• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.622-627
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• 2007

최근 하천의 모습은 이수 및 치수를 위해 설치된 수공구조물과 각종 오염원으로 인한 수질악화, 산업화 및 도시화에 따른 물순환시스템의 변화로 하천의 물순환 시스템이 바뀌게 되고 하천을 찾는 시민들의 환경의식 미성숙으로 인한 직간접적인 하천오염 활동이 이루어지고 있다. 하천에 대한 이러한 변화는 수질, 수량 및 하천의 구조적 측면에서 하천 생태계에 많은 영향을 끼치고 있다. 따라서 하천의 정상적인 기능을 회복시켜 하천 생태계 보전과 환경적으로 안정된 하천 조성이 이루어지도록 하기 위해서는 하천을 보다 자연스럽고 지속적으로 관리하기 위한 효율적인 환경유량의 관리가 필요하다. 하천의 전체적인 생태시스템을 고려한 환경유량의 관리를 위해서는 기존 환경유량의 개념, 산정방법 등 현황을 분석하고 하천 생태계에 영향을 미치는 인자들에 대한 관리방안을 마련하는 것이 중요하다. 본 연구의 목표는 하천생태계에 대한 영향인자의 장단점을 분석하고 이들이 어느 정도의 영향을 미치고 있는지를 정량적으로 파악함으로써 사회적으로 요구되는 환경유량을 산정할 때 어류 및 식생 등 하천의 생태계와 하천의 수량 및 수질, 하천의 수리구조물 등 하천의 구조적인 변화를 고려할 수 있는 방안을 마련하는 것이다. 이를 위하여 우선적으로 국외 선진국에서 활용되고 있는 다학제간 전문가 그룹(Multi-disciplinary Expert Team, MET)을 통해 하천 생태시스템을 분석하고 환경유량 산정 모형을 활용하여 저수지 댐과 연계 운영함으로써 어류 및 식생 등 생태서식처와 사회환경 개선에 필요한 유량을 유지할 수 있는 방안을 적용하고자 한다. 본 연구에서는 대상유역인 금강유역에 대해 환경유량을 산정하기 위한 개념모형을 구축하였다. 개념모형은 대청댐 건설 이전, 대청댐 건설이후${\sim}$용담댐 건설 이전, 대청댐과 용담댐 건설 이후 등 3개의 시나리오를 통해 하도 및 수변공간과 유량변화에 따른 유황분석 등을 통해 손실된 생태시스템을 정량화하여 궁극적으로는 복원을 위한 대응방안을 마련하도록 할 수 있도록 구축되었다. 또한 댐으로 인한 하류지역의 영향범위 및 하천생태계에 미친 영향을 감소하기 위하여 적절한 환경유량을 산정하기 위한 것이다. 구축된 개념모형을 바탕으로, 금강유역에 대한 기초적인 수문, 하천특성, 현장조사 등을 실시하였다. 향후에는 본 연구결과를 기초로 하여 환경유량을 산정하기 위한 모형을 개발하고 산정된 환경유량을 확보 및 관리하기 위한 방안과 친환경적인 댐 운영방안을 마련하게 될 것이다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.3
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• pp.198-205
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• 2010

The purpose of this study is to investigate the characteristics of the grain size distribution and organic matters to understand the current status of the tidal flat sediment for efficient management of Suncheon Bay. We investigated the characteristics of the surface sediments in the mouth area of the Suncheon Bay at fifteen stations in April and July, 2009. Specific conclusions were as follows. The sediments in the most part of tidal flat was shown as muddy facies(clay and silt contents was more than 90%), whereas in the tidal river affected by water flow from the Dongstream was shown as sandy facies. The analyzed values of the tidal flat sediment were in the range of $1.9{\sim}3.8{\phi}$(mean $2.5{\phi}$) for sorting, and -1.5~3.2(mean -0.3) for skewness, and 1.5~14.1(mean 3.9) for kurtosis. So we knew that the tidal flat sediments in the Suncheon Bay was mainly composed by fine-grained sediment. Erosion was happened in the tidal river, whereas sedimentation was occurred in the tidal flat. The most of organic matters was derived from the Dongstream. Total organic matters shown as ignition loss was 5.75%, COD and $H_2S$ values were lower than the eutrophication level(COD; 20.0 mg/g dry, $H_2S$; 0.2 mg S/g dry). From our research the tidal flat of the Suncheon Bay is relatively fine, but a part of the flat was exceed the environmental standard. So we have to establish effective countermeasures to reduce the organic matters and nutrients derived from stream for environmental preservation of the Suncheon bay and conduct scientifically sustainable monitering for streams flowing into Suncheon Bay and tidal flat.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.179-190
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• 2019

