• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.2B
• /
• pp.109-119
• /
• 2011

In this study, the flow characteristics of Han River Estuary were investigated by using a two-dimensional numerical model according to the assumption of shift and modification of the Shingok submerged weir. The two-dimensional analysis has contributed to our understanding of the hydraulic effects induced by shift of the weir on the topography, especially wetlands. The tide and flow discharge of 2007 were adopted as an input data for the simulation. The tidal data contained both spring and neap tide, and the flow discharge condition was divided into monsoon and normal seasons. The boundaries of this study were Hangang Bridge, Tongil Bridge, and Yu island. The simulation results showed that influence area of seawater changed depending on the weir shift, and the water level at particular station fluctuated according to the condition of tide and flow discharge.

• Journal of Korea Water Resources Association
• /
• v.48 no.9
• /
• pp.695-709
• /
• 2015

The inflow of nonpoint pollution sources due to sustainable development and urbanization is gradually increasing and causes a diversity of water pollution. There are lots of difficulties to find a solution as the problems related to variation of hydrological and natural phenomenon. A differentiated method to estimate the nonpoint pollution sources has been proposed using rainfall and characteristics of urbanization and observed data from sewage treatment districts in the study. The types of nonpoint pollution sources on an assumption of combined sewer system have been classified as three types which are inflow of rainfall, bypass of sewage treatments, and combined sewer overflows from a river. Three types for estimation of nonpoint pollution sources applied more accurately to generate a amount of nonpoint pollution loads. This study is expecting a wide application for effective water resource management on TMDL (total maximum delivery load) unit watershed and sewage treatment districts.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.91-91
• /
• 2019

아열대 해양성 기후로 변화하고 있는 다우지역인 제주도는 각종개발 등 도시화로 인한 불투수층 증가가 급증하고 있으며 기후 변동에 의한 강우량은 더욱 늘어 홍수 피해가 빈번히 발생하고 있어 저영향개발기법(LID, Low Impact Development)을 통한 빗물을 지하로 침투시켜 지하수 보호 및 확보와 동시에 재해 저감을 할 수 있는 기술개발이 시급한 실정이다. 현재 설치된 재해저감방식 중 침투트렌치에 의한 침투방식은 제주도의 보전자원인 화산석인 현무암을 주 재료로 하고 있어 2차환경 파괴를 야기 시키고 있지만 암을 보전하고 대처할 수 있는 신재료와 신기술 관련 침투방식의 성능 극대화에 대한 연구가 미진하며, 지하수를 주 수원으로 하고 있는 제주도에서 초기 강우 배제 없이 침투시킬 경우 지하수 오염 가능성도 상존하고 있다. 본 연구는 지하수의 제주형 인공함양정과 재해영향평가 지침에서 제시한 암을 충진하는 정형화된 침투식 방법을 개선하여 초기 강우의 수질오염을 억제하면서 지하수 인공함양과 재해저감을 위해 침투와 저류를 동시에 할 수 있는 신기술을 상용화와 침투형 저류지의 설치 초기비용 및 유지비용을 절감하고 부지확보에 따른 사업자의 부담을 경감 할 수 있는 침투트렌치 형식의 침투저류시스템을 개발하여 실용화하는데 있다. 이에 따라 본 연구에서는 제주도인 경우 일시적 높은 첨두유량으로 인해 지표유실 및 침수범람이 빈번하게 발생하고 도시화에 따른 포장면적 증가로 지표수 유실이 증대 되는 점을 감안하여 이를 저감하기 위한 첨두유량의 해결방안으로 저류용 침투저류조 내 유입수의 신속한 침투기능과 지하수 함양 증대에 기여 등 제주형 집중호우 대비 침투저류조 설치에 따른 효과 및 적용 가능성을 조사하였다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.19 no.3
• /
• pp.274-280
• /
• 1986

Velocity variability of Masan Inlet in the northernpart of Chinhae Bay is studied on the basis of the cross-sectional net velocity distributions and its root-mean-square. They were calculated during three consecutive cycles at spring tide as well as two cycles at near tide with precipitations in June and July 1985. During the spring tide, net ebb flow take place in the western channel while net flood flow in the eastern channel of the cross-section. On the contrary, the direction of both net flows during the neap tide with precipitations is reversed. R.M.S. isotachs show that the highest velocity is 15 cm/sec at spring tide and 10.3 cm/sec at neap tide, and the greatest velocity is persistently found at the surface layer of the western channel of the cross-section at each tidal cycle. It is shown that the major part of constituents of the constant flow in the Inlet is the tidal residual current. The density-driven current, however, plays an important role afer the heavy precipitations.

