水里溪上游集水區溪流水質的空間變異分析
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Date
2007-03-01
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國立臺灣大學理學院地理環境資源學系
Abstract
本研究目的在於探討水里溪上游集水區溪流水質的空間變異特性，從2004年1月起至2005年2月止，每個月分別至研究區五個監測站調查溪流水量並取水樣，分析14個水質參數，包括電導度、pH值、水溫、溶氧量、陽離子(Ca2+、Mg2+、Na+、K+、NH4+)及陰離子(F-、Cl-、SO42-、NO3-、HCO3-)等，再以多變量統計方法包括因素分析及集群分析加以探討溪流水質特性。研究結果顯示，研究區溪流水質偏弱鹼性，主要陽離子為Ca2+及Mg2+，主要陰離子為HCO3-及SO4-2。Na+、Ca2+、Mg2+、HCO3-等離子濃度及電導度隨著流量的增加而減少，但NO3-離子濃度則隨著流量的增加而增加，在WC-4及WC-5測站中SO4-2的濃度明顯偏高，此與不同的地質特性有關。透過因素分析後得知，研究區的溪流水質與母岩風化、逕流路徑、人為活動、氣溫變化、植生作用及大氣沉降等因素有關，另外，經由集群分析後可以把監測站區分為3組。
The purpose of this study was to understand the spatial variability of stream water quality in the upper Shui-Li Creek watershed. Monthly stream discharges were investigated and water samples were collected at 5 monitoring sites in the study area during the period from January 2004 to February 2005. From the samples, 14 stream water quality parameters were analyzed, including conductivity, pH, water temperature, dissolved oxygen, cations (Ca2+, Mg2+, Na+, K+, and NH4+) anions (F-, Cl-, SO42-, No3-, and HCO3-) ionic concentrations. The multivariate statistic methods including factor analysis and cluster analysis were applied to analyze steam water quality characteristics. Results showed that steam water had weak alkalinity. Dominant cations of stream water were Ca2+ and Mg2+, while dominant anions were HCO3- and SO42-. Conductivity, concentrations of Na+, Ca2+, Mg2+, and HCO3- in stream water decreased with the increase of discharge. However, concentration of NO3- increased with the increased of discharge. Higher SO42- concentrations at the monitoring sites of WC-4 and WC-5 were primarily due to different geological characteristics. On the basis of factor analysis, stream water quality in the study area was closely related to geologic weathering, runoff pathways, human activities, air temperature change, vegetative functions, and atmospheric deposition. In addition, monitoring sites were classified into 3 groups using cluster analysis.
The purpose of this study was to understand the spatial variability of stream water quality in the upper Shui-Li Creek watershed. Monthly stream discharges were investigated and water samples were collected at 5 monitoring sites in the study area during the period from January 2004 to February 2005. From the samples, 14 stream water quality parameters were analyzed, including conductivity, pH, water temperature, dissolved oxygen, cations (Ca2+, Mg2+, Na+, K+, and NH4+) anions (F-, Cl-, SO42-, No3-, and HCO3-) ionic concentrations. The multivariate statistic methods including factor analysis and cluster analysis were applied to analyze steam water quality characteristics. Results showed that steam water had weak alkalinity. Dominant cations of stream water were Ca2+ and Mg2+, while dominant anions were HCO3- and SO42-. Conductivity, concentrations of Na+, Ca2+, Mg2+, and HCO3- in stream water decreased with the increase of discharge. However, concentration of NO3- increased with the increased of discharge. Higher SO42- concentrations at the monitoring sites of WC-4 and WC-5 were primarily due to different geological characteristics. On the basis of factor analysis, stream water quality in the study area was closely related to geologic weathering, runoff pathways, human activities, air temperature change, vegetative functions, and atmospheric deposition. In addition, monitoring sites were classified into 3 groups using cluster analysis.