• 수도
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• s.23
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• pp.9-15
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• 1980

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.191-199
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• 2012

Rainwater harvesting systems (RWHS), one of measures for on site rainwater management, have been promoted by laws, regulations and guidelines and have been increased. However, more evaluation of economic feasibility on RWHS is still needed due to seasonal imbalance of rainfall and little experiences and analysis on design and operation of RWHS. In this study, we investigated tank capacity of RWHS to secure economic validity considering catchment area and water demand, which is affected by building scale. Moreover, sensitivity analysis was performed to examine the effect of design factors, cost items and increase rate of water service charge on economic feasibility. The BCR (benefit cost ratio) is proportional to the increase in tank capacity. It is increased steeply in small tank capacity due to the effect of cost and, since then, gently in middle and large tank capacity. In case of 0.05 in the rate of tank volume to catchment area and 0.005 in water demand to catchment area, BCR was over one from the tank capacity of 160 $m^{3}$ taking into account of private benefits and from the tank capacity of 100 $m^{3}$ taking into account of private and public benefits. Sensitivity analysis shows that increase of water demand can improve BCR values with little cost so that it is needed to extend application of rainwater use and select a proper range of design factor. Decrease of construction and maintenance cost reduced the tank volume to secure economic validity. Finally, increase rate of water service charge had considerable impact on economic feasibility.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.5
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• pp.151-158
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• 2007

After installing calibrated depth scale at 11 different points inside the nine streams network for estimating time of concentration of stream in Young-Heung island near coastal region of Incheon we estimated the flow against actual rainfall events. By considering time of concentration formula which here mainly used for estimating the time of concentration from practical experiments, compared were three methods of inflow time and accepted to method of used the chart. The maximum flow occurrence time was estimated by an outflow model and observed maximum flow occurrence time were determined by to a comparative analysis. Kirpich formula was selected as the proper formula for calculating the concentration time inside the island streams. Kirpich formula could be applicable for the expanded range while catchment area of $0.453km^2$ and channel bed slope of $3{\sim}5%$ to catchment area of $2.0km^2$ and channel bed slope of about 1.5%.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.131-144
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• 1980

The Linear Regression Model to extend the monthly runoff data in the short-recorded river was proposed by the author in 1979. Here in this study generalization precedure is made to apply that model to any given river basin and to any given station. Lengthier monthly runoff data generated by this generalized model would be useful for water resources assessment and waterworks planning. The results are as follows. 1. This Linear Regression Model which is a transformed water-balance equation attempts to represent the physical properties of the parameters and the time and space varient system in catchment response lumpedly, qualitatively and deductively through the regression coefficients as component grey box, whereas deterministic model deals the foregoings distributedly, quantitatively and inductively through all the integrated processes in the catchment response. This Linear Regression Model would be termed "Statistically deterministic model". 2. Linear regression equations are obtained at four hydrostation in Geum-river basin. Significance test of equations is carried out according to the statistical criterion and shows "Highly" It is recognized th at the regression coefficients of each parameter vary regularly with catchment area increase. Those are: The larger the catchment area, the bigger the loss of precipitation due to interception and detention storage in crease. The larger the catchment area, the bigger the release of baseflow due to catchment slope decrease and storage capacity increase. The larger the catchment area, the bigger the loss of evapotranspiration due to more naked coverage and soil properties. These facts coincide well with hydrological commonsenses. 3. Generalized diagram of regression coefficients is made to follow those commonsenses. By this diagram, Linear Regression Model would be set up for a given river basin and for a given station (Fig.10).

• The Journal of Engineering Geology
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• v.4 no.2
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• pp.153-168
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• 1994

The status of groundwater development in Chungnam was studied with geological characteristics according to the measured data of Korean Rural Development Corporation. The data of 212 survey wells were used for the relation between catchment area and water discharge, and the data of 344 development wells for the relationships between well depth and discharge, between casing depth and discharge, between rock type and discharge, and the relation with lineaments density. The relationship between the catchment area and discharge does not show any special trend, and it is understood that groundwater of hard rock mass is not so much influenced by the surface catchment area. The relationship between well depth and discharge shows two different trends; discharge increasing with depth for alluvial groundwater, but no certain trend between depth and discharge for groundwater of hard rock zone. Discharge increases linearly with the casing depth, and it is reliable because the casing was installed in the weathered zone against well destruction. Generally the rock type does not show any difference of discharge, but the crystalline rocks such as granite and gneiss yield a little more discharge than the more porous rocks such as sedimentary rock or schist. It suggests that the effect of fracture zone is a major governing factor. In Hongsong and Puyo, there are similar in rock type and casing depth, but the big difference in average discharge. The big discharge of Hongsong is concordant with the higher intersection density and longer length of lineament in Hongsong than those of Puyo. Therefore the groundwater development strategy should be focused on the micro topography analysis and geophysical survey for the understanding of the fracture zone rather than catchment area or rock type.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.739-746
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• 1999

