• Magazine of the Korean Society of Agricultural Engineers
• /
• v.42 no.5
• /
• pp.70-77
• /
• 2000

The fishways at Namdae-cheon and Osib-cheon were investigated from July 1998 through October 1999. There are three types of fishways on these rivers. those are baffied fishway, fish ladder, and fish ladder with gabion. Namdae-cheon has 7 baffled fishways and 19 fish ladders, and Osib-cheon has 7 gabion fishways. On namdae-cheon, 1,775 fishes of 24 species were collected. Among these fishes, 452 fishes of 11 species were anadromous fishes occupying 46% in species and 25% in number. On Osib-cheon, 1,953 fishes of 24 species were collected. Among these fishes, 483 fishes of 5 species were anadromous fishes occupying 21% in species and 25% in number. On Namdae-cheon the species number and abundance decreased gradually upstream. The poor structure of fishways seems to have worked as an obstacle to the upstream migration of fishes in the Namdae-cheon . On Osib-cheon all the observed fish species except three-spined stickleback(Gasterosteus aculeatus aculeatus) which stay and spawn around downstream of fiver could migrate upstream. The good structure of fishways on this river is thought to have helped upstream fish migration.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1999.10c
• /
• pp.721-726
• /
• 1999

The fishways on Namdae-cheon and Osib-cheon and the use of migratory fishes were investifated from July 1998 through Jung 1999. There are three types of fishways on these rivers. Those are baffled fishways, fish ladder, and fish ladder with gabion. Namdae-cheon has 7 baffled fishways and 19 fish ladder, and Osib-cheon has only fish ladder with gaboin. On Namdae-cheon 1,195 fishes of 24 species were collected. Amog these fishes 241 fishes of 9 species were anadromous fishes occupying 38% in species and 19% in number. On Osib-cheon 1,015 fishes of 24 species were collected. Among these fishes 240 fishes of 5 species were anadromous fishes occupying 21% in species and 24% in number. On Namdae-cheon the species number and auundance decreased gradually upstream. The poor structure of fishways seems to have worked as an obstacle to the upstream migration of fishes on Namdae-cheon. On Osib-cheon all the observed fish species except three -spined stickleback(Gasterosteus aculeatus aculeatus) which stay and spawn around downstream of river could migrate upstream. The good structure of fishways on this river is thought to have helped upstream fish migration.

• Parasites, Hosts and Diseases
• /
• v.25 no.1
• /
• pp.59-68
• /
• 1987

An epidemiological survey on Metagonimus yokogawai infection was performed in the eastern coast area of Kangwon province. Formalin-ether concentration technique and Stoll's dilution egg counting method were employed to figure out the prevalence and intensity of M. yokogawai infection and eating habits of inhabitants with raw freshwater fish. The results are summarized as follows: 1. The prevalence rate of M. yokogawai infection was 6.6% among a total of 2, 357 examinees; 8.6% (115 out of 1, 345) in male and 4.0% (40 out of 1, 012) in female. 2. The prevalence rates were different by the streams where the examinees were residing: 17.8% along the area of Ohsip-cheon (stream), 11.8% along Maeup-cheon, 1.7% along Hwasang-cheon, 1.3% along Yeongok-cheon, 0.9% along Namdae-cheon, 0.9% along Sa-cheon and 0% in the other streams (Yongchon-cheon, Kangnung Namdae-cheon and Jusoo.cheon) in decreasing order. 3. By social strata, the positive rate was 8.0% (122 out of 1, 521) in general inhabitants and 3.9% (33 out of 836) in school children. 4. By the intensity of infection by means of EPG counts in feces; the light infection (less than 400/EPG) was 74.1%, moderate infection (401-1, 000/EPG) 17.3% and heavy infection (more than 1, 001/EPG) 8.6%. 5. Twelves out of 50 sweetfish (Plecoglossus altivelis) (24%) caught from the streams in eastern coast of Kangwon-Do were infected with metacercariae of M. yokogawai, and the number of larvae detected were 70.7 per 6sh in average. The metacercarial infection rates in fish were also different by the streams; 100% in Ohsip-cheon of Samcheok-Gun, 14.3% in Sa-cheon, 16.7% in Yeongokcheon of Myeongju-Gun and 0% in Namdae-cheon of Yangyang-Gun, respectively. 6. Six hundred ninety live (695) out of 1, 396 inhabitants and school children (49.8%) were experienced in eating raw freshwater fishes (Plecoglossus altivezis, Triboledon hakonensis, Coreoperca sp., Morose sp., Carassius sp. & Cyprinus sp. and Zacco platypus). The data were assayed with the questionnaire collected from the examinees. In summarizing the above results, it is known that the Ohsip-cheon area of Samcheok-Gun is highly infected region, and the other areas of Kangnung Namdae-cheon, Yeongok-cheon and Yangyang Namdae-cheon are very lowly infected or non-infected regions for M yokogawai infection.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2004.05b
• /
• pp.671-675
• /
• 2004

