• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.587-596
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• 2011

The interest in hydrological modeling has increased significantly recently due to the necessity of watershed management, specifically in regards to lumped models, which are being prosperously utilized because of their relatively uncomplicated algorithms which require less simulation time. However, lumped models require empirical coefficients for hydrological analyses, which do not take into consideration the heterogeneity of site-specific characteristics. To overcome such obstacles, a distributed model was offered as an alternative and the number of researches related to watershed management and distributed models has been steadily increasing in the recent years. Thus, in this study, the feasibility of a grid-based rainfall-runoff model was reviewed using the flood runoff process in the Han River basin, including the ChungjuDam, HoengseongDam and SoyangDam watersheds. Hydrological parameters based on GIS/RS were extracted from basic GIS data such as DEM, land cover, soil map and rainfall depth. The accuracy of the runoff analysis for the model application was evaluated using EFF, NRMSE and QER. The calculation results showed that there was a good agreement with the observed data. Besides the ungauged spatial characteristics in the SoyangDam watershed, EFF showed a good result of 0.859.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.6
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• pp.26-37
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• 2008

The purpose of the study was to evaluate the effect of pervious pavements on reducing the surface runoff caused by rainfall. The surface runoff from twelve steel experimental beds with different pavement had been recorded every minute from May to September 2008, by the measuring system of tipping buckets(0.1mm/count) and data aquisition systems(National Instrument's Labview and DAQ boards & Autonics PR12-4). The dimension of the experimental bed was $1.5m(W){\times}2.0m(L){\times}0.6m(D)$ and eleven different kinds of vegetational(grass, grass+cubic stone, grass+hole brick), modular(brick, cubic stone, small cubic stone, wood block, interlocking block, clay brick, granular clay brick) and granular(naked soil, gravel) paving materials and concrete were applied for the comparison. Six rain events with depth over 30mm were selected and compared. The maximum depth of the rainfall selected was 137.5mm for 28 hours, and the minimum 30mm for 5 hours. The maximum rainfall per hour was 23mm/hr and the minimum 11.4mm/hr. The major findings were as follows; 1. All pervious pavement applied reduced over 75% of the surface runoff compared with concrete pavement. The grassy and porous pavements were relatively efficient in reducing surface runoff. 2. The grass was the more efficient as intercepting average 69.5mm of initial surface runoff, and maximum 77.8mm at the condition of 13.5mm/hr rainfall. The next was gravel intercepting maximum 65.5mm at the condition of 13.5mm/hr and the 40.9mm at 19.1mm/hr, average 55.7mm. 3. The modular pavements common in urban area were not good in intercepting the runoff except the 'clay granular brick' compared with others. The 'clay granular brick' showed relatively efficient intercepting average 14.1mm, which was the bigger amount than the 'grass+hole brick'. 4. The 'naked soil' were more effective than the 'concrete', 'brick', and 'interlocking block' in reducing the surface runoff, but less efficient than other materials. The capacity of the 'naked soil' to intercept the initial rainfall was similar to the 'brick'. As summary, the more grassy and porous pavement shows more effective in reducing surface runoffs.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.2
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• pp.11-16
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• 2008

The effects of water and pesticide management practices on ponded water pesticide concentrations in a paddy plot were analysed using the RICEWQ model. The molinate which is a herbicide widely used in rice culture, and frequently detected in paddy environment was selected. In a previous study, the RICEWQ model was successfully calibrated with field data obtained from a paddy plot in Daegu. The calibrated model was run using water and pesticide management scenarios with a set of measured meteorological data for 1997-2006 in Daegu. For all three ponded water depths with the label rate application, the amount of molinate dissipated in ponded water and volatilized accounted for more than 70%, and the runoff losses were less than 9%. The molinate losses through drainage in the very shallow ponded depth showed 40% less than that in deep ponded depth. Comparing with the deep and shallow ponded depth, the very shallow depth was the best with regards to the reduction of molinate runoff losses. Simulations with different pesticide application rates, label rate and double label rate, showed molinate concentrations in the ponded water increased linearly with the application rate increase.

