• 한국지형학회지
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• 제24권1호
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• pp.13-24
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• 2017

This study analyzes altitude changes of riverbed at 6 bridges in the upper and lower reaches of Yeongju Dam in Naeseong River, from 2009 to 2016 just before and after the dam construction. For 5 years from November 2010 to December 2015 when the dam was under construction, approximately 0.091m of the riverbed altitude in average more than twice before the dam construction was lowered, because of the effects of riverbed excavation for riverside maintenance in the upper reaches and transport limitation of flow and sediment by the dam in the lower reaches. Between November 2009 and December 2016 when the dam was in pre-construction and post-construction stages, respectively, the most sites in this study in the upper and lower reaches showed lowering in the riverbed altitudes. On the other hand, the riverbed around Hoeryongpo closed to the river mouth seems to be influenced by channel changes in Nakdong River rather than by the dam construction.

• 한국측량학회지
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• 제31권6_2호
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• pp.529-538
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• 2013

Coastline is the most dynamic part of seascape since its shape is affected by various factors. Coastal zone is an area with immense geological, geomorphological and ecological interest. Monitoring coastal change is very important for safe navigation, coastal resource management. This paper shows a result of monitoring coastal morphological changes using Remote Sensing and GIS. Study was carried out to obtain intensity of erosion, deposition and sand bar movement in the Red River Delta. Satellite images of ALOS/AVNIR-2 and Landsat were used for the monitoring of coastal morphological changes over the period of 1975 to 2009. Band rationing and threshold technique was used for the coastline extraction. Tidal levels at the time of image acquisition varied from -0.89m to 2.87m. Therefore, coastline from another image at a different tidal level in the same year was considered to get the corrected coastline by interpolation technique. A series of points were generated along the coastal line from 1975 image and were established as reference points to see the change in later periods. The changes were measured in Euclidean distances from these reference points. Positive values represented deposition to the sea and negative values are erosion. The result showed that the Red river delta area expanded to the sea 3500m in Red river mouth, and 2873m in Thai Binh river mouth from 1975 to 2009. The erosion process occurred continuously from 1975 up to now with the average magnitude 23.77m/year from 1975 to 1989 and 7.85m/year from 2001 to 2009 in Giao Thuy area. From 1975 to 2009, total 1095.2ha of settlement area was eroded by sea. On the other hand, land expanded to the sea in 4786.24ha of mangrove and 1673.98ha of aquaculture.

• 한국환경복원기술학회지
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• 제16권3호
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• pp.1-17
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• 2013

This study was conducted to understand the habitat characteristics of Psilotum nudum of Dosuncheon river and Anduck valley in Jeju Island. The total of 79 vascular plants taxa including 39 families, 58 genera, 75 species and 4 varieties were investigated in Dosuncheon river, while 59 vascular plants taxa consisting of 34 families, 50 genera, 53 species and 6 varieties were investigated in Anduck valley. When it comes to the life form, the rates of distribution of annual plants (therophytes) at the mouth of Dosuncheon river and Anduck valley were lower than those of the Korean peninsula and Jeju Island. However, the rates of distribution of chamaephytes and epiphytes were higher at the mouth of Dosuncheon river and Anduck valley. As for vegetation, epiphytes (such as Trachelospermum asiaticum var. intermedium, Trachelospermum asiaticum var. majus and Lemmaphyllum microphyllum) and adiantum plants (including Psilotum nudum, Cytomium fortunei and Rumohra aristata), which are typically easy to be dispersed in rocky zones, dominated these areas since they are vertical or horizontal joints containing wide rocky zones. The main threats to the habitats of Psilotum nudum are environmental pollution, lack of publicity, installation of various facilities such as recreational facilities, gathering for medical and horticulture purposes, vegetation succession and application of waterfront. The management of the rocky zones as habitats for Psilotum nudum is an important factor in their expansion.

• 생태와환경
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• 제40권2호
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• pp.273-284
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• 2007

동물플랑크톤의 공간적 시간적 동태 변화에 대해서 섬진강 중하 류(하구언 댐 무)및 영산강 중 하류(하구언 댐 유)약 100 km구획 내에서 2004년 11월부터 2006년 8월까지 월 간격으로 조사하였다. 두 수계 내 동물플랑크톤 생체량의 공간적 변이는 뚜렷하였다. 영산강 조사 구획 내 총 동물플랑크톤 밀도의 종적 변이는 뚜렷하였다. 강 하류 지역의 하구언 댐으로 향할수록 총 동물플랑크톤 밀도가 증가하였다. 이에 반해 섬진강의 조사 구획 내 총 동물플랑크톤 밀도 변이는 통계적으로 유의하지 않았다. 영산강 구획 내 평균 총 동물플랑크톤 밀도는(평균범위: $199{\sim}817$ 개체수 $L^{-1}$), 3 조사지점, n=20) 섬진강 구획 내 평균 총 동물플랑크톤 밀도(평균범위: $4{\sim}60$개체수 $L^{-1}$, 4 조사지점, n=20)보다 약 $4{\sim}60$ 배 정도 높았다. 영산강 수계(총 동물플랑크톤 밀도의 86% 이상)에서 윤충류의 상대 풍부도는 섬진강 수계에 비해 현저히 높았다. 두 수역에서 우점 한 종은 Polyarthra spp., Brachionus spp., Colurella spp., 및 Keratella spp. 였다. 섬진강 구획 내에서의 요각류의 탄소 생체량은 강 하류로 향할수록 증가하였다(총 동물플랑크톤 탄소 생체량의 40% 이상). 식물플랑크톤에 대한 총 동물플랑크톤 섭식률의 평균 범위는 영산강 구획 내에서는 $21.2{\sim}92.6mL\;L^{-1}\;D^{-1}$이며, 섬진강 구획 내에서는 $2.1{\sim}2.6mL\;L^{-1}\;D^{-1}$의 변동 범위를 보였다. 동물플랑크톤의 섭식률을 고려 해 볼 때, 영산강 구획 내에서 동물플랑크톤에 의한 플랑크톤 먹이환내에서의 역할의 중요성이 섬진강 구획 내에서 보다 상대적으로 높을 것으로 사료된다.

