• 한국컴퓨터정보학회논문지
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• 제29권9호
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• pp.125-136
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• 2024

산사태 예방을 위한 비구조물 대책 중 하나로, 산사태 예·경보 시스템의 임계 강우 기준을 마련하기 위한 강우 특성 분석 자동화 알고리즘을 제안한다. 알고리즘은 파이썬으로 작성했다. 강수 자료는 기상청과 산림청의 관측소 정보를 활용하였고, 산사태 정보는 2020~2023년까지의 데이터를 기반으로 행정안전부의 생활안전지도를 통해 수집했다. 알고리즘은 3단계이다. 첫째, 강수 자료를 입력받아 지점 정보 불일치와 결측값을 정제한다. 둘째, 산사태 위치와 가장 가까운 관측소를 찾아내고, 무강우 기간 및 반감기를 고려하여 강우 사상을 분류하고 분석한다. 셋째, 강우 특성에 대해 기초 통계를 수행한 후, 적절한 통계 모델을 선정·분석한다. 분석 결과, 강우강도-지속시간, 유효 강우량-지속 시간, 선행강우량-지속 시간, 최대강우량-지속 시간의 관계에 대해 멱법칙과 비선형 회귀분석을 실시하였으며, 평균 R² 값이 0.45로 나타났다. 분석된 임계 강우 기준은 강우강도 0.9~1.4mm/hr, 유효강우량 68.5~132.5mm, 선행강우량 81.6~151.1mm, 최대강우량 17.5~26.5mm로 분석되었다. 기준 검증을 위해 AUC-ROC 분석을 수행한 결과, AUC 값이 0.5로 낮게 나타났다. 마지막으로 알고리즘의 속도 성능을 평가한 결과 총 30분의 시간이 소요되었다. 즉, 강우 자료만으로 재해를 예측하는 데에는 한계가 있음을 시사한다. 단, 재해로 인한 인명과 재산 피해를 막기 위해서는 정량적이나 해석이 편리한 방법으로 기준 선정이 필요하다. 따라서 본 연구에서 개발한 알고리즘을 활용하여 산사태 발생 임계 강우 기준의 정량적 평가를 통해 인명 및 재산 피해를 저감하는 데 기여할 수 있을 것으로 기대한다.

• 한국환경농학회지
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• 제25권4호
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• pp.306-315
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• 2006

강우에 의한 경사지 토양으로부터의 농약 유출양상을 파악하고 그에 대한 농약의 특성, 환경적 요인 및 영농방법 등의 영향 정도를 평가하기 위하여 토양흡착실험과 인공강우유출실험을 수행하였다. 흡착실험을 수행하여 농약의 이동 가능성과 이동형태를 파악하고 인공강우시설을 이용한 유출실험으로 강우양상 및 경사도의 영향 정도를 파악하여 농약의 표면유출에 의한 유실 수준을 평가하고자 하였다. 각 농약의 Freundlich 흡착계수 K는 ethoprophos $1.2{\sim}2.2$, alachlor $1.5{\sim}2.6$, ethalfluralin $56{\sim}94$ 및 pendimethalin $104{\sim}189$ 순이었다. 일반적인 흡착실험 방법인 용액에 존재하는 농약을 토양에 흡착시키는 방법보다 농약을 토양에 혼화처리한 후 탈착시키는 방법에서 흡착계수 값이 높았고, Freundlich 등온흡착식의 직선성을 나타내는 1/n 값은 탈착방법의 경우 $0.96{\sim}1.02$이었고 흡착방법의 경우는 $0.87{\sim}1.02$로 나타나 탈착방법에 의한 흡착계수 측정방법이 물질의 처리농도에 의하여 영향을 적게 받는 것으로 확인되었다. 영국 SSLRC의 이동성 분류기준으로 판단하면 alachlor와 ethoprophos는 moderately mobile$(75{\leq}Koc<500)$ 등급에 해당하였으며, ethalfluralin 및 pendimethalin은 Koc 4000을 초과하여 non-mobile 등급에 속하였다. 인공강우 처리구의 유출수 및 유실토양에 의한 농약 유실율은 각각 alachlor $1.0{\sim}6.4%$ 및 $0.3{\sim}1.2%,\;ethalfluralin\;1.0{\sim}2.5%$ 및 $1.7{\sim}10.1%,\;pendimethalin\;1.3{\sim}2.9%$ 및 $3.8{\sim}10.8%,\;ethoprophos\;0.6{\sim}2.7%$ 및 $0.1{\sim}0.3%$이었다. 인공강우실험 후 공약의 토심별 분포를 살펴 본 결과 alachlor와 ethopropho는 토심 $10{\sim}15cm$까지 이동하였고, ethalfluralin과 pendimethalin는 대부분 토심 5 cm 이내에 잔류하였다. 경사도 30%의 경우가 10%에 비하여 각 농약의 유실량이 $0.2{\sim}1.9$ 배 증가하였는데 유출수에 의한 농약의 유실량 차이는 유출수 중 농도 차이로 판단되며, 유실토양에 의한 농약 유실량 차이는 토양 유실량과 관계되는 것으로 생각되었다. 농약의 강우에 의한 유실은 복잡하게 작용하는 많은 환경적 요인에 의하여 영향을 받지만 정교하게 구성된 환경 시나리오에 의하여 예측 가능할 것으로 판단되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.693-697
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• 2009

