• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.71-78
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• 2012

The habitat suitability is an important factor to estimate the distribution and size of the physical habitat in river. This suitability is also a key factor to decide the ecological flow discharge for the fish. For the ecological analysis in river, accurate values of habitat suitability index for various fishes are necessary. In general, fish habitat is affected by the physical factor of the flow depth and velocity as well as the chemical and biological factors of nutrient and attached algae. Thus, the condition of the fish habitat is expected to be changed with each watershed and tributary. In this study, the habitat suitability indices for fishes were proposed by using the field monitoring data in the rivers of the Han and Geum river watersheds. The proposed indices for three fishes are compared: Zacco platypus, Zacco temminckii, and Coreoleuciscus splendidus. The results show that Zacco platypus has a similar distribution of habitat suitability index in two watersheds. Zacco temminckii and Coreoleuciscus splendidus, however, have different distributions with watersheds. Also, for Zacco platypus, the developed indices at three tributaries of the Han river are compared: Cheng-mi stream, Dal stream, and Hong-cheon stream. The comparision shows that the index in the Cheng-mi stream is different with those in the other rivers. This is expected to be because of a high nutrient concentration at the Cheong-mi stream.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.83-94
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• 2012

Slopes are commonly formed both above and below roads located in mountainous terrain and along riversides. The Buk-sil site, a cut slope formed below the road, collapsed in October, 2010. A field investigation determined the causes of failure as improper drainage of valley water from the slope above the road and direct seepage of road-surface water. These factors may have accelerated the collapse via complex interaction between water and sub-surface structures such as bedding. Projection analysis of the site showed the possible involvement of plane, wedge, and toppling failure. Safety factors calculated by Limit Equilibrium Analysis for plane and wedge failure were below the standard for wet conditions. The wetness index, analyzed using topographic factors of the study area, was 9.0-10.5, which is high compared with the values calculated for nearby areas. This finding indicates a high concentration of water flow. We consider that water-flow control on the upper road is crucial for enhancing slope stability at the Buk-sil site.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.49-57
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• 2011

Water budget analysis in the groundwater system was conducted in order to understand water budget distributions in the ground water system in Geum-gang watershed. The annual amounts of precipitation, runoff, evapotranspiration, dam storage change and water supply over the sub-watershed in Geum-gang watershed were evaluated the residual groundwater from 2002 to 2006, based on the water budget considering inflow and outflow. Then we are able to expect residual groundwater of each sub-basin. According to the result of study, the year 2003 and 2006 were recorded the highest and the lowest precipitation value, respectively. Average run-off percentage against precipitation was 60.44%. Annual evapotranspiration in each of years didn't show the remarkable variations but the values were high in the lower reaches of the basin. The residual waters in Geum-gang basin were determined to be 133.36 in 2002, 77.64 in 2003, -19.40 in 2004, -82.25 in 2005 and -128.07 mm in 2006. The residual water in Geum-gang basin was high in the main and up stream such as Maepo. Also the residual water showed low distributions in Nonsan and Seokhwa.

• 한국공간정보시스템학회:학술대회논문집
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• 2007.06a
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• pp.111-116
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• 2007

