• Proceedings of the Korean Society of Crop Science Conference
• /
• 1998.10a
• /
• pp.288-312
• /
• 1998

In Korea, chemical fertilizers and agricultural chemicals have had a significant impact on food production and these are today thought to be an indispensable part of modern agriculture. On the other hand, socioeconomical and IMF and WTO status in Korea are constant reminders of the vulnerability of our fossil fuel dependent agriculture. A new crop production system to improve economic, environmental and production efficiency must be exploited. Our particular concern has been given to an integrated cropping system involving recycling of crop residues, soil and N management, biological N fixation and multipurpose legumes. As a new integrated crop production system, a no-till direct-sown rice-vetch relaying cropping system has been proposed in this paper. The formulation of this system is based on the conception that N fertilizers being neither limitlessly available nor affordable, the current high-input crop production systems have produced troubled results severe labour shortage ill rural areas, balance of payment, environmental degradation and reduction of human health far exceed economic concerns. A natural and logical consequence is that long-term sustainability of agricultural systems must rely on the use and effective management of internal resources. Based on the information obtained throughout a series of experiments last years we have proved that the no-till direct-sown rice-vetch relaying cropping system dictates biological alternative which can augment, and in some cases replace, N fertilizers. Comprehensive discussions were made for the proposed system and it concluded that the system can offer an economically attractive and ecologically sound means of reducing external nitrogen input and improving the quality and quantity of internal resources, and consequently improving the farmers as well as the national returns.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.600-600
• /
• 2016

기후변화로 인한 가뭄 및 홍수 등의 이상 현상은 유역의 수자원에 미치는 영향이 크기 때문에 이에 대한 예측 및 적응방안을 마련하는 부분이 대두되고 있다. 따라서 본 연구에서는 유역의 수자원 관리를 위하여 단위유역에서의 수자원 취약성을 평가하고자 하였다. 평가 지표는 기후 및 사회 경제 환경적 측면을 고려하여 선정하였으며, 취약성 정의에 따라 수량 및 수질/수생태에 대하여 각각 노출, 민감도, 적응능력으로 구성하였다. 이후 다기준 의사결정기법(Multi-criteria Decision Making, MCDM) 중 TOPSIS(Technique for Order Performance by Similarity to Ideal Solution)를 적용하여 각각의 통합 취약성을 도출하였다. 지표 자료는 2010년을 기준으로 국가 통계 자료를 통해 수집하였으며, 유출량과 증발산량 자료는 준분포형 장기유출모형인 SWAT(Soil and Water Assessment Tool) 모형의 모의 자료(2005~2014)를 활용하였다. 또한, 지표에 대한 가중치는 전문가 설문조사를 통해 산정한 주관적 가중치(Subjective weight)와 수집된 자료를 통하여 산정한 객관적 가중치(Objective weight)로 구분하여 적용하였다. 인구 및 산업의 밀집도가 높은 한강권역에 대하여 표준단위유역(평균 $145km^2$)의 취약성을 평가하였으며, 각각의 취약성 우선 순위를 확인하였다. 수량 취약성의 경우에는 경기 강원북부와 충정도 일부 지역이 높은 것으로 나타났으며, 수질/수생태는 수도권 등 비교적 하류에 위치한 지역의 취약성 순위가 좀 더 높았다. 가중치 적용 방법에 따른 공간분포의 차이는 수질/수생태 취약성이 더 크게 나타나는 것을 확인할 수 있었다.

• Korean Journal of Agricultural Science
• /
• v.48 no.1
• /
• pp.103-117
• /
• 2021

