• 한국토양비료학회지
• /
• 제42권Spc호
• /
• pp.45-46
• /
• 2009

간척지 토양은 도시화와 산업화로 인해 잠식되는 농경지를 대체하는 식량공급원으로 간척지는 쌀 산업 외에 원예, 축산 등 다양한 생물산업 기반으로 활용되고 있다. 그리고 간척지 논농업(간척지 논 307만 ha)은 온실가스 저감 기능을 가지고 있으며 년간 논 1ha당 이산화탄소 흡수량 21.9t, 산소 공급량 15.9t으로 알려져 있다. 그러나 높은 염농도와 지하수위, 지하수 상승에 의한 재염화 현상, 토양 물리화학성과 배수 불량, 논의 경우 적정 유효토심은 50cm 정도이나 간척지 논 유효토심 20cm 이하로 유효토심이 매우 낮은 편이다. 또한 간척년대 경과할수록 제염은 되나 토양물리성 불량, 시비량 과다와 양분 불균형 발생으로 인하여 수분과 양분보유능 향상 토양관리 기술 개발 필요하다.

• 한국환경복원기술학회지
• /
• 제16권5호
• /
• pp.19-26
• /
• 2013

This study was carried out to provide preliminary data for increasing biodiversity in agricultural ecosystem and investigate availability of using Tubificidae spp. for environment-friendly agriculture through the survey of growth of Tubificidae spp. in flooded paddy fields during winter. We estimated the number of Tubificidae spp. in rice paddy where had been flooded during the previous winter in Ganghwa-gun, Suwon-si, and Hwaseong-si (Bongdam-eup and Paltan-myeon) between March and April from 2010 to 2012. During growing period of rice, the number of Tubificidae spp. was compared between flooded and non-flooded paddy field in Ganghwa-gun. As results, mean density of Tubificidae spp. in winter flooded paddy field was 7,235.5 $ind./m^2$ in Ganghwa-gun, 14,347.5 $ind./m^2$ in Suwon-si, 59,989.9 $ind./m^2$ in Bongdam-eup, and 2,610.6 $ind./m^2$ in Paltan-myeon. Mean density of Tubificidae spp. was the highest in flooded paddy fields of Bongdam-eup that was kept wet until rice harvest time and had shallow water. While mean density was the lowest in Paltan-myeon where had deep water and later flooded paddy field than others. In Ganghwa-gun, during growing period of rice, mean density of Tubificidae spp. in flooded paddy fields (171,109.0 $ind./m^2$) and flooded fallow paddy fields (321,084.2 $ind./m^2$) was much higher than non-flooded paddy fields (1,006.6 $ind./m^2$). Flooded paddy field during winter can help increase the number of Tubificidae spp. which can control weeds and enhance biodiversity in paddy fields for environment-friendly agriculture. Early flooding and shallow water of paddy fields could be a good agriculture practice to encourage the growth of Tubificidae spp..

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

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2023년도 학술발표회
• /
• pp.178-178
• /
• 2023

Drought and flooding have historically coexisted in Korea, occurring at different times and with varying cycles and trends. The drought indicators measured were (PDSI), (SPI), and (SPEI) in order to statistically analyze the annual or periodic drought occurrence and objectively evaluate statistical characteristics such as the periodicity, tendency, and frequency of occurrence of droughts in the Doam watershed. To compute potential evapotranspiration (PET), both Thornthwaite (Thor) and Penman-Monteith (PM) parameterizations were considered, and the differences between the two PET estimators were analyzed. Hence, SPIs 3 and SPIs 6 revealed a tendency to worsen drought in the spring and winter and a tendency to alleviate drought in the summer in the study area. The seasonal variability trend did not occur in the SPIs 12 and PDSI, as it did in the drought index over a short period. As a result of the drought trend study, the drought from winter to spring gets more severe, in addition to the duration of the drought, although the periodicity of the recurrence of the drought ranged from 3 years to 6 years at the longest, indicating that SPIs 3 showed a brief time of around 1 year. SPIs 6 and SPIs 12 had a term of 4 to 6 years, and PDSI had a period of roughly 6 years. Based on the indicators of the PDSI, SPI, and SPEI, the drought severity increases under climate change conditions with the decrease in precipitation and increased water demand as a consequence of the temperature increase. Therefore, our findings show that national and practical measures are needed for both winter and spring droughts, which happen every year, as well as large-scale and extreme droughts, which happen every six years.

