• Title/Summary/Keyword: 토사퇴적

Search Result 219, Processing Time 0.03 seconds

Significance of Biomarkers in the Assessment of Dredged Materials for Beneficial Reuses and Disposal (준설물질 유효활용 및 처분을 위한 평가에 있어 생체지표 활용의 재고)

  • Won, Eun-Ji;Choi, Jin Young;Kim, Kyoungrean
    • Journal of Environmental Impact Assessment
    • /
    • v.25 no.6
    • /
    • pp.466-476
    • /
    • 2016
  • Dredging is inevitably necessary for the management of water infrastructure such as waterways and polluted bottom sediment. Dredged material management options may be offshore dumping, wetland creation, beach nourishment and various other engineering uses depending on the given circumstances at the time of dredging. Among those options, wetland creation and beach nourishment are the preferred ones in Korea considering significant loss of wetland and beach erosion due to various development projects along the coastal region. In order to use dredged material beneficially, however, dredged material needs to be assessed its suitability with respect to its engineering purpose and environmental criteria. In this paper, we demonstrate that environmental risk of dredged material to be introduced into the marine environment can be easily assessed using biomarkers with relative low cost. Biomarkers can also compliment pollutant contents analysis that may not be specific to their impact on biological response. Biomarker information may be used to assist decision making process in selecting suitable treatment or beneficial use options for dredged materials.

The Irrigation and Drainage Systems of Coastal Alluvial Plain: Sand Dune Area and Allurial Plain in Bulgap River Catchment in South Jeolla Province (소규모 임해충적평야의 수리체계 -불갑천 하류의 충적지와 해안사구를 중심으로-)

  • Kahng Taygyoon
    • Journal of the Korean Geographical Society
    • /
    • v.39 no.6 s.105
    • /
    • pp.863-872
    • /
    • 2004
  • The coastal alluvial plain, sand dune, tidal nat might be the most prominent coastal landscape in western coast of Korea. The purpose of this paper is to examine the irrigation and drainage systems of the alluvial plain in the tidal coast. This study is concerned on the geomorphological and cultural landscapes of the alluvial plain in the western coast of the South Jeolla Province. The alluvial deposits have developed mainly by the actions of tidal currents, rather than transporting sediments by stream. The transformation of plain has been affected by human agency since 1920's. Dwellers have constructed the reservoir, banks, dammed pools, lock gates, and tide-dykes for the reclamation, irrigation, and drainage on the alluvial plain, coastal sanddune, and tidal flats.

Study on Characteristics for Local Deposit of Sediment by Surveying River Bed's Layer History in High Berm of River Channel (하도 층구조 이력조사를 통한 하도내 국지퇴적 특성 분석)

  • Ryu, Young-Hoon;Lee, Sam-Hee;Ahn, Won-Sik
    • Journal of Korea Water Resources Association
    • /
    • v.43 no.10
    • /
    • pp.883-891
    • /
    • 2010
  • More recently, there have been significant changes in the forms of channels due to runoff characteristics driven by climate changes and other alterations in basin/channel environments. Particularly, increasing local deposition in major channels is being observed nationwide. Of such phenomena, it is noteworthy that flood-plains show unidirectional growth and lowering of channels within compound channels in the form of a high-flow plain. These changes are supposed to affect management of the river ecology as well as flood control. In this study, the research on channels in Korea confirmed that the phenomenon of local deposition in those channels is actually taking place, rendering a problem to be urgently addressed. Previous studies on bed changes have been focused on low channels based on bed materials distributed over the channels. However, this research has proved that surface-layer deposition of a high-flow plain is closely related with changes in the conditions of ground surfaces and, ultimately, affects the bed of the entire channel as well. According to the intensive research on the condition of the high-flow plain of the mouth of the Han River, the silt deposited in the high-flow plain was the main cause of settlement/growth of vegetation. And this leads to landforming along with woods-forming, disturbing flood control as well as the normal river ecology.

Topographical Changes in Torrential Stream After Dredging in Erosion Control Dam - Using Terrestrial LiDAR Data - (사방댐 준설이 계류의 지형변화에 미치는 영향 - 지상 LiDAR 자료를 이용하여 -)

  • Seo, Junpyo;Woo, Choongshik;Lee, Changwoo;Kim, Kyongha;Lee, HeonHo
    • Journal of Korean Society of Forest Science
    • /
    • v.103 no.3
    • /
    • pp.392-401
    • /
    • 2014
  • This research was carried out to understand the impact of mountainous torrent on topographical change of slope and sediment volume within a deposit line by dredging of soil erosion control dam. Terrestrial LiDAR surveys were conducted at dredged and non-dredged sites. Terrestrial LiDAR has an advantage on detecting topographical changes easily without demanding workmanship and technical skill for users. The distribution of erodible slope ($20^{\circ}-40^{\circ}$) was higher in non-dredged site than that of dredged site. However, the distribution was higher in dredged site than that of non-dredged site after rainy season. Erosion and deposition appeared regularly in a dredged site, but those occurred irregularly in the non-dredged site. The inflow of soil per square meter was 1.7 times higher in dredged site than that of non-dredged site after rainy season. The difference of rainfall in each site did not affect to soil erosion. The distribution of erodible slope was increased in dredged site than that of non-dredged site after rainy season due to inflow of soil from upper stream caused by dredging.

