• Korean Journal of Heritage: History & Science
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• v.51 no.3
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• pp.4-31
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• 2018

It is difficult to ascertain exactly when the Hongjuupseong (Town Wall) was first constructed, due to it had undergone several times of repair and maintenance works since it was piled up newly in 1415, when the first year of the reign of King Munjong (the 5th King of the Joseon Dynasty). Parts of its walls were demolished during the Japanese occupation, leaving the wall as it is today. Hongseong region is also susceptible to historical earthquakes for geological reasons. There have been records of earthquakes, such as the ones in 1978 and 1979 having magnitudes of 5.0 and 4.0, respectively, which left part of the walls collapsed. Again, in 2010, heavy rainfall destroyed another part of the wall. The fortress walls of the Hongjuupseong comprise various rocks, types of facing, building methods, and filling materials, according to sections. Moreover, the remaining wall parts were reused in repair works, and characteristics of each period are reflected vertically in the wall. Therefore, based on the vertical distribution of the walls, the Hongjuupseong was divided into type I, type II, and type III, according to building types. The walls consist mainly of coarse-grained granites, but, clearly different types of rocks were used for varying types of walls. The bottom of the wall shows a mixed variety of rocks and natural and split stones, whereas the center is made up mostly of coarse-grained granites. For repairs, pink feldspar granites was used, but it was different from the rock variety utilized for Suguji and Joyangmun Gate. Deterioration types to the wall can be categorized into bulging, protrusion of stones, missing stones at the basement, separation of framework, fissure and fragmentation, basement instability, and structural deformation. Manually and light-wave measurements were used to check the amount and direction of behavior of the fortress walls. A manual measurement revealed the sections that were undergoing structural deformation. Compared with the result of the light-wave measurement, the two monitoring methods proved correlational. As a result, the two measuring methods can be used complementarily for the long-term conservation and management of the wall. Additionally, the measurement system must be maintained, managed, and improved for the stability of the Hongjuupseong. The measurement of Nammunji indicated continuing changes in behavior due to collapse and rainfall. It can be greatly presumed that accumulated changes over the long period reached the threshold due to concentrated rainfall and subsequent behavioral irregularities, leading to the walls' collapse. Based on the findings, suggestions of the six grades of management from 0 to 5 have been made, to manage the Hongjuupseong more effectively. The applied suggested grade system of 501.9 m (61.10%) was assessed to grade 1, 29.5 m (3.77%) to grade 2, 10.4 m (1.33%) to grade 3, 241.2 m (30.80%) and grade 4. The sections with grade 4 concentrated around the west of Honghwamun Gate and the east of the battlement, which must be monitored regularly in preparation for a potential emergency. The six-staged management grade system is cyclical, where after performing repair and maintenance works through a comprehensive stability review, the section returned to grade 0. It is necessary to monitor thoroughly and evaluate grades on a regular basis.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.425-437
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• 2007

Flow distribution of water and sedimentation rate were investigated to understand the hydrodynamics and settling characteristics of particulate materials in a constructed wetland for treatment of non-point sources pollutants, the Sihwa constructed wetland, Korea. The Sihwa constructed wetland is divided into three sub-wetlands(the Banwol, the Donghwa and the Samhwa wetlands) to treat the polluted water from three streams, the Banwol stream, the Donghwa stream and the Samhwa stream. From the results of water flow experiment using dye(Rhodamine 50WT Red), it was found that the water flow in the wetland was prevailing at the waterway and open water. Dye was spread slowly in the closed water area planted by plants. The mean hydraulic retention time(HRT) at the upper area of high wetland and lower wetland of Banwol, was found to be 34.1 hr at the upper area and 74.6 hr at the lower area respectively, totaling approximately 108.7 hr(4.5 days). The sedimentation rate was higher at lower area(sites of B, C and D) of the wetland than upper area(site of A which is settling zone). Based on the forecast for 20 years as to the amount of sediment that can be deposited in the open water in the future, the sediment depth of each area would be like this: A: 6.3 cm, B: 8.3 cm, C: 7.0 cm, D: 9.5 cm. The contents of organic materials in the sediment deposited within the sediment trap were found to be higher overly in the first investigation period which had much rainfall, and B, C and D areas were found to have an increased COD accumulation than A area. Also, nitrogen and phosphorus were found to increase in the down-stream of the wetland. The results of this study suggest that a sustainable research and management for the characteristics of water flow pattern and sedimentation changeable as time passes is needs to maintain or improve the efficiency of water treatment in the constructed wetland.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1193-1207
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• 2013

