• Journal of Environmental Science International
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• v.24 no.8
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• pp.1065-1073
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• 2015

Urbanization can be significantly affected the hydrologic cycle by increasing flood discharge and heat flux. In order to mitigate these modifications in urban areas, Low Impact Development (LID) technique has been designed and applied in Korea. In order to estimate runoff reduction rate using SWMM LID model, the characteristics of five LID techniques was firstly analyzed for water balance. Vegetated swale and green roof were not reduce flood discharge nor infiltration amount. On the other hand, porous pavement and infiltration trench were captured by infiltration function. The flood reduction rate with LID is substantially affected by their structures and properties, e.g., the percentage of the area installed with LID components and the percentage of the drainage area of the LID components.

• Magazine of the Korean Society of Agricultural Engineers
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• v.8 no.1
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• pp.1071-1076
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• 1966

In this country grassed waterway practice has long been employed for the protection of drainage or diversion ditches in treating the sloped forest lands. However, the hydraulic characteristics of flow in the ditches have been entirely away from consideration in determining the dimensions of the ditches. This paper is intended first to bring forth some problems which should be brought ioto Consideration in designing grassed waterway including hydrologic aspect for determining the drainage requirement, erosion resistance of various grasses and other factors related to the hydraulics of ditch and second to introduce to readers a method of grassed waterway design, though modified, proposed for U. S. Soil Conservation Service practice. The method presented in the paper was primarily based upon the data originated from the experiments of U. S. Soil Conservation Service laboratories and further investigations on the factors involved are hoped to be conducted for applying the design criteria in this country. It is recommended to use the method of grassed waterway design ,presented in this paper from the view point of wide employment of grass lining on ditches which is obtainable at the lower cost and in abundance every where in this country.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.949-949
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• 2012

유출수문곡선은 강우량, 강우강도, 강우지속시간, 강우이동방향 및 이동속도와 같은 강우발생특성과 강수대의 공간적 이류방향과 유역형상과의 상호작용에 의하여 영향을 받으며, 특히 강우의 이류과정에서 나타나는 시간적, 공간적인 분포는 유출에 영향을 미치는 중요한 인자이다. 일반적으로 유출해석 기본이론은 연속방정식과 운동방정식으로서 운동파가정(kinematic wave analogy)을 기반으로 한 집중수문모형(lumped hydrologic model)에 의하여 수행되고 있지만 집중형 모형은 한 매개변수에 여러 가지의 물리적 과정을 개념화하여 담고 있기 때문에 유출과정에 대한 섬세한 모형화의 제약으로 인하여 강우의 이류과정에 따른 유출변화특성을 모의하기가 어렵다. 본 연구에서는 완전 분포형 수문동력학적 강우-유출 모형을 사용하여 강우의 이류특성을 반영할 수 있는 유출 모델을 구성하고, 강우의 이류특성에 따른 유역 출구에서의 유출수문곡선의 변화과정을 살펴보고 상관관계를 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.150-150
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• 2021

Soil erosion due to climate change is one of the global environmental issues. Especially, Korea is vulnerable to soil erosion as the frequency of extreme rainfall events and rainfall intensity are increasing. Soil erosion causes various problems such as reduced farmlands, deterioration of water quality in rivers, etc. To these severe problems, understanding the process of soil erosion is the first process. Then, it is necessary to quantify and analyze soil ersoion using an erosion model. Soil erosion models are divided into empirical, conceptual, and physics-based models according to the structures and characteristics of models. This study used GSSHA (Gridded Surface Subsurface Hydrologic Analysis), the physics-based erosion model, running on WMS (Watershed Modeling System) to analyze soil erosion vulnerability of the CheonCheon watershed. In addition, we compared the six sediment transport capacity formulas provided in the model and evaluated the equations fir on this study site. Therefore, this result can be as a primary tool for soil conservation management.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.2_2
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• pp.173-180
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• 2020

In Korea, due to the rapid increase in population due to industrialization, rivers were developed and managed with a focus on the completion and dimension of rivers. Due to the rapid increase in river use, there are so many river facilities indiscriminately that the administrative and management tasks are complicated and diversified in computerizing facilities and hydrologic data. Many methods have been proposed to solve this problem, but many problems exist. Among them, water has the same spectral characteristics, so it is difficult to subdivide into rivers, reservoirs, and dams. Therefore, this study subdivided the water system using supervised classification and GIS in order to efficiently manage the water resources by classifying the water system with the same spectral characteristics. In order to analyze the accuracy of the results, the accuracy of the objects classified using land cover map provided by environmental spatial information service was evaluated, and the result was an average of 91.75%, with 97.50% of rivers, 87.76% of reservoirs, and 90.00% of others.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.532-539
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• 2010

