• Journal of Wetlands Research
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• v.14 no.2
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• pp.303-315
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• 2012

This study developed a wetland inventory describing the characteristics and change of Nakdong estuary wetland ecosystem. The data which are used to develop the inventory are Landsat TM(April 1, 1986; June 23, 1987; June 18, 1997), Kompsat(Jan. 12, 2008) and LiDAR(March 1, 2009) images and published monitoring data of Busan metropolitan city. The developed inventory was utilized for the classification of wetland cover, the spatiotemporal analysis of wetland and landscape pattern, the distribution of benthos species etc. Furthermore, the developed 3 dimensional wetland map showed a better way to delineate wetland boundary and understand wetland dynamics. Considering these results, it's concluded that it is possible to use the similar techniques for the development of wetland inventory in Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1224-1229
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• 2007

최근 들어 기상이변으로 집중호우가 발생하여 막대한 홍수피해를 야기하고 있으며, 2003년 발생한 태풍 매미는 전국적으로 엄청난 피해를 유발하였다. 낙동강 유역에서는 이 기간동안 유입유량이 단기간에 집중적으로 유입하는 양상을 나타냈으며, 특히 남강유역 및 밀양강의 유입량 규모는 예년 홍수규모에 비해서 상당히 큰 유입량이 발생하여, 제방과 저수지가 붕괴되어 수많은 재산피해를 남겼다. 이에 건설교통부에서는 낙동강 유역종합치수계획을 수립, 검토하여 유역의 항구적인 수해방지를 위한 방안을 마련하고자 하였다. 본 연구에서는 낙동강 하구둑부근의 치수종합대책(안) 중 우안배수문의 확장방안($47.5{\times}9.2{\times}6$련)에 대하여 홍수위저감효과를 분석함으로써 향후 치수방재대책수립에 만전을 기하고자 하였다. 홍수위 저감효과 분석시 선정된 수리특성분석 모형으로는 유한요소법에 기반을 둔 RMA-2모형의 범용프로그램인 SMS 모형을 이용하였으며, 상류단의 경계조건으로는 유역종합치수계획과 동일한 200년빈도 설계홍수량 조건을 선정하였고, 보다 정확한 분석을 위해 낙동강 하구둑 하류 10km지점에 위치한 명지 조위관측소의 예측조위를 하류단의 경계조건으로 이용하였다. 분석결과 최대수위 발생시간은 대조기 창조시인 약 60시간 후이고, 하구둑 우안배수문을 확장할 경우 하구둑 내측수위가 최대 약 1.32m 저감되는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.28-28
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• 2019

강 하구의 민물과 바닷물이 만나 형성되는 기수역 생태계는 독특한 환경적 가치를 지니고 있다. 낙동강 하구는 우리나라의 대표적인 철새 도래지로 풍부한 생태자원을 지닌 곳이지만, 하굿둑 건설로 기수역이 사라진 이후 기수역 생태계가 갖고 있는 고유의 생태적인 특성이 감소하였다. 한편, 낙동강 하굿둑 건설은 염해피해 방지 및 부산, 울산, 창원 등의 지역에 추가적인 용수공급을 가능하게 도왔다. 이에 낙동강 기수역 생태계 복원을 위한 하굿둑 개방과 용수공급 및 염해피해 방지 등을 위한 하굿둑 운영에 대한 논의가 지속되어 왔다. 낙동강 하구관리에 대한 합리적인 의사결정을 위해서는 하굿둑 건설 및 운영에 따른 편익과 동시에 낙동강 하구 기수역의 생태 환경적 가치도 함께 고려해야한다. 이에 본 논문에서는 낙동강 하구의 기수역 생태 복원에 초점을 맞추어 이와 관련된 환경적 가치를 조건부 가치측정법이라는 경제학적 기법을 적용하여 추정하고자한다. 전국 800가구를 무작위로 추출하여 일대일 개별면접을 통해 낙동강 기수역의 생태복원에 대한 지불의사액을 조사하였다. 이 정보는 낙동강 하구관리에 대한 의사결정시 활용할 수 있다.

