• Proceedings of the Korean Quaternary Association Conference
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• 2005.06a
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• pp.7-11
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• 2005

The soil erosion processes have estimated using spatial distribution of 137Cs radionuclide in Granite and Sedimentary Hillslopes in South Korea. The local variability of 137Cs inventory indicates that was related positively to organic matter content, clay content and water content and negatively to hydraulic permeability and slope gradient for bulk samples in different landforms within Granite and Sedimentary rock basins. The vertical variability of 137Cs inventory shows that most of 137Cs concentration and organic matter were accumulated between 0 and 2cms and gradually decrease with soil depth in incremental samples in both basins. The vertical variability of 137Cs inventories shows that 137Csinventories increase as we go to toward downslope in both basins. Finally, the soil loss values indicate that hillslope erosion processes are more intensive in Granite rock basin than those in Sedimentary rock basin.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.337-349
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• 1992

The Tertiary basins in Korea have widely been studied by numerous researchers producing individual results in sedimentology, paleontology, stratigraphy, volcanic petrology and structural geology, but interdisciplinary studies, inter-basin analysis and basin-forming process have not been carried out yet. Major work of this study is to elucidate evidences obtained from different parts of a basin as well as different Tertiary basins (Pohang, Changgi, Eoil, Haseo and Ulsan basins) in order to build up the correlation between the basins, and an overall picture of the basin architecture and evolution in Korea. According to the paleontologic evidences the geologic age of the Pohang marine basin is dated to be late Lower Miocence to Middle Miocene, whereas other non-marine basins are older as being either Early Miocene or Oligocene(Lee, 1975, 1978: Bong, 1984: Chun, 1982: Choi et al., 1984: Yun et al., 1990: Yoon, 1982). However, detailed ages of the Tertiary sediments, and their correlations in a basin and between basins are still controversial, since the basins are separated from each other, sedimentary sequence is disturbed and intruded by voncanic rocks, and non-marine sediments are not fossiliferous to be correlated. Therefore, in this work radiometric, magnetostratigraphic, and biostratigraphic data was integrated for the refinement of chronostratigraphy and synopsis of stratigraphy of Tertiary basins of Korea. A total of 21 samples including 10 basaltic, 2 porphyritic, and 9 andesitic rocks from 4 basins were collected for the K-Ar dating of whole rock method. The obtained age can be grouped as follows: $14.8{\pm}0.4{\sim}15.2{\pm}0.4Ma$, $19.9{\pm}0.5{\sim}22.1{\pm}0.7Ma$, $18.0{\pm}1.1{\sim}20.4+0.5Ma$, and $14.6{\pm}0.7{\sim}21.1{\pm}0.5Ma$. Stratigraphically they mostly fall into the range of Lower Miocene to Mid Miocene. The oldest volcanic rock recorded is a basalt (911213-6) with the age of $22.05{\pm}0.67Ma$ near Sangjeong-ri in the Changgi (or Janggi) basin and presumed to be formed in the Early Miocene, when Changgi Conglomerate began to deposit. The youngest one (911214-9) is a basalt of $14.64{\pm}0.66Ma$ in the Haseo basin. This means the intrusive and extrusive rocks are not a product of sudden voncanic activity of short duration as previously accepted but of successive processes lasting relatively long period of 8 or 9 Ma. The radiometric age of the volcanic rocks is not randomly distributed but varies systematically with basins and localities. It becomes generlly younger to the south, namely from the Changgi basin to the Haseo basin. The rocks in the Changgi basin are dated to be from $19.92{\pm}0.47$ to $22.05{\pm}0.67Ma$. With exception of only one locality in the Geumgwangdong they all formed before 20 Ma B.P. The Eoil basalt by Tateiwa in the Eoil basin are dated to be from $20.44{\pm}0.47$ to $18.35{\pm}0.62Ma$ and they are younger than those in the Changgi basin by 2~4 Ma. Specifically, basaltic rocks in the sedimentary and voncanic