• 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.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.498-511
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• 2012

Mountainous wetland have many species such as II grade endangered species of wild flora and fauna(Drosera rotundifolia) and environmental indicator species(Utricularia racemosa, Habenaria linearifolia, Parnassia palustris, Molinia japonica, etc.). Accordingly, the mountainous wetlands is very important. However, most mountainous wetlands will disappear by natural or artificial aridness processes. Thus, it needs to manage mountainous wetland for protecting from aridness. This study has found out the wetland status of the environmental ecology and aridness processes moreover, it has suggested ways of improving wetland conservation plan and wetland aridness management plan. According to the results of topography structure survey, Hwaeom wetland's altitude is ranged within 750~810m(87.4%), and slope is less than $10^{\circ}$. There was ideally suited mountainous wetland. However, the water supply(1.6 meters depth and 0.8 meters wide) was built on under the wetland. For that reason, there was concerned about the aridness processes by sweeping away peat layer and dropping the water level. The distribution area of hygrophyte was narrowed to 6.7% whereas, woody plants and xerophytic plants was achieved a dominant position. If it leaves the situation as it is, the mountainous wetland will be developed next succession as forest ecosystem. Therefore, in order to sustain the mountainous wetland from aridness, it is set to the base direction of conservation and management as main schemes. Moreover, we have suggested that setting the vegetation conservation and management area which considering a ecological vegetation characteristics, managing the ecotone vegetation, setting the buffer zone for protection of ecological core areas, protecting the mountainous wetland indicator species and designating the management vegetation. In conclusion, in order to sustain and maintain a soundly wetland ecosystem, it needs to several management of wetlands damage factors. 1) suppression of the excessive groundwater to basin, 2) stabilization of wetland via hydrologic storage, 3) suppression of changing and transforming wetland into forest by succession via management of xerophytic plants.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.113-118
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• 2010

Due to diverse soil-forming environments and different purposes of the soil classification, numerous soil classification systems have been developed worldwide. The World Reference Base for Soil Resources (WRB) and the Soil Taxonomy of the United States are well-known in Korea. However, the German Soil Systematics based on somewhat different principles from the two former systems is little-known. The objective of this paper is therefore to give a short overview of the principles of the German Soil Systematics. The German Soil Systematics consists of a six-level hierarchical structure which comprises soil divisions, soil classes, soil types, soil subtypes, soil varieties, and soil subvarieties. Soils in Germany are firstly classified into one of four soil divisions according to the soil moist regime: terrestrial soils, semi-terrestrial soils, semi-subhydric/subhydric soils, and peats. Terrestrial soils are subdivided into 13 soil classes based on the stage of soil formation and the horizon differentiation. Semi-terrestrial soils are differentiated into four classes regarding the source of soil moist: groundwater, freshwater, saltwater, and seaside. Semi-subhydric/subhydric soils are subdivided into two classes: semi-subhydric and subhydric soils. Peats are classified into two classes of natural and anthropogenic origins. Classes can be compared to orders of the U.S. Taxonomy. Classes are subdivided into 29 soil types with regard to soil forming-processes for terrestrial soils, into 17 types with regard to the soil formation for semi-terrestrial soils, into five types with regard to the content of organic matter for semi-subhydric/subhydric soils, and also into five types with regard to peat-forming processes for peats. The soil mapping units in Germany are types, which can be additionally subdivided into ca. 220 subtypes, several thousands of varieties and subvarieties using detailed nuances of morphologic features of soil profile. Soil types can be compared to great groups of the U.S. Taxonomy.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.415-422
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• 2008

Pumping test was conducted to understand hydraulic conductivity for leaky confined aquifer with high permeability. Test aquifer was formed in $25{\sim}35\;m$ below ground surface at predetermined site of riverbank filtration which junction of Nakdong river and Milyang river in the Ttaan isle, Gimhae city, Korea Monitoring wells were located at intervals of 2 m and 5 m from pumping well in south-west direction (MW1 and MW2 wells) and northeast direction (MW3 and MW4 wells), respectively. Pumping test was continuously conducted for constant pumping rate of $2,500m^3/day$, hydraulic conductivity was estimated using AQTESOLV 3.5 program. Hydraulic conductivity were estimated to be $1.745{\times}10^{-3}m/sec$ for pumping well (PW), $2.452{\times}10^{-3}m/sec$ for between PW and MW1 wells, $2.161{\times}10^{-3}m/sec$ for between PW and MW2 wells, $2.270{\times}10^{-3}m/sec$ for between PW and MW3 wells and $2.591{\times}10^{-3}m/sec$ for between PW and MW4 wells. The function of hydraulic conductivity (K) as monitoring distance (d) were estimated to be logK = 0.0693logd - 2.671 for south-west direction (PW-MW1-MW2 line), logK = 0.0817logd - 2.655 for north-east direction (PW-MW3-MW 4 line). Scale exponent of hydraulic conductivity as test volume was estimated using Schulze-Makuch et al.(1999) method. Scale exponent of this aquifer was estimated to be 0.15. It means that test aquifer has very low heterogeneity. The radius of influence estimated using transmissivity, maximum groundwater level displacement, distance from pumping well and pumping rate during pumping test were 7.148 m for south-west direction and 6.912 m for north-east direction. The increasing rate of hydraulic conductivity from pumping well to maximum radius of influence were estimated to be 1.40 times for south-west direction and 1.49 times for north-east direction. Thus, heterogeneity of test aquifer was a little higher in north-east direction.

• Journal of Appropriate Technology
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• v.7 no.2
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• pp.136-143
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• 2021

Pacific island countries, including Kiribati, are suffering from a shortage of essential resources as well as a reduction in their living space due to sea level rise and coastal erosion from climate change, groundwater pollution and vegetation changes. Global activities to solve these problems are being progressed by the UN's efforts to implement SDGs. Pacific island countries can adapt to climate change by using abundant marine resources. In other words, seawater plants can assist in achieving SDGs #2, #6 and #7 based on SDGs #14 in these Pacific island countries. Under the auspice of Korea International Cooperation Agency (KOICA), Korea Research Institute of Ships and Ocean Engineering (KRISO) established the Sustainable Seawater Utilization Academy (SSUA) in 2016, and its 30 graduates formed the SSUA Kiribati Association in 2017. The Ministry of Oceans and Fisheries (MOF) of the Republic of Korea awarded ODA fund to the Association. By taking advantage of seawater resource and related plants, it was able to provide drinking water and vegetables to the local community from 2018 to 2020. Among the various fields of education and practice provided by SSUA, the Association hope to realize hydroponic cultivation and seawater desalination as a self-support project through a pilot project. To this end, more than 140 households are benefiting from 3-stage hydroponics, and a seawater desalination system in connection with solar power generation was installed for operation. The Association grows and supplies vegetable seedlings from the provided seedling cultivation equipment, and is preparing to convert to self-support business from next year. The satisfaction survey shows that Tarawa residents have a high degree of satisfaction with the technical support and its benefits. In the future, it is hoped that SSUA and regional associations will be distributed to neighboring island countries to support their SDGs implementations.