The severe effects of climate change, such as global warming and the El Niño phenomenon, have become more prevalent. In recent years, natural disasters such as drought, heavy rain, and typhoons have taken place, resulting in noticeable damage. Korea is affected by droughts that cause damage to rice fields and crops. Societal interest in droughts is growing, and measures are urgently needed to address their impacts. As the demand for high-quality agricultural products expands, farmers have become more interested in water management, and the demand for field irrigation is increasing. Therefore, we investigated water demand in the irrigation of drought-vulnerable crops. Specifically, we determined the water requirements for crops including cabbage, red pepper, apple, and bean in four regions by calculating the consumptive water use (evapotranspiration), effective rainfall, and irrigation capacity. The total consumptive water use (crop evapotranspiration) estimates for Dangjin-si (cabbage), Yesan-gun (apple), Cheongyang-gun (pepper) in Chungnam, and Goesan-gun (bean) in Chungbuk were 33.5, 206.4, 86.1, and 204.5 mm, respectively. The volumes of groundwater available in the four regions were determined to be the following: Dangjin-si, 4,968,000 m³; Yesan-gun, 4,300,000 m³; Cheongyang-gun, 1,114,000 m³, and Goesan-gun, 3,794,000 m³. The annual amounts available for the representative crops, compared to the amount of evapotranspiration, were 313.9% in Dangjin-si, 29.5% in Yesan-gun, 56.1% in Cheongyang-gun, and 20.1% in Goesan-gun.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.264-264
• /
• 2015

최근 기후변화는 우리 삶에 다양한 영향을 미치고 있으며, 이에 따른 수문순환 변화 역시 자명하게 받아들이고 있다. 이에 따라 수자원 취약성 평가 및 대책에 관한 연구는 다양하게 진행되고 있는 실정이다. 하지만 국내의 경우 전체 유역에 대한 수자원 취약성 평가 연구는 부족한 실정이다. 따라서 본 연구에서는 국내 총 12 수계인 한강, 안성천, 금강, 삽교천, 영산강, 섬진강, 탐진강, 만경강, 동진강, 낙동강, 태화강, 형산강 유역에 대한 수자원 취약성 평가를 실시하였다. 평가 방법으로는 장기간에 걸친 다양한 토양의 특징, 토지이용, 관리상태의 변화에 따른 크고 복잡한 유역의 유출량을 추정하기 위해 개발된 SWAT(Soil and Water Assessment Tool) 모형을 이용하여 수문 모형을 구축하였고, 유출 관련 매개변수 최적화 작업은 SWAT-CUP 모형을 이용하였다. 최적화된 매개변수의 적용을 통해 각 유역별 유출량을 산정하였다. 그 결과 2009년과 2011년은 한강, 낙동강, 금강, 영산강순 이였으며, 2010년은 낙동강, 한강, 금강, 영산강순 이였다. 면적별 유출량인 비유량(specific discharge)을 산정한 결과, 2009년에는 영산강, 낙동강, 금강, 한강순 이며, 2010년에는 영산강, 금강, 낙동강, 한강순 이였으며, 2011년에는 금강, 한강, 영산강, 낙동강 순을 보였다. 또한, 인구당 유출량 산정 결과 2009년에는 영산강, 금강, 낙동강, 한강순 이며, 2010년에는 영산강, 금강, 낙동강, 한강순 이며, 2011년에는 영산강, 금강, 낙동강, 한강순 이었다. 이를 바탕으로 국내 총 12 수계에 대한 수자원 취약성을 산정해보았다. 대응변수는 이수의 수요 및 공급적인 측면에서 구분하였으며, 사회/경제, 물 이용, 환경, SWAT으로 구성하였습니다. 수자원 취약성 평가를 위해 다기준의사결정기법(MCDM, Multi-Criteria Decision Making) 중 하나인 TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution)기법을 사용하였다. 산정 결과 삽교천, 동진강, 형산강, 안성천, 섬진강, 만경강, 낙동강, 영산강, 태화강, 금강, 한강, 탐진강 순 이였다. 본 연구 결과는 향후 다중 공간에 구축한 고해상도 모형을 통해 국내 수문상황 진단 및 고해상도 미래 수문 시나리오 생산을 통한 수자원 관리에도 활용될 전망이며, 기후변화 취약성 평가를 위한 지표 개발에 이용될 예정이다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.43-43
• /
• 2020

