• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.117-128
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• 2010

The water qualities of Namdae-stream, Yeongok-stream and Sacheon-stream were examined, by using physicochemical factors, trophic status and epilithic diatoms from May 2008 to February 2009. The physicochemical water qualities of three streams were, except for some construction areas and sites of downstream, generally good, having less concentration than BOD of $2\;mg\;L^{-1}$. As for the sites of downstream, there were ongoing pollution such as graduation of nutrients in Namdae-stream and Sacheon-stream, due to salinity of seawater and topographical feature of the closed estuary. The examination of trophic status of Namdae-stream showed mesotrophic status in all the sites. Also, eutrophication was in progress as from the upstream to the downstream of Yeongok-stream, and Sacheon-stream showed eutrophic status in all its sites. As a result of the biological water quality assessment, Namdae-stream, excluding the downstream site, came out to be $\beta\sim\alpha$-oligosaprobic, and biological water quality was good, having TDI less than 50. Some construction sites and downstream site of Namdae-stream are $\beta$-mesosaprobic, and with the TDI over 70, the biological water quality assessment came out to be polluted. Yeongok-stream is $\beta\sim\alpha$-oligosaprobic, and its biological water quality is good, having TDI less than 40. Sacheon-stream, excluding the upstream site on May 2008 and February 2009, is $\beta\sim\alpha$-mesosaprobic, and its TDI over 70 shows that it has been polluted. The correlation analysis showed a high correlation in both DAlpo and TDI. Also, biological assessment of water quality (DAIpo, TDI) showed higher correlation with TSI rather than BOD.

• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.429-436
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• 2013

Churyeong Stream flows 37km from the mouth of Lake Okjeong and is impeded by many weirs that hamper the active movement of land-locked sweet smelt fish (Plecoglossus altivelis) that ascend and descend between the lake and the upper stream. In late December 2006, a fishway was constructed in a weir of the lower reach of Churyeong Stream, where juveniles begin their ascent to mature upstream. At 13 sites along the stream from April to October 2007, we investigated the effects of the newly constructed fishway on sweet smelt growth. After construction of the fishway, juvenile sweet smelt were able to migrate freely upstream, something that had previously only been possible when the weir was in flood. The body size of mature sweet smelt collected during the spawning season in September 2007 was greatly increased compared to previous seasons, measuring an average of $163{\pm}21.5mm$ in standard length. These measurements were 13mm, 20mm, and 57mm longer than body length averages for mature sweet smelt collected in 2006, 2004, and 2005, respectively. Therefore, it is likely to be necessary for the construction of fishways on streams and rivers containing land-locked sweet smelt populations to increase average body sizes and viability.

• Asian Journal of Turfgrass Science
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• v.12 no.1
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• pp.49-78
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• 1998

