• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.358-363
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• 2009

The HSPF (Hydrological Simulation Program-Fortran) model was applied to the Kyoungan stream watershed to analyze effects of watershed management plans on receiving water qualities. Utilizing BASINS 3.1 GIS program, the Kyoungan stream watershed was divided into 57 sub-basins and model input parameters were obtained, from DEM (Digital Elevation Model), land use type, stream map, and wastewater treatment facilities, etc.. The hydrologic module of the model was validated based on the measured meteorological data and stream flow data. Then the model was calibrated and verified against the field measurements of water qualities, including temperature, DO, BOD, $NO_3-N$, $NH_3-N$, Org-N, TN and TP. In most cases, there were reasonable agreements between measurements and predictions. The validated model was used to analyze the water quality improvements in the main stream of Kyoungan stream according to the watershed management plans in sub-basins, which are three different scenarios: water quality improvement in tributaries through watershed management activities, expansion and up-grade of wastewater treatment plants, and application of first and second scenarios together. It was concluded that expansion and upgrade of wastewater treatment plants would be more effective than watershed management activities. In order to improve water qualities to the satisfactory level, both watershed management and point source control must be required in the Kyoungan stream.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.97-107
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• 1989

An inverse self-iterative procedure is developed to estimate layer moduli of 3 layered flexible pavement structures from FWD deflection basins. The theoretical deflection basins of pavement structures obtained by full factorial design are used for the parametric study on the characteristics of deflection basins and the regression analysis. The factorial design is performed for asphalt pavement structures with stabilized base layer and granular base layer, respectively. The initially assumed layer moduli by regression equations and relations between the rate of change of moduli and deflections are used in the procedure to ensure efficiency and accuracy of self-iterative model. The SINELA computer program is used for inverse self-iterative applications to determine theoretical responses. The computer program of this procedure is coded for personal computers and is verified through numerical model tests.

• Journal of Korea Water Resources Association
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• v.49 no.3
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• pp.177-186
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• 2016

Drought is a water-related natural disaster which can be simply described as spatially and temporally sequential absence of water. However, its characteristics are very difficult to define. For this reason, the preparation and mitigation from drought events have not been successful. In the current study, we illustrated a design drought estimation approach of water resources infrastructures as well as the existing theoretical one to prepare and mitigate drought disasters. Theoretical and simulation methods were tested including three time series models such as autoregressive (AR), Gamma AR, Copula AR models. The results indicated that for South Korea region, the simulation-based method to estimate drought frequency presented better performance and all the three time series models show similar performance to each other. The current drought event occurring in South Korea was investigated with dividing South Korea into four basins as Han River, Nakdong River, Geum River, and Nakdong River basins. The results showed that two middle and north basins presented significant drought events with 3 year drought duration and around 40 year return period while the other two southern regions illustrated relatively weaker drought events.

• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.36-44
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• 2013

HSPF model based on BASINS was applied to analyze effects of watershed management measures for water quality conservation in the Hwaseong Reservoir watershed. The model was calibrated against the field measurements of meteorological data, streamflow and water qualities ($BOD_5$, T-N, T-P) at each observatory for 4 years (2007-2010). The water quality characteristics of inflow streams were evaluated. The 4 scenarios for the water quality improvement were applied to inflow streams and critical area from water pollution based on previous researches. The reduction efficiency of point and non-point sources in inflow streams was evaluated with each scenario. The results demonstrate that the expansion of advanced treatment system within wastewater treatment plants (WWTPs) and construction of pond-wetlands would be great effective management measures. In order to satisfactory the target water quality of reservoir, the measures which can control both point source and non-point source pollutants should be implemented in the watershed.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.201-213
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• 2007

In this study, the Batter Assessment Science Integrating point and Nonpoint Sources (BASINS 3.0)/window interface to Hydrological Simulation Program-FPRTRAN (WinHSPF) was applied for assessment of Soyang Dam watershed. WinHSPF calibration was performed using monitoring data from 2000 to 2004 to simulate stream flow. Water quality (water temperature, DO, BOD, nitrate, total organic nitrogen, total nitrogen, total organic phosphorus and total phosphorus) was calibrated. Calibration results for dry-days and wet-days simulation were reasonably matched with observed data in stream flow, temperature, DO, BOD and nutrient simulation. Some deviation in the model results were caused by the lack of measured watershed data, hydraulic structure data and meteorological data. It was found that most of pollutant loading was contributed by nonpoint source pollution showing about $98.6%{\sim}99.0%$. The WinHSPF BMPRAC was applied to evaluate the water quality improvement. These scenarios included constructed wetland for controlling nonpoint source poilution and wet detention pond. The results illustrated that reasonably reduced pollutant loadin. Overall, BASINS/WinHSPF was found to be applicable and can be a powerful tool in pollutant loading and BMP efficiency estimation from the watershed.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.200-211
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• 2009

