• International Journal of High-Rise Buildings
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• v.6 no.3
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• pp.261-269
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• 2017

Designed by star architect of Moshes Safdie, Raffles City Chongqing includes a total of 6 mega high-rise towers 250 to 380 m tall, a sky conservatory, a 5-storey high shopping mall and a 3-storey basement car parking. Located at the confluence of the Yangtze and Jailing Rivers, the site for the project is imbued with a significance that is immediately symbolic, both as a sign of Chongqing's important past and as a vivid indicator of the city's thriving present and future. The design for the project to be situated at this gateway takes as its governing idea the image of powerful sails upon the water. The outer facades of the project's eight towers - the transparent surfaces that will face the water to the north - are meant to recall a fleet of ancient Chinese ships, with their huge rectangles of white canvas filled by the wind. This is a $1.13million\;m^2$ mega scale integrated project of office, retail, hotel, service residence and high-end residence with the transportation hub and traffic circulation at various levels of the project. This paper presents the multi-dimensional hybrid design, engineering and construction of this mega scale project. The innovations and the cutting-edge technology used in this project are introduced and discussed benchmarking the design and construction of the skyscraper cluster in a major city like Chongqing of China.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.135-143
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• 2014

The variability and temporal trends of the annual and seasonal minimum and maximum temperature, rainfall, relative humidity, wind speed, sunshine hours, and runoff were analyzed for 5 major rivers in Korea from 1960 to 2010. A simple regression and non-parametric methods (Mann-Kendall test and Sen's estimator) were used in this study. The analysis results show that the minimum temperature ($T_{min}$) had a higher increasing trend than the maximum temperature ($T_{max}$), and the average temperature increased by about $0.03^{\circ}C\;yr.^{-1}$. The relative humidity and wind speed decreased by $0.02%\;yr^{-1}$ and $0.01m\;s^{-1}yr^{-1}$, respectively. With the exception of the Han River basin, the regression analysis and Mann-Kendall and Sen results failed to detect trends for the runoff and rainfall over the study period. Rapid land use changes were linked to the increase in the runoff in the Han River basin. The sensitivity of the evapotranspiration and ultimately the runoff to the meteorological variables was in the order of relative humidity > sunshine duration > wind speed > $T_{max}$ > $T_{min}$. Future studies should investigate the interaction of the variables analyzed herein, and their relative contributions to the runoff trends.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1135-1140
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• 2006

Concentration and speciation of trihalomethanes(THMs) and haloacetic acids(HAAs) that can be created during chlorine disinfection as disinfection by-products(DBPs) in Korean water treatment plants(WTPs) were investigated. 4 WTPs that adopted conventional water treatment processes were chosen for investigation and each represented a typical WTP on the Han, Keum, Sumjin and Nakdong Rivers. The average concentration of THMs was 26.9 ppb, and the maximum and minimum concentrations were 47.6 ppb and 11.0 ppb respectively, while the average concentration of HAAs was 25.4 ppb, and the maximum and minimum concentrations were 57.1 ppb and 9.7 ppb respectively. DBPs concentration was lower in the winter than the summer. The major species of THMs was chloroform and its average percentage was 77%, and the second highest was bromodichloromethane(20%), while the concentration of bromoform was below detection limits. The sum of dichloroacetic acid(DCAA) and trichloroacetic acid(TCAA) was 97% of $HAA_5 $ on average base. But its percentage was 90% in the Han River WTP, especially it was the lowest during the winter. On the other hand, the concentration of DCAA was higher than TCAA except during the summer.

• Journal of Korea Water Resources Association
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• v.52 no.6
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• pp.397-409
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• 2019

Gate operation of hydraulic structures is important for proper management in rivers. In this study, the characteristics of flood time were analyzed and predicted using the HEC-RAS model, which is capable of one-dimensional and two-dimensional connectivity analysis of the main points downstream of the Geum river. As a result, flood travel time was decreased once discharge increase and downstream water level rising. However, When the floodplain was overflowed, the arrival time increased due to the rapid increase of the river width. Also, the same condition, flood wave travel time at the major point was approximately twice as fast as water level rising travel time, indicating that waves progressed faster than actually water. Using the results of this study, it will be helpful in the river.

