• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.157-161
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• 2007

Nutrients were investigated for surface water, bottom sediment and ground water in a rural watershed from January 2006 to March 2007. The concentrations of TN and $NO_3-N$ in ground water were higher than those in surface water due to fertilization on cabbage upland neighboring a river during March to August, but lower than those in surface water during September to February. However, the concentrations TP and $PO_4-P$ in ground water were lower than those in surface water. The concentrations of TP and $PO_4-P$ in surface water was lower than those in bottom sediment. The TP concentration in the bottom greatly decreased during rainy season. due to flush sediment of bottom, and then gradually increased.

• Ocean Science Journal
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• 제43권1호
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• pp.9-16
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• 2008

Environmental qualities of coastal water and bottom sediment were assessed at Jordan's northernmost tip of Gulf of Aqaba to evaluate possible impacts of the bordering fish pen cages in Eilat. Results showed significant differences between surface and bottom water in the chemical and physical variables in the different months of the year (2004-2005). Chlorophyll a was also significantly higher in bottom water when compared to that of the offshore water. Nitrate and ammonia were significantly higher in bottom water than the surface water at each individual station. The upper 2 cm of sediment sample recorded higher values of total phosphorus and organic matter. Seasonality affected the content of total phosphorus, organic matter, redox potential and color especially at the sediment layer below 3 cm of the sediment core. The present investigation showed slight modification of water and sediment qualities but no clear sign of eutrophication was observed. However, to maintain sustainability of healthy environmental conditions at the northern tip of Gulf of Aqaba potentials of any possible environmental risks arising from the fish farms or any other coastal investment should be carefully considered.

• Environmental Engineering Research
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• 제15권1호
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• pp.41-48
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• 2010

This paper describes the influence of nutrient salts eluted from the bottom of a closed water area where polluted sediment has been deposited by inflowing river water. The elution pattern was monitored at our experimental facility. Both the sediment pore water and water above the bottom were sampled using a dialyzer sampler (peeper). The pore water of the eutrophicated sediment contained a large amount of nutrient salts, and the effect of elution was confined to a limited area of the bottom surface. The nutrient concentration of the sediment pore water was closely related to both the water temperature and dissolved oxygen (DO) concentration. The eluted nutrients from the sediment provided a source for phytoplankton and algae growth. This experimental data indicated that the water quality of the surface was not directly connected to the eluted nutrient salts, while it was indirectly affected by the total ecosystem, including all the organisms within an area and their environment.

• 한국수산과학회지
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• 제27권2호
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• pp.200-214
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• 1994

진해만의 저서동물 군집생태 연구의 일환으로 저서환경의 특성을 구명하기 위하여, 1987년 6월부터 1990년 5월까지 12개 정점에서 표층 및 저층수의 수온, 염분, 용존산소와 퇴적물의 입도조성 및 유기물량을 조사하였다. 진해만의 저서환경은 내만으로 들어 갈수록 퇴적물 입도의 세립화, 높은 유기물함량, 여름철 성층의 발달로 인한 저층 빈산소 수괴의 형성 등이 특징적으로 나타났다. 저층의 빈산소수괴는 5월부터 내만에서 형성되기 시작하여, 여름철로 접어들면서 점차 외해역으로 확산되어 9월에 최고에 달하였으며, 진해만 전 해역의 절반이상이 빈산소 영향을 받고 있는 것으로 나타났다. 이러한 저층의 빈산소 환경은 가을철로 접어들면서 성층의 점진적 소멸과 함께 회복된다. 저층수의 수온, 염분 및 용존 산소량과 퇴적물의 입도 및 유기물 함량의 5개 환경요인에 대하여 주성분 분석을 실시한 결과 4개 해역으로 나눌 수 있었으며, 이러한 공간 분포는 전반적으로 퇴적물의 유기물함량과 가장 높은 상관관계를 가지는 것으로 나타났다.

