• Journal of Korean Society of Water and Wastewater
• /
• v.31 no.1
• /
• pp.29-37
• /
• 2017

To estimate pollution sources in the watershed with various industries, the simulation of contamination route and distribution of 2-methyl-4,6-dinitriophenol(DNOC) were performed with a numerical model Hydro Geo Sphere. This study was performed calculations of the load using the measured concentration and simulated flow rate. And, the river was divided by the sampling sites at the mainstream, and the contribution rate at downstream sampling sites was calculated for each section. The results showed the concentration of the downstream sampling sites were decided by the concentration of upstream sites, and the contribution rates of the tributaries were calculated below 10%. The results also showed that the impact of the potential sources in Section 1(Geumho1 ~ Geumho2) and Section 5(Geumho5 ~ Geumho6) was larger than in the other area. In Section1 and Section5, It seemed to require detailed investigation.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1306-1310
• /
• 2009

The roughness coefficients were estimated by the Manning's equation for the measured stage and flow velocity of Bocheong stream basin in Kum river. The relationships between the estimated roughness coefficients and the geomorphologic factors were formulated by the linear, logarithmic, exponential and power type function, thereafter correlation equations were presented. The correlation analysis was performed between the measured stream length and the basin area of Bocheong stream basin by the linear, logarithmic, exponential and power type function, and correlation equation for the stream length was given. The roughness coefficient has strong correlationship with stream slope, but low correlation coefficients with stream length and basin area. For the correlationship with the roughness coefficients and the stream slope, the logarithmic type function has the smallest correlation coefficient, on the other hand, the exponential type function has the largest correlation coefficient. For the relationship between the stream length and the basin area, the correlation coefficient of the logarithmic type function shows the smallest value, linear type function shows the largest value.

• Journal of Ship and Ocean Technology
• /
• v.10 no.1
• /
• pp.1-9
• /
• 2006

The resistance reduction by an air lubrication effect of a large air cavity covering the hull bottom surface and the similarity relations involved have been investigated with a series of towing tank tests of three geometrically similar models. The test results of geometrically similar models have indicated that a large air cavity was formed beneath the bottom having a backward-facing step by artificially supplying air is effective for resistance reduction. The areas of air cavity and the required flow rates of air are directly related to the effective wetted surface area. The traditional extrapolation methods seem to be applicable to the estimation of the resistance in the tested range if corrections are made to account the changes in the frictional resistance caused by the changes in the effective wetted surface area. To investigate the effectiveness of air lubrication in improving the resistance performance of a practical ship, a small test boat having a backward-facing step under its bottom has been manufactured and speed trials in a river have been performed. Air has been supplied artificially into the downstream region of the bottom step to form a large air cavity covering the bottom surface. The results have confirmed the practical applicability of air lubrication for the resistance reduction of a small high-speed boat.

• Korean Journal of Environmental Biology
• /
• v.22 no.1
• /
• pp.227-232
• /
• 2004

Hydrological and biological studies on ecosystems of the lakes 'etang de Berre' and 'etang de Vaime', the four rivers flowing into these lakes, and the Mediterranean Sea are carried out during the whole two-year period. The phytoplankton population of the lakes 'etang de Berre' and 'etang de Vaine' is larger than that of the seawater or freshwater populations of four neighbouring rivers. This is due to the increasing nutriments such as phosphate, nitrate, and silicate flowing into the lakes from the four rivers. The superfluous phytoplanktons in the lakes flow into the Mediterranean Sea via the Caronte Canal. Phytoplanktons multiplicated by phosphate of lake 'etang de Berre' can produce 10,160 tons of assimilated carbon per year, and those multiplicated by nitrate produce 18,450 tons of assimilated carbon per year. According to Steeman Nielsen's primary production estimation, phytoplanktons produce about 45,000 tons of carbon per year through assimilation in lake'4tang de Berre' and 10,000 tons of carbon per year in lake 'etang de Vaime'. The amount of carbon produced by phytoplanktons and the amount of phosphate, and nitrate are different according to the sea, river, and estuary.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.599-603
• /
• 2012

