• 전기의세계
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• v.18 no.1
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• pp.33-37
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• 1969

한전은 1968년 11월 3일 오전 10시 04분을 기하여 154KV 전계통의 직접접지방식 전환을 단행하였다. 종전의 P.C(소고선륜) 중성점접지방식을 직접접지방식으로 전환한것으로서 전력사상 특기 할 만한 근대화사업이며 다년간을 두고 추진해온 중요과제였다. 전력계통의 확대와 복잡화는 선진국가에서도 실시하고 있는 직접접지방식의 채택을 불가변하게 하였고 또한 1차 AID송배전차관도 이의 채택을 조건부로 승인되었던 것으로서 1968년 이후에 건설되는 송변전기기는 직접접지계에서만 운전할 수 있는 절연Level 650KV급이 도입되어 부산화력발전소 3호기가 준공되는 1968년 10월말까지는 직접접지전환이 반드시 이루어져야 하는 실정에 놓여 있었다. 그런데 직접접지방식의 단점인 인접통신선에 미치는 유도장해를 해결하는 문제가 다년간을 두고 진지하게 검토되어 왔으나 해결이 늦어지고 있었다. 사유는 154KV 계통에 인근된 통신선이라면 체신부, 내무부, 교통부, 국방부등 여러기관의 것이 있는데, 유도장해보안방법과 유도보상비문제에 대하여 전력측(상공부, 한전)과 통신측(상기의 체신부등)의 견해차가 해소되지 않기 때문이었다. 그것이 1968년 5월에 와서 전력.통신쌍방이 범국가적입장에서 제반애로를 무릅쓰고 최소한의 투자로 가능한 범위내의 보안책으로서 우선 Arrester 보안방식을 채택하기로 합의되어 경제장관회의를 거쳐 시공하기에 이른것이다. 이 란을 빌려 이 사업의 필요성과 경위및 통신선유도장해방지를 위한 보안방식내용을 간단히 소개함으로써 앞으로 이 분야의 항구적인 유도대책연구에 다소나마 참고가 된다면 다행으로 생각하겠다.면서 예측강우의 질이 저하되기 시작하였으나 QPM을 합성함으로써 생산한 BQPF는 보다 신뢰성있고 양호한 결과를 얻을 수 있었다. 이러한 결과들은 향후 정량적 분포형강우 예측을 이용한 실시간 홍수유출 예측시 댐운영자는 리드타임(홍수선행시간)을 충분히 확보함으로서 안정적이고 예측 가능한 홍수조절을 하는데 도움을 줄 수 있을 것으로 기대된다. 이와 같이 다양한 단기저수지 유입량의 예측정보 제공으로 다목적댐 저수지 운영모형의 효용성을 제고하여 향후 실제 저수지 유입량 예측에 이용함으로써 저수지 단기운영효율 개선에 기여할 수 있을 것으로 사료된다.다. 이것은 여름철 강수량이 증가하고, 호우발생빈도, 특히 8월의 강수일수가 증가하고 있다는 것과 밀접한 관련이 있다. 여름과 가을에 우리나라에 영향을 미치는 태풍의 수는 뚜렷한 추세를 보이지 않으나, 2002년 루사, 2003년 매미로 인하여 각각 6조원, 4조원 이상의 막대한 피해가 발생하였다. 태풍에 의한 피해액은 GDP 대비 약 0.9%(태풍 루사)로 최근 경제상장률과 비교해 보면, 상당한 비율을 차지한다. 우리나라에 영향을 미치는 태풍은 연근해의 해수면 온도가 높아지면 세기가 강해질 가능성이 높다. 폭설과 한파일수도 평년대비 최근 10년 감소하였고 일최저기온이 영하 $10^{\circ}C$ 이하인 날도 연간 발생일수가 감소하였다. 최근 10년간 우리나라 기후의 변화특성은 기온상승과 더불어 서리종료일이 앞당겨지고 열대야가 증가하고 폭설, 한파, 겨울철 일최저기온 영하 10도 이하인 날의 감소 등이 나타나고, 여름철 재해의 원인인 호우일수는 증가하는 추세이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.537-545
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• 2018

