• Journal of Korean Society on Water Environment
• /
• v.22 no.5
• /
• pp.815-823
• /
• 2006

The hydrologic cycle in urban catchment has been changed due to the expansion of impervious area by rapid urban development. In this study, the SWMM 5 (Storm Water Management Model 5) model was used to simulate the hydrologic cycle of the Dorimcheon catchment which suffers from the distorted hydrologic cycle as a typical urban catchment. This study compare continuous simulation of urban runoff combining the channel and sewer system with that of channel only in the Dorimcheon catchment. Continuous simulations of urban runoff were performed for the upstream basin of Dorim bridge. The urban impervious regions were processed by the land use analysis from LANDSAT_TM images. It was performed from 1975 to 2000 for every five years. Surface, groundwater and wastewater runoffs were additionally included in the simulations one at a time. Such simulations made it possible to evaluate those components quantitatively. The result of continuous simulation of urban runoff combining the channel and sewer system is that peak flow and recession are well simulated. The analysis results of urbanization effect on runoff are as follows: the surface runoff in 2000 increases to 64% of the whole precipitation whereas the surface runoff in 1975 amounts to 46% of the precipitation; the groundwater runoff in 2000 amounts to 6% and shows 8% decrease during the period from 1975 to 2000.

• Journal of Korean Society on Water Environment
• /
• v.22 no.2
• /
• pp.349-357
• /
• 2006

Nowadays, the discharges of urban streams during dry season are depleted because the hydrologic cycle in the watershed has been destroyed due to the expansion of the impermeable area, the excessive groundwater pumping, climate change, and so forth. The streamflow depletion may bring out severe water quality problems. This research are to investigate the hydrologic characteristics and to develop a technology to restore sound hydrologic cycle of Anyangcheon watershed. For the hydrological cycle analysis of the Anyangcheon watershed, continuous simulations of urban runoff were performed for the upstream basin of Gocheok bridge whose basin area covered 4/5 of the whole catchment area. The increase of impervious area by urbanization was analysed and its effect on urban runoff was evaluated. The SWMM 5 (Storm Water Management Model 5) was used for the continuous simulation of urban runoff. The analysis results of urbanization effect on runoff are as follows: the surface runoff in 2000 increases to 65% of the whole precipitation whereas the surface runoff in 1975 amounts to 50% of the precipitation; the groundwater runoff in 2000 amounts to 7% and shows 6% decrease during the period from 1975 to 2000.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.11 no.6
• /
• pp.1-10
• /
• 2008

The study was aimed at analyzing the relationship between the characteristics of urban green infrastructure and stormwater runoff in a small urban watershed composed of 22 drainage basins. The green areas of which soils are not sealed and allow water infiltrate, were examined for different types of green spaces. In a comparative study for drainage basins of which green spaces are 15.5% and 34.4%, respectively, runoffs were not different with the size of green space. It was attributed to that the increase of runoff by greater road area offset the advantage of greater green area. Another comparative measurement of runoff for drainage basins with similar green area size showed that runoff decreased with greater permeable area (school ground area) and smaller road area. The runoff measurements could address that runoff rates are affected not only by green area size but also by the type of green area and other land covers related to permeability and flow into drainage. It implicated that the improvement of urban green infrastructure as a functional unit for water infiltration and interception is important for stormwater runoff management.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.204-208
• /
• 2006

This study is to develop a distributed urban flood runoff model that simulates the road runoff and to test the applicability of the model by applying to Pyeongtaek city of $12.2km^2$. To generate the runoff along the runoff, agree burned DEM (Digital Elevation Model) with road networks was suggested and the proper spatial resolution of DEM was identified finer than 15 m. To test the model applicability, 32 points on the road networks were selected and the hydrographs of each point were generated. The test showed reasonable results that increase the road runoff from the high elevation roads to the low elevation roads and the road runoff considering rainwater drainage from the road also showed reasonable results.

• International Journal of High-Rise Buildings
• /
• v.3 no.4
• /
• pp.273-278
• /
• 2014

Green roof's performance in reducing stormwater runoff has been reported by numerous studies. Nonetheless, the roles of low growing vegetation in influencing stormwater runoff reduction on green roofs have been greatly overlooked. This paper describes an experiment investigating the influence of low growing vegetation in the reduction of tropical stormwater runoff on extensive green roofs. Three types of locally occurring native vegetation and one non-native Sedum species were selected (fern, herb, grass and succulent) for the experiment. Stormwater runoff reduction performance from different low growing species was done by measuring excess water runoff from the simulated green roof modules. The results show significant differences in stormwater runoff reduction from different types of vegetation. Fern was the most effective in reducing stormwater runoff, followed by herb, Sedum and grass. Vegetative characters that are found to attribute towards the performance of stormwater runoff are rooting density, structure, density, leaf type, and vegetation biomass.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.862-866
• /
• 2005