• 한국토양비료학회지
• /
• 제45권1호
• /
• pp.9-15
• /
• 2012

This study was performed to produce basic data for silty reclaimed tidal lands and to develop techniques of environmentally-friendly utilization in agricultural system. We chose the two sites in Saemangeum reclaimed tidal lands, one (Site I) has been treated with cultivating green manure and conducting the desalinization process through submergence since April, 2007 and the other (Site II) has been under natural condition without artificial treatment. In situ and ex situ physic-chemical properties were determined and comparisons were made for soil profiles examined at these two sites in April 2009. Surface soil of Site I had lower EC and higher field saturated hydraulic conductivity than those of Site II, uncultivated land. Especially, exchangeable sodium content was lowest in Site I Ap1 layer than in other layers. This is probably due to flooding desalination and green manure cultivation. Besides, Ap1 and A2 layers of soil profile in Site I showed brighter soil color and more root observation than those of Site II. This is probably due to green manure cultivation. By the large, for high cash upland crops and intensive agricultural use of silty reclaimed tidal land, site-specific soil ripening such as flooding desalination and green manure cultivation could be useful.

• 한국환경복원기술학회지
• /
• 제4권4호
• /
• pp.56-63
• /
• 2001

This paper presents treatment efficiency and plant growth of a subsurface-flow constructed wetland system (23 m in length, 6.5 m in width, 0.65 m in depth) over one year after its establishment on floodplain of a stream in June 2000. An upper layer of 10 cm in depth was filled with course sand and the main biological layer of 50 cm depth with crushed stone with 8 - 15 mm in diameter. The system was planted with common reeds (Phragmites australis) grown on pots. Effluent discharged from a secondary-level treatment plant was funneled into it. Reed stems emerging in April 2001 grew up to 145.9cm until July 2001. The number of reed stems in July 2001 increased by about 11 times compared with that just after planting. The system was inundated seven times by storms over the monitoring period. Reeds were slightly bent after flooding, however they returned to almost upright standing in a couple of weeks. Small portion of inside slope of berm was eroded and the system surface had a sedimentation of 2 - 3 mm in depth. The average removal rates for SS, $BOD_5$, T-N and T-P was 73%, 70%, 53%, and 72%, respectively. The purification efficiencies for SS and $BOD_5$ were fairly good. The reduction rates for T-N was relatively low for the period of late fall through winter until early spring due to lower water temperature which retarded microbial nitrification and denitrification mechanisms. Reduction in the concentration of T-P during fall and winter was relatively higher than that during spring. Leach of phosphorous from plant litters lying on system surface and slight resuspension of precipitated phosphorous in substrates resulted in lower reduction for T-P in spring.

• 한국수산과학회지
• /
• 제30권3호
• /
• pp.340-348
• /
• 1997

1993년 1월 소조와 대조때 썰매네트로 돌산도 모래해안 쇄파대 1m 수심의 표층과 저층과 바닷가에서 옆새우 단각류를 채집해서 우점하는 세 종의 대상분포를 비교했다. 단각류는 표층보다는 저층과 바닷가에 많이 나타났다. Pontogenera rostrata와 Allorchestes anusta의 밀도는 저층과 바닷가에서 대조보다 소조때 높았으나, Synchelidium lenorostralum은 소조때 더 낮았다. P. rostrata는 밀물과 썰물에 따라 수평이동을 했으나, S. lenrostralum과 A. angusta는 수평이동을 하지 않았다. 다른 두 종과 달리 P. rostrata는 낮보다는 밤에 유의하게 많이 나타나, 밤에 활발히 이동하는 듯하다. P. rostrata는 밀물때 밤에는 평균해수면 (MSL) 위 100cm까지 나타나지만, 낮에는 MSL 위쪽에 나타나지 않았다 그러나, 썰물때는 낮과 밤 모두 MSL 부근부터 MSL 아래 150cm 사이에 분포했다. S. lenorostralum과 A. angusta는 썰물때만 나타났으며, 분포범위는 전자가 MSL 150cm보다 아래쪽, 후자가 MSL부근부터 MSL 아래 150 cm 사이였다. P. rostrata와 S. lenorostralum과 A. angusta의 최고 밀도는 각각 32, 26, 3마리/$m^2$였다. 그리고, 모래해안에 사는 단각류의 분포양상과 생활양식의 관계를 논의했다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.56-60
• /
• 2008

