• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.277-281
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• 2006

A study on stream-groundwater exchange was performed using head and temperature data of stream water, streambed, and groundwater. Groundwater level and temperature were obtained from multi-depth monitoring wells in small-scale watershed. In the summer time, time series of temperatrue data at streambed and groundwater were monitored for three months. In the winter time, we measured the temperature gradient between stream water and streambed. The observed data showed three typical types of temperature characteristics. First, the temperature of streambed was lower than that of stream water; second, the temperature of streambed and stream water was similar; and last, the temperature of streambed was higher than that of stream water. The interconnections between the stream and the streambed were not homogeneously distributed due to weakly developed sediments and heterogeneous bedrock exposed as bed of the stream. The temperature data may be used in formal solutions of the inverse problems to estimate groundwater flow and hydraulic conductivity.

• Journal of Korean Society on Water Environment
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• v.35 no.6
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• pp.539-549
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• 2019

In 2016, Benthic Macroinvertebrates Streambed Index (BMSI) was proposed as an index to evaluate streams as benthic macroinvertebrate depending on the substrate type of streambed. However, orignal BMSI were selected without consideration of water quality. Analyzes without water quality do not constitute biological indices based solely on the substrate type of streambed. Therefore, in this study, the indicator value was improvement in consideration of water quality, and the distribution characteristics of benthic macroinvertebrates according to the substrate type of streambed were analyzed under relatively equal water quality conditions. We surveyed 20,155 sampling units in Korea from 2008 to 2018, and we re-estimated each lithophility of 191 taxa. As a result of estimating the streambed of each newly lithophilic value classification group considering the water quality, it was different from the original lithophilic value. Representative integer lithophilic values were newly calculated from 126 taxa among the 191 index taxa used in the analysis. The correlation between new constructed BMSI and community structure was compared and analyzed. It showed extreamely significance (p<0.001) in the dominance index, diversity index, abundance index, and evenness index of the community structure. Diversity index, abundance index, and evenness index showed positive correlation, and dominance index showed negative correlation. The correlation coefficient (r) was the highest in the richness index of about 0.664.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.1-14
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• 2016

This study was conducted to develop a Benthic macroinvertebrates streambed index (BMSI) based on the response of the community to the substrate type of streambed. Analyzing the seasonal (Spring and Fall) data (11,367 sampling units) surveyed and collected during 2008~2014 at 960 sites in South Korea, we estimated the lithophility of 191 taxa. BMSI was composed of the lithophilic value, indicator weight value and individual abundance frequency. It showed an extremely significant correlation (r = -0.8, p<0.001) with the mean grain size (in phi-value) of the streambed.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.525-535
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• 2006

A study on stream-groundwater exchange was performed using head and temperature data of stream water, streambed, and groundwater. Groundwater level and temperature were obtained from multi-depth monitoring wells in small-scale watershed. During the summer and winter season, time series of temperature data at streambed and groundwater were monitored for six months. In the winter time, we measured the temperature gradient between stream water and streambed. The observed data showed three typical types of temperature characteristics. First, the temperature of streambed was lower than that of stream water; second, the temperature of streambed and stream water was similar; and the last, the temperature of streambed was higher than that of stream water. The interconnections between the stream and the streambed were not homogeneously distributed due to weakly developed sediments and heterogeneous bedrock exposed as bed of the stream. The temperature data may be used in formal solutions of the inverse problems to estimate groundwater flow and hydraulic conductivity.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.377-382
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• 2017

Field experiments were conducted to estimate streambed hydraulic conductivity at 15 sites in the Anseongcheon watershed, Korea. Seepage meters and piezometers were installed in the streambed at each site to measure the amount of stream water-groundwater exchange and the hydraulic gradient. The vertical hydraulic conductivity was then calculated using Darcy's formula. The measured stream water-groundwater exchange rates were $4.08{\times}10^{-6}$ to $1.49{\times}10^{-5}m/s$, and the vertical hydraulic gradients were 0.005 to 0.145. The data suggest the streambed hydraulic conductivity to be $7.80{\times}10^{-5}$ to $1.58{\times}10^{-3}m/s$. The results show significant differences in connectivity between stream and aquifer. Quantification of the hydraulic interconnection between stream and aquifer, and evaluation of the effects of groundwater development and utilization on the streamflow require hydrogeological investigations of the connection between stream and aquifer, including the hydraulic conductivity of the streambed. Various field testing and analysis methods for hydrogeological assessment also require further improvement.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.1
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• pp.103-108
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• 2008

Riverbed change is greatly influenced by artificial factors such as dam construction, gravel collection, and river improvement. This study simulated a long-term bed change based on the GSTARS3 model using actual data from the area downstream of the Geum River Daecheong Dam and compared the estimation with a section of the actual measurement. As a result, it was found that the section of the actual measurement was far lower than the result of the simulation in terms of long-term bed change. While the area downstream of Daecheong Dam displayed approximately an average of 2.29 m of streambed degradation on average while the upper stream area showed approximately 0.63 m of bed degradation over 24 years. In the simulation of the area downstream of Daecheong Dam based on the GSTARS3 model, similar bed degradation was observed. However, a great difference was detected between the result and the actual measurement. According to the cause analysis, the riverbed in the area downstream of Daecheong Dam has continuously degraded due to the dam construction and mass collection of gravel. The mass collection of gravel was the main cause of riverbed change. It was found that about 76% of all riverbed degradation was caused by the mass collection of gravel.

