• 지질공학
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• 제28권4호
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• pp.529-540
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• 2018

Sand dam is a flow barrier commonly built on small or medium size sandy rivers to accumulate sand and store excess water for later use or increase the water table. The effectiveness of sand dam in increasing the water table and the amount of extractable groundwater is tested using numerical models. Two models are developed to test the hypothesis. The first model is to simulate the groundwater flow in a pseudo-natural aquifer system with the hydraulically connected river. The second model, a modified version of the first model, is constructed with a sand dam, which raises the riverbed by 2 m. In both models, the effect of groundwater abstraction is tested by varying the pumping rate. As the model results show the groundwater after the construction of the sand dam has increased significantly and the amount of extractable groundwater is also increased by many folds. Most importantly, in the second model, unlike the pseudo-natural aquifer system, the groundwater abstraction does not have a significant effect on the water table.

• 대한토목학회논문집
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• 제30권6B호
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• pp.589-598
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• 2010

하천단면의 형상이 복잡하고 교량이나 보등과 같은 수리구조물이 짧은 구간에 연속해서 설치되어 있는 경우, 흐름특성이나 하상변동 양상에 대한 분석이 매우 중요하다. 울산광역시를 관통하는 태화강의 삼호교 부근 약 250 m 구간에는 3개의 교량이 설치되어 있고, 상 하류에 각 1개씩의 지천이 유입되고 있어 홍수시 수위변화와 세굴 등에 의한 단면 변화가 크게 나타난다. 그럼에도 불구하고 태화강이 삼호교(구)를 기준으로 국가하천과 지방하천으로 나뉘는 구간이라는 이유로 상 하류 구간을 1차원 모형을 통해 따로 구분하여 분석하고 있다. 본 연구에서는 1차원 HEC-RAS 모형과 2차원 SMS 모형의 RMA2 모형을 이용하여 교량밀집과 지천유입에 따른 흐름특성을 상 하류 연계하여 비교 분석하였으며, SMS 모형의 SED2D 모형을 이용하여 같은 구간에 대한 하상변동 양상을 분석하였다. 그 결과 연속된 3개 교량에 대한 HEC-RAS 모형 과 RMA2 모형의 수위차는 0.87 m였고, SED2D 모형에 의한 하상변동 모의결과는 교각간격이 좁고 중간에 위치한 삼호교(문화재)에서 최대 0.231 m가 세굴되는 것으로 나타났다. 그러므로 하천기본계획시 교량밀집 지역이나 단면 및 흐름 변화가 심한 구간에 대해서는 2차원 모형에 의한 홍수위 산정과 교각의 세굴에 대한 대책이 필요하고, 국가하천 및 지방하천에 대한 통합적인 분석이 필요하다. 어지는 경우도 있었다. GQPM에 대한 10일강우예측은 첨두강수와 강수총량에 있어서 다소 과소한 모의값을 보이고 있으며, 강수보정효과도 RDAPS에 비하여 저조한 수준이었다. 이 부분은 강수예측의 사후보정으로는 한계가 있는 것으로 보여지며 원시예측모형의 안정화를 통하여 개선할 수 있는 부분으로 판단된다.

• International Journal of Advanced Culture Technology
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• 제11권2호
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• pp.375-380
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• 2023

The study was conducted in Manu-stream, located in Paju, Gyeonggi-do, from January 2021 to December 2021. The survey points were selected in the upper and lower streams based on where thermal discharged to investigate water temperature and fish species and biological community analysis and growth rate were analyzed. The average annual water temperature difference between the upper and lower stream is about 11.0℃, and in the case of the lower stream area, the water temperature is maintained at 20.0℃ or more per year. Fish that appeared during the survey period decreased lower stream compared to the upper stream, which is believed to be the result of a decrease in temperature-sensitive species as the simple riverbed structure and water temperature increased compared to the upper stream. As a result of biological community analysis, it showed a relatively stable community state at the upper stream. The growth rate of fish has a high regression coefficient b value in lower streams throughout the four seasons. It showed relatively good growth lower stream, with a high water temperature. However, the results of each survey point are similar from season to season. The indicator species is a resistant intermediate species, and the range of resistance to water temperature is wide, so it is judged that water temperature's effect on the indicator species' growth is low.