현재 한강수계를 제외한 3대강 수계에서 수질오염총량관리제도가 의무제로써 시행되고 있다. 그러나 과학적 타당성과 외국의 성공사례들로 하여금 한강수계에 대해서도 수질오염총량제도를 의무제화 하려는 시도가 추진되고 있고 있는 실정이다. 이 제도가 한강수계에도 도입된다면, 한강권역에 포함되는 모든 지자체는 해당 유역에서 하천으로 유입되는 배출부하량을 할당받은 할당부하량 이하로 관리하여야만 정해진 유역의 목표수질을 달성할 수 있으며, 배출부하량 관리를 계획한데로 이행하지 못한 지자체는 범칙금 내지는 행정제재를 받게 된다. 따라서 체계적이고 과학적인 모니터링 및 분석 수단이 필요하다. 이 연구는 환경부 고시 한강기술지침에 의거하여 GIS를 이용하여 인천일대의 오폐수 발생부하량 및 배출부하량을 제시하고 과학적인 오염물질 삭감방안을 모색하는 것을 목적으로 진행되었다. 생활계, 산업계, 축산계, 양식계의 4 가지로 분류된 점오염원과 토지 이용 분류에 따른 비점오염원에 대한 각각의 발생부하량을 GIS를 통해 산정하고, 모든 오염원별로 처리경로를 고려하고 처리시설별, 방법별 삭감 효율을 반영하여 배출부하량을 산정하여 GIS상에서 제시하고 분석하였다. 인천일대는 인근지역에 비해 인구밀도가 높고 산업단지가 발달하여 생활계와 산업계 오염원에 의한 발생부하량 및 배출부하량이 많았으며, 특정 오염물에 대해서는 삭감 계획이 필요함을 확인할 수 있었다. 따라서 수질오염총량관리제도에 대비하고 실제 수질 개선을 위하여 본 연구의 결과를 바탕으로 수질관리를 위한 시스템의 보완 및 삭감계획의 수립에 관한 연구가 필요하다.알 수 있었다. 이상의 결과를 토대로 기존 압출추출방법과 초임계 추출 방법을 비교한 결과 $\gamma$-토코페롤의 농도가 1.3${\~}$1.6배 증가함을 확인할 수 있었다.게 상관성이 있어 앞으로 심도 있는 연구가 더욱 필요하다.qrt{F}}}{\pm}e_0$)에서 단정도실수 및 배정도실수의 역수 제곱근 계산에 필요한 평균 곱셈 횟수를 계산한다 이들 평균 곱셈 횟수를 종래 알고리즘과 비교하여 본 논문에서 제안한 알고리즘의 우수성을 증명한다. 본 논문에서 제안한 알고리즘은 오차가 일정한 값보다 작아질 때까지만 반복하므로 역수 제곱근 계산기의 성능을 높일 수 있다. 또한 최적의 근사 역수 제곱근 테이블을 구성할 수 있다. 본 논문의 연구 결과는 디지털 신호처리, 컴퓨터 그라픽스, 멀티미디어, 과학 기술 연산 등 부동소수점 계산기가 사용되는 분야에서 폭 넓게 사용될 수 있다.>16$\%$>0$\%$ 순으로 좋게 평가되었다. 결론적으로 감농축액의 첨가는 당과 탄닌성분을 함유함으로써 인절미의 노화를 지연시키고 저장성을 높이는데 효과가 있는 것으로 생각된다. 또한 인절미를 제조할 때 찹쌀가루에 8$\%$의 감농축액을 첨가하는 것이 감인절미의 색, 향, 단맛, 씹힘성이 적당하고 쓴맛과 떫은맛은 약하게 느끼면서 촉촉한 정도와 부드러운 정도는 강하게 느낄수 있어서 전반적인 기호도에서 가장 적절한 방법으로 사료된다.비위생 점수가 유의적으로 높은 점수를 나타내었다. 조리종사자의 위생지식 점수와 위생관리

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.223-233
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• 2007

For this study, we analyzed spatial and temporal patterns of trophic state and water quality over the period of $2002{\sim}2005$, using the water chemistry dataset obtained from the Korea Rural community & Agriculture corporation. Most reservoirs, based on TN, showed eutrophic (about 88% of the total). About 20% of agricultural reservoirs, based on TP, showed eutrophic after the criteria of OECD (1982), while 71% and 3% were Hesotrophic and oligotrophic, respectively. Seasonal variations were evident due to the intense monsoon rain during July${\sim}$August; conductivity, COD, SS, nutrients, and chlorophyll-${\alpha}$ (CBL) increased in the postmonsoon compared to the premonsoon. TP values had positive functional relations with conductivity, COD, and CHL values. COD and SS peaked during the intense monsoon. Mean values of TP and CHL values were two times greater in the intense monsoon than the weak monsoon. The increased TP was probably due to inorganic suspended solids from point and non-point sources during the monsoon. Ratios of TN : TP had strong in- verse relations ($R^2$=0.843, p<0.001, n=34) with TP, but not with TN (p>0.05, n=34). Log10-transformed CHL increased with TP in most P-limited reservoirs $(Log_{10}TP=0.5{\times}Log_{10}CHL+0.086)$. Similarity analysis, based TN, TP, and CHL showed that three groups were separated at 90% similarity level; One group was reservoirs with high salinity nearby the seawater, and the other two groups were reservoirs with a low salinity of the inland, and intermediate salinity, respectively.

• Korean Journal of Environmental Agriculture
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• v.21 no.4
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• pp.269-273
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• 2002

A 0.19 hectare stream water purification demonstration wetland was constructed and planted with cattails from April 2001 to May 2001. Some portions of its bottom surfaces adjacent to levees have a variety of slope of 1:4 $\sim$ 1:15 and two small open water areas were installed in the wetland. These make its shape closer to a natural wetlant Nitrogen removal was a major objective of the wetlant Waters of Sinyang Stream flowing into Kohung Esturiane Lake located southern coastal region of Korean Peninsula were pumped and funneled into it. Volumes and water quality of inflow and outflow were analyzed from July 2001 through December 2001. Average inflow and outflow were 120 $m^3/d$ and 112 $m^3/d$, respectively. Hydraulic retention time was about 3.1 days. Average nitrate and total nitrogen removal rate for the early stage of the wetlands were 85.8 $mg/m^2/day$, 171.4 $mg/m^2/day$ respectively. Full establishment of cattails within a few years can develope litter-soil substrates and supply available carbon sources beneficial to the denitrification of nitrate. These can lead to increases of the nitrate retention rate. Short circuiting and dead zone areas which might be occurred due to the close-to-nature layout of the wetland were not observed during the monitoring period.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.378-384
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• 2019

