• 상하수도학회지
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• 제33권3호
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• pp.177-190
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• 2019

The purpose of this study was to analyze the effects of sewerage facilities through I/I analysis by rainfall by selecting areas where storm overflow diverging chamber is remained due to the non-maintenance drainage equipment when the sewerage system was reconstructed as a separate sewer system. Research has shown that wet weather flow(WWF) increased from 106.2% to 154.8% compared to dry weather flow(DWF) in intercepting sewers, and that the WWF increased from 122.4% to 257.6% in comparison to DWF in storm overflow diverging chamber. As a result, owing to storm overflow diverging chamber of partially separate sewer system with untreated tributary of sewage treatment plant, rainfall-derived infiltration/inflow(RDII) has been analyzed 2.7 times higher than the areas without storm overflow diverging chamber. Meanwhile, infiltration quantity of this study area was relatively higher than that of other study areas. Therefore, it is necessary to reduce infiltration quantity through sewer pipe maintenance nearby river. Drainage equipment maintenance should be performed not to operate storm overflow diverging chamber in order to handle the appropriate sewage treatment plant capacity for rainfall because it is also expected that RDII due to rain will occur after maintenance. In conclusion, it is necessary to recognize aRDII(allowance of rainfall-derived infiltration/inflow) and to be reflected it on sewage treatment plant capacity because aRDII can occur even after maintenance to the complete separate sewer system.

• 한국수자원학회논문집
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• 제56권12호
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• pp.993-1003
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• 2023

대기온실가스 증가로 전지구 평균기온은 산업화 이전 대비 1.1℃ 상승했고 수자원시스템의 공급능력에 상당한 변화가 예상된다. 본 연구에서는 금강수계 내 여러 중권역의 이수안전도와 기후조건의 관계(기후반응함수)를 단변량 함수로 나타내 기후민감도를 동시에 평가할 수 있는 방법을 제안하였다. 사례연구를 위해 GR6J 모형으로 중권역별 자연유출을 모의했고 이를 Water Evaluation And Planning (WEAP) 최적모형에 입력해 2030년 수요전망에 대한 공급신뢰도를 평가하였다. 여러 중권역의 이수안전도를 동시에 비교하기 위해 평균 강수량과 잠재증발산량의 비율을 독립변수 사용하여 단변량 기후민감도 함수를 개발하였다. 사례연구 결과, 1991-2020 자연유출을 이용해 수계전체 물부족을 최소화시키는 운영을 가정했을 때 공급신뢰도는 19개 중권역 중 보청천유역에서 가장 낮았다. 하천유지유량의 우선순위를 농업용수와 생공용수과 동일하게 조정한 시나리오에서는 보청천유역, 초강유역, 논산천유역의 이수안전도가 크게 감소하는 것으로 나타났다. 보청천유역, 초강유역, 논산천유역의 이수안전도는 모든 기후스트레스 테스테에서 크게 감소한 반면, 미호강유역, 금강공주유역, 금강하구유역은 아주 건조한 기후조건에서만 이수안전도가 감소했다. 대규모 인프라에서의 공급이 원활한 중권역의 기후민감도는 크게 변하지 않았다. 2021-2050 기후전망을 민감도함수에 적용했을 때 금강수계의 공급신뢰도는 대체로 좋아질 가능성이 높지만 하천유지유량 우선순위를 높이게 되면 지형적, 인위적으로 고립된 중권역에서 물부족은 심해질 것으로 분석되었다. 2021-2050기간 금강수계의 이수안전도는 기후스트레스 보다 하천관리정책의 변화에 더 큰 영향을 받을 것으로 판단된다.

• 상하수도학회지
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• 제35권5호
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• pp.323-334
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• 2021

Pilot-scale coagulation and sedimentation processes were operated to investigate the T-P (Total phosphorus) removal efficiency. A multiple regression model was also derived to predict the water quality improvement effect with river water characteristics. The inflow rates for the pilot-scale facility were 157-576 m³/day, and the coagulant doses were in the range of 13.7-58.5 mg/L (average 38.9 mg/L) for PAC (Poly alum chloride) and 16.5-62.1 mg/L (average 36.0 mg/L) for alum. The results found that the influent BOD (Biochemical oxygen demand) and T-P concentrations were 4.9 mg/L and 0.115 mg/L, and the removal efficiencies were 52.7% and 59.4%, respectively. T-P removal efficiencies on wet weather days were higher by 10% than dry weather days because influent solids influenced T-P's coagulation process. The pH of river water was 6.9-7.8, and the average pH was 7.3. Although the pH variation was not significant, the trend showed that the treatment efficiency of T-P and PO₄-P removal increased. Thus, the pH range considered in this study seems to be appropriate for the coagulation process, which is essential for phosphorous removal. The T-P removal efficiencies were 19.6-93.3% (average 59.2%) for PAC and 16.4-98.5%(average 55.9%) for alum; thus, both coagulants showed similar results. Furthermore, the average coagulant doses were similar at 42.4 mg/L for PAC and 41.3 mg/L for alum. When the T-P concentration of the effluent was compared by the [Al]/[P] ratio, the phosphorus concentration of the treated water decreased with an increasing [Al]/[P] ratio, and the lowest T-P concentration range appeared at the [Al]/[P] ratio of 10-30. A seasonal multiple regression analysis equations were derived from the relationships between 10 independent and dependent variables (T-P concentration of effluent). This study could help lake water quality maintenance, reduce eutrophication, and improve direction settings for urban planning, especially plans related to developing waterfront cities.

