• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.71-71
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• 2011

지난 세기동안 지구 평균 기온이 상승함에 따라 대기 중에 차지하는 수증기 함유량 또한 증가 추이를(7%/$^{\circ}C$) 보이고 있으며, 이는 전 세계적으로 수문 순환 패턴의 변화를 초래한다(IPCC, 2007). 그 중에서도 강수 특성의 변화는 궁극적으로 유출량의 변화를 초래하며, 이는 수자원 총량의 변화로 이어지게 된다. 특히, 여름철에 대부분의 강수 현상이 집중되는 우리나라의 경우 육지의 70% 정도가 산악 지형으로 이루어진 복잡한 지리적 영향으로 집중호우 시 홍수가 일시에 유출되어 이에 따른 인적 물적 피해가 해마다 되풀이 되고 있다. 수자원은 인간 생활과 밀접한 관계에 있기 때문에 이러한 극심한 기후변화에 의한 피해를 최소화하기 위해 수계단위의 효율적인 물관리가 필수적이다. 따라서 한반도 내 주요 강(한강, 금강, 영산강, 섬진강, 낙동강)을 중심으로 수계별 강수량 및 유출량의 장기 특성 변화를 살펴보고자 한다. 장기간의 자료를 보유하고 있는 기상청 산하 27개 지점의 시간 강수량 자료 및 국가 수자원관리 종합정보시스템에서 제공하는 장기유출 자료를 수집하여 수계 평균값을 산정하고, 각 수계별 강수량 및 유출량의 장기 추이 및 변동성, 상관도를 알아보고자 하였다. 최근 36년 동안(1973~2008년) 모든 수계에서 연총강수량이 증가하는 추이를 보였으며, 한강 수계에서 유의수준 5% 내에서 가장 높은 증가율(약 10 mm/yr)을, 섬진강 수계에서 가장 낮은 증가율(약 4 mm/yr)을 나타냈다. 여름철 집중호우(20 mm/hr 이상) 빈도 분석 결과, 모든 수계에서 호우 빈도의 증가 경향이 뚜렷함을 볼 수 있다. 특히, 최근 10년간(1999~2008) 호우빈도의 변화를 살펴보면 섬진강 수계의 경우 총 60번으로 가장 많았고 상대적으로 낙동강 수계에서 35번으로 가장 적었다. 여름철 무강수일수(강수량이 0.1 mm 미만인 일수)의 경우 모든 수계에서 거의 완만한 감소추세를 보임을 확인할 수 있었다. 1970~2001년간 연총유출량의 경우 한강 및 금강 수계의 경우 증가하는 경향을 나타내는 반면 섬진강 수계의 경우 오히려 감소하며, 영산강 및 낙동강 수계에서는 뚜렷한 변화를 볼 수 없었다. 월별 유출량의 경우 모든 수계에서 7월, 8월, 9월에 집중되며, 한강 수계에서 8월, 그 외 수계에서는 7월에 가장 높은 값을 보였다. 향후 장기적인 관점에서 바라 본 강수량과 유출량의 관계에 관한 추가적인 연구를 통하여 신뢰성 있는 기후변화에 따른 수자원 영향 평가에 기여할 수 있을 것으로 사료된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4B
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• pp.347-359
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• 2010

A simple web-based flood forecasting system using data from stage and rainfall monitoring stations was developed to solve the difficulty that real-time forecasting model could not get the reliabilities because of assumption of future rainfall duration and intensity. The regression model in this research could forecast future water level of maximum 2 hours after using data from stage and rainfall monitoring stations in Daejeon area. Real time stage and rainfall data were transformed from web-sites of Geum River Flood Control Office & Han River Flood Control Office based MS-Excel 2007. It showed stable forecasts by its maximum standard deviation of 5 cm, means of 1~4 cm and most of improved coefficient of determinations were over 0.95. It showed also more researches about the stationarity of watershed and time-series approach are necessary.