Nowadays, there are increasing demands of golf courses and it is necessary to make more golf courses than the present. To do this, we need to improve the environmental problems with the regional inhabitants, and it is said that the first thing to be considered in developing any golf course in Korea is to preserve the environment. In this context, the purpose of this study is to set forth several design factors to lessen the negative impacts which are accompanied with the development of golf courses. 1. The present conditions of golf courses in Korea Many new golf courses have come into being, particularly since the late 1980s, and now, in the year of 1997, over one hundred of golf courses are doing their business, yet the number of golf course is still less than required. So far, over a half of them have been made in the vicinity of Seoul on account of various reasons, and this has adversely affected on our natural environment. This unreasonable development of golf courses has caused serious water pollution, landslides and the other problems. Also, the topography of Korea is not good for golf courses. Although the demands of golf courses are increasing, the suitable sites for them are very limited, and therefore it is sometimes unavoidable to make golf courses on steep hills. Consequently, in designing golf courses in Korea, the most important thing is the balance between natural environment and artificial environment. 2.Eco-friendly golf course design factors 1) The concept of eco-friendly golf courses Ecologically sustainable and sound golf courses which are made by eco-friendly approaches 2)Basic conditions of eco-friendly golf courses (1)The most suitable sites (2) Conservation of existing ground as much as possible (3)Proper use of agricultural chemicals which have great impacts on the environment (4) Reasonable use of fertilizers (5) Developing a specialized fertilizer only for grass (6) Adaptation of organic agriculture (7) Improvement of grass sorts (8) Establishing reservoirs for purifying the water from golf courses 3) Eco-friendly golf courses (1) Location-Enough area /Gentle slope/Winding ground/Including lakes or streams /Not crossing wind's main direction Facing south or southeast /Suitable soIl for grass /Good drainage /Low level of underground water (2)Course layout and design -Consideration about existing contours as much as possible -Adaptation of Scotish design trend -Various holes' configuration -Consideration toward surrounding landscapes -Reducing grass areas -Giving buffer zones -Adapting computer methods in the process of site analysis and design (3) Eco-friendly considerations in constructing and managing golf courses -Protection of wildlife -Reuse of existing forests and preservation of topsoil -Renovation of old-fashioned courses -Reducing grass areas -Purification of water -Standization of management -Strict regulations against chemicals -Recycling organic materials -Through separation of the water inside golf courses and out of bounds -Getting proper construction works done in a due time 4.Eco-friendly considerations from a viewpoint of cultural environment 1) Well-matched landscape design and events planning 2) Implement of identifications and awarding systerns 3)Acknowledgement of superintendents' qualitications in the maintenance of golf courses 4)Increasing public golf courses and keeping good relationships with the neighbors near golf courses Key words: Pro-environmental development, Golf course.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.396-400
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• 2015

Enterobacteriaceae is one of the major families responsible for public health threats. Due to the emergence of pathogens with antibiotic resistance, great concern has been raised regarding the prevalence of antibiotic resistant bacteria in natural environments. Therefore, the diversity of Gram negative Enterobacteriaceae was investigated in water samples collected from five streams in Korea using the cultivation method. Profiling of multi-drug resistance was conducted with isolates via disk diffusion assay. The results indicated that the Gram negative Enterobacteriaceae consisted of the following genus; Citrobacter, Enterobacter, Escherichia, Klebsiella, Kluyvera, Pantoea, Plesiomonas, Raoultella, Shigella and Enterobacter. These latter strains represented 49% of identified isolates. In addition, 78.3% of the identified genus exhibited resistance against more than seven out of thirteen tested antibiotics, suggesting a high prevalence of multi-drug resistant bacteria in natural environments.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.652-655
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• 2013

Natural habitats of weedy melons were distributed on the islands along and on the west and south coasts of Korean peninsula including Boryeong, Seosan (Taean), Seocheon, Okgu, Buan, Gochang, Yeonggwang, Muan, Shinan, Haenam, Jindo, Wando, Goheung, Yeocheon, Hadong, Namhae, Goseong, Tongyeong, Geoje, and Jeju islands including Jeju city, Bukjeju-gun and Nam Jeju-gun. Weedy melons were found growing wildly in or around the cultivated lands in these regions. Natural habitats of weedy melons were in and around the cultivated lands. Weedy melon plants were found most often in soybean fields, followed by fields of mungbean, sweet potato, pepper, sesame, cotton, and peanuts. The plants were also found growing wild in foxtail millet fields, rice paddy levees along the streams, upland field edges, watermelon fields, corn fields, vegetable gardens near farmhouse, orange fields, compost piles, fallow fields, roadside and home gardens. They inhabited in sunny and a little dry spaces in relatively low-height crop plant fields in general. The time of fruit maturity was from early July to late October with the most frequency in September according to post survey answer. Fruits dropped off from the fruit stalk when matured. This phenomenon was thought beneficial for perpetuation in the wild. The fruits were being used commonly for food and toys for children. It was thought that weedy melons were perpetuating through the cycle of human and animal feeding of the fruits, human and animal droppings, often mixed in compost, and application of the compost to crop fields by human.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.365-376
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• 2021

