• 대한토목학회논문집
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• 제34권3호
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• pp.785-794
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• 2014

유역에서의 수문반응은 기후요소뿐만 아니라 토지이용, 토양, 식생 등의 여러 가지 요소에 의한 복합적 상호작용에 의해 결정된다. 따라서 유역의 수문반응을 효과적으로 파악하기 위해서는 기후요소와 다른 외부요소에 대한 특성이해가 필요하다. 본 연구에서는 수문지수(건조지수, Horton 지수)를 적용하여 유역 수문반응에 영향을 미치는 기후 및 유역 특성의 상대적 영향력을 확인하고자 하였다. 우리나라 자연 유역에서는 건조지수보다는 Horton 지수를 이용하여 유역의 수문반응을 평가하는 것이 효과적이었다. 또한 기후상태에 따라 기후요소와 유역특성이 미치는 상대적인 영향력이 달라지는데, 건조한 기후상태에서는 기후요소가 지배적으로 수문반응에 영향을 미쳤으나 기후가 습윤한 상태로 갈수록 유역특성의 역할이 상대적으로 증가하고 있음을 확인하였다.

• 한국물환경학회지
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• 제36권6호
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• pp.568-580
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• 2020

Calibrating a conceptual hydrologic model necessitates selection of a calibration period that produces the most reliable prediction. This often must be chosen randomly, however, since there is no objective guidance. Observation plays the most important role in the calibration or uncertainty evaluation of hydrologic models, in which the key factors are the length of the data and the hydro-climate conditions in which they were collected. In this study, we investigated the effect of the calibration period selected on the predictive performance and uncertainty of a model. After classifying the inflows of the Hapcheon Dam from 1991 to 2019 into four hydro-climate conditions (dry, wet, normal, and mixed), a conceptual hydrologic partitioning model was calibrated using data from the same hydro-climate condition. Then, predictive performance and post-parameter statistics were analyzed during the verification period under various hydro-climate conditions. The results of the study were as follows: 1) Hydro-climate conditions during the calibration period have a significant effect on model performance and uncertainty, 2) calibration of a hydrologic model using data in dry hydro-climate conditions is most advantageous in securing model performance for arbitrary hydro-climate conditions, and 3) the dry calibration can lead to more reliable model results.

• 한국환경복원기술학회지
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• 제2권1호
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• pp.66-71
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• 1999

Main concern is to figure out the growth response of Pinus densiflora to hydrologic conditions in the central Korea. Continuous measurements were carried out with six trees with dendrometers in the Chungbuk National University experimental forest (Wolak-san) during 1995~1996. Surrounding hydrological conditions reflected by the solar radiation, air temperature, precipitation, soil water were included in measurements. Their effects on the biological response of trees was investigated and expressed as response functions. With these response functions, tree growth model was developed. Soil water availability was more related to the tree growth than air temperature. Limited number of biological measurements with dendrometer could permit determination of dynamics of radial tree growth to the hydrological conditions. Tree growth model could be used to check and revise the statistical transfer function of dendrohydrology.

• 한국물환경학회지
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• 제28권4호
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• pp.574-581
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• 2012

It is important to analyze the status of water quality with relation to the stream flow to attain water quality goal more effectively in the unit watersheds for the management of Total Maximum Daily Loads (TMDLs). This study developed a flow duration-water quality distribution graph to figure out water quality appearances on the flow variation and analyzed contributions of water quality observations to the impaired water bodies quantitatively by hydrologic conditions. Factors relating to water quality variation can be analyzed more precisely and assessed on the base of quantified contributions. It is considered that this approach could be utilized to establish a more effective plan for the water quality improvement including the prioritization of pollution reduction options.

• 한국농공학회지
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• 제30권1호
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• pp.50-62
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• 1988

This study refers to the development of a hydrologic model simulating daily inflow and release rates for irrigation reservoirs. A daily - based model is needed for adequate operation of an irrigation reservoir sufficing the water demand for paddy fields which is closely related to meteorological conditions. Inflow rates to a reservoir need to be accurately described, which may be simulated using a hydrologic model from daily rainfall data. And the objective of this paper is to develop, test, and apply a hydrologic model for daily runoff simmulation. A well - known tank model was selected and modified to simulate daily inflow rates. The model parameters were calibrated using observed runoff data from twelve watersheds, Relationships between the parameters and the watershed characteristics were derived by a multiple regression analysis. The simulation results were in agreement with the data. The inflow model was found to simulate low flow conditions more accurately than high flow conditions, which may be adequate for water resources utilization.