• Journal of the Korean Geotechnical Society
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• v.22 no.11
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• pp.133-142
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• 2006

Pusan clay, which is distributed in the Nakdong River estuary, is unusually soft and thick compared with other clays in the world. Because the consolidation settlement of the clay was significantly underestimated in several recent reclamation projects, it has been emphasized particularly on the need of studying the permeability characteristics. This study carries out vertical and horizontal permeability tests on undisturbed and consolidated samples from two sites of the area. The results of the study show the peculiar permeability anisotropy and the relationships with other indexes on Pusan clay and also comparison with those of other world clays.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.167-167
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• 2020

Annual sediment deposition in reservoirs behind weirs poses flood risk, while its accurate prediction remains a challenge. Sediment management by hydraulic flushing is an effective method to maintain reservoir storage. In this study, an integrated approach to predict sediment inflow and sediment flushing simulation in reservoirs is presented. The annual sediment inflow prediction was carried out with Artificial Neural Networks (ANN) modelling. RESCON model was applied for quantification of sediment flushing feasibility criteria. The integrated approach was applied on Sangju Weir and also on estuary of Nakdong River (NREB). The mean annual sediment inflow predicted at Sangju Weir and NREB was 400,000 ㎥ and 170,000 ㎥, respectively. The sediment characteristics gathered were used to setup RESCON model and sediment balance ratio (SBR) and long term capacity ratio (LTCR) were used as flushing efficiency indicators. For Sangju Weir, the flushing discharge, Q_f = 140 ㎥/s with a drawdown of 5 m, and flushing duration, T_f = 10 days was necessary for efficient flushing. At NREB site, the parameters for efficient flushing were Q_f = 80 ㎥/s, T_f = 5 days, N = 1, El_f = 2.24 m. The hydraulic flushing was concluded feasible for sediment management at both Sangju Weir and NREB.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.412-419
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• 2005

The dynamics of zooplankton community and its relationship with environments were studied at the middle stretch (Waekwan, RK; river kilometer; above 175 km from the estuary dam) of large regulated river, Nakdong River from 1998 to 2002. There were distinct inter-annual variations and seasonal changes in total zooplankton abundance in the study site (ANOVA, p<0.01), displaying similar pattern in three years from 1999 to 2001 except 1998 and 2002. The annual average rotifers abundance during the study period was 43${\pm}76 ind. $L^{-1}$ (mean${\pm}$s.d., n = 118), followed by adult copepodids (1.6${\pm}$4.8 ind. $L^{-1}$), and small cladocerans (0.4${\pm}$1.2 ind. $L^{-1}$). Among the rotifers, Brachionus spp. Polyarthra spp., Colurella spp., Keratella spp.·, and Trichocerca spp. were the most common taxa. These species occupied more than 80% of the total rotifer abundance throughout the study period. Total zooplankton abundance rapidly increased in spring and fall and remained low throughout the winter. During summer, zooplankton dynamics seemed to be largely affected by hydrological parameters. Overall, rather the external factors (hydrological factors of the river) than internal factors (food condition for zooplankton such as phytoplankton biomass) appear to be responsible for changes in zooplankton dynamics in the middle stretch of the river.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.106-127
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• 2019

This study aims to understand spatio-temporal variations of macrozoobenthos community in Han River (HRE), Geum River (GRE), and Nakdong River estuaries (NRE) of Korea, sampled by National Survey of Marine Ecosystem. The survey was seasonally performed at a total of 20 stations for three years (2015-2017). Sediment samples were taken three times with van Veen grab of $0.1m^2$) areal size and sieved through a 1 mm pore size mesh on site. A total of 1,008 species were identified with 602 species in HRE, 612 in GRE, and 619 in NRE, showing similar number of species between estuaries. Mean density was $1,357ind./m^2$, showing the high in NRE ($1,357ind./m^2$), mid in GRE ($1,357ind./m^2$), and low in HRE ($1,127ind./m^2$). Mean biomass was $116.8g/m^2$, showing similar variations to density ($174.2g/m^2$ in NRE, $129.0g/m^2$ in GRE, $49.0g/m^2$ in HRE). Polychaeta dominated in number of species and density in three estuaries. Biomass-dominated taxon was Mollusca in HRE and GRE, and Echinodermata in NRE. Polychaetous species dominated all three estuaries over 4% of density, such as Dispio oculata, Heteromastus filiformis and Aonides oxycephala in HRE, Heteromastus filiformis and Scoletoma longifolia in GRE, and Pseudopolydora sp. and Aphelochaeta sp. in NRE, showing various density between estuaries. Community structure was determined by various environmental variables among estuaries such as mean grain size and sorting (HRE), salinity and mean grain size (GRE), and salinity, dissolved oxygen, loss on ignition and mud content (NRE). Our study demonstrates the application of different measures to manage ecosystems in three estuaries. HRE needs to alleviate sedimentary stressors such as sand mining, land-filling, dike construction. Management of GRE should be focused on fresh water control and sedimentary stressors. In NRE, monitoring of dominant benthos and process study on hypoxia occurrence in inner Masan Bay are necessary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.111-117
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• 2008

