초록 ▼

○ 하구 울타리섬 시스템의 퇴적작용은 밀물시 유입구를 통하여 퇴적물이 유입되어 북 또는 북서쪽으로 이동하여 낮은 에너지 조건에서 갯벌과 하구둑 부근 수로 근처에 퇴적되며, 썰물시 하구둑에서 유출된 부유 퇴적물은 많은 양이 유입구를 통하여 유출
○ 14개의 소환경의 환경요인을 다변량분석한 결과, 6개 소환경으로 나누어지며, 혼합환경과 해양환경그룹에 속함
○ 유기 지화학 지표 특성 파악결과 신자도, 진우도 북쪽 육지방향에서는 저서미세조류 기여도로 보이며, 울타리섬 남쪽 방향은 육성과 해성의 혼합으로 판단됨
○ 하구역은

○ 하구 울타리섬 시스템의 퇴적작용은 밀물시 유입구를 통하여 퇴적물이 유입되어 북 또는 북서쪽으로 이동하여 낮은 에너지 조건에서 갯벌과 하구둑 부근 수로 근처에 퇴적되며, 썰물시 하구둑에서 유출된 부유 퇴적물은 많은 양이 유입구를 통하여 유출
○ 14개의 소환경의 환경요인을 다변량분석한 결과, 6개 소환경으로 나누어지며, 혼합환경과 해양환경그룹에 속함
○ 유기 지화학 지표 특성 파악결과 신자도, 진우도 북쪽 육지방향에서는 저서미세조류 기여도로 보이며, 울타리섬 남쪽 방향은 육성과 해성의 혼합으로 판단됨
○ 하구역은 세립질 입자의 퇴적률이 낮아 중금속 축적 수준은 낮음
○ 식물 및 동물플랑크톤 군집은 3개의 그룹(담수역, 기수역, 해수역)으로 구분되었고 시기에 따라 해수역과 기수역의 변화가 특징적임
○ 저서생물 특성은 을숙도에서 표층퇴적물식자의 비중이 높았고, 진우도와 신자도에서는 육식자의 비중이 높게 나타났음
○ 낙동강 하구역의 울타리섬은 파랑, 조석, 인위적 공사 등으로 인하여 지형적 변화를 보이고 있음
○ 낙동 델타 퇴적층서는 마지막 빙기이후 해수면 상승과정 동안 하천 환경의 저해수면 퇴적체, 염하구 퇴적환경의 해침퇴적체, 그리고 낙동 델타 퇴적환경의 고해수준 퇴적체가 시퀜스 경계면 위로 차례로 나타남

(출처 : 초록 5p)

Abstract ▼

Ⅳ. Results
The Nakdong River Estuary has been characterized as barrier-lagoon system with various subenvironments. The surface sediments generally showed sand sediment was dominated in the seaward side of barrier islands and muddy sand sediment was dominated on the lagoon. The short-term sediment

Ⅳ. Results
The Nakdong River Estuary has been characterized as barrier-lagoon system with various subenvironments. The surface sediments generally showed sand sediment was dominated in the seaward side of barrier islands and muddy sand sediment was dominated on the lagoon. The short-term sedimentation rates from May 2015 to May 2016 were obtained that the deposition was dominated on the tidal flat between mainland and Jinudo (JW- Line) and Sinjado (SJ-Line) with the net deposition rate of 10.09 mm/year and 12.38 mm/year, respectively. The erosion was dominated on the tidal flats at Eulsukdo (ES-Line), located on the east side of the system, with an annual erosion rate of –12.76 mm/year. Four 12.5-hours anchoring surveys at inlets and channel were revealed that net suspended sediments were transported to the open sea during a tidal cycle in summer 2015, 2016 and 2017. The sedimentary processes of the anthropogenically altered barrier-lagoon system in Nakdong estuary showed that sediments transported into the lagoon through inlets during flood condition and moved to westward and/or northwestward and deposited sediments on the tidal flat and channels near dams in low energy environments. In the east side of the system, sediments flowed out the sea with discharge from Nakdong Dam during ebb condition.