• Journal of Korean Society of Disaster and Security
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• v.14 no.2
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• pp.13-23
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• 2021

This study intended to assess the reliability of topographic data using satellite imaging data. The topographical data using actual instrumentation data and satellite image data were established and applied to the rainfall-leak model, S-RAT, and the topographical data and outflow data were compared and analyzed. The actual measurement data were collected from the Water Resources Management Information System (WAMIS), and satellite image data were collected from MODIS observation sensors mounted on Terra satellites. The areas subject to analysis were selected for two rivers with more than 80% mountainous areas in the Han River basin and one river basin with more than 7% urban areas. According to the analysis, the difference between instrumentation data and satellite image data was up to 50% for peak floods and up to 17% for flood totals in rivers with high mountains, but up to 13% for peak floods and up to 4% for flood totals. The biggest difference in the video data is Landuse, which shows that MODIS satellite images tend to be recognized as cities up to 60% or more in urban streams compared to WAMIS instrumentation data, but MODIS satellite images are found to be less than 5% error in forest areas.

• Journal of the Korean GEO-environmental Society
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• v.24 no.12
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• pp.31-38
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• 2023

In this study, runoff characteristics analysis was conducted as a basic research to establish a forecasting and warning system for flood risk areas in small mountainous basins in South Korea. The Danyang 1 Bridge basin located in Danyang-gun, Chungcheongbuk-do was selected as the study basin, and the watershed characteristic factors were calculated using Q-GIS based on the digital elevation model (DEM) of the basin. In addition, nine heavy rainfall events were selected from 2020 to 2023 using hydrometeorological data provided by the National Water Resources Management Comprehensive Information System. HEC-HMS rainfall-runoff model was used to analyze the runoff characteristics of small mountainous basins, and rainfall-runoff model simulation was performed by reflecting 9 heavy rainfall events and calculated basin characteristic factors. Based on the rainfall-runoff model, parameter optimization was performed for six heavy rain events with large error rates among the simulated events, and the appropriate parameter range for the Danyang 1 Bridge basin, a small mountainous basin, was calculated to be 0.8 to 3.4. The results of this study will be utilized as foundational data for establishing flood forecasting and warning systems in small mountainous basin, and further research will be conducted to derive the range of parameters according to basin characteristics.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.49-57
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• 2007

The purpose of this study is to analyze contemporary changes of landcover patterns and landscape structure in order to provide basic data and methods for sustainable management and conservation in Baekdu Daegan region using GIS and landscape indices. According to the results based on the pattern analysis of landcover changes using the change detection matrix between 1975 and 2000, addition on $3.6km^2$ became urbanized areas. Otherwise, $85.7km^2$ of forest area shift into agriculture($72.2km^2$) and grass area($10.1km^2$) for the vegetables in highland condition and stock farm. According to the landscape structure analysis using landscape indices, forest areas were unstable forest structures because of fragmentation. Thus, to improve forest ecosystem, significant amount of forest through a new forest management policy considering local environmental conditions are needed. And, the connectivity of forests in local regions should be considered as well.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.343-356
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• 2009

SCS method was applied to make the assessments of direct runoff according to land use changes in Jeju island. Land uses were obtained from 5 year-period remote sensing time series data from 1975 to 2000 which are provided by Water Management Information System (WAMIS). Hydrologic soil groups were categorized based on soil series of National Academy of Agricultural Sciences (NAAS), and permeable geologic structures such as Sumgol, Gotzawal and so on. The land uses of Jeju island are obviously characterized by urban-agricultural areas increases, and forest areas decrease. According to land use changes, curve number (CN) for Jeju island was consistently increased from 65.3 in 1975 to 69.6 in 2000. From 1975 to 2000, the amount of direct runoff and ratios increased due to CN changes. When the rainfall data in 1995 was applied to each year, the direct runoff amounts were $299.0{\sim}351.6\;mm$, and runoff ratios were $15.1{\sim}17.7%$. In the case of the application of the rainfall data in 2000, the direct runoff amounts were $136.9{\sim}161.5\;mm$, and runoff ratios were $9.7{\sim}11.5%$. Since direct runoff can be closely related to groundwater recharge and sustainable groundwater yield, the groundwater influence caused by land use changes or district exploitations should be considered for the reasonable water management and development in Jeju island.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.3
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• pp.75-88
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• 2016