• Journal of Korean Society on Water Environment
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• v.32 no.6
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• pp.562-569
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• 2016

Recently, Low Impact Development (LID) is being used in Korea to control urban runoff and nonpoint source pollution. In this study, we evaluated the reduction of surface runoff from a study area, as the effect of connecting three bioretention as LID-BMP. Surface runoff and storage volume of bioretention is estimated by the Curve Number (CN) method. In this study, the storage volume of bioretention is divided by the volume of surface runoff and precipitation which directly enters the bioretention. The ratio of captured surface runoff volume to storage volume is highly influenced by the ratio of drainage area to surface area of bioretention. The high bioretention surface area-to-drainage area ratio captures more surface runoff. The ratio of 1.2 captures 51~54% of the total surface runoff, ranging from 5-30cm of bioretention depth; a ratio of 6.2 captures 81~85%. Three connected bioretentions could therefore captures much more runoff volume, ranging from $35.8{\sim}167.3m^3$, as compared to three disconnected bioretentions at their maximum amount of precipitation with non-effluent from the connecting three bioretentions. Hence, connecting LID-BMPs could improve the removal efficiencies of surface runoff volume and nonpoint source pollution.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.149-158
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• 2008

The parameters of each basin, required for the accurate analysis of flood runoff using Storage Function Model, are estimated. Prior to the estimation, sensitivity analysis and extraction of new regional topographic factors for Han River basin are conducted. Based on the result, the outflow constant of basin model is calculated through regression analysis in relation with pre-flood runoff depth. The storage constant of basin model is derived by the optimum storage constant equation, according to the flood event of each basin. The model using the mentioned parameters was compared with K-Water model of Korea Water Resources Corporation and the model of Han River Flood Control Office, and proved to correspond to the observed hydrograph more.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.303-308
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• 1998

A grid-based KInematic were STOrm Runoff Model (KIMSTORM) with predicts temporal and spatial distributions of saturalted orerland flow, subsurface flow and stream flow in a watershed was developed. The model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each grid element by using grid-based water balance of hydrologic components. The model which is programmed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS(Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture within the watershed.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.72-77
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• 2019

Soil type in LID infiltration practices plays a major role in runoff reduction efficacy. In this study, the effects of infiltration rate of foundation ground under bioretention on annual runoff reduction rate was evaluated using LIDMOD3 which is a simple excel based model for evaluating LID practices. A bioretention area of about 3.2 % was required to capture surface runoff from an impervious area for a 25.4 mm rainfall event. The relative error of runoff from bioretention using LIDMOD3 is 10 % less than that of SWMM5.1 for a total rainfall event of 257.1 mm during the period of Aug. 1 ~ 18, 2017, hence, the applicability of LIDMOD3 was confirmed. Annual runoff reduction rates for the period 2008 ~ 2017 were evaluated for various infiltration rates of foundation ground under the bioretention which ranged from 0.001 to 0.600 m/day and were converted to annual runoff reduction for hydrologic soil group. The runoff reduction rates within hydrologic soil group C and D were steeply increased through increased infiltration rate but not steep within hydrologic A and B with reduction rates ranging from 53 ~ 68 %. The estimated time required to completely empty a bioretention which has a storage depth of 0.632 m is 3.5 ~ 6.9 days and we could assume that the annual average of antecedent rainfall is longer than 3.5 ~ 6.9 days. Therefore, we recommended B type as the minimum hydrologic soil group installed LID infiltration practices for high runoff reduction rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6B
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• pp.697-707
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• 2008

The grid-based KIneMatic wave STOrm Runoff Model (KIMSTORM) by Kim (1998) predicts the temporal variation and spatial distribution of overland flow, subsurface flow and stream flow in a watershed. The model programmed with C++ language on Unix operating system adopts single flowpath algorithm for water balance simulation of flow at each grid element. In this study, we attempted to improve the model by converting the code into FORTRAN 90 on MS Windows operating system and named as ModKIMSTORM. The improved functions are the addition of GAML (Green-Ampt & Mein-Larson) infiltration model, control of paddy runoff rate by flow depth and Manning's roughness coefficient, addition of baseflow layer, treatment of both spatial and point rainfall data, development of the pre- and post-processor, and development of automatic model evaluation function using five evaluation criteria (Pearson's coefficient of determination, Nash and Sutcliffe model efficiency, the deviation of runoff volume, relative error of the peak runoff rate, and absolute error of the time to peak runoff). The modified model adopts Shell Sort algorithm to enhance the computational performance. Input data formats are accepted as raster and MS Excel, and model outputs viz. soil moisture, discharge, flow depth and velocity are generated as BSQ, ASCII grid, binary grid and raster formats.

• Journal of Korea Water Resources Association
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• v.33 no.S1
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• pp.20-27
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• 2000

The grid-based KIneMatic wave STOrm Runoff Model(Kim, 1998; Kim, et al., 1998) which predicts temporal variation and spatial distribution of saturated overland flow, subsurface flow and stream flow was evaluated at two watersheds. this model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each cell by using water balance of hydrologic components. the model programmed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS (Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture of the watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2000.05a
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• pp.20-27
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• 2000

The grid-based KlneMatic wave STOrm Runoff Modei (Kim, 1998; Kim, et al., 1998) which predicts temporal variation and spatial distribution of saturated overland flow, subsurface flow and stream flow was evaluated at two watersheds. This model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each cell by using water balance of hydrologic components. The model programed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS (Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture of the watershed.