• 한국환경생태학회:학술대회논문집
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• 한국환경생태학회 2003년도 추계학술논문발표회 논문집
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• pp.1-21
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• 2003

I introduce the Flexible Dam Operation (FDO) and some of sediment control techniques In dams which are implemented as trials to avoid or reduce environmental impact of dams on the downstream reaches. The FDO is a dam management method to improve river environment in the downstream reaches by means of the flushing flow, the maintenance flow and so on utilizing a vacant portion of capacity for flood control without interrupting prime flood control function during the rainy/typhoon season. It Is suggested by the guideline of the FDO that EDO should be implemented regularly after the trial for about three years. The basic conception of the FDO is described here. The example of excavation of deposited sediments in check dams and placement of sand ana gravel immediately downstream of the dams and the example of coordinated sediment flushing are described as some of sediment control techniques in dams. Now they are at the stage of experiment and trial. Therefore, it is important to increase examples and establish the technical methodology and the environmental evaluation method for them.

• 한국수자원학회논문집
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• 제44권10호
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• pp.797-807
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• 2011

국내 하천에서 사주 상 식생 활착 현상이 급속하게 진행되고 있다. 1960년대 산업화와 도시화 이전 우리나라 하천은 모래, 자갈이대부분인이른바 'White River (백사장하천)'이었으나, 1970년대이후댐건설, 하천정비등으로유황과유사이 송특성이 교란되어수변에 식생이번무하게 되는이른바 'Green River (식생하천)'가진행중이다. 본 연구는비조절하천사주 상 식생활착에 영향을 미치는 인자 중에서 수위, 수온, 강우, 토양수분, 토양입경 등의 상호연관성을 파악하고자하였다. 이를 위해 우리나라 모래하천인 내성천의 하류를 시험하천구간으로 선정하고, 289일간 모니터링 및 조사 분석을 실시하였다. 또한 과거로부터 현재까지 식생의 경년변화를 파악하기 위해 1970년부터 2009년까지의 항공사진을 분석하였다. 시험하천구간의 범위는 횡단길이 361m, 종단길이 약 2 km이다. 조사 분석 결과 내성천 시험하천구간은 지하수위가 하천수위보다 20~30 cm 가량 높게 나타나는 이득하천이었다. 지하수온은 일별, 계절별 차이가 $5^{\circ}C$ 미만이었고, 하천수온은 식생활착이 본격적으로 시작되는 5월부터 $10^{\circ}C$ 이하로 떨어지지 않았다. 토양수분의 영향인자는 하층은 지하수위, 상층은 강우이며, 상하층은 모두 토양입경에 영향을 받는 것으로 나타났다. 토양수분측정지점 6곳의 지표면~지하 1m까지의 토양은 $D_{50}$ 입경 0.07~1.37mm의 모래이며, 이 입경에서 가능한 모세관 높이는 약 14~43 cm 범위로 추정된다. 한편 비 조절하천인 시험하천구간의 40년간 공간분석 결과, 인위적인 하천교란과 가뭄은 식생활착을 촉진하며, 홍수로 인해 식생군락이 자주 소멸될 수 있음을 확인하였다. 1970년부터 식생의 크고 작은 활착과 소멸이 반복되고 있지만 현재의 식생면적은 과거에 비해 뚜렷하게 증가되어 있다. 식생면적은 시간에 따라 점진적으로 증가하고 있는 것으로 판단된다.

• 한국지역지리학회지
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• 제10권1호
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• pp.192-205
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• 2004

수문환경 변화에 영향을 미치는 요인을 시계열적으로 분석하고, 도시화에 수반되는 물수지 변화를 평가하였다. 그 결과를 요약하면, 다음과 같이 기술할 수 있다. 먼저, 광주천 유역의 하천유출 특성은 6월$\sim$9월 사이에 함양된 저유량에 의해 하천의 기저유출량이 유지되고, 8월에 첨두유량이, 5월에 최저 유량이 나타난다. 도시화 초기단계의 지하수 함양은 강수량대비 46.1%였으나, 1900년대에는 26.5%로 감소하고, 1990년대에는 29.9% 그리고 2010년대에는 27.8%로 감소할 것으로 전망된다. 한편, 직접 유출량은 1960년대에 강수량대비 9.6%였던 것이 1990년대에는 16.2% 그리고 2010년대에는 18.3%로 증가할 것으로 판단된다. 이러한 상태가 지속적으로 유지될 경우, 물수지의 왜곡은 더욱 심화되어 도시형 홍수의 빈발과 광주천의 기저유출량의 감소로 인한 건천화가 더욱 가속화할 것으로 생각한다. 이와 같은 도시수분 현상에 대한 시계열적인 연구는 도시의 재개발 또는 환경정비에 있어서 과거 수문환경을 인식하고, 왜곡된 현상을 파악함으로서 자연친화적 토지이용에 필요한 정보를 제공한다는 점에서 의의가 있으며, 인간활동과 자연환경 간의 상호관계를 규명했다는 점에서 지리학적 연구의 가치가 있다고 할 수 있다.