본 연구에서는 부정류 계산 모형을 이용한 확률 홍수량 및 홍수위 산정 방법을 개발하고, 이를 한강 살리기 사업이 진행 중인 남한강 구간에 적용하였다. 우선 한강 살리기 사업 전과 후의 하도에 대하여 부정류 계산 모형을 각각 수립하였으며, 과거 발생한 홍수사상을 조사하였다. 사업 전 모형과 최근에 발생한 홍수사상을 이용하여 모형의 보정 및 검증을 실시하고, 추정된 매개변수를 사업 후의 하도에 대한 모형에 적용하였다. 대상 유역에 과거 발생한 홍수사상을 사업 후 모형으로 모의하여 각 홍수사상 별로 최대 홍수량 및 홍수위를 계산하였다. 이때 최대 홍수량 모의 결과들을 빈도해석 대상 자료군으로 사용하여, 연최대치 계열이나 부분 시계열에 대하여 빈도해석을 통하여 확률 홍수량을 산정할 수 있다. 본 연구에서는 장기간의 관측자료의 확보가 어려운 국내의 현실을 고려하여, 부분 시계열의 빈도해석 방법을 사용하여 확률 홍수량을 산정하였다. 다음으로 부정류 계산모형의 모의 결과인 최대 홍수량 및 홍수위 자료를 회귀분석하여 수위-유량 관계식을 유도하고, 각 빈도별 확률 홍수량을 관계식에 대입하여 확률 홍수량에 대응하는 확률 홍수위를 산정하였다.

• Proceedings of the KAIS Fall Conference
• /
• 2007.11a
• /
• pp.367-370
• /
• 2007

한국수자원공사에서 개발한 유출모의 모형인 RRFS의 입력자료로 사용되는 소유역별 각 용수에 대한 회귀율은 생공용수의 경우에는 65%, 농업용수의 경우에는 35%로 하여 일괄적으로 입력되어 있으나 이러한 값은 대략적으로 추정된 값이다. 따라서 본 연구에서는 금강수계내 전체에 대한 용수체계도를 대청댐 상류, 청주권, 대전권, 대청댐 하류 및 하구언권으로 구분하여 각 권역별로 작성하여 유출체계에 의한 메커니즘을 도시하였다. 본 연구에서는 체계적인 용수이용별 물이용수급현황 분석을 통해 물이용현황을 파악하는 것에 목적을 삼고 용수계통도 작성을 통한 권역별 용수체계를 분석하고자 하였다. 금강유역내 총 14개의 소유역에 대한 용수계통도 작성을 통해 용수수급현황을 분석하고, 궁극적으로 용수수급현황도를 작성하고자 각 권역별 하천 수계현황 조사, 용수사용현황 조사, 주요 용수시설물 현장조사 및 용수계통도를 작성하였다.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.63 no.6
• /
• pp.89-100
• /
• 2021

The conservation of stream habitats has been gaining more public attention and fish habitat suitability index (HSI) is an important measure for ecological stream habitat assessment. The fish habitat preference is affected not only by physical stream conditions but also by water quality of which HSI was not available due to the lack of field data. The purpose of this study is to estimate the HSI of Zacco platypus for water quality parameters of water temperature, dissolved oxygen (DO), and biochemical oxygen demand (BOD) using the water environment monitoring data provided by the Ministry of Environment (ME). Fish population data merged with water quality were constructed by spatio-temporal matching of nationwide water quality monitoring data with bio-monitoring data of the ME. Two types of the HSI were calculated by the Instream Flow and Aquatic Systems Group (IFASG) method and probability distribution (Weibull) fitting for the four major river basins. Both the HSIs by the IFASG and Weibull fitting appeared to represent the overall distribution and magnitude of fish population and this can be used in stream fish habitat evaluation considering water quality.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.247-247
• /
• 2020

