Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/33296
標題: 大坑溪集水區水體污染程度之研究
A Study on River Pollution Level of Ta-Keng Creek Watershed
作者: 施慶煌
關鍵字: 大坑;集水區;水質
出版社: 水土保持學系
摘要: 
本研究選定大坑溪集水區設置五個水質分析採樣監測站;以探討該集水區之污染現況。水質檢驗項目包括:流量、水溫、pH、導電度(EC)、溶氧(DO)、懸浮固體物(SS)、濁度、生化需氧量(BOD)、氨氮(NH3-N)、總磷(T-P)、總氮(T-N)、硝酸鹽氮(NO3-N)、亞硝酸鹽氮(NO2-N)、總凱氏氮(TKN)、大腸桿菌等。水質分類多屬甲級,RPI平均積分為2.0以下屬稍受~未受污染等級,而豐水期與枯水期水質及流量之差異比較,枯水期顯較豐水期為差。
由地理資訊系統(Geographic Information Systems:GIS)分析大坑地區之衛星影像資料,921集集大地震後大坑溪集水區約有 5.28公頃新崩塌地產生,晴天時SS監測數值地震前、後各監測點差異不大,監測值多介於2mg/L∼10mg/L之間;惟比較地震前後兩場日雨量(37∼38mm)資料,降雨時地震後SS之測值較地震前為高。
結合DTM資料經由OM30軟體分析得知集水區泥砂產量多小於5tons/yr佔總面積58.05%;大於35tons/yr多分布於河道附近佔總面積24.68%。震後新崩塌聚積於大坑溪中、上游;經各監測站水質分析結果濁度、懸浮固體物(SS)之總平均值相較(雙連橋108NTU/208.7mg/L、廣德橋109.7NTU/174.1mg/L、廣盛橋68.4NTU/60.4mg/L、光明橋40.7NTU/67.1mg/L)顯示中、上游(雙連橋、廣德橋)之濁度、懸浮固體物(SS)均較中、下游(廣盛橋、光明橋)之數值明顯為高,可知震後之新崩坍地日後對大坑溪水質惡化有直接影響。

This study set up five gathering stations to sample stream water monthly for examining pollution status of the streams in Ta-Keng watershed. Analysis item includes discharge, water temperature, pH, EC, DO, SS, turbidity, BOD, HN3-N, T-P, T-N, NO3-N, NO2-N, TKN and coliform. Results show that water quality in the watershed is graded as class A according to the landscape surface water classification and standard. Stream water quality belongs to slightly and/or not polluted class using the calculation of River Pollution Index (RPI). It is obvious that water quality in dry season has worse index toward that in rainy season.
Using geographic information system and image analysis, there are 5.28 ha landslides occurred in the watershed of interest after the hit of earthquake on SEP. 21st 1999. No obvious variation of SS (2mg/L∼10mg/L ) detected on the sunny day during this study. However, two-single event precipitation (37~38mm) selected before and after the quake, there is a dramatic rising in SS detected after the quake.
Watershed analysis show that about 58.05% of total area having the amount of annual sediment yield less than 5 tons. The sites where sediment yield more than 35 tons/yr occupied 24.68% of total area are located at the riparian. Most landslides induced by the quake occurred at the upstream of Ta-Keng creek. The average turbidity and SS (Shuang-Lian bridge 108 NTU/208.7mg/L, Goang-Der bridge 109.7NTU/174.1 mg/L, Goang-Shenq bridge 68.4NTU/60.4 mg/L, Guang-ming bridge 40.7NTU/67.1 mg/L) monitored at the sampling stations show that the bridges located at the upstream having higher turbidity and SS comparison with those at the downstream. The landslides caused by the quake plays an important role on the worse water quality of Ta-Keng creek.
URI: http://hdl.handle.net/11455/33296
Appears in Collections:水土保持學系

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