• 한국환경과학회지
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• 제20권7호
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• pp.857-872
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• 2011

The variation of groundwater level in Jeju Island is analyzed with the data of precipitation observed from 48 monitoring post and groundwater level observed from 84 monitoring wells during 2001 to 2009. The groundwater level rises in summer and falls in winter. The rise of groundwater level by precipitation is fast and small in the eastern region and slow and large in the western region. However, the speed of fall during the period of no rain is slower in the eastern region than in the western region. It tells that permeability is greater in the eastern region than in the western region. In this paper, we set up the base level of groundwater and calculate recharge volume between the base level and groundwater surface. During the period, the average recharge volume was $9.83{\times}10^9m^3$ and the maximum recharge volume was $2.667{\times}10^{10}m^3$ after the typhoon Nari. With these volume and the recharge masses obtained by applying the recharge ratio of 46.1%, estimated by Jeju Province (2003), the porous ratio over the whole Jeju Island is 16.8% in average and 4.6% in the case of maximum recharge volume just after typhoon Nari. A large difference in the two ratios is because that it takes time for groundwater permeated through the ground just after rain fall to fill up the empty porous part. Although the porous ratios over the whole Jeju Island obtained in this way has a large error, they give us the advantage to roughly estimate the amount of recharged groundwater mass directly from observing the groundwater level.

• 한국산림과학회지
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• 제104권3호
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• pp.403-410
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• 2015

이 연구는 토석류 위험지역 총 272개소에서 토석류 유출에 영향을 미치는 20개의 산림환경인자에 대하여 산림환경 특성을 분석하였다. 입지환경인자 중 토심은 하(30 미만), 방위는 서쪽사면, 표고는 200~300 m, 산지평균경사는 $25{\sim}30^{\circ}$, 토질은 사양토, 모암은 화성암, 사면형은 복합사면이 토석류 위험이 높은 것으로 나타났다. 강우환경인자 중 최대시우량은 50~100 mm, 1일최대강우량은 300 m 이상이 토석류 위험이 높은 것으로 나타났다. 또한 유역환경인자 중 계상평균경사는 $10{\sim}20^{\circ}$, 계상평균폭은 10 m 미만, 계상에 있는 토석의 양은 적음(계상구성물 중 20% 미만), 수계밀도는 $1km/km^2$이내, 산사태 발생 가능성이 있는 경사 $20^{\circ}$ 이상의 분포비율은 40~60%, 산사태 위험도 2등급 이상 비율은 40~60%, 유목이 있는 상태, 사방공작물 시설이 있는 경우, 임상환경인자 중 영급은 3영급, 소밀도는 밀, 임상은 혼효림 등의 인자가 토석류 위험이 높은 것으로 나타났다.

• 생태와환경
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• 제38권1호통권110호
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• pp.105-117
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• 2005

낙동강 수계의 최대 인공호인 안동댐 저수지에서 2002${\sim}$2004년 동안 홍수기의 수온성층 구조에 따른 고탁수의 유입특성과 시 ${\cdot}$ 공간적 변동을 조사하였다. 6월부터 수온성층이 형성되었으며 성층구조에 따라 유입 수괴의 이동경로가 결정되었고 고탁수의 유입에 의해 성층구조가 변하였다. 고탁수는 유입 시기와 수량에 관계없이 저수지 상류부에서는 심층류로 유입되었고 중류부에서 바닥으로부터 분리되어 중층 밀도류의 형태로 하류까지 이동하였다. 또한 중층 밀도류의 형성지점은 유입량과 시기에 따라 공간적으로 다소 차이가 있었다. 유입량에 의해 수온성층과 DO 분포가 변하였고, 시기에 따라 변수층에는 2개의 수온 급감층과 저산소층이 각각 존재하였다. 최하류까지 이동한 홍수량의 고탁수층은 상승류를 형성하여 수심 15 m 아래에서 최대 20 m 두께로 고탁수층을 형성하였다. 고탁수층은 저수지 바닥으로 침전되지 않았고 중층의 취수구를 통해 하류로 배출되었으며 가을 순환시기 이후 완전 소멸되었다.

• 환경위생공학
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• 제22권4호
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• pp.87-104
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• 2007

The objective of this study is to estimate the load of pollutants caused from the forest area among non-point pollutants within the Juam lake. The surveyed forest area was classified into broad-leaved, conifer, mixed and herbage area by forest tree type. Water quality and flux were investigated under rainfall and non-rainfall, respectively. Then, pollutant loading was evaluated by using the values of unit pollutant loading factor of each point and area of forest zone. Water quality analysis results of runoff by forest tree types were as follows. - Annual BOD, $COD_{Mn}\;and\;COD_{Cr}$ concentration of runoff in conifer area was high, and particle and biological recalcitrant compounds were flowed highly. - SS, T-N and T-P concentration was high in runoff from broad-leaved area, and biological degradable compounds was flowed. - Water quality of water from valley was maintained good under non-rainfall and could be utilized as fresh drinking water. Through water quality standard investigation, a countermeasure establishment was necessary to secure a good quality of drinking water - BOD, $COD_{Mn},\;and\;COD_{Cr}$ concentration of Bo-sung river was higher 1.5 times than other 2 streams, and because of high T-N, and T-P concentration in Songgwang stream, the management for this was necessary.

