• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.1
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• pp.74-80
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• 2022

The vegetation of historical sites has been a form of vegetation that has remained since some years ago, but in modern times, vegetation and terrain have been deformed or damaged due to urban development, which was followed by an industrialization. As a solution to this, it is necessary to establish a plan for restoration and management by referring to the vegetation and landscape remaining in the historic site as indicators. This study was conducted to provide basic data for vegetation and landscape management of Baekje Historic Sites in Seoul by comparing and analyzing location characteristics, existing vegetation, and remaining vegetation of past substitutional vegetation for Pungnaptoseong and Mongchontoseong, Baekje Historic Sites in Seoul. As a result of the study, Pungnaptoseong and Mongchontoseong are located near the main stream of the Han River, Pungnaptoseong is located on a flat land consisting of natural embankments and floodplains, and Mongchontoseong is located on a hilly area. In the case of existing vegetation, it has been confirmed that Pungnaptoseong mainly has ornamental trees planting sites, while Mongchontoseong has a distribution of residual species from the past that grow in villages and hilly lowlands. The Substitutional vegetation of Pungnaptoseong and Mongchontoseong was synthesized based on the location characteristics and actual vegetation, it is estimated that the hilly areas may have been divided into "Quercus aliena Blume.", "Quercus mongolica Fisch. ex Ledeb." and so on, "Pinus densiflora Siebold & Zucc." on dry land,"Salix koreensis Andersson.", "Juglans mandshurica Maxim.", "Alnus japonica (Thunb.) Steud." in rivers and tributaries, "Quercus acutissima Carruth." in the main part of the forest, "Pinus densiflora Siebold & Zucc.", "Salix koreensis Andersson.", "Zelkova serrata (Thunb.) Makino." as a divine tree in the beginning of the village. Since the 1960s, all substitutional vegetation in the past has disappeared due to the introduction of foreign species and the creation of urban areas in Pungnaptoseong and Mongchontoseong, and the landscape has also been damaged. Fortunately, the substitutional vegetation was estimated in consideration of the species of residual trees distributed along the walls, climate, location characteristics, and times, but this study was conducted based on literature and existing vegetation surveys. Therefore, it is necessary to supplement the past target vegetation in Baekje historical sites in Seoul through quantitative experiments such as plant relic analysis in the future.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.103-113
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• 2023

The river confluence is a section in which two rivers with different topographical and hyrodynamic characteristics are combined into one, and it is a section in which rapid flow, inflow of sediments, and hydrological topographic changes occur. In the confluence section, the flow of fluid occurs due to the difference in density due to the type of material or temperature difference, which is called a density flow. It is necessary to accurately measure and observe the confluence section including a certain section of the main stream and tributaries in order to understand the mixing behavior of the water body caused by the density difference. A comprehensive analysis of this water mixture can be obtained by obtaining flow field and flow rate information, but there is a limit to understanding the mixing of water bodies with different physical properties and water quality characteristics of rivers flowing with stratigraphic flow. Therefore, this study attempts to grasp the density flow through the water temperature distribution in the confluence section. Among the extensive data of the river, vertical data and water surface data were acquired, and through this, the stratification phenomenon of the confluence was to be confirmed. It was intended to analyze the mixed pattern of the confluence by analyzing the water mixing pattern according to the water temperature difference using the vertical data obtained by measuring the repair volume by installing the ADCP on the side of the boat and measuring the real-time concentration using YSI. This study can supplement the analysis results of the existing water quality measurement in two dimensions. Based on the comparative analysis, it will be used to investigate the current status of stratified sections in the water layer and identify the mixing characteristics of the downstream section of the river.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.274-283
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• 2023

Buffer zones, an example of nature-based solutions, offer wide range of environmental, social and economic benefits due to their multifunctionality when applied to watershed areas promoting blue-green connectivity. This study evaluated the effects of buffer zone application to the water quality of Yongdam reservoir tributaries. Particularly, the challenges and improvement of the buffer zone design were identified and suggested, respectively. Water and soil samples were collected from a total of six sites in Yongdam reservoir from September 2021 to April 2022. Water quality analyses revealed that among the sites monitored, downstream of Sangjeonmyeon Galhyeonri (SG_W_D2) was found to have the highest concentration for water quality parameters turbidity, total suspended solids (TSS), chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN). This finding was attributed to the algal bloom observed during the sampling conducted in September and October 2021. It was found through the soil analyses that high TN and TP concentrations were also observed in all the agricultural land uses implying that nutrient accumulation in agricultural areas are high. Highest TN concentration was found in the agricultural area of Jeongcheonmyeon Wolpyeongri (JW_S_A) followed by Jucheonmyeon Sinyangri (JS_S_A) while the lowest TN concentration was found in the original soil of Sangjeonmyeon Galhyeonri (SG_S_O). Among the types of buffer zones identified in this study, Type II-A, Type II-B and Type III were found to have blue-green connectivity. However, initially, blue-green connectivity in these buffer zone types were not considered leading to poor design and poor performance. As such, improvement in the design considering blue-green network and renovation must be considered to optimize the performance of these buffer zones. The findings in this study is useful for designing buffer zones in the future.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.143-159
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• 2024

