In order to provide the basic information for the water quality modeling, the water pollution indicators of Sin stream and Keumho river flowing through Taegu city were measured, and the periodical variations of these indicators were studied under the condition of stagnating for 19 days. For this experiment, three sampling sites(Sungpook bridge, Mutae bridge and Gangchang bridge) were selected. Sungpook bridge is located most down the Sin stream, Mutae bridge and Gangchang bridge are located on the lower Keumho river. The results were as follows. 1. The values of water pollution indicators measured at Mutae bridge were pH 8.7, TSS 51㎎/ℓ, TS 383㎎/ℓ, Cl^- 60.68㎎/ℓ, turbidity 32FTU, DO 8.58㎎/ℓ, oxygen deficit 2.02㎎/ℓ, COD 16.32㎎/ℓ, organic carbon 13.60㎎/ℓ. 2. At Gangchang bridge located down more than Mutae bridge, the values of these indicators were pH 8.0, TSS 26㎎/ℓ, TS 737㎎/ℓ, Cl^- 90.59㎎/ℓ, turbidity 37FTU,DO 3.49㎎/ℓ, oxygen deficit 7.11㎎/ℓ, COD 28.02㎎/ℓ, organic carbon 14.28㎎/ℓ. 3. At Sungpook bridge, the values of these indicators were pH 8.3, TSS 145㎎/ℓ, TS 344㎎/ℓ, Cl^- 32.51㎎/ℓ, turbidity 60FTU, DO 6.53㎎/ℓ, oxygen deficit 4.07㎎/ℓ, COD 43.79㎎/ℓ, organic carbon 11.03㎎/ℓ. 4. At Mutae bridge and Sungpook bridge of which initial DOs were high, DOs have decreased under the condition of stagnating for 7 days and increased after that time. On the contrary, at Gangchang bridge of which oxygen deficit was very high(7.11mg/l), DO have increased under the condition of stagnating for 13 days and decreased after that time. 5. All the samples showed the quick decrease of CODs and organic carbons under the condition of stagnating for 19 days. Nevertheless, at Sungpook bridge of which initial COD was very high (43.79㎎/ℓ), the value of COD measured at the last day of experiment was still high(21.35㎎/ℓ), because of a large quantity of reducing inorganic matters. 6. All the samples didn`t show the distinct decrease of turbidities because of a large quantity of nonbiodegradable inorganic solids.

• 박병윤 | Byoung Yoon Park