牡丹水庫集水區非點源污染模擬及風險分析

劉柏廷(Po-Ting Liu)

指導教授 ： 郭振泰

國立臺灣大學/工學院/土木工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01620

摘要

牡丹水庫位於四重溪上游，水庫係集取四重溪上游之支流－汝仍溪與牡丹溪流域之水量而成，有效容量3056萬立方公尺，集水區面積69.2平方公里。由88、89年水質採樣監測，比較兩年水質變化趨勢，Carlson’s TSI值平均50上下，顯示水庫有優養化的趨勢，所以如何有效控制河川水量及水質進入水庫，集水區保育及管理是當前重要之課題。
本文採用美國環保署發展的BASINS模式中之非點源污染模式NPSM進行集水區非點源污染及傳輸量模擬。首先模擬民國89∼92年之水文，以89、90年資料檢定，並以相同參數驗證91、92年流量，證實模擬結果良好，確認其可靠性及適用性，再將暴雨採樣資料及年淤積量檢定驗證泥沙濃度，並以暴雨水質資料模擬水質狀態後，推估全年集水區污染物產量做為提供集水區治理規劃之參考。進一步利用均值一階二矩法及Latin Hypercube Sampling取樣法找出影響模式之關鍵參數，探討水質參數對模式輸出之不確定性，並採用均值一階二矩法、Latin Hypercube Sampling取樣法及Harr’s點估計法分析河川水質濃度之風險。
結果顯示，NPAM模式能有效模擬長時間的集水區水理水質傳輸變化。牡丹水庫集水區全年污染負荷量，總氮之非點源污染負荷量約為89595kg/yr，總磷約為2526kg/yr，單位面積之負荷量總氮約為12.95kg/ha/yr，總磷約為0.36 kg/ha/yr。

關鍵字

水質 ； 非點源污染 ； 風險分析

並列摘要

Mu-dan Reservoir was located in the Pingtung and converged by Mu-dan River and Ru-Reng River, the branch of Si-Chong River. Its drainage area is 69.2 square kilometer, and its effective capacity is 30,560,000 cubic meters. Compared with the changing trend of 1999 and 2000 by the sampling of water quality, the Carlson’s TSI values are about 50. It shows that the water of Mu-dan Reservoir is in the trend of eutrophication. Therefore, how to efficiently control the quantity and quality of water infusing into Mu-dan Reservoir and the preservation and administration of drainage area are important issues (to protect watershed ecology).
NPSM, one of BASINS model developed by U.S. Environmental Protection Agency(EPA), is adopted in the study to simulate the transferred quantity of the river and non-point source of the drainage area. The discharge was calibrated with the data in 2000 and 2001, and verified with the data in 2002 and 2003, for confirming the model can be used in this study. Suspended solids and water quality was simulated with the sampling data of storm, then the total pollutant loading of the drainage area could be estimated for watershed managemenr. Latin Hypercube sampling(LHS) and the mean first-order reliability method are applied to determine the parameters significantly affecting uncertainty in the simulated water quality concentrations and analyze the risk of water quality concentrations.
The result shows that NPSM can efficiently simulate the change of the chronic water quality in drainage area. Annual non-point loading of total nitrogen was about 89595kg/yr, total phosphorus was about 2526kg/yr. The total nitrogen per hectare was about 12.95kg/ha/yr, and the total phosphorus per hectare was about 0.36 kg/ha/yr.

並列關鍵字

BASINS ； Water Quality ； non-point sources

參考文獻

53. 陳昶憲等，「山坡地集水區頻率洪流推估—以台北市郊內雙溪為例」，中華水土保持學報，第28卷，第2期，pp.178-483，民國86年。

1. Adamus C. L. and Bergman M. J., “Estimating Nonpoint Source Pollution Loads With GIS Screening Model”, Water Resources Bulletin, 1995.

3. Beck, M. “Water Quality Modeling: A Review of the Analysis of Uncertainty”, Water Resources Research, Vol. 23, No.8, pp.1939-1942, 1987.

5. Burges, S. J. and D. P. Lettenmaier, “Probabilistic methods in stream quality management”, Water Resources Bulletin, Vol.11, No.1,pp.115-130, 1975.

6. Donigian, A.S., Jr. and H.H. Davis, Jr. 1978. User's Manual for Agricultural Runoff Management (ARM) Model, U.S. Environmental Protection Agency, EPA- 600/3-78-080.