• Title/Summary/Keyword: Basin Characteristics

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Evaluation of Groundwater Flow for the Kap-cheon Basin (갑천 유역의 지하수 유동 평가)

  • Hong, Sung-Hun;Kim, Jeong-Kon
    • Journal of Korea Water Resources Association
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    • v.40 no.6 s.179
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    • pp.431-446
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    • 2007
  • Groundwater flow in a basin is greatly affected by many hydrogeological and hydrological characteristics of the basin. A groundwater flow model for the Kap-cheon basin ($area=648.3km^2$) in the Geum river basin was established using MODFLOW by fully considering major features obtained from observed data of 438 wells and 24 streams. Furthermore, spatial groundwater recharge distribution was estimated employing accurately calibrated watershed model developed using SWAT, a physically semi-distributed hydrological model. Model calibration using observed groundwater head data at 86 observation wells yielded the deterministic coefficient of 0.99 and the water budget discrepancy of 0.57%, indicating that the model well represented the regional groundwater flow in the Kap-cheon basin. Model simulation results showed that groundwater flow in the basin was strongly influenced by such factors as topological features, aquifer characteristics and streams. The streams in mountainous areas were found to alternate gaining and losing steams, while the streams in the vicinity of the mid-stream and down-stream, especially near the junction of Kap-cheon and Yudeong-cheon, areas were mostly appeared as gaining streams. Analysis of water budget showed that streams in mountainous areas except for the mid-stream and up-stream of Yudeong-cheon were mostly fed by groundwater recharge while the streams in the mid and down-stream areas were supplied from groundwater inflows from adjacent sub-basins. Hence, it was concluded that the interactions between surface water-groundwater in the Kap-cheon basin would be strongly inter-connected with not only streams but also groundwater flow system itself.

Analysis of Wetness/Dryness in Geum River Basin based on Climatic Water Balance (기후학적 물수지에 의한 금강유역의 습윤/건조 상태 분석)

  • Kim, Joo Cheol;Lee, Sang Jin
    • Journal of Korean Society on Water Environment
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    • v.26 no.2
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    • pp.243-251
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    • 2010
  • Evapotranspiration and rainfall-runoff are the major components of hydrological cycle and thereby the changes of them can directly affect the wetness/dryness or runoff characteristics of basins. In this study the wetness/dryness in Geum river basin are classified by dint of cumulative probability density function of monthly moisture index and the long term changes of them are analyzed based on climatic water balance concept. The drought events in Geum river basin are selected through evaluation of monthly moisture index and the various hydrological properties of them are investigated in detail. Also the trends of time-series of climatic water balance components are examined by Seasonal Kendall test and the variability of hydrological cycle in Geum river basin during the recent decade is inquired. It is judged that the results of this study can be contributed to establishment of the counter plan against the future drought events as the fundamental information.

The design technique of the underwater anechoic basin in KRISO and its acoustic characteristics in ultrasound region. (무향 수조의 설계 기법 및 초음파 영역에서의 음향학적 특성)

  • 김시문;임용곤;이종무;박종원;최영철
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.350-355
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    • 2001
  • In order to verify the performance of acoustic-based communication systems, a reliable check-up method is needed, which simulates similar oceanic conditions in low cost. One of the possible candidates would be the performance test in an underwater anechoic basin producing no reflecting waves. For this purpose KRISO (Korea Research Institute of Ships and Ocean Engineering) have constructed an underwater semi-anechoic basin from 1999 to 2001. This paper describes its design procedure, especially, how the material and size of the absorbing walls were chosen. Experiments were also performed to check its anechoic quality, Comparing the results with simple analytical results we concluded that the anechoic basin is working well for some selected frequency ranges.

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MIXING PROCESS FLOW ANALYSIS OF PDM AND HYDRAULIC MIXING BASIN SYSTEM USING CFD (CFD를 이용한 펌프확산 및 수리낙차 방식의 혼화공정 흐름 분석)

  • Lee, S.W.;Chang, S.M.;Cho, Y.
    • Journal of computational fluids engineering
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    • v.22 no.1
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    • pp.1-7
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    • 2017
  • The mixing of water and chemicals is an important process in the water purification plant. In this paper, we compare PDM(pump diffusion mixer) and hydraulic mixer at the basin in the mixing process. The proper flow rates are predicted and compared in both mixers using CFD technique. As a result, the flow rate of purifier chemical liquid should be 5% of that of water for the optimal performance of mixing process. The characteristics of the two mixing methods are compared with each other for strong and weak points on the operation of the purification system, discussed in the view point of CFD simulations.

A Study on Run-off of Small Basins Representing the four major Rivers in Korea (소류역의 유출량에 관한 연구 (사대강을 중심으로))

  • 이석우;김시원;엄태영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.22 no.2
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    • pp.55-63
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    • 1980
  • To study run-off characteristics in the small watersheds in Korea, investigations had been carried out for a period of 4 years from 1972 to 1975 in the sample watersheds. The samples were selected in four major river basins such as the Han River, the Keum River, the Nakdong River and the Yongsan River. Water levels and rainfall data had been. collected from each sample area where the measuring instruments were installed. The findings of this investigation can be summarized as follows; 1. With an average runoff rate of 60% in the sample watersheds, the average runoff rate. in each sample proved to be as below; the Han River Basin : 41.4% the Keum River Basin : 61.7% the Nakdong River Basin : 69.4% the Yong San River Basin : 69.2% 2. The base flow rate in the sample watersheds proved to be 8.1 mm/month. 3. A comparison of the runoff obtained from actual measurements made and that calculated by the Kaijyama formula showed that the latter is 9.1% lower than the former.

