• Title/Summary/Keyword: basin

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Soil Loss Vulnerability Assessment in the Mekong River Basin

  • Thuy, Hoang Thu;Lee, Giha
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.1
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    • pp.37-47
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    • 2017
  • The Mekong River plays an extremely important role in Southeast Asia. Flowing through six countries, including China, Myanmar, Thailand, Laos PDR, Cambodia, and Vietnam, it is a site of great biological and ecological diversity and the habitat of numerous species of fish. It also supports a very large population that lives along the river basin. Therefore, much attention has been focused on the giant Mekong River Basin, particularly, its soil erosion and sedimentation problems. In fact, many methods have been used to calculate and simulate these problems. However, in the case of the Mekong River Basin, the available data is limited because of the extreme size of the area (about $795,000km^2$) and lack of equipment systems in the countries through which the Mekong River flows. In this study, we applied the Universal Soil Loss Equation (USLE) model in a GIS (Geographic Information System) framework to calculate the amount of soil erosion and sediment load during the selected period, from 1951 to 2007. The result points out dangerous areas, such as the Upper Mekong River Basin and 3S Basin (containing the Sekong, Sesan, and Srepok Rivers) that are suffering the serious consequences of soil erosion problems. Moreover, the present model is also useful for supporting river basin management in the implementation of sustainable management practices in the Mekong River Basin and other basins.

Evaluation of water treatment characteristics at the improved circle secondary settling basin (개량 고속원형침전지의 수처리 특성 평가)

  • Jang, Honggyu;Cho, Youngman;Kim, Changwon
    • Journal of Korean Society of Water and Wastewater
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    • v.28 no.5
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    • pp.609-614
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    • 2014
  • Researcher of this study improved conventional circle secondary settling basin, through the way such as extend of inlet pipe length, introduction of device for inducting uniforming of flow, keeping of height of sludge interface. Also, we compared conventional circle settling basin to improved circle settling basin the water treatment efficiency. Result of research, when SVI is average 117, improvement rate of SS and BOD were 51.0%, 37.0% approximately compared to conventional settling basin. And when SVI is average 178, improvement rate of SS and BOD were 22.7%, 36.0% approximately. Also when SVI is average 196, improvement rate of SS and BOD were 24.7%, 30.3% approximately. When it's winter, improvement rate of SS, BOD, COD, TN and TP were 20.6%, 17.9%, 13.9%, 13.5%, 12.4% approximately. Therefore, we can be the judge, this improved settling basin can be used as the final settling basin in the waste water treatment plant.

MOSIM NETWORK FLOW MODELING FOR IMPROVING CRITICAL HABITAT IN PLATTE RIVER BASIN (플랫강 유역의 위험에 처한 서식지 보호를 위한 MODSIM 하천 네트워크 흐름모의)

  • Lee, Jin-Hee;Kim, Kil-Ho;Shim, Myung-Pil
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.2039-2043
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    • 2007
  • Like other major river basin systems in the West of the United States the Platte River Basin are faced with the challenges of allocating more water for plant and animal species. A part of the Central Platte River was designated as critical habitat for the whooping crane in 1978. The water allocation system in the Platte River Basin is dominated by the Prior Appropriation Doctrine, which allocates water according to the priorities based on the date of water use. The Platte River Basin segregated into five subregions for purpose of analysis. 24 years of historic records of monthly flow and all the demands were complied. The simulation of river basin modeling includes physical operation of the system including water allocation by water rights and interstate compact agreements, reservoir operations, and diversion with consumptive use and return flow. MODSIM, a generalized river basin network model, was used for estimating the timing and magnitude of impacts on river flows and diversions associated with water transfers from each region. A total of 20 alternatives were considered, covering transfers from each of the five regions of basin with several options. The result shows that the timing and availability of augmented water at the critical habitat is not only a function of use by junior appropriators, but also of river losses, and timing of return flows.