Determination of the time parameters such as the travel time in the design flood is very important. The travel time is mainly used for flood and river management, and the travel time of non flood season is used for maintenance flow and management of the river. Estimation of travel time for natural rivers is mainly based on the geomorphological factors of the basin. In addition to the topographical factors, the travel time is calculated by considering the factors of the runoff curve, velocity and rainfall intensity. However, there is no study on the estimation of travel time considering both the rainfall condition and the soil moisture accounting by the frequency period. Therefore, the travel time calculation is divided into the case of setting the Hwanggang Dam and the Imjin bridge water level station of Imjin river as the natural river considering rainfall condition by the frequency period and the soil moisture accounting, and the case of traveling the Imjin bridge water level station according to the condition of outflow of the Hwanggang Dam. For the sections set as natural rivers, the results were verified by comparing with the newly developed travel time calculation method. Based on the results, the travel times of the Hwanggang Dam outflow conditions were calculated. The time to travel in this study can be secured flood control of the Imjin river basin and time to prepare for danger when outflowing the the Hwanggang Dam.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.105-114
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• 2013

Recently, Due to Climate change, extreme rainfall occurs frequently. In many preceding studies, Because of extreme hydrological events changes, it is expected that peak flood Magnitude and frequency of drainage infrastructures changes. However, at present, probability rainfall in the drainage facilities design is assumed to Stationary which are not effected from climate change and long-term fluctuation. In the future, flood control safety standard should be reconsidered about the valid viewpoint. In this paper, in order to assess impact of climate change on drainage system, Future climate change information has been extracted from RCP 8.5 Climate Change Scenario for IPCC AR5, then estimated the design rainfall for various durations at return periods. Finally, the design flood estimated through the HEC-HMS Model which is being widely used in the practices, estimated the effect of climate change on the Design Flood of Mihochen basin. The results suggested that the Design Flood increase by climate change. Due to this, the Flood risk of Mihochen basin can be identified to increase comparing the present status.

• Korean Journal of Environmental Agriculture
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• v.24 no.2
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• pp.180-184
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• 2005

This study was peformed to assess environmental effect through rice culture with sewage irrigation using Iksan stream water from 2002 to 2003. Contents of $NH_4-N$ in irrigation water keep up one day at the tillering stage and panicle formation stage were decreased 40% and 52% respectively, but that of continued 4 days was decreased $88%{\sim}98%$. The $NH_4-N\;and\;NO_3-N$ in run off by reduction 50% fertilization were more decreased 17% and 44% respectively, than those of conventional fertilization level. Amount of K and $NO_3-N$ loss in infiltration water were more decreased 18% and 4% respectively, those of than conventional fertilization level. The Cu and Pb contents in soil of after experiment were slightly increased but other heavy metals were not accumulated. The rice yield by reduction 50% fertilization level was not significant compare with conventional fertilization level but head rice rate was increased.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1141-1155
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• 2013

A number of studies have been performed to analyze climate change impacts of water resources system. In this study, a coordinated dam operation is compared with an existing operation strategy for coping with projected future runoff scenarios. GCMs (Global Circulation Models) and the LARS-WG downscaling method was used to project future climate scenarios. The water balance model called abcd was employed to estimate future runoff scenarios. The existing dam operation comes from the national dam construction guideline, which is called the "level-operation method." The alternative coordinated dam operation are constructed as a linear programming using New York City rule for refill and drawdown seasons. The results of annual total inflow in future is projected to decrease to 72.81% for Andong dam basin and 65.65% for Imha dam basin. As a result of applying future runoff scenarios into the dam operation model, the reliability of coordinated dam operation, 62.22%, is higher than the reliability of single dam operation, 46.55%. Especially, the difference gets larger as the reliability is low because of lack of water. Therefore, the coordinated operation in the Andong & Imha dams are identified as more appropriate alternative than the existing single operation to respond to water-level change caused by climate change.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.667-673
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• 2011