• 한국산업융합학회 논문집
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• 제4권1호
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• pp.51-60
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• 2001

This study examines the effects of removal of the sediment protection weir at Taehwa river mouth on hydraulic and around river environment considering the fact that the effects of the sediment protection weir which is installed to protect water level drop of Ulsan harbor caused by sediments according to flood in Taehwa river, Dong-chun, and so forth may add water quality contamination by flow stagnance in normal and drought period and accumulation of pollutants. The result is as follows. First, it is estimated from the examination of variation characteristics water depth and level for Taehwa river before and after removal of the sediment protection weir that about 0.01m of water depth down according to removal of the sediment protection weir occurs when low flow runs between the sediment protection weir which is located about 2.3km away from the estuary and Samho-gyo which is about 9.0km away from the sediment protection weir, and about 0.01~0.56m(directly upstream point of the sediment protection weir 0.56m, Myongchon-gyo 0.14m, Ulsan-gyo 0.03m, and Taehwa-gyo 0.02m) downs when design flood flows between the sediment protection weir and the upstream of Taehwa-gyo which is 10km away from the sediment protection weir. Therefore, it is thought that variation of hydraulic characteristics of water depth down and so on according to removal of the sediment protection weir is slight because water depth variation is only about 1cm between directly upstream point of the sediment protection weir and Samho-gyo. Next, it is estimated from the examination of variation characteristics of flow velocity for Taehwa river before and after removal of the sediment protection weir that about 0.0lm/s of flow velocity increase occurs between the directly upstream point of the sediment protection weir which is about 2.4km away from the estuary and the directly upstream point of Samho-gyo when low flow runs, and about 0.01~0.44m/s increases between the sediment protection weir and Samho-gyo when design flood flows. Therefore, riverbed erosion by the increased flow velocity is concerned but it is thought that the concern about riverbed erosion is not great because the mean velocity is about 0.07~1.36m/s when low flow runs, and about 1.02~2.41m/s when design flood flows for the sector which experiences the flow velocity variation.

• 한국수자원학회논문집
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• 제36권6호
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• pp.1013-1023
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• 2003

본 연구에서는 최근 환경재료로서 관심이 모아지고 있는 다공성 콘크리트를 하천구조물(보 및 하상재료)에 적용함으로써 수질을 개선하고자 수행하였다. 먼저, 물리ㆍ화학적 특징을 평가해 본 결과, 공극률 10% 및 30%의 다공성 콘크리트의 압축강도는 일반 콘크리트의 최저 압축강도(180 kgf/$cm^2$)를 상회하여 하천구조물에 적용 가능하였고, 알칼리 용출에 의한 부착 미생물에의 영향도 거의 없을 것으로 판단되었다. 또한, 일반 콘크리트와 다공성 콘크리트로 하천구조물을 제작하여 부착물의 성상을 비교ㆍ검토한 결과, 같은 유속조건에서 부착물의 DW량은 일반 콘크리트에 비해 다공성 콘크리트가 1.6배 높은 것으로 나타났으며, 반면에 유속을 10배 달리한 실험의 결과에서는 거의 같은 부착물의 DW량을 보여 부착매질에 의한 영향이 유속에 의한 영향보다도 더 크게 작용한 것을 알 수 있었다. 부착물의 성상에서도 건조물중 AFDM의 비가 다공성 콘크리트에서 더 큰 것으로 나타났으며, 특히 N, P의 비가 높은 것은 부착 생물에 의한 흡수 및 흡착, 물질대사에 의해 유기물 제거가 더 컸기 때문으로 사료된다. 수질개선 효과에 있어서 전 구간을 종합한 결과, 다공성 콘크리트를 적용한 하천구조물에서의 SS, BOD, COD, T-N, T-P의 제거효율은 일반 콘크리트 보다 각각 34.6%, 36.9%, 33.9%, 18.3%, 21.6% 씩 증가하여 하천 수질개선에 크게 기여한 것으로 평가되었다.