The NRE environment was divided into a total of 14 a priori groups based on landscape factors (i.e., topography, sediment texture, waves, water immersion, vegetation, and biological activity). Based on the analysis of surface sediments collected from 30 sampling stations in these 14 a priori groups, the study area was divided into mixed environments influenced by land and fenced island environments influenced by ocean. This indicates that the NRE is controlled by hydraulic energy and topographical factors. In the CA, six subenvironments were classified into Sub-1 and Sub-2, and the remaining Sub-3, Sub-4, Sub-5, and Sub-6 belonged to the marine environment. A total of six PCs were identified by PCA. Fine sediments, organic matter, and coarse sediments were the major components.

The concentrations of PAHs and PCBs in surface sediments revealed different spatial patterns for these compounds, suggesting that they partially originated from the combustion of fossil fuels and the use of commercial PCB products at adjacent industrial complexes. The PAHs and PCBs in Nakdong River Estuary (NRE) sediments were likely to have originated from the combustion of fossil fuels and biomass at the adjacent industrial complexes. The relative low C/N ratios (average 5.88) imply that the deposited organic matter originated from autochthonous algae derived-sources. The δ¹³C_TOC ranged from –28.2 to –16.8‰_VPDB (average –22.5‰_VPDB), with δ¹⁵N_TN in the range 6.2 – 12.5‰_AIR (average 9.4‰_AIR). Two halophytes (Phragmites communis and Scirpus planiculmis) had δ¹³C_TOC values that ranged from–29.0 to –25.3‰_VPDB (average –26.5‰_VPDB) at ES-R and ES-5. The isotope and elemental composition of sedimentary organic matter (δ¹³C_TOC and δ¹⁵N_TN) indicated the deposition of algae-derived organic matter with limited input from terrestrial organic matter. These results suggest that the microphytobenthos contribution was greater than the inflow of surrounding land vegetation and sediments to the north of the barrier islands had a marine origin. To the south, the effect was considered mixed.

Sedimentation environments in the NRE were classified in to three, 1) fine-grain sedimentation in Eulsukdo tidal flat, 2) high energy environment around Shinjado and Jangjado, and 3) sandy facies with well sorted around Jinudo. In Eulsukdo tidal flat, heavy metals (Cr, Cu, Ni, Pb) became polluted since 1960s, and getting worse during 1990s after construction of the Nakdong Dam. Sedimentation rates on average were 2.5 and 1 cm/yr at Eulsukdo tidal flat and around Shinjado, respectively. Especially, the sedimentation rate decreased to be around 1 cm/yr in Eulsukdo tidal flat after construction of the Nakdong Dam, together with increase in sediment flux of excess metal contents.

The spatial distribution of phytoplankton and zooplankton were identified before and after the flood season in the Nakdong River Estuary. Prior to the flood season, a variety of phytoplankton communities such as diatoms, algae and green algae appeared, while simple community of diatoms appeared after the flood. Prior to the flood season, cladoceran taxa of zooplankton were dominant, while coastal species of Noctiluca scintillans and foraminiferans dominated after the flood.

The communities of phytoplankton and zooplankton were divided into 3 groups(freshwater, estuarine, seawater) during 2016-2017 studies, and changes of the estuarine and seawater groups depended on the study periods. In 2016, Heterosigma akashiwo and Noctiluca scintillans dominated before flood season(May), and Cryptomonas spp. and barnacle larvae dominated after the flood season(September). In 2017, diatoms and Noctiluca scintillans dominated in seawater before(May) the opening of Nakdong River floodgates, whereas, freshwater diatoms and freshwater cladocerans(Daphnia cuculata, D. hyalina) dominated at freshwater immediately after(June), and cyanobacteria and freshwater cladocerans dominated at freshwater after 42 days(July).