In general, domestic streams and rivers are composed of alluvial rivers consisting of sand and gravel beds. These rivers can cause erosion and riverbed changes due to sudden changes in flow rates, such as floods, torrential rains, and heavy rains. In particular, there are various types of erosion, such as contraction erosion caused by changes in river shape, or local erosion occurring around obstacles such as piers, abutments or embankments. In addition, river changes can occur in various forms, such as static or dynamic periods, due to limitations such as flow rate, velocity, and shear stress. This study focused on the erosions of embankments directly related to human casualties among various river structures, and evaluated limit velocities and critical shear stress in order to identify changes in strength of natural materials by identifying the characteristics of natural hoan materials and resistance to erosions. In particular, the limitations of materials according to the type of materials in the river, characteristics of particles, and size of particles were studied using Soil loss, which is a change in the volume of the revetment material, and it is intended to be used as basic data for river design and restoration.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.3
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• pp.15-30
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• 2019

Changpo Lake was created as a part of a land reclamation for refugee self-helping projects. It shows characteristics of a fresh water lake, and still retains the early appearance of reclamation that surrounding regions have not been developed into farm lands. Shallow wetland has formed around the lake, which provides great conditions for diverse lives, and surrounding earthiness is favorable for growth of vegetation and restoration of the ecosystem. However, as facilities of the Muan International Airport nearby Changpo Lake are expanding and barns are being constructed, artificialness is gradually increasing. Particularly, since pollution sources such as sport facilities, farm lands and barns are scattered around Changpo Lake, pollutants are flowing in constantly. Accordingly, the results for setting up management areas according to the spatial characteristics and creating natural ecological spaces near Changpo Lake, Taebongcheon stream and Hakgyecheon stream are as follows. First, the creation of a natural eco-friendly waterfront space should be promoted by securing the health of the aquatic ecosystem and restoring species and the ecosystem. In addition, a consultative body needs to be formed to lead local residents to participating in river investigation and monitoring, maintenance, and management through role sharing. Second, the basic direction of the spatial management plan is to keep the unique charm of Changpo Lake, maintain harmony with nature, create diverse waterfront areas, and secure the continuity of Changpo Lake and inflow streams. Moreover, the area should be divided into three zones such as a conservation zone, a restoration zone and a waterfront zone, and for each zone, the preservation of vegetation, the creation of ecological wetlands and restoration of the ecotone and ecological nature need to be promoted. Third, facilities and activity programs for each space of Changpo Lake should be operated for efficient management of protected areas. In order to suit the status of each space, biological habitats, water purification spaces, experiential and learning spaces, and convenience and rest spaces should be organized and designated as research, monitoring, education, and tourism areas. Accordingly, points of interest should be set up within the corresponding area. In this study, there are many parts that need to be supplemented for immediate implementation since the detailed plans and project costs for the promotion of programs by area are not calculated. Therefore, it is necessary to make detailed project plans and consider related projects such as water quality, restoration of habitats, nature learning and observation, and experience of ecological environments based on the categories such as research, monitoring, education and tourism in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.321-335
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• 2023

Monitoring sediment loads in natural rivers is the key process in river engineering, but it is costly and dangerous. In practice, suspended loads are directly measured, and total loads, which is a summation of suspended loads and bed loads, are estimated. This study proposes a real-time sediment discharge monitoring system using the horizontal acoustic Doppler current profiler (H-ADCP) and support vector regression (SVR). The proposed system is comprised of the SVR model for suspended sediment concentration (SVR-SSC) and for total loads (SVR-Q_TL), respectively. SVR-SSC estimates SSC and SVR-Q_TL mimics the modified Einstein procedure. The grid search with K-fold cross validation (Grid-CV) and the recursive feature elimination (RFE) were employed to determine SVR's hyperparameters and input variables. The two SVR models showed reasonable cross-validation scores (R²) with 0.885 (SVR-SSC) and 0.860 (SVR-Q_TL). During the time-series sediment load monitoring period, we successfully detected various sediment transport phenomena in natural streams, such as hysteresis loops and sensitive sediment fluctuations. The newly proposed sediment monitoring system depends only on the gauged features by H-ADCP without additional assumptions in hydraulic variables (e.g., friction slope and suspended sediment size distribution). This method can be applied to any ADCP-installed discharge monitoring station economically and is expected to enhance temporal resolution in sediment monitoring.

