• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.403-411
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• 2001

This paper investigates the applicability of a modified version of TOPMODEL considering shallow subsurface storm flow in a forested mountaneous catchment. The macroporous soil structure provides a hydrological pathway for rapid runoff generation. A modified version of TOPMODEL introduces the two-storage system to analyze the hydrograph recession including rapid subsurface storm flow component. The two-month continuous hydrologic simulations of sulmachun watershed suggest that a modified version of TOPMODEL represents comprehensive and realistic flow generation mechanism comparing to those of an original version of TOPMODEL. The results of parameter calibration with Monte-Carlo method indicate a modified version of TOPMODEL produces a set of physically meaningful parameters.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.515-524
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• 1999

A methodology to resolve a TOPMODEL problem has been suggested, which is associated with the spatial distribution of soil moisture behaviour in a runoff mechanism. A procedure to integrate the spatial information of saturation deficit in the TOPMODEL reflects the connectivity of saturated area in a watershed. The developed algorithm includes an improved basis in tracing the runoff path without increasing the number of parameters. The performance of the developed algorithm has been tested to an upland subwatershed, namely Dongok, which is the IHP watershed located at Wichon, Korea. Comparing with the original statistical version of the TOPMODEL, it has been found that the suggested algorithm can relax an overestimation of peak rate in the runoff simulation.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.826-829
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• 2005

유역의 수자원 분석을 위해서는 선정된 모형의 입력자료와 이를 바탕으로 추정된 매개변수의 결정이 매우 중요하다고 할 수 있다. 본 연구에서는 수문모형의 입력자료인 유역의 시간자료와 공간자료를 구축하고 이를 대상유역의 기준자료로 선정하여 HyGIS(Hydrological Geographic Information System)의 시$\cdot$공간DB에 저장하였다. 또한 TOPMODEL을 HyGIS와 연계시킴으로서 저장된 DB로부터 모형 구동에 필요한 시$\cdot$공간자료를 손쉽게 사용할 수 있는 시스템을 개발하였으며 이를 HyGIS-TOPMODEL이라고 한다. 연구결과 HyGIS-TOPMODEL은 HyGIS의 시$\cdot$공간DB를 이용하여 효과적으로 입력자료를 구성할 수 있었다. 또한 개발된 HyGIS-TOPMODEL을 시험유역에 적용한 결과 실측유량을 적절히 모의하는 것으로 나타났으며, 이에 따라 유전자 알고리즘을 이용한 매개변수의 추정 및 이의 적용 또한 타당한 것으로 나타났다.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.1035-1046
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• 2003

In order to evaluate the TOPMODEL's prediction ability for spatial distribution of water table depths, two major assumptions and governing equation of water table depth are tested. For the test, data of hydrological observations are used and a soil survey is made in the steep hillslope with thin soils. Responses of water table and hydraulic properties of soil are coincident with two major assumptions of the TOPMODEL's such as water table gradient parallel to the local topographical slope and exponential decline in transmissivity with depths. Soil texture and the decline rate of transmissivity(f) we homogeneous in space at the 0∼0.3m depths of the soil of the hillslope, but they are heterogeneous in space below its 0.3m depths due to the vertical change of soil texture and the ‘f’. It is shown that the TOPMODEL's equation can be used for simulating distribution of water table depth at the depths with uniform values of the 'f'.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.393-405
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• 2000

Monthly runoff was estimated using TOPMODEL which simulates ground water movement as well as surface runoff in the area of catchment. SAYUN dam which is being operated by Korea Water Resources Corporation was selected for the study, and the topographic factors of the watershed were analyzed using 1/5,000 digital map and GIS software(Arc/Info). The comparison shows good agreement between observed monthly runoff and the computation results simulated by using TOPMODEL. The catchment area of SAYUN dam was modeled by using various grid sizes in order to check the sensitivity of grid size, and the grid size of 180m was found most proper among 6 different sizes. TOPMODEL was also found superior to the existing monthly runoff models such as Kajiyama, KRIHS and Tank. Because the model requires limited number of parameters and considers topographic aspects, it is reckoned to be very useful for practical use.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.1-11
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• 2003

