• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1287-1292
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• 2007

Recently, the frequency of unexpecting heavy rains has been increased due to abnormal climate and extreme rainfall. There was a limit to analyze 1D or 2D stream flow that was applied simple momentum equation and fixed energy conservation. Therefore, hydrodynamics flow analysis in rivers has been needed 3D numerical analysis for correct stream flow interpretation. In this study, CFD model on FLOW-3D was applied to stream flow analysis, which solves three dimenson RANS(Reynolds Averaged Navier-Stokes Equation) control equation to find out physical behavior and the effect of hydraulic structures. Numerical simulation accomplished those results was compared by using turbulence models such as ${\kappa}-{\varepsilon}$, RNG ${\kappa}-{\varepsilon}$ and LES. Those numerical analysis results have been illustrated by the turbulence energy effects, velocity of flow distributions, water level pressure distributions and eddy flows around the piers at Jangwall bridge in urbarn stream.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.29-30
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• 2018

Recent impervious pavements on roads and sidewalks cause rainwater to not penetrate into the ground, deplete groundwater, or flood the rivers, causing urban flood damage. In order to solve these problems, the amount of installed pitcher block is increasing, but the existing pitcher block is made with cement base and causes many problems. In the cement permeable block, the efflorescene phenomenon occurs due to the acid component, and the pore of the permeable block is clogged and the permeability is lost. As a result, the service life of the pitcher block is shortened and the replacement period is shortened. The purpose of this study is to analyze the basic properties of polymer concrete by replacing cement with polymer in order to solve the problem of cement - based concrete permeable block.

• Water Engineering Research
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• v.2 no.1
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• pp.33-48
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• 2001

For the design of suitable aquatic habitats and habitat management purposes, sensitive descriptors for aquatic areas were identified and analyzed. The classification system of the aquatic areas were developed for natural streams and modified streams in Korea. Relationships among the descriptors of an aquatic area such as channel width, meander wave length, and arc angle have been defined. The analysis indicates that the total mean sinuosity is 1.25 for the main channels of natural streams, whereas the mean value of the sinuosity of modified streams is 1.14. The mean values of the total area, the width, and the length for the sandbars of natural streams are larger than those of modified streams.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.5
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• pp.49-59
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• 2015

In this research, the connectivity status between natural environment (forests and rivers) and urban parks in view of ecological networks in a city is evaluated and on the basis of these evaluation results, a future connectivity enhancing recommendations are suggested. As a result, the 96.8% of the connectivity role of the neighborhood parks were core or connected parks and as in terms of the ecological pattern on the outer park, 84.1% of the case neighborhood parks were connected to the ecological element at least one side. Therefore, it can be expected to play a role as corridor that enables the direct connection with the natural environment if the connection plan is well established. As a result of connectivity evaluation of the parks, inside of the parks had low ecological element overall and had low connectivity, outside of the parks had 1.5 times more of low connectivity parks than high connectivity parks, and had similar disconnections such as facilities(fence, soundproof walls, breast walls, etc.), developments(roads, apartment complexes, industrial complexes, etc.), or poor greens regardless of the neighborhood with the ecological elements. To increase the connectivity of ecological network, the cities already built shall secure primarily green territory where can connect with the isolated park due to the surrounding with the developing areas and when planning for new cities or residential complexes, it shall establish a connection plan with the nearby at the beginning.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.40-48
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• 2008

The Waimea Basin is located on the northern tip of the South Island of New Zealand. It is a highly productive area with intense water use with multi-stakeholder interest in water. Irrigation from the underground aquifers here makes up the largest portion of used water; however the same aquifers are also the key urban and industrial sources of water. The Waimea/Wairoa Rivers are the main sources of recharge to the underlying aquifers and also feed the costal springs that highly valued by the community and iwi. Due to the location of the main rivers and springs close to the urban centre the water resource system here has high community and aesthetic values. Recent enhanced hydrological modelling work has shown the water resources in this area to be over allocated by 22% for a 1:10 year drought security for maintaining a minimalistic flow of 250 l/s in the lower Waimea River. The current irrigated land area is about 3700 hectares with an additional potential for irrigation of 1500 hectares. Further pressures are also coming on-line with significant population growth in the region. Recent droughts have resulted in significant water use cutbacks and the threat of seawater intrusion in the coastal margins. The Waimea Water Augmentation Committee (WWAC) initiated a three year stage 1 feasibility study in 2004/2005 into the viability of water storage in the upper parts of the catchment for enhancing water availability and its security of supply for consumptive, environmental, community and aesthetic benefits downstream. The project also sought to future proof water supply needs for the Waimea Plains and the surrounding areas for a 50 - 100 year planning horizon. The broad range stage 1 investigation programme has identified the Upper Lee Catchment as being suitable for a storage structure to provide the needs identified and also a possibility for some small scale hydro electricity generation as well. The stage 2 detailed feasibility investigations that are underway now (2007/2008), and to be completed in two years is to provide all details for progressing with the next stage of obtaining necessary permits for construction and commissioning a suitable dam.

