• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.192-192
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• 2016

Nowadays, stormwaters have been affected by urbanization and climate change. These transition can cause many problems for hydrologic cycle by increasing runoff volume like flood and low water quality. As with other metropolises and peninsulas, Busan has involved with these problems too. Therefore, it is really vital to do some arrangements to solve them by low impact development (LID) technology. In fact, LID has been introduced to reduce runoff by applying some techniques such as green infrastructure (GI). In order to deal with the aforementioned issues in Busan, this study attempts to design and construct a hybrid green roof-planter box system at Pusan National University GI/LID Facility based on local weather. For this purpose, we used experiment and modeling method on some planter boxes and optimized them by trial and error method.

• Journal of Korea Water Resources Association
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• v.52 no.12
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• pp.1011-1023
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• 2019

Rapid urbanization increases the risk of hydrologic disasters due to the increase of impervious areas in urban areas. Precipitation characteristics can be transformed due to the rise of global temperatures. Thus urban areas with the increased impervious areas are more exposed to hydrological disasters than ever before. Therefore, low impact development practices have been widely installed to rehabilitate the distorted hydrologic cycle in the urban area. This study used the Stormwater Management Model to analyze the water quantity and quality of the Mokgamcheon which had been severely urbanized, considering future climate scenarios presented by various general circulation models (GCMs). In addition the effectiveness of permeable pavement by 27 sub-watersheds was simulated in terms of water quantity and quality considering various GCMs and then the priorities of sub-watersheds were derived using an alternative valuation index which uses the pressure-state-response framework.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.3
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• pp.135-148
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• 2018

Reservoir sedimentation is a major environmental issue, and various sediment load controls and plans have been proposed to secure clean and safe water resources. The objectives of this study were to estimate soil loss in the upper basins and predict sediment deposition in Ipjang reservoir using hydrologic and hydraulic model. To do so, SWAT (Soil and Water Assessment Tool) and EFDC (Environmental Fluid Dynamics Code) was used to estimate soil loss in two upper basins and to predict spatial distribution and amount of sediment deposition in the Ipjang reservoir, respectively. The hydrologic modeling results showed that annual average soil loss from the upper basins was 500 ton. The hydraulic modeling results demonstrated that sediment particles transported to the reservoir were mostly trapped in the vicinity of the reservoir inlet and then moved toward the bank over time. If long-term water quality monitoring and sediment survey are performed, this study can be used as a tool for predicting the dredging amount, dredging location and proper dredging cycle in the reservoir. The study findings are expected to be used as a basis to establish management solutions for sediment reduction.

• Journal of Korea Water Resources Association
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• v.53 no.5
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• pp.357-367
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• 2020

It is usually not easy to simulate the hydrologic cycle or water quality for ungaged watersheds, especially for long-term simulation. In this paper we evaluated the applicability of GSSHA, a process-based distributed hydrologic model, for the long-term discharge and water quality simulation for the ungaged Peace dam watershed. From the comparative analysis of the simulated discharge and water quality series with measured ones, we concluded that with its overall fair performance on simulating hydrograph patterns of the peak discharges and base flows for major storms the GSSHA model showed some possibility to be used as a watershed model even with its overestimation of peak discharges for small storms and different trends of simulated water quality from measured ones for some periods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3B
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• pp.285-291
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• 2011

Accurate assessment of the water and energy cycles is essential to understand hydrologic, climatologic, and ecological processes. Common Land Model (CLM) is one of the well-developed Soil-Vegetation-Atmosphere Transfer (SVAT) models based on the water and energy balance equation for accurate prediction of hydro-environmental cycles. The CLM can estimate realistic and reliable results using relatively simple parameters. It has been widely used in the world, however in Korea practical applications of the CLM are rare due to lack of information and input data. In this study, the CLM with Korea Flux network (KoFlux) and Kore Land Data Assimilation System (KLDAS) data were individually validated for domestic applications. This study showed that all comparisons between observations and model results from KoFlux and KLDAS had reasonable correlation with determination coefficient of 0.73~1.00 via regression. The results confirmed the applicability of the CLM and the possibility of the KLDAS usage for the region where input data are not existed.