sequences of the Eoil basin can be well compared to the sequence of associated sedimentary rocks. Generally they become younger to the stratigraphically upper part. Among the basin, the Haseo basin is characterized by the youngest volcanic rocks. The basalt (911214-7) which crops out in Jeongja-ri, Gangdong-myon, Ulsan-gun is $16.22{\pm}0.75Ma$ and the other one (911214-9) in coastal area, Jujon-dong, Ulsan is $14.64{\pm}0.66Ma$ old. The radiometric data are positively collaborated with the results of paleomagnetic study, pull-apart basin model and East Sea spreading theory. Especially, the successively changing age of Eoil basalts are in accordance with successively changing degree of rotation. In detail, following results are discussed. Firstly, the porphyritic rocks previously known as Cretaceous basement (911213-2, 911214-1) show the age of $43.73{\pm}1.05$ 및 $49.58{\pm}1.13Ma$(Eocene) confirms the results of Jin et al. (1988). This means sequential volcanic activity from Cretaceous up to Lower Tertiary. Secondly, intrusive andesitic rocks in the Pohang basin, which are dated to be $21.8{\pm}2.8Ma$ (Jin et al., 1988) are found out to be 15 Ma old in coincindence with the age of host strata of 16.5 Ma. Thirdly, The Quaternary basalt (911213-5 and 911213-6) of Tateiwa(1924) is not homogeneous regarding formation age and petrological characteristics. The basalt in the Changgi basin show the age of $19.92{\pm}0.47$ and $22.05{\pm}0.67$ (Miocene). The basalt (911213-8) in Sangjond-ri, which intruded Nultaeri Trachytic Tuff is dated to be $20.55{\pm}0.50Ma$, which means Changgi Group is older than this age. The Yeonil Basalt, which Tateiwa described as Quaternary one shows different age ranging from Lower Miocene to Upper Miocene(cf. Jin et al., 1988: sample no. 93-33: $10.20{\pm}0.30Ma$). Therefore, the Yeonil Quarterary basalt should be revised and divided into different geologic epochs. Fourthly, Yeonil basalt of Tateiwa (1926) in the Eoil basin is correlated to the Yeonil basalt in the Changgi basin. Yoon (1989) intergrated both basalts as Eoil basaltic andesitic volcanic rocks or Eoil basalt (Yoon et al., 1991), and placed uppermost unit of the Changgi Group. As mentioned above the so-called Quarternary basalt in the Eoil basin are not extruded or intruaed simultaneously, but differentiatedly (14 Ma~25 Ma) so that they can not be classified as one unit. Fifthly, the Yongdong-ri formation of the Pomgogri Group is intruded by the Eoil basalt (911214-3) of 18.35~0.62 Ma age. Therefore, the deposition of the Pomgogri Group is completed before this age. Referring petrological characteristics, occurences, paleomagnetic data, and relationship to other Eoil basalts, it is most provable that this basalt is younger than two others. That means the Pomgogri Group is underlain by the Changgi Group. Sixthly, mineral composition of the basalts and andesitic rocks from the 4 basins show different ground mass and phenocryst. In volcanic rocks in the Pohang basin, phenocrysts are pyroxene and a small amount of biotite. Those of the Changgi basin is predominant by Labradorite, in the Eoil by bytownite-anorthite and a small amount pyroxene.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.161-169
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• 2012

Recently various attempts have been made to apply HSPF model to calculate runoff and diffuse pollution loads of stream and reservoir watersheds. Because the role of standard flow is very important in the water quality modelling of Total Water Pollution Load Management, HSPF was used as a means of estimating standard flow. In this study, BASINS 4.0 and WinHSPF was applied to the Gomakwoncheon watershed, genetic algorithm(GA) and influence coefficient algorithm were used to calibrate the runoff parameters of the WinHSPF. The objective function is the sum of the squares of the normalized residuals of the observed and calculated flow and it is optimized using GA. Estimates of the optimum runoff parameters are made at each iteration of the influence coefficient algorithm. The calibration results showed a relatively good correspondence between the observed and the calculated values. The standard flow(Q275) of the Gomakwoncheon watershed was estimated using the ten years of weather data.

