• 수산해양기술연구
• /
• 제30권3호
• /
• pp.142-149
• /
• 1994

In order to investigate the environmental properties of set net grounds located in the coastal waters of Yeosu. The current in the vicinity of set net grounds was observed by drogue and current meter in 1990 and 1992. The results obtained are summarized as follows: The direction of tidal current at the north enterance of Yeosu bay was southerly in ebb and northwesterly in flood without the distiction of the neap tide and the spring tide. In spring tide the maximum Velocity of the tidal current was 68 cm/sec in ebb and 66 cm/sec in flood. In neap tide the maximum velocity of the tidal current was 37 cm/sec in ebb and 35 cm/sec in flood. And so the direction of residual current was the south ward mainly and 21 cm/sec. The direction of tidal current at set net fishing grounds was southwesterly in ebb and westerly or northwesterly in flood. Regardless of the distinction of neap and spring. The maximum velocity of the current in spring tide was 50 cm/sec in ebb and 40 cm/sec in flood and that in neap was 28 cm/sec in ebb and 25 cm/sec in flood. In spring tide the speed vector along the major axis of semidiurnal tide component was three times as large as diurnal tide. In neap tide, however, the speed vector was about 50% less then that in spring tide, and the semidiurnal tide and diurnal tide were equal in the size of current ellipse and the direction of major axis. The sea area had a southwesterly residual current. 11 cm/sec in spring tide and 7 cm/sec in neap tide. According to the result of drogue tracking, the vicinity of set net fishing ground had a southerly residual current which formed in Yeosu Bay and a weak westerly residual current toward Dolsando from Namhedo. Therefore, set net fishing ground in coastal water of Yeosu was distributed in boundary of inner water which formed from Seamjin river and offshore water supplied from the vicinity of Sorido and Yochido.

• Fisheries and Aquatic Sciences
• /
• 제23권4호
• /
• pp.14.1-14.14
• /
• 2020

We performed field measurements of the behavioral changes in cultured chub mackerel (Scomber japonicus) caused by tide-induced changes in the shapes of their small-sized tetragonal fish cages. The field measurements were conducted in two separate periods: neap tide, a period in which the shape of the fish cages was stable; and spring tide, a period in which the fish cages are significantly deformed, which was expected to have significant influences on fish behavior. In the spring tide, the cages were deformed greatly by the moving water, with different water velocities affecting the cages to different degrees; the volume loss was estimated at 4.9% and 7.3% for v = 0.114 m/s and v = 0.221 m/s, respectively. The fish exhibited significantly different behaviors between the neap tide and spring tide. During the neap tide, the fish remained in the lower part of the cage, but during the spring tide they made frequent upward and downward movements, and their horizontal distribution changed significantly due to the changes in the shape of the cage. The cage deformation during the spring tide greatly influenced the swimming behavior of fish.

• 수산해양기술연구
• /
• 제47권4호
• /
• pp.338-343
• /
• 2011

To obtain the effective sampling estuarine fauna by a passive net in the West Sea of Korea occurring strong tide, catch were collected by bag nets with various sampling trials off Ganghwa Island in November 2009. We compared the difference of community structures (on spring tide vs. neap tide, total sample vs. subsample and 4 nets vs. 1 net) with each species composition as a sampling unit by the Pearson chi-square test. Number of individual at the spring tide was more abundant than that at the neap tide (p<0.0001) although number of species at the spring tide was not significantly different with that at the neap tide (p=0.174). Both number of species (p=0.138) and number of individual (p=0.096) were not significantly different between total sample and random subsample. Number of species was not significantly different between the subsample by 1 net and the subsample by 4 nets (p=0.515), but number of individual was a little different on both samples (p=0.024). In conclusion, we suggest the subsample by 1 net at spring tide as the effective sampling estuarine fauna by a passive net in the West Sea occurring strong tide.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2000년도 학술발표회 발표논문집
• /
• pp.371-377
• /
• 2000

Environmental impact on a land reclamation project, Hwaong tidal barrier was studied using the dispersion and advection model to predict the influence of polluted water discharged from freshwater reservior. The simulation results show that the distribution of concentration by influence of polluted water discharged during a tidal cycle appeared to be extinguished at atmost all points after two tidal cycle. Peak concentration near the sluice gate is found out to be higher during the spring tide than neap tide. Equi-concentration contour line appeared to distributed a longer according to line of sea dike in spring tide than neap tide. The reasons is because influence by currents of northwest direction is a stronger, compared to spring tide and neap tide in the flood tide.

• 한국해양학회지
• /
• 제13권1호
• /
• pp.29-34
• /
• 1978

인천항 부근해역은 우리나라 연안에서 가장 조차가 큰 천해역으로서 연안 및 섬주위로 간석지가 매우 잘 발달되어 있다. 따라서 동 해역은 오래전부터 큰 조차를 이용한 조력발전 후보지로 인정되어 왔고 앞으로의 개발전망이 밝을 뿐 아니라 광대한 간석지를 개발하기 위한 간척사업 후보지로 각광을 받고 있다. 이와 같은 개발계획의 대상으로 인정되는 해역에 있어서의 조류에 대한 정확한 조사연구는 중요한 일이라 생각된다. 인천항 부근해역의 조류에 관해서는 이(1963), 강(1972) 및 이(1972)등의 조사보고가 있는데 이들 조사관측 및 국내에서 실시되어 온 일반적인 조류관측은 거의 대부분이 동시관측에 의한 것이 아닐뿐더러 각 조기별 즉, 대조, 중조, 소조,기별로 실시된 것이 아니므로 각 조기별로 또한 각 지역별로 동시에 나타나는 조류의 특성을 비교하는 데에는 문제점이 있었다 하겠다. 우리나라 남해안이나 특히 서해안과 같이 조석이 큰 해역에서는 각 조기별로 조류의 특성이 매우 다르기 때문에 이를 비교파악 하기 위한 여러 지점에서의 조기별 동시 조류관측은 매우 어렵지만 의미있는 일이라 생각된다. 본조사에 있어서는 특히 이러한 점을 최대한으로 고려하여 실시되었다.