• 물과 미래
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• 제9권2호
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• pp.67-75
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• 1976

With 9 existng reservoirs selected in the Sab-Gyo River Basin, the sedimentation of the reservoirs has been calculated by comparing the present capacity with the original value, which revealed its reduced reservoirs capacity. The reservoirs has a total drainage area of 6,792 ha, with a total capacity of 1,204.09 ha-m, and are short of water supply due to reduction of reservoirs capacity. Annual sedimention in the reservcire is relation to the drainage area, the mean of annual rain fall, and the slop of drainage area. The results of obtained from the investigation are summarized as follow; (1) A sediment deposition rate is very high, being about $9.19{m}^3/ha$ of drainage area, and resulting in the average decrease of reservoir capacity by 19.1%. This high rate of deposition could be mainly attributed to the serve denvdation of forests due to disor derly cuttings of tree. (2) An average unit storage of 415.8mm as the time of initial construation is decreesed to 315.59mm at present, as resultting, we could'nt supply water at 566.24ha. (3) A sediment deposition rate as a relation to the capacity of unit drainage area is as follow; $Qs=1.43 (c/a)^{0.531}$ (4) A sediment deposition rate as a relation to the mean of annval rainfall is as follow; $Qs=672.61 p^{0.024}$ (5) A sediment deposition rate as a relation to the mean slop of drainage area is follow; $Qs=267.21 S^{0.597}$

• 한국대기환경학회지
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• 제5권2호
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• pp.42-54
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• 1989

This study was carried out to investigate the phenomena of acid precipitation. The pH value, electro conductivity and major anions (sulfate, nitrate and chloride) were measured by automatic acid rain monitor and ion chromatography at 5 points in Seoul area from Jan. to Dec. 1988. 1. The acidity of rainfall was in order winter (4.31) spring (4.77) fall (4.94) summer (5.31). Rainfall with a pH of less than 5.6 was appeared 83.2 percent. 2. The range of the highest appearence frequency rate both at Hannam-dong and Songsu-dong was from pH 4.6 to 5.0 and appeared 30.7 percent and 38.3 percent respectively, Bang-i-dong was 36.3 percent in the ranged from pH 4.1 to 4.5 and Guro and Ssangmun-dong were 26 percent and 30.3 percent in the ranged from pH 5.1 to 5.5 respectively. 3. The sulfate and nitrate ion concentration in earlier rainwater ranged from 0.1 ppm to 50.2 ppm and from 0.01 ppm to 15.8 respectively. The earlier rainwaters were generally more acidic than the after rainwaters. 4. The order of the major anion concentration in rainwater was $SO_4^{2-} > Cl^- > NO_3^-$ and the acidity of it was more effective by sulfate ion than others. The correlation between pH value and anions concentration was shown positive correlationship at Guro-dong and Bang-i-dong and negative correlation at Hannam-dong but not at the other sites.

• 한국안전학회지
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• 제27권5호
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• pp.211-218
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• 2012

Two experiment are planed to identify driver's safe driving behaviour by curve radius, road surface condition in curve section. At four-lane and two-lane road, conducted experiments are check on driver's feeling of safety that 30 subjects do not feel discomfort. And using the data from these experiments, this study compare physical speed (not slipping, fall our of the road) with safety driving speed(drivers felt a comfortable and safe speed) each curve radius and fiver road surface condition(drying, wet, rain, snow and ice). As a result, safe driving behaviour factors that are derived to curve radius of 100m units, five road surface conditions enable to represent quantitative analysis of driver's discomfort. This study will develop road design method and evaluation reflected ergonomic aspects.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2009년도 춘계학술대회
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• pp.35-43
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• 2009

The specific feature of trains as a means of transportation is that, on one side, at once they can carry big loads but, at the same time, if an accident occurs, it potentially leads to many human casualties or big material losses. Especially, train accidents caused by bad weather conditions result in many fatal losses of human lives and property. In Korea many railways run either in mountainous areas or along rivers thus making them especially susceptible to natural hazards. The types of damages inflicted by heavy rains resulting from rapidly changing meteorological conditions are diverse; and not only their scope is big but also they repeat regularly. Consequently, this study analyses the reasons why such effects of heavy rains on the railway conditions, damage to the railways caused by heavy rains or cases of stone fall as well as other types of accidents are not avoided. Study also, on the basis of laws related to movement in poor weather conditions and specifics of train braking, identifies systematic and technical problems and suggests and emphasizes new complex measures on their prevention.

• 한국환경보건학회지
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• 제31권6호
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• pp.467-474
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• 2005

The runoff characteristics of combined sewer overflow(CSO) in the urban area of Jeonju were investigated and analyzed by using the SWMM (Storm Water Management Model) and GIS. From August to November 2004, investigations on two rainfall events were performed and flowrate, pH, BOD, COD, SS, T-N and T-P were measured. these data were used for model calibration. Using GIS technique, watershed characteristics of study area were calculated. that is, divide into sub_basin, total width, slope, make soil map etc. On the basis of the measured data and the simulation results by SWMM, it could be known that the $80-90\%$ of pollution load are discharged in early-stage storm runoff. SMC(site mean Concentration) for combined sewer system area were BOD 28.1, COD 31.5, SS 186 ppm etc. this is shown that during the rain fall, high concentration of waste was loaded to receiving water. Unit loads of combined sewer system area were BOD 306, COD 410, SS 789, T-N 79, T-P 6.8 kg/ha/yr.

• 분석과학
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• 제23권2호
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• pp.161-164
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• 2010

지하수 연구를 위한 추적자로 삼중수소를 이용하기 위해서는 강우중 삼중수소 양을 알아야 하므로 본 연구에서는 2007년부터 2009년까지 대전에서 매 월 강우를 채집하여 삼중수소 함량변화를 분석하였다. 분석 결과 강우중의 삼중수소 양은 최소 4.2 TU부터 최대 18.6 TU의 변화를 보였으며 여름과 겨울에 삼중수소의 양이 감소하고 봄과 가을에 그 양이 증가하는 경향을 나타내었다. 강우중의 평균 삼중수소 양을 강우량과 연관한 가중평균을 구한 결과 $7.85{\pm}0.46\;TU$를 나타내었다.