest and road at the Pinglin, Hu Liao Tan of Peishih River and Cukeng Dam of Nanshih River. The change was less in Bihu and in the upstream of Tungho River. It can also conclude from the study that when it tends to the downstream location in the special district, the cluster of construction zone, the contiguity of agricultural zone, the meander of road zone and the polymerization of water zone increase, but the fractional of forest zone decrease.
This study performed the correlation analysis for landscape metrics of each area and ecological indices of water quality. The result showed that it could bring out negative influences when large area and long length of edge of construction zone and road exist, which is the results of human activities. The trend was getting worse in agricultural blocks when the quantity of patches increased, the density elevated and there were situation such as perforation and fragmentation. There were positive effects in blocks of grass and forest if they were in large area of blocks and adjacent to each other, because they functioned like the buffer strips. It can see from the study that it is capable of evaluating the landscape distribution and the change of water quality in this area by comparing the spatial and temporal variation of landscape metrics.
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