• The Journal of the Acoustical Society of Korea
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• 제25권2E호
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• pp.60-68
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• 2006

High-frequency bistatic scattering measurements from a corrugated surface were made in an acoustic water tank. First the azimuthal scattering pattern was measured from an artificially corrugated surface which has varying impedance. The corrugated surface was installed both transverse to the direction of incident wave and longitudinal to the direction of incident wave. The angle between the corrugated surface and the direction of the incident wave was about $45^{\circ}$. Second, the scattering strengths were measured from the flat sediment and the corrugated sediment. A critical angle of about $37^{\circ}$ was calculated in the acoustic water tank. The measurements were made at three fixed grazing angles: $33^{\circ}$ (lower than critical angle), $37^{\circ}$ (critical angle), and $41^{\circ}$ (higher than critical angle). The scattering angle and the grazing angle are equal in each measurement. Frequencies were from 50 kHz to 100 kHz with an increment of 1 kHz. The corrugated sediment was made transverse to the direction of the incident wave. The first measurement indicates that the scattering patterns depend on the relations between the corrugated surface and the direction of the incident wave. In the second measurement, the data measured from the flat sediment were compared to the APL-UW model and to the NRL model. The NRL model's output shows more favorable comparisons than the APL-UW model. In case of the corrugated sediment, the model and the measured data are different because the models used an isotropic wave spectrum of sediment roughness in the scattering calculations. The isotropic wave spectrum consists of $w_2$ and ${\gamma}_2$. These constants derived from sediment names or bulk size. The model which used the constants didn't consider the effect of a corrugated surface. In order to consider a corrugated surface, the constants were varied in the APL-UW model.

• 한국수산과학회지
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• 제24권1호
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• pp.31-38
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• 1991

여수해만 광양만 입구의 조류 및 부유 퇴적물 함량 분석을 통하여 광양만 내의 부유 퇴적물 수지 균형을 조사하였다. 만 입구의 부유 퇴적물 함량은 바닥이 평균 약 17.80mg/l로 표층의 평균 약 4.75mg/l에 비해 상당히 높으며, 조류도 표층 부근에서는 썰물이 강하나 저층에서는 오히려 밀물이 강하여 유속의 비대칭 현상을 보이고 있다. 이러한 저층의 높은 부유 퇴적물 함량과 밀물우세 조류로 인하여 이 지역의 부유 퇴적물 이동은 저층을 통한 이동이 큰 중요성을 갖으며, 따라서 광양만의 내부 특히 서쪽 부분은 전체적으로 세립 퇴적물의 순수 퇴적이 이루어지고 있다. 이러한 조류에 의한 세립 퇴적물의 순수 유입량은 약 $5.66\times10^8g/day$로 계산되며, 이 순수 유입량이 만의 서부에 퇴적된다면 그 퇴적율은 약 1.15m/1,000years 정도가 될 것이다.

• 한국환경과학회지
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• 제25권1호
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• pp.1-10
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• 2016

Bottom sediment pollution with heavy metals of the Sventoji River in Ukmerge, Lithuania using X-ray fluorescence spectrometry is analyzed in this article. During the research, qualitative and quantitative parameters of heavy metal concentrations and their distribution were investigated. This article presents obtained results of study, where bottom sediment samples were examined from both shores of the river of Sventoji. During this research, received data was treated using GIS software, which helped to interpolate the data of concentrations into the research polygon of the river. GIS software also helped to evaluate the urban runoff influence to the bottom sediment quality and exclude sources of pollution. The runoff dischargers which transport surface wastewater to the river were registered before sampling. At the mouth of streams, flowing into the river of Sventoji, additional samples were taken. After comprehensive river bottom sediment research there is a possibility to assess the extent of anthropogenic activity and its impact on the river ecosystem and human health.

• Ocean Systems Engineering
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• 제13권3호
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• pp.313-324
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• 2023

The vertical distribution of suspended sediments in the mangrove-mud coast is complicated due to the characterization of cohesive sediment properties, and the influence of hydrodynamic factors. In this study, the time-evolution of suspended sediment concentration (SSC) in water depth is simulated by a one-dimensional model. The model applies in-situ data measured in October 2014 at the outer station in Cu Lao Dung coastal areas, Soc Trang, Vietnam. In the model, parameters which have influence on vertical distribution of SSC include the settling velocity Ws and the diffusion coefficient Kz. The settling velocity depends on the cohesive sediment properties, and the diffusion coefficient depends on the wave-current dynamics. The settling velocity is determined by the settling column experiment in the laboratory, which is a constant of 1.8 × 10^-4 ms^-1. Two hydrodynamic conditions are simulated including a strong current condition and a strong wave condition. Both simulations show that the SSC near the bottom is much higher than ones at the surface due to higher turbulence at the bottom. At the bottom layer, the SSC is strongly influenced by the current.

