- 期刊
德基水庫水質優養等級之研究
A Study on the Eutrophication Status of Tecchi Reservoir
摘要
德基水庫位於水力資源豐富之大甲溪上游，由於受到集水區農業污染之影響，水質日益惡化，為瞭解水庫水質優養等級變化，以水庫上下游具代表性之6、18、28、39等斷面為採樣站，分別利用理化水質之多變數法、藻類群落變異指數法及王氏綜合評估指數法評估民國72年至78年水庫優養等級。並以迴歸分析方法分析各水質評估方法間之相關性。水質評估方法很多，王氏綜合評估指數法為結合理化水質與藻類相之一種綜合評估方法。其所得之結果較能代表水質優養情形。根據王氏綜合評估指數法評估水質結果發現以年度來說，民國76年及78年水質最差，各月份斷面皆無貧營養等級出現。民國75年水質出現貧營養等級之斷面較多，故該年水質最佳。以季節來說，夏季水質最差，各斷面多屬優養等級。冬季最好，春秋季次之。以斷面來說，上游斷面水質較差，下游斷面則較佳。根據王氏綜合評估指數與北卡指數（NCTSI）及卡爾森指數（Carlson TSI）間之迴歸分析所得之相關係數顯示除民國78年稍差外，其餘各年皆0.8以上。王氏綜合評估指數與藻類群落變異指數間相關稍差，但亦在0.4-0.8之間。
並列摘要
Tecchi Reservoir is located at upstream of Tachia Stream in Central Taiwan. Due to over use of land for agriculture on watershed, lake water has been contaminated and eutrophied by agriculture runoff for many years. Four stations were chosen and sampled to assess the temporal and spatial variation of the eutrophication status from 1983 to 1989 by using multiple parameters index, algal community diversity index (Algal DI) and Wang's comprehensive ranking index (WI). Regression analyses were used to measure correlation coefficcients between different classification methods. Among the different eutrophication classification methods, Wang's comprehensive ranking index integrate the physical, chemical and biolgical parameters that provide a better means to measure the trophic state of a body of water. The result of WI classification method shows that water quality in 1987 and 1989 were the worst trophic status among 7 year, whereas a better water quality appears in 1986. It also shows that trophic state in summer is the most highly enriched ranking season, whereas trophic state in winter is better than that of spring and autumn. The results also indicate water quality at lower reaches station are better than that of upper reaches stations. Regression analyses among WI and North Carloina trophic state index (NCTSI) as well as Carlson trophic state index (Carlson TSI) indicate highly correlation existed with an average correlation coefficient of 0.8. Although correlation between WI and Algal DI are not as good as that of NCTSI and Carlson TSI, correlation coefficients varies from 0.4 to 0.8.