투수성 포장과 침투 트렌치를 고려한 수정 SWMM의 개발 및 적용

Abstract

An infiltration facility is operated as a method of reducing flood discharge of urban rivers and increasing flow during the dry season. The present study modified the existing SWMM model to simulate permeable pavement and infiltration trenches. In the course, errors in evaporation treatment and the groundwater output function were also corrected. To test the adequacy of the modified program, the simulation results of SWMM was compared with the results of physical model experiments on permeable pavement and infiltration trenches. The program modified in consideration of permeable pavement and infiltration trenches was applied to the watershed of Hakuicheon, which is an upstream tributrary of Anyangcheon, and the effect of the infiltration facilities were analyzed. First, we analyzed the hydrological cycle structure of the entire Anyangcheon watershed as well as the Hakuicheon watershed. Changes in the impervious area caused by urbanization and the consequent changes in the runoff characteristic were analyzed at the Gocheokgyo for the Anyangcheon watershed and at the Bisangyo for the Hakuicheon watershed. Urban impervious areas were distinguished by analyzing the land uses using LANDSAT TM satellite images between 1975 and 2000. The results of analyzing the effect of urbanization on hydrological cycle showed that surface runoff increased from 50 % in 1975 to 65 % in 2000 and subsurface runoff decreased from 13 % to 7 % in the entire Anyangcheon watershed. In the Hakuicheon watershed, surface runoff increased from 55 % in 1975 to 62 % in 2000 and subsurface runoff decreased from 11 % to 7 %. If we make the impervious areas in the Hakuicheon watershed permeable by 10 %, the low flow (Q_275) increases by 3 % and the drought flow (Q_355) by 17 % at the Bisangyo stage station. As to infiltration trenches, if five to ten trenches with a length of 100 m are constructed at each Hakuicheon subcatchment, the low flow increased by around 1 % and the drought flow by around 9 %. With the modified SWMM, we can analyze the effects of infiltration trenches and permeable pavement on the recovery of water flow during the dry season in urban watershed.