• Journal of Environmental Science International
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• v.24 no.8
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• pp.1085-1099
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• 2015

The purposes of this study were to suggest the methodology to select prior areas in the environmental pollution survey for livestock excreta (EPSLE) as well as to elucidate the validity of the methodology. In this study, the prior areas in the EPSLE were determined by examining the number of compost facilities categorized according to the three levels of size including the basin, the sub-basin and the watershed, respectively, based on the data from "Annual Nation-wide Pollution Sources Survey (2012)". The results suggested that the list of prior basins were Nakdong, Geum, Youngsan and Han river basins in order. Also, it was examined that the prior sub-basins in the four river basins including Nakdong, Geum, Youngsan and Han rivers were Naesung Stream, Geumgang Gongju, Juam Dam and Namhan Downstream, respectively. The prior watersheds in the sub-basins of Naesung stream, Geumgang Gongju, Juam Dam and Namhan Downstream were Seocheon Downstream, Geum Stream, Gyeombaek Suwipyo and Yanghwa Stream, respectively. The validity of the methodology used in this study was elucidated by analyzing the correlation of the number of compost facilities with the concentrations of T-N and T-P observed in the end-points of sub-basins. The results of correlation analysis showed that the concentrations of T-N and T-P increased with the number of compost facilities. Specifically, there was the stronger correlation between the number of compost facilities and the concentrations of T-N than that for T-P. Consequently, it was proved that the methodology used in this work was valid and rational for the selection of prior areas in environmental pollution survey for EPSLE.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.100-107
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• 2002

This study investigates the seasonal variation and spatial distribution characteristics of pollutant load, as executing the quantity valuation of pollutant load inflowing into Yeong-Il bay from on-land including the Hyeong-san river. Annual total pollutant generating rate from Yeong-Il bay region are 202ton to BOD, 620ton to SS, 42ton to T-N, 16ton to T-P respectively, if expressly point out, pollutant generating rate from the Hyeong-san river is the greatest, which BOD ratio is 78.2%, SS 88.5%, T-N 62.5%, T-P 73.1%. As calculating Tank model with input value of daily precipitation and evaporation of 2001 year in drainage basin of the Hyeong-san river, Estimated result of the annual total river discharge effluencing from this river is $830{\times}106m^3$. As result to estimating annual total effluence rate outflowing at the rivers from each drainage basins, annual total inflow pollutant rate are BOD 10,633ton, SS 19,302ton, T-N 15,369ton, T-P 305ton. The III basin which is population congestion region of the Pohang-city drain away a good many pollutant load than the V basin including the Neang-Chun with wide drainage area. Especially, a great many T-N than T-P inflow into Yeong-Il bay. The accumulation of pollutant load effluenced from on-land will happen on at the inner coast region of Yeong-Il bay, finally we would make a prediction that the water quality will take a bad turn.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.142-142
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• 2023

Humans inevitably and continuously produce wastewater in daily life worldwide. To decrease the degradation of river water bodies and aquatic ecosystem therein, humans have built systems at different scales to collect, drain, and treat household-produced wastewater. Particularly, municipal wastewater treatment plants (WWTPs) with centralized controls have played a key role in reducing loads of nutrients in domestic wastewater for the last few decades. Notwithstanding such contributions, impaired rivers regarding water quality and habitat integrity still exist at the whole river basin scale. It is highly attributable to the absence of dilution capacity of receiving streams and/or the accumulation of the pollutant loads along flow paths. To improve the perspective for individual WWTPs assessment, the first crucial step is to achieve systematic understanding on spatial distribution characteristics of all WWTPs together in a given river basin. By taking the initiative, our former study showed spatial hierarchical distributions of WWTPs in three large urbanized river basins in Germany. In this study, we uncover how municipal WWTPs in the contiguous United States are distributed along river networks in a give river basin. The extended spatial scope allows to deal with wide ranges in geomorphological attributes, hydro-climatic conditions, and socio-economic status. Furthermore, we identify the relation of the findings with multiple factors related to human activities, such as the spatial distribution of human settlements, the degree of economy development, and the fraction of communities served by WWTPs. Generalizable patterns found in this study are expected to contribute to establishing viable management plans for recent water-environmental challenges caused by WWTP-discharges to river water bodies.