Physically-based WEPP watershed version was applied to a watershed, located at Jawoon-ri, Gangwon with very detailed rainfall data, rather than daily rainfall data. Then it was validated with measured sediment data collected at the sediment settling ponds and through overland flow. The $R^2$ and the EI for runoff comparisons were 0.88 and 0.91, respectively. For sediment comparisons, the $R^2$ and the EI values were 0.95 and 0.91. Since the WEPP provides higher accuracies in predicting runoff and sediment yield from the study watershed, various slope scenarios (2%, 3%, 5.5%, 8%, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28%, 30%) were made and simulated sediment yield values were analyzed to develop appropriate soil erosion management practices. It was found that soil erosion increase linearly with increase in slope of the field in the watershed. However, the soil erosion increases dramatically with the slope of 20% or higher. Therefore special care should be taken for the agricultural field with higher slope of 20% or higher. As shown in this study, the WEPP watershed version is suitable model to predict soil erosion where torrential rainfall events are causing significant amount of soil loss from the field and it can also be used to develop site-specific best management practices.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.191-198
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• 2005

Slope failures during heavy rainfall have resulted in death of life and economic loss. In recent years, the research on slope damage assessment using Geographical Information System(GIS) has been actively carried out by researchers of several goverment organizations and schools. The researchers in Highway and Transportation Technology Institute (HTTI) of Korea Highway Corporation has developed the GIS database(DB), including highway, rainfalls, soil or rock geometry, types of damage, etc. and have been working on the damage assessment of highway slopes. The DB has been established and summarized in two different ways, such as highway routes and administrative districts. Grid of rainfall intensity generated by maximum rainfalls of each administrative district has been devloped. It shows good correlation of slope damage with heavy rainfalls. Most of damaged slopes were found in the amount of 100 mm to 300 mm rainfalls.

• Water Engineering Research
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• 제3권1호
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• pp.31-44
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• 2002

The effect of diurnal cycle, intermittent visit of observation satellite, sensor installation, partial coverage of remote sensing, heterogeneity of soil properties and precipitation to the soil moisture estimation error were analyzed to present the global sampling strategy of soil moisture. Three models, the theoretical soil moisture model, WGR model proposed Waymire of at. (1984) to generate rainfall, and Turning Band Method to generate two dimensional soil porosity, active soil depth and loss coefficient field were used to construct sufficient two-dimensional soil moisture data based on different scenarios. The sampling error is dominated by sampling interval and design scheme. The effect of heterogeneity of soil properties and rainfall to sampling error is smaller than that of temporal gap and spatial gap. Selecting a small sampling interval can dramatically reduce the sampling error generated by other factors such as heterogeneity of rainfall, soil properties, topography, and climatic conditions. If the annual mean of coverage portion is about 90%, the effect of partial coverage to sampling error can be disregarded. The water retention capacity of fields is very important in the sampling error. The smaller the water retention capacity of the field (small soil porosity and thin active soil depth), the greater the sampling error. These results indicate that the sampling error is very sensitive to water retention capacity. Block random installation gets more accurate data than random installation of soil moisture gages. The Walnut Gulch soil moisture data show that the diurnal variation of soil moisture causes sampling error between 1 and 4 % in daily estimation.