In this study, we used the CLUE-s model to predict the future land-use change based on the urban growth scenario in South Korea. The land-use maps of six classes (water, urban, rice paddy, upland crop, forest, and grass) for the year 2008 were obtained from the Ministry of Environment (MOE), and the land-use data for 5-year intervals between 1980 and 2010 were obtained from the Water Resources Management Information System (WAMIS), South Korea. For predicting the future land-use change, the MOE environmental conservation value assessment map (ECVAM) was considered for identifying the development-restricted areas, and various driving factors as location characteristics were prepared for the model. The predicted results were verified by comparing them with the land-use statistics of urban areas in each province for the year 2008. The prediction error rates were 9.47% in Gyeonggi, 9.96% in Gangwon, 10.63% in Chungbuk, 7.53% in Chungnam, 9.48% in Jeonbuk, 6.92% in Jeonnam, 2.50% in Gyeongbuk, and 8.09% in Gyeongnam. The sources of error might come from the gaps between the development of political decisions in reality with spatio-temporal variation and the mathematical model for urban growth rate in CLUE-s model for future scenarios. Based on the land-use scenario in 2008, the land-use predictions for the year 2100 showed that the urban area increased by 28.24%, and the rice paddy, upland crop, and forest areas decreased by 8.27, 6.72, and 1.66%, respectively, in South Korea.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.549-556
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• 2017

Rivers continuously transport terrestrial organic carbon matter to the estuary and the ocean, and they play a critical role in productivity and biodiversity in the marine ecosystem as well as the global carbon cycle. The amount of terrestrial organic carbon transporting from the rivers to ocean is an essential piece of information, not only for the marine ecosystem management but also the carbon budget within catchment. However, this phenomenon is still not well understood. Most large rivers in Korea have a well-established national monitoring system of the river flow and the TOC (Total Organic Carbon) concentration from the mountain to the river mouth, which are fundamental for estimating the amount of the TOC flux. We estimated the flux of the total terrestrial organic carbon of five large rivers which flow out to the Yellow Sea, using the data of the national monitoring system (the monthly mean TOC concentration and the monthly runoff of river flow). We quantified the annual TOC flux of the five rivers, showing their results in the following order: the Han River ($18.0{\times}10^9gC\;yr^{-1}$)>>Geum River ($5.9{\times}10^9gC\;yr^{-1}$)>Yeongsan River ($2.6{\times}10^9gC\;yr^{-1}$)>Sumjin River ($2.0{\times}10^9gC\;yr^{-1}$)>>Tamjin River ($0.2{\times}10^9gC\;yr^{-1}$). The amount of the Han River, which is the highest in the Korean rivers, corresponds to be 4% of the annual total TOC flux of in the Yellow River, and moreover, to be 0.6% of Yangtze River.

• Journal of the Korean Geosynthetics Society
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• v.21 no.2
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• pp.31-38
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• 2022

Recently, irregular torrential rainfall have frequently occurred due to abnormal climate, and landslide damage is increasing. In Korea, more than 70% of the total land is mountainous areas, appropriate measures are needed to prevent landslides by heavy rainfall. When improved soil is applied to the surface of the slope, it is possible to suppress an increase in groundwater level due to rainfall penetration and secure stability of the slope. In this study, the appropriate depth of improved soil that can confirm the increase in groundwater level and secure stability by applying improved soil to the weathered soil slope was studied. A total of three cases were analyzed for the slope of the cross-section: standard slope for weathered soil (1:1.5, 1:1.8, and 1:2.0). For rainfall conditions, referring to the regional frequency probability rainfall provided by the Water resource Management Information System, the increase in groundwater level by stage was confirmed by assuming a 500-year frequency precipitation maximum duration of 48 hours. As a result of the study, in the case of natural slopes, the slope was completely saturated before 48 hours the rainfall duration, and there was a possibility of collapse. the improvement depth in the slope of 1:1.5 was appropriate for more than 1m from the surface regardless of the rainfall duration, and in the the slope of 1:1.8 was appropriate of 1m for more than 36 hours. in the slope of 1:2.0, it was appropriate for that safety when improved soil of 0.5m for rainfall duration 48 hours or more.