생태유량은 하천에 서식하는 동·식물 등의 서식처 조건을 고려하여 갈수시에도 최소한의 하천생태계가 유지될 수 있도록 하는 유량이다. 이는 하천의 적정유량으로 적용할 수 있는 생태적 기준의 하나이며 수생생물의 물리적 서식처 적합도를 이용하여 산정할 수 있다. 특히 하천 생태계의 먹이 사슬 상층부에 속하는 어류는 서식처의 물리적 조건에 민감하므로 적절한 유량을 보장해 주는 것이 중요하며, 이러한 이유로 생태유량 산정에 어류의 서식처 조건이 주로 이용된다. 본 연구에서는 다목적댐의 건설과 준설 및 매립 등으로 유황 변동과 하류 염해 피해 등에 의한 하구 생태계 변화 등을 겪고 있는 섬진강 수계를 대상으로 송정, 겸백, 화개 세 지점에 대해 생태유량을 산정하였다. 이 생태유량은 섬진강 수계에서는 직접 측정에 한계가 있어 금강에서 측정된 피라미의 서식처 적합도 지수를 이용하였고, 지점의 하상재료 및 환경 조건을 반영하여 PHABSIM을 이용하여 산정되었다. 그 결과 송정의 최적 생태유량은 8.5㎥/s, 겸백은 2.26㎥/s, 그리고 화개 지점은 36㎥/s로 산정되었다. PHABSIM을 이용한 생태유량 산정 값은 지점에 따라 다소 과대 추정되는 경향이 있기도 하지만, 섬진강 수계의 해수 침투 등에 의한 염해 피해 대책 마련 등을 위해서는 산정된 유지유량을 확보하기 위한 해결 방안이 제시되어야 할 것으로 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.6
• /
• pp.353-360
• /
• 2010

The Kyunggi Bay in mid-west of Korea is a relatively large estuarine system that connects the Han River system with Yellow Sea. Due to macro-tidal range of more than 8 m, the urban estuary shows deep tidal channels and wide tidal flats. Since last 30 years, the coastal development is undergoing, yielding noticeable change in environment. Particularly the tidal flat dynamics are generally accepted as being related with tidal residual flows in this area (Kim et al., 2009). We have estimated the annual variation and vertical structure of residual currents with one-year long observed flows in two major tidal channels of Kyunggi Bay. The moving average method and tidal current harmonic analysis yield nearly the same results on residual flow. The residual flow in Jangbong channel ranges from 20 cm/s in summer to 30 cm/s in winter. It is noticeable that the residual flow in Jangbong channel is flood dominant throughout the year, while the flow in Seokmo channel is ebb-dominant residual flow with current speed range of 20-40 cm/s. Due to the baroclinic response of relatively shallow estuary, significant reduction of energy in bottom layers have been observed, indicating the importance of residual circulation to the tidal flat behavior.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.7 no.2
• /
• pp.1-15
• /
• 2004

For the simulation of flow phenomenon that calculate basin outflow, it is required to estimate effective precipitation which contributes to direct runoff. This paper is focused on using detailed soil map which is one of the data required to estimate effective precipitation by SCS CN method. Korean detailed soil map must be reclassified as SCS hydrologic soil group when it is applied to SCS CN method. In this study, Korean detailed soil maps which are reclassified as SCS hydrologic soil group by the methods of Her and Jung (1987) and Jung et al. (1995) are applied to flow simulation and the results are analyzed. The study sites are Wichon watershed and Pyungchang river basin which are studied by International Hydrological Program(IHP). HEC-1 and WMS v6.1 are used to simulate flow phenomenon and calculate geographic parameters. The difference of flow analysis results from each soil reclassification method is different from each sites. But the results of flow analysis approximate observed data by using Jung et al. (1995) method more than Her and Jung (1987) method.