河川水質監測站網設計之研究

Network Design for River Water Quality Monitoring

杜有俊(DO HUU TUAN)

指導教授 ： 駱尚廉

國立臺灣大學/工學院/環境工程學研究所/博士(2012年)

https://doi.org/10.6342/NTU.2012.02578

摘要

對於流域開發與決策，河川水質監測數據為相當基本之所需資料，而採樣站之決定為監測站網設計之重要因子之一。過去大部分研究主要以數學方法進行監測站網設計，而在流域中的人類活動則無法藉由此方法加以仔細考量之。
營養鹽濃度對於水資源的品質以及優養化可能性為相當重要之因子，而營養鹽監測站網是一個重要的資料來源，它可以提供河川營養鹽的汙染狀況。輸出係數模式常用於非點源汙染之研究，而僅有少部分談論到利用非點源汙染與輸出係數模式以設計水質監測點。
河川水質採樣頻率對於河川水質監測站網亦是一個重要的部分，而對於站網內各採樣站而言，一個合適的採樣頻率可使量測資料更接近真實狀況，有助於管理者與決策者對於河川水質之瞭解。階層分析法(AHP)是一個有效的決策分析方法，可根據多準則計算權重因子以解決複雜的問題。
本研究提出一套新穎的水質監測站網設計方法，用以挑選具有代表性之河川水質採樣點。此方法結合河川混合長度、人類活動與地理資訊系統(GIS)，以獲得採樣點應座落的位置。同時，將創新利用一針對土地利用之污染潛勢評分模式(Potential Pollution Score, PPS)，以依據重要性進行採樣位置優先選取之分類。而此方法被應用於新店區與烏來區的河川系統中。而在本研究範圍內，下游的都會區與農業區為主要的非點源污染來源，也為主要的研究區域，在新店區與烏來區共建議了7個河川採樣點。
本研究提出一個新的設計營養鹽監測點方法，當中包含辨別污染來源、設計採樣點與頻率。同時利用此方法在翡翠水庫上游設計營養鹽監測點後，該研究結果發現農業區佔全研究區域僅7.24%，然而每年卻釋出45,795公斤之非點源污染量，佔全研究區域之41%。此外，在翡翠水庫上游的研究區域內，根據最佳條件分析後，共決定四點採樣位置以及各點之適當採樣頻率。
最後，本研究中應用AHP以提出一新方法去設計河川水質採樣頻率，此方法結合變數的權重因子與採樣站的相對權重，以決定各站每月與每年之採樣頻率。本研究將之中應用於景美溪與新店溪之水質站網設計。研究結果顯示，應增加寶橋、中正、華中與華江站。此外，於一月、四月與十月的採樣次數相較於其他月份也應增加。

關鍵字

河川監測站網 ； 河川水質監測 ； 河川混合長度 ； 污染潛勢評分 ； 營養鹽輸出係數 ； 河川採樣頻率

並列摘要

River water quality monitoring data are essential to water basin development and decision making. The location of sampling stations is one of the most critical factors in monitoring network design. Most previous studies have focused on mathematical aspects of monitoring network design, whereas human activities within a river basin are often not considered comprehensively.
Nutrient concentration is an important factor in identifying the quality of water sources and the likelihood of eutrophication. A nutrient monitoring network is an important information source that provides data on the nutrient pollution status of rivers. Export coefficient models have been widely used to study non-point source pollution. However, there has been little discussion about applying non-point source pollution and export coefficient modeling to design sampling points for monitoring.
River water quality sampling frequency is an important aspect of the river water quality monitoring network. A suitable sampling frequency for each station as well as for the whole network will provide a measure of the real water quality status for the water quality managers as well as the decision makers. The Analytic Hierarchy Process (AHP) is an effective method for decision analysis and calculation of weighting factors based on multiple criteria to solve complicated problems.
In this study, a new water monitoring network design procedure is introduced to identify representative river water quality sampling locations. The new procedure combines river mixing length, human activities, and geographic information systems (GIS) to locate position of sampling points. An implementation of a new potential pollution score (PPS) model of land use helps to classify the importance of each sampling point prior to selecting the most appropriate locations for an entire river system. The new procedure is applied on river system of Xindian City and Wulai Township. With the study area, urban and agriculture are mainly concentrated in the downstream area and were the primary non-point pollution sources in this region. Seven sampling points are proposed to monitor river water quality in the Xindian City and Wulai Township.
In addition, a new procedure providing a comprehensive solution was proposed to design nutrient monitoring points, from identifying pollution sources to designing sampling points and frequencies. Application of this procedure to design nutrient monitoring points upstream from the Feitsui reservoirs, Taipei, Taiwan, indicated that agriculture occupied only 7.24% of the area, but it released 45,795 kg/yr, or 41%, of the total nutrient load from non-point sources. Additionally, the optimization conditions defined four sampling points as well as the frequency of sampling at those points in the upstream of the Feitsui reservoirs.
Finally, this study introduces a new procedure to design river water quality sampling frequency by applying the AHP. We introduce and combine weighting factors of variables with the relative weights of stations to select the sampling frequency for each station, monthly and yearly. The new procedure was applied for Jingmei and Xindian river system. The results showed that sampling frequency should be increased at Po, Jhongjheng, Hua Zhong, and Hua Jiang stations. In addition, the number of samples in January, April, and October should be increased relative to the other months.

並列關鍵字

river monitoring network ； river water quality monitoring ； river mixing length ； potential pollution score ； nutrient export coefficient ； river sampling frequency

參考文獻

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