The objectives of this study is to evaluate the total runoff yield, peak flow and peak flow travel time depending on the urbanization, return period and rainfall patterns at the downstream of Manchon urban watershed in TaeGu City. SWMM(Storm Water Management Model) is used for runoff analysis based on 5 different steps of urbanization and 4 different types of Huff`s quartile according to 8 return periods. It is analyzed that the order of total runoff yield according to rainfall patterns is Huff`s 4, Huff`s 2. Huff`s 3 and Huff`s 1 quartile, that of peak flow magnitude is Huff`s 2, Huff`s 1, Huffs`4 and Huff`s 3 quartile at present development ratio. under the 60, 70, 80 and 90% of urbanization to the 50% of urbanization by means of the rainfall patterns, the mean increasing ratio of total runoff yield for each case is 4.55, 11.43, 16.07 and 20.02%, that of peak flow is 5.82, 13.61, 17.15 and 18.83%, the mean decreasing ratio of peak flow travel time is 0.00, 2.44, 5.07, and 6.26%, the mean increasing ratio of runoff depth is 4.51, 11.42, 16.02 and 20.05%, respectively. the mean increasing ratio of total runoff yield by means of each return period & Huff`s 3 quartile is 4.86, 12.11, 17.14 and 21.56%, that of peak flow is 5.89, 13.97, 17.82 and 19.71%.
Therefore, as the result of this study, it can be used for principal data as to storm sewage treatment and flood damage protection planning in urban small watershed.

• 김성원(영남대학교 토목공학과) | Sung-Won Kim (Dept. of Civil Engineering, Yeongnam University)
• 조정석(대구대학교 토목공학과) | Chung-Seok Cho (Dept. of Civil Engineering, Taegu University)