• The Journal of Engineering Geology
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• v.10 no.2
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• pp.52-74
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• 2000

The basement rock of upper stream of Keum River Valley consists of Precambrian gneiss which is resistant to weathering. That of mid and lower stream valley, however, is mainly composed of Mesozoic granites which are vulnerable to weathering. The upstream part of Geum River Basin is typified by the deeply-incised and steep meandering streams, whereas mid and lower part is characterized by wide floodplain and gently dipping river bottom toward the Yellow Sea. In particular flooding deposits, in which are imprinted a number of repetitions of erosion and sedimentation during the Holocene, are widely distributed in the lower stream of Geum River Basin. For understanding of erosions in the mid and lower stream of Geum River Basin, the rate of erosion of each small basins were estimated by using the data of field survey, erosional experiments and GIS ananlysis. It was revealed that erosion rate appeared highest in granite areas, and overall areas, in this field survey were represented by relatively high erosion rates. By implemeatation of remote sensing and imagery data, the temporal changes of river bed sediments for about last 11 years were successfully monitored. Observed as an important phenomenon is that the river bed has been risen since 1994 when an embankment (Dyke) was constructed in the estuarine river mouth. From the results derived from the detailed river bed topographical map made in this investigation, the sedimentation of the lower river basin is considered to be deposited with about 5 cm/year for the last 11 years. Based on this river bed profile analysis by HEC-6 module, it is predicted that Geum River bed of Ganggyeong area is continuously rising up in general until 2004. Although extraction of a large amount of aggregates from Gongju to Ganggyung areas, the Ganggyung lower stream shows the distinct sedimentation. Therefore, it is interpreted that the active erosions of tributary basins Geum drainage basins can affect general river bed rising changes of Geum River.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1183-1192
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• 2020

Economic analysis is a basic step in establishing disaster mitigation measures, but it is difficult to verify the results due to uncertainty. Therefore, the scope of investigation and analysis is wide. However, it is difficult to predict the amount of damage caused by flooding because the collection of relevant data is limited in the ungauged basin. In this study, distributed runoff analysis and flooding analysis were performed, and a method of estimating the amount of flood damage in the ungauged basin was proposed using collectible social and economic indicators and flood analysis results. For distributed runoff analysis and flooding analysis, GRM (Grid based Rainfall-runoff Model) and G2D (Grid based 2-Dimensional land surface flood model) developed by Korea Institute of Civil engineering and Building Technology were used. The method of substituting collectible social and economic indicators into the simple method and improvement method was used to estimate the amount of flood damage. As a result of the study, it was possible to estimate the amount of flood damage using satellite data and social and economic indicators in the ungauged basin.

• Journal of the Korean Geophysical Society
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• v.2 no.1
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• pp.9-26
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• 1999

The Ulleung Basin (Tsushima Basin) in the southwestern East Sea (Japan Sea) is floored by a crust whose affinity is not known whether oceanic or thinned continental. This ambiguity resulted in unconstrained mechanisms of basin evolution. The present work attempts to define the nature of the crust of the Ulleung Basin and its tectonic evolution using seismic wide-angle reflection and refraction data recorded on ocean bottom seismometers (OBSs). Although the thickness of (10 km) of the crust is greater than typical oceanic crust, tau-p analysis of OBS data and forward modeling by 2-D ray tracing suggest that it is oceanic in character: (1) the crust consists of laterally consistent upper and lower layers that are typical of oceanic layers 2 and 3 in seismic velocity and gradient distribution and (2) layer 2C, the transition between layer 2 and layer 3 in oceanic crust, is manifested by a continuous velocity increase from 5.7 to 6.3 km/s over the thickness interval of about 1 km between the upper and lower layers. Therefore it is not likely that the Ulleung Basin was formed by the crustal extension of the southwestern Japan Arc where crustal structure is typically continental. Instead, the thickness of the crust and its velocity structure suggest that the Ulleung Basin was formed by seafloor spreading in a region of hotter than normal mantle surrounding a distant mantle plume, not directly above the core of the plume. It seems that the mantle plume was located in northeast China. This suggestion is consistent with geochemical data that indicate the influence of a mantle plume on the production of volcanic rocks in and around the Ulleung Basin. Thus we propose that the opening models of the southwestern East Sea should incorporate seafloor spreading and the influence of a mantle plume rather than the extension of the crust of the Japan Arc.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.507-516
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• 2010