Red-eared slider, Trachemys scripta elegans, is one of the most famous species to disturb native ecosystems in the world. In South Korea, the species was imported as pet, and now it is found whole of the country. Recent, natural breeding and spreading of the turtle has been reported. In this paper, we investigated the environmental factors to affect the reproduction of T. s. elegans. We surveyed the distribution of the turtle in Jeju island, South Korea, between 2012 to 2017. We compared the land covers and climate of habitats from breeding sites and non-breeding sites. The species was found from 38 sites in Jeju island; 21 of breeding sites and 17 of non-breeding sites. The number of total and only adult turtles was significantly higher in breeding sites than non-breeding sites (P<0.05). In breeding site, the reproduction rate from the farmland was significantly higher than others(P<0.05). However, the rate of land covers was not significant in non-breeding site (P>0.05). The difference on the climate between breeding and non-breeding was not significant(P>0.05). Moreover, none of climate factors affected to reproduction of T. s. elegans(P>0.05). Our study showed that the land covers surrounding the habitats are more important than climate for reproduction of T. s. elegans in Jeju island. This result indicates investigating the habitat and surrounding is necessary for the control of reproduction and spreading of the introduced species.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.306-315
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• 2019

The estuary of the Han River constantly suffers from pollutants and pathogenic microorganisms which could cause serious damage to aquatic organisms living there. Despite of this potential risk, it is hard to find any reliable scientific reports on the status of reportable disease infection to the organisms living in this area. In this study, cyprinid fish and crustaceans in Jeonryu-ri, a region of the Han River estuary, were investigated for the infection by representative reportable communicable diseases(SVC, spring viraemia of carp; KHVD, koi herpesvirus disease; EUS, epizootic ulcerative syndrome; WSD, white spot disease) and parasites. Peripheral fish and primary freshwater fish were observed in Jeonryu-ri with cyprinid caught most frequently. Crustaceans were mostly marine species. No positive bands to any of the reportable diseases were produced in any of the fish and crustacean examined in this study by PCR. No trace of Clonorchis sinensis, a liver fluke potential threat to human health, was detected in any of fish samples. However, many fish were infected by metacecaria of other flukes, and other various parasites such as nematode, cestode, copepod, monosite and acanthocephalan. These results suggest that important aquatic organisms in the Han River estuary is not seriously polluted yet. However, it is important to keep monitoring the diseases since the water quality in this region is constantly changing, and devastating influence of infectious diseases is unpredictable. Further, it is required to expand monitoring area toward upstream and increase the number of fish for examination.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.333-339
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• 2019

The Red swamp crawfish Procambarus clarkii is native to the southern United States and inhibits all over the world including the United States, Asia, Africa and Europe. In Europe, it is known to disrupt ecosystems such as competition with native crayfish. In this study, habitats of red swamp crawfish were identified in Jiseok stream (15.5 km section) and Daecho stream (6.1 km section) of Youngsan river. A total 33 red swamp crawfish were captured. A female captured in Jiseok stream carried 215 newly hatched red swamp crawfish in her the burrow. As a result of the analysis of the habitat environment, the water temperature was ranged of 2.4~32.8℃, conductivity was 53.4~502.3 μS cm^-1 and DO was 0.74~22.64 mg L^-1. As a result of measuring HOBO, the temperature ranged from -9~48.1℃, showing a change of 57.1℃ throughout the year. The variation of the water temperature throughout the year from 2.9~33.9℃ was found to be 31℃. Red swamp crawfish have a high adaptability and a wide range of environmental resistance, and report a sharp increase in newly invaded areas, negatively affecting indigenous organisms. In addition, it can be used as a medium for the spread of diseases and parasites, so prompt investigation and research should be carried out.

• Journal of Animal Environmental Science
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• v.11 no.2
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• pp.89-96
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• 2005

To investigate the influence of livestock farm's wastewater on the near stream, the water quality of 3 different streams are analysed after seasons. In summer, the minimum T-N in the upper stream was 0.005 ppm and the maximum T-N in the down stream was 5.005 ppm. The phosphate was detected only in down stream of S2 point and was 0.5 ppm. COD was varied from 8 ppm in upper stream to 20 ppm in down stream. In fall, the T-N and the phosphate had shown similar results as that of in summer, however COD was varied from 3 ppm in upper stream to 6 ppm in down stream. In winter, the minimum T-N in the upper stream was 0.053 ppm and the maximum T-N in the down stream was 0.51 ppm. The phosphate was detected only in down stream of S2 point and was 0.5 ppm. COD was varied from 3 ppm in upper stream to 6 ppm in down stream. To be becoming fall and winter, the water quality of streams showed better than that of summer, and the wastewater from the livestock farms had little influence on the near streams.