Soil Physical and Chemical Characteristics of River-Bed Sediments in River Basins (하천 퇴적토양의 이화학적 특성)

  • Zhang, Yong-Seon;Sonn, Yeon-Gye;Park, Chan-Won;Hyun, Byung-Keun;Moon, Yong-Hee;Song, Kwan-Cheol
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.44 no.6
    • /
    • pp.963-969
    • /
    • 2011
  • The river-bed sediments from the major river basins were analysed for the chemical and physical properties to evaluate environmental safety for the agricultural uses. The samples were taken from 16 sites of Han river, 36 of Geumgang river, 27 of Yeongsan river, and 140 of Nakdong river. The total of 219 samples from the 28 counties were taken from the surface of the sediments at the depth of 50 cm. The particle density of the sediments was greater than $2.63Mg\;m^{-3}$ and the whole range of the density was $2.60{\sim}2.69Mg\;m^{-3}$, the average particle size was 0.7 mm whereas the size range was 0.075~0.85 mm. The analyses of the particle sizes by basins showed that Han and Geumgang river had particle sizes of 0.075~0.85 mm, while Geumgang and Yeongsan river had particle sizes of 0.25~0.85 mm. Geumgang and Yeongsan river tended to have greater particle sizes. The average values of the chemical properties were 6.3 for pH, $0.16dS\;m^{-1}$ for EC, $8g\;kg^{-1}$ for organic matter, $101mg\;kg^{-1}$ for available phosphate, 0.39, 3.47, and $0.93cmol_c\;kg^{-1}$ for exchangeable potassium, calcium, and magnesium respectively. The greatest property at each basin was pH for Han river, Ec, available phosphate and exchangeable sodium for Geumgang river, organic matter, exchangeable calcium and magnesium for Yeongsan river, and exchangeable potassium for Nakdong river.

Potential damage assessment of inland wetlands by topsoil erosion (표토침식에 따른 내륙습지 훼손 가능성 평가)

  • Kim, Seongwon;Jeong, Anchul;Lee, Daeeop;Lee, Giha
    • Journal of Korea Water Resources Association
    • /
    • v.53 no.7
    • /
    • pp.521-531
    • /
    • 2020
  • The purpose of this study is to suggest a quantitative assessment of wetland damage considering the effects of topsoil erosion and deposition from rainfall. In the Cheoncheon Basin located upstream of the Yongdam Dam, 16 wetlands are located, but the lacustrine and small palustrine wetland were analyzed for possible damage to erosion and deposition. As a result of applying typhoon events in 2002 and 2003, the sediment load from the upper basin was the highest at 2.30% (22,548 ㎥) of low water capacity. The average sediment load in the mountain areas was found to be 0.03% of the low water capacity, and it was analyzed to be less damaging than the lacustrine with relatively large watershed. as a result of the model, the lacustrine wetland, where a large area is used as agricultural land, shows a high probability of sediment yield, so it is highly likely to damage the wetland by topsoil erosion.

Effective Water Resources Development by the Management of Sediment Deposit in Agricultural Reservoirs (농업용 저수지의 퇴적토사 관리를 통한 효율적 수자원 개발)

  • Son, Kwang-Ik;Shim, Myung-Pil
    • Journal of Korea Water Resources Association
    • /
    • v.37 no.6
    • /
    • pp.467-477
    • /
    • 2004
  • Effective management of water resources in Korea becomes very important in recent years. Especially, the management of reservoirs cannot be over emphasized. The status of sediment deposit and the dredging records of agricultural reservoirs were examined to find out at e reservoir retention capacity could be raised more than 10% of the total volume of reservoirs in Kyungbook Province. Sediment prediction methods were developed by combining the estimation mothods of geomorphological characteristics and upslope contribution area in GIS, The estimated sediment depsit amount were compared with the dredging records for three agricultural reservoires. It was found that the distributed model with ‘Flow accumulation’ and ‘Multiple Flow Direction Algorithm’ gives good prediction results for mountaineous area.