• 한국수산과학회지
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• 제31권3호
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• pp.330-342
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• 1998

영산강 하구역의 저서동물 군집구조 연구 일환으로 이 일대 해역의 저서환경을 조사하였다. 조사해역에 40개 정점을 설정하고 1995년 4월부터 1996년 2월까지 계절별로 표층 및 저층수괴의 수온, 염분 및 용존산소. 그리고 표층퇴적물의 입도분석과 함께 강열감량. COD 및 POC를 측정하였다. 수온은 표층의 경우 $4.1\~29.8^{\circ}C$, 저층의 경우 $4.0\~27.0^{\circ}C$범위였다. 염분의 경우 표층은 $15.1\~33.6\%_{\circ}$, 저층은 $21.5\~33.2\%_{\circ}$범위였다. 표층 수온은 여름철에는 내만역이 외측에 비해 높은 양상이었으며, 가을부터 봄까지는 내만역과 큰 차이를 나타내지 않았다. 저층수온은 여름철에 내만역에 형성된 성층으로 인해 외해역에 비해 상대적으로 낮은 양상이었다. 표층 및 저층염분은 담수가 간헐적으로 유입되는 내만역이 외해역에 비해 전 계절에 걸쳐 통해 낮은 값을 나타내었다. 용존산소는 표층의 경우 $5.1\~11.2mg/\ell$ 범위였으며 저층의 경우 $0.79\~10.2mg/\ell$였다. 특히 여름철에는 하구둑에서 목포항에 이르는 내만역의 광범위한 해역에 $2.0mg/\ell$ 이하의 저층빈 산소수괴가 형성되었다. 퇴적물의 평균입도는 $9.12{\pm}0.45\phi$로서 하구둑에서 외해역으로 나갈수록 입도가 조립해지는 양상이었다. 퇴적상은 내만역에는 실트성 점토질, 외측역에는 점토성 실트질의 퇴적상이었다. 퇴적물의 COD는 $6.15\~15.49mg\;O_2/g$범위로서 평균 $10.59{\pm}12.64mgO_2/g$였으며, 강열감량은 $3.35\~15.45\%$범위로서 평균 $6.96{\pm}1.91\%$였다. POC는 $0.61\~1.39\%$범위로서 평균 $1.07{\pm}0.16\%$였다. 이들 퇴적물 환경요소들의 공간분포양상은 내만역에서 높고 외해역으로 갈수록 감소하는 양상을 나타내었다. 저층수괴의 수온, 용존산소량, 퇴적물의 평균 입도, 점토 함량, COD 등 5가지 환경 요인을 사용하여 주성분분석을 실시한 결과 영산강 하구역은 저층수괴의 용존산소량과 퇴적물의 점토 함량에 따라 3개의 정점군으로 구분되었다. 영산강 하구둑에서 목포항 주변까지를 포함하는 내만역에 위치한 정점군은 표층염분과 저층수온이 낮으며, 입도는 상대적으로 세립하며 유기물 함량이 높고 여름철 빈산소 수괴가 형성되는 정점군이다. 고하도와 화원반도로 둘러싸이고 목포구 수로를 통해 외해역과 면해 있는 정점군에서의 퇴적물 입도는 상대적으로 조립하며 유기물 함량은 낮은 양상이었다. 또한 여름철에도 산소결핍 현상은 발생하지 않았으며, 저층수온과 저층염 분도 다른 정점군에 비해 상대적으로 높은 양상이었다. 한편 목포항 주변에서부터 외해역과의 중간에 위치한 정점군에서의 제환경 요소들은 두 정점군의 중간값을 나타내고 있다. 결국, 각 정점군의 점토 함량의 차이 및 세립한 입도와 높은 유기물 함량. 그리고 빈산소 수괴의 출현은 영산강 하구역에서 저서동물의 공간분포 양상에 영향을 미칠 수 있는 특징적인 환경요인이라고 판단된다.

• 한국물환경학회지
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• 제25권6호
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• pp.935-942
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• 2009

During period of the rainy season of spring tide Aug. 2005, the suspended sediment transport rate from Seomjin River increased ten times as high as neap tide of low river discharge. During ebb tide of high terrestrial input, the grain size of suspended particles of both surface and bottom layer of the water column, showed a uni-modal distribution with a dominant peak at coarse fraction, which suggests a characteristic development of floc-sized particles of low mean effective density. On the contrary, the particles supplied toward upstream of Seomjin river from Gwangyang Bay during flood tide showed a bi-modal distribution with a secondary peak at finer fraction, possibly due to the resuspension and the deflocculation associated with the increased shear velocity at near bottom. Break-up of large flocs is also suggested by the increased mean effective density. However, settling velocity was lower during flood tide because of smaller grain size. Thus, net deposition of suspended sediment is expected at within Gwangyang Bay instead of upstream of Seomjin River, even though suspended sediment transport rate at near bottom water was three times higher than that at surface water during flood tide.