• Journal of the Korean Geographical Society
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• v.42 no.6
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• pp.879-897
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• 2007

The Royal District in Gyeungju-city was placed in lower surface of alluvial fan that was formed during the Last Glacial Age. During the Holocene, Bukcheon-river was reached in the dynamic equilibrium status and the form of river channel was similar or same to the present. The cases of dying people and carrying houses away by flood for ancient history in Gyeongju were six times, in 131, 160, 350, 496, 657 and 703. Like this big flood was happened at interval of $150{\sim}200$years. A period of big flood appearance in Bukcheon-river was extremely long. Therefore the people who had lived in Gyeongju for ancient history perceived that most part of riverbed of Bukcheon-river was a safety place from flood damages. Not only private houses. In east part of Bunhwangsa temple, that is, west side of Bukcheon-river where the river energy is maximum, a pillow block was built to prevent a lateral erosion but any artificial riverbank was not. In spite of high flood possibility in Bukcheon-river, there was no facility to prevent floods in this section. Also, deposits of flood are not identified. This point is very suggestive that Bukcheon-river did not flood for ancient history.

• Journal of the Korean Geographical Society
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• v.39 no.1
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• pp.56-69
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• 2004

We investigated the distribution and geomorphic development of alluvial fan in Gyeongju City including Cheonbuk area. According to a relative height to a river bed, alluvial fans of this area are divided into Higher surface, Middle surface, and Lower surface. As alluvial fans of Bulguk temple∼Ulsan bay area, the confluent fans in Cheonbuk and Gyeongju areas were formed by the Quaternary climatic change alternating glacial and interglacial stages, and the development of N-S and NW-SE fault lines. The Gyeongju alluvial fan, the largest in Korea, has been provided as the significant space for human activity since the prehistoric age. Bukcheon river formed the Gyeongju alluvial fan had not flowed over during the prehistoric and the ancient times. In contrast with general geomorphic characteristics, many springs in the Gyeongju alluvial fan are located in the middle part of the fan because ground water reaches to the surface. It is supposed that sedimental materials were not sufficiently piled up at lower reach of Bukcheon river due to the large deposits at upper and middle reach of the basin.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.6
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• pp.87-107
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• 2020

The purpose of this study is to present the basic data for maintenance and management of river ecosystem by surveying and analysing the kinds and their characteristics of vascular plants in Bukcheon stream, Gyeongju-si, South Korea. The numbers of vascular plants were summarized as 428 taxa including 92 families, 265 genera, 3 subspecies, 24 varieties, 6 forms, 5 hybrids and 5 cultivars. Among the identified taxa, there were 90 planted species. The endangered wild species was Cicuta virosa, and the rare plants were 5 taxa including Prunus × yedoensis, Juniperus chinensis L. var. sargentii and so on. The Korean endemic plants were 5 taxa Populus × tomentiglandulosa, Salix koriyanagi, Lespedeza maritima, Forsythia koreana and Aster pseudoglehni. The specific plants by floristic region were 26 taxa including 2 taxa of grade V, 3 taxa of grade IV, 2 taxa of grade III, 8 taxa of grade II and 11 taxa of grade I. The naturalized plants were 81 taxa including Euphorbia maculata, Erigeron strigosus, Vulpia myuros and so on. The invasive alien plants were 7 taxa including Humulus scandens, Rumex acetosella, Ambrosia artemisiifolia, Ambrosia trifida, Lactuca seriola, Symphyotrichum pilosum and Paspalum distichum.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.34 no.3
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• pp.67-77
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• 2016

This study was initiated from question raised on existing study achievement that purpose for Wolji construction simply was to build gardens. In this research, after raising a question on existing theory about the Wolji construction, another purpose of Wolji construction is investigated. Study result is as follows. First, two questions raised on Wolji construction are "Was Wolji constructed as a garden from the beginning?" and "Was Wolji region available land as now at time of creation?" However, it was verified that the purpose of Wolji construction was to use not as a garden but as a detention pond, and the land of such region was unserviceable at time of Wolji construction. Second, in terms of locations and Topography, it was confirmed that Wolji has a favorable condition for undercurrent function as it is positioned at the end point of flow path formed by gushout water spurting from the water flooded from Bukcheon, or low and wetland. Third, from hydraulic point of view, Bukcheon always has a possibility of flooding occurrence before completing river bank build up, and such flooding damage was curved at Guhwangdongwonji, and at Wolji once again in order to prevent the damage spread into the center of Wanggyeong. Fourth, from urban planning point of view, it was confirmed that urban functions were not established in Wolji region before Wolji construction, and urban planning was completed through the opening of roads and others, after Wolji construction. Fifth, it was confirmed that inflow and outflow device of Wolji, and vertical stone platform at western side of Wolji were the facilities to provide sufficient functions as detention ponds.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.390-401
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• 2022