보령댐은 충남 서부지역 8개 시·군에 생활용수와 공업용수를 공급하고 있는 중요한 수원으로 최근 우리나라에서 발생한 연속적인 가뭄으로 2015년에는 저수율이 7.5 %까지 감소하여 제한급수가 시행되었다. 본 연구에서는 가뭄으로 인한 물 공급 부족에 취약함을 보인 보령댐 유역(297.4 ㎢)을 대상으로 SWAT(Soil and Water Assessment Tool) 모델과 RCP(Representative Concentration Pathways) 시나리오를 활용하여 극한 기후변화 사상이 반영된 보령댐의 내한능력을 평가하였다. SWAT 모형을 활용하여 보령댐의 물수지를 모의하기 위하여 보령댐의 실측 유출량, 저수량, 방류량으로 보령댐 유입량과 저수량을 보정(2002~2004) 및 검정(2005~2007)하였으며, 실측 저수량을 기반으로 미래 댐 운영을 모의하였다. 검·보정 결과, 댐 유입량과 저수량의 PBIAS(%)는 -0.04, -0.09, NSE(Nash and Sutcliffe Efficiency)는 0.52, 0.96, RMSE(Root Mean Square Error)는 1.80 mm/day, 0.67 × 10⁶㎥로 분석되어 신뢰성 있는 모의 결과를 보였다. 보정된 SWAT 모형으로 가뭄 사상이 반영된 기후변화를 모의하기 위하여 APCC의 26개 CMIP5 GCM 시나리오를 SPI (Standardized Precipitation Index)와 연속 이론(Runs theory)으로 분석하여 6개의 극한 가뭄 시나리오 (RCP 4.5, 8.5 CMCC-CM, INM-CM4, IPSL-CM5A-MR)를 선정하였으며, 선정된 시나리오를 모형에 적용하여 가뭄 사상을 반영한 보령댐의 미래 내한능력을 평가하였다. 내한능력평가 및 분석 기간은 Historical(1980~1999; 1990s), Present(2000~2019; 2010s), 그리고 미래 기간 (2020~2039; 2030s, 2040~2059; 2050s, 2060~2079; 2070s, 2080~2099; 2090s)으로 나누었으며, 취약성(Reliability), 회복성(Resilience), 위험성(Vulnerability), 세 가지 지표로 내한능력 평가를 수행하였다. 평가 결과, 미래 취약성은 2050s IPSL-CM5A-MR 시나리오에서 0.803까지 감소하였으며, 회복성과 위험성은 2070s IPSL-CM5A-MR 시나리오에서 0.003, 3,567.6 × 10⁶㎥까지 감소하였다.

• Journal of the Korea Institute of Building Construction
• /
• v.23 no.4
• /
• pp.405-416
• /
• 2023

Recent seismic activities in countries like China and Turkey have underscored the widespread and severe damages that earthquakes can inflict globally. Being situated in a seismically active zone, South Korea can no longer regard itself as immune to earthquake hazards, necessitating the urgent adoption of proactive measures against such threats. The government has been proactive in evaluating, formulating processes, and methods for the seismic retrofitting of public buildings lacking in earthquake resistance. However, enforcement mechanisms for privately-owned apartment complexes are absent, and in the face of insufficient previous research and guidelines, preemptive measures for public safety remain alarmingly inadequate. With over 48% of residential structures in Korea aged over 30 years, and apartment complexes constituting more than 80% of these, the gravity of the situation is undeniable. This study deduces key factors for seismic retrofitting of apartment buildings like earthquake zones, soil type, building significance, aging degree, vulnerability, etc., based on building seismic design codes. It further proposes an algorithm for a more succinct and efficient determination of the priority of seismic reinforcements for apartment buildings.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1A
• /
• pp.155-162
• /
• 2006

This study presents the seismic risk assesment for an extradosed bridge with seismic isolators of lead rubber bearings(LRB). First, the seismic vulnerability of a structure and then the seismic hazard of the site are evaluated using earthquake data set and seismic hazard map in Korea, and then the seismic risk of the structure is assessed. The nonlinear seismic analyses are carried out to consider plastic hinges of bridge columns and nonlinear characteristics of soil foundation. The ductility demand is adopted to describe the nonlinear behavior of a column, and the moment-curvature curve of a column is assumed to be bilinear hysterestic. The fragility curves are represented as a log-normal distribution function for column damage, movement of superstructure, and cable yielding. And seismic hazard is estimated using the available seismic hazard maps. The results show that the effectiveness of the seismic isolators for the columns is more noticeable than those for cables and girders, in seismic isolated extradosed bridges under earthquakes.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.5C
• /
• pp.231-238
• /
• 2012