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Three-dimensional numerical modeling of sediment-induced density currents in a sedimentation basin (3차원 수치모의를 통한 침사지에서의 부유사 밀도류 해석)

  • An, Sang Do;Kim, Gi-Ho;Park, Won Cheol
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.3
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    • pp.383-394
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    • 2013
  • A sedimentation basin is used to remove suspended sediments which can cause abrasive and erosive wear on hydraulic turbines of hydropower plants. This sediment erosion not only decreases efficiency of the turbine but also increases maintenance costs. In this study, the three-dimensional numerical simulations were carried out on the overseas hydropower project. The simulations of flow and suspended sediment concentration were obtained using FLOW-3D computational fluid dynamics code. The simulations provide removal efficiency of a sedimentation basin based on particle sizes. The influence of baffles on the flow field and the removal efficiency of suspended sediments in the sedimentation basin has been investigated. This paper also provides the numerical simulations for sediment-induced density currents that may occur in the sedimentation basin. The simulation results indicate that the formation of density currents decreases the removal efficiency. When a baffle is installed in the sedimentation basin, the baffle provides intensive settling zones resulting in increasing the sediments settling. Thus the enhanced removal efficiency can be achieved by installing the baffle inside the sedimentation basin.

A Study on the Size of Turning Basin for Vessels of Arrival & Departure in the Berths (부두 입출항 선박을 위한 선회수역 크기에 관한 고찰)

  • Kim, Se-Won;Lee, Yoon-Suk;Park, Young-Soo
    • Journal of Fisheries and Marine Sciences Education
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    • v.24 no.6
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    • pp.872-883
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    • 2012
  • Generally the determination of turning basin for vessels of entering & sailing in the berth has been considered in the design standard of harbor construction rules of the port. In this regard, the turning basin has been determined by the max size of entering vessel of the berth/port. But the size of turning basin may considered the ship's maneuvering ability, operator's skillful power, mooring equipments of the berth, arrangement of the fairway and the environment condition of weather & seas around the designated port area. So this paper suggested the optimum size of turning basin after studying the harbour design rules of the advanced marine countries and using by maneuvering simulator for turning basin size and also evaluated the design standard of harbor construction rules and minimum size of turning basin against ship's length at the Gangjung civil/naval port of Jeju Island.

Assessment of Ecosystem services under changing climate in the Bagmati Basin of Nepal

  • Bastola, Shiksha;Seong, Yeon-Jeong;Lee, Sanghyup;Jung, Younghun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.148-148
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    • 2019
  • The 2006 Millennium Ecosystem Assessment (MA) defines ecosystem services (ES) as "the benefits people obtain from ecosystems". Identifying where ES originates, whom it benefits and how it is changing over a period of time is critical in rapidly developing country like Nepal, where the risk of ES loss is high. In the context of various ecosystem services provided by watershed, this study, particularly deals with water yield, Soil loss and Carbon sequestration computation and evaluation in Bagmati Basin of Nepal. As Bagmati Basin incorporates capital city Kathmandu of nepal, land use change is significant over decades and mapping of ES is crucial for sustainable development of Basin in future. In this regard, the objectives of this study are 1) To compute the total and sub-watershed scale water yield of the basin, 2) Computation of soil loss and sediment retention in the basin, and 3) Computation of carbon sequestration in the basin. Integrated Valuation of Environmental Services and Tradeoffs (InVEST), a popular model for ecosystem service assessment based on Budyko hydrological method is used to compute Ecosystem services. The scenario of ES in two periods of time can be referenced for various approaches of prioritization and incorporation of their value into local and regional decision making for management of basin.

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An approach for deformation modulus mechanism of super-high arch dams

  • Wu, Bangbin;Niu, Jingtai;Su, Huaizhi;Yang, Meng;Wu, Zhongru;Cui, Xinbo
    • Structural Engineering and Mechanics
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    • v.69 no.5
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    • pp.557-566
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    • 2019
  • The reservoir basin bedrock produced significant impact on the long-term service safety of super-high arch dams. It was important for accurately identifying geomechanical parameters and its evolution process of reservoir basin bedrock. The deformation modulus mechanism research methods of reservoir basin bedrock deformation modulus for super-high arch dams was carried out by finite element numerical calculation of the reservoir basin bedrock deformation and in-situ monitoring data analysis. The deformation modulus inversion principle of reservoir basin bedrock in a wide range was studied. The convergence criteria for determining the calculation range of reservoir basin of super-high arch dams was put forward. The implementation method was proposed for different layers and zones of reservoir basin bedrock. A practical engineering of a super-high arch dam was taken as the example.

