• Title/Summary/Keyword: daedong river

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A Study on the Evaluation of Potential Hydro-electric Power in North Korea (북한의 수력발전가능량 산정 및 평가에 대한 연구)

  • Park, Miri;Ahn, Jaehyun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.38 no.1
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    • pp.41-49
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    • 2018
  • This study is to analyze and evaluate water resource development potential in North Korea. The study was conducted to analyze selected potential hydropower as an indicator to evaluate water resource development potential. Potential hydropower means theoretical value about the potential capacity of river. It is used to evaluate the amount of development through the hydropower generation. For calculating potential hydropower, monthly average and annual average of rainfall for each river basin were calculated by using the data of 27 rainfall stations in North Korea. As a result of the calculation of theoretical potential hydropower by rainfall in the seven major basins in North Korea, the Aprok River basin was analyzed to be the largest with $7,562.2{\times}10^3kW$. The efficiency and utilization rate of theoretical potential hydraulic power in South Korea and North Korea was 42.3% and 36.2%, respectively. The Daedong River basin's potential hydropower utilization rate is 12.3%, which is the lowest in North Korea. In the case of Daedong River basin, more than 40% of the total population is inhabited, so demand for water and electricity is expected to be the largest. Therefore, the Daedong River basin is considered as a priority area for water resource development. The results of this study are expected to be used as basic data for future water resource development projects and research activities in North Korea.

Origin and Stratigraphic Implication of Calcretes from the Gyeongsang Supergroup in the Vicinity of Ulsan City (울산시 부근의 경상누층군에 발달한 캘크리트의 기원과 층서적 의미)

  • Paik, In Sung;Lee, Joon Dong;Kim, Jeong Jin;Kim, In Soo;Kim, Hyun Joo
    • Economic and Environmental Geology
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    • v.31 no.5
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    • pp.431-446
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    • 1998
  • The calcretes from the Cretaceous Gyeongsang Supergroup in the vicinity of Ulsan city have been examined at five sites (Daedong, Seodong, Ansachon, Deogha, and Mangyangri). In these calcretes, evidences indicating pedogenic origin are recognized. Included are calcite aureoles around detrital grains, pedotubular pores, microstromatactis, circumgranular cracks, fitted structure of adjacent peloids, calcrete ooids, rhizocretions, and calcrete intraclasts. On the basis of calcrete development together with lithofacies, the depositional environments of those deposits are interpreted as lake margin (Daedong deposits), braided to low-sinuosity river (Seodong deposits), braid plain (Ansachon deposits), and meandering river (Deogha and Mangyangri). Stratigraphically, the fluvial deposits of study area show paleoenvironmental change from braided to low-sinuosity river plain under arid climatic condition to meandering river plain under seasonally wet an dry climatic condition. The stratigraphic successions of the Gyeongsang Supergroup of the study area Qacustrine-fluvial-Iacustrine) together with paleoenvironmental change of fluvial deposits suggest that those deposits can be correlated with the Banyaweol-Songnaedong-Geoncheonri formations of the Gyeongsang Supergroup in the western part of the Yangsan Fault.

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A Study on the Place Names Presented in the Area of Baekdu Mountain and Duman River of "Daedongnyeojido" ("대동여지도(大東輿地圖)" 백두산(白頭山).두만강(豆滿江) 일대에 표시된 몇 가지 지명(地名)의 검토 - 국경인식(國境認識), 위치(位置).어원(語源) 및 오기(誤記) 문제를 중심으로 -)

  • Lee, Kang-Won
    • Journal of the Korean association of regional geographers
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    • v.16 no.5
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    • pp.474-496
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    • 2010
  • In this article I try to investigate fifteen place names presented in the area of Baekdu mountain and Duman river of "Daedongnyeojido". The aims of the investigation are to clear Jeongho Kim's understanding on the national boundary implicated in the map, to search the etymology of the place names, and to analyze the place names miswritten. Through the investigation it will be suggested that the map presents the idea of 'Tomun river = Duman river = Bungye river', and recognizes 'Abrok river-Jeonggyebi-Duman river' as the landmarks of the boundary between Joseon(Korea) and Qing(China). Through the etymological analysis of the place names it will be suggested that some place names(Bundonggang, Geongatoi, Sihuasan, Geolodong and Daedong) originated from Nuzhen(Manchurian), the other place names(Gulsan and Guambong) originated from Korean. The location of the place names will be suggested also.