In this study, a fish survey was conducted to investigate the habitat status of black shinner (Pseudopungtungia nigra) designated as endangered species level from the lower part of Yongdam Dam to the upper part of Daecheong Dam. Biodiversity analysis was performed on the basis of the number of fish emerged, and biological health and physical habitat environment were quantitatively analyzed using collected P. nigra. According to the survey, the habitat range of P. nigra was found from Banguri-myeon, Buri-myeon, Geumsan-gun, downstream of Yongdam Dam. The biodiversity analysis results of all species appeared to be low in overall dominance index and relatively high in species diversity and uniformity index. In addition, P. nigra collected in this study was confirmed to have normal growth and nutritional status by the full-length-weighted relativities and condition factor. The physical habitat environment of P. nigra was 0.3 - 0.6 m in depth, 0.3 - 0.7 m/s in flow rate, and bed materials showed high frequency of occurrence in the range of cobbles (64.0 - 256.0 mm) to boulders (>256.0 mm). These results are expected to be used as data for habitat restoration and management in the future as basic data on the spatial range and preferred physical habitat environment of P. nigra in Geumgang.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.11-19
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• 2014

The objective of this research was to investigate concentration and load of nutrients such as total nitrogen (TN), nitrate nitrogen ($NO_3$-N) total phosphorous (TP), and phosphate phosphorous ($PO_4$-P) in a 23.4-ha paddy fields watershed with river water source. Water samples for irrigation water, drainage water, ponded water and groundwater were collected, and irrigation and drainage water were measured at 5~10 day intervals during normal days and at 2~6 hours intervals during three storm events. The amount of irrigation water in the study area was over 2,000 mm, which is almost identical to that in the area irrigated from a large reservoir but much more than that in the area irrigated from a pumping station. Mean flow-weighted concentrations of TN and TP in irrigation water were 2.8 and 0.15 mg/L, respectively, higher than those in the area irrigated from a large reservoir or a pumping station. The ratios of irrigation load to total inflow load for TN and TP were 88 %, and the ratios of surface outflow load to total outflow load for TN and TP were over 90 %, indicating that total nutrient load may be greatly affected by water management. The nutrient loads per area in the study area were estimated as TN 21.1 kg/ha and TP 1.1 kg/ha. Especially, the TP load per area in the study area was smaller than that in the area irrigated from a large reservoir or a pumping station. This may be because outflow load is not high likely due to sedimentation of particulate P and irrigation water load is high due to high TP concentration in irrigation water and high amount of irrigation water.

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.9-19
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• 2006

The accurate estimation of groundwater recharge is important for the proper management of groundwater systems. The widely used techniques of groundwater recharge estimation include water table fluctuation method, baseflow separation method, and annual water balance method. However, these methods can not represent the temporal-spatial variability of recharge resulting from climatic condition, land use, soil storage and hydrogeological heterogeneity because the methods are all based on the lumped concept and local scale problems. Therefore, the objective of this paper is to present an effective method for estimating groundwater recharge with spatial-temporal variability using the SWAT model which can represent the heterogeneity of the watershed. The SWAT model can simulate daily surface runoff, evapotranspiration, soil storage, recharge, and groundwater flow within the watershed. The model was applied to the Musimcheon watershed located in the upstream of Mihocheon watershed. Hydrological components were determined during the period from 2001 to 2004, and the validity of the results was tested by comparing the estimated runoff with the observed runoff at the outlet of the catchment. The results of temporal and spatial variations of groundwater recharge were presented here. This study suggests that variations in recharge can be significantly affected by subbasin slope as well as land use.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.591-602
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• 2018

Clithon retropictus has been designated as an endangered wildlife Class II due to its high value as a biological indicator species capable of judging environmental quality such as salinity, water flow, and ground conditions. However, basic research on its physiological and ecological characteristics is still lacking. As such, this study intended to examine the impact of environmental conditions such as salinity and soil particle size on the size and density of Clithon retropictus at the Yeoncho river estuary. The investigation of the salinity, which is a key variable that affects the distribution of organisms in the estuary, showed that Clithon retropictus could grow at a salinity ranging from 0#x2030; (freshwater) to 25‰ (brackish water). The coarse gravel (19-75mm) tended to increase nearer the upper stream (under the Yeoncho weir), while the proportion of particles smaller than sand (less than 19mm) increased toward the downstream. The population and the size of the individuals decreased rapidly in the downstream where water stagnated near the Yeoncho weir, and the salt water joined. The results indicated that Clithon retropictus had a high tolerance to salinity, but the adaptability was weaker toward the extremes since the population, and the size tended to decrease as the salinity increased. The correlation analysis revealed that both salinity and soil particle size affected the population and individual size. The correlation between the individual size and salinity was -0.242 (P <0.01), indicating that the size decreased with increasing salinity. The correlation between individual size and coarse gravel having a particle size of 19mm or more was 0.420 (P <0.01), indicating that the size increased with increasing the particle size.