• 한국환경과학회지
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• 제25권1호
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• pp.1-10
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• 2016

Bottom sediment pollution with heavy metals of the Sventoji River in Ukmerge, Lithuania using X-ray fluorescence spectrometry is analyzed in this article. During the research, qualitative and quantitative parameters of heavy metal concentrations and their distribution were investigated. This article presents obtained results of study, where bottom sediment samples were examined from both shores of the river of Sventoji. During this research, received data was treated using GIS software, which helped to interpolate the data of concentrations into the research polygon of the river. GIS software also helped to evaluate the urban runoff influence to the bottom sediment quality and exclude sources of pollution. The runoff dischargers which transport surface wastewater to the river were registered before sampling. At the mouth of streams, flowing into the river of Sventoji, additional samples were taken. After comprehensive river bottom sediment research there is a possibility to assess the extent of anthropogenic activity and its impact on the river ecosystem and human health.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1982년도 제24회 수공학 연구발표회 논문초록집
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• pp.3-24
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• 1982

The relations between tidal fluctuation and freshwater discharge are stuied dy use of observed data in the estuarine region of the Nagdong Rivre. Damping modulus which represents the resistance to propagation of tidal wave is estimated, and it is verified that when the fresh water discharge is lower than 300 m/sec., the elevation of mean-water-level at Gupo is the same as mean sea-water-level.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.488-493
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• 2006

Accurate river discharge is the most important factor in managing river basins and for successfully maintaining total maximum daily loads in Korea. It is not easy to measure the discharge directly in large rivers owing to physical and environmental constraints, even after investing much time and money. Recently, to overcome these historical drawbacks in river discharge measurement, we have developed the Automatic Discharge Acquisition & Management System (ADAMS) that scans the river cross-section and measures each cell $(1m{\times}1m)$ velocity using HADCP. The hardware system is composed of an HADCP sensor and winch, as well as a PC and software system for the discharge calculation module and hardware control module. It is controlled remotely via the internet and uses the velocity-depth integration method and the velocity-contour method for calculating river discharges. The characteristics of ADAMS are a ubiquitously accessible system, featuring real time automatic discharge measurement, remote control via the internet. The results using ADAMS at the Jindong stage site show less than 5% uncertainty and are 4 times more efficient than the ADCP & Q-boat system. This system can be used to measure any large river, river mouth or tributary river affected by backwater, all of which have a very difficult measuring real time discharge. The next generation of ADAMS will feature an upgrade to increase portability and GPS integration.

• 미생물학회지
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• 제29권5호
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• pp.339-343
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• 1991

Heterotrophic activity, total bacteria and salinity were determined seasonally in the estuary of Naktong River over half tidal cycle. Heterotrophic activity was determined by the uptake of [U- $^{14}$ C]glucose. Heterotrophic activity fluctuated with the tides and was decreased as salinity increased. Teh great activity occurred near low ebb tide at all seasons except summer. The main environmental factor affecting hetreotrophic activity was the salinity rather than water temperature in the estuary of Naktong River. In order to estimate the effect of salt, salt was added to estuarine water. Vmax for glucose of salt-added water was 17% and 77% of original estuarine water at station 1 and 2 respectively and slight increase was observed at station 3. Respiration rate and Kt+Sn for glucose of salt-added sample increased at all 3 stations. The increase of the Kt value implies the reduced affinity of bacterial population for glucose. The effects of salinity on the heterotrophic activity were more extensive in the upper region of estuary than at the mouth.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1013-1022
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• 2005

Because depth of deposit is deeper as well as compressibility is very larger than the other regions in Korea, behaviour of settlement at Nak-Dong river estuarine causes hot issue at ground improvement. Defined properties for design differ from measurement. Therefore it affects cost of construction. This study presents design standard to engineers as it defined properties of compressibility at Jangyu Area of Nak-Dong river estuarine. To search value of representation for region, back analysis was performed using the measurement. To verify that, the measurement of recently designed site was confirmed, and the cost of construction with properties of consolidation was calculated.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.257-262
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• 1996

Large amount of water is diverted annually for irrigation along the Yellow River. Owing to the tremendous sediment carried by the river , sediment deposits is an important problem in irrigation and drainage system. The sediment has to be taken out by machines from the irrigation system, otherwise water can not be available in the right place at the right time. In order to improve the sediment desilting efficiency, the sediments that settle in certain sites of a irrigation system must be removed by different desilting machines with special performance and working conditions. Those certain sites include : the diversion canal in the flood plain , the mouth of inlet, settling basin , irrigation and drainage system. In view of removal sediment above, the paper presents the ideas of type selection of desilting machines applied to certain sites. Proposals of making further improvement on performance for some desilting machines are also put forward.