Increase of impervious area caused by overdevelopment has led to increase of runoff and then the problem of flooding and NPS were brought up. In addition, as decrease of base flow made groundwater level to decline, a stream that dries up is issued. low impact development (LID) method which is possible to mimic hydrological water cycle, minimize the effect of development, and improve water cycle structure is proposed as an alternative. As introduction of LID in domestic increases, the study on small watershed is in process mainly. Also, analysis of property of hydrological runoff and load on midsize watershed, like sewage treatment district, is required, the study on it is still insufficient. So, area applying LID practices from watershed of Dongrae stream is pinpointed and made the ratio and then expand it to watershed of Oncheon stream. Among low impact development practices, Green Roof, Porous Pavement, and Bio- retention are selected for the application considering domestic situations and simulated with SWMM-LID model of each watershed and improvement of water cycle and reduction of non-point pollution loads was analysed. Improvement of water cycle and reduction of non-point pollution loads were analyzed including the property of rainfall and soil over long term simulation. The model was executed according to scenario based on combination of LID as changing conductivity in accordance with soil type of the watershed. Also, this study evaluated area of LID application that meets the efficiency of conventional management as a criteria for area of LID practices applying to sewer treatment district by comparing the efficiency of LID application with that of conventional method.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.139-153
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• 2023

This study aimed to understand the spatiotemporal variations in nitrogen content in the Gyeongan stream along the main stream and at the discharge points of the sub-basins, and to identify the origin of the nitrogen. Field surveys and laboratory analyses, including chemical compositions and isotope ratios of nitrate and boron, were performed from November 2021 to November 2022. Based on the flow duration curve (FDC) derived for the Gyeongan stream, the dry season (mid-December 2021 to mid-June 2022) and wet season (mid-June to early November 2022) were established. In the dry season, most samples had the highest total nitrogen(T-N) concentrations, specifically in January and February, and the concentrations continued to decrease until May and June. However, after the flood season from July to September, the uppermost subbasin points (Group 1: MS-0, OS-0, GS-0) where T-N concentrations continually decreased were separated from the main stream and lower sub-basin points (Group 2: MS-1~8, OS-1, GS-1) where concentrations increased. Along the main stream, the T-N concentration showed an increasing trend from the upper to the lower reaches. However, it was affected by those of the Osan-cheon and Gonjiamcheon, the tributaries that flow into the main stream, resulting in respective increases or decreases in T-N concentration in the main stream. The nitrate and boron isotope ratios indicated that the nitrogen in all samples originated from manure. Mechanisms for nitrogen inflow from manure-related sources to the stream were suggested, including (1) manure from livestock wastes and rainfall runoff, (2) inflow through the discharge of wastewater treatment plants, and (3) inflow through the groundwater discharge (baseflow) of accumulated nitrogen during agricultural activities. Ultimately, water quality management of the Gyeongan stream basin requires pollution source management at the sub-basin level, including its tributaries, from a regional context. To manage the pollution load effectively, it is necessary to separate the hydrological components of the stream discharge and establish a monitoring system to track the flow and water quality of each component.

• Korean Journal of Organic Agriculture
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• v.19 no.3
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• pp.357-372
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• 2011

