• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.699-704
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• 2005

합리식(rational formula)은 일정한 강우강도를 갖는 호우로 인한 소유역의 첨두홍수량을 결정할 때 대표적으로 사용되고 있다. 기존의 합리식 틀 안에서 유역의 기하학적인 형상이 타원의 형태와 비슷하다면 유역의 형상을 고려한 수정된 합리식으로 첨두홍수량을 결정할 수 있다. 수정된 합리식에서는 강우가 전체 지속시간 동안 유역에 균등하게 분포한다는 기존의 합리식의 가정과는 달리 강우가 유효우량주상도의 각 시간간격에 균등하게 분포한다고 가정한다. 이러한 가정은 강우 지속시간이 도달시간 보다 작은 경우에도 합리식을 적용할 수 있음을 나타낸다. 따라서 본 연구에서는 유역의 기하학적인 형상이 타원형에 가까운 예곡천 유역에 합리식과 수정합리식을 적용 한 후 그 결과를 비교 분석하였다. 그 결과 수정합리식에의한 첨두유량이 합리식보다 상당히 적게 산정되었다. 이는 합리식이 식생이 발달한 투수유역에서 첨두유량을 과다 산정한다는 기존 연구결과와 일치하는 것이다. 따라서 수정합리식은 합리식 가정의 한계를 보완하면서 비교적 단순한 프로세스를 유지하고 있어 조건이 부합되는 소유역에서 유용할 것으로 판단되었다.

• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.649-659
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• 1997

The influence of polluted water discharged from the Saemankeum Lake is predicted by using two-dimensional finite element model. The simulation results show that influence of the Polluted water to the northern part of the Kckunsan Islands is small during flood time. The reason is because lock gates are located in the south of the Kokunsan Islands so that tidal current directing north is blocked by these Islands. However, during the ebb time, the influence of the polluted water is extended to the whole southern part of the Kokunsan Islands. When the amount of ten percent of the total volume of polluted water is discharged from the Saemankeum Lake, equi-concentration contour line of one tenth of initial discharge concentration includes the inner area surrounded by Sinsi Island, Munyeo Island, Bian Island, and Daehang-Li. In general, peak concentration near the lock gates is found out to be higher during the spring tide than the neap tide.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.78-83
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• 2018

Recently, due to the rapid industrialization and urbanization, a great number of infrastructure and population were concentrated in urban areas. These changes have resulted in unprecedent runoff characteristics in urban basins, and the increase in impermeable areas leads to the growth of the runoff and the peak flow rate. Although many cities have made a lot of efforts to check and expand the stormwater network, the flash flood or the local torrential rain caused a growing number of casualty and property damage. This study analyzed the stormwater passage rate in a target area using SWMM. By incorporating the flow quantity surpassing the storm sewer capacity, a 2D inland flooding analysis model was applied to route the inundated area and velocity.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.5
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• pp.565-572
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• 2009

Hydraulic modeling is widely used to simulate wastewater flow. The simulated models are used to prevent flood and many other problems associated with wastewater flow in planning or rehabilitating sewer systems. In this study, MAKESW (An engineer, South Korea), MOUSE (DHI, Denmark), and SWMM (XPSoftware, USA) are used to for hydraulic modeling of wastewater in C-city, South Korea and E-city, Iraq. These modeling tools produced different results. SWMM comparably overpredicted runoff and peak flow. In using SWMM, use of accurate data with a high confidential level, detail examination over the target basin surface, and the careful selection of a runoff model, which describes Korea's unique hydraulic characteristics are recommended. Modification of existing models through the optimization of variables cannot be achieved at this moment. Setting up an integrated modeling environment is considered to be essential to utilize modeling and further apply the results for various projects. Standardization of GIS database, the criteria for and the scope of model application, and database management systems need to be prepared to expand modeling application.

• The Journal of Engineering Research
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• v.6 no.1
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• pp.75-81
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• 2004

To solve the urban flood problems, it must get the enough channel conveyances and pumping capacities. It needs set up the detention system to control the flow over the channel capacity. Inspite of this detention system, the peak flow may increased by rainfall distribution and the delay of flow. This shows a design model of detention system which can consider the time problems from mutual connections of the detention storages and pumping flow using IDP(Incremental Dynamic Programming) method.