• 한국물환경학회지
• /
• 제27권4호
• /
• pp.542-550
• /
• 2011

Changes of suspended sediment concentration in the Seomjin river estuary located in south sea of the Korea peninsula were investigated during the spring tide in autumn (i.e. 25 hours in October) 2000 and winter (i.e. 25 hours in February) 2001. The changes of temperature and salinity during the spring tide in October 2000 showed larger variations than the those in February 2001. During the spring tide in October 2000, currents at bottom layer were observed to be stronger than during the spring tide in February 2001, showing that both of the two periods had ebb currents-predominant tide asymmetries. The suspended sediment concentrations in October 2000 were larger than the those in February 2001. At the time of the maximum of tide currents or after about one hour of the maximum during the autumn months, the suspended sediment turbidity was observed to be maximum. Another observation station at Hadong upstream from the Seomjin river estuary showed about one hour delay in tide phase, Thereby, the suspended sediment concentration showed high turbidity after two hours at bottom and three hours at surface layer, in particular, in October 2000. This results can be explained by the facts that river discharge increased significantly after the summer rainy season, causing also increase of erosion processes by strong current velocity at bottom layer.

• 한국수산과학회지
• /
• 제26권4호
• /
• pp.346-352
• /
• 1993

Tidal currents and tidal residual currents in Chinhae Bay are investigated by the field observations and hydraulic experiments during the spring tide and neap tide. The horizontal and vertical scales of the model are l/2,000 and 1/159, respectively. The hydraulic model results roughly coincide with the field data. Maximum tidal currents during the spring tide and neap tide in the central channel of Chinhae Bay are strong as about 90 and 30cm/s respectively, and strong tidal residual currents take place. Maximum tidal currents during the spring tide and neap tide in the western and northern part of the bay are weak as below 30 and 10cm/s respectively, and also tidal residual currents are weak. Tidal residual currents rotating clockwise occur in the central part of the bay. Northward tidal residual currents in the northern part of Kajo-do are predominant, whereas southward ones in the southern part of Kajo-do are remarkable. The surface currents in the bay depend strongly on the wind and river flow, and it seems to be remarkable during the neap tide.

• 한국해양학회지
• /
• 제7권2호
• /
• pp.86-97
• /
• 1972

The tides, tidal currents and tidal prisms at Inchon Harbor are studied with recent data. The tides at Inchon Harbor is of semi-diurnal type having a spring range of 798cm and a phase age of 2 days. The monthly mean sea level at Inchon has a maximum at August and a minimum at January with a annual range of about 40cm. the tidal currents at Inchon Outer Harbor are of semi-diurnal type same as tides and nearly reversing type. The flood and ebb currents set north and south with a velocity of about 90-175 cm/sec and 120-225 cm/sec at spring tide and begin 0.2 hours after L.W. and 0.7 hours after H. W., respectively. Non-tidal currents flow southward with 10-20 cm/sec at west side of the stream and northward with 15-20 cm/sec at east side of the stream at Inchon Outer Harbor. The flood volume through the Inchon Outer Harbor fluctuates fortnightly from 590 10$\^$6/㎥ spring tide to 260 $10^6/m^3$ at neap tide and ebb volume changes from 470 $10^6/m^3$ at spring tide to 200 $10^6/m^3$ at neap tide, respectively. The flow area along the channel to the Estuary of Yeomha is controlled by the tidal prism as expressed by $A=1.14{\times}10^{-4}P^{0.966}$

• 한국해양학회지
• /
• 제16권1호
• /
• pp.31-37
• /
• 1981

우리나라 남동부의 광범한 유역을 따라 흐르는 낙동강은 국내에서 가장 긴 하천의 하나로서 영남지역을 굽이쳐 흐르다가 부산 앞바다를 통하여 대한해협에 유입한다. 이 강의 하구는 유역주민의 생활 및 산업용수원으로서 중요할 뿐만 아니라 최근에는 산업입지 및 자연환경 보전문제로서 논의의 대상이 되고 있다. 낙동강은 하구로부터 약 40km상류까지 상향류를 보이며, 약 60km상류까지 조석의 영향을 받는 감조하천으로서 (유 장 1979), 하구역에는 해수, 하천의 담수 및 양자의 혼합수가 조석의 간만등 여러 가지 요인에 따라 유출되기도 하고 유입되기도 한다.

• 한국환경과학회지
• /
• 제5권4호
• /
• pp.473-479
• /
• 1996

The temnoral variations of the suspended material concentration (SMC) during spring-neap tidal cycle was investigated at more than 30 stations in Deukryang Bay, Korea, in 1 and 23 July, 1992. The averaged total SMC in spring tide was two times more than those in neap tide. It can be explained that the strong tidal current in spring tide disturbed bottom waters and induced higher SMC in the bay. The areal distributions of SMC for the surface and the bottom layers in the bay shows much different patterns during spring and neap tidal cycle. We concluded that the vertical stratification intensity of water mass is important factor of the horizonatal distribution of SMC in the bay.