水理水質模式於嘉義縣朴子溪流域之建立及運用

Development and application of hydraulic and water quality models for Pou-Tze Stream Area in Chiayi County

國內河川污染嚴重，已引發公共衛生相關問題。若要解決河川污染問題，應先對河川之水理水質特性確實掌握，而河川水理水質模式已常被運用來模擬河川內水質之變化情形，瞭解河川水質之狀況，並作為評估水質改善效益及改善目標達成之依據。由於國內大部份河川均已受不同程度之污染，環保署目前正為積極改善國內河川水質而努力。河川水理水質模式之建立不僅可作為水質改善目標之監控工具，同時將利於有效掌控河川各河段之水質變化情形。因此，本文將闡述以嘉義縣朴子溪為例，利用環保署水質監測站歷年在該水體監測之水理及水質資料及研究期間之實測資料，建立適用於該河川之水理水質模式，並完成模式之率定及驗證等工作。在模擬河段的劃分上，乃以嘉義縣灣內大橋為分界，以上河段以QUAL2E模式進行水理、水質分析演算，以下河段則以HEM-2DT模式進行模擬。研究結果發現所建立之水理水質模式，均能有效模擬嘉義縣朴子溪之水質狀況，故研究成果除可作為推估河川水質污染或改善成效之運用外，同時也能提供後續相關研究或實務技術之使用及環保相關政策擬定等之參考依據。

Heavy pollution of Taiwan’s rivers have become a public health concern. The river water quality model has often been applied to characterize variances in water quality, understand the river water quality, and to evaluate the efficiency and the objectives of water quality improvement. Since most of the rivers in Taiwan are heavily polluted, Environmental Protection Administration (EPA) has being active in improving river water quality. The establishment of this water quality model can not only be used as a monitoring tool for the achievement of water quality improvement but can also be effectively used to control the variance of water quality. Therefore, the Pou Tze Stream in Chiayi County was selected for this study, and the water quality model was developed using hydraulic and water quality data. This model can then be used for modeling the water quality of Pou Tze Stream. The Wa-Nei Bridge in Chiayi County was used as the boundary line in the study. The QUAL2E model was applied to the river sections upstream of this bridge, and the HEM-2DT model was used for the river sections downstream of this bridge. The hydraulics and water quality data of this river, which are shown on the website of Taiwan EPA, were collected from the monitoring stations of EPA and the measured data provided by the company cooperating with the EPA. In this study, the water quality modeling was established, assured, and proved. The results of this study can be used for the evaluation of river water quality and for predicting the efficiency of water quality improvement. It is also expected that the water quality model established in this study can be applied in subsequent research studies and practical techniques and serve as a reference in the planning of environmental policies.