|摘要: ||各國使用不同水質營養狀態指標管理湖泊、水庫水質，台灣環保署應用卡爾森(Carlson trophic State index TSI, CTSI )，CTSI水質參數包含葉綠素-a(Chl-a)、透明度(SD)與總磷(TP)。本研究使用石門水庫及翡翠水庫1993-2012年之水質監測資料計66組，研究目的: (1) 比較各營養狀態指標之差異、(2)探討石門水庫及翡翠水庫之優養化限制營養源、(3)評估各營養狀態指標判定優養化之差異。此外，營養狀態指標包含CTSI、OECD綜合指標、加拿大總磷單一參數指標、中國大陸綜合營養狀態指數法(TLI)、及美國勘薩斯州葉綠素a(TSI(chl-a))、及美國佛羅里達州TSI(TSI)。|
研究結果顯示各水質營養狀態依參數項目、指標函數，其分級為3-6類，CTSI分級3類，易判定水質為優養化。石門水庫與翡翠水庫之TN/TP平均比值分別為13.67與21.88，故其優養化限制營養鹽分別為TN及TP與TP。主成分分析法選定石門水庫水質優養化主要影響因子為TN、葉綠素a與TP，翡翠水庫則為SS、TP與TN。CTSI水質參數相關性顯示總磷與CTSI相關性為優於葉綠素a與CTSI相關性。以CTSI判定優養化比例為9-14%，OECD與TSI(chl-a)則分別為1-2%與0-12%；OECD之優養化比例很低，乃因其分類為5類，判定優養化之營養狀態值為54.2大於CTSI之50所致。且。此外，由於翡翠水庫葉綠素a濃度低，其範圍為0.15-7.05 μg/ L (平均值2.42 μg/ L)，致使以TSI(chl-a)判定優養化比例為0。綜合結果，因CTSI分級只分為3類，造成判定為優養化比例高，建議台灣環保署檢討其它營養狀態指標應用於水庫水質管理之適宜性。
Various trophic state indices are used to manage water quality in lakes and reservoirs in countries.The Taiwan EPA uses the Carlson trophic State index (CTSI) and its water quality parameter includes chlorophyll-a (Chl-a)、Secchi depth transparency (SD) and total phosphorus. The water quality data of Shimen reservoir and Feitsui reservoirs, which was monitored during 1993 to 2012, was collected from the Taiwan EPA. The purposes of this research were: (1) to review the trophic classification among trophic state indices, (2) to evaluate limiting nutrient of eutrophication in the Shimen reservoir and Feitsui reservoir, (3) to assess the eturophication ratio by various trophic state indices. Moreover, the trophic state indices included CTSI, OECD comprehensive index (OECD), the Canadian single parameter index on total phosphorus (TP), China trophic level index (TLI), Florida trophic state index (TSI), and Kansas trophic state index on Chl-a (TSI(Chl-a)).
The result shows that based on water quality parameters and Sub-index function, trophic status of water quality can be grouped into 3-6 classifications. It was easier to be considered as eutrophic status by CTSI because CTSI grouped trophic status only into 3 classifications. The average of total N/P ratio of Shimen reservoir and Feitsui reservoir was 13.67 and 21.88. And, limiting nutrient was TN and TP for Shimen reservoir, whereas it was only TP for Feitsui reservoir. The result from the principal components analysis indicated the main parameters causing eutophication for Shimen reservoir and Feitsui reservoir were TN, Chl-a, TP, and SS, TP, TN, respectively. The correlation between CTSI and TP was better than that between CTSI and Chl-a. The ratio of eutrophic status was 9-14% by CTSI, and there were 1-2% and 0-12%, respectively, for OECD and TSI(Chl-a). It indicated the very lower ratio of eutrophic status by OECD because OECD grouped trophic status into 5 classifications, and the trophic status value for grouping eutrophic by OECD and CTSI was 54.2 and 50. Furthermore, due to being low concentration of Chl-a ranged 0.15-7.05μg/ L (average = 2.42 μg/ L) of Feitsui reservoir, the ratio of eutrophic status was 0%. Therefore, it could conclude that it was easier to be considered as eutrophic status by CTSI because CTSI grouped trophic status only into 3 classifications. It suggests that Taiwan EPA review the suitability of other trophic state indices to evaluate the trophic status of reservoir water quality.