• 한국작물학회지
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• 제34권s02호
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• pp.66-80
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• 1989

Salt injury in rice is caused mainly by the salinity in soil and in the irrigated water, and occasionaly by salinity delivered through typhoon from the sea. The salt concentration of rice plants increased with higher salinity in the soil of the rice growing. The climatic conditions, high temperature and solar radiation and dry conditions promote the salt absorption of rice plant in saline soil. The higher salt accumulation in the rice plant generally reduces the root activity and inhibits the absorption of minerals of rice plant, resulting the reduction of photosynthesis. The salt damages of rice plant, however, are different from different growth stage of rice plants as follows: 1. Germination of rice seed was slightly delayed up to 1.0％ of salt concentration and remarkably at 1. 5％, but none of rice seeds were germinated at 2.5％. This may be due to the delayed water uptake of rice seeds and the inhibition of enzyme activity, 2. It was enable to establish rice seedlings at seed bed by 0.2％ of salt concentration with some reduction of leaf elongation. The increasing of 0.3％ salt concentration caused to the seedling death with varietal differences, but most of seedlings were death at 0.4％ with no varietal differences. 3. Seedlings grown at the nursery over 0.1％ salt, gradually reduced in rooting activity after transplanting according to increasing the salt concentration from 0.1％ up to 0.3％ of paddy field. However, the seedlings grown in normal seed bed showed no difference in rooting between varieties up to 0.1％ but significantly different at 0.3％ between varieties, but greatly reduced at 0.5％ and died at last in paddy after transplanting. 4. At panicle initiation stage, rice plant delayed in heading by salt damage, at meiotic stage reduced in grains and its filling rate due to inhibition of glume and pollen developing, and salt damage at heading stage and till 3 weeks after heading caused to reduction of fertilization and ripening rate. In viewpoint of agricultural policy the overcoming strategy for salt injury is to secure sufficient water source. Irrigation and drainage systems as well as underground drainage is necessary to desalinize more effectively. This must be the most effective and positive way except cost. By cultural practice, growing the salt tolerant variety with high population could increase yield. The intermittent irrigation and fresh water flooding especially at transplanting and from panicle initiation to heading stage, the most sensitive to salt injury, is important to reduce the salt content in saline soil. During the off-cropping season, plough and rotavation with flooding followed by drainage, or submersion and drainage with groove could improve the desalinization. Increase of nitrogen fertilizer with more split application, and soil improvement by lime, organic matter and forign soil addition, could increase the rice yield. Shift of trans-planting is one of the way to escape from the salt injury.

• 자원환경지질
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• 제38권6호
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• pp.633-642
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• 2005

동중국해 북부 대륙붕에 발달한 후기 홀로세 니질 퇴적체의 분포양상과 층서의 발달 특성을 밝히기 위해 고해상도 Chirp 탄성파 단면 자료를 이용하여 분석하였다. 고해상 탄성파 단면도상에서 음향기반암(기저 경계면 B)위에 2개의 퇴적층서(Unit 1과 2)가 나타나며 이들은 침식 경계면(중간 반사면 M)으로 경계된다. 하위 퇴적층서 Unit 1은 음향학적으로 평행 또는 준평행 반사층리와 수로 충진 퇴적상이 나타난다. 상위 퇴적층서 Unit 2는 반투명 내부 퇴적상과 7m 이하 퇴적두께의 렌즈형태로 발달해 있다. 시퀀스 층서분석으로부터 이들 퇴적층서는 마지막 저해수준 이후 형성되었다. 해침 퇴적체(Unit 1)는 최후 빙기동안 형성된 층서 경계면위에 바로 분포한다. 해침 퇴적체는 침식곡의 염하구 환경하에서 하천, 델타, 그리고 조간대 환경의 복합 퇴적물로 구성된다. 해침 퇴적체 바로 위는 침식 저지형의 최대 범람면이 나타난다. 최대 범람면위에 발달한 고해수준 퇴적체(Unit 2)은 저지대를 충진하는 니질 퇴적체로 구성된다. 니질 퇴적체는 제주도 남쪽 약 140km 떨어진 곳에 마치 태풍 같은 모양의 원형 형태로 수심 약 60-90m 사이에 집중적으로 발달해 있다. 이 퇴적체의 분포 면적과 부피는 각각 약 $3,200km^2$와 약 $10.7\times1109m^3$이다. 니질 퇴적체의 기원은 고황하와 양자강에서 배출된 부유퇴적물의 혼합기원으로 해석된다. 원형의 분포형태는 북부 동중국해에 발달한 반시계 방향의 와류 순환계로 인해 형성된 것으로 판단된다.

