底泥污染來源及傳輸模式調查計畫-以重點河川為例專案工作計畫
| 中文摘要 | 本計畫的核心在於建立合適的底泥管理架構及構建底泥水理水質模式，因此工作架構為參考國外執行經驗及現場調查結果，提出適宜管理架構及技術分析工具，並據此挑選案例進行污染傳輸模擬，透過情境模擬提出合適之行動管理策略建議。 計畫展開後，首先蒐集相關資料與文獻，並建立採樣規劃流程、河床地形測量及底泥地物探測等基本調查原則，並優選WASP 作為傳輸模式。在選定大漢溪為調查之河川河段後，隨即展開前述各項現場調查工作，藉由蒐集相關調查之模式參數，開始建置傳輸模式。 採樣調查結果顯示，底泥重金屬以銅、鋅、鎳等項目有超過上限值之狀況，其中又以「銅」超過上限值之樣品比例最高，若由污染空間分布來看，其污染程度以浮洲橋至新海橋段最為嚴重，污染可能來源應與週遭支流排水有關。河床地形測量結果顯示颱風暴雨對於大漢溪河道有明顯的沖刷現象，影響底泥在河床中的傳輸行為；地物探測結果顯示透地雷達與聲納法可作為底泥沉積厚度之初步篩選工具。 依據水質與底泥相關性分析與模式模擬結果顯示，若水質未改善，污染源仍持續排入，則底泥污染物濃度將逐漸上升，即便是將污染底泥清除後，經過若干年底泥濃度仍會持續上升並超過上限值；反之若水質改善，假設污染能夠零排放時，底泥即使未疏濬移除，濃度也將逐漸下降。依情境模擬結果，底泥挖除後若能配合有效地排放管制，使全流域水質達到標準值，則可有較長的時間(約30~40 年)維持底泥不超過品質指標上限值。 根據國外底泥管理架構與行動策略，底泥是否須進行復育或污染改善，應以底泥品質指標值為基準，作為管理行動起動點，並藉由生態及健康風險評估、整治效益等考量，及視場址特性及背景條件，評估實際造成之風險與效益，提供作為底泥管理或整治決策之考量。以大漢溪為例，調查結果及統計分析證明底泥與水質具有相關性，且主要支排流域之區域皆為易造成重金屬污染之行業別，因此底泥管理策略應優先管制事業污染排放，降低支流排水污染負荷量。 | ||
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| 中文關鍵字 | 河 川;傳 輸 模 式;底 泥 管 理 策 略 | ||
基本資訊
| 專案計畫編號 | EPA-100-GA102-02-A232 | 經費年度 | 100 | 計畫經費 | 21800 千元 |
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| 專案開始日期 | 2011/08/25 | 專案結束日期 | 2013/02/24 | 專案主持人 | 陳建宏 |
| 主辦單位 | 土污基管會 | 承辦人 | 黃雅潔 | 執行單位 | 美商傑明工程顧問(股)台灣分公司 |
成果下載
| 類型 | 檔名 | 檔案大小 | 說明 |
|---|---|---|---|
| 期末報告 | EPA100GA10202A232.pdf | 19MB |
Investigation for Contamination Source in Sediment and Its Transport Modeling - Take Internal Major
| 英文摘要 | The main focus of the project is the development of a sound framework for assessing and managing river sediment quality. A robust assessment tool (with hydrodynamic and water quality models for the sediment system) to track the fate and transport of heavy metals in rivers and sediments has been developed to support the assessment analysis. Deriving the experience from other countries,the results of the field work and model simulations in this study formed the basis of a comprehensive assessment and management framework, which was then used to evaluate a range of sediment restoration scenarios for the select river system. The assessment outcome was then incorporated into the management strategies and recommendations for the sediment clean-up effort. The project work started with data and information gathering and field program development for collecting hydrographic data of the river system and geophysical surveys of the sediment system. The water quality modeling framework, WASP from US EPA was adopted as the platform for developing the fate and transport model of the Dahan River in Taipei, selected as the target river system for this project. Subsequent field work conducted in the Dahan River provided the necessary data for model development, calibration, and verification of the model. Results from the field program revealed that existing levels of copper, zinc,and nickel in the Dahan River sediments exceed the water quality criteria with copper the metal most frequently violating the standard. The river portion between the Fu-Chou Bridge and Xinhai Bridge is found having the highest metal concentrations in the sediment as a result of the significant metal loads from sources in the watershed. Geophysical survey data indicated typhoons have a massive impact on the morphology of the river channel with significant erosion resulted from these events. In addition, results from the ground-penetrating radar and sonar readings suggest that they can be a useful screening tool to quantifying sediment transport (i.e. shoaling) in the Dahan River. The WASP model simulation results indicated that metal levels in the Dahan River sediments will continue to rise if no actions were taken to reduce the metal input. On-site removal of the contaminated sediments would only be a temporary measure to lower the metal contents in the sediment before the return of the contamination if the external inputs are not curbed. On the other hand, complete removal of the external metal input would significantly lower the metal levels in the river water followed by subsequent reductions of the metal contents in the sediment even without on-site dredging. Further, removing contaminated sediments along with control of the external inputs would be the preferred strategy to gradually restore the river sediment system to within the metal thresholds in 30-40 years. Sediment studies reported in the literature mostly suggest that sediment quality criteria be the basis for the development of control strategies and remediation actions to restore the sediment systems. Other contributing factors such as ecological and health risk considerations could also be incorporated into the assessment. The field data and model results from the Dahan River study indicated that the sediment quality is closely related to the water quality in the river with the external metal input as the major source of contamination. Controlling external metal inputs is therefore viewed as the top priority in the effort to restore the sediment system. | ||
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| 英文關鍵字 | river;transport model;management strategies and recommendations | ||