• Journal of the Korean Society of Industry Convergence
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• v.10 no.4
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• pp.275-283
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• 2007

This study aims at the calculation of a variation of flow characteristics of main channel for tributary inflow in river junction. So this study was analyzed the variation of flow depth and velocity in main channel for a change of inflow degree. For this purpose, FLDWAV model are carried out for variations of $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$ tributary inflow at junction. Results show that velocity ratio(V1/V3) increases and flow depth ratio(H1/H3) decreases for discharge ratio(Q1/Q3) of upstream and downstream when degree increases in junction. And FLDWAV model was applied at a real river junctions. Selected area is a junction of Gumho river and Sin stream. Results show that pattern is similar to a virtual channel.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.1
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• pp.4614-4625
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• 1978

The construction of the equipment of water utilization has been developed since the ancient Korea period, 1906 in order to develope and modernize the agriculture. As the results, 83% of total paddy field area, 1,268,949.8 ha has developed into the irrigated paddy field, and the rest of area, 17% has remained nonirrigated paddy field (due to the data of the statistics of 1975). The ratio of the irrigated paddy field area among the total weir was marked 13.14% (area, 137,926.3 ha) and the third grade of total irrigated paddy field in accordance with the facilities of water utilization. In case of Gangwon-Do, the 44.18 percentage of the total irrigated paddy field, 51,057.2ha has been and pointed out first grade. As the results, we found out the following articles : 1. The total weir, 1,641 that sumed concrete weir 647 and conventional weir 967 has been constructed and has irrigated the 44.l8% of total irrigated paddy field of Gangwon-Do. 2. These weirs have been public possession of those villages to be 96.1 percentage of total weir and was controled by them. 3. Those weirs that were constructed across tributary (first, secondary and third tributary) at vallies (elevation 100∼1,000m) have marked that 45 percentage of total number of catchment area has 100∼1,000 ha, and 70 percentage of total number of basin area has been below 10 ha and has constructed about 5 of step-shape. 4. The construction of most weirs has became generally about 50m length, about 1m height. 5. The 80 percentage of newly constructed concrete weir has aged below 10 years. It seemed that 79 percentage of conventional weir has aged over 20 years and 41% of contructed weir has needed to be improved quickly. 6. If privious weirs, 296 will constructed newly, they can irrigate 3,600.8 ha of paddy field and 45.8% of total irrigated paddy field will have been and will contribute to the production of much rice.

• Journal of Wetlands Research
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• v.14 no.4
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• pp.715-723
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• 2012

The Hoelyongpo in the Naeseong River as tributary basin of the Nakdong River is broadly well-known a tourist attraction, which is made of sandy beach, and is called "Island of Inland". But Construction of the Dam was planned at upstream of river. In other words, an influx of sediment is blocked from upstream of river. In this situation, through sediment discharge coming from tributary of the Naeseong river, the whether to go ahead of sand beach of the Hoelyongpo is analyzed by using 1-D and 2-D model. The sediment discharge is estimated through ratio raw with basin area, and the instream flow requirement of river coming from dam and the flow rate and sediment coming from tributary are inputted for model. The 1-D model uses HEC-6 and the 2-D model uses SMS(RMA2 and SED2D). The analysis using the HEC-6 is performed from cross section data 10 year ago to the present cross section. Consequently, Yang equation presenting similar result to the present cross section data is determined, using this, the prediction is conducted for the cross section after 20 years. The 2-D analysis is conducted for the present cross section data. The value of distinction between a deposition and erosion with the results presented in the 1, 2-D models is occur, however, the appearance between the deposition and the erosion is similar.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.328-343
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• 2012

BACKGROUND: For effective subwatershed management, it is very important to select the tributaries for improving water quality and understand the characteristics of tributaries. Until now, however, the case study of main streams has been managed. 17 tributaries in Geum river subwatershed were monitored to regulate the source of water contaminations and identify their current situations in this study. METHODS AND RESULTS: As pollution indicators, such as biological oxygen demand($BOD_5$), chemical oxygen demand($COD_{Mn}$), suspended solid(SS), total nitrogen (T-N), total phosphate(T-P) and total organic carbon(TOC) in Geum river were examined from January to December in 2011. The results were as follows : The annual average concentration of nutrients in Yongdam reservoir upsteam was 0.7 mg/L for BOD, 3.0 mg/L for COD, 8.4 mg/L for SS, 2.905 mg/L for T-N, 0.035 mg/L for T-P and 1.6 mg/L for TOC. Water quality of Daechung reservoir upstream was mostly similar tendency in comparison to Yongdam reservoir upstream. Among the 22 tributaries, water quality in Daechung reservoir downstream was more polluted. T-N contents were significantly high in Miho B4 located Daechung reservoir downstream(annual average concentration: 13.53 mg/L). In cases of Miho A1, A2 and C1, pollution degree was worsened during rainy season expecially. CONCLUSION(S): For improving water quality of Geum river subwatershed, the tributaries in the Mihocheon area should be preferentially considered. Mihocheon tributary is the highest in pollution site, and thus a study on long-term effects should be research.