The sand contents in the subtidal area decreased from 2015 to 2017, and increase of mud content around the Nakdong River downstream appeared, and its distribution range extends to the south of the barrier island. Opportunistic species were found at the inner area of the Nakdong River dike

The tidal flat benthic community showed the highest proportion in carnivores among feeding types on two tidal flats such as Jinwoo-do and Shinja-do tidal flat. The surface deposit feeders including tube-builders were a dominant functional group in the Eulsuk-do tidal flat, and they might contribute to the sediment stabilization through the tube-building activities. This sediment stabilization may induce the settlement of finer particles and resulted in the increase of mud content at that tidal flat.

The most active region in terms of topographic changes was the recurved spit area of Doyo-deung in the Nakdong River Estuary. Some of the most noticeable topographic changes were seen in Doyo deung under the influence of Typhoon Chaba, which had the largest impact on Busan in October 2016. The width of middle part of Doyo-deoung was increased by 46 m due to overwash, and the recurved spit of the western part had a shoreline retreat about 113 m during the survey period. As a result of coastline change survey by drone photogrammetry, it was observed that the beach ridge was newly formed while the coastline retreated west of Doyo-deung in the recurved spit area. In Doyo-deung, the mean grain size of surficial sediments ranged from 1.87 to 3.25 phi with no seasonal variation. However, after a typhoon, the mean grain size of surficial sediments on shoreline became significantly coarser. Afterwards, the berm crest has recovered with regular wave energy, indicating a grain size trend that sediments moved towards the berm crest. Meanwhile, hydrodynamic condition in surrounding channels is an important steering mechanism in the geomorphology of Doyo-deung. Current speed during ebb tide was 2 times faster than that of flood tide on a surface layer in the channel east of Doyo-dueng. On the other hand, current speed during ebb tide was slightly faster than that of flood tide on a bottom layer. Current meter records revealed a dominant southward to south-westward current during ebb tide and a dominant northward to north-westward curring during flood tide both on surface and bottom layers. This shows the sediments flux during ebb tide is much higher than that of flood tide on account of dam discharge accelerating the ebb current and subsequently increasing suspended sediment concentration on the seabed. The barrier-island of the Nakdong River Estuary, the only barrier-island in Korea, shows topographical changes under the influence of wave, tide, artificial construction and so on.
Barrier-islands not only serve as a breakwater to reduce coastal disasters caused by high waves, but also form a tidal flat and wetlands, giving rise to development of development of marine ecosystems. The monitoring data obtained through this study will be used as an important data for predicting potential topographic changes in the barrier-islands prior dam removal and identifying the role of barrier-islands in the protection of land masses from natural disasters.

As a result, the KND-1 drilling core obtained in the middle stream of the Nakdong River and the KND-3 drilling core obtained in the down stream are classified into 6 units, respectively.
The Unit-A corresponding the lower part of the drilling core was interpreted as a paleo-channel environment that was highly affected by the land, as it exposed to the terrestrial environment after the last ice age. Unit-B and Unit-C are interpreted as a shallow-marine environment where the sea surface is rapidly rising, deepening the depth of the sea, and thus being affected by the ocean. The upper sections Unit-D and Unit-E were deposited during the formation of delta due to the continued progradation of land sediments. The Unit-F as the top of the drilling core is interpreted as the present Nakdong River delta plain. Therefore, after the last Ice Age, The Nakdong estuary, which was a land environment, changed into the current delta environment through shallow-marine environment due to sea-level rise.

The Nakdong delta system off the Nakdong River estuary consists of a succession of the lowstand systems tract, transgressive systems tract, and highstand systems tract over the sequence boundary formed in the last glacial maximum. The lowstand systems tract is interpreted to be formed in fluvial deposits supplied from paleo-Nakdong River under the exposure of the seafloor during the falling of sea-level. The transgressive systems tract is composed of estuarine deposits, shoreface, and sandridge during the Holocene sea-level rising.
The highstand systems tract shows detaic wedge characterized by sigmoidal progradatational geometry. Recently, the decrease of sediment supply due to the dam construction in the upper Nakdong River is expected to cause not only the change of its morphology but also a significant change of its geological environment such as erosion of surface sediments.