In this study, TOPMODEL(TOPography based hydrologic MODEL) was tested linked with Muskingum river routing technique for $581.7km^2$ Anseong-cheon watershed. Linear trend surface interpolation was used to give flow direction for flat areas located in downstream watershed. MDF (multiple flow direction) algorithm was adopted to derive the distribution of ln(a/$tan{\beta}$) values of the model. Because the coarser DEM resolution, the greater information loss, the watershed was divided into subwaterhseds to keep DEM resolution, and the simulation result of the upstream watershed was transferred to downstream watershed by Muskingum techniques. Relative error of the simulated result by 500 m DEM resolution showed 27.2 %. On the other hand, the relative error of the simulated result of 300 m DEM resolution by linked 2 subwatersheds with Muskingum method showed 15.8 %.

• Journal of Korea Water Resources Association
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• v.35 no.2
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• pp.125-136
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• 2002

The effects of the temporal scale of input hydrological data on runoff simulation have been studied using hydrological data with various time scales. TOPMODEL has been employed to explores these effects. The Genetic a1gorithm was used to calibrate model Parameters. The results of sensitivity analysis in various time scales provide the insight of parameter space for TOPMODEL operation of different time scale. The variation of temporal scale of input hydrological data appeared to have significant impacts on the model efficiency, average water table depth, the ratio of the surface runoff to the total runoff and the calibrated parameters. Generally, the longer the time scale, the more surface runoff and the less average water table death were calculated. It is found that the impact of lime scale to runoff simulation results from the structure of TOPMODEL and the hydrographic morphology.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.65-75
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• 2002

The objectives of this study are to analyse model-based soil moisture variations depending on model parameters m and $T_0$ and to evaluate the model performance for the simulation of soil moisture variations by the comparison of observed groundwater levels and model-driven soil moisture amounts and observed and simulated river discharges at the basin outlet. The selected study area is the Pyungchang IHP river basin with outlet at Sanganmi station and the summer flooding events during '94-'98 are used for the analysis. As a result, soil moisture holding capacity is increased according to increase the parameter m that represents effective groundwater depth. This phenomenon is especially dominant when higher m and $T_0$ values are used. The qualitative comparison of computed base flow and observed groundwater level shows that the base flow peaks are reasonably simulated and the decreasing limbs of hydrograph are mainly caused by base flows. It is concluded that TOPMODEL can be used effectively for simulating basin-averaged soil moisture variations in addition to river flow generations.

• Proceedings of the KGS Conference
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• 2002.11a
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• pp.45-48
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• 2002

TOPMODEL은 지표유출과 중간류유출을 비교적 적은 수의 매개변수와 물리적 근거를 기반으로 모의하는 수문모형이다. 현재까지 TOPMODEL은 온대습윤지역의 소유역 유출모의에 적용성이 우수하다는 연구결과가 많이 발표되었으며, 우리나라에서도 이 모델을 이용한 유역유출 모의에 탁월하다는 연구 결과들이 나오고 있다. 이런 연구들은 대부분 모델의 중요 매개변수를 유역유출 관측자료로부터 유도하고, 이 매개변수를 이용하여 유역유출을 모의한 연구들로 TOPMODEL에서 제시한 것 같은 유역내의 지하수위변화, 지표유출, 중간류유출 등의 수문학적 반응 발생여부를 조사하지 못하였다.(중략)

• Journal of Korea Water Resources Association
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• v.33 no.1
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• pp.87-98
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• 2000

The objective of this study is to test the flood forecasting capability of TOPMODEL on a single watershed in Korea. The selected study area is the Soyang River basin with outlet at Soyang Dam site. The three daily hydrographs and the three hourly flood events during 1990~1996 are selected for model calibrations and performance tests. The model parameters are estimated on 1990 daily event by manual fitting technique and the effects of topographic index distribution to river flow simulations are investigated on the study area. The model performance on correlation coefficient between the observed and the simulated flows for the verification periods are above 0.77 on the 95-, 96-daily events, while above 0.87 for 90-, 95-, 96-hourly events. By the consideration of flood flow characteristics in Korea, the physical interpretation of the model concept, and the model performance, it can be concluded that the TOPMODEL is feasible as a flood forecasting model in Korea. Korea.