• Journal of Fisheries and Marine Sciences Education
• /
• v.17 no.2
• /
• pp.155-169
• /
• 2005

The Pressure-State-Response (PSR) framework was used to develop sustainability indicators for the Han River estuarine area. A total of 37 indicators in three categories were derived after reviewing previous studies. Some of these indicators were selected to assess the sustainability of the Han River estuary and its watershed. Some indicators provided contrasting information for judging the sustainability of the area. Even though very limited information was available for the meaningful assessment of the sustainability of the Han River estuarine area, there seems to be an appropriate base for the sustainable development of the area. Securing of reliable information seems to be the key for the indicators to produce meaningful assessment of the implementation of the sustainable development strategy for the Han River Estuary and its watershed. Integrated indices to synthesize the information provided by the sectoral indicators need to be developed to overcome the limitations of the sectoral indicators.

• Korean Journal of Microbiology
• /
• v.6 no.4
• /
• pp.107-112
• /
• 1968

Examining the microbial populations in the Han River estuary, we conducted this experiment at six sites of the estuarine area, Chollyu-ri, Cholsan-ri, Wolgon-ri, Chogi-ri, Inhwa-ri, and Oepo-ri for 5 months since May 1967. From the results obtained it could be summarized as follows. 1) The salinity of the estuarine water increased in order of the distances from the base point of the Old Han River Bridge to every site of the estuary, and pH of the water, which were between 7. 3 and 8. 1, showing little difference each other in both the sites and dates of experiment. 2) The populations of the general bacteria and coliform group bacteria were highest at the site of Chollyu-ri, and it decreased with the downstreaming of the river water toward Oepo-ri site. As for fungi which have comparatively high tolerance to the salinity, its population was shown hi hest at Chogi-ri. 3) The relationship between the salinity and the number of the general bacteria have indicated that the incresed salinity reduced the growth rates of the bacteria. By this it can be assumed that the fresh-water bacteria decreased due to the sea water as well as its dilution effects. 4) The high pollution of the esturarine water was caused by the increases of inhabitants and water thrown by industries in Seoul and Kyung-In Industrial District as well as the excrements fertilized to the farms.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.6
• /
• pp.819-829
• /
• 2018

The bed change survey was carried out and its tendency was analyzed at the downstream of the Singok Submerged Weir in the Han River Estuary (HRE). In order to focus on the bed change in the low flow channel, we calculated the mean bed elevation based on the bankfull discharge. Thanks to the amount of bed changes calculated by using the 'averaged bed', we could compare the riverbeds of various periods with consistent criteria. In the HRE, revealed was the bed change cycle between degradation by flood and aggradation by tide at the non-flood season.

• Journal of Wetlands Research
• /
• v.24 no.4
• /
• pp.320-330
• /
• 2022

The Hangang river estuary, which is a natural estuary without structures such as estuary barrage, is an ecological pathway connecting the sea and rivers. Accordingly, Hangang river estuary has various species, and there is very valuable. Sediment classification in Hangang river estuary is three-dimensionally and diversely is distributed. Sediment classification in Hangang river estuary is also sensitively changed according to various factors such as climate change and river development. It is typically cause to landform and to develop a compound cross section. In Janghang wetland, the plant success is remarkable according to the morphological change at river bed. The purpose of this study is to identify the mechanism of wetland formation based on the observation on-site. As a result of the observation, Janghang wetland where was artificially created, has been grown according to the river bed change based on the flow rate and the plant success. The viscous surface layer material(fine grains of wash rod properties), which is not the main material(sand) of the river bed, but sub-materials of river bed, jas been settled on the pioneer plants(bolboschoenus planiculmis, etc.). It is an important role in the growth of a compound cross section and a wetland. After the wetland developed to the compound cross section, it is observed that the pioneer plants are transferred to other plant species.

• Korean Journal of Ichthyology
• /
• v.28 no.3
• /
• pp.192-199
• /
• 2016

The Seokmo and Yeomha channels are representative areas of high tidal energy in the Han River estuary. Surveys of environmental variables and abundance of Coilia spp. larvae, an anadromous fish, were carried out following the tidal cycle in August 2007 and August 2008. It was found that mean water temperature varied by <$1^{\circ}C$ across flood and ebb tides. A clear difference in salinity was observed between tides, with a high of 15.1 psu during flood tide, and a low of 0.8 psu during ebb tide. Coilia spp. larvae were significantly more abundant during the ebb tide than the flood tide (p<0.05). Since Coilia spp. larvae are anadromous fish, it seems that they use the ebb tide as a Selective tidal stream transport (STST) for horizontal movement in order to settle in the estuary (cultivation area), following hatching in the upper/middle courses of the Han River. A high percentage of larvae with improved swimming ability (measuring ${\geq}13.6mm$ in length) was observed during the ebb tide.