The synthetic unit hydrograph is developed and verified using Nash model and characteristic velocities considering geomorphological dispersion in this present study. Application watersheds are selected 5 subwatersheds of Bocheong basin. The mean and variance of hillslope and stream path length are estimated in each watershed with GIS. Characteristic velocities are calculated using estimated path lengths and moment characteristics of rainfall-runoff data. Characteristic velocities of random devised 7 ungauged watersheds are estimated through regional analysis of chracteristic velocities in guaged watershed. And Nash model parameters and IUH are derived using characteristic velocities and path length in the gauged and ungauged watershed. The result to compare of IUH about gauged watershed and random devised ungauged watershed in application watershed presents coherently hydrologic response characteristics that peak discharge is reduced and peak time is extended. In conclusion, Developed synthetic unit hydrograph in this study expects that it is useful method to estimate runoff discharge for managing of water pollution in ungauged watershed.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.725-740
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• 2003

Urbanization concerned with concentration of population, activity and expanding the urban changes a natural environmental, and human activity in urban area causes the appearance of a new hydrologic cycle system. This study is carried out the analysis for the characteristics of runoff variation in urban areas with progress of urbanization. To simulate the mechanics of runoffs on small urban watershed, the ILLUDAS model is used in this study. From the analysis of the urban-runoff processes in small urban area with the progress of urbanization, the following conclusions is obtained. It is found in the results of calculated geographical parameter that peak time is quickened by 15∼35 minutes rather than the urbanization before. Also, in the analysis of the peak rate of runoff, the peak flow rise by 60 % than the urbanization before.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.910-915
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• 2009

The ecohydrologic characteristics according to planting in riparian zone for the riparian restoration are analyzed in this research. The ecohydrologic components due to land use change in riparian zone from existing land cover to planted area such as pasture and wildrye are simulated in the test basin with the integrated SWAT-MODFLOW model. After analysis of change of the hydrologic properties such as surface flow, lateral flow, transpiration and soil water in riparian zone, it is revealed that soil water is one of the key factors and planting of wildrye can increase soil water in riparian zone. The simulation performance of the SWAT-MODFLOW model is validated in this study and it is expected that this model can be used to evaluate various riparian restoration scenarios.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.11a
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• pp.389-392
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• 2004

A recent unusual change in the weather is formed as a localized heavy rain in a short time. This phenomenon has caused a flash flood, and flash floods extensively have damaged human lives many times. In large river's case, the extent of loss of lives and properties has been decreased through the flood warning system by flood control stations of each stream. However, the extent of damage in other small rivers has increased reversely. Therefore, it is necessary to establish a new flood warning system against flash floods instead of the existing flood warning system. It is a specific character that the damage from flash floods in mountain streams brings much more loss of lives than large river's flood. The purpose of this study is calculating the characteristic of flash floods in streams, analyzing topographical characteristics of water basin through applying GIS techniques with the calculation as mentioned above and researching what topographical conditions have influence on hydrological flash floods in water basin. The flash flood prediction model we used is made by GIUH (geomorphoclimatic instantaneous unit hydrograph) with hydrologic-topographical technology. As applying the flash flood prediction model, this is a procedure for calculating topographical information in basin: we made a topological data up out of database with utilizing GIS, and we also produced a DEM (digital elevation model) and used it as a topographical data for determining amount of flash floods.

• Spatial Information Research
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• v.14 no.1 s.36
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• pp.15-27
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• 2006

This paper is about the threshold discharge computation using GIUH(Geomorphoclimatic Instantaneous Unit Hydrograph) on ungauged small basin. GIUH is one of the possible approaches to predicting the hydrograph characteristics. This study is calculated the various ways which are hydrologic characteristics, bankfull flows, unit peak flows(the Clark, the Nakayasu and the S.C.S) as well as threshold runoffs on about $5km^2$ scale at Kyungbuk gampo in subbasin. We are estimated propriety that peak discharge calculated the GIUH from acquiring data by GIS(Geographic Information System) compared to observed peak discharge. And, the threshold discharge was calculated by NRCS(Natural Resources Conservation Service) for a flash flood standard rainfall.