• 한국농공학회지
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• 제24권2호
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• pp.49-55
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• 1982

The purpose of this study is to classify the factors influenced on the damages of head works suffered from the storm flood occurred on July 22 1980 in both Musim and Bochong rivers and to find out an integral counter measures against the causes influenced on the disaster of head works in the engineering aspect of planning, design, construction and maintenance. In this survey, number of samples was taken 25 head Works, and the counter measures against the causes of their disasters summarized was as follows, 1. In the aspect of planning a. As the flood water level after the establishment of head works is more increased than the level before setting of head works owing to having more gentle slope of river bed between the head works than nature slope of river bed. Number of head works should be reduced for the appropriate annexation of them b. In the place where head works is established on the curved point of levee, the destruction of levee becomes severe by the strong deflective current. Therefore the setting of head works on the curved point should be kept off as long as possible and in case of unavoidable circumstances the construction method such as reinforced concrete wall or stone wall filed with concrete and anchored bank revetments should be considered. 2. In the aspect of design a. As scoring phenomena at up stream is serious around the weir Where the concentration of strong current is present in such a place, up stream apron having impermeability should be designed to resist and prevent scoring. b. As the length of apron and protected bed is too short to prevent scoring as down stream bed, the design length should be taken somewhat more than the calculated value, but in the case the calculated length becomes too long to be profitable, a device of water cushion should be considered. c. The structure of protected river bed should be improved to make stone mesh bags fixed to apron and to have vinyl mattress laid on river bed together with the improvement for increasing the stability of stone mesh bags and preventing the sucked sand from the river bed. d. As the shortage of cut-off length, especialy in case of the cutoffs conneting both shore sides of river makes the cause of destruction of embankment and weir body, the culculation of cut-off length should be taken enough length based on seepage length. 3. In the aspect of design and constructions a. The overturing destruction of weir by piping action was based on the jet water through cracks at the construction and expansion joints. therefore the expansion joint should be designed and constructed with the insertion of water proof plate and asphalt filling, and the construction joint, with concaved shape structure and steel reinforcement. b. As the wrong design and construction of the weep holes on apron will cause water piping and weir destruction, the design and construction of filter based on the rule of filter should be kept for weep holes. c. The wrong design and construction of bank revetment caused the severe destruction of levee and weir body resulting from scoring and impulse by strong current and formation of water route behind the revetment. Therefore bank revetment should be designod and constructed with stone wall filled with concrete and anchored, or reinforced concrete wall to prevent the formation of water flow route behind the wall and to resist against the scoring and impulse of strong stream. 4. In the aspect of maintenance When the damaged parts occurred at head works the authorities and farmers concerned should find and mend them as soon as possible with mutual cooperation, and on the other hand public citizen should be guided for good use of public property.

• 한국구조물진단유지관리공학회 논문집
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• 제10권1호
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• pp.216-222
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• 2006

본 연구는 교각의 형상에 따라 교량하부구조물에 미치는 영향에 관한 연구이다. 유수의 흐름에 의해 교각 주위에서의 하상재료가 침식, 운반, 퇴적작용을 하여 이에 따라 수로의 하상단면은 변화를 하게 된다. 본 연구에서는 흐름과 동일한 방향으로 설치된 일련연속교각에서 교각의 형상변화에 따른 국부세굴 특성을 BOSS SMS로 통하여 분석하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제5권3호
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• pp.225-231
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• 2001

When building tunnels beneath riverbeds where very large quantities of groundwater inflow exist, added to high water head the soil supporting conditions are very poor because the soil consists of sand and silt, etc. It is necessary to have grouting and mini pipe roof installed in the region for ground reinforcement to decrease permeability. According to this result of horizontal boring and laboratory soil testing, ground reinforcement was achieved by L.W grouting for range of 3.0 times the tunnel radius, to increase stability of the tunnel we used the ling-cut method, 0.8m for one step excavation, shotcrete with 25cm thick, steel lib with H-$125{\times}125$. and a temporary shotcrete invert 20cm thick was installed to prevent deformation of the tunnel.

• International Journal of Fluid Machinery and Systems
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• 제6권2호
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• pp.49-55
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• 2013

Water lubricated guide bearing was newly released and has been applied to actual hydro turbines with vertical shaft. As a result, they can have not only high bearing performance but environmental advantages in meeting the demand for reducing river pollution by oil leakage from oil lubricated guide bearing. The PTFE composite guide bearing was tested by experimental equipment operated under conditions similar to those of actual hydro turbines. Circumferential and axial tilting bearing segments help to improve the bearing performance and efficiency due to low friction loss in the bearing system. Furthermore, bearing cooling systems could be eliminated and maintenance periods could be extended, thus the initial investment and operating costs of the hydroelectric power plant are reduced.