The objective of this study is to develope estimation techniques of flood inundation area for given rainfall frequency using GIS. For this, Namdae-cheon is selected as pilot station and Inundation area is estimated with routing of flood volume from river mouth to upstream. As a results inundation area of Namdae-cheon estimated with $1.5km^2\~9.7km^2$ for $5\~500$ frequency years. In addition it is noted that results of this study can use in flood risk analysis for establishment of flood countermeasures.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.647-650
• /
• 2003

To provide the basic information for the water quality improvement of the Geumkang River Basin, the water qualities of the Namdae-cheon watershed were investigated from May in 1999 to September in 2003.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.7
• /
• pp.49-56
• /
• 2003

Nonpoint source pollutant loading from watershed may cause a problem to the water quality of the reservoir and stream. The characteristics of stream flow and water quality were monitored to investigate the runoff loading of the Namdae-cheon watershed from May in 1999 to October in 2003. Stage-discharge rating curve at the stream gauging site was established, and annual stream runoff of the study watershed was estimated as 499.4∼1,330.8mm during four years. The concentrations of total-nitrogen and total-phosphorus of stream water quality ranged from 0.76 to 6.95mg/L and from 0.0010 to 0.2276 mg/L, respectively, where T-N was generally higher than the water quality standard 1.0 mg/L for agricultural water use. The loads by unit generation of pollutant mass with respect to population, livestock, land use in this watershed were calculated. The runoff pollutant loadings by concentrations of total-N and total-P were estimated during study period, where the annual runoff loading of total-P was much less than the load by pollutant mass unit generation. The relations between stream discharge and water quality were analysed, and there was a high correlation for total-N but low for total-P. These results will be used to develop the monitoring techniques and water quality management system of agricultural watershed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.36 no.1
• /
• pp.25-32
• /
• 2018

Namdae-cheon in Gangwon-do Province, Korea, is a valuable well-preserved lagoon. The estuary of Namdae-cheon Stream is closed because of the surrounding natural sand shoal. Thus, during the dry season, river water cannot easily flow to the ocean and therefore stagnates. River water congestion causes environmental deterioration of estuaries, often by eutrophication. In this study, we examined wall disintegration in the estuary area and used it to determine appropriate measures for the conservation of estuary water quality in the future. A total of 24 sites were selected, with 13 sites on the west side and 11 sites on the east side of the estuary study area. Samples were collected and analyzed for particle size and moisture content both vertically and horizontally. Sedimentary deposition rate was measured, and subsidence analysis was performed. Particle size, water content, sedimentary deposition, and subsidence analyses indicated that flow shifted to the west during the study period. In conjunction with other variables that may affect changes in flow, these parameters can be used in future research to predict shoal breaches and associated changes in water flow direction.

• The Korean Journal of Quaternary Research
• /
• v.22 no.2
• /
• pp.19-22
• /
• 2008

• Korean Journal of Environmental Agriculture
• /
• v.19 no.1
• /
• pp.26-31
• /
• 2000

This study was carried out to investigate the changes of water quality, the pollutant loading by population, livestock, and land use at the Namdae-cheon in Keum river districts. Water samples were taken at the four sites of watershed, the nutrients of which were analyzed periodically from July, 1995 to April, 1998. Content of nutrients in water samples ranged from 1.8 to 5.8 mg/L for total nitrogen, from 0.01 to 0.08 mg/L for total phosphorus and from 0 to 0.007 mg/L for ortho-phosphate respectively. Nitrogen loading by pollutant unit was investigated 550.4 ton/yr as 358.1 ton/yr by livestock, 129.3 ton/yr by land use and 63.0 ton/yr by population. Phosphorus loading by pollutant unit was investigated 79.1 ton/yr as 60.6 ton/yr by livestock, 5.2 ton/yr by land use and 13.3 ton/yr by population. The loading of measured pollutant was investigated 452.5 ton/yr of nitrogen and 5.4 ton/yr of phosphorus in Namdae-cheon watershed.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2003.10a
• /
• pp.75-78
• /
• 2003

This study is to present a method of land cover change detection by the typhoon RUSA (August 1 - September 4, 2002) using Landsat 7 ETM+ images. For the Namdae-cheon watershed in Gangreung, two images of Sept. 29, 2000 and Nov. 22, 2002 were prepared. To identify the damaged areas, firstly, the NDVI (Normalized Difference Vegetation Index) of each image was computed, secondly, the NDVI values were reclassified as two categories that the negative index values including zero are the one and the positive index values are the other, thirdly the reclassified image before typhoon is subtracted from the reclassified image after typhoon to get DNDVI (Differential NDVI). From the DNDVI image, the flooded and damaged areas could be extracted.