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Two-dimensional Numerical Modeling of Water Quality Variation by Gates Operation in the Seonakdong River (수문운영에 따른 서낙동강 수질변화에 관한 이차원 수치모의)

  • Lee, Namjoo;Kim, Young Do;Kwon, Jae Hyun;Shin, Chan Ki
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.1
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    • pp.101-112
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    • 2007
  • This study has used RMA2 model and RMA4 model, which are depth-averaged two-dimensional flow and water-quality prediction models, to analyze the variation of the water-quality by the gates operation in the Seonakdong River. Sensitivity analysis is performed to get the Manning coefficient and the coefficient of eddy viscosity for RMA2 model, and to get the diffusion coefficient for RMA4 model. Since the numerical simulation using RMA2 and RMA4 models did not consider tributary pollutant load except for that of Joman River, it could make a little difference from the natural phenomenon. Nevertheless, the numerical simulation shows that the discharge of $30m^3/s$, which is the continuous inflow from the Daedong-gate, can make it possible to achieve the target water-quality (BOD 4.3mg/L) of Nakbon-N watershed about 10 days later if the Daejeo-gate could remain opened in connection with the Noksan-gate operation.

A Study on the Pumping and Drainage Systems of the Floodplain at Daedong-myeon, Gimhae-si (김해시 대동면 범람원 지역의 양·배수 체계에 관한 연구)

  • HAN, Su-gyeong;SON, ILL
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.1
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    • pp.1-13
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    • 2011
  • The catch canal for a natural drainage, the excavation of tunnel for a stable irrigation, the artifical channelization of yazoo stream, many kinds of the pumping and drainage systems are found around Daedong-myeon, Gimhae-si. It could be confirmed that the deveolpment, maintenance and management of those facilities in the floodplain are mainly controlled by the geomorphological conditions. In case of Unha-chon, especially, the water can always be supplied only by openning the gate of irrigation tunnel and the Woldang pumping station as the largest pumping station in this area can supply water to Unha-chon area directly from the main river, Nakdong-gang. Because the Gamnae-chon which was an upper reach of the Unha-chon and is now connected to the Nakdong-gang through the Deoksan catch canal, the damage of flood and the burden of drainage are mitigated at the lower area of the Unha-chon.

Hydrogeological Characteristics of the Pyeongyang Area in the 1930s (1930년대 평양지역의 수리지질 특성)

  • Oh, Yun-Yeong;Hamm, Se-Yeong;Lee, Chung-Mo;Liang, Wei Ming;Kim, Gyoo-Beom;Kim, MoonSu
    • The Journal of Engineering Geology
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    • v.24 no.4
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    • pp.583-595
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    • 2014
  • The chemical properties and composition (pH, CaO, Fe, $HCO{_3}^-$, and $SO{_4}^{2-}$) of groundwater (GW) and surface water (SW) from the northern (non-carbonate bedrock) and southern (carbonate bedrock) sections of the Daedong River, Pyeongyang were analyzed and compared period of the 1930s. In the southern section, the GW and SW has a higher pH and $SO{_4}^{2-}$ concentration, but lower $HCO{_3}^-$ and Fe levels than in the north. This finding reflects a reaction that formed acid by replacing metal ions in inorganic salts by hydrogen, which resulted from the oxidation of organic material in a clay layer.

Standing Crop Distribution of Aquatic Plants in the West Nakdong River and Riparian Wetlands in the Nakdong River (서낙동강 본류 및 낙동강 둔치 습지의 수생식물 생물량 분포)

  • Kim, Gu-Yeon;Kim, Ji Yoon
    • Korean Journal of Ecology and Environment
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    • v.47 no.1
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    • pp.62-69
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    • 2014
  • Standing crop distribution of aquatic plants in the West Nakdong River and riparian wetlands in the Nakdong River were surveyed in May, July and September, 2010. Total 25 aquatic macrophyte species (submerged: 9, leaf-floating: 3, free-floating: 5, emergent: 8) were observed during the survey periods. Distribution area of aquatic plants and proportion of submerged communities were highest in Garakchi-deung ($212,032m^2$, 72.7%). The distribution area of aquatic plants was highest in Phragmites australis community ($421,584m^2$), followed by Hydrilla verticillata-Vallisneria natans community ($181,511m^2$), Potamogeton wrightii-Vallisneria natans community ($61,604m^2$), and Hydrocharis dubia community ($49,709m^2$). Garakch-ideung (212,032 kg) also had the highest aquatic plant production, followed by Suanchi-deung (15,546 kg), Daedong (5,813 kg), Dunchi-do (3,963 kg), Maekdo (1,463 kg), Yeommak (571 kg), Jungsa-do (530 kg), and Shinan (300 kg). Average standing crop of the study area were $147.8{\pm}20.8g\;DW{\cdot}m^{-2}$ in 1988, $96.1{\pm}20.0g\;DW{\cdot}m^{-2}$ in 2000, and $172.6{\pm}76.1g\;DW{\cdot}m^{-2}$ in 2010. For a sustainable management of river habitat and food source, aquatic plant should concurrently be surveyed with river environmental variables (i.e. sediment, nutrient, flow).

