• Journal of Environmental Science International
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• v.25 no.1
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• pp.31-40
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• 2016

The purpose of this study was to analyse the runoff characteristics of non-point pollution sources in an urban watershed and determine the effectiveness of newly installed riverwater treatment system to reduce water pollution caused by storm runoff in the urban watershed. The results of this study showed that the levels of BOD5 and suspended solid were highly influenced by first-flush effect and the pollutant load of those two parameters were also very high in the urban watershed. Meanwhile, the effectiveness of riverwater treatment system to reduce the levels of BOD5 and suspended solid was relatively high, but those to reduce the levels of T-N and T-P was low, which needs some additional unit treatment process such as filtration and coagulation. Nonetheless, the riverwater treatment system tested was relatively simple in installation and operation, effective in removing many water pollutants and, most importantly, does not require much space as other treatment systems, so it could be an attractive alternative option to reduce riverwater pollution caused by storm runoff in urban watersheds.

• Journal of Korea Water Resources Association
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• v.39 no.11 s.172
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• pp.915-922
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• 2006

National Emergency Management Agency is planning a flood disaster mitigation system in urban area. This research is about analysis of runoff reduction efficiency of the alloted detention system which is one of flood disaster mitigation systems in urban area. The alloted detention system is composed of small to middle size detention facilities located in up and middle stream of urban basin. To analyze runoff reduction efficiency of alloted detention system, basic runoff analysis in test area has been carried out and runoff characteristics with size and locations of detention facilities has been simulated. The results of simulation are showing that alloted detention system can reduce the discharge of main stream and detention facilities' size and locations are major parameters of runoff reduction efficiency. It is concluded that alloted detention system can be a useful method in urban area's flood disaster mitigation and can secure safety against flood damages in urban areas.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.54-55
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• 2015

Increase of impervious areas due to expansion of housing area, commercial and business building of urban is resulting in property change of stormwater runoff. Also, rapid urbanization and heavy rain due to climate change lead to urban flood and debris flow damage. In 2010 and 2011, Seoul had experienced shocking flooding damages by heavy rain. All these have led to increased interest in applying LID and decentralized rainwater management as a means of urban hydrologic cycle restoration and Natural Disaster Prevention such as flooding and so on. Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Low Impact Development (LID) methods is to mimic the predevelopment site hydrology by using site design techniques that store, infiltrate, evaporate, detain runoff, and reduction flooding. Use of these techniques helps to reduce off-site runoff and ensure adequate groundwater recharge. The contents of this paper include a hydrologic analysis on a site and an evaluation of flooding reduction effect of LID practice facilities planned on the site. The region of this Case study is LID Rainwater Management Demonstration District in A-new town and P-new town, Korea. LID Practice facilities were designed on the area of rainwater management demonstration district in new town. We performed analysis of reduction effect about flood discharge. SWMM5 has been developed as a model to analyze the hydrologic impacts of LID facilities. For this study, we used weather data for around 38 years from January 1973 to August 2014 collected from the new town City Observatory near the district. Using the weather data, we performed continuous simulation of urban runoff in order to analyze impacts on the Stream from the development of the district and the installation of LID facilities. This is a new approach to stormwater management system which is different from existing end-of-pipe type management system. We suggest that LID should be discussed as a efficient method of urban disasters and climate change control in future land use, sewer and stormwater management planning.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.67-75
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• 2005

The objectives of this study were to understand the runoff characteristics of the non-point sources originating from impervious surfaces and to assess their effect on the aquatic environment in the urban areas. The concentration of pollutants (SS, BOD, COD and T-P) except for T-N showed the highest value in runoff from road, and event mean concentration (EMC) also showed high value from road. The pollutants discharged from road showed a higher concentration in the beginning stage (0 ${\sim}$ 30%) of progressive percentage of rainfall. The contribution percentages of non-point sources by load were 44.9% for SS, 11.2% for BOD, 21.4% for COD, 11.4% for T-N and 8.1% for T-P in the total load of pollutant discharged through sewer. From our results, the road was a significant potential source that deteriorated water quality of the streams and lakes in the vicinity of the urban area during the rain period. Therefore, counter plan is required to reduce pollutant concentration on the road from non-point sources in the urban area. Also, since pollutant concentration in the beginning stage of rainfall was quite high, road cleaning seems to be one of the very useful methods to prevent inflowing of pollutants to the aquatic environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5330-5336
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• 2011

It becomes more and more important to develop various infiltration facilities for healthy water cycle and reduction of urban storm water runoff. In this study, a infiltration facility by utilizing tree box was developed. The developed facility is capable of reducing storm water road runoff, improving urban water cycle, and performing other sustainable and environmental functions. Because the facility can be manufactured to a smaller size than an existing runoff reduction facility, it can be installed at various road types of not only existing urban areas, but new developed areas. If the facility is applied to four-lane roadways, it is expected to reduce 65% of rainfall runoff discharge. Urban flood control improvement can be accomplished by a wide application of the developed technique.