• Journal of Korean Society on Water Environment
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• v.16 no.4
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• pp.431-443
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• 2000

Water quality data from water treatment plants in Korea during 1994-1998 were investigated to find out the characteristics of their non compliance. The number of plants surveyed were approximately 600 and the number of samples were over 30,000. Ten parameters of water quality selected in this study and their non compliance % (inside parenthesis) were as follows: Heterotrophic plate count (0.14%), Total coliforms (0.08%), $NH_3$-N (0.29%), $NO_3$-N (0.14%), THMs (0.02%), Turbidity (0.11%), Residual chlorine (5.5%), $KMnO_4$ consumption (0.04%), Hardness (0.03%), pH (0.07%). These levels of non compliance were compared to those obtained from WIDB (Water Industry Database, 1996) of American Water Works Association. This study strongly supported that small water plants (<10,000 tons/day) were more vulnerable in meeting the regulation criteria of many water quality parameters such as Heterotrophic plate count. Total coliforms, $NO_3$-N, THMs, Turbidity, Residual chlorine, $KMnO_1$ consumption, Hardness and pH. The $NH_3$-N concentration was especially high in winter and its violation was frequently found in the specific areas such as the downstream of major rivers. The average THMs concentration was surprisingly low, indicating $13{\mu}g/L$ which is 43% of US. Accordingly, these characteristics must be reflected in establishing the effective management of water quality policy of drinking water in Korea.

• Journal of Environmental Impact Assessment
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• v.20 no.5
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• pp.685-695
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• 2011

Through the analyses of the distribution characteristics and management practices of the wildlife protection areas, this study intends to present basic data for improving the management of protected areas. 1) Based on the aggregate results of the protected areas, the average ratio of the metro-city and provincial areas to the designated protected areas was 1.49%; except for Chungcheongbuk-do (8.83%) and Gyeongsangnam-do (3.43%), most regions showed specified percentages of about 1%, whereby the analysis suggested that the designated protected areas were too small. 2) Considering the fact that most (86.16%) of the wildlife protection areas are in the regions that are of ecological nature level of grade 1, green nature level of grade 8 or better, and of legal conservation regions and districts, it was shown that these reserves are distributed in regions with excellent natural environmental conditions. 3) Designation of protected areas for the protection of wildlife and fish is deemed to be necessary. Although there are 588 wildlife & plant reserves, there are absolutely no designated areas for protecting plant and fish species. 4) Based on the results of an analysis of the current distribution by types, 92.47% of protected areas were concentrated in the mountains, 0.24% in the agricultural lands, and 7.29% distributed in the lakes/rivers/costal areas. 5) As major improvement projects, proposed were: advancement of management systems for protected areas, expanded designation of protected areas, overhaul of managed areas, designation of protected areas for the protection of wild plants and fish, need for management measures for private property and the surrounding areas, need to secure appropriate management personnel and collaboration, locally-adapted management, eco-information-based management, total management of protected areas, etc.

• 한국해양학회지
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• v.30 no.5
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• pp.413-425
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• 1995