We carried out the experiment to select the suitable sprout soybean varieties for environment-friendly cultivation in paddy field of southern part area, compares of excess moisture injury degree and yield ability among 29 sprout soybean varieties. Plant growth of sprout soybean was generally low in beginning and recovered after flowering due to rainfall. In paddy field cultivation, number of pod per individual and number of seed per individual were less in difference than upland cultivation, and maturing date was delayed 5-14 days than upland cultivation in most species. When environment-friendly cultivation, pest injury was not caused major problem for the growth during the vegetative period of soybean due to ground spider as natural enemy to insect pest. However, damage of stink bugs showed severe during grain filling period, and Dawonkong, Anpyeongkong, Dachaekong and Wonhwangkong showed susceptible to sting bug. SMV infection was weak and showed some necrosis symptoms in Sokangkong, but black root rot was not infected at all. Bacterial pustule began to be infected slowly from pod enlargement stage in most species, displayed severe symptoms in Dawonkong, Pungsannamulkong, Seonamkong and Sobaeknamulkong. The symptoms of pod anthracnose, pod blight and purple spot were greatly appeared after flowering. Disease resistance varieties was Paldokong, Kwangankong, Doremikong, Somyeongkong, Pungsannamulkong, Iksa-namulkong, Seonamkong, Sojinkong, Pureunkong, Bosugkong, Namhaekong and Sorokkong. Lodging index showed 3 in Saebyeolkong, and other species displayed slight lodging in 0-3 degree. 100-seed weight is 9.8-17.2g extent and increased 0.1-3.7g than upland cultivation in most species, but decreased in some species. Government purchase standard, species correspond to small-seed-size namulkong (Sizing screen diameter 4.0-5.6 mm) was Dawonkong, Dachaekong, Bosugkong, Seonamkong, Sokangkong, Hannamkong, Somyeongkong and Wonhwangkong. Species which seed yield was higher than Pungsannamulkong (266kg/10a) were Sorokkong, Hannamkong, Bosugkong and Sowonkong. Considering sprout soybean species, disease endurance, insect resistance, lodging resistance, 100-seed weight, yield ability and excess moisture tolerances synthetically, Seonamkong, Hannamkong, Doremikong, Bosugkong, Pungwonkong, Kwangankong, Sowonkong, Dagikong, Paldokong, Eunhakong and Pungsannamulkong were promising for environment-friendly cultivation in paddy field.

• Journal of the Korean Society for Environmental Technology
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• v.19 no.6
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• pp.503-513
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• 2018

In order to continuous watershed management and improve water quality at Yeong-san river system, we analyzed and evaluated data on the monitoring of small stream in city and county boundaries within the watershed. In-period monitoring is estimated to be more frequent in the second quarter than the first quarter, so it should be considered when evaluating the target water quality by setting the target water quality. A small stream in the Yeong-san river system has higher concentration in the downstream area than the upstream area. As a result of calculating the load of the measuring point, Y.b B3(Pungyeongjeongcheon) and Y.b E1(Sampocheon) were high. The result of correlation analysis by monitoring point in order to evaluate the correlation between BOD and T-P items, BOD was highly correlated with COD and TOC, and was affected by emission of pollutants related to organic matter. T-P was highly correlated with SS and COD, and was affected by rainfall. This study will provide basic data and direction for designing efficient and scientific method for water quality management by analyzing accumulated water quality data by conducting long-term monitoring.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.419-431
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• 2021

In Seoul, it has been confirmed that the duration of rainfall is shortened and the frequency and intensity of heavy rains are increasing with a changing climate. In addition, due to high population density and urbanization in most areas, floods frequently occur in flood-prone areas for the increase in impermeable areas. Furthermore, the Seoul City is pursuing various projects such as structural and non-structural measures to resolve flood-prone areas. A disaster prevention performance target was set in consideration of the climate change impact of future precipitation, and this study conducted to reduce the overall flood damage in Seoul for the long-term. In this study, 29 GCMs with RCP4.5 and RCP8.5 scenarios were used for spatial and temporal disaggregation, and we also considered for 3 research periods, which is short-term (2006-2040, P1), mid-term (2041-2070, P2), and long-term (2071-2100, P3), respectively. For spatial downscaling, daily data of GCM was processed through Quantile Mapping based on the rainfall of the Seoul station managed by the Korea Meteorological Administration and for temporal downscaling, daily data were downscaled to hourly data through k-nearest neighbor resampling and nonparametric temporal detailing techniques using genetic algorithms. Through temporal downscaling, 100 detailed scenarios were calculated for each GCM scenario, and the IDF curve was calculated based on a total of 2,900 detailed scenarios, and by averaging this, the change in the future extreme rainfall was calculated. As a result, it was confirmed that the probability of rainfall for a duration of 100 years and a duration of 1 hour increased by 8 to 16% in the RCP4.5 scenario, and increased by 7 to 26% in the RCP8.5 scenario. Based on the results of this study, the amount of rainfall designed to prepare for future climate change in Seoul was estimated and if can be used to establish purpose-wise water related disaster prevention policies.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.3
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• pp.15-24
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• 2022

