• Water for future
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• v.28 no.3
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• pp.159-173
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• 1995

This study is to develop the suitable hydrologic models for determination of the size and location of detention storage facilities to restrain stormwater runoff in urban areas. Fictitious areas of two levels are considered to seize the hydrologic response characteristics. A one-square-kilometer area is selected for the catchment level, and a 10-square-kilometer area consisting of 10 catchments is adapted at the watershed level as representative of urban drainage area. In this analysis, different rainfall frequencies, land uses, drainage patterns, basin shapes and detention storage policies are considered. Flow reduction effect of detention storage facilities is deduced from storage ratio and detention basin factor. A substantial saving in detention storage volumes is achieved when the detention storage is planned at the watershed level than the catchment level. For the application of real watersheds, two watersheds in Seoul metropolitan area-Jamshil 2, Seongnae 1-are selected on the basis of hydrologic response characteristics. Through the regression analysis between dimensionless detention storage volume, dimensionless upstream area ratio and reduction rate of storage ratio, the regression equations to determine the size and location of detention storage facilities are presented.

• Journal of the Korean GEO-environmental Society
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• v.20 no.2
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• pp.5-18
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• 2019

In this study, it was conducted a broad-area landslide analysis for the entire area of Kyungsangbuk-do Province based on spatially-distributed wetness index and root reinforcement infinity slope stability theory. Specifically, digital map, soil map and forest map were used to extract topological and geological parameters, and to build spatially-distributed database at $10m{\times}10m$ resolution. Infinity flow direction method was used for rain catchment area to produce spatially-distributed wetness index. The safety level that indicates risk of a broad-area landslide was classified into four groups. The result showed that areas with a high estimated risk of a landslide coincided with areas that recently went through an actual landslide, including Bonghwa and Gimcheon, and unstable areas were clustered around mountainous areas. A comparison between the estimation result and the records of actual landslide showed that the analysis model is effective for estimating a risk of a broad-area landslide based on accumulation of reasonable parameters.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.983-989
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• 2018

The real-time monitoring of surface vegetation is essential for the management of droughts, vegetation growth, and water resources. The availability of land cover maps based on remotely collected data makes the monitoring of surface vegetation easier. The vegetation index in an area is likely to be proportional to meteorological elements there such as air temperature and precipitation. This study investigated relationship between vegetation index based on Moderate Resolution Image Spectroradiometer (MODIS) and ground-measured meteorological elements at the Yongdam catchment station. To do this, 16-day averaged data were used. It was found that the vegetation index is well correlated to air temperature but poorly correlated to precipitation. The study provides some intuition and guidelines for the study of the droughts and ecologies in the future.

• Journal of the Korean housing association
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• v.25 no.3
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• pp.53-62
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• 2014

This paper investigates whether the use of Rainwater Harvesting Systems (RWHSs) to provide water for washing machines in Hong Kong residential buildings would be financially attractive. In such systems, rainwater is accumulated and reused for doing laundry, garden irrigation, flushing toilets, and even drinking. Thus, the analysis of RWHSs' financial feasibility is essential for construction projects. RainCycle is used to validate financial feasibility, considering particular circumstances and data relevant to the Hong Kong context. A range of different scenarios by adjusting three factors are evaluated: catchment area, water demand, and discount rate. It is suggested that $2,000m^2$ would be a suitable catchment area in a typical Hong Kong residential building and it is demonstrated how water demand and discount rate influence the financial performance of RWHSs. In particular, the financial performance of RWHSs is sensitive to discount rates. The results suggest that the RWH system would be worthwhile for buildings with a lower number of floors, but would barely achieve financial validation in Hong Kong's super high-rise residential buildings.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.197-206
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• 2013

Recently, climate change causes climatic anomaly such as global warming, the typhoon and severe rain storm etc. and it brings damage frequently. Climate change and global warming are prevalent all over the world in this century and many researchers including hydrologists have studied on the climate change. In this study, Seonakdong river watershed in the Nakdong river basin was selected as a study area. Real-time monitoring system was used to draw the rating curves, which has 0.78 to 0.96 of $R^2$. To predict runoff change in Seonakdong river watershed caused by climate change, the change in hydrologic runoff were predicted using the watershed model, SWAT. As a result, the runoff from the Seonakdong river watershed was increased by up to 45 % in summer. Because of the non-point sources from the farmland and the urban area, the water quality will be affected by the climate change. In this study, the operating plan of the water gates in Seonakdong river will be suggested by considering the characteristics of the watershed runoff due to the climate change. The optimal watergate opening plan will solve the water pollution problems in the reservoir-like river.