• Journal of agricultural medicine and community health
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• v.4 no.1
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• pp.81-89
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• 1979

This study was undertaken to evaluate the present status of intestinal helminthic infection in rural areas of Korea from Dec. 1976 to Feb. 1979.The 4,311 stool specimens collected from 4 mountainous areas, 2 plain areas and 4 ri ver basins were examined. The methods employed were Kato's cellophane thick smear technique and brine fletation technique. The results are as follows. 1. The positive rate of intestinal helminch of any kind was 73.4%. It was 82.9% in river basins, 70. 2% in plain areas and 70. 4% in mountainous areas. 2. The positive rates of intestinal helmint.h were; Ascaris lumbricoides 42.5%, Trichocephalus trichiurus 51.4%, Hookworm 4.2%, Clonorchis sinensis 4.0%, Meta-gonimus yokogawai 5.7%, Hymenolepis nana 1.3%, Taenia species 1.0%, and Trichostrongyllus orientalis 1.2% respectively. 3. Sexual distribution of heiminthic infections showed higher rate in female than that of male except C. sinensis, H. nana, Taenia species, and. M. yokogawai. 4.Infection rates of T. trichiurus, Hook-worm and C. sinensis increased with age, but conversely H. nana were more prominent in younger age. 5. No geographical differen=e was noticed except that, M. yokogawai (20.9%), C sinensis (14.2%) in river basins ancl Taenia species (2.3%, by applying only stool examination) in mountainous areas were higher than the other 2 areas.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.235-238
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• 2003

In this study, we developed Open Water Management Program (OWMP) with an open architecture to deal with newly arising upgrade problems for a water management automation system. When we executed OWMP with data produced from an experimental field in Korea, the relative errors of this simulation were less than 5%. We developed runoff calculation model and verified it with measured data of 4 basins included in IHP. The relative errors came out less than 5% in all basins, except for one basin. We also applied OWMP to seongju irrigation reservoir to simulate daily runoff from 1998 to 2002, and the day, month, and year relative error between measured and simulated value was 0.25-0.05. Therefore the OWMP can be a tool nicely adapted to the optimal water management of irrigation reservoir.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.315-326
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• 1995

The layer charge characteristics of smectites from the Tertiary basins in the Pohang area have been studied in detail using the alkyl-ammonium method. On the basis of layer charges, the smectite in the Pobang area can be classed as normal and high-charge (hc) smectite. The layer charge of the normal smectite averages 0.3, and ranges from 0.25 to 0.38/half unit cell. The hc-smectite collapses on K-saturation to become illite-like material and shows $10{\AA}$-series reflections on X-ray diffraction. The layer charge of the he-smectite ranges from 0.5 to 1. The layer cbarges of the Pohang smectite are in general heterogeneous. The layer charges distribute between 0.21 and 0.45, and the most frequent layer charge is 0.30~0.32. The layer charge and the layer charge distribution do not appear to be related to stratification or basins of occurrence. Thus, the layer charge may not have developed as a result of burial. Rather, it may have developed due to heat and hydrothermal solutions associated with volcanic activities. Volcanic sills and dykes are ubiquitous in the region.

• Journal of Korea Water Resources Association
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• v.46 no.2
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• pp.123-137
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• 2013

This study investigated impacts of the two different types of El Ni$\tilde{n}$o on summer rainfall (June-September) in the Han River and its sub-basins. The patterns of rainfall anomalies show a remarkable difference between conventional El Ni$\tilde{n}$o and El Ni$\tilde{n}$o Modoki years. During conventional El Ni$\tilde{n}$o years, it was found that the Han River basins show decreases in the seasonal rainfall totals with high variations (CV=0.4). In contrast, during El Ni$\tilde{n}$o Modoki years, distinct positive anomalies appear in the Han River basin with a relatively small variation (CV=0.23). In addition, 11 out of 30 sub-basins show significant above-normal rainfall in southern part of the Han River Basin. For El Ni$\tilde{n}$o Modoki years, the number of heavy rainy days exceeding 30 mm/day and 50 mm/day were 9.9-day and 5.4-day, respectively. Consequently, this diagnostic study confirmed that El Ni$\tilde{n}$o Modoki has significant impacts on the variability of summer rainfall over the Han River Basin. We expect the results presented here provide useful information for the stability of the regional water supply system, especially for basins like the Han River Basin showing relatively high variability in seasonal rainfall.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.499-508
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• 2011

