• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.147-154
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• 2010

In this study, flood control effects for infiltration trench which is one of runoff reduction facilities were analyzed based on hydraulic experiments. Hydraulic experiments were conducted using 25 cm diameter circular pipe, and water depths for boundary conditions are 5, 10, 15, 20, 25 cm. Infiltration volume, runoff volume, runoff initiation time, final infiltration capacity and final infiltration capacity reached time etc. were measured from infiltration trench hydraulic experiment. We assumed that drainage area of each infiltration trench is $130\;m^2$ ($6.5\;m{\times}20\;m$) and calculated CN with area based on those experimental characteristics. In AMC-I condition, the calculated CN with five water depths is 84 for 2% pipe slope, 83 for 5% pipe slope. In AMC-III condition, the calculated CN is 84 for 2% and 5% pipe slope.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.49-52
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• 2008

New Orleans located in the estuary of the Mississippi River was attacked by Hurricane Katrina and suffered big flood on August 2005. Since unconsolidated Holocene to middle Miocene strata is the main basement rocks, land subsidence has been occurred steadily due to soil compaction and normal faulting. It was reported that the maximum subsidence rate from 2002 to 2005 was -29 mm/yr. Many studies in the area have been carried out for understanding the subsiding and potential risks caused by ground subsidence are weighted by the fact that a large area of the city is located below the mean sea level. A small baseline subset (SBAS) method is applied for effectively measuring time-series LOS (Line-of sight) surface deformation from differential synthetic aperture radar interferograms in this study. The time-series surface deformation at New Orleans was measured from RADARSAT-1 SAR images. The used dataset consists of twenty-one RADARSAT-1 fine beam mode images on descending orbits from February 2005 to February 2007 and another twenty-one RADARSAT-1 standard beam mode images on ascending orbits from January 2005 to February 2007. From this dataset, 25 and 38 differential interferograms on descending and ascending orbits were constructed, respectively. The vertical and horizontal components of surface deformation were extracted from ascending and descending LOS surface deformations. The result from vertical component of surface deformation indicates that subsidence is not significant with a mean rate of -3.1${\pm}$3.2 mm/yr.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.78-84
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• 2015

In order to increase the utilization of limited space in urban area, it can be a good solution to make use of underground space. For the last few decades, underground space systems, such as underground passages, subway stations, and underground shopping arcades, have been constructed in many cities all over the country. Despite of the advantages on the utilization of space in urban area, underground space systems have always been exposed to the risk of inundations resulted from severe rain storms. In this study, it has been examined to apply 2-D flow models (TUFLOW and FLUMEN) to establishing the preventive measures to the risk of flood. For the part with relatively complex configuration, such as a corridor junction, 2-D flow models present the detailed information about the effect of geometry on the inundation events and the temporal and spatial distribution of inundation over the space. From the result, it can be concluded that the 2-D flow model can be the effective implement for establishing the proper measure to the inundation on underground space systems, which generally have relatively long and narrow geometry with complex inner configuration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.427-437
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• 2016

The objective of this study is to develop the regional regression models based on the physiographical and climatological characteristics for estimating flow duration curve (FDC) in ungauged bsisns. To this end, the lower sections with duration from 185 to 355 days of FDCs were constructed from the 16 gauged streamflow data, which were fitted to the two-parameter logarithmic type regression equation. Then, the parameters of the equation were regionalized using the basin characteristics such as basin area, basin slope, drainage density, mean annual precipitation, mean annual streamflow, runoff curve number in order that the proposed regression model can be used for ungauged basin. From the comparison of the estimated by the regional regression model with the observed ones, the model with the combination of basin area, runoff curve number, mean annual precipitation showed the best performance.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.135-144
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• 2017

The riverbed areas have exposed to various natural disasters and the private use by neighboring residents have caused many problems. The research objectives are to survey the actual situation of riverbed areas in order to prevent landscape damage and private use. Drone and photogrammetry, orthophoto, DSM(Digital Surface Model), digital topographic map and cadastral information have been integrated by GIS technology. The flood and disaster vulnerable area has been surveyed and the land use and private use has been analyzed using cadastral information. The research results show that the analyzed data can be used for providing foundation data for management of river and also can be used for surveying actual situation of private use on the riverbed areas.