• 한국재난정보학회 논문집
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• 제14권3호
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• pp.352-359
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• 2018

연구목적: 본 연구는 급속히 진행되는 온난화로 인해 발생되는 예측 불가한 기상이변에 대한 사전 대응방안뿐 아니라 재난재해 위기 시 및 복구 중에도 도시의 기능을 유지하도록 하는 사후 회복과 안정성 방안을 제안하고자 한다. 연구방법: 기술적 관점과 사회적 관점에서 리질리언스 이론을 살펴보고 네덜란드의 리질리언트 정책과 전략을 통해 워터프론트 공간의 리질리언트 계획방안을 모색한다. 연구결과: 기후변화로 인한 해수면 상승과 홍수에 유연하게 대응하기 위한 지역 특성에 따른 예방계획 및 재해 후 도시기능 유지방안과 재해재난 위험을 고려한 공간계획 수립 및 홍수위험수준을 고려한 계획방안은 워터프론트 이용을 위한 토지이용과 사회적 성장 동반, 지역특성을 고려한 재난재해 취약성을 고려한 계획, 재난재해위험을 고려한 물관리 계획 등이다. 결론: 도시공간을 창출함에 있어 기존의 공간계획방식을 넘어 이상기후에 대응한 새로운 도시개발방식이 필요하며, 특히 기후변화에 가장 취약한 워터프론트의 공간적 특성에 따른 리질리언스 전략이 요구된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.145-145
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• 2018

Small islands rely heavily on groundwater resources in addition to rainwater as the source of freshwater since surface water bodies are often absent. The groundwater resources are vulnerable to sea level rise, coastal flooding, saltwater intrusion, irregular pattern of precipitation resulting in long droughts and flash floods. Increase in population increases the demand for the limited groundwater resources, thus aggravating the problem. In this study, the effects of climate change on Tongatapu Island, Kingdom of Tonga, a small island in Pacific Ocean, are investigated using a sharp interface transient groundwater flow model. Twenty nine downscaled General Circulation Model(GCM) predictions are input to a water balance model to estimate the groundwater recharge. The temporal variation in recharge is predicted over the period of 2010 to 2099. A set of GCM models are selected to represent the ensemble of 29 models based on cumulative recharge at the end of the century. This set of GCM model predictions are then used to simulate a total of six climate scenarios, three each (2010-2039, 2040-2069, and 2070-2099) under RCP 4.5 and RCP 8.5. The impacts of predicted climate change on groundwater resources is evaluated in terms of freshwater volume changes and saltwater ratios in pumping wells compared to present conditions. Though the cumulative recharge at the end of the century indicates a wetter climate compared to the present conditions the large variability in rainfall pattern results in frequent periods of groundwater drought leading to saltwater intrusion in pumping wells. Thus for sustaining the limited groundwater resources in small islands, implementation of timely assessment and management practices are of utmost importance.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.169-169
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• 2020