There is relatively high vulnerability of soil erosion in slope highland agriculture due to a reclamation of mountain as well as low surface covering in early summer season with high rainfall intensity time. The aim of this study was to evaluate various surface covering methods for reducing soil loss in highland radish cultivation in highland. The experiment was conducted in 17% sloped lysimeter ($2.5m{\times}13.4m$) with 8 treatments including covering with cut rye, sod culture of rye, Ligularia fischeri var. spiciformis Nakai, Arachniodes aristata Tindale, Aster koraiensis Nakai, Festuca myuros L. and mulching with black polyethylene film, and runoff water, eroded soil and radish growth were investigated. Surface covering with sod culture and plant residue, especially cut rye treatment, had lower runoff water than non-covering, whereas black polyethylene film mulching had the reverse. The amount of eroded soil was also lowest in cut rye treatment, $0.3Mg\;ha^{-1}$, and increased in the order of rye sod culture, Ligularia fischeri var. spiciformis Nakai, Aster koraiensis Nakai, Festuca myuros L., Arachniodes aristata Tindale, black polyethylene film, and non-covering, $68.2Mg\;ha^{-1}$. The results showed that surface covering with sod culture or plant residue could be effective for reducing runoff water and soil erosion in the radish field, significantly in cut rye treatment. On the other hand, in sod culture of rye, Aster koraiensis Nakai and Ligularia fischeri var. spiciformis Nakai, radish yields were lower than in the non-covering. Unlike this, covering with cut rye, sod culture of Festuca myuros L. had similar radish yield to the non-covering radish yield. In conclusion, covering with cut rye and sod culture of Festuca myuros L. were beneficial for reduction of soil loss without decreasing in radish yield in highland sloped fields.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.2
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• pp.36-46
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• 2015

Integration of crop-livestock farming has been a problem-solving mode for abatement of environmental pollution and recovery of resources in recent years. The objectives of this study were 1) to suggest the customized integration of crop-livestock farming model reflecting the regional characteristics through in-depth analysis of case study and 2) to analyze the livestock nutrients flow in terms of three primary elements as nitrogen(N), phosphorous(P), and potassium(K). The personal interview and survey were carried out in 2012 for a total of 161 farms from four different regions(NS, NW, JJ, YC) in South Korea. The mass balance analysis was used to suggest and evaluate the models for two sites(JJ and YC). The results showed that NS and NW sites produced relatively more livestock manure than the sites of YC and JJ because of the regional differences in livestock numbers and urbanization. The models were suggested for the site JJ and site YC, and 'two track model(energy and resource recovery)' and 'dispersal type model' were assigned respectively. For the nutrient flows, the releasing P and K with new models had increased up to 7%, while N release had decreased down to 15% in both YC and JJ sites compared to the present treatment system. Estimated value showed that there was oversupply of N (719 ton/yr) and $P_2O_5$ (1,269 ton/yr) in YC and deficiency of N (671 ton/yr) and excessive $P_2O_5$ (32 ton/yr) in JJ respectively. Therefore, P runoff has to be considered an eutrophication occurs in rural small stream when an integration of crop-livestock farm system is applied into both sites.

• Journal of the Korean Geographical Society
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• v.51 no.4
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• pp.525-539
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• 2016

This study attempts to predict the changes in the spatial distribution of occupational employment in Korea by applying Markov Chain Model. For the purpose we analyze the job-related migration pattern and estimate the transition probability with the last six years job-related migration data. By applying the Chapman-Kolmogorov equation based on the transition probability, we predict the changes in the spatial distribution of occupational employment for the next ten years. The result reveals that the employment of professional jobs is predicted to increase at every city and region except Seoul, while the employment of elementary labor jobs is predicted to increase slightly in Seoul. In particular, Gangwon-do and Chuncheongdo are predicted to increase in the employment of all occupational jobs.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.623-631
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• 2011

In recent decade, the occurrences of typhoon and severe storm events are increasing trend due to the climate change. And the intensity of natural disaster is more and more stronger and the loss of life and damage of property are also increasing. Therefore, this study tried to understand the impact of climate change on urban drainage system for prevention and control of natural disaster and for this, we selected Gyeyang-gu, Incheon city as a study area. We investigated the climate models and scenarios for the selection of proper model and scenario, then we estimated frequency based rainfall in hourly unit considering climate change. The XP-SWMM model was used to estimate the future flood discharge on urban drainage system using the estimated frequency based rainfall. As a result, we have known that the study area will be overflown in the future and so we may need prepare proper measures for the flood prevention and control.

• Journal of Korea Water Resources Association
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• v.45 no.7
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• pp.675-684
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• 2012

Recently, a heavy rainfall under climate change causes the flood exceeded river's conveyance. Flood control methods under the limited river width are the increase of embankment, the construction of storage pockets and diversion channel, the dredging of river bed. Hwasun flood control reservoir of washland is designed as the storage pockets and the regulating gate for the control of water level. In this study, the propriety of design was investigated through hydraulic experiments for the circumstances to exclude the constant flood discharge during operation period. In the results, the over flow rate of side weir exceeded the flow of design and indicated to be able to discharge the designed flow in the regulating gate opened 1.1 m. The high velocity 7.1 m/s behind the gate has investigated to reduce under 3.3 m/s by the baffle block.