Abundances and bacterivory of heterotrophic and mixotrophic nanoflagellates were investigated fourtimes between October 1993 and March 1995 in an estuarine system of the Mankyung and Dongjin rivers to understand distributions of nanoflagellates and ecological significance of bacterivory of nanoflagellates. Bacterivory of nanoflagellates were measured with fluorescently labeled bacteria (FLB). Heterotrophic and autotrophic flagellates showed a rage of 438-4,159 cells ml/SUP -1/ (mean of 2,145 cells ml/SUP -1/, n=20) and 971- 4,935 cells ml/SUP -1/ (mean of 2,2226 cells ml/SUP -1/, n-20), respectively. These two groups of nanoflagellates generally showed similar distributions of abundance. Abundances of heterotrophic nanoflagellates, known as major grazers of bacteria, and those of autotrophic nanoflagellates with chloroplasts showed statistically significant correlations with bacterial abundance (respectively, r$^2$=0.51 and r $^2$=0.47, p>0.05). Mixotrophic nanoflagellates seemed to comprise at least 4-23% of autotrophic nanoflagellate populations. Individual predation rates of heterotrophic nanoflagellates ranged from 2.2 to 14.2 bacteria flagellate/SUP -1/ h/SUP -1/ (mean of 4.9 bacteria flagellate/SUP -1/h/SUP -1/, n=16), and those of mixotrophic nanoflagellates from 1.6 to 9.7 bacteria flagellate/SUP -1/ h/SUP-1/ (mean of 3.7 bacteria flagellate /SUP -1/ h/SUP -1/, n=16). Bacterivory by mixotrophic nanoflagellates comprised from 30 to 69% of total nanoflagellates grazing on bacteria, indicating the significant role of mixotrophic nanoflagellates as grazers on bacteria in the study area. The ratios of grazing rates on bacteria to bacterial secondary production ranged widely from 0.06 to 1.23. In June, when abundances of total nanoflagellates were low, removal of bacteria by bacterivory of nanoflagellates was also a small fraction (0.08${\pm}$ 0.01, n=4) of bacterial production. In other seasons, nanoflagellates usually grazed on bacteria in significant fraction (0.06${\pm}$0.37, n=9) of bacterial production. Both heterotrophic and mixotrophic nanoflagellates appear to be major grazers on bacteria, and might transfer bacterial secondary production to higher trophic level in an estuarine system of the Mankyung and Dongjin rivers.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.237-237
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• 2015

The district of Marlborough has had more than its share of river management projects over the past 150 years, each one uniquely affecting the geomorphology and flood hazard of the Wairau Plains. A major early project was to block the Opawa distributary channel at Conders Bend. The Opawa distributary channel took a third and more of Wairau River floodwaters and was a major increasing threat to Blenheim. The blocking of the Opawa required the Wairau and Lower Wairau rivers to carry greater flood flows more often. Consequently the Lower Wairau River was breaking out of its stopbanks approximately every seven years. The idea of diverting flood waters at Tuamarina by providing a direct diversion to the sea through the beach ridges was conceptualised back around the 1920s however, limits on resources and machinery meant the mission of excavating this diversion didn't become feasible until the 1960s. In 1964 a 10 m wide pilot channel was cut from the sea to Tuamarina with an initial capacity of $700m^3/s$. It was expected that floods would eventually scour this 'Wairau Diversion' to its design channel width of 150 m. This did take many more years than initially thought but after approximately 50 years with a little mechanical assistance the Wairau Diversion reached an adequate capacity. Using the power of the river to erode the channel out to its design width and depth was a brilliant idea that saved many thousands of dollars in construction costs and it is somewhat ironic that it is that very same concept that is now being used to deal with the aggradation problem that the Wairau Diversion has caused. The introduction of the Wairau Diversion did provide some flood relief to the lower reaches of the river but unfortunately as the Diversion channel was eroding and enlarging the Lower Wairau River was aggrading and reducing in capacity due to its inability to pass its sediment load with reduced flood flows. It is estimated that approximately $2,000,000m^3$ of sediment was deposited on the bed of the Lower Wairau River in the time between the Diversion's introduction in 1964 and 2010, raising the Lower Wairau's bed upwards of 1.5m in some locations. A numerical morphological model (MIKE-11 ST) was used to assess a number of options which led to the decision and resource consent to construct an erodible (fuse plug) bank at the head of the Wairau Diversion to divert more frequent scouring-flows ($+400m^3/s$)down the Lower Wairau River. Full control gates were ruled out on the grounds of expense. The initial construction of the erodible bank followed in late 2009 with the bank's level at the fuse location set to overtop and begin washing out at a combined Wairau flow of $1,400m^3/s$ which avoids berm flooding in the Lower Wairau. In the three years since the erodible bank was first constructed the Wairau River has sustained 14 events with recorded flows at Tuamarina above $1,000m^3/s$ and three of events in excess of $2,500m^3/s$. These freshes and floods have resulted in washout and rebuild of the erodible bank eight times with a combined rebuild expenditure of $80,000. Marlborough District Council's Rivers & Drainage Department maintains a regular monitoring program for the bed of the Lower Wairau River, which consists of recurrently surveying a series of standard cross sections and estimating the mean bed level (MBL) at each section as well as an overall MBL change over time. A survey was carried out just prior to the installation of the erodible bank and another survey was carried out earlier this year. The results from this latest survey show for the first time since construction of the Wairau Diversion the Lower Wairau River is enlarging. It is estimated that the entire bed of the Lower Wairau has eroded down by an overall average of 60 mm since the introduction of the erodible bank which equates to a total volume of $260,000m^3$. At a cost of $$0.30/m^3$ this represents excellent value compared to mechanical dredging which would likely be in excess of $$10/m^3$. This confirms that the idea of using the river to enlarge the channel is again working for the Wairau River system and that in time nature's "excavator" will provide a channel capacity that will continue to meet design requirements.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.06a
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• pp.1-5
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• 2003