A mathematical modeling program called Soil and Water Assessment Tool (SWAT) developed by USDA was applied to Kyongan stream watershed. It was run under BASINS (Better Assessment Science for Integrating point and Non-point Sources) program, and the model was calibrated and validated using KTMDL monitoring data of 2004${\sim}$2008. The model efficiency of flow ranged from very good to fair in comparison between simulated and observed data and it was good in the water quality parameters like flow range. The model reliability and performance were within the expectation considering complexity of the watershed and pollutant sources. The results of pollutant loads estimation as yearly (2004${\sim}$2008), pollutant loadings from 2006 were higher than rest of year caused by high precipitation and flow. Average non-point source (NPS) pollution rates were 30.4%, 45.3%, 28.1% for SS, TN and TP respectably. The NPS pollutant loading for SS, TN and TP during the monsoon rainy season (June to September) was about 61.8${\sim}$88.7% of total NPS pollutant loading, and flow volume was also in a similar range. SS concentration depended on precipitation and pollution loading patterns, but TN and TP concentration was not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. SWAT based on BASINS was applied to the Kyongan stream watershed successfully without difficulty, and it was found that the model could be used conveniently to assess watershed characteristics and to estimate pollutant loading including point and non-point sources in watershed scale.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.30-30
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• 2018

Research on mapping levees is an important task for assessing levee stability. The drone imagery acquired in river basins is useful for generating real-time levee maps. This research proposes a robust methodology for mapping levees in river basins using the drone imagery. In the first step, the multiple imagery taken in the test bed was acquired by the drone. Then, the orthorectified image and DEM (Digital Elevation Model) were generated by the photogrammetry and image processing process. Finally, the significant features on levee surfaces such as levee tops, levee lines, levee slopes, eroded areas were detected from the generated DEM and orthorectified image by manual labors and automatic methods. In future research, the automatic procedure for identifying the significant levee features from the drone imagery would be proposed.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.329-340
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• 2013

A geologic survey of the Bukpyeong and Pohang basins, as candidate basins for the geological storage of $CO_2$, was performed to evaluate storage capacity and security. To analyze the mechanical stability of the storage reservoir and cap rocks, we measured the porosity, seismic velocity, uniaxial strength, internal frictional angle, and Young's modulus of core samples recovered from the two basins. It is costly and sometimes impossible to conduct tests over the entire range of drill holes, and continuous logging data do not yield the mechanical parameters directly. In this study, to derive the mechanical properties of geologic formations from the geophysical logging data, we determined the empirical relations between the physical properties (seismic velocity, porosity, and dynamic modulus) and the mechanical properties (uniaxial strength, internal friction angle) of the core samples. From the comparison with our core test data, the best fits to the two basins were selected from the relations suggested in previous studies. The relations between uniaxial strength, Young's modulus, and porosity of samples from the Bukpyeong and Pohang basins are more consistent with certain rock types than with the locality of the basins. The relations between the physical and mechanical properties were used to estimate the mechanical rock properties of geologic formations from seismic logging data. We expect that the mechanical properties could also be used as input data for a modeling study to understand the mechanical instability of rock formations prior to $CO_2$ injection.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.281-288
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• 2004

The objective of this study is to propose a methodology of the flood runoff analysis in steep mountainous basins and the analysis basin is the Jasa valley basin in Chungju city Analyzing the spatial pattern of the rainfall in 1994. 6 30~7.1, the seasonal rainy front was tied up in the whole central district, and the rainfall center was moving from the northern Chungbuk province to the northern Kyongbuk province and caused heavy storm. Analyzing the temporal pattern with the Huff method, the 52.5% of the rainfall was concentrated on the 3rd quartile. Rainfall frequency analysis is accomplished by five distribution types; 2-parameter Lognomal, 3-parameter Lognomal, Pearson Type III, Log-Pearson Type III and Extremal Type I distribution Rainfall-runoff analysis in Jasa valley basin was made using HEC-HMS model. Jasa valley basin was divided into 3 sub-basins and the analysis point was 3 points{A, B and C point) With the rainfall data measured by the 10 minutes, the flood runoff also was calculated by as many minutes. SCS CN model, Clark UH model and Muskingum routing model in HEC-HMS model were used to simulate the runoff volume using selected rainfall event.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.69-78
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• 2009

In order to improve water quality of upper watershed of Paldang reservoir, it is necessary to evaluate non-point source pollution loads and identify critical watershed pollution sources. A GIS based Soil and Water Assessment Tool was applied to evaluate model application and reliability, estimate NPS pollution load, identify critical watershed by NPS pollution sources, and suggest various best management practices for Kyongan Stream watershed. Yearly NPS pollution loads were estimated 30.0% SS, 60.1% TN and 35.4% TP, respectably. The watershed pollution load is mainly decided by precipitation condition and SS and nutrients load have a significant regression relationship. Based on 10-year average yearly NPS pollution load, critical sub-watersheds were identified. The No. 5 and 17 which have lots of relatively intensive agricultural fields and scattered industrial area were vary critical sub-watersheds and under more intensive pollution load. In order to control critical watershed, watershed best management practices such as scientific fertilizer, contour farming and parallel terrace, transferring the sloppy farmland to grass or forest and constructing a buffer zone, and constructing wetlands and retention ponds will be applied. Overall the SWAT model can be efficiently used for identification of critical sub-watersheds in order to develop a priority watershed management plan to reduce water pollutions.