The Analysis of GIS DB for the Evaluation of Turbid Water Considering Spatial Characteristics of River Channel (하천의 공간적 특성을 고려한 탁수평가 GIS DB 분석)

  • Park Jin-Hyeog;Lee Geun-Sang
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.1
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    • pp.19-26
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    • 2006
  • Andong and Imha reservoir adjoins each other, but turbid water shows too much different when it rains. The characteristics of geological rock in basin and agricultural area around river boundary are pointed out as the major reason of turbid water of Imha reservoir. This study analyzed rock type of topsoil layer using soil map by National Institute of Agricultural Science and Technology (NIAST). Among rock types, sedimentary rock affects on the occurrence of turbid water. In the analysis of sedimentary rock type, the distribution of sedimentary rock of Imha basin shows 1.87 times higher than that of Andong basin. Also, the distribution of sedimentary rock of Imha basin shows higher than that of Andong basin within 1,600m from river channel in according to the buffer zone of river boundary. And Agricultural area of Imha basin shows higher than that of Andong basin in analysis of land cover within 1,600 m from river channel. As this agricultural characteristics of Imha basin, cover management factor of Imha basin represents more higher that that of Andong basin.

INTEGRATED WATER RESOURCES AND QUALITY MANAGEMENT SYSTEM USING GIS/RS TECHNOLOGIES

  • Shim, Kyu-Cheoul;Shim, Soon-Bo;Lee, Yo-Sang
    • Water Engineering Research
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    • v.3 no.2
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    • pp.85-92
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    • 2002
  • There has been continuous efforts to manage water resources for the required water quality criterion at river channel in Korea. However, we could obtain the partial improvement only for the point sources such as, waste waters from urban and factory site through the water quality management. Therefore, it is strongly needed that the best management practice throughout the river basin fur water quality management including non-point sources pollutant loads. This problem should be resolved by recognizing the non-point sources pollutant loads from the upstream river basin to the outlet of the basin depends on the landuse and soil type characteristics of the river basin using the computer simulation by a distributed model based on the detailed investigation and application of Geographic Information System (GIS). The purpose of this study is consisted of the three major distributions, which are the investigation of spread non-point sources pollutants throughout the river basin, development of the base maps to represent and interpret the input and outputs of the distributed simulation model, and prediction of non-point sources pollutant loads at the outlet of a up-stream river basin using Agricultural Non-Point Sources Model (AGNPS). For the validation purpose, the Seom-Jin River basin was selected with two flood events in 1998. The results of this application showed that the use of combined a distributed model and an application of GIS was very effective fur the best water resources and quality management practice throughout the river basin

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Geomorphological Environment of Daejeon Basin and Its Influence Urbanization (지형을 중심으로 한 대전 지역의 이해)

  • Kee, Keun-Doh;Lee, Min-Ho
    • Journal of the Korean association of regional geographers
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    • v.8 no.2
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    • pp.229-246
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    • 2002
  • This study is a contribution to the geographical understanding of Daejeon Area, playing the role of principal center of Choongchong Province. This area has been urbanized associated with Daejeon Basin, an important natural unit in the middle part of South Korea. In order to understand Daejeon Area in geographer's view, it is necessary to elucidate geomorphological environment of Daejeon Basin and urban expansion pattern associating with it. Our research is converged into dual objectives: one, description and interpretation of basin's landforms; other, urban expansion relating with geomorphological condition. Daejeon's urban expansion has progressed from the border zone of Daejeon Basin toward into the basin, and then vice versa. Relating to rivers valleys in the basin, the urbanization in the basin has been extended from the river valleys of lower order toward those of higher order. Understanding of the geomorphological mosaique of Daejeon basin is an important base for that of urban mosaique of Daejeon City.

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