• Journal of Korean Society of societal Security
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• v.3 no.1
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• pp.51-60
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• 2010

This study measured for comparison and analysis the correlation of River pollution and Soil contamination, based on the results of previous research, and then in order to increase the efficiency of study, heavy metals which cause serious side effects was limited to the case among pollutants. This study focused on the rivers that near the Urban and industrial districts, for example, Nak-Dong river, An-Yang river, Tae-Hwa river and the rivers that near the farm land or pasture, for example, Yeong-San river, Mi-Ho river, then compare and analyze the degree of actual pollution as gathered the results of Previous research. Correlationship about pollutants of river near the Urban, industrial area and drainage basin its river has been proven, and this expected because of the strong influence by point pollution source. On the other hand, I can found the opposite relationship where the river near the farm land or pasture, and this probably because of the influence by nonpoint pollution source.

• Journal of Ecology and Environment
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• v.48 no.1
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• pp.85-95
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• 2024

Background: In Korea, riparian zones and some floodplains have been converted into agricultural fields and urban areas. However, there are essential for maintaining biodiversity, as they are important ecological spaces. There are also very important spaces for humanity, as they perform various ecosystem services in a changing environment including climate change. Due to the importance of rivers, river restoration projects have been promoted for a long time, but their achievement has been insignificant. Development should be pursued by thoroughly evaluating the success of the restoration project. Ecological restoration is to accelerate succession, a process that a disturbed ecosystem recovers itself, with human assistance. Ecological restoration can be a test bed for testing ecological theories in the field. In this respect, ecological restoration should go beyond a 'simple landscaping exercise' and apply ecological models and theories in restoration practice. Results: The cross-section of the restored stream is far from natural rivers due to its steep slope and artificial material. The vegetation profiles of the restored streams did not reflect the flooding regime of the river. The species composition of the vegetation in the restored stream showed a significant difference from that of the reference stream, and was also different from that of an unrestored urban stream. Although species richness was high and the proportion of exotic species was low in the restored stream, the effect was offset by the high proportion of gardening and landscaping plants or obligate terrestrial plants. Conclusions: Based on both the morphological and ecological characteristics of the river, the restoration effect in the restored stream was evaluated to be very low. In order to solve the problems, a systematic adaptive management plan is urgently required. Furthermore, it is necessary to institutionalize the evaluation of restoration effects for the development of river restoration projects in the future.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.1
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• pp.11-18
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• 2000

Taegu is notorious as hot and dry summer among Korea cities. One of the most important goals of the open space planning is to ameliorate urban climate of the city. The objective of this research is to evaluate the thermal mitigation effect of the cool islands in Taegu metropolitan city. Cool islands of this paper includes parks and rivers surrounded by or adjacent to urbanized areas. Based on the analysis of the thermal band of Landsat TM at May 17, 1997, the thermal mitigation effect of open spaces in the city could be summarized as follows ; Kumho river showed the largest mitigation effect in terms of the width of mitigation zone and temperature difference. Evaporation from wide water surface and evapo-transpiration from riparian grass land could bring into results. Significant mitigation effect of parks covered with forest can be observed. The temperature range of such parks were between 19.05$^{\circ}C$ and 19.44$^{\circ}C$ However, the thermal mitigation effect of Dalsung park and Apsan park was insignificant. The small size and high percentage of hard paving of the former and the relative low density of the residential areas adjacent to the latter could be the main reason. In conclusion, the thermal mitigation effect in urban ope spaces could be detectedby the employment of thermal band data of Landsat TM and GIS buffering technique.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.55-75
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• 2017

The purpose of this study is to present the basic data for restoration of physical stream environment by analyzing habitat variables because habitat environment is changed due to the construction of waterfront space in urban streams. Assessment results of 10 habitat variables(three divisions) were almost same as optimal condition, in the reach of reference stream where there are no stream crossing structures and channel alteration. Assessment results of reaches in urban rivers, where streams were improved on water-friendly recreation activities, appeared to be marginal condition. Because habitat environment got worse due to stream improvement works such as construction of weir for water landscape, stepping stones for walking, low water revetment and high water revetment, and high water channel. In addition, in the case of mid gradient stream, the frequency of riffles was small or not existed because the intervals of the river crossing structures was short. In the case of mild stream types, the diversity of the pool was damaged due to the deposition of sludge in the upstream pool of weir and the installation of low water revetment.

• Journal of Environmental Science International
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• v.18 no.1
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• pp.113-127
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• 2009

This study was designed to present a river model with an aim at restoring the ecosystem and improving the landscape along the urban rivers on the basin of the Namhan river, a core life channel for the National Capital region. The revelation of botanical status, transition trend and correlation of plants might lead to providing the urban river restoration projects and ecological river formation projects with basic data for a model of ideal aquatic ecology and landscape. The outcomes of this study could be summed up as follows: 1. Communities of Juglans mandshurica, Cornus controversa and Fraxinus mandshurica constitute the main portion of flora at or around uppermost branch streams of the River Namhanis harbored mainly in and around small brooks 2. Typical terrestrial forest communities formed around the River Namhan are composed mainly of Larix leptolepis, Pinus rigida, planned forestation of Pinus koraiensis, Quercus acutissima, Quercus variabilis and Pinus densiflora. 3. The analysis into terrestrial environment of plant communities showed a high content of $P_2O_5$, typical communities found in the artificially disturbed land Finally, it seems also desirable to continue to make every exertion to explore the relationship between fluvial and terrestrial ecologies with a purport of building up a model of natural streams in urban area based on the surveyed factors for plant life, forest communities, soil and landscape and, moreover, on the forecasting for overall influences derived from the relation upon the ecosystem.