| Summary: | 碩士 === 國立中央大學 === 應用地質研究所 === 91 === Grey Relational Analysis for the Synthetic Evaluation of Reservoir Water Quality
: Case Studies of Feitsui and Shihmen Reservoir
Shao-Wei Chiu
ABSTRACT
Feitsui and Shihmen Reservoir are the most important water resource for the metropolitan Taipei city as well as northern Taiwan. Although water quality assessment is such an critical issue, a reliable synthetic evaluation index concerning eutrophic reservoir and water pollution are still lacking at present. The purpose of this study is to establish a new evaluation method for the eutrophic and water pollution conditions of reservoir. Grey relational analysis was processed by using Feitsui and Shihmen Reservoir as case studies, so as to perform a multi-indices synthetic evaluation.
For the eutrophic condition of reservoir, Grey relational analysis and Analytic Hierarchy Process (AHP) were employed to calculate the weighting of each parameter(Chl-a, SD and TP), so as to perform a synthetic evaluation with multi-indices. The analytic results indicate that 1) a simple, clear classification and evaluation model for the eutrophic reservoir can be successfully established. 2) Grey relational analysis with Analytic Hierarchy Process (AHP) of weighting in classification exhibits a reasonable and appropriate classification. Furthermore, the eutrophic condition of reservoir can thus be evaluated in a quantitative way. 3) The water quality of both Feitsui Reservoir and Shihmen Reservoir were turning mostly to mesotrophic or eutrophic after typhoon; On the other hand, their eutrophic condition did not exhibit any significant variation in the drought season of 2002. 4) Among the monthly and annual data evaluated, most of the water quality of Feitsui Reservoir were concluded as oligo- to mesotrophic, except for the months of June, July, October, November and December; in addition to the years of 1992, 1996, 1998, 1999 and 2000, which were classified as eutrophic in AGRA value. This conclusion is furthered confirmed by field observaton.
As for the water pollution of reservoir, Grey relational analysis and NCKU WQI8 method were further combined to perform a synthetic evaluation with multi-indices. The analytic results indicate that 1)The water quality of both Feitsui Reservoir and Shihmen Reservoir turned to worse in the drought season of 2002. 2) Grey relational analysis basing on NCKU WQI8 of weighting in classification exhibits a reasonable and appropriate evaluation for water pollution. Again, the water pollution condition of reservoir can thus be evaluated in a quantitative way. 3) Among the annual data evaluated, the water quality of Feitsui Reservoir is getting worse and Shihmen Reservoir is getting better in recent years. This conclusion needs to be further confirmed by future studies.
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