According to the IPCC analysis, severe climate changes are projected to occur in Korea as the temperature is expected to rise by 3.2 ℃, the precipitation by 15.6% and the sea level by 27cm by 2050. It is predicted that the occurrence of abnormal climate phenomena - especially those such as increase of concentrated precipitation and extreme heat in the summer season and severe drought in the winter season - that have happened in Korea in the past 30 years (1981-2010) will continuously be intensified and accelerated. As a result, the impact on and vulnerability of the water management sector is expected to be exacerbated. This research aims to predict the climate change impacts on streamflow of Daecheong Lake area of Geum River in South Korea during the summer and winter seasons, which show extreme meteorological events, and ultimately develop an integrated policy model in response. We projected and compared the streamflow changes of Daecheong Lake area of Geum River in South Korea in the near future period (2020-2040) and the far future period (2041-2060) with the reference period (1991-2010) using the HEC-HMS model. The data from a global climate model HadGEM2-AO, which is the fully-coupled atmosphere-ocean version of the Hadley Centre Global Environment Model 2, and RCP scenarios (RCP4.5 and RCP8.5) were used as inputs for the HEC-HMS model to identify the river basins where cases of extreme flooding or drought are likely to occur in the near and far future. The projections were made for the summer season (July-September) and the winter season(November-January) in order to reflect the summer monsoon and the dry winter. The results are anticipated to be used by policy makers for preparation of adaptation plans to secure water resources in the nation.

• 한국환경과학회지
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• 제14권9호
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• pp.817-825
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• 2005

The purpose of this study was to research about salt marsh flora and vegetation in the Dongjin-river estuary area where has a project for Sea Man Geum Reclaimed Land so that we can foster foundation on restoration of an ecological habitat, development of applicable plant and establishment of a conservation policy after deceloping the reclaimed land for salt marsh vegetation which has great value ecologically. In conclusion, we was distributed that there are 7 families 21 genera, 25 species, 2 varieties of vascular plant at the Dongjin-river estuary area which have 27 taxa in total and are $0.64\%$ among 4,191 of korean vascular plant. There are also 2 family, 2 genus, 2 species of a naturalized plant which are $1.1\%$ of indicator of a naturalized plant salt marsh vegetation of the downstream are very much affected by the time of inundation, tidal water so that a low degree of salt marsh has frequent flooding by sea water and has a pure group of Suaeda japonica. A Phragmites communis, Carex scabrifolia are distributed mainly around a waterway of salt marsh and Zoysia sinica, Atriplex subcordata, Phragmites communis are living in stock as forming into patch around medium salt marsh. Suaeda asparagoides, Phacelurus latifolius are living around a little high ground and a Phragmites communis is a behind vegetation of Phacelurus latifolius and a part of the Phragmites communis are living along with waterway in a salt marsh as a community. By the 2-M method twelve plant communities were recognized ; Suaeda japonica. Carex scabrifolia, Zoysia sinica, Artemisia scoparia, Phacelurus latifolius, Phragmites communis, Suaeda maritima, Suaeda japonica-Atriplex gmelini, Phragmites communis-Suaeda japonica, Suaeda japonica-Salicornia herbacea, Salicornia herbacea-Suaeda aspar-agoides and Scirpus planiculmis community. The actual vegetation map was constructed on the grounds of the communities classified and other data.

• 대한조선학회논문집
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• 제56권1호
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• pp.34-46
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• 2019

This paper provides the numerical results for the self-propulsion performance in waves of a car ferry vessel with damage in one of its twin-screw propulsion systems without flooding the engine room. The numerical simulations were carried out according to the Safe Return to Port (SRtP) regulation made by the Lloyd's register, where the regulation requires that damaged passenger ships should have an ability to return to port with a speed of 6 knots in a Beaufort 8 sea condition. For the validation of the present numerical analysis study, the resistance performance and the self-propulsion performance of the car ferry in intact and damaged conditions in calm water were calculated, which showed a satisfactory agreement with the model test results of Korea Research Institute of Ship and Ocean engineering (KRISO). Finally, the numerical simulation of self-propulsion performance in waves of the damaged car ferry ship was carried out for a normal sea state and for a Beaufort 8 sea state, respectively. The estimated average Brake Horse Power (BHP) for keeping the damaged car ferry ship advancing at a speed of 6 knots in a Beaufort 8 sea state reached about 47% of BHP at MCR condition or about 56% of BHP at NCR condition of the engine determined at the design state. In conclusion, it can be noted that the engine power of the damaged car ferry ship in single propulsion condition is sufficient to satisfy the SRtP requirement.

