- 學位論文
台灣水庫水質及其管理指標之評析
Evaluation of Reservoir Water Quality and its Management Index in Taiwan
摘要
為掌握公共給水水源之水庫水質良窳與檢視水庫集水區水質保育成效，台灣環保署使用卡爾森指標(Carlson trophic state index, CTSI)，以總磷(TP)、葉綠素a(Chl-a)及透明度(SD)之水質參數計算CTSI值來判定水質營養狀態。做為水源用的水庫遭受汙染呈現優養化後，其水質安全性必遭質疑。然而國內研究較少檢討優養化水質與飲用水水源水質標準關聯性，尤其離島地區之水庫水質。 本研究以台灣本島20座主要水庫及離島地區(澎湖、金門、連江)水庫為對象，藉由環保署水質監測網之2011年至2018年水質資料，整理近8年水庫之水質現況並將本島之水庫水質資料進行優養化指標評估比較，研究目的為: (1)本島主要水庫之各項水質現況評析、(2)本島水庫管理指標之研議、(3)離島地區(澎湖、金門、連江)水庫之各項水質現況評析。 研究結果顯示本島20座主要水庫大多處於普養狀態，而部分水庫(包括明德、鏡面、鳳山及澄清湖水庫)長期處於優養狀態；離島則有96.4%的水庫長期處於優養化狀態。在水質優養化判定方面，由於本島和離島地區水庫之CTSI最主要影響因子皆為SD，而透明度會受到懸浮固體(SS)的影響，本島水庫SS與SD之相關性r為0.84，因此採用[TSI(TP)+ TSI(Chl-a)]/2指標大於50較為合適。若以單一指標參數葉綠素a來判定水質營養狀態，則採用美國環保署標準7 µg Chl-a/L或 OECD年平均值8 µg Chl-a/L。 若水庫水質管理目的回歸地面水體水質分類標準，本島甲類水體及乙類水體之水庫近8年水質TP達成率平均各別為72.8%與73.3%，應削減集水區TP與提高達成率作為施政目標，同時檢討甲類水體TP達成率偏低之水庫如寶山28.1%、石門31.3%及澄清湖25%；乙類水體之鳳山水庫達成率則為0%。然而， CTSI值非法規標準值，本島部分水庫雖處於優養化，但水質之氨氮(NH3-N)及化學需氧量(COD)皆符合飲用水水質標準，可正常供水；水質優養化且COD超過標準值之離島水庫，即澎湖、金門及連江地區，其比率分別為60%、82%與16%。且離島地區相較於本島之水庫水質COD達成率則偏低。
並列摘要
In order to grasp public service water source quality of reservoir and examine the effect of water quality conservation in reservoir watershed, Taiwan EPA uses water quality parameters such as total phosphorus (TP), chlorophyll a (Chl-a) and transparency (SD) to calculate the Carlson trophic state index (CTSI) and determine water quality trophic status of reservoirs. The water quality safety of the reservoirs used as the water source will be questioned after they are polluted (e.g. eutrophication). However, there are less domestic researches about the correlation between eutrophication and source quality standard of drinking water, especially reservoirs of outlying islands. In this study, 20 major reservoirs of Taiwan island and other reservoirs of outlying islands (Penghu, Kin-men and Lien-Chiang) are investigated. Based on the water quality data of the EPA Water Quality Monitoring Network, the water quality of the reservoir has been analyzed for the past 8 years from 2011 to 2018. The water quality data of Taiwan island are compared and evaluated for the eutrophication index. The purposes of this research are: (1) Evaluating the current condition of various water quality parameters in major reservoirs of Taiwan island, (2) Discussion on the reservoir management index of Taiwan island (3) Evaluating current condition of various water quality parameters of outlying islands reservoirs. The result shows that most of the major reservoirs are mesotrophic and some reservoirs, including Mingde Reservoir, Jingmian Reservoir, Fongshan Reservoir, and Chengcing Lake Reservoir, have been eutrophic for a long time. Besides, 96.4% reservoirs in the outlying islands are in a state of long-term eutrophication. Since the major factor affects CTSI of main island and outlying island is SD, and SD is affected by SS, the correlation coefficient(r) is 0.84. Therefore, using [TSI(TP)+ TSI(Chl-a)]/2 index to determine eutrophication is more suitable than CTSI in Taiwan. If the single parameter index Chl-a is used to determine the trophic state of the water, then the standard of U.S. EPA (7 μg Chl-a/L) or OECD annual average value (8 μg Chl-a/L) is adopted. In the part of surface water quality classification standard, the average water quality TP achieving rate of class I water body reservoir and class II water body reservoir in Taiwan island for the past 8 years are 72.8% and 73.3%, respectively. Thus, reducing TP in reservoir watershed and improving TP achieving rate should be the policy objectives. In addition, the class I water body reservoir and class II water body reservoir, which are low TP achieving rate such as Baoshan Reservoir (28.1%), Shihmen Reservoir (31.3%), Chengcing Lake Reservoir (25%), and Fongshan Reservoir (0%) should be reviewed. However, CTSI is not an official standard in Taiwan. Despite some of reservoirs in Taiwan island are eutrophic, the concentration of NH3-N and COD meet the drinking water quality standard. Therefore, the water can be supplied from reservoirs. The percentage of reservoirs, which are eutrophication and COD over proof, in Penghu, Kinmen and Lienchiang are 60%, 82%, and 16% respectively. Moreover, the COD achieving rate of reservoirs in outlying islands is lower than that of Taiwan island.