In 2000, a total of 23,794ha of forest was lost due to the East Coast forest fire, and about 70% of the damaged area was concentrated in Samcheok. In 2001, artificial restoration and natural restoration were implemented in the damaged area. This study was conducted to understand the current vegetation structure 21 years after the restoration of forest fire damage in the Samcheok, Gumbong Mountain area. As a result of classifying the vegetation community, it was divided into three communities: Quercus variabilis-Pinus densiflora community, Pinus densiflora-Quercus mongolica community, and Pinus thunbergii community. Quercus variabilis, Pinus densiflora, and Pinus thunbergii planted in the artificial restoration site were found to continue to grow as dominant species in the local vegetation after restoration. As for the species diversity index of the community, the Quercus variabilis-Pinus densiflora community dominated by deciduous broad-leaf trees showed the highest, and the coniferous forest Pinus thunbergii community showed the lowest. Vegetation in areas affected by forest fires is greatly affected by reforestation tree species, and 21 years later, it has shown a tendency to recover to the forest type before forest fire. In order to establish DataBase for effective restoration and to prepare monitoring data, it is necessary to construct data through continuous vegetation survey on the areas affected by forest fires.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.255-264
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• 2012

The stabilization using limestone ($CaCO_3$) and steel making slag as the immobilization amendments for Cu and Pb contaminated farmland soils was investigated by batch tests, continuous column experiments and the pilot scale feasibility study with 4 testing grounds at the contaminated site. From the results of batch experiment, the amendment with the mixture of 3% of limestone and 2% of steel making slag reduced more than 85% of Cu and Pb compared with the soil without amendment. The acryl column (1 m in length and 15 cm in diameter) equipped with valves, tubes and a sprinkler was used for the continuous column experiments. Without the amendment, the Pb concentration of the leachate from the column maintained higher than 0.1 mg/L (groundwater tolerance limit). However, the amendment with 3% limestone and 2% steel making slag reduced more than 60% of Pb leaching concentration within 1 year and the Pb concentration of leachate maintained below 0.04 mg/L. For the testing ground without the amendment, the Pb and Cu concentrations of soil water after 60 days incubation were 0.38 mg/L and 0.69 mg/l, respectively, suggesting that the continuous leaching of Cu and Pb may occur from the site. For the testing ground amended with mixture of 3% of limestone + 2% of steel making slag, no water soluble Pb and Cu were detected after 20 days incubation. For all testing grounds, the ratio of Pb and Cu transfer to plant showed as following: root > leaves(including stem) > rice grain. The amendment with limestone and steel making slag reduced more than 75% Pb and Cu transfer to plant comparing with no amendment. The results of this study showed that the amendment with mixture of limestone and steel making slag decreases not only the leaching of heavy metals but also the plant transfer from the soil.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.676-689
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• 2013

This study is to understand the current situation of Wonju Stream, which flows through Wonju, Kangwon-do, and Seom River, the national river located outside of Wonju, by investigating all river areas using biotope type. Also, this research looked into the relationship between biotope and appearance of wild birds by investigating the location of their appearance. Biotope groups are 'scale', 'shape', and 'landscape'. And, biotope types are 'moisture', 'physical environment', and 'existence of vegetation'. Biotope subtypes are 'river area', 'physical environment', 'vegetation type', and 'usage of land'. Seom River is classified as 21 different sections, and Wonju Stream is classified as 19 different sections. Wild birds are investigated on breeding season, which was January and May of 2008. By marking each bird's location of appearance, it figured out properties of biotope according to the location of bird's appearance. 31 species, 795 birds in spring were founded, and 49 species, 4,348 birds are founded in winter at Seom River area. Also, 34 species, 427 birds in spring, and 33 species, 3,442 birds are founded in winter at Wonju Stream area. In winter, 26 species, 547 birds, and in spring, 12 species, 72 birds at natural river with estuaries in confluence of Seom River area are founded. Also, 34 species, 1412 birds in winter, and 24 species, 341 birds in spring are founded at natural river with estuaries and wetland plants. This means that because agricultural rivers have wide river width, slow flow speed, and many different types of biotope, these rivers can be good habitats for wild birds. The precise investigations and classifications of biotope, which especially are hard for linear rivers, were done to understand the whole and current situation of rivers. Furthermore, the data that shows the locations of wild birds can basically be used for a recovery of biological habitats, a constructing of ecological streams, a river-maintenance, and an enhancement of biodiversity of Wonju. Also, because the types of biotope are altered by rain, a continuous monitoring for maintaining ecosystem of rivers are highly needed.