• Journal of Korean Society on Water Environment
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• v.39 no.4
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• pp.261-268
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• 2023

The benthic macroinvertebrates index (BMI) was developed based on the 5-day biochemical oxygen demand (BOD₅), which is the amount of biodegradable organic matter in stream water. However, benthic macroinvertebrates mainly live in the streambed substrate and are affected by the interaction of water quality and substrate. This study was conducted to examine the interactive relationship between water quality items (BOD₅, total phosphorus (TP), total suspended solids (TSS)) and substrate with BMI by performing statistical analyses (four-way analysis of variance, Pearson's correlation analysis, partial correlation analysis and multiple regression analysis). The data used in the analyses were collected from 19,915 sampling units at 1,937 sites in South Korea from 2010 to 2020. The interaction effect between BOD₅ and substrate types was confirmed through a four-way analysis of variance. Partial correlation analysis and multiple regression analysis estimated the degree of influence on the change in BMI value in the order of mean grain size of the substrate as (𝜱_m) > BOD₅ > TP > TSS. BMI can be regarded as an index that evaluates the comprehensive effects of water quality and streambed status, although it is an index that was developed based on the amount of biodegradable organic matter in a water column.

• The Journal of Engineering Geology
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• v.25 no.3
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• pp.413-420
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• 2015

Streambed hydraulic conductivity along the upper reaches of the Gongdo stage of Anseong Stream was estimated through measurements of stream-aquifer exchange rates (using a seepage meter) and vertical hydraulic gradients (using a manually driven piezometer). From the measured data, it was found out that the stream-aquifer exchange rates varied from -1.55 × 10^-6 to 1.77 × 10^-5 m/s, the corresponding vertical hydraulic gradient varied from -0.122 to 0.030, and the values of the streambed vertical hydraulic conductivity were estimated from 1.77 × 10^-5 to 1.97 × 10^-3 m/s, with variations representing local differences. The results are within the general range of streambed hydraulic conductivity values suggested by Calver (2001) and are slightly higher than values previously measured at other stream sites in Korea. The combined use of a drive-point piezometer and seepage meter (both constructed of high-strength stainless steel) is expected to be of practical use in the estimation of streambed hydraulic conductance, given the durability and portability of the instruments.

• Water for future
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• v.24 no.1
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• pp.99-107
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• 1991

This study is for simulating to the model which analyzes flow characteristics and transverse bed slopes in a coarse-streambed of the meandering alluvial channels. Using the equations for conservation of mass, momentum, and for lateral stability of the streambed, a linear differential equation of transverse bed slope is derived from the flow characteristics in curved channels. Its solutions are solved by the Sine-generated curve method(SCM) and compared with results of field measurements. Lag distances by the maximum transverse bed slope and velocity profiles will predict risk sections of concave bank under floods.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.3 s.116
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• pp.1-11
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• 2006

This study analyzed characteristics of natural and human environments in Chuncheon's Gongji stream, and suggested nature-friendly planning strategies for self-purification of water quality, biodiversity improvement and conservative waterfront recreation. The environmental analysis included streambed structures, floodplain soils, water quality, vegetation, wildlife, and human facilities. Natural colonization of vegetation for the middle section of the study stream was obstructed by a straightened concrete revetment of baseflow channel, and vehicle movement and concrete parking lots across the floodplain. These human disturbances also deteriorated the naturalness of the stream landscape and limited habitation of bird species. However, natural sedimented wetlands in half of the channel width for the lower section of the stream contributed to a desirable vegetational landscape and greater bird occurrence. Based on BOD measurements, water quality of the stream fell under class $II{\sim}III$ of the stream water-quality standard, but it was worse around sewage outlets due to incomplete sewage collection especially during the dry season. Dominant fish species included typical inhabitants of good water-quality streams that are tolerant of adverse habitat changes. Nature-friendly planning strategies were established based on analysis of the environmental characteristics. They focused on not merely spatial zoning and layout divided into four zones - preservation, partial preservation, conservation and use -, but close-to-nature channel revetment techniques, natural water-purification facilities, biotope diversification, and water-friendly recreation and circulation. Strategies pursued both renewal of stream naturalness and hydraulic stability of streamflow by minimizing transformation of natural channel micro-topography and biotope, and by reflecting natural traces of streambed structures such as revetment scour and sedimentation.