• 수산해양교육연구
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• 제27권1호
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• pp.253-261
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• 2015

The chemical water quality and fish assemblage of Dong Stream to assessment of environmental improvement after discharge seawater were investigated from July to December 2013. BOD and DO were significantly different between before and after discharge seawater, while pH and SS did not significant. A total of 11 fish species, 218 individuals and 10,525.1g were collected. Dominant fish species were Mugil cephalus, Konosirus punctatus, Acanthogobius flavimanus and Leiognathus nuchalis which account for 77.5% of total individuals collected, and they were estuarian species. Peak number of species and individuals, and biomass occurred in September, whereas diversity index were highest in November. The water ecosystem of Dong Stream have been changed estuarian environment. As a result of stream assessment on water quality and ecosystem, water quality have been improved as 'III' grade. These results suggested that stream restoration policies such as drain pipes maintenance, management of pollution sources and riverbed dredging to improve environment and recover habitate of Dong Stream were need for set up and establishment of regular monitoring system.

• 한국환경복원기술학회지
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• 제9권4호
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• pp.1-12
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• 2006

The usages of urban riverine areas for the Gapchoen and Yudungcheon in Daejoen City were evaluated by analyzing riverbed characteristics and water quality and by surveying the status of the floodplain usage including questionnaires of people visiting the rivers. Both rivers appear to be stable with insignificant bed changes as the riverbeds are dominated by gravels. Water qualities of both rivers have been improved significantly over the past decade although there are quite large seasonal fluctuations, which is common in most rivers in Korea. The results of floodplain usage analyses show that Gapcheon is dominated with static uses (>70%) such as promenades and resting facilities, while Yudungcheon by dynamic uses (>44%) such as sports facilities. Overall, both rivers require better plans for riverine area usage management considering a balance between the dynamic uses and the static uses such as natural observation places for education and habitats for birds and fish in the rivers. The questionnaire survey results indicate that overall the present status of both rivers are satisfactory and that water quality improvement is one of the key factors to enhance the value of the riverine areas. Future river restoration should be conducted by taking into account the characteristics of urban rivers in harmony with surrounding natural sceneries.

• 지질공학
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• 제30권2호
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• pp.119-129
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• 2020

Sand dam is a successful water harvesting method in mountainous areas with ephemeral rivers. The success is dependent on several factors including material type, hydrogeology, slope, riverbed thickness, groundwater recharge, and streamflow. In this study, the effect of a sand dam on the groundwater level in the Chuncheon area, South Korea was assessed using the MODFLOW model. Using the model, multiple scenarios were tested to understand the groundwater head before and after the construction of the sand dam. The effect of groundwater abstraction before and after sand dam construction and the sand material type were also assessed. The results show, the groundwater level increases substantially after the application of a sand dam. The comparison of model outputs, simulated groundwater head before and after sand dam application with and without pumping well, shows a clear difference in the head. The material type has also an effect on the groundwater head. As the conductivity of the material increases, the head showed a significant rise.

• 한국환경보건학회지
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• 제27권1호
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• pp.51-55
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• 2001

The pollution characteristics of water quality analysis and the heavy metal analysis of river sediment in the Western Nakdong river, and then a commercial tile using the polluted sediment was produced. The analytical results of the riverbed structure and the depth distribution in the Western Nakdong river were that Macdo Stream(site 2) was the deepest(13 ft). The analytical result of water quality showed that BOD was the highest in the Hogei Stream(site 6); COD, Syanduengchi Island(site 1);SS, Macdo Stream(site 2);T-N, Suanduengchi Island(site 1);T-P, Macdo Stream(site 2). Therefore the deeper the site was the higher the pollution concentration was. The result of heavy metal analysis of the river sediment was that Pb and Cr were the highest in Kangdong Bridge(site 9); Cd, Macdo Stream(site 2), so the deeper the site was the higher the pollution concentration was. The production of tile using the mixure of the polluted sediment and the raw material was successful, so the reuse of polluted sediment was possible.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.5-8
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• 2006

The Alternative energy has lately attracted considerable attention due to the high oil price and environment problem. In this study, pilot test facility for using the geothermal energy source from riverbank filtration was constructed and monitoring devices are installed to estimate the efficiency of this system. Initial installation cost can be saved efficiently by connect ing a heat pump system into the exist ing pumping well in Changwon riverbank filtration site. One set of monitoring results during summer was presented and analyzed.