• Advances in materials Research
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• v.6 no.2
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• pp.155-168
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• 2017

The terrorist attacks and dangers by bomb blast have turned into an emerging issue throughout the world and the protection of the people and structures against terrorist acts depends on the prediction of the response of structures under blast and shock load. In this paper, behavior of aluminum and unidirectionally reinforced E-Glass Epoxy composite plates with and without focal circular holes subjected to shock loading has been identified. For isotropic and orthotropic plates (with and without holes) the classical normal mode approach has been utilized as a part of the processing of theoretical results. To obtain the accurate results, convergence of the results was considered and a number of modes were selected for plate with and without hole individually. Using a shock tube as a loading device, tests have been conducted to composite plates to verify the theoretical results. Moreover, peak dynamic strains, investigated by experiments are also compared with the theoretical values and deviation of the results are discussed accordingly. The strain-time histories are likewise indicated for a specific gauge area for aluminum and composite plates. Comparison of dynamic-amplification factors between the isotropic and the orthotropic plates with and without hole has been discussed.

• Journal of Korean Society on Water Environment
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• v.23 no.1
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• pp.52-63
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• 2007

The objectives of this study were to setup a laterally-averaged two-dimensional eutrophication model in Daecheong Reservoir, and to validate the model under two different hydrological conditions; drought year (2001) and wet year (2004). The suggested modeling approach was found to be very effective to simulate the dynamic variations of water temperature, nutrients, dissolved oxygen, and algae in the reservoir. The model satisfactorily replicated the algal bloom that happened between Janggae (Sta.4) and Haenam (Sta.5) during summer of 2001, although the peak concentration was slightly underestimated due to the laterally averaged assumption. The allochthonous phosphorus and algae induced from upstream and So-oak stream during several rainfall events were found to be most significant sources of algal bloom in 2001. In contrast to draught year, the flood events happened during summer months of 2004 tended to remove the hypolimnetic anaerobic conditions and dilute the dissolved phosphorus in the upper reach of the reservoir, and in turn mitigated algal bloom. It implies that the impact of hydrological and hydrodynamic conditions on the reservoir water quality is highly significant, and a drought year may be more vulnerable to algal bloom in the reservoir.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.573-579
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• 2009

The performance of Rainfall-Runoff Forecasting System (RRFS), the watershed management model for the Geum river basin, is evaluated based on the agreement between the simulated and observed hydrographs and the behavioral characteristics of the flow-duration curves. As a result, the simulated hydrographs are well agreed with the observed ones except high flow discharges. It is inferred that most of the errors in the simulated hydrographs are due to the misestimation of agricultural water use in $2^{nd}$ quarter and the discrepancy of the peak discharges in $3^{rd}$ quarter. It is however judged that RRFS would give the reliable runoff hydrographs from the point of view of continuous model application. And simulated flow-duration curves and flow-duration coefficients are also similar to the observed ones except flood flow region. From the above result it is confirmed that the construction of Yongdam dam improves the state of flow-duration curve at the Gongjoo station.

• Water for future
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• v.21 no.1
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• pp.87-94
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• 1988

Tidal asymmetry in the Keum River Estuary has been investigated from the observed tides. Despite strong frictional attenuation within the estuary, the $M_4$ tides reach significant amplitude, resulting in strong tidal distortion. The observed asymmetry over the area shows that generally more intense flood flows transport more sediment that do less intense ebb flows of longer duration. This causes filling of the estaury as evidenced by sand flats spreaded over the inner area. The spatial distribution of peak bottom stress associated with the dominant $M_2$ and $M_4$ tides calculated via two-dimensional numerical tidal model suggest that present tidal sedimentation regimemay be altered, sepecially in the approach channel to outer Kunsan Port and downstream part of the dike, due to the construction of barrier.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.31-43
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• 1989

Tidal asymmetry and the associated sediment dynamics in the Keum River Estuary has been investigated from a numerical tidal model. Modeling efforts were focussed on the simulation of large drying sandflat exposed at the mouth of the Estuary and dynamic combination of two-dimensional estuary model and one-dimensional river model. Despite strong frictional attenuation within the estuary, the M4 tides reach significant amplitude, resulting in strong tidal distortion. Model results show that the asymmetry over the area exhibit more intense flood flows transport than do less intense ebb flows of longer duration. This causes filling of the estuary as evidenced by large sandflats spread over the inner area. The spatial distribution of peak bottom stress computed from the tidal model suggest that present tidal sedimentation regime may be altered significantly, especially in the approach channel to outer Kunsan port and downstream part of the dike, due to the construction of cross-channel barrier.