We estirmted the yearly and monthly variation in discharge from the Nakdong River Barrage. We studied the total monthly discharge, the mean daily discharge, and the maximum daily discharge based on the observational discharge data for the 11-year period 1996-2006. We also examined the correlation between the discharge and the meteorologiml factors that influence the river inflow. The results from this study are as follows. (1) The total monthly discharge for 11 years at the Nakdong River Barrage was $224,576.8{\times}10^6\;m^3$: The daily maximum was in 2003, with $56,292.3{\times}10^6\;m^3$. The largest daily mean release discharges occurred in August with $52,634.2{\times}10^6\;m^3$ (23.4% of the year), followed by July and September in that order with 23.1 and 17%, respectively. (2) The monthly pattern of discharge could be divided into the flood season for the period July-September (discharge =$1000{\times}10^6\;m^3$/day), the normal season from April to June and October (discharge=$300{\times}10^6\;m^3$/day), and the drought season from December to March (discharge < $300{\times}10^6\;m^3$/day). (3) Periods of high temperature, low evaporation loss, and short sunshine duration produced a much higher discharge in general. Conditions of low rainfall and high evaporation loss, as was the rose in 2003, tended to reduce the discharge, but high rainfall and low evaporation loss tended to increase the discharge as it did in 200l. (4) The dominant wind directions during periods of high discharge were NNE (15.5%), SW and SSW (13.1%), S(12.1%), and NE (10.8%) This results show that it run bring on accumulation of fresh water when northern winds are dominant, and it run flow out fresh water toward offslwre when southern winds are dominant.

• Journal of the Korean GEO-environmental Society
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• v.17 no.2
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• pp.31-39
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• 2016

Vertical drain has usually been used to accelerate the consolidation of soft clay deposits with high moisture content. Busan thick clay deposits are subjected to artesian pressure from an aquifer in sand and gravel layers. However, effect of artesian pressure existing in drainage-installed soft ground on consolidation behaviors is not well known. This paper investigates the consolidation behavior of drainage-installed soft ground at the Nakdong river estuary with artesian pressure and without artesian pressure. A series of one-dimensional large size column test was carried out to find out the consolidation characteristics of clay. Test results indicated that total settlement of clay with artesian pressure was higher than that without artesian pressure because effective stress decreased due to upward flow. Dissipation rate of excess pore water pressure delayed and excess pore water pressure did not fully dissipate in clay layer with artesian pressure. Undrained shear strength of clay ground with artesian pressure was lower than that without artesian pressure.

• Development and Reproduction
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• v.8 no.1
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• pp.43-47
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• 2004

The present paper studied neurosecretory cell types and their seasonal secretory activity in the eyestalk of Palaemon macrodactylus. The samples were monthly collected in Nakdong estuary for one year. The eyestalk consisted of lamina ganglionaris, medulla externa medulla interna, and medulla terminaris. four types of neurosecretory, A-, B-, C- and D-cells are found in the eyestalk. The A-cells are located in the medulla externs. Althoush the B- and C-cells are located in the medulla interna and medulla terminalis, B-cells are predominant in medulla interna and C-cells are usually distributed in medulla terminaris. The size of D-cells are larger than other types of cells in size. The neurosecretory cells except D-cells show a remarkable change with month. The A-, B-, and C-cells are activated from March and April to July, and decreased at August.