Discharge characteristics of organic materials and nutrients were estimated in the catchment area of relaimed area-Saemankeum-. Discharge load of BOD5 was high in the domestic system, while nitrogen and phosphorous were discharged mainly from the livestock system and the land . Load was so dependent on the precipitation that it increased in the rainy season, particulary in nitrogen and phosphorus. Loads from nonpoint sources in this area were higher compared with others.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.3
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• pp.37-46
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• 2013

Similarity measure of catchments is essential for regionalization studies, which provide in depth analysis in hydrological response and flood estimations at ungauged catchments. However, this similarity measure is often biased to the selected catchments and is not clearly explained in hydrological sense. This study applied a type of hydrological similarity distance measure-Flood Estimation Handbook to 25 Geum River catchments, Korea. Three Catchment Characteristics, Area(A)-Annual precipitation(SAAR)-SCS Curve Number(CN), are used in Euclidian distance measures. Furthermore, six index of Flow Duration Curve are applied to clustering analysis of SPSS. The catchments' grouping of hydrological similarity measures suggests three groups (H1, H2 and H3) and the four catchments are not grouped in this study. The clustering analysis of FDC provides four Groups; F1, F2, F3 and F4. The six catchments (out of seven) of H1 are grouped in F1, while Sangyeogyo is grouped in F2. The four catchments (out of six) of H2 are also grouped in F2, while Cheongju and Guryong are grouped in F1. The catchments of H3 are categorized in F1. The authors examine the results (H1, H2 and H3) of similarity measure based on catchment physical descriptors with results (F1 and F2) of clustering based on catchment hydrological response. The results of hydrological similarity measures are supported by clustering analysis of FDC. This study shows a potential of hydrological catchment similarity measures in Korea.

• Journal of Korean Society on Water Environment
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• v.27 no.1
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• pp.9-18
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• 2011

In this study the optimal volume for non-point source control retention is estimated considering spatio-temporal variation of land surface. The 3-parameter mixed exponential probability density function is used to represent the statistical properties of rainfall events, and NRCS-CN method is applied as rainfall-runoff transformation. The catchment drainage area is divided into individual $30m{\times}30m$ cells, and runoff curve number is estimated at each cell. Using the derived probability density function theory, the stormwater probability density function at each cell is derived from the rainfall probability density function and NRCS-CN rainfall-runoff transformation. Considering the antecedent soil moisture condition at each cell and the spatial variation of CN value at the whole catchment drainage area, the ensemble stormwater capture curve is established to estimate the optimal volume for an non-point source control retention. The comparison between spatio-temporally varied land surface and constant land surface is presented as a case study for a urban drainage area.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.905-918
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• 2023

This study aimed to assess runoff reduction performance and determine installation priorities for Permeable Pavement (PP) and Rain Barrel (RB) within the Mokgam Stream basin. Optimal design parameters were determined to maximize the effectiveness of PP and RB in reducing runoff. Furthermore, the optimal parameters were incorporated to compare the runoff reduction performance of PP and RB. Analysis of the runoff curve at the basin outlet indicated that PP demonstrated superior performance in reducing runoff during the rising limb of the curve. At the same time, RB excelled within the falling limb. Comparisons of total runoff and peak runoff reduction by sub-catchment revealed that in larger sub-catchment areas, PP outperformed RB in runoff reduction. In contrast, RB exhibited higher performance in areas with a higher impervious ratio. Based on the evaluation of runoff reduction performance for PP and RB, installation priorities were determined within the Mokgam Stream basin. The results showed that PP and RB installations were prioritized for sub-catchments with larger areas and a higher impervious ratio. Furthermore, the correlation between the ranking of runoff reduction performance and sub-catchment characteristics showed a high correlation with both the impervious area ratio and sub-catchment geometrical properties in sub-watersheds exhibiting the top 25% runoff reduction performance. These results emphasize that when determining the priority for installing LID facilities in developed urban areas, it is necessary to consider not only the impervious area ratio but also the geometrical properties of the sub-catchment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.341-351
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• 2015

This study is to select the areas to ensure stream space or to implement flood defence measures according to flood frequencies by classifying the stream segment using river bed slope in Mangyeong river. The analysis result for each stream segment showed that the variation of flood inundation area was small in upper stream catchment. But in the lower stream area, the inundation area became larger greatly according to the increase of flood return period. This study classified the catchment of each steam segment as the region of ensuring stream space (ESS), below 10% residential area ratio, and the region of reinforcing flood defence (RFD), over 10% residential area ratio. The analysis results showed that the lower stream area included more RFD regions than upper stream area, and the upper stream area included more ESS regions than lower stream area. In future study, the regions stream spaces can be ensured will be analyzed considering the past stream morphology and the positions of wetlands.