• Korean Journal of Ichthyology
• /
• v.26 no.4
• /
• pp.303-309
• /
• 2014

Feeding ecology of Collichthys lucidus was determined by analysis of stomach contents of 926 specimens ranged from 3.5 to 18.5 cm in the Han River estuary. This fish actively fed on benthic crustaceans, mainly decapods, Palaemon carinicauda and Acetes chinensis, and they can be defined as the benthivorous predator. The percentage of empty stomachs was 23.8%. The vacuity index (VI) did not vary with the size classes, but showed significant monthly variations. Monthly variation of feeding activity appears to be related to the reproduction cycle of the fish, and to the temporal abundance of the prey organisms. Collichthys lucidus in Han River estuary fed on a wide array of prey items and could be considered as a non-selective predator.

• Korean Journal of Ichthyology
• /
• v.26 no.2
• /
• pp.125-132
• /
• 2014

Seasonal variation and abundance of fish larvae in Han River estuary were determined by analysis of seasonal samples collected from three channels in the Han River estuary from May 2007 to August 2008. During the study, a total of 3,642 fish larvae were collected belonging to 13 taxa. Coilia spp. was the most abundant (48.8%). The highest number of taxa (11 taxa) was collected in the Jangbong channel and abundance was high in the Sukmo channel (2,428 ind./$1,000m^3$). Brackish-water species were prevailed in the Yumhwa channel and the Sukmo channel, while coastal species were abundant in the Jangbong channel. Canonical correspondence analysis revealed that the environmental factors such as water temperature and salinity had a strong relationship with the abundance of major larvae species.

• Journal of the korean society of oceanography
• /
• v.32 no.4
• /
• pp.202-207
• /
• 1997

Species composition and abundance of fish larvae were studied from May 1988 through August 1989 in the Han River Estuary and adjacent Kyunggi Bay, Korea. Of 23 taxa identified, Coilia nasus, llisha elongata, and Cyprinidae spp. were dominated. Maximum density (3,5771/1,000m)$^3$ occurred in August 1988 and minimum (3/1,m$^3$) in February 1989. O1igo- ormesohaline species dominated during ebb tides while polyhaline species during flood tides. Correspondence analysis revealed that three distinctive species groups; oligohaline species, Coilia nasus, Ilisha elongata and Cyprinidae spp., which dominated at both channels of Kwanghwa Island (stations 1, 2), mesohaline species, Sardinella zunasi and Gobiidae spp., at the mouth of Yeomha Channel (station 3), and polyhaline species, Engraulis japonicus and Syngnathus schlegeli, in the middle of Kyunggi Bay (station 4). Coilia nasus was the most abundant species and reported first time in the study area. Given the species composition and density of fish larvae, the Han River Estuary is considered to be a major spawning and nursery ground for brackish water species such as Coilia nasus, Ilisha elongata and some Cyprinidae spp.

• Journal of the korean society of oceanography
• /
• v.38 no.2
• /
• pp.80-86
• /
• 2003

The horizontal distributions of $^{224}Ra$ (half life=3.4 days) and $^{223}Ra$ (half life=11.3 days) were measured in surface seawaters of the Nakdong River estuary and the South Sea of Korea in April and October 2002. In order to determine these short-lived Ra isotopes, we used a delayed coincidence counter which is much more rapid and accurate than traditional methods. In an estuarine mixing zone (salinity, ~l6 ppt), the activities of $^{224}Ra\;and\;^{223}Ra$ were much greater than what would be expected from a mixture of freshwater and seawater in the Nakdong River estuary. This excess Ra may be a result of Ra desorption from fresh sediments originating from the river upstream. However, in the more open areas of the Nakdong River estuary (salinity>30 ppt) and the South Sea of Korea, $^{224}Ra\;and\;^{^{223}Ra$ activities decreased exponentially as a function of distance offshore. Using the decrease of $^{223}Ra$ with distance offshore in the South Sea of Korea, we estimated the apparent horizontal eddy diffusivities. The apparent eddy diffusion coefficients in South Sea of Korea are calculated to be approximately $3500-8000\;\textrm{m}^2/sec$.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.9 no.4
• /
• pp.196-203
• /
• 2004

To understand the geochemical processes in the Han River Estuary, distributions and behaviors of nutrients, dissolved organic matters, and uranium were investigated and analyzed during estuarine tidal mixing in June 2000 and February 2001. The distribution of inorganic nutrients showed very dynamic distributional patterns implying an apparent nitrification process and a concave non-conservative mixing along the salinity gradient. Dissolved organic carbon was high in the upstream region and decreased sharply in the low salinity region of around 5 psu. The 3-D fluorescence characteristic of dissolved organic matter showed two distinct fluorophores in the study area. Biomacromolecules originated mainly from the indigenous biochemical processes and geomacromolecules from terrestrial humic materials. In the study area, the distribution of geomacromolecule showed a concave non-conservative property along the salinity gradient presumably due to the flocculation and removal processes in the estuary. Meanwhile, distribution of the dissolved uranium, mainly in the form of stable uranium carbonate complex, also showed a concave non-conservative property along the salinity gradient in the Han River Estuary. From this study, the removal rate of dissolved uranium in the Han River Estuary was estimated to be about 7.1 ton per year.