Increasing urban sprawl and climate changes have been causing unexpected high-intensity rainfall events. Thus there are needs to enhance conventional disaster management system for comprehensive actions to secure safety. Therefore long-term and comprehensive flood management plans need to be well established. Recently torrential snowfall are occurring frequently, causing have snow traffic jams on the road. To secure safety and on-time operation of the Bi-modal tram system, well-structured disaster management system capable of analyzing the urban flash flooding and snow pack melt/freezing due to unexpected rainfall event and snowfall are needed. To secure safety of the Bi-modal tram system due to torrential snowfall, the snow melt simulation capability was investigated. The snow accumulation and snow melt were measured to validate the SWMM snow melt component. It showed that there was a good agreement between measured snow melt data and the simulated ones. Therefore, the Bi-modal tram disaster management system will be able to predict snow melt reasonably well to secure safety of the Bi-modal tram system during the winter. The Bi-modal tram disaster management system can be used to identify top priority area for snow removal within the tram route in case of torrential snowfall to secure on-time operation of the tram. Also it can be used for detour route in the tram networks based on the disaster management system predicted data.

• Ocean and Polar Research
• /
• 제29권2호
• /
• pp.135-153
• /
• 2007

Temporal (seasonal) and spatial distributions and variations of various physico-chemical factors (salinity, temperature, pH, DO, COD, SPM, POC, silicate, DIP, DIN) in surface and bottom waters were studied in the coastal environment with typical macro-tidal range and monsoonal weather condition, Gyeonggi Bay, west coast of Korea. Spacial distribution patterns of these factors were generally similar to each other, and appeared to be inversely related to the distribution pattern of salinity, suggesting that water quality of the study area was primarily controlled by the physical mixing process of Han-River freshwater with nearby coastal seawater. During flooding season, silicate- and nitrogen-rich Han River water directly flowed into offshore as far as $20\sim30\;km$ from the river mouth, probably causing serious environmental problems such as eutrophication and unusual and/or noxious algal bloom, etc. Except the surface water during summer flooding season, high concentrations of nutrients appeared generally in dry season, whereas low values in spring, possibly because of the occurrence of spring phytoplankton bloom. On the other hand, nutrient flux through the estuary seems to be primarily depending on river discharge, sewage discharge and agricultural activities, especially during the rainy season. Also, nutrients in this coastal waters are considered to be supplied from the sediments of tidal-flats, which developed extensively around the Han-River mouth, especially during fall and winter of dry and low discharge seasons, possibly due to the stirring of tidal flat sediments with highly enriched pore-water nutrients by storm. And also, COD and DIN concentrations in the study area consistently increased during the last 20 years, probably because of agricultural activities and increasing discharge of industrial and domestic wastes.

• 한국토양비료학회지
• /
• 제42권5호
• /
• pp.355-363
• /
• 2009

간척조성지 밭작물 재배기술개발의 일환으로서 바이오에너지 생산을 위한 피마자와 유채를 공시작물로 하는 작부체계로 유지작물의 재배가능성을 검토하였다. 피마자의 생존개체율은 토양염농도 $4dS\;m^{-1}$에서 급격히 감소하는 경향을 보였고, 초장이 50% 정도 단축되는 토양염농도는 $4dS\;m^{-1}$으로 추정되었다. 유채의 초장생육이나 수량은 토양염농도가 증가할수록 감소하여 초장은 $6dS\;m^{-1}$일 때, 수량은 $2{\sim}2.5dS\;m^{-1}$의 범위에서 50%가 감소되는 것으로 추산되었다. 강우가 많은 계절에 재배되는 피마자는 염농도 뿐만 아니라 습해에도 약하여 배수가 불량한 영상강과 화옹 간척지에서 각각 0.8과 $6.5kg\;10a^{-1}$로 적었으나 배수가 좋은 이원 간척지는 $42kg\;10a^{-1}$로서 비교적 높은 경향이었다. 겨울작물인 유채는 비강우기간의 재염화가 심하였던 화옹 간척지에서 전혀 수량을 얻지 못하였으나 출현불량과 염농도의 변이가 심하였던 이원 간척지는 종실수량이 평균 $9kg\;10a^{-1}$로서 매우 낮았고, 염농도가 낮게 유지된 영산강간척지는 $332kg\;10a^{-1}$로서 높은 경향을 보였다. 결론적으로 서해안 간척지에서 피마자와 유채의 생육 및 수량성을 고려해 볼 때 토양염농도가 피마자 $4dS\;m^{-1}$, 유채 $3dS\;m^{-1}$ 이하로 관리되고, 침수피해가 없도록 배수관리가 된다면 유지작물재배가 충분히 가능할 것으로 판단되었다.