• Journal of Korea Water Resources Association
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• v.35 no.5
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• pp.611-618
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• 2002

In order to investigate the performance of the infiltration collector well and its effect on the runoff reduction, real-time field measurements are carried out. Based on these field data measured at Seongnam, Osan and Cheongju sites, the runoff reduction volumes and the peaks-cut-rate are quantitatively analyzed and compared with the total rainfall amount, the 10min averaged and the 10min maximum rainfall intensity. This results show that the infiltration collector well is very effective to reduce the runoff in urban area, which gives environmentally the positive to supply ground waters. It is also presented that the infiltration collector well is able to reduce up to 70% of the runoff and 40~70% of peaks, compared to a general one.

• Journal of Environmental Science International
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• v.24 no.8
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• pp.1065-1073
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• 2015

Urbanization can be significantly affected the hydrologic cycle by increasing flood discharge and heat flux. In order to mitigate these modifications in urban areas, Low Impact Development (LID) technique has been designed and applied in Korea. In order to estimate runoff reduction rate using SWMM LID model, the characteristics of five LID techniques was firstly analyzed for water balance. Vegetated swale and green roof were not reduce flood discharge nor infiltration amount. On the other hand, porous pavement and infiltration trench were captured by infiltration function. The flood reduction rate with LID is substantially affected by their structures and properties, e.g., the percentage of the area installed with LID components and the percentage of the drainage area of the LID components.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.479-486
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• 2010

Reliable hydrologic data acquisition is the basic and essential requirement for efficient water management. Especially the acquisition of various stream data in a certain location is very important to construct on alarm system to response an urban flood which occurs frequently due to the effect of climate change. Although the frequency of stream inundation flood occurrence becomes low owing to the consistent stream improvement, the urban flood due to the drainage system problems such as deterioration and bad management occurs continuously. The consistent management and current status understanding of the urban drainage system is essential to reduce the urban flood. The purpose of this study is to develop the urban runoff network flow velocity monitoring system which has the capability of collecting stream data whenever, wherever and to whomever without expert knowledge using Code Division Multiple Access technique and Bluetooth near-distance wireless communication technique. The urban runoff network flow velocity monitoring system consists of three stages. In the first stage, the stream information obtained by using ubiquitous floater is transferred to the server computer. In the second stage, the current state of the urban drainage system is assessed through the server computer. In the last stage, the information is provided to the user through a GUI. As a result of applying, the developed urban runoff network flow velocity monitoring system to Woncheon-Stream in Suwon, the information necessary for urban drainage management can be managed in real time.

• Journal of Korea Water Resources Association
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• v.50 no.5
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• pp.347-358
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• 2017

This study examined characteristic differences by the rainfall direction on the runoff responses. The directional characteristics of hydrological components in a basin were quantified by von Mises distribution. The runoff hydrograph was derived using the result of convolution integration of each distribution and this hydrograph was compared with GIUH model and observed data. As a result, it was found that runoff response by rainfall direction was more similar the observed rainfall-runoff data than the runoff result using GIUH model. These results implies that runoff modeling could be improved by considering directional components in hydrologic analysis. This study would be helpful to reduce uncertainties of hydrologic analysis considering a non-linearity of rainfall-runoff process by the rainfall direction.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.3
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• pp.13-26
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• 2015

Many urban areas in Korea suffer from repeated flood damage during intensive rainfall due to an increase in impervious areas caused by rapid urbanization and deteriorating sewage systems. A centralized stormwater management system has caused severe flood damage in an area that has proven unable to accommodate recent climate change and a rise in precipitation. Most flooding prevention projects that have been recently implemented focus on increasing drainage system capacity by expanding the size of sewer pipes and adding pumping stations in downstream areas. However, such measures fail to provide sustainable solutions since they cannot solve fundamental problems to reduce surface runoff caused by urbanization across the watershed. A decentralized stormwater management system is needed that can minimize surface runoff and maximize localized retention capacity, while maintaining the existing drainage systems. This study proposes a stormwater management corridor for the flood-prone watershed in the city of Dongducheon. The corridor would connect the upstream, midstream, and downstream zones using various methods for reducing stormwater runoff. The research analyzed surface runoff patterns generated across the watershed using the Modified Rational Method considering the natural topography, land cover, and soil characteristics of each sub-watershed, as well as the urban fabric and land use. The expected effects of the design were verified by the retainable volume of stormwater runoff as based on the design application. The results suggest that an open space network serve as an urban green infrastructure, potentially expanding the functional and scenic values of the landscape. This method is more sustainable and effective than an engineering-based one, and can be applied to sustainable planning and management in flood-prone urban areas.