A Study on the Bed Load Collision Sound Analysis Using Sound Sensor and Denoising Filter (음향센서와 디노이징 필터를 활용한 향상된 소류사 충돌음 분석 연구)

  • Kim, Sung Uk;Jun, Kye Won
    • Journal of Korean Society of Disaster and Security
    • /
    • v.14 no.2
    • /
    • pp.43-50
    • /
    • 2021
  • In Korea, the frequency of soil disasters has soared recently due to increased torrential rains caused by abnormal weather conditions. In particular, soil generated from mountainous areas is flowing into small rivers along valleys, depositing rivers and adding to flood damage. In order to prevent damage from such soil disasters, it is important to predict sediments and to quantitatively identify bed load. In this work, we conducted an experiment to indirectly measure acoustic sensor-based bed load collision sounds using pipe hydrophones, and compared them with raw data by applying denoising methods to improve the reliability of the measured data. As a result, we derive results in a more clear analysis of bed load estimation by correcting noise when the denoising method is applied to raw data.

Effects of Grain Size on Relationship between Microtopographic Roughness and Soil Erosion Rate (토양 입경이 미세지형의 거칠기와 토양침식률 간의 관계에 미치는 영향)

  • Soyoung Kim;Dae-Hong Kim;Tae-young Sohn
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2023.05a
    • /
    • pp.216-216
    • /
    • 2023
  • 가속적인 토양침식은 토지의 환경 및 생태계의 지속성에 부정적 영향을 미치므로, 그 양을 예측하여 토양침식을 방지하는 것은 중요하다. 이에 따라 식생, 지형, 토양의 입도분포 등과 같은 토양침식에 영향을 미치는 인자에 관한 연구가 꾸준히 이뤄지고 있다. 특히 자연 지형에서 보편적으로 나타나는 'cm' 규모의 미세지형이 토양침식에 미치는 영향을 분석한 기존 연구 결과를 살펴보면, 유역 출구 지점에서 관측된 총 유사유출량에만 근거하고 있을 뿐 아니라 토양침식에 미치는 미세지형의 영향에 관한 상반된 결과가 혼재하고 있다. 이는 유역의 토양침식과정에 대한 이해도와 토양침식량에 대한 예측 정확도를 저하시킬 우려가 있으므로 미세지형이 토양침식에 미치는 영향을 유역 전반에 걸쳐 살펴본 후, 명확하게 하는 것이 필요하다. 본 연구에서는 동역학파 모형에 기반한 침식 모형을 이용하여 미세지형에서의 강우-유출 및 토사 입자별 침식 및 유출 현상을 수치적으로 모의하였다. 모의 결과에 따르면, 동일한 강우-유출 조건에서도 미세지형의 거칠기에 따라 유역의 토양침식량 및 침식 특성이 달라질 수 있으며, 토양 입경이 미세지형의 거칠기에 따른 유사유출량의 증감 현상을 결정하는 데에 있어 중요한 요소로 작용함을 제시하였다. 미세지형이 거칠어짐에 따라 비교적 굵은 입자인 모래 함량이 높은 지반에서는 토양침식률이 감소하였으나 이와 대조적으로 미세토사 함량이 높은 지반에서는 토양침식률이 증가하였다. 이는 미세지형이 유역 전반에 걸쳐 입경에 따른 토사의 부상, 이류 및 퇴적 특성에 영향을 미쳐, 유역의 유사 분급 및 장갑화 현상에 깊게 관여하였기 때문이다. 본 연구를 통해 토양유실에 미치는 미세지형의 영향에 관한 상반된 연구 결과를 미세지형과 토양 입경분포의 상호작용으로 설명할 수 있다. 따라서, 본 연구는 유역 내 미세지형적 거칠기 입경분포에 대한 정확한 정보에 기반하여 토양의 유실량 및 침식량을 산정해야 함을 강조한다.

  • PDF

Sediment Transport Characteristics in a Pressure Pipeline (압력 원형관로내 유사이송특성 연구)

  • Son, Kwang Ik;Kim, Hyun Jung
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.31 no.3B
    • /
    • pp.205-209
    • /
    • 2011
  • The low carrying capacity caused by the deposition in a sewer line is one of the main reason of the urban flood. Therefore, an efficient maintenance and management of the storm water drainage system is very important to prevent urban flood. In this research, the sediment transport characteristics through a pressure pipeline were examined with laboratory experiments. Bed-forms in a pipeline, sediment rates, roughness due to sediments were examined. Experimental system consists of flow circulation system with a pump and a sediment feeder at the upstream of the pipeline. Sediments were supplied into a 60 mm-diameter and 8 m-long pipe. Maximum flow rate is $30m^3/hr$, and the sediment feeding rate range is 5 g/s~19 g/s. Governing parameters and estimation equation for sediment transport rate were developed. The mean velocity (U), coefficient of viscosity (${\mu}$), unit width bed load ($q_b$), mean diameter of particle ($d_{50}$), unit weight of sediment in water (${\gamma}^{\prime}_s$) were adopted as the most influencing factors of sediment transport patterns. The prediction equation for sediment transport rate were developed with two dimensionless terms. These two dimensionless terms showed a linear relationship with high correlation coefficient.