• The Journal of the Acoustical Society of Korea
• /
• v.19 no.3
• /
• pp.77-85
• /
• 2000

Laboratory determinations of acoustic and physical properties in Korea Strait sediment were carried out. Sediment sound velocimeter(SSV) was employed to measure the sound velocity of sandy sediment. Distribution patterns of the acoustic and physical properties are controlled by sediment texture. The study area is divided into three provinces(mid-shelf, shelf margin and enough) based on the acoustic and physical properties. This classification matches well with the previous result[14] based on the systems tracks and depositional systems. We suggest a geoacoustic model of the Korea Strait that replacing the old model of Briggs and Fisher[5].

• Journal of Korea Water Resources Association
• /
• v.46 no.1
• /
• pp.87-97
• /
• 2013

The bed change model of HEC-RAS was used to predict the formation of a delta upon an influx of high-density sediment while taking the particle-size distributions of the suspended sediment and bed materials into account. The model was able to reasonably predict both the spatial-temporal distribution of the delta and the amount of deposited sediment according to the grain size. In addition, it was able to estimate the main type of grains that sediment at particular locations at particular times moderately well. It is expected that the simulation and the analysis considering these particle-size distributions of sediment will provide important information on planning and maintenance of the water resource related facilities.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2007.05a
• /
• pp.1849-1853
• /
• 2007

In this study, flow-sediment discharge characteristics and relationships are estimated for the Cheonggyecheon basin, newly restored in 2005. Flow and sediment discharge measurement is performed on Ogansugyo, Majanggyo 2 and Yongdugyo during the rainy seasons in 2005-2006. The parameters of Clark UH are estimated using measured data, and sediment rating curves are derived by using grading and concentration analysis. Concentration time and storage coefficient of Clark UH are estimated 0.5 hr and 0.63 hr for Majanggyo 2, and 0.4 hr and 0.45 hr for Yongdugyo, respectively. Grain size of sediments are composed of fine silt to fine sand (0.008-0.25mm) based on the sediment grain size classification (Lane, 1947). Flow-sediment relationships derived by using concentration analysis shows that sediment discharge has no obvious relationship with flow discharge.

• Journal of Korea Water Resources Association
• /
• v.34 no.3
• /
• pp.199-207
• /
• 2001

Due to the nationwide development, sediment yield has to be estimated to design the sedimentation basin which is used to minimize the effects of construction or disturbing the natural soil condition. But there is no proved equation for the estimation of sediment yield in Korea. Therefore, applicability and the limitation of RUSLE (revised universal sediment loss equation) sediment yield equation is examined for the construction sites, where the rainfall and sediment data are available. General mistakes in estimation of the RUSLE parameters are also discussed. It is found that RUSLE could be applied in Korea as long as the sediment delivery ratio was considered. Appropriate estimation method of sediment delivery ratio are also proposed.

• Analytical Science and Technology
• /
• v.14 no.3
• /
• pp.238-243
• /
• 2001

The study was carried out to analysis of the pollutant $COD_{Mn}$, T-N, T-P for water quality proximated to sediment in lake of K river basin. water extracted from sediment showed higher $COD_{Mn}$, T-N, T-P datas than water proximated to sediment. Also, water proximated to sediment and water 5-10cm proximated to sediment showed the following data : $COD_{Mn}$, 1.2~1.9mg/L, T-N, 1.3~6.2mg/L, TP, 0.05~0.26mg/L, respectively. From this results, we have known the fact that the pollution degree of sediment have an effect on the water quality in lake and stream.

• Journal of Environmental Impact Assessment
• /
• v.11 no.4
• /
• pp.231-238
• /
• 2002

In this study we classified sediment types of tidal flat using Landsat-5 images. This is for groping the method which can analyze correctly various kinds of sediment faces through satellite images. This work was performed by referencing ground truth of sediment faces which was investigated in the field. With this data we classified Landsat-5 image of 1997's to grope a most suitable classification method. As a result, in case of south Kanghwa island area, it was the optimum way to compound band 4, 5, 7 of Landsat-5 TM imagery. And, this work classified 3 kinds of sediment faces - M(mud), sM(sandy mud) and (g)M(slightly gravelly mud) - in land and mixed water area. It is anticipated that if this method is applied to a image of extremely lower sea level time, it can classify the sediment types of a broad tidal flat area. This is expected to be a beginning of estimating the effect of sediment faces to the change of the tidal flat ecosystem.