For urban watershed models, the ILLUDAS and SWMM are the popular rainfall-runoff models used in Korea. However, combined sewage systems in urban areas produced problems when a flood occured because of the surcharged precipitation amount which drained to the streams directly. Also, the lack of pipe line data and the difficulties of modeling yield inappropriate modeling results in urban runoff analysis. In addition, rainfall-runoff models in urban areas which use channel routing could have inaccurate and complicated processes. In this paper, the MIKE SWMM model has been applied for the stable runoff analysis of urban areas. Watershed and pipe line data were established by using past inundated records, DEM data, and the numerical pipe line data. For runoff modelings, the runoff block was adapted to a basin and the Extran block using dynamic equations was applied to the sewage system. After comparing to models that exist, it is concluded that the MIKE SWMM model produces reliable and consistence results without distorting the Parameters of the model.

• Journal of Korea Water Resources Association
• /
• v.38 no.11
• /
• pp.907-916
• /
• 2005

For an urban watershed modeling, the ILLVDAS and SWMM model were the popular rainfall-runoff models using in Korea. However, combined sewerage systems in urban area produce some problems when a flood event happens because of the surcharged precipitation amounts which drain to streams directly. Also, rack of pipe line data and difficulties of modeling yield inappropriate modeling results in urban runoff analysis. In addition, rainfall-runoff models in an urban which using channel routing could be inaccurate and complicated processes. In this paper, the MIKE SWMM model has been applied for a stable urban area runoff analysis. Watershed and pipe line data were established by using past inundated records, DEM data and numerical pipe line data. For a runoff modeling, the Runoff block was adapted to a basin and the Extran block using dynamic equation was applied for sewerage system. After a comparisons against existing models yield that the MIKE SWMM model produce reliable and consistence results without distorting parameter of the model.

• Journal of Korea Water Resources Association
• /
• v.36 no.5
• /
• pp.725-740
• /
• 2003

Urbanization concerned with concentration of population, activity and expanding the urban changes a natural environmental, and human activity in urban area causes the appearance of a new hydrologic cycle system. This study is carried out the analysis for the characteristics of runoff variation in urban areas with progress of urbanization. To simulate the mechanics of runoffs on small urban watershed, the ILLUDAS model is used in this study. From the analysis of the urban-runoff processes in small urban area with the progress of urbanization, the following conclusions is obtained. It is found in the results of calculated geographical parameter that peak time is quickened by 15∼35 minutes rather than the urbanization before. Also, in the analysis of the peak rate of runoff, the peak flow rise by 60 % than the urbanization before.

• KIEAE Journal
• /
• v.14 no.3
• /
• pp.15-21
• /
• 2014

In this study, we developed a modular rainwater infiltration system that can be applied for general purposes in urban areas to prepare for localized heavy rain caused by climatic change. This study also analyzed the system's effects on reducing runoff. An analysis of the system's effects on reducing runoff based on rainfall data and monitoring data obtained between September 2012 and December 2013 after the system was installed showed that approximately 20~22% of the runoff overflowed from the infiltration facility. Also, an analysis of the runoff that occurred during the monsoon season showed that 25% of the runoff overflowed through the storm sewer system of the urban area. These results show that the rainwater overflows after infiltrating the detention facility installed in the area during high-intensity rainfall of 100mm or higher or when precipitation is 100mm for 3~4 days without the prior rainfall. According to precipitation forecasts, torrential rainfall is becoming increasingly prevalent in Korea which is increasing the risk of floods. Therefore, the standards for storm sewer systems should be raised when planning and redeveloping urban areas, and not only should centralized facilities including sewer systems and rainwater pump facilities be increased, but a comprehensive plan should also be established for the water cycle of urban areas. This study indicates that decentralized rainwater management can be effective in an urban area and also indicates that the extended application of rainwater infiltration systems can offer eco-friendly urban development.

• Advances in environmental research
• /
• v.2 no.2
• /
• pp.99-118
• /
• 2013

Rainwater runoff has been identified as a significant source of contaminants having tremendous impact on the receiving aquatic environment. In the present study, trace element transport by the surface runoff in the predominantly urban catchment of Guwahati city, India was monitored with a view to determine the chemical denudation rates of the land surface. A number of trace metals, namely Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were measured in the runoff after 70 major rain events within the city. Cadmium was found to be the least abundant metal and Iron was the most abundant metal in the runoff. The results are interpreted on the basis of temporal and spatial variations in their concentrations. These variations are quite large in some of the events and reflect changes in the local environmental setting, differences in water utilization, variations in runoff volume, gradient and quality.