• Proceedings of the Korea Water Resources Association Conference
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• 1990.07a
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• pp.19-19
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• 1990

The paper presents the development and applications of physically-based urban runoff analysis model, URAM, which is capable of simulating sewer runoff hydrographs and inundation conditions within a small urban catchment. The model considers three typical flow conditions of urban drainage networks, whichn are overland flow, gutter flow, and conduit flow during a storm. Infiltration, retention storage and flow routing procedures are physically depicted in model. It was tested satisfactorily with field data from a tested catchment having drainage area of 4.91 ha. It was also applied to other urban areas and found to adequately simulate inundation areas and duration as observed during storms. The test results as well as model components are described in the paper.

• Water for future
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• v.23 no.3
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• pp.329-340
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• 1990

The Paper presents the development and applications of physically-based urban runoff analysis model, URAM, which is capable of simulating sewer runoff hydrograhps and inundation conditions within a samll urban catchment. The model coniders three typical flow conditions of urban drainage networks, which are over-land flow, gutter flow, and conduit flow during a storm. Infiltration, retention storage and flow routing procedures are physically depicted in model. It was tested satisfactorily with the field data from a tested catchment having drainage area of 0.049k$m^2$. It was also applied to other urban areas and found to adequately simulate inundation areas and duration as observed during storms. The test results as well as model components are described in the paper.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.49-49
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• 2016

The impact of land cover changes on streamflow of the Akaki catchment will be assessed using Soil and Water Assessment Tool (SWAT) model. The study will analyze the historical land cover changes (1993 to 2016) that have taken place in the catchment and its effect on the streamflow of the study area. Arc GIS will be used to analysis the satellite images obtained from the United States Geological Survey (USGS). To investigate the impact of land cover change on streamflow the model set up will be done using readily available spatial and temporal data, and calibrated against measured discharge. Two third of the data will be used for model calibration (1993?2000) and the remaining one-third for model validation (2001?2004). Model performance will be evaluated by using Nash and Sutcliff efficiency (NS) and coefficient of determination (R2). The calibrated model will be used to assess two land cover change (2002 and 2016) scenarios and its likely impacts of land use changes on the runoff will be quantified. The evaluation of the model response to these changes on streamflow will be presented properly. The study will contribute a lot to understand land use and land cover change on streamflow. This enhances the ability of stakeholder to implement sound policies to minimize undesirable future impacts and management alternatives which have a significant role in future flood control of the study area.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.397-400
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• 2002

Discharge characteristics of pollutant loadings from sewage systems were estimated in the catchment area of a reclaimed area - Saemangeum -. Pollutant loadings were estismated according to the discharge pattern of small treatment facilities. BOD pollutant loadings produced by population were 84,380kg/day, which were composed of nightsoil 35% and sewage 65%.

• Korean Journal of Environment and Ecology
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• v.22 no.2
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• pp.128-137
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• 2008

The purpose of this study is to analyze the effect of hiking trails on forest landscape's fragmentation, based on which also to assess the landscape-ecology-based integrity by small drainage area by selecting Bukhansan National Park as a survey target. The results of effect analysis are as follow; size of forest patch decreased; the density of patch and edge increased; patch shape became complicated; the dimensions of core area noticeably decreased and proximity degree between patch increased after trail-building. In addotion, the assessment results of overall landscape ecology-based integrity by small drainage basin showed that the Bukhansan catchment area was highest making 3.7 point, while Gugi catchment area was rated the lowest making 1.6 point. Putting the above results together, it is necessary to prohibit the opening up of unnecessary trails and to make room for ecological restoration of damaged and disturbance area to their original state as nature goes for landscape-ecology-based conservation and management of forests.