• Korean Journal of Environmental Biology
• /
• v.29 no.1
• /
• pp.23-30
• /
• 2011

In this study, the Comet assay (evaluation of DNA damage) used the fish hepatocellular carinoma cell, PLHC-1, was tried to the sediment extract obtained from freshwater to understand its applicability as a tool for monitoring sediment toxicity. In parallel, induced EROD (7-ethoxyresorufin- O-deethylase) activity and DNA damage (TEM values) in PLHC-1 cells were measured for establishing the tandem endpoints of the PLHC-1cell test to test the ecotoxicity of sediment. Among several study sites in a small river passed through downtown and industrial park area, one of them, site B, showed a higher level of EROD activity and DNA damage than other sites. It indicates that a tandem endpoints of PLHC-1 cells could be useful tools for assessing the toxicity of sediment. The sensitivity of Comet assay with PLHC-1 cells was a little higher than that with a blood cell of frog tadpoles to the solvent extract of sediment. According to the results, a PLHC-1 cell-Comet assay could be used as a useful tool for evaluating ecotoxicity of the freshwater sediment. In addition, more detailed studies are needed to the contaminated site.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.38 no.3
• /
• pp.127-136
• /
• 1996

The purpose of this study is to provide with information for the water resources development and management in stream management planning, such as information on the sediment trensport, design of dam and water facilities, river improvement and flood plains management. The major results obtained from the field measurement and analysis of the watershed characteristics, hydraulic and sediment characteristics are as follows ; 1. The rating curve formulas obtained from the analysis of the hydraulic characteristics data collected are ; Q-=110.563 $(H-0.474)^2$ for 0.7m$(H-0.146)^2$ for 0.4m$Sr=aX{^2} {_1} X^{c}{_2}$, in the experimental watershed.

• Journal of Korean Society of Water Science and Technology
• /
• v.26 no.6
• /
• pp.43-51
• /
• 2018

In order to systematically and scientifically manage the organic and heavy metals against sediment at Daecheon Port, this study conducted particle composition, organic materials and heavy metals irradiation studies of sediments. Analysis of the grain size composition of sediments in the target study area showed the distribution characteristics of the mix of sand, silt and clay. That is, Station C (Stn. C) showed superior by fine-grained sediment, Station A and B (Stn. A and B) showed superior by coarse-grained sediment. The organic matter(COD, TOC, and IL) of Stn. C was appeared to be heavily polluted more than Stn. A and B. These data for the spatial properties in sediment showed that organic matter was related positively to the sediment silt-clay content. Also, in the case of heavy metals contamination in surface sediments, Stn. C was higher than Stn. A and B. Particularly, at the Stn. C, high organic matter concentration and C/N ratio value( >10) indicated that the sediment was composed highly of land-derived organic matter. From these results, it considered that the correlation analysis among to silt-clay, organic matter and heavy metal was found to have a good interrelationship.

• Journal of Sensor Science and Technology
• /
• v.30 no.1
• /
• pp.25-29
• /
• 2021

In this study, we successfully developed a highly reliable ultrasonic sediment sensor to detect the sediment levels in sewer pipes in harsh environments. The ultrasonic transducer employed in the ultrasonic sediment sensor was designed so as to possess a simple structure. The developed sensor was carefully optimized by simulating the electromechanical characteristics, radiated sound wave pressures, and directivity via finite element analysis. It was also designed to possess a simple mounting structure minimizing the flow disturbance in a 400-mm sewer pipe; additionally, eight ultrasonic transducers were arranged in a four-channel mode, allowing for measurement of the sediment height in five easy steps. Through experimental evaluations, we verified the performance of the ultrasonic sediment-level sensor and its industrial applicability. The results suggested that although the precision value was notably low at 15 mm, the sediment detection performance was adequate; therefore, the developed sensor can potentially be used in industrial applications.