• 디지털융복합연구
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• 제16권7호
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• pp.47-54
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• 2018

최근 우리나라는 토사재해로 인하여 해마다 많은 인명과 재산피해가 발생하고 있다. 비교법적으로 검토해 보면, 일본 히로시마에서는 1999년에 폭우로 인한 토사재해로 엄청난 피해가 발생하였는데, 이후 제정된 토사재해방지법에 근거하여 도도부현에 토사 재해 방지를 위한 비 구조 대책이 도입되었다. 여기에는 토사재해 경보, 대피 표준 강우량 제정, 토사재해 경계 구역 지정 및 토사재해 특별 경계 구역 지정 등이 포함되어 있다. 또한 구체적인 실제 적용례로서, 일본 가고시마현의 토사재해경계정보시스템과 전문 인력 활용방안인 일본 국토교통성의 TEC-FORCE사례를 중점적으로 살펴보았다. 향후, 일본과 같은 토사재해경계시스템과 전문 인력을 활용한 피해예방 및 피해저감 대책이 절대적으로 필요하다고 할 것이다.

• Ecology and Resilient Infrastructure
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• 제2권3호
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• pp.247-254
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• 2015

Changes in land-use type can affect soil and water properties in stream ecosystems. This study examined the effects of different land-use types on biogeochemical properties and microbial activities of a stream. We collected water and sediment samples in a stream at three different sites surrounded by varying land-use types; a forest, a radish field and a rice paddy. Nitrogen contents, such as nitrate, nitrite and total nitrogen in the stream water body, showed significant differences among the sampling sites. The highest nitrogen values were recorded at the site surrounded by cropland, as fertilizer runoff impacted the stream. Soil organic matter content in the sediment showed significant differences among sites, with the highest content exhibited at the forest mouth site. These differences might be due to the organic matter in surrounding terrestrial ecosystems. Microbial activities determined by extracellular enzyme activities showed similar values throughout all sites in the water body; however, the activities in the sediments exhibited the highest values near the forest site and mirrored the soil organic matter content values. From these results, we conclude that different land-use types are important factors affecting water and sediment properties in stream ecosystems.

• 한국지구과학회지
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• 제23권8호
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• pp.707-721
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• 2002

사이드 스캔 소-나 시스템을 이용하여 태안반도 부근 신두리 해역에서 해저면 음향영상 자료를 획득하였다. 후방산란 음향강도와 해저퇴적물의 물성에 대한 상호관계를 연구하였다. 그리고 위의 두 자료 모두 해저수심과 각각 비교해석 하였다. 해저퇴적물의 물성 대부분은 음향강도와 좋은 상관관계를 보이고 있지만, 퇴적물의 분포양상은 암반노출지역을 제외하고는 해저면 음향영상과 정확하게 일치하지는 않았다. 해저수심은 해저면 음향영상의 분포형태에 영향을 미치고 있었을 뿐만 아니라, 해저퇴적물의 물성 분포에서도 선형적인 관계를 보이고 있었다.

• 한국농공학회지
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• 제40권4호
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• pp.85-93
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• 1998

In the 2nd year study of a 5 year project to evaluate the soil quality and develop the best management practices for mountaineous soils, 11 runoff plots were treated and monitored with respect to physical property of the soil, runoff and sediment discharge, and the following results were obtained. 1. Bulk density and porosity did not show any siginificant difference between experimental treatments. 2. Runoff was basically dependent on the soil's physical property and tillage. Up-and-down plots showed the highest runoff while contour plots the lowest runoff. 3. Sediment yield in the mountaineous soils was directly related to tillage and residue cover. Residue covered plots showed the lowest sediment yield and up-and-down plots the highest sediment yield. And it is recommended that the best management practices using till_age and residue cover for the mountaineous soils must be developed to protect soil quality and maintain agricultural productivity.

• The Journal of the Acoustical Society of Korea
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• 제25권1E호
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• pp.1-7
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• 2006

This study examines the reflection characteristic of a thin transition layer of the ocean bottom showing variability with respect to depth. In order to model the surficial sediment simply, we reduce the Biot model to the depth dependent wave equation for the pseudo fluid using the fluid approximation (weak frame approximation). From the reduced equation, the difference between the inherent frequency dependency of the reflection and the frequency dependency resulting from a thin transition layer is investigated. Using Tang's depth porosity profile model of the surficial sediment [D. Tang et al., IEEE J. Oceanic Eng., vol.27(3), 546-560(2002)], we numerically simulated the reflection loss and investigated the contribution from both frequency dependencies. In addition, the effects of different sediment type and varying depth structure of the sediment are discussed.