• Korean Journal of Environment and Ecology
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• v.24 no.5
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• pp.556-565
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• 2010

Community analysis based on functional feeding groups of benthic macro invertebrates at Wangpi-cheon was assessed with the result of four field survey from October, 2007 to May, 2008. A total 138 species of benthic macro invertebrates in 58 families, 16 orders, 6 classes, and 4 phyla were collected during the field surveys. The result of EPT index value showed high value of 61.59% and it means that the stream ecosystem of Wangpi-cheon is very clear and healthy. In this study the functional feeding groups in Wangpi-cheon were divided into two groups. First, Scrapers and Collectors-Gathering group which is normally dominant in midstream showed higher dominance in main stream than tributary. Second, shredders group showed higher dominance in tributary than main stream like as the general characteristics of upriver. With the result of cluster analysis based on the similarity index, the study areas could be grouped into a natural area(A group) and an artificial disturbance area(B group; site 8 and 11) where embankment, bank and levee had been built near by. And also, the natural area(A group) was classified into two groups which had the characteristic of main(site 1, 2, 3, 4 and 7) stream and tributary(site 5, 6, 9 and 10) respectively.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.638-646
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• 2018

The purpose of this study was to investigate the long-term habitat morphological alteration resulting from a large dam and weirs in the Tamjin River. To achieve this, we carried out a hydrograph analysis and a substrate size distribution analysis. We also estimated the channel width, bar area and vegetation encroachment using aerial photographs taken before and after the construction of the dam and weirs. The result of the hydrological analysis showed that flooding downstream was greatly reduced with small peaks occurrence after the dam construction. Interestingly, normal hydrographs in the main channel appeared just after tributary conjunction. There was a similar pattern in the substrate size analysis. Despite coarsened substrate just downstream of the dam site, more sand appeared again after introduction of the tributary. However, there was an increase in the bar area downstream of the dam's channels with most bars covered with vegetation. The channel width increased at the upper area of weirs through impoundment, but decreased downstream because of vegetation encroachment. This study indicate that unregulated tributary plays an important role in restoring hydro-physical habitat conditions in mainstream channels below a large dam. However, numerous weirs could be a causal factor to accelerate habitat deterioration in the dam downstream channels.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.300-305
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• 2005

To trace the flood inundation area around rural small stream, RADARSAT image was applied because it has the ability of acquiring data during storm period irrespective of rain and cloud. For the storm of 9 August, 1998 in Anseong-cheon watershed, three temporal RADARSAT images before, just after and after the storm were used. After ortho-rectification using 5 m DEM, two methods of RGB composition and ratio were tried and found the inundated area in the tributary stream, Seonghwan-cheon and Hakseong-cheon. The inundated area had occurred at the joint area of two streams, thus the floodwater overflowed bounding discharge capacity of the stream. The progression of damage areas were stopped by the local road and farm road along the paddy.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.739-747
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• 2011

The major 81 tributaries in Chungcheongnam-do were monitored for flowrate and water quality in order to understand the characteristics of the watershed and to select the tributary catchment for improving water quality. The value of flowrate in the tributaries at Nonsancheon catchment at the Geum-River watershed and Gokgyocheon, Muhancheon, Sapgyocheon at the Sapgyo-Reservoir watershed, which is located in the southern and northern area in Chungcheongnam-do, was relatively greater than the other watersheds. The concentration of water pollutants regardless of water quality parameters in Nonsancheon catchment at the Geum-River watershed, Gokgyocheon catchment at the Sapgyo-Reservoir watershed and the Anseongcheon watershed, which have a dense source of pollution, were higher than the other watersheds. However, 64 percent of the tributaries at the Geum-River watershed, 45 percent of tributaries at the Sapgyo-Reservoir watershed, 26 percent of tributaries at the Geum-River watershed all satisfied the Class II regulations in the Framework Act on Environment Policy, but all of the tributaries located in the Anseongcheon watershed exceeded the Class II regulations. Therefore, the policy for improving the water quality of the tributary in Chungcheongnam-do should be established in the following order: Anseongcheon, Seohae, Sapgyo-Reservoir watersheds. Consequently, the tributary catchment for improving water quality, which has a large flowrate and a high concentration of water pollutants, was selected at Ganggyeongcheon, Geumcheon, Nonsancheon, Seokseongcheon, Seungcheoncheon, Jeongancheon, Jeungsancheon (so far Geum-River watershed), Gokgyocheon, Namwoncheon, Maegokcheon, Muhancheon, Sapgyocheon Oncheoncheon, Cheonancheon (so far Sapgyo-Reservoir watershed), Gwangcheoncheon, Dangjincheon, Daecheoncheon, Dodangcheon, Waryongcheon, Cheongjicheon, Pangyocheon, Heungincheon (so far Seohae watershed), Dunpocheon, Seonghwancheon, Ipjangcheon (so far Anseongcheon watershed). The plans as installation of environmental facilities to reduce the source of pollution for improving the water quality of these tributary catchments should be urgently established and implemented.

• Journal of Korean Association for Spatial Structures
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• v.9 no.4
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• pp.81-88
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• 2009

Damage on low?rise buildings caused by typhoons and storms is increasing every year. Thus, this study examined the distribution of wind pressure coefficient at each position according to the height of monosloped roof, and measured wind pressure coefficient according to tributary area and compared it with the current wind load standard. We analyzed six areas in order to analyze characteristics at each position of a half span roof, and found that the wind pressure coefficient was around 25% higher at the high comer (HC) than at the low corner (LC). The distribution pattern of peak pressure coefficient at each position was the same as the AIK load standard, but in the results of our experiment, wind pressure was around 40% lower than the load standard at HC and around 37% higher than the load standard at LC.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2244-2248
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• 2008

This study was focused on estimated Stream Maintenance Flow and performed for simulate securing Stream Maintenance Flow in New town development area. Tributary streams were made of 6 small streams, joined Gong-ji Stream and Eu-am lake finally. For estimate Stream Maintenance Flow used Kajiyama and SWAT models for calculate available flow in study area. As a result the annual average stream flow dry years were $2,300{\sim}136,000\;m^/day3$, the annual average stream flow wet years were $4,800{\sim}136,031\;m^3/day$. The coefficient of determination($R^2$) and Nash-sutcliffe coefficient(EI) for comparison between Kajiyama and SWAT models were 0.88, 0.78 respectively.