• Journal of the Korean GEO-environmental Society
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• v.20 no.3
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• pp.5-14
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• 2019

This study attempted to study the soil erosion dynamic in the Bagmati Basin of Nepal. In this study, an inclusive methodology that combines Revised Universal Soil Loss Equation (RUSLE) and GIS techniques was adopted to determine the distribution of soil loss in the study basin. As well, this study attempts to study the intensity of soil erosion in the seven different land use patterns in the Bagmati Basin. Soil loss is an associated phenomenon of hydrologic cycle and this dynamic phenomenon possesses threats to sustainability of basin hydrology, agriculture system, hydraulic structures in operation and overall ecosystem in a long run. Soil conservation works, and various planning and design of watersheds works demands quantification of soil loss. The results of the study in Bagmati Basin shows the total annual soil loss in the basin is 22.93 million tons with an average rate of 75.83T/ha/yr. The computed soil loss risk was divided into five classes from tolerable to severe and the spatial pattern was mapped for easy interpretation. Also, evaluation of soil loss in different land use categories shows barren area has highest rate of soil loss followed by agriculture area. This is a preliminary work and provides erosion risk scenario in the basin. The study can be further used for strategic planning of land use and hydrologic conservation works in a basin.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.2
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• pp.85-96
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• 2021

Irrigation return flow is defined as the excess of irrigation water that is not evapotranspirated by direct surface drainage, and which returns to an aquifer. It is important to quantitatively estimate the irrigation return flow of the water cycle in an agricultural watershed. However, the previous studies on irrigation return flow rates are limitations in quantifying the return flow rate by region. Therefore, simulating irrigation return flow by accounting for various water loss rates derived from agricultural practices is necessary while the hydrologic and hydraulic modeling of cultivated canal-irrigated watersheds. In this study, the irrigation return flow rate of agricultural water, especially for the entire agricultural watershed, was estimated using the SWMM (Storm Water Management Model) module from 2010 to 2019 for the Madun reservoir located in Anseong, Gyeonggi-do. The results of SWMM simulation and water balance analysis estimated irrigation return flow rate. The estimated average annual irrigation return flow ratio during the period from 2010 to 2019 was approximately 55.3% of the annual irrigation amounts of which 35.9% was rapid return flow and 19.4% was delayed return flow. Based on these results, the hydrologic and hydraulic modeling approach can provide a valuable approach for estimating the irrigation return flow under different hydrological and water management conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5330-5336
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• 2011

It becomes more and more important to develop various infiltration facilities for healthy water cycle and reduction of urban storm water runoff. In this study, a infiltration facility by utilizing tree box was developed. The developed facility is capable of reducing storm water road runoff, improving urban water cycle, and performing other sustainable and environmental functions. Because the facility can be manufactured to a smaller size than an existing runoff reduction facility, it can be installed at various road types of not only existing urban areas, but new developed areas. If the facility is applied to four-lane roadways, it is expected to reduce 65% of rainfall runoff discharge. Urban flood control improvement can be accomplished by a wide application of the developed technique.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.16-29
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• 2017

It is known that large-scale deforestation has occurred in North Korea due to economic failures since the 1990s, and this is expected to greatly change the characteristics of the hydrological cycle. In this study, hydrological cycle simulation was carried out for the period of about 30 years from 1981 to 2013 for the entire Korean peninsula using the VIC model, a land surface hydrology model. The simulation results are summarized as follow. First, the runoff ratio is 55%~70% in South Korea and 38~56% in North Korea. In particular, it is worth noting that despite the small runoff ratio, the variation is about 28% larger than the South Korea's 15%. The rate of evapotranspiration was larger than that of South Korea. That is, the rate of evapotranspiration in South Korea is 20~35% and in North Korea it is 25~46%. However, the rate of change was 21% in the case of North Korea and slightly larger than 15% in South Korea. Third, South Korea has an average of 34% in soil moisture and 27% in North Korea. However, unlike the simulated results of the runoff ratio and the evapotranspiration rate, the difference in the variation of soil moisture in South Korea and North Korea over the entire period was similar with 8%. As a result, we can confirm that the difference of hydrological cycle characteristics between South Korea and North Korea has been increased since the 1990s, when the forest destruction of North Korea became serious. In the case of South Korea, there is little difference in the hydrological cycle characteristics. In North Korea, however, there is a distinct difference, which is also a result reflecting the difference in the effects of forest destruction.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.121-121
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• 2011