This study investigated the characteristics of fish communities and inhabiting status of endangered species in the Bukcheon (Stream) of Seoraksan National Park, Korea from April to September 2020. A total of 4,356 fish of 7 families and 22 species were collected from 17 survey stations during the survey period. The dominant species was Zacco koreanus (relative abundance, 41.8%), and subdominant species was Rhynchocypris kumgangensis (relative abundance, 15.1%), followed by Pungtungia herzi (10.1%), Pseudopungtungia tenuicorpa (5.0%), Coreoleuciscus splendidus (4.1%), Zacco platypus (3.8%), Microphysogobio longidorsalis (3.5%), and Hemibarbus mylodon (2.2%). Among the fish species collected, 14 species (63.6%) were identified as Korean endemic species. There was one natural monument species (Hemibarbus mylodon), and four species of class II endangered wildlife that were designated by the Ministry of Environment (Acheilognathus signifer, Pseudopungtungi tenuicorpa, Gobiobotia brevibarba, and Brachymystax lenok tsinlingensis). Among the four species of class II endangered wildlife, B. lenok tsinlingensis inhabited in the upper stream, and A. signifer, P. tenuicorpa and G. brevibarba inhabited mainly in the middle-lower stream. Also, P. tenuicorpa, H. mylodon, and B. lenok tsinlingensis were inhabited in large numbers. Additionally, two cold-water fish species (R. kumgangensis and B. lenok tsinlingensis) and one landlocked species (B. lenok tsinlingensis) were collected. According to the results of cluster analysis, the dominance index decreased from upstream to downstream, but the diversity, evenness, and richness index increased; the cluster structure was divided into the uppermost, upstream, midstream, and downstream. The water quality of Bukcheon was evaluated as good overall since the river health (index of biological integrity) evaluated using fish was evaluated as very good (11 stations), good (2 stations), and normal (4 stations). However, river repair work was being carried out in some areas and some wastewater was flowing in from the midstream, therefore, supplementary measures to preserve fish habitats are required.

• Korean Journal of Ichthyology
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• v.27 no.4
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• pp.275-283
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• 2015

Habitat characteristics and feeding ecology of Iksookimia pacifica were investigated in this study to provide baseline data for its ecological characteristics in Bukcheon (stream), Goseong-gun, Gangwon-do, Korea. The main inhabit of I. pacifica was found to be sand bottoms of Bb or Bc river type with slow water flow. Based on studies of their habitat preferences according to age, their preference for sand bed was the same. However, their preference for depth and velocity was different. When their age was increased, their depth preference was also increased ($24.9{\pm}17.61cm$ for 0+ year, $69.6{\pm}30.32cm$ for 1+ year, $82.4{\pm}33.30cm$ for 2+ years, and $90.0{\pm}31.55cm$ for $3+{\leq}$ years). The water velocity was found to be 3.8 ~ 4.0 cm/sec for ages between 0+ and 1+ and 6.0 ~ 7.3 cm/sec for ages between 2+ and $3+{\leq}$. They were active on sand from March to November. They would hibernate in sand during the winter season. During the day from 12 pm to 24 am, they were highly active with high food consumption. Their main food sources analyzed with index of relative importance (IRI) include Chironomidae (76.7%), Simuliidae (10.3%), Rotatoria (7.3%), and Arcellidae (2.2%). Their juveniles (total length 20~40 mm) would feed on small-sized preys such as Rotatoria, Copepoda, and Arcellidae. Older I. pacifica would feed on big-sized preys such as Chironomidae and Simuliidae.

• Korean Journal of Ichthyology
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• v.33 no.2
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• pp.74-83
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• 2021

Distribution status, habitat characteristics, and extinction threat evaluation of the endangered species, Brachymystax lenok tsinlingensis were investigated in 2015 and 2019. Historical distribution reports of B. l. tsinlingensis were divided into before 1990, 1997~2006, 2000~2011, and 2010~2019. Among the 150 sampling sites investigated during the study period, number of individuals of B. l. tsinlingensis were collected 542 individuals from 67 sites. The streams inhabited of B. l. tsinlingensis were Naerincheon (11 stations), Odaecheon (11 stations), Bukcheon (10 stations), Bangtaecheon (8 stations), Songjeongricheon (4 stations), Suipcheon (3 stations), Inbukcheon (3 stations), Hyeondongcheon (3 stations) etc. The main habitat of B. l. tsinlingensis was upstream of the river with a high altitude of more than 400 m, 4~20 m water flow width, 1~2 m water depth, and high ratio (70~80%) boulder bottoms. The main reasons for the decline in population size were assumed as river works, construction of reservoirs and bridges, discharge of contaminated water into the river, the inflow of summer vacationers, and weir. Compared to our results there exists evidence that states a 20.7% reduction in occupancy within 10 years, in a small appearance range (7,732 km²) and occupancy area (268 km²), number of disconnected locations (15 locations), and a decline in habitat quality. Therefore, B. l. tsinlingensis is now considered as Near Threatened (NT) based on the results (Near meets VU A2acd, B1b(i,ii,iii)+B2b(i,ii,iii)) of IUCN Red List categories and criteria.

• Korean Journal of Ichthyology
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• v.31 no.1
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• pp.16-22
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• 2019

Investigations on the study of the distribution aspects and extinction threat evaluation of the Korean endemic species, Iksookimia pacifica were done from 2017 to 2018 in Korea. During the study period, the samples of I. pacifica were collected in 17 streams, 46 sites (from Baebongcheon Stream of Goseong-gun to Gunsuncheon Stream of Gangneung-si) among the noted 33 streams and 104 sampling sites investigated. The population size of I. pacifica was relatively large in streams such as Bukcheon, Baebongcheon, Hwasangcheon, Cheonjincheon, Ohhocheon Stream etc., but the population size was small in streams such as Sacheoncheon, Namcheon, Gangneung Namdaecheon Stream etc. The main habitat of I. pacifica was the downstream pool of clean water with slow velocity and sand bottoms, and their sensibility was estimated to be due to river work and water pollution. Comparing the previous records of the appearance of I. pacifica, they were first seen in Sampocheon Stream, but they did not appear in Jusucheon, Jeoncheon, Samcheok Osipcheon Stream. Given this evidence as noted for the 19.5% reduction in occupancy within 3 generations, in small appearance range ($1,343km^2$) and small occupancy area ($184km^2$), the number of locations were many (18) and the population was relatively large within the range of habitat. Therefore, I. pacifica is now considered a Near Threatened (NT) based on the IUCN Red List categories and criteria.