• 한국물환경학회지
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• 제34권5호
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• pp.447-461
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• 2018

To realize river restoration that ecological characteristics of the river are reflected, we classified the river into four reaches of valley stream, upstream, midstream, and downstream based on substrate as well as riverbed gradient obtained from the relationship between distance from the river mouth, and above sea level. Considering that the rivers of Korea have been dominated by various and intense artificial interferences over a lengthy period, we determined cross sectional range of the river based on the geological map and clarified transformation degree by reach. Vegetation profile diagram was prepared by depicting horizontal range and vertical stratification of major vegetation appearing in a belt transect of 10 m breadth installed between weirs constructed in both sides of the river. Restoration models by river reach were prepared based on breadth of waterway, bare ground, herb, shrub, and tree dominated vegetation zones on vegetation profiles wherein a flooding regime was reflected. Species composition information collected from vegetation established in each zone was systematized to use for restoring each reach ecologically. Further, background that longitudinal reaches and horizontal zones were divided, was discussed by comparing with case studies in foreign countries. In addition, necessity of ecological restoration of the river was discussed based on degree of integrity of Korean rivers, ecological significance of riparian vegetation, and importance of reference information for ecological restoration of the river.

• 한국해양학회지:바다
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• 제19권2호
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• pp.131-146
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• 2014

남해대륙붕 가막만의 현생퇴적층 음향특성과 분포양상을 조사하기 위해 고해상도 탄성파 자료와 퇴적물을 분석하였다. 표층퇴적물의 입도는 주로 $6.3{\sim}9.7{\Phi}$의 분포를 보인다. 퇴적물은 니질과 실트로 구성되어 있으며, 내만으로 갈수록 입도가 감소한다. 고해상도 탄성파 자료에서 나타나는 가막만의 층서는 하부 경계면인 음향기반암 위로 2개의 퇴적층서(GB I과 II)로 구성되며 이들 층서는 중간 반사 경계면(최대해침면)에 의해 구분된다. 매우 불규칙한 형태를 보이는 음향기반암은 일반적으로 해수면 아래 약 20 m에서부터 최대 40 m 깊이에서 나타나며, 남쪽으로 갈수록 깊어진다. 하부층인 GB I은 수로를 피복하는 형태로 발달하고 있으며 무층리 반사 특징을 보인다. 이는 후기 해침동안 퇴적된 해침퇴적계열(TST)로, 조간대환경 퇴적층으로 해석할 수 있다. 최대해침면은 평균 해수면 아래 약 15 m에서부터 28 m 깊이에서 나타나며, 탄성파 단면상에서 편평하고 연속적인 반사면으로 나타난다. 최대해침면 위에 놓여있는 GB II는 투명 혹은 반투명한 음향특성, 그리고 평행한 반사 층리로 구성되며, 해수면이 현재의 위치에 도달했던 지난 6,000년 이후에 퇴적된 고해수면 퇴적계열(HST)로 해석된다. 특히, GB II 퇴적층은 고해수면 반사 경계면에 의해 2개의 층(GB II-a and II-b)으로 세분화되며 이는 바람, 해수 유동량, 그리고 조류에 의해 구분된 것으로 생각된다.

• 한국지리정보학회지
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• 제9권1호
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• pp.56-65
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• 2006

복하천 유역에서 홍수에 의한 침수피해가 자주 발생하였으며, 침수된 지역에서는 사면에서 유실된 토양에 의한 피해가 동반되었다. 복하천 유역의 토양유실 피해와 경작지의 상관성을 분석하고자, GIS를 이용하여 유역별 토양유실량을 산정하고자 하였다. GIS상에서 범용토양유실공식(USLE)을 이용하여 토양유실량을 산정하였고, 지형을 토대로 소유역을 구분하고 각 소유역의 단위토양유실량을 산정하였다. USLE에의해 산정된 단위토양유실량은 연평균강우량 1,329 mm/yr를 기준으로 0.03 ton/ha로 나타났다. 단위토양유실량이 가장 높게 나타난 지역은 백사면 상용리일대 소유역(0.05 ton/ha)으로, 유실위험이 높게 나타나는 소유역은 주로 경작지 활용율이 높은 지역으로 나타났다.