• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.1
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• pp.52-61
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• 2004

Korea Water Resources Corporation carried out LiDAR survey to construct detailed terrain data for flood mapping and it is expected that much money is required in flood mapping of all over the country. Therefore, it is desirable to use NGIS digital map to construct preliminary modelling data for selection of flood mapping area. And the analysis of DEM error with respect to scale of digital map is necessary for the sake of applying digital map as the input data of flood mapping. We compared DEM from digital map with DEM from LiDAR survey. Especially we analyzed DEM error characteristics that is occurred with respect to the interpolation method that is used to construct DEM from TIN of digital map. As a result of analysis, digital map(1:1,000) showed smaller error than digital map(1:5,000) and DEM applying linear interpolation showed smaller error than DEM applying quintic interpolation. Especially, variation of DEM error by cell resolution was evaluated as very slight because urban district was composed of gentle slope.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.1
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• pp.97-109
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• 2004

The disposal of stormwater is one of the major problems in urban water management. One method of reducing peak runoff rates and other detrimental impacts of stormwater is detention storage. Detention ponds as a water quality control alternatives have been investigated by a number of researchers. Recognizing multiple roles such as flood peak attenuation, pollution removal and aesthetic enhancement, the design and management of detentions ponds deserve more research. The purpose of this research is to establish design criteria wet detention ponds to improve water quality. Water quality in detention pond discharge might be improve with physical, chemical and biological alterations. Physical alteration was focused in this study. There are several methods for estimating the suspended solid control capability of wet detention ponds. Existing models of suspended solids removal are based on sedimentation and gravity settling theory. The pollutant trap efficiency of pond is a function of several interrelating factors. Detention time is the most important factor, because it determine gravity settling quantities of pollutants. Desirable modification of physical factors for improvement of water quality in wet detention ponds are volume ratio, area ratio, length to width ratio, depth, out let location, bottom soil type. In order to apply design procedure in actual site, Namak new town development area was selected.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.2
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• pp.62-73
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• 2001

The riparian environments of urban streams in Korea have been disturbed through the channelization for flood control and artificial land use as well as water pollution and flow decrease due to industrialization and urbanization. The flora and vegetation structure were investigated and an implication of stream restoration was discussed for the conservation of biodiversity in the riparian area of the Seunggi stream in Incheon. Naturalized plants and ruderal plants were widely distributed in the riparian area which was disturbed from cultivating, trampling, dumping etc. Submerged and floating hydrophytes were not found in the stream due to channelization and water pollution. Some halophytes were remained in downstream and reservoir after reclamation and embankment. The communities of Humulus japonicus, Panicum dichotomiflorum, Digitaria sanguinalis, Artemisia montana, Amaranthus retroflexus, and Aster pilosus were distributed in the disturbed area of bank slope and floodplain in the stream. As a natural potential vegetation, Phragmites australis in the wet meadow, Typha latifolia, Typha angustifolia, Oenanthe javanica, Persicaria thunbergii, and Penthorum chinense in the marsh, and Salix babylonica and Salix matsudana for. tortuosa in the woodland appeared in the floodplain. The topography in the stream played an important role on the distribution of riparian vegetation in the Seunggi stream. Appropriate methods for conservation and restoration of the riparian ecosystems must be planned on the basis of the actual vegetation in the disturbed urban stream.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.133-141
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• 2011

Urban development of basin causes increasing runoff volume and peak flowrate and shortening in time of concentration, which may cause frequent flooding downstream. An infiltration facilities are operated as a method of reducing flood discharge of urban rivers and peak flowrate. There are various types of infiltration facilities like infiltration trench and porous pavement. In this study, runoff reduction effect due to installation of infiltration facilities are performed and focused on $0.18km^2$ residential area of Ok-kye dong and $0.67km^2$ industrial area of Gong-dan dong in Gumi City. The analysis is fulfilled with comparison of total runoff volume and runoff reduction volume by using the WinSLAMM and the relation equation between area ratio of infiltration facilities and ratio of runoff reduction are derived and peak flow reduction effect for installation of infiltration facilities is analyzed.

• Journal of the Korean association of regional geographers
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• v.14 no.1
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• pp.1-18
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• 2008

If there is no choice but to be urbanized, we should examine how human interference has had influences on the area to keep the river environment safe and stable. This study is aimed at finding improvement by examining the effect of human interference in Gapcheon river in Daejeon, which is developing fast. Distinctive features of human interference in Gapcheon river are followings. First, middle and upper reaches of Gapcheon river are being maintained and restored focusing on flood control but are scheduled to develop city and channel. Second, the rear area of middle and lower reaches of Gapcheon river is already developed into an urban district and solidified into artificial stream for leisure activities installing the artificial structure for fun. Third, lower reaches of Gapcheon river are in an unstable condition because of straightening waterway and developing rear area of river. Up to now, geographical features and bio-diversity of Gapcheon river has been ruined by the artificial management of river centered for technical engineering. From now on, followings should be considered for management of urban river. First, it is focused on maintaining eco system by itself than usage for human. Second, natural features of rear area of river should be taken into consideration and should be preserved before developing urban city and hills, back marsh, channel deposit and swamp to directly have an influence on river.