• Plant Journal
• /
• v.15 no.1
• /
• pp.38-44
• /
• 2019

This research is an experimental investigation to find the desirable pH of slurry in the desulfurization absorber for a 1000 ㎿ coal fired power plant, operating in compliance with the Air Environmental Conservation Act and the plant's internal regulations. In case the average sulfur dioxide concentration in inflow flue gas, ${\bar{C\;in}}$ [ppm] changed to 500 ppm, 550 ppm, 600 ppm and 635 ppm after fixing inflow flue gas flow rate, generator output, pressure drop in the absorber, and oxidation air flow rate, the desirable pH of the slurry in the absorber, was 5.0, 5.2, 5.3 and 5.4. Thus, it is recommended that the desirable pH of slurry is calculated using the correlation equation, $RpH=0.0018{\times}{\bar{C\;in}}+4,2031$ when the average sulfur dioxide concentration in the inflow flue gas is in the range of 500 ppm to 635 ppm.

• Journal of Korea Water Resources Association
• /
• v.49 no.5
• /
• pp.391-398
• /
• 2016

The confluence section of rivers forms complex flow pattern due to inflow discharge variation at the mainstream and tributary. Due to complex flow characteristics, bed change and bank erosion at the local section produce lateral geomorphology changes in rivers. In this study, bankline change by bank erosion and bed change were simulated using CCHE2D of 2-dimensional numerical model for quantitative analysis of lateral changes in the confluence section of South Han River and Geumdang Stream. As a result, bankline at the left-side channel of the mainstream was largely changed in the downstream section of the confluence compared to the upstream section. Also, bank erosion in the tributary was hardly occurred and bankline at the left-side tributary and right-side main stream moved to riverside land due to decreased velocity and deposition.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.61-61
• /
• 2019

우리나라는 대부분이 산지(약 65%)로 구성되어 있어 강우 시 그 공간적 분포의 변동성이 매우 큰 편이며, 특히 전형적인 산지지형인 댐 유역의 경우 고도 변화 등에 기인한 지형특성 등에 따라 강우의 형태 및 패턴과 이에 따른 유출변화가 큰 복잡한 특성을 갖는다. 이로 인해 단순히 지점강우들을 공간보간(평균)한 면적강우를 홍수 유출모의 등에 활용할 경우 그 신뢰도가 매우 낮은 경우가 많아, 수문모의에 있어 레이더에 기반을 둔 공간 분포형 강우 등의 도입 검토가 요구된다. 한편, 최근 기상청에서는 보다 정확한 레이더 강수량 추정 값의 제공을 위해 "레이더-AWS 강우강도(Radar-AWS Rainrates, RAR)" 산출 기술을 지속적으로 개선하고 있으며, 이는 지상 우량계 대비 상당한 정확도를 보이고 있다. 본 연구에서는 국내 산지지형을 대표하며, 타 댐 유역에 비해 비교적 수문(수위/유량)관측소와 자료가 많은 용담시험유역에 기상레이더 강수량 추정 값(RAR)을 적용해 산지지형 댐 유역에서 강우의 시공간적 변동성과 이에 따른 홍수량의 정확한 분석을 통해 홍수 시 댐 유입량의 정확한 산정 등에 활용할 목적으로 홍수 유출모의를 수행하고자 한다. 모의에는 최근 5년(2014~2018년)동안 발생한 비교적 독립적인 1~2개(연도별)의 홍수사상을 적용하였으며, 모형은 분포형 강우를 적용할 수 있는 비교적 간단한 모형인 HEC-HMS를 활용하였다. HEC-HMS는 주로 집중형 수문모형(Lumped Hydrologic Model)으로 분류되어 레이더 강우와 같은 분포형 자료의 입력을 주로 적용치는 않고 있지만, HEC-GeoHMS와 ModClark 방법을 활용하면 격자단위의 분포형 강우를 적용할 수 있는 형태의 모델 구축이 가능하다. 모의 결과는 기존 유역평균 강우를 적용한 방법과 비교를 통해 그 개선점을 검토하고자 하며, 이를 통하여 산지지역 댐 유역의 홍수특성을 보다 더 정확하게 분석해보고자 한다. 한편, ModClark을 적용한 홍수 유출모의는 단순히 소유역별 도달시간의 격자별 비율을 고려한 홍수추적으로 그 해석상의 한계가 있어, 최근 개발된 하이브리드 수문모형(Hybrid Hydrologic Model, Distributed-Clark) 등도 동일유역에 대해 도입 적용할 계획에 있다.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.10 no.2
• /
• pp.67-85
• /
• 2007

