摘 要 國內過去對於水體水質優養化問題所作之研究結果分歧，在研判優養化程度上多仍延用國外之資料，但國內外環境不盡相同，國外導出之結論並不完全適用於國內。因此，為瞭解水庫及湖泊水體水質優養化的情形並俾利採取合適的處理措施，有必要針對台灣地區提出一套水庫水體水質優養化評估指標。 本研究就目前之優養化指標，選取單一性與綜合性優養指數進行比較與探討，並依水庫分佈位置選擇北、中、南各3座水庫，以多變量統計分析方法，進行主成份分析與因子分析。 本研究初步獲得九座水庫優養化指標(Nine Eutrophication Index, NEI)＝(1.9152*Factor1) + (-0.0034*Factor2) +(1.5136*Factor3) + (0.2353*Factor4) - 2.508399【貧養：NEI <60；中養：60 NEI 80；優養：NEI>80】；寶山水庫優養化指標(Huang Eutrophication Index, HEI)＝(164.9234*Factor1) + (-7.1514*Factor2) +7.795259/1000【貧養：HEI <15；中養：15 NEI 20；優養：HEI >25】。NEI、HE與卡爾森指標趨勢相近，但數據點較和緩，值得進一步深入探討，以獲得更完善之評估指標。 Abstract The objective of this study is to develop an optimal aquatic eutrophication index for the reservoirs in Taiwan. Traditionally, the eutrophication index was used on the basis of the foreign assessment. However, environmental diversities generally lead to an error eutrophication assessment. In order to establish an optimal index for Taiwan, we collect the data from nine reservoirs on North, Central and South of Taiwan to determine the index. In addition, the samples from Pao-Shan reservoirs are analyzed to further demonstrate the obtained results. Both single and complex parameters are applied to elucidate the eutrophication conditions. The results are reported using a multivariate statistical analysis (Principal Component Analysis and Factor Analysis) based on a single eutrophication index and complex eutrophication index . The eutrophication index for nine reservoirs shows as following: (Nine Eutrophication Index, NEI)＝(1.9152*Factor1) + (-0.0034*Factor2) + (1.5136*Factor3) + (0.2353*Factor4) - 2.508399 {Oligotrophic：NEI <60；Mesotrophic：60 NEI 80；Eutrophic：NEI>80}；Pao-Shan Den (Huang Eutrophication Index, HEI)＝[(164.9234*Factor1)+ (-7.1514*Factor2) +7.795259]/1000 {Oligotrophic： HEI <15; Mesotrophic： 15 HEI 20; Eutrophic ： HEI >25}. NEI and HEI are similar to Carlson trophic state index. However, the less change in the data indicates the obtained result need the more detailed investigation in the further to get the better index.