We analyzed the variations of water quality with flow regime alterations to determine the characteristics of the stream where the stream management is considerably difficult due to the high variability of the flow rates. In this study, both flow rates and water qualities were monitored at the tributaries, 34 in count, of both Geum River and Sabgyo Lake Basins. The variation of water qualities were divided into 2 types, based on their stream flow rates, known as Type I and Type II. If the water quality of a stream increases during low flow rate periods compared with high flow rate periods, it is classified as Type I; if the water quality of the stream increases during high flow rate periods compared with low flow rate periods, it falls under Type II. The analysis for the variations of water qualities, of all 43 basins, resulted to 24 basins under Type I and Nineteen 19 basins under Type II. The variations of water qualities were analyzed first by using Regression Analysis followed by Statistical Analysis. The average slope of the variations of water qualities and the slope of the standard deviations were 0.00135 and 0.00477, respectively. The Probability Distributions of both Type I and Type II basins were 61.1% and 38.9%, respectively. The basin having a probability distribution of 61.1% and is also known as Type I, increases during periods of low flow rates, due to the presence of point sources. Therefore, the basin should be enforced with stream management. Before the stream management can be implemented in all streams falling under Type II, the sources of contaminants should first be estimated. These contaminants can be classified into two parts, the first is Point source pollution and the second is Non-point source pollution, where the Non-Point source pollution can be sub-divided into two types, with storm runoff and without storm runoff.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.5
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• pp.69-78
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• 2009

In order to improve water quality of upper watershed of Paldang reservoir, it is necessary to evaluate non-point source pollution loads and identify critical watershed pollution sources. A GIS based Soil and Water Assessment Tool was applied to evaluate model application and reliability, estimate NPS pollution load, identify critical watershed by NPS pollution sources, and suggest various best management practices for Kyongan Stream watershed. Yearly NPS pollution loads were estimated 30.0% SS, 60.1% TN and 35.4% TP, respectably. The watershed pollution load is mainly decided by precipitation condition and SS and nutrients load have a significant regression relationship. Based on 10-year average yearly NPS pollution load, critical sub-watersheds were identified. The No. 5 and 17 which have lots of relatively intensive agricultural fields and scattered industrial area were vary critical sub-watersheds and under more intensive pollution load. In order to control critical watershed, watershed best management practices such as scientific fertilizer, contour farming and parallel terrace, transferring the sloppy farmland to grass or forest and constructing a buffer zone, and constructing wetlands and retention ponds will be applied. Overall the SWAT model can be efficiently used for identification of critical sub-watersheds in order to develop a priority watershed management plan to reduce water pollutions.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.201-213
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• 2007

In this study, the Batter Assessment Science Integrating point and Nonpoint Sources (BASINS 3.0)/window interface to Hydrological Simulation Program-FPRTRAN (WinHSPF) was applied for assessment of Soyang Dam watershed. WinHSPF calibration was performed using monitoring data from 2000 to 2004 to simulate stream flow. Water quality (water temperature, DO, BOD, nitrate, total organic nitrogen, total nitrogen, total organic phosphorus and total phosphorus) was calibrated. Calibration results for dry-days and wet-days simulation were reasonably matched with observed data in stream flow, temperature, DO, BOD and nutrient simulation. Some deviation in the model results were caused by the lack of measured watershed data, hydraulic structure data and meteorological data. It was found that most of pollutant loading was contributed by nonpoint source pollution showing about $98.6%{\sim}99.0%$. The WinHSPF BMPRAC was applied to evaluate the water quality improvement. These scenarios included constructed wetland for controlling nonpoint source poilution and wet detention pond. The results illustrated that reasonably reduced pollutant loadin. Overall, BASINS/WinHSPF was found to be applicable and can be a powerful tool in pollutant loading and BMP efficiency estimation from the watershed.