• Journal of Korean Society of Disaster and Security
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• v.16 no.1
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• pp.13-22
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• 2023

The importance of preemptive flood preparation is growing as the importance of preparing for climate change increases due to record heavy rains in the Seoul metropolitan area in August 2022. Although it is responding to flood control through reservoirs and sediment sites, the government is preparing excellent spill reduction measures through a preliminary consultation system for Low Impact Development (LID). In this study, the depth of flooding was simulated when LID technologies were applied to the Sillim 2-drain region in Dorimcheon Stream basin, an urban stream, using XP-SWMM, a two-dimensional model. In addition, the analysis and applicability of the effect of reducing rainfall runoff for the largest rainfall in a day were reviewed, and it was judged to be effective as a method of reducing flooding in urban areas. Although there is a limitation in which the reduction effect is overestimated, it is thought that the LID technologies can be a significant countermeasure as a countermeasure for small-scale flooded areas where some flooding occurs after structural flooding measures are established.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.141-150
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• 1992

Rapid change of urban area become a serious cause of disaster in existing drainage systems, and the practical alternatives in that situations are needed. The purpose of this study is to evaluate safety, one of drainage systems, detention reservoir and pumping station by new pumping criteria. New drainage pumping criteria, divided into two parts (rising limb and falling limb), which used in reservoir routing, shows more efficient flood prevention effect than existing criteria (based on the reservoir water level). To obtain the optimal range of flood prevention, sensitivity analysis of each inflow v.s. pumping capacity is tested. As a results, using 10 year design rainfall, 60% of detention reservoir and drainage pumping stations in Seoul are safe. In this results, there must be a fundamental and powerful counterplans to prevent inland flooding in Seoul metropolitan area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.395-406
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• 2018

The XP-SWMM model, widely used for inundation analysis of urban watersheds, underestimated the inundation area (range) because the manhole was regarded as a node and the influence of the local loss occurring in the surcharged manhole can not be considered. Therefore, it is necessary to analyze the applicability of the head loss coefficients considering the local loss in the surcharged manholes in inundation analysis using XP-SWMM. The Dorim 1 drainage section of the Dorim-river watershed, where frequent domestic flood damage occurred, was selected as the study watershed. The head loss coefficients of the surcharged manholes estimated from the previous experimental studies were applied to the inundation analysis, and the changes of the inundation area with and without the application of the head loss coefficients with manhole types were compared and analyzed. As a result of inundation simulation with the application of head loss coefficients, the matching rates were increased by 17% in comparison with the without application of them. In addition, the simulated inundation area applied only the head loss coefficients of straight path manholes and applied up to the head loss coefficients of combining manholes ($90^{\circ}$ bend, 3-way, and 4-way) were similar. Therefore, in order to accurately simulate the storm drain system in urban areas, it could be to carry out two-dimensional inundation analysis considering the head loss coefficients at the surcharged manholes. It was expected that the study results will be utilized as basic data for establishing the identification of the inundation risk area.

• Journal of Korea Water Resources Association
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• v.48 no.2
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• pp.105-114
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• 2015

In the case of rapidly developed urban and industrial complex, the most area becomes impervious, which causes the increasing runoff and high probability of flooding. SWMM model has been widely used to calculate stormwater runoff in urban areas, however, the model is limited to interpreting the actual natural phenomenon. It has the uncertainty in the model structure, so it is difficult to calculate the accurate runoff from the urban basin. In this study, the model parameters were investigated and uncertainty was quantified using Uncertainty Quantification Index (UQI). As a result, pipe roughness coefficient has the largest total uncertainty and largest effect on the total runoff. Therefore, when the stormwater pipe network is designed, pipe roughness coefficient has to be calibrated accurately. The quantified uncertainty should be considered in the runoff calculation. It is recommended to understand the characteristics of each parameter for the prevention and mitigation of urban flood.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.793-802
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• 2022

Non-structural improvements to urban drainage systems are necessary to overcome the elevated levels of urban flood damage. This study proposed a type of automatic pump/gate operation technology for urban pump stations that takes reservoir inflows and river water levels into account and its performance is compared with the current operation using the concept of residual flow-based resilience. The proposed automatic operation relies on three pump operations and two gate operations. The water depth at the monitoring node was used for the pump operation, and the monitoring node was selected in consideration of the first overflow node and the maximum overflow node. The target area is the Daegu Bisan urban pump station, and the rainfall data consisted of probability rainfall sets with durations of 30 minutes, 60 minutes, 90 minutes and 120 minutes, and frequencies of 30, 50, and 70 years. As a result of the application of the proposed operation, differences in the resilience between the automatic operation and the current operation were at least 5.20E-05 with a maximum of 8.07E-04. The longer the duration is, the greater the difference in the resilience.