• 한국농공학회논문집
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• 제56권6호
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• pp.103-111
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• 2014

This study was to develop the flood analysis module (FAM) for implementation of a web-based real-time agricultural flood management system. The FAM was developed to apply for an individual watershed, including agricultural reservoir. This module calculates the flood inflow hydrograph to the reservoir using effective rainfall by NRCS-CN method and unit hydrograph calculated by Clark, SCS, and Nakayasu synthetic unit hydrograph methods, and then perform the reservoir routing by modified Puls method. It was programmed to consider the automatic reservoir operation method (AutoROM) based on flood control water level of reservoir. For a $15.7km^2$ Gyeryong watershed including $472{\times}10^4m^3$ agricultural reservoir, rainfall loss, rainfall excess, peak inflow, total inflow, maximum discharge, and maximum water level for each duration time were compared between the FAM and HEC-HMS (applied SCS and Clark unit hydrograph methods). The FAM results showed entirely consistent for all components with simulated results by HEC-HMS. It means that the applied methods to the FAM were implemented properly.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.120-125
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• 2000

This study analyzes agricultural water demand nationwide which calculated by the estimation system for agricultural water demand(ESAD) with the data are observed in the other Studies. The results are as follows. Maximum, minimum and average values of annual evapotranspiration in paddy in 1,767 boundaries covering all the country are estimated as 819.2mm, 595.2mm and 702.9mm respectively. In the case of transplant seeding, the annual effective rainfall is estimated as 834.7mm to 464.3mm, while the average is 635.3mm. The amount of effective rainfall is largest in case of transplant seedlings and then come watered direct seeding and dry direct seeding regardless of region. Maximum, minimum and average values of annual evapotranspiration in upland in 1,767 boundaries are estimated as 659.97mm, 129.3mm and 411.8mm respectively. The annual effective rainfall is estimated as 607.2mm to 68.3mm while the average is 257.4mm. infiltration ratio in paddy in 1,767 boundaries applied in ESAD is 5.06mm/day in average, varying from 12.0mm/day to 2.0mm/day. Applied conveyance loss is 12.8% in average, varying from 18.0% to 8.0%.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.311-323
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• 2019

The number of newly constructed traditional Korean houses, i.e., Hanoks, and light-frame buildings is increasing. However, related research is limited owing to the lack of awareness regarding safety evaluations. Therefore, this study conducted an outdoor exposure test to accurately evaluate wooden constructions. Spruce, pine, and fir (SPF) material was monitored for a year, wherein the SPF material was artificially dried under 18% moisture content, and its physical properties and color differences were measured once a month. Large differences were observed in the material's weight and moisture content, which are indexes sensitive to daily range and rainfall; however, no significant difference was found for other basic properties in the pre and post test results. Herein, $L^*$, $a^*$, and $b^*$ values represent color differences; these values exhibited a general decrease after the test. Such differences were attributed to the loss of lignin in the wood. The color difference value was high between the months of May and July, when the daily range and rainfall significantly fluctuated. Multiple regression analysis was performed on the $a^*$ value (redness indicator), daily range, rainfall, and ultraviolet index. The results indicated that the daily range influenced redness the most. According to the estimated regression equation, the daily range and redness are positively correlated. Based on the results, the types and influence of independent variables on color difference are expected to change as the wood's duration of outdoor exposure and the amount of data obtained both increase.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.126-126
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• 2022

Climate change has continued to impact meteorological factors like rainfall in many countries including Nigeria. Thus, altering the rainfall patterns which subsequently affect the crop yield. Maize is an important cereal grown in northern Nigeria, along with sorghum, rice, and millet. Due to the challenge of water scarcity during the dry season, it has become critical to design appropriate strategies for planning, developing, and management of the limited available water resources to increase the maize yield. This study, therefore, determines the quantity of water required to produce maize from planting to harvesting and the impact of drought on maize during different growth stages in the region. Rainfall data from six rain gauge stations for a period of 36 years (1979-2014) was considered for the analysis. The standardized precipitation and evapotranspiration index (SPEI) is used to evaluate the severity of drought. Using the CROPWAT model, the evapotranspiration was calculated using the Penman-Monteith method, while the crop water requirements (CWRs) and irrigation scheduling for the maize crop was also determined. Irrigation was considered for 100% of critical soil moisture loss. At different phases of maize crop growth, the model predicted daily and monthly crop water requirements. The crop water requirement was found to be 319.0 mm and the irrigation requirement was 15.5 mm. The CROPWAT 8.0 model adequately estimated the yield reduction caused by water stress and climatic impacts, which makes this model appropriate for determining the crop water requirements, irrigation planning, and management.

• 산업기술연구
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• 제36권
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• pp.57-63
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• 2016

In this study characteristics of debris flow landslide were investigated on the focus of debris flow disaster occurred by heavy rainfall in 2013 at Goeun-ri around Kaeryoung Mt. in Chuncheon-si. Appropriate method for estimating scale of debris flow was investigated by comparing those values from soil loss by Universal Soil Loss Equation, debris flow yield rate obtained by field survey of investigating debris flow path from initiation and erosion to deposition and other methods. As results of this study, it might be an opportunity of contributing to construct the data base for determining the size of erosion control facilities in future.