도시유역 물순환 해석 모형(Catchment hydrologic cycle Analysis Tool, CAT)은 기존의 개념적 매개변수 기반의 집중형 수문모형과 물리적 매개변수 기반의 분포형 수문모형의 장점을 최대한 집약하여, 도시유역 개발 전/후의 장/단기적 물순환 변화특성을 정량적으로 평가하고 물순환 개선시설의 효과적인 설계를 지원하기 위한 물순환 해석 모형이다. 이 모형은 수문학적으로 균일하게 판단되는 범위를 소유역으로 분할하여 지형학적 요인에 의한 유출 특성을 객관적으로 반영할 수 있으며, 개발 공간 단위별로 침투, 증발, 지하수 흐름 등의 모의가 가능하도록 하는 링크-노드 방식으로 개발되었다. 모형의 UI(User Interface)는 사용자가 손쉽게 모형을 적용/관리하고, 여러 시나리오를 동시에 효과적으로 모의하여 분석할 수 있도록 설계되었다. 또한, 모든 입/출력 자료를 엑셀이나 텍스트 형식과 연동되도록 하여 프로젝트별 매개변수 관리가 용이하도록 개발하였다. 특히 본 모형에서는 사용자의 목적에 맞는 다양한 물순환 개선시설(침투시설, 저류지, 습지, 빗물저장시설, 리사이클 및 외부급수 등)의 구현 및 모의가 가능하도록 개발하였다. CAT은 수자원의지속적확보기술개발사업(2008 ~ 2011)의 연구 성과로서 한국건설기술연구원에서 개발하였다. 2008년 말에 모형의 기본구조가 개발되었고, 2009년에는 세부 알고리즘인 증발산, 침투, 유역 유출, 지하수 유거, 하도추적 등의 모듈과 사용자 편의시스템이 개발되었다. 2010년에는 우리나라 논의 특성을 반영한 논 유출 해석 모듈 및 저류지, 침투시설, 습지, 빗물이용시설 및 하천에서의 취수와 도수 등과 같은 물순환 개선시설을 평가할 수 있는 모듈을 추가하여 개발하였으며 2010년 3월에 도시유역 물순환 해석 모형 1.0 베타 버전을 출시하였다. 2010년 12월 에는 1.0 베타 버전에 침투해석모듈(Green&Ampt, Horton), 논에서의 개량물꼬 배수, 침투녹지(Bioretention) 및 차집관거 기능을 추가하였고, 기타 GUI의 업그레이드 및 추가를 통하여 1.5 베타 버전을 출시하였다. 현재까지 여러 자연유역과 신도시 개발지역에 대한 적용을 통하여 모형의 적용성을 평가하였다. 본 연구에서는 기존의 자연유역과 신도시 개발지역 외에 농업용 저수지와 논 관개지구가 위치한 유역을 대상으로 모형의 적용성을 평가하고자 하였다. 대상유역은 농업용수 지구이며 농업수리시설의 종류와 규모가 다양할 뿐만 아니라 농촌유역으로써의 대표성을 가지고 기존의 관측자료가 풍부한 점 등을 고려하여 경기도 평택의 이동유역을 선정하였다. 이동유역은 행정구역으로는 경기도 용인시 이동면, 남사면 일원이며 서쪽은 경기도 오산시, 남쪽은 평택시, 안성시 그리고, 북쪽은 용인시와 인접하고 있다. 이동유역 내 주요시설로서 유역면적 $94.4km^2$의 이동저수지와 상류에 용덕저수지($12.41km^2$)와 미산저수지($4.39km^2$), 노곡저수지($2.00km^2$)의 3개 저수지가 위치하며 2개의 유입하천(진위천, 송전천)에 의해 이동저수지로 유입된다.