Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/27843
標題: 南投烏溪流域河水之氫氧同位素研究
Hydrogen and Oxygen isotopic studies of rivers in Wuchi watershed, Nan-Tou
作者: 王淑姿
Wang, Shu-Zi
關鍵字: Wu-Chi watershed;烏溪流域;Tao-Zhi typhoon;Hydrogen and Oxygen isotopic;hydrological characteristics;桃芝颱風;氫氧同位素;水文特性
出版社: 土壤環境科學系
摘要: 
河川是台灣水資源最重要的來源,但受限於水文觀測站的設置,許多中上游集水區的水文循環特性無法全盤掌握。本研究就地緣之便,選擇台灣流域面積第四大(2025km2),支流多、流域分佈範圍廣、水文站設置不普遍,且河川上游受人為開發破壞現象較少的烏溪流域(支流:北港溪、南港溪、貓羅溪和大里溪)作為研究範圍,嘗試將流域水文背景資料與氫氧同位素組成結合,以檢視流域上游地區之集水區水文循環特性。此外,由於採樣期間遇桃芝颱風來襲,因此本研究亦嘗試以同位素組成進行桃芝颱風事件性的水文分析,以追溯桃芝降雨於烏溪流域的移動趨勢,進而檢視烏溪上游集水區涵養雨水的概況。
結合流域水文背景資料與氫氧同位素組成,檢視烏溪流域上游之集水區水文循環特性結果顯示,貓羅溪為烏溪流域中,唯一受少量雨水補注,其河水同位素即有較明顯變化的支流,且上、下游河段的採樣點同位素組成呈不相關顯示,其水文循環特性較不穩定,應與該區高度人為開發、干擾有關。南港溪雖有多條支流,但其上、下游河段之採樣點同位素組成具高度相關(R>0.7)顯示,其水文循環特性屬穩定型態。北港溪之河水來源簡單且同位素變化穩定,顯示其水文循環特性亦屬於穩定。屬於人工整治之大里溪的河水來源可能與大甲溪之水體引用排放有關。以氧同位素組成進行桃芝雨水之水文分離,可將烏溪流域上游未具水文站的區域依其涵養雨水能力分為三類,其中貓羅溪上游集水區為涵養雨水能力較差的區域(雨後之保水百分比小於40%),而南港溪上游之眉溪支流為涵養雨水能力最佳的區域(保水百分比大於60%);其餘地區介於二者之間。本研究顯示:結合一般水文資料和同位素組成,可以有效了解烏溪流域上游集水區之區域性和事件性的水文循環特性。

River provides the most important source for Taiwan water resources. Due to the establishment limitation of hydrological stations, many essential hydrological phenomena cannot get a better understanding in the upper part of a watershed. Because of geographical convenience, this study chose the Wuchi as the target to study the upper-stream hydrological characteristics of its watersheds by stable isotope compositions complementing with the traditional hydrological parameters. Wuchi is the fourth largest river in terms of area (2025km2) in Taiwan. It has many tributaries, and four watersheds (Peikangchi, Nankangchi, Maolochi and Talichi) with relatively less anthropogenic activities in the upper-stream parts. In addition, Typhoon Toraji occurred during the study period. A hydrological separation analysis was conducted for the particular typhoon event. The aims were to trace the effect of typhoon precipitation on the watersheds and evaluate their water-retaining capacities.
Stable isotope compositions for water samples collected from spots spreading over major tributaries showed that Maolochi exhibited large variations during the dry period, indicating an unstable state for its watershed, probably due to a relatively high degree of anthropogenic activity. Nankangchi is comprised of many small tributaries, but isotopic variations showed a homogeneous pattern from upper to lower stream parts for both wet and dry periods, suggesting its watershed is relatively stable. Peikangchi has a simple source of stream flow, and displayed also very little variations in isotopic compositions, implying its stable nature of the watershed. Talichi has been engineering regulated and showed distinct isotopic compositions with other watersheds of Wuchi. The water sources of Talichi may be derived from Tachiachi. Isotopic separation analysis showed that there are three types with regards to water-retaining capacities. Maolochi represents the low type with a capacity value less than 40%. The Meichi of Nankangchi has the capacity larger than 60% and can be classified as the high type. All others belong to the intermediate type with values between 40 and 60%. This study demonstrates that stable isotopes with traditional hydrological parameters can further understand upper-stream hydrological characteristics. The analytical results are valuable in landslide prevention and land management.
URI: http://hdl.handle.net/11455/27843
Appears in Collections:土壤環境科學系

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