영산강에 대한 하천 수질예측모형의 민감도 분석 및 적용성 검토

Sensitivity Analysis and Application Test of Stream Water Quality Model on the Yongsan River

This study was performed to determine significant reaction coefficients and investigate the applicability of the QUAL2E model, which is commonly used for evaluation and prediction of stream water quality, on the Yongsan river. A sensitivity analysis was conducted to assess the relative importance of each reaction coefficient in the model. Reaction coefficients of the QUAL2E model were calibrated by using observed data, and calibration and verification were carried out by using Reliability index that evaluates the goodness of fit between observed data and simulated value. The major results of this study were as follows : 1. Sesitivity analysis showed that carbonaceous deoxygenation rate constant(k₁), rate of loss of BOD due to settling(k₃), organic nitrogen settling rate(σ₄), rate constant for the biological oxidation of NH₃ to NO₂(β₁), rate constant for the biological oxidation of NO₂ to NO₃(β₂) and organic phosphorus settling rate(σ₅) played an important role in simulation of the QUAL2E model on the Yongsan river 2. k₁. k₃, σ₄, β₁, β₂ and σ₅ were calibrated to be 0.13 ~0.18 day⁻¹, 0.003 ~0.015 day⁻¹, 0.015 ~0.02 day⁻¹, 0.21 ~0.49 day⁻¹, 0.675~1.825 day⁻¹, 0.002~0.003 day⁻¹ respectively. 3. Reliability index between the observed and simulated concentrations for calibration result were 1.97 for DO, 1.69 for BOD, 1.67 for NH₃-N, 2.39 for NO₃-N, 2.23 for DIS-P, respectively. 4. Reliability index between the observed and simulated concentrations for verification result were 2.14 for DO, 1.97 for BOD, 4.46 for NH₃-N, 2.92 for NO₃-N, 2.46 for DIS-P, respectively. 5. From the results of calibration and verification, it was found that application of the QUAL2E model as stream water quality model on the Yongsan river was possible.