The purpose of this study is to propose the alternative development method by means of determining the optimal project size from the economic viewpoint, improving the existing method depending on engineering aspects. To this end, this study defined the flood mitigation projects as the production activities carried out by inputs and outputs, and proposed the alternative development method on the basis of optimizing input and output combinations. This paper, as the case study of the proposed method, developed alternatives for the flood mitigation planning of Youngsan River Basin by determining the optimal project scale. As the result of determining optimal project size, the net benefit of the optimal alternative tended to be dependent on the net benefits of the large individual proposals. Due to such problem, the effect of relatively small individual proposals are underestimated and possibly be excluded from the optimal alternative, which may result in exclusion of the potential damaged regions protected by them from the flood mitigation project. Thus for the selective flood protection by region, individual proposals need to be categorized into the global measures and local measures according to the flood protection area.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.5
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• pp.303-311
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• 2016

From having an experimental study of physical and consolidation characteristics of soft clay in Nakdong river lower basin, we come to the conclusion as follow. Clay minerals in Nakdong river lower basin are classified into Kaolinite and Illite. Water content($W_n$) is similarly distributed in a range of 50.4% to 92.8% in Noksan and 46.6% to 99.0% in Jangyu, and liquid limit(LL) of both areas appears lower than water content. In the case of compression index, the index of jangyu is a little higher than that of Noksan because Jangyu is in a range of 0.67 to 1.94 and Noksan in a range of 0.44 to 1.5. The second compression index of Jangyu in a range of 0.027 to 0.092 is also higher than Noksan in a range of 0.024 to 0.075. As a result of regression analysis, a relation between water content and compression index is linear, and between initial void ratio and compression index is shown to $C_c=0.80e_o-0.58$. The ratio of $C_{\alpha}/C_c$ in a range of 0.03 to 0.08 expresses a wide range.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.171-182
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• 2007

In this study, as a method for decreasing the confidence interval of the estimates of Clark hydrograph's concentration time and storage coefficient, regression equations of these parameters with respect to those of rainfall, meteorology, and basin characteristics are derived and analyzed using the Monte Carlo simulation technique. The results are also reviewed by comparing them with those derived by applying the Bootstrap technique and empirical equations. Results derived from this research are summarized as follows. (1) Even in case of limited rainfall events are available, it is possible to estimate the mean runoff characteristics by considering the affecting factors to runoff characteristics. (2) It is also possible to use the Monte Carlo simulation technique for estimating and evaluating the confidence intervals for concentration time and storage coefficient. The confidence intervals estimated in this study were found much narrower than those of Yoo et al. (2006). (3) A supporting result could also be derived using the Bootstrap technique. However, at least 20 independent rainfall events are necessary to get a rather significant result for concentration time and storage coefficient. (4) No empirical equations are found to be properly applicable for the study basin. However, empirical equations like the Kraven(I) and Kraven(II) are found valid for the estimation of concentration time, on the other hand the Linsley is found valid for the storage coefficient In this study basin. But users of these empirical formula should be careful as these also provide a wide range of possible values.

• Journal of the Korean earth science society
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• v.43 no.3
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• pp.405-429
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• 2022

Detrital zircon LA-MC-ICP-MS U-Pb dating of the Cretaceous Gurye Group, Gurye Basin, was carried out. Gurye Group consists of Supyeongri, Geumjeongri, Togeum, and Obongsan formations in ascending order, and five samples were collected for age dating. Based on the dating results, the lowermost Supyeongri and the uppermost Obongsan formations show narrow age ranges. Only Precambrian and Late Cretaceous zircons were found in the Supyeongri and Obongsan formations, respectively. However, the upper and lower Geumjeongri, and Togeum formations show wide age ranges from the Precambrian to Cretaceous. The youngest detrital zircon U-Pb ages of each formation except the Supyeongri Formation, which lacks Cretaceous zircon, were calculated to be ca. 107.4 Ma in the lower Geumjeongri Formation, ca. 104.6 Ma in the upper Geumjeongri Formation, ca. 97.7 Ma in the Togeum Formation, and ca. 88.5 Ma in the Obongsan Formation. Such results indicate that the depositional age of the Gurye Group can be constrained from the Lower Cretaceous Albian to the Upper Cretaceous Coniacian. Based on the distribution of the detrital zircon ages from each formation, the source area of the Gurye Group is interpreted to have been extended from the adjacent Youngnam Massif to the Okcheon Belt throughout the basin evolution. The increase of the Cretaceous zircon with time is thought to reflect the slab roll-back of the proto-Pacific plate during the Cretaceous.