Evaluating Applicability of SRTM DEM (Shuttle Radar Topography Mission Digital Elevation Model) in Hydrologic Analysis: A Case Study of Geum River and Daedong River Areas (수문인자추출에서의 SRTM DEM (Shuttle Radar Topography Mission Digital Elevation Model) 적용성 평가: 대동강 및 금강 지역 사례연구)

  • Her, Younggu;Yoo, Seung-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.6
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    • pp.101-112
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    • 2013
  • Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) offers opportunities to make advances in many research areas including hydrology by providing near-global scale elevation measurements at a uniform resolution. Its wide coverage and complimentary online access especially benefits researchers requiring topographic information of hard-to-access areas. However, SRTM DEM also contains inherent errors, which are subject to propagation with its manipulation into analysis outputs. Sensitivity of hydrologic analysis to the errors has not been fully understood yet. This study investigated their impact on estimation of hydrologic derivatives such as slope, stream network, and watershed boundary using Monte Carlo simulation and spatial moving average techniques. Different amount of the errors and their spatial auto-correlation structure were considered in the study. Two sub-watersheds of Geum and Deadong River areas located in South and North Korea, respectively, were selected as the study areas. The results demonstrated that the spatial presentations of stream networks and watershed boundaries and their length and area estimations could be greatly affected by the SRTM DEM errors, in particular relatively flat areas. In the Deadong River area, artifacts of the SRTM DEM created sinks even after the filling process and then closed drainage basin and short stream lines, which are not the case in the reality. These findings provided an evidence that SRTM DEM alone may not enough to accurately figure out the hydrologic feature of a watershed, suggesting need of local knowledge and complementary data.

Distribution Changes of Freshwater Microalgae Community in the Nakdonggang River, Korea (낙동강 담수 미세조류 군집 분포 변화)

  • Suk Min Yun;Dae Ryul Kwon;Mirye Park;Chang Soo Lee;Sang Deuk Lee
    • Journal of Korean Society on Water Environment
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    • v.39 no.2
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    • pp.181-193
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    • 2023
  • Distribution changes in microalgae communities were studied in the Nakdonggang River at two sampling stations (St.1 Gyeongcheongyo Bridge (GB) and St.2 Daedong Wharf (DW)) at monthly intervals from January 2021 to November 2021. A total of 83 taxa included 82 species, 1 forma, belonging to 49 genera, 32 families, 21 orders, and 8 classes. The most important groups were Bacillariophyta and Chlorophyta. The number of species ranged from 5 to 24 in GB, and from 9 to 21 taxa in DW. The contribution of Bacillariophyta to the total species richness was the highest during all survey periods, and Chlorophyta yielded the next highest value in the study area. The dominant taxa were Aulacoseira ambigua, A. ambigua f. japonica, and Ulnaria acus in this study. Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray- Curtis similarity identified 4 major groups, which corresponded to microalgae assemblages and their characteristic species. Correlation was analyzed through the CCA analysis. It was found that there was a correlation between the microalgae and environmental factors. It was revealed that the divided groups were distinguished because of the differences by the survey period. Therefore, seasonal change was judged as a major factor affecting the distribution of microalgae communities.

The Distribution Characteristics of Incised Meander River in the Korean Peninsula (한국에 있어서 감입곡류 하천의 분포 특성)

  • 송언근;조화룡
    • The Korean Journal of Quaternary Research
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    • v.3 no.1
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    • pp.17-34
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    • 1989
  • The distribution characteristics of incised meander river are analysed concerning topography, geology, stream order and altitude. Additionally geomorphological development of the Korean peninsular is considered with incised meander. The main findings are as follows: 1. The incised meander is intensively distributed on the west and north slope of T'aebak and Sobaek mountain range, but sparsely distributed on the opposite slopes. 2. Geologically, the occurrence rate of incised meander is high orderly as follows: Joseon supergroup, Pyeongan supergroup, Daedong supergroup metamorphic rock, Gyeongsang supergroup, and granite. The incised meander is developed well on the following conditions: hard rocks against weathering, stratified structure, geologic arrange across the river channel and contacting zone of geological formations. 3. The higher stream orders are, the higher occurrence of incised meander is. 4. Comparing the altitude of present river bed with the summit level of restored map, it is supposed that the incised meander rivers have been dissected about 300-500m down ward. 5. Considering the distribution characteristic of incised meander, it is suggested that not only T'aebak mountain range but Sobaek mountain range is the axis of asymmetrical up-warping in the Korean peninsular. 6. Considering the distribution characteristic of incised meander on the restored map and the stream order, it seems that present incised meander channel was inherited from antecedent meander river that had flowed on High and Middle level erosion surface. But the channel pattern has been modified.

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