• Ecology and Resilient Infrastructure
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• v.6 no.2
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• pp.89-100
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• 2019

We've reviewed existing studies on the interactions among vegetation, hydrology, and geomorphology in the stream corridors, adding one more factor of vegetation in the traditional area of hydro-geomorphology. Understanding of the interactions among those three factors is important not only academically but also practically since it is related intimately to the restoration of river corridor as well as management itself. Studies of this area started from field investigations in the latter part of the 20th century and focused on the flume experiments and then computer modelling in the 1990s and 2000s. Now, it has turned again to the field investigations of specific phenomena of the vegetative-hydrologic-geomorphologic interactions in detailed micro scales. Relevant studies in Korea, however, seem to be uncommon and far behind the international status quo in spite that practically important issues related directly to this topic have been emerged. In this study, we propose, based on the extensive literature review and authors' own knowledge and experiences, a conceptual diagram expressing the interactions among vegetation, flow (water), sediment, and geomorphology. Existing relevant studies in Korea since the 1990s are classified according to the categorization in the proposed diagrams and then briefly reviewed. Finally, considering the practical issues of riparian vegetation that have emerged recently in Korea, we propose areas of investigation needed in near future such as, among others, long-term and systematic field investigations and monitoring at multiple river corridors having different attributes on vegetative-hydrologic-geomorphologic interactions, including vegetative dynamics for succession.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.57-66
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• 2019

One of the most serious problems with concrete small dams or barriers installed in small/median rivers is the deposit of sediments, especially, in Korea. An effective way to discharge such sediments to downstream is to construct a bypass pipe under the river bed. However, efficiency may become lowered if ripraps are entered into the bypass pipe. Therefore, in this study, we derived the threshold condition for the exclusion of ripraps from the bypass pipe using 3D numerical analysis. Upstream flow of the small dam was assumed to be stationary, and the energy concept was applied to the control volume containing the bypass pipe and its periphery. As a result, when the ratio of the water level difference between upstream and downstream to the diameter of the riprap was approximately equal to 1.2, the threshold condition for exclusion of the stones or riprap from the bypass pipe was affirmatively determined. If the characteristics of the adsorptive sediment adversely affecting the river environment in the future would be taken into account, results from this study are expected to put to practical use in the management of concrete small dam with bypass pipe system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.27-36
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• 2006

Most of domestic multipurpose dams were basin area to be large, therefore, soil loss were occurred by downpour in the rainy season, They have caused to accumulate sediments on the river and dam reservoir that brought the decrease of storage volume and difficulties of the quality management of water. Until now, the measurement cycle of sediments surveying was long and it was designed to use surveying the degree of sediments, Thus there were many difficult things to secure accuracy. In this study, it was intended to analyze the origin position tracing of sediments and the movement route, for this purpose, aerial LiDAR technology was applied to precise sediments surveying. The amount and location of soil loss were evaluated by classified properties of soil, land-cover, and topographical conditions in detail. Therefore, the reliance could be maintained in analyzing the route of soil loss by extracting the flow within a watercourse and using the advanced accurate DEM.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.908-912
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• 2006

Geology and terrain of Imha basin has a very weak characteristics to soil erosion, so much soil particles flow into Imha reservoir and bring about high density turbid water when it rains a lot. Especially, since the agricultural area of Imha basin is mainly located in river boundary, Imha reservoir has suffered from turbid water by soil erosion. Therefore, it is important to estimate the influence of soil erosion to establish efficient management of water-pollutant buffering zone for the reduction of turbid water. By applying GIS-based RUSLE model, this study can acquire 12.23% that is the ratio of soil erosion in water-pollutant buffering zone and is higher than area-ratio (9.95%) of water-pollutant buffering zone. This is why the area-ratio of agricultural district (27.24%) in water-pollutant buffering zone is higher than the area-ratio of agricultural district (14.96%) in Imha basin. Also as the result of soil erosion in sub-basin, Daegok basin shows highest soil erosion in water-pollutant buffering zone, second is Banbyeon_10 basin and last is Seosi basin.