The water quality simulation and uncertainty in Hsin-tien river

• Main Authors: Kang,Chin-Chan, 康晉展
• Other Authors: Lo,Shang-Lien
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/46890558322490603722

碩士 === 國立臺灣大學 === 環境工程研究所 === 84 === The purpose of this study was to simulate the water quality of Hsin-tien River by using water quality model QUAL2E, ESTUARY, and STREAM. Results showed that biochemical oxygen demand (BOD) decreased before but increased after the Ching-tarn embankment. The highest BOD which exceeded Taiwan EPA water quality criteria was found at Bih-tarn bridge. Dissolved oxygen (DO) decreased downstream but still exceeded the 5.5 mg/L limit. Next, the water quality of Hsin-tien River was predicted at Q75 and Q90 flow in 2011. BOD will pass water quality criteria at Q75, but it will not pass at Q90 because the Hsin-wu sewer system passes sewage into the river after Bih-tarn bridge. However, DO will still pass the criteria in the prediction. In this study, sensitivity analysis, first-order error analysis (FOEA), and Monte Carlo simulation (MC) were performed to simulate the water quality of Hsin-tien River at Q75 and Q90 flow in 2011, and the influences of uncertainty factors were discussied. Results showed that the effect of K1 is significant for BOD but insignificant for DO. Sb does not influence DO. Upstream boundary conditions domaintes the simulation results. Furthermore, we used FOEA and MC to simulate water quality and calculated the risk probability. At the same design flow, the calculated probability of FOEA is higher than MC.