(출처 : SUMMARY 15p)

목차 Contents

• 표지 ... 1
• 제 출 문 ... 3
• 보고서 초록 ... 5
• 요 약 문 ... 7
• SUMMARY ... 13
• CONTENTS ... 21
• 목차 ... 25
• 표목차 ... 29
• 그림목차 ... 31
• 제1장 서론 ... 41
• 제2장 국·내외 기술개발 현황 ... 45
• 제 1 절 국내 기술개발 현황 ... 47
• 제 2 절 국외 기술개발 현황 ... 52
• 제3장 연구개발 수행 내용 및 결과 ... 55
• 제1절 낙동강 하구의 퇴적환경 ... 57
• 1 서론 ... 57
• 2 연구 내용 및 방법 ... 58
• 3 연구 결과 ... 63
• 4 토의 ... 81
• 5 결론 ... 82
• 제2절 낙동강 하구 울타리섬의 소환경 특성 ... 83
• 1 서론 ... 83
• 2 연구 내용 및 방법 ... 84
• 3 연구 결과 ... 87
• 4 토의 ... 95
• 5 결론 ... 99
• 제3절 낙동강 하구 유기 지화학 특성 ... 100
• 1 서론 ... 100
• 2 연구 내용 및 방법 ... 101
• 3 연구 결과 ... 106
• 4 토의 ... 115
• 5 결론 ... 115
• 제4절 낙동강 하구 오염 역사 ... 116
• 1 서론 ... 116
• 2 연구 내용 및 방법 ... 117
• 3 연구 결과 ... 119
• 4 토의 및 결론 ... 126
• 제5절 낙동강 하구 부유 생물 특성 ... 130
• 1 서론 ... 130
• 2 연구 내용 및 방법 ... 131
• 3 연구 결과 ... 133
• 4 토의 및 결론 ... 162
• 제6절 낙동강 하구 저서 생물 특성 ... 163
• 1 서론 ... 163
• 2 연구 내용 및 방법 ... 164
• 3 연구 결과 ... 167
• 4 토의 및 결론 ... 193
• 제7절 울타리섬의 지형 및 지형 변동 특성 ... 195
• 1 서론 ... 195
• 2 연구 내용 및 방법 ... 196
• 3 연구 결과 ... 219
• 4 토의 및 결론 ... 267
• 제8절 다대포 해빈 지형 변화 ... 271
• 1 서론 ... 271
• 2 연구 내용 및 방법 ... 271
• 3 연구 결과 ... 279
• 제9절 낙동강 하구 시추 코어 특성 ... 288
• 1 서론 ... 288
• 2 연구 내용 및 방법 ... 288
• 3 연구 결과 ... 290
• 4 토의 및 결론 ... 300
• 제10절 낙동 델타의 홀로세 층서 진화 ... 303
• 1 서론 ... 303
• 2 연구 내용 및 방법 ... 304
• 3 연구 결과 ... 306
• 4 토의 ... 312
• 5 결론 ... 314
• 제4장 연구개발목표달성도 및 대외기여도 ... 315
• 제 1 절 목표 달성도 ... 317
• 제 2 절 대외 기여도 ... 321
• 제5장 연구개발 결과의 활용계획 ... 323
• 제6장 참고문헌 ... 327
• 부 록 국·내외 학회지 논문 및 위탁연구 결과 ... 339
• 제1절 국내 학술지 논문 ... 343
• 제2절 국외 학술지 논문 ... 441
• 제3절 낙동강 연안 다대포 해빈과 그 연근해 지형 및 지층 연구(위탁연구 결과) ... 549
• 끝페이지 ... 607