In order to prepare a basis for ecological restoration of the Seoul Metropolitan area, ecological diagnoses on soil physico-chemical properties and vegetation structure were carried out. Land use patterns, actual vegetation, and biotope patterns were also investigated based on aerial photograph interpretation and field checks. I formulated landscape elements overlaying those data and evaluated the ecological value of each element. Soil pollution was evaluated by analyzing soil samples collected in each grid on the mesh map, divided by 2km $\times$ 2km intervals. Soil samples were collected in forests or grasslands escaped from direct human interference. Soil pollution evaluated from pH, and SO$_4$, Ca, Mg, and Al contents of soil was more severe in the urban outskirts than in the urban center. Those soil environmental factors showed significant correlation with each other. Vegetation in the urban area was different in species composition from that in suburban areas and showed lower diversity compared with that in the suburban areas. Successional process investigated by population structure of major species also showed a difference. That is, successional trend was normal in suburban areas, but that in urban areas showed a retrogressive pattern. The landscape ecological map of Seoul indicates that the urban center lacks vegetation and greenery space is restricted in urban outskirts. Such an uneven distribution of vegetation has caused a specific urban climate and thereby contributed to aggravation of air and soil pollution, furthermore causing vegetation decline. From this result, it was estimated that such uneven distribution of vegetation functioned as a trigger factor to deteriorate the urban environment. I suggested, therefore, a restoration plan based on landscape ecological principles, which emphasizes connectivity and even distribution of green areas throughout the whole area of the Seoul to solve this complex environmental problem. In this restoration plan, first of all, I decided the priority order for connection of the fragmented greenery spaces based on the distances from the core reserves comprised of green belt and rivers, which play roles as habitats of wildlife as well as for improvement of urban environment. Next, I prepared methods to restore each landscape element included in the paths of green network to be constructed in the future on the bases of such preferential order. Rivers and roads, which hold good connectivity, were chosen as elements to play important roles in constructing green network by linking the fragmented greenery spaces.

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.29-36
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• 2014

The purpose of this study investigates the delivery characteristics according to the load of pollutants by calculating the delivery rate of targeted areas on pollutants in Sapkyo reservoir. The main rivers of Sapkyo reservoir are Namwoncheon, Dogocheon, Sapkyocheon, Muhancheon and Gokgyocheon. The delivery rate and their characteristics of five major rivers during rainfall season are investigated. As th result, biochemical oxygen demand (BOD), total nitrogen (T-N) and total phosphorous (T-P) of total delivery rate are calculated by 0.40, 0.34 and 0.08, respectively. The delivery rate of T-P compares to other water quality is investigated relatively low. Looked at the overall characteristics of the watershed, the delivery rate of T-N and T-P is little change in the rate of the year, too. The delivery rate of T-N is calculated from 0.2 to 0.3 in the dry season, and from 0.31 to 0.39 in a flood, respectively. The delivery rate of T-P is calculated to more than 0.3 in the dry season, and 0.11 in a flood. It is similar values which the average annual delivery rate of T-P is 0.08. Therefore, the measured delivery rate of Sapkyo reservoir can be applicable such as a delivery rate of similar features of the terrain and land use.