The rockbolt functions as a main support, which restricts enlargement of the plasticity area and increases stability in the original ground around tunnels, and prevents a second deformation of an excavated surface by supplementing vulnerability arising from opening of the excavated surface. System bolting is generally applied if ground conditions are bad. System bolting is generally installed perpendicular to the excavation direction in every span. If a place is narrow, or it is difficult to insert bolts due to construction conditions, it may be connected and used with short bolts, or installed obliquely. In this study, laboratory model tests were performed to analyze the effect of the ground being reinforced by inclined bolts, based on a bending theory that assumes that the reinforced ground is a simple beam. In all test cases, deflections and vertical earth pressures induced by overburden soil pressure were measured. Total of 99 model tests were carried out, by changing the installation angle of bolts, lateral and longitudinal distance of bolts, and soil height. The model test results indicated that when the installation angle of bolts was less than $75^{\circ}$, deflections of model beams tended to increase rapidly. Also, the relaxed load that was calculated by earth pressure was rapidly increased when the installation angle of bolts was less than $75^{\circ}$. However, the optimum installation angle of inclined bolts was judged to be in the range of $90^{\circ}{\sim}75^{\circ}$. Also, as might be expected, the reinforcement effect of bolts was increased when the longitudinal and lateral distance of bolts was decreased.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.90-96
• /
• 2013

This study was conducted to investigate a stability trend within 6 above average and 4 blow average erosion control dams, which were selected by The Korean Association of Soil and Water Conservation and were built in 1990s in Gyeonggi and Gangwon Province. The study was aimed to measure rebound hardness of upstream face, flood way and downstream face from those dams selected by using 'Concrete Test Hammer'. The main purposes of the study are selection of compression strength prediction equation and scope of wavelength, which successfully demonstrate non-destructive test results for erosion control dams. There is an opportunity to increase disaster prevention ability when stability vulnerability of concrete erosion control dam is detected in a timely manner. Results of the compression strength investigation express that there is a consistency with visual inspection of stability that has been processed by The Korean Association of Soil and Water Conservation. We concluded that a prediction equation, which was developed by Architectural Institute of Japan (AIJ), shows highest suitability in Korean erosion control dams when stability investigation is performed. The detailed criteria for the test result are 'stable', 'detail inspection required' and 'poor' for over 300 $kgf/cm^2$, 250~300 $kgf/cm^2$ and below 250 $kgf/cm^2$ respectively. Standards for stability of Korean erosion control dam and a compression strength prediction equation (that corresponds to the standards of the stability) should be established on the basis of chronological data of erosion control dam compression strength. Systematical approach for stability inspection that carries out remodeling or repair when problem on erosion control structures are detected through visual inspection and simple stability test, is necessary for the future disaster prevention.

• Korean Journal of Heritage: History & Science
• /
• v.43 no.1
• /
• pp.100-117
• /
• 2010

This study analyzed vegetation structure of natural monuments Koelreuteria paniculata community in search of a conservation and management plan. Plant sociological analysis of Koelreuteria paniculata community indicates that it can be classified into Achyranthes japonica subcommunity and Rhodotypos scandens subcommunity and Trachelospermum asiaticum var. intermedium subcommunity. While Koelreuteria paniculata community of Ahnmyeondo is composed of sub tree layer and herb layer, those of Pohang and Wando are composed of tree layer, Sub tree layer, shrub layer, herb layer. The results of tree vitality analysis showed that those in Ahnmyeondo appeared to be relatively low when compared to those in Pohang and Wando-gun. This can be understood in two different aspects: disease and insects vulnerability due to a relatively simple structure and lack of competitive species, and decreased vitality / natural branch losses due to crown competition arising from high density. The result of soil characteristics analysis showed that soil texture, soil pH, organic matter, $p_2O_5$, exchange positive ion were sufficient for tree growth while total nitrogen was not, so that discretion would be needed for fertilizer application. As there were damages of disease and inscet, but only for 10~15% of the entire area; it still requires consistent preconsideration. The study suggests the management methods for preservation of Koelreuteria paniculata community. First, securing designated areas is necessary in order to minimize environment deterioration due to surrounding development. Especially, for sections with decreased areas, expansion of designated areas through land purchase should also be considered. Second, artificial interference may affect the livestock. Therefore, monitoring of artificial interference is necessary, based on which protection projects must be conducted. Third, from analysis of young plants which influence the maintenance mechanisms of Koelreuteria paniculata community, a decrease compared to the prior year was observed; investigation is needed. Therefore, an active management policy through status examination of livestock such as germination and young plants is necessary.