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Attenuation of Peak Spectral Amplitude for the Vertical Displacement in the Kyungsang Basin (경상분지에서의 수직변위값에 대한 최대 스펙트럼 진폭의 감쇠)

  • 김성균
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1999.10a
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    • pp.45-51
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    • 1999
  • The attenuations of peak vertical displacements are studies using a conventional least squeare regression technique for microearthquakes occurred in the Kyungsang Basin southeastern Korea. The regression model applied to bandpass-fitered ground motion data includes parameters to account for geometric spreading anelastic attenuation depending on frequency source size and station site effects. Thirty nine displacement traces obtained by integrating velocity records for six shallow local microearthquakes are used to determine attenuation characteristics in the Basin. The regression result of the peak amplitude data leads to Q(f)=59.9 {{{{ {f }^{0.955 } }} for 1.5Hz$\leq$ f $\leq$ 25 Hz. It appears that the anelastic attenuation in the Kyungsang Basin is greater than that in the Western North America Area.

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Estimation of Probable Maximum Depth-Area-Duration by Moisture Maximization over the Geumgang River Basin (금강유역에 내린 호우의 수분최대화에 의한 가능 최대 DAD의 산정)

  • Lee, Kwang-Ho
    • Atmosphere
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    • v.16 no.2
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    • pp.55-65
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    • 2006
  • The characteristics of Depth-Area-Duration (DAD) for 50 storms over the Geumgang river basin have been analysed in terms of various storm causes using the precipitation data during the period from 1984 to 2003. Results show that the ratio of the precipitation depth to duration, and the ratio of decrease in the precipitation depth to area are the largest in the case of the tropical cyclone. Storm maximization ratios are in the range 1.03 to 2.66 for the 50 selected heavy precipitation cases over Geumgang river basin, with the largest value for the tropical cyclone case, suggesting that the tropical cyclone could cause heavier precipitation than the other storms. In addition, the 24-hour probable maximum precipitation for the Geumgang river basin is estimated to be about 745 mm in the maximum precipitation area.

Geomorphological Characteristics of the Miho Stream Flowing through a Granitic Plain, South Korea (화강암 분지를 흐르는 미호천의 지형학적 특색)

  • Kim, Young Rae
    • Journal of The Geomorphological Association of Korea
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    • v.28 no.3
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    • pp.1-11
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    • 2021
  • The drainage area of the Miho stream is composed of granitic basins, gneissic and sedimentary mountains. 80 percent of the Miho stream flows through the Jincheon basin and the Cheongju inner-plain within the Daebo granite belt. Because the deep weathering of granitic hills provides a large amount of sands to the streams, there are wide floodplains with thick alluvium developed in the basin and plain. The thickness of the alluvium is 5~10m and the width of the floodplains is 2~2.5km. In the basin outlet area where a stream passes through the mountain canyon, wide floodplains and deep alluvium are developed in other riverside. The Miho stream is a sand-gravel channel flowing through the Cheongju inner-plain with wide floodplains and deep alluvium formed by deep weathering of granite.

Slope Stability and Development of Debris Flow Deposit in the Ulleung Basin, East Sea (동해 울릉분지의 사면안정성 및 쇄설류 퇴적체의 발달)

  • Lee, Sun-Jong;Lee, Jeong-Min;Yoo, Dong-Geun;Lee, Go-Eun;Park, Soo-Chul
    • Economic and Environmental Geology
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    • v.50 no.2
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    • pp.129-143
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    • 2017
  • The shallow sediments in the southwestern Ulleung Basin consist of mass flow deposits such as slide/slump and debris flow deposits (DFD), caused by slope failure. These sediments are proven to be important in studying geological disaster and stability of the seafloor. In this paper, we analysised the flow accumulation and slope failure susceptibility of the Ulleung Basin on the basis of multi-beam data, collected in this area. We also studied the distribution pattern and the seismic characteristics of the DFD in the uppermost layer of the Ulleung Basin on the basis of seismic data. The slope susceptibility was calculated as the frequency ratio of each factors including slope, aspect, curvature and stream power index (SPI), which causes the slope failure. These results indicate that the slope failure is frequently to occur in the southern and western continental slope of the Ulleung Basin. The sediment flow (mass flow) caused by the slope failure converges to the north and northwest of the Ulleung Basin. According to the seismic characteristics, the uppermost layer in study area can be divided into four sedimentary unit. These sedimentary units develop from the south and southwest to the north and northwest in association with slope susceptibility and flow accumulation.

Physical Geographical Background of Geotourism Resources in Gumho River Basin (금호분지 내 지리관광자원의 자연지리학적 배경)

  • Son, Myoung-Won
    • Journal of the Korean association of regional geographers
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    • v.12 no.2
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    • pp.202-214
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    • 2006
  • In this paper Gumho drainage basin is divided into six geomorphic units (Bohyeon, Palgong, Biseul mountainous areas and Yeongcheon, Gyeongsan, Daegu basin), and physical geographical background and distributional characteristics of geotourism resources in each geomorphic unit are examined. Most(32 sites, 78%) of geotourism resources in Gumho basin reflect geomorphological environment, rest(7 sites, 17%) of them reflect geological environment. There are three geomorphological resources in Bohyeon mountainous areas, eight geomorphological resources in Palgong mountainous areas, and five geomorphological resources and one cultural resource in Biseul mountainous areas. There are two geomorphological resources, one geological resource, one biological resource, and two cultural resources in Yeongcheon basin. Among them one biological resource and and one cultural resource reflect local geomorphological environment. In Gyeongsan basin are there one geomorphological resource, three geological resources, and one biological resource, but one biological resource reflects local geomorphological environment. There are eight geomorphological resources, two geological resources, and three biological resources in Daegu basin. But two biological resources among them reflect local geomorphological environment.

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