A three-dimensional hydrodynamic model with the fine grid is applied to simulate the barotropic tides, tidal currents, residual currents and salinity dispersions in the Yellow Sea and the East China Sea. Data inputs include seasonal hydrography, mean wind and river input, and oceanic tides. Computed tidal distributions of four major tides($M_2,\;S_2,\;K_1$ and $O_1$) are presented and results are in good agreement with the observations in the domain. The model reproduces well the tidal charts. The tidal residual current is relatively strong around west coast of Korea including the Cheju Island and southern coast of China. The current by $M_2$ has a maximum speed of 10 cm/s in the vicinity of Cheju Island with a anti-clockwise circulation in the Yellow Sea. General tendency of the current, however, is to flow eastward in the South Sea. Surface residual current simulated with $M_2$ and with $M_2+S_2+K_1+O_1$ tidal forcing shows slightly different patterns in the East China Sea. The model shows that the southerly wind reduces the southward current created by freshwater discharge. In summer during high runoff(mean discharge about $50,000\;m^3/s$ of Yangtze), low salinity plume-like structure(with S < 30.0 psu) extending some 160 km toward the northeast and Changjiang Diluted Water(CDW), below salinity 26 psu, was found within about 95 km. The offshore dispersion of the Changjiang outflow water is enhanced by the prevailing southerly wind. It is estimated that the inertia of the river discharge cannot exclusively reach the around sea of Cheju Island. It is noted that spatial and temporal distribution of salinity and the other materials are controlled by mixture of Changjiang discharge, prevailing wind, advection by flowing warm current and tidal current.

• Korean Journal of Environmental Biology
• /
• v.22 no.1
• /
• pp.57-65
• /
• 2004

In order to determine the effect of fresh water inflow from the Heongsan river on the changes of water quality in the Yeongil Bay (Korea), the seasonal changes of water temperature, salinity, chemical oxygen demand (COD), dissolved inorganic nitrogen(DIN) and phosphate phosphorus ($PO_4$-P) concentrations were examined using the data set obtained five fixed points of Yeongil Bay from 1998 to 2000. The distributions and changes of COD and concentrations of total inorganic phosphorous (TIP) and nitrogen (TIN) at three points Heongsan river, were also compared with those of Yeongil Bay. Based on the correlations of DIN and $PO_4$-P, it was found that the inflow of freshwater affected on the water quality of Yeongil Bay. Such a complicacy was confirmed by the prominent differences in n few water quality measures between Site 1(the innermost area) and Site 5 (the mouth of the bay). The negative correlations in $\Delta N/\Delta P $ at sites 1, 2 and 3 of the inner-part of the bay also indicated a large effect of freshwater inflow on the water quality of the bay. The extremely low atomic ratio of an average of 6.4 in $\Delta N/\Delta P $ compared to the Redfild ratio suggested that the DIN was depleted in the overall bay system. In contrast, it was inferred that the excessive PO$_4$-P concentration was due to the inflow of freshwater from the Heongsan river.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.9
• /
• pp.469-475
• /
• 2016

The study is the result of an practical operation analysis for the full scale fishery product wastewater treatment plant with immersed MBR (iMBR) process. Since fishery product industries show a wide range of wastewater generation by the season, design and operation of the equalization basin are very important factor. The aeration system for the equalization basin mixing can save the chemical consumption for followed system through the restriction of acid fermentation. The concentrations of wastewater primary DAF process treated were BOD 2,291 mg/L, $COD_{Mn}$ 530 mg/L, SS 256.8 mg/L, T-N 38 mg/L, T-P 13.5 mg/L respectively. It was considered that iMBR is the most efficient biological process for high salinity content wastewater since It is irrelevant to the capability of the sludge precipitation. SADp and SADm were 0.31, $26.5m^3/hr{\cdot}m^3$ respectively. In iMBR process, the critical F/M ratio was derived at 0.08~0.10 gBOD/gMLSS by analysing the correlations between MLSS, normalized TMP and temperature. The effluent concentrations were BOD 1.8 mg/L, $COD_{Mn}$ 12.4 mg/L, SS 1.0 mg/L, T-N 7.85 mg/L, T-P 0.1 mg/L and removal efficiencies were 99.9%, 97.6%, 96.3%, 95.7%, 97.8% respectively.