• 한국수자원학회논문집
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• 제45권6호
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• pp.597-606
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• 2012

DEM(Digital Elevation Model) 크기의 변화에 따라 특정 지역에 많은 규격의 수문 데이터가 존재할 수 있기 때문에, 어느 지역, 어느 기상 데이터에도 작동할 수 있는 수문 모형의 개발이 절실히 필요하게 되었다. 이와 같은 필요성을 설명하기 위해서 객체지향(object-oriented)적인 프로그래밍 기술을 적용한 GHISMO(Geographic and Hydrologic Information System Modeling Objects)라는 수문모형(hydrologic model)을 개발하였다. GHISMO의 가장 핵심적인 수문학적 접근방법은 저류-배출(storage-release)과 지표면 유효 강수량을 구하기 위하여 SCS curve number 방법을 사용한 것이다. 이 연구에서 수문모형의 모의실험 결과를 제공할 것이다.

• 한국환경과학회지
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• 제16권8호
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• pp.973-983
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• 2007

The eco-hydrologic effects of maintenance water supply on Oncheon stream are studied using hydrologic, hydraulic and ecologic models. SWMM (Storm Water Management Model) is used for long-term simulation of runoff quantity and water quality from Oncheon stream watershed. Using the output hydrologic variables from SWMM, HEC-RAS (River Analysis System) is then used to simulate the hydraulics of water flow through Oncheon stream channels. Such hydrologic, hydraulic and water quality output variables from SWMM and HEC-RAS are served as input data to execute PHABSIM (Physical Habitat Simulation) for the purpose of predicting the micro-habitat conditions in rivers as a function of stream flow and the relative suitability of those conditions to aquatic life. It is observed from the PHABSIM results that the weighted usable area for target fishes has the maximum value at $2m^3/s$ of instream flow. However, mid and down stream areas that have concrete river bed and covered region are unsuitable for fish habitat regardless of instream flow increment. The simulation results indicate that the simple maintenance water supply is limited in its effect to improve the ecological environment in Oncheon stream. Therefore, it is imperative to improve water quality and to recover habitat conditions simultaneously.

• 한국물환경학회지
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• 제36권3호
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• pp.229-244
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• 2020

Hydrologic models, as a useful tool for understanding the hydrologic phenomena in the watershed, have become more complex with the increase of computer performance. The hydrologic model, with complex configurations and powerful performance, facilitates a broader understanding of the effects of climate and soil in hydrologic partitioning. However, the more complex the model is, the more effort and time is required to drive the model, and the more parameters it uses, the less accessible to the user and less applicable to the ungauged watershed. Rather, a parsimonious hydrologic model may be effective in hydrologic modeling of the ungauged watershed. Thus, a semi-distributed hydrologic partitioning model was developed with minimal composition and number of parameters to improve applicability. In this study, the validity and performance of the proposed model were confirmed by applying it to the Namgang Dam, Andong Dam, Hapcheon Dam, and Milyang Dam watersheds among the Nakdong River watersheds. From the results of the application, it was confirmed that despite the simple model structure, the hydrologic partitioning process of the watershed can be modeled relatively well through three vertical layers comprising the surface layer, the soil layer, and the aquifer. Additionally, discussions were conducted on antecedent soil moisture conditions widely applied to stormwater estimation using the soil moisture data simulated by the proposed model.

• 한국환경과학회지
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• 제30권8호
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• pp.613-619
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• 2021

Soil water enters the atmosphere via evapotranspiration, where it transforms into atmospheric water vapor and plays important role in the surface-atmosphere energy exchange. Soil conditions have a direct influence on the effective rainfall, and initial soil moisture conditions are important for quantitatively evaluating the effective rainfall in a watershed. To examine the sensitivity of the initial saturation to hydrologic outflow, a two-dimensional distributed FLO-2D hydrologic model was applied to a small watershed. The initial saturation was set to 0.3, 0.5, and 0.7 and the obtained results were compared. The Green-ampt model was chosen to calculate the penetration loss. Depending on the initial soil moisture, the peak flow rate varied by up to 60%, and the total water volume in the watershed by approximately 40%.

• 한국농공학회논문집
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• 제49권5호
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• pp.81-90
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• 2007

Watershed topographical information is required in hydrologic analysis, supporting efficient hydrologic model operation and managing water resources. Watershed topographical data extraction systems based on desktop GIS are abundant these days placing burdens for spatial data processing on users. This paper describes development of a Web-based Geographic Information Systems that can delineate the Geum River sub-basins and extract watershed topographical data in real time. Through this system, users can obtain a watershed boundary by selecting outlet location and then extracting topographical data including watershed area, boundary length, average altitude, slope distribution about the elevation range with Web browsers. Moreover, the system provides watershed hydrological data including land use, soil types, soil drainage conditions, and NRCS(Natural Resources Conservation Service) curve number for hydrologic model operation through grid overlay technique. The system operability was evaluated with the hydrological data of WAMIS(Water Management Information System) with the government operation Web site as reference data.