Natural aggregate is an essential resource for human activities, closely related to construction. The aggregate demand has been increasing annually, and due to the nature of the resource, it is difficult to procure from distant locations. This study identifies the distribution and characteristics of aggregate-bearing areas as part of a municipal-level aggregate resource survey conducted in Nonsan City, Korea, in 2023. Nonsan City is located approximately 35 km straight distance from the Geum River estuary and lies at the passageway of the main stream of the Geum River. The topography of Nonsan City features eastern mountainous areas and western plains, creating an east-high-west-low geomorphic setting, with 33 streams distributed across the city, including tributaries of the Geum River like Nonsan Stream, Noseong Stream, and Ganggyeong Stream. All streams originate from the highlands in the north and east, converge with Nonsan Stream, and then join the west bank of the main stream of the Geum River at the western boundary of Nonsan City. Drilling core results show shallow depths in the highlands to the north and east, deepening towards the west, reaching a maximum depth of 25 m near the main stream of the Geum River. The total reserve of land aggregates is calculated to be 246,789,000 m³, with a developable amount of 172,750,000 m³. The total reserve of river aggregates is 5,236,000 m³, with a developable amount of 3,765,000 m³. The distribution of aggregates varies according to the geomorphic, geologic, and development pattern of the river system. Reserves are scarce in mountainous areas but are abundant in regions with rivers and wide alluvial plains, although reserves appear at depths greater than 4m. The distribution of aggregate resources in Nonsan City is influenced by stream activities and sea level changes, with the tidal range of the Yellow Sea acting as an unfavorable condition for the preservation of aggregate resources.

• Korean Journal of Ecology and Environment
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• v.36 no.1 s.102
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• pp.21-28
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• 2003

Community composition and functional feeding groups of aquatic insects according to stream order were investigated from the Gapyeong Creek, a typical mid-sized Korean stream in Gyeonggi -do, Korea, in April 2000. For field investigations, the main watercourse and three major tributaries of the stream that belong to stream order ll to Vll were divided into reaches (ca. $1{\sim}4$ km in distance). Aquatic insects were sampled from one or two sites each reach (total 30 sites) using a Surber sampler ($50{\times}50$cm, mesh 0.75 mm). As a result of the quantitative samplings(two Surber samplings at riffle and pool/run per site; total $2{\times}30$=60 Surber samplings) and additional qualitative samplings, a total of 164 species of aquatic insects in 103 genera, 54 families, and 8 orders were collected from the stream. Those aquatic insects were composed of Trichoptera (56spp.: 34.1%), Ephemeroptera (43 spp.: 26.2%), Diptera (25spp.: 15.2%), Plecoptera (23 spp.: 14.0%), Coleoptera (6 spp.: 3.7%), Odonata (6 spp.:3.7%), Hemiptera (3 spp.: 1.8%), and Megaloptera (2 spp.: 1.2%); EPT-group (122 spp.:74.4%) or EPT-group plus Diptera (147 spp.: 89.6%) occupied most of the aquatic insect community; relatively larger number of species occurred in the mid-stream reaches (order III-Vl). The quantitative samplings throughout the study sites yielded a total of 26,286 individuals of aquatic insects ($136{\sim}2522$ inds./0.5 $m^2$, mean 906.4inds./0.5 $m^2$) that belongs to Ephemeroptera (11,994 inds.: 45.6%), Diptera (8730 inds.:33.2%), Trichoptera (4123 inds.: 15.7%), Plecoptera (1213 inds.: 4.6%), Coleoptera (204 inds.: 0.8%), Odonata (13 inds.: 0.05%), Megaloptera (5 inds.: 0.02%), and Hemiptera (4inds.: inds.: 0.02%); average number of individuals of aquatic insects increased as the stream order increased: average numbers of individuals of Bllecoptera and Trichoptera decreased and increased, respectively, as the stream order increased. Tolerant species such as Chironomidae spp., Uracanthella rufa and Hydropsychidae spp. were particularly abundant in the down stream reaches (order Vll) . Species diversity indices (H`) and dominance indices (Dl) were relatively higher and lower, respectively, in the mid-stream reaches (order $IV{\sim}VI$). Shredders occupied the smallest partand collector-gatherers were most abundant among the functional feeding groups(FFGs); collector-filterers considerably increased in the down stream reaches (orders Vl and VII); scrappers were relatively evenly distributed throughout the stream reaches: predators were relatively more abundant in the uppermost stream reaches(order ll) . Overall, the characteristics of aquatic insect comminity and FFGs in the Gapyeong Creek are largely similar to those in the normal streams of temperate deciduous forest in the northern hemisphere that is explained by the river confineum concept.