• Ocean and Polar Research
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• v.28 no.3
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• pp.339-352
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• 2006

Seasonal and tidal variations of density stratification in the Saemangeum waters are investigated based on synoptic CTD observations between July 2003 and September 2005. CTD data used in this study are those obtained after closing the dike No. 4 and before closing the two final gaps, the Sinsi and the Garyeok, on the Saemangeum tidal harrier. A total of 19 field campaigns comprehend a wide temporal spectrum, that is, few seasons, spring and neap tides, and high and low waters. In addition, ADCPs were anchored and CTDs were cast at three stations for 25 h in July 2005. Water columns are vertically homogeneous in autumn and winter. The vertical homogeneity persists in spring but with an occasional weak stratification in i:he northern part of the Gogunsan Islands. Increased reshwater runoff tends to stabilize the water columns and strong density stratification is established in summer. The mean potential energy anomaly (PEA) in summer used as a stratification parameter is the largest $(27.7\;J\;m^{-3})$ in the northern part of the Gogunsan Islands where the Geum River discharge dominates, the smallest $(16.9\;J\;m^{-3})$ is in the inner area of the barrier, in between the two $(21.6\;J\;m^{-3})$ in the southern part of the Gogunsan Islands. Whereas the stratification is generally strengthened in summer, strong winds or large tidal currents over the shallow depths frequently destratify the water column near the mouth of river runoff inside the tidal barrier. Periodic stratification, the development of stratification on the ebb and its breakdown on the flood, occurs in the mid-area inside the barrier induced by the tidal straining, which can also be found in the results of 25 h observation.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.51-60
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• 2004

Urban flood damage has been caused by drainage deficiency. One of the methods to solve this problem is to construct detention basin and Pumping station and to pump out the water to the river. However, because of rapid urbanization, the capacity of drainage pipelines is sometimes not sufficient enough during the rainy season. Therefore, even though we have enough pumping stations, the inflow of surface water never reaches to the detention area, causing floods in urban area. This research is to find improvement of urban drainage system, estimating drainage pipeline risk. Also, eight models for a computer program were developed for practical use. The models were verified changing precipitation duration, intensity, design period, time distribution model, and etc. This verification was processed focusing that the model can regulate the water level in the detention basin and minimize the effect downstream. As a result Fuzzy models were found to be efficient to lower the water level in detention basin, and decreased about 8 cm in water level of downstream.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.4
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• pp.255-262
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• 2012

Numerical simulations were performed to evaluate the dispersion characteristics of the pollutant around a Wolsung coastal area at located nuclear power plants. Numerical experiments by using EFDC(Environmental Fluid Dynamics Code) showed good agreements by comparison with the time series and harmonic analysis of the tidal elevations. The released pollutants moved in north direction at flood tide and in south direction at ebb tide. The calculated salinity and temperatures showed good agreements with the observed results by NFRDI(National Fisheries Research & Development Institute). The water circulation due to the variations of the temperature, salinity and tidal components were analyzed to estimate the dispersion characteristics of the pollutant.

• Journal of Korean Society of Disaster and Security
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• v.7 no.1
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• pp.17-25
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• 2014

Due to the recent climate change impact, natural disasters occur due to sea surface rising, typhoon attacks, flash floods, local heavy rainfalls, landslides, and coastal area erosion, continuing to cause human and property damage. These impacts, coupled with urbanization and industrialization activities, are turning the previously safe areas into disaster-vulnerable areas, increasing human and economic damage. This paper aimed to prepare measures designed to minimize human damage in natural disaster vulnerable parts of South Korea in summer. Toward that end, how vulnerable areas were managed and what the damage was like were studied. Also, cases of human damage and statistics there of were reviewed and analyzed, relevant problems were derived, and thus structural and non-structural measures designed to minimize human damage were presented.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.749-759
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• 2016

The aim of this study is to apply and to evaluate the radar-based risk prediction algorithm for damage reduction by sudden localized heavy rain in urban areas. The algorithm is combined with three processes such as "detection of cumulonimbus convective cells that can cause a sudden downpour", "automatic tracking of the detected convective cells", and "risk prediction by considering the possibility of sudden downpour". This algorithm was applied to rain events that people were marooned in small urban stream. As the results, the convective cells were detected through this algorithm in advance and it showed that it is possible to determine the risk of the phenomenon of developing into local heavy rain. When use this risk predicted results for flood prevention operation, it is able to secure the evacuation time in small streams and be able to reduce the casualties.