• Journal of the Korean association of regional geographers
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• v.4 no.2
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• pp.31-47
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• 1998

This paper deals with the historical geography of land-use and agriculture along the Lower Nam-River floodplains. The reclamation process of the river floodplains, the cultivation methods on the reclaimed lands, and the land-use patterns and processes are investigated. The Nam River, one of the major tributaries of the Nakdong River, flows through the boundary between Ham-An and Eu-Ryong Guns. Larger floodplains are located in Ham-An Gun. The floodplains of Ham-An Gun have been surveyed intensively in this study. In South Korea, the alluvial plains, mostly located along the river valleys, have been reclaimed to provide fertile agricultural lands. Those along the upper river valleys were reclaimed before those along the lower river valleys. The flood-plains of Han-An Gun were reclaimed to be the largest agricultural lands of the Gun. The natural levees along the Lower Nam-River Valley were identified before the reclamation processes but now hardly identified. Relatively larger floodplains are located along the tributary streams of the Nam River. Often there are low-lying back swamps between the natural levees and the hills/mountains that rise above the floodplains. The back swamps, called 'natural bog lands' in this region, have been reduced in size and in number through reclamation for the purpose of agricultural and industrial land-uses. Now about ten 'natural bog lands' are found in the Ham-An floodplains, and some of them are being reclaimed for the industrial land-use. This study suggests the emergent need of conservation for the remaining 'natural bog lands' in terms of ecology. Seven agricultural fields of large size, originated from the Nam-River floodplains, are identified in this study: Kun(큰들), Chung-Am(정암들), Chang-chi(장지들), Baek-San(백산들), Ha-Ki(하기들), Gu-Hae(구혜들), and Chang-Po(장포들) fields. The Kun field was reclaimed during the Japanese control and the Gu-Hae, in the 1950s. All of those except the above two fields were reclaimed after the mid-1960s. The Nam-River Dam in Chinju, completed in 1969, contributed the reclamation processes along the Lower Nam-River floodplains. The rice acreage of the region has been reduced slowly since 1970 but the rice production of the region has been relatively stable (Table 4). Rice culture had been the most important agriculture on the reclaimed lands for decades before the greenhouse vegetable cultivation became more important in the 1980s. Among the vegetables cultivated in the greenhouse, the watermelon is the dominantly leading one. Watermelons are usually harvested two or three times in a year though it is possible to harvest four times in one year. The rotation of watermelons and rice is common in the region. It is known the physical conditions of the Nam-River floodplains in Ham-An Gun is the most suitable for watermelon cultivation in South Korea.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.311-321
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• 2018

The purpose of this study is to investigate effect of stream channel naturalness on ecological health by using environmental factors and Fish Assessment Index (FAI) in the Han River of South Korea. These samples and data have been released from the research project titled Stream/River Ecosystem Survey and Health Assessment, which was conducted in 444 sites in the Han river watershed from 2008 to 2016. All samples were classified into five groups according to a degree of morphological changes of stream. Water chemistry analyses indicated a decline in water quality by decreasing stream channel naturalness, it is assumed that channelized stream was vulnerable to aquatic pollution compared to the natural meandering stream. In the result of frequency of dominant species, sensitive species and insectivore such as Zacco koreanus, Rhynchocypris kumgangensis and Pungtungia herzi were frequently dominated in the natural meandering stream while tolerant species and omnivores such as Carassius auratus and Cyprinus carpio were more dominated in the channelized streams. The FAI in the channelized stream shows decline to average of $46{\pm}25$ compared with that of the natural meandering stream ($80{\pm}20$). The decrease in FAI was highly influenced by changes in matrixes of fish assemblage structure such as number of sensitive species (M3), portion of omnivores (M5) and insectivores (M6). Moreover, annual average FAIs from 2008 to 2016 were significantly correlated with water chemistry, especially TN, TP and BOD ($r^2=0.59$, p<0.0001). Taken together, all the results suggest that the stream channelization could negatively impact on the water quality and fish assemblage structure, leading to degradation in aquatic ecosystem health.