• 한국습지학회지
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• 제10권3호
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• pp.9-26
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• 2008

순천만에서 갈대군락이 저토의 이화학적 특성에 미치는 영향과 갈대군락의 증가형태를 파악하기 위해 1999년과 2000년에 갈대군락의 폭을 측정하고 2007년에 갈대군락의 형성정도에 따라 3개 지역을 선정하여 깊이별 저토의 수분함량, 염분농도, 유기물함량, 황함량, 질소함량, 탄소함량 및 수소함량을 조사하였다. 갈대군락의 유무와 관계없이 육지와 멀리 격리되어 있을수록, 수로와 가까이 있을수록 저토 내 수분함량이 많고 염분도가 높았다. 또한 표층의 유기물함량은 갈대의 현존량과 비례하였지만 하층의 것은 오래된 갈대군락에서 오히려 낮았다. 황함량은 나지(0.23%)나 근래에 형성된 갈대군락(0.21%)보다 오래된 갈대군락(0.33%)에서 높았고, 탄소, 질소 및 수소의 함량은 표층에서 현저히 높고 하층에서 낮아 대체로는 유기물함량과 유사한 경향성을 보였지만 하층으로 감에 따라 감소하거나 증가하는 경향은 일치하지 않았다. 갈대군락 폭의 증가는 1999년에 $2.33{\pm}0.73m$, 2000년에 $3.65{\pm}1.64m$이었으며 연도에 따라, 군락에 따라, 방향에 따라 다양하여 일정한 경향성이 없었다. 이러한 갈대군락의 증가 특성에 의해 시간의 경과에 따라 전체적으로 원형의 군락을 이루는 것으로 생각되었다. 매해 증가한 지역에서 갈대의 밀도와 초장은 가장자리로 갈수록 감소하였다. 또한 하나의 군락에서 밀도는 방향(육지 혹은 해양)에 따른 경향성은 없었으나 초장은 북쪽 혹은 육지방향이 남쪽 혹은 해양방향보다 작은 것으로 나타났다.

• 한국해양학회지
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• 제22권1호
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• pp.25-33
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• 1987

河口와 인접한 內 에서 海流에 의한 微細粒 堆積物質의 輸送, 擴散現象을 數値的으로 分析하였다. 사용된 모델은 水理實驗과 現場觀測의 최근 硏究結果를 근거로 開發되었으며 堆積物의 浮上, 堆積, 輸送過程을 보다 실제 상황에 근접하도 록 數値, 計算하였다. 江의 흐름과 潮汐에 의한 海水流動, 이에 따른 沿岸海域에서의 浮遊物質 濃度, 海底寢食 그리고 堆積分布에 대한 時間別 變化를 計算하였다. 初期 에는 浮上된 堆積物에 의해 浮遊物質의 濃度가 크게 增加되었으나, 時間이 경과됨 에 따라 外海로 輸送되어 江河口에서는 濃度가 크게 줄어들었다. 河口隣接 內 의 海底 堆積物의 寢食과 堆積狀態는 內 의 地形的 條件에 따른 海流의 流速分布와 堆積物 特性에 의해 주로 決定됨을 나타내었다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권2호
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• pp.277-286
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• 2013

Cross-shore sediment transport is very important factor in the design of coastal structures, and the beach profile is mainly affected by a number of parameters, such as wave height and period, beach slope, and the material properties of the bed. In this study cross-shore sediment movement was investigated using a physical model and various offshore bar geometric parameters were determined by the resultant erosion profile. The experiments on cross- shore sediment transport carried out in a laboratory wave channel for initial base slopes of 1/8, 1/10 and 1/15. Using the regular waves with different deep-water wave steepness generated by a pedal-type wave generator, the geometrical of sediment transport rate and considerable characteristics of beach profiles under storm conditions and bar parameters affecting on-off shore sediment transport are investigated for the beach materials with the medium diameter of $d_{50}$=0.25, 0.32, 0.45, 0.62 and 0.80 mm. Non-dimensional equations were obtained by using linear and non-linear regression methods through the experimental data and were compared with previously developed equations in the literature. The results have shown that the experimental data fitted well to the proposed equations with respect to the previously developed equations.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권1호
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• pp.60-70
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• 2022

We evaluated the performance of in-situ capping to prevent the release of phenol, one of hazardous chemicals of concern for their impact on sediment. Sediment near the estuary of Hyeongsan River, Korea, and commercially-available sand were collected to evaluate their physical properties and phenol sorption characteristics. Biodegradation kinetics of phenol spiked into the sediment was evaluated under freshwater and estuarine salinity conditions. These experimental measurements were parameterized and used as input parameters for executing CapSim, a software predicting the performance of in-situ capping. The CapSim simulation demonstrated that capping with 50-cm sand reduced the phenol release by several orders of magnitude over 0.25- and 1-year duration for almost all simulation scenarios. The variables tested, i.e., cap thickness, pore-water movement, and biodegradation rate, showed high correlation to each other to influence the extent of phenol release from sediment to the water column. The findings and the framework employed to evaluate the performance of in-situ capping in this study can be adopted to determine whether in-situ capping is appropriate remedial approach at sediment sites impacted by hazardous chemicals due to accidental spills.

• Computers and Concrete
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• 제8권6호
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• pp.617-629
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• 2011

In this investigation, reservoir sediment and municipal sewage sludge were sintered to form the artificial lightweight aggregates. The sintered aggregates were compared with the commercialized lightweight aggregates to in terms of potential alkali-silica reactivity and chemical stability based on analyses of their physical and chemical properties, leaching of heavy metal, alkali-silica reactivity, crystal phase species and microstructure. Experimental results demonstrated that the degree of sintering of an aggregate affected the chemical resistance more strongly than did its chemical composition. According to ASTM C289-94, all potential alkali-silica reactivity of artificial lightweight aggregates were in the harmless zone, while the potential reactivity of artificial lightweight aggregates made from reservoir sediment and municipal sewage sludge were much lower than those of traditional lightweight aggregates.