• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.888-892
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• 2004

농지, 임야지역에서의 강우유출수 수질의 파악은 수자원 수질관리에 있어서 바탕수질(Background water quality)이기 때문에 물관리에 있어 매우 중요한다. 본 연구는 농지와 임야가 혼합된 도시외곽지역에서 강우시에 발생하는 강우유출수의 수질 및 오염부하량에 대하여 유역특성이 다른 두 지역에서 분석을 실시하였다. 연구 대상 유역은 임야와 농경지가 주를 이루는 지역으로 농지의 비율이 자자 $0.4\%$와 $35.9\%$인 유역이다. 측정은 건기에서부터 강우기 때까지 각 유역 당 10개의 강우 사상에 대하여 실시하였다. 측정 대상 항목으로는 pH, SS, TCOD, SCOD, BOD, TP, TN, $NH_3-N$, $NO_3-N$, $PO_4-P$, Total coliform, Escherchia Coli를 측정하였고, pollutograph, loadgraph을 작성하였다. 분석 결과 농지의 비율이 큰 유역에서 발생하는 오염부하량이 모든 수질 항목에서 높게 나타났으며, SS, 유기물, 미생물 항목에서 초기강우세척철상(first flush)을 보이고 있었다. 또한 측정 자료에 내한 동계분석결과 SS항목과 유기물 항목은 높은 상관관계를 나타내고 있었으며, 강우에 따른 오염부하량은 누승함수, 2차함수의 형태로 증가하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.74-83
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• 2007

The goal of this study is to establish an integrated watershed hydrologic model for the whole Nakdong River basin whose area is an approximately 24,000 km2. Including a number of watershed elements such as rainfall, runoff, water use, and so on, the proposed model is based on SWAT model, and is used to improve the flow duration curve estimation of ungauged watersheds for Korean Total Maximum Daily Load (TMDL). The model is also used to recognize quantitatively the river flow variation due to water use elements and large dam effluents in the whole watershed. The established combined watershed hydrologic model, SWAT-Nakdong, is used to evaluate the quantified influences of artificial water balance elements, such as a dam and water use in the watershed. We apply two water balance scenarios in this study: the dam scenario considering effluent conditions of 4 large multi-purpose dams, Andong dam, Imha dam, Namgang dam, and Habcheon dam, and the water use scenario considering a water use for stream line and the effluent from a treatment plant. The two scenarios are used to investigate the impacts on TMDL design flow and flow duration of particular locations in Nakdong River main stream. The results from this study will provide the basic guideline for the natural flow restoration in Nakdong River.

• 한국환경복원기술학회지
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• 제10권2호
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• pp.61-70
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• 2007

This study aims to clarify the effect of forest management practices(thinning and pruning) on soil physical properties and water quality to get the fundamental information on the facility of purifying water quality after forestry practices. Rainfall, throughfall, stemflow, soil and stream water were sampled at the study site which consists of Pinus rigida in Jinju National University Experimental Forest for 4 years from Mar. 1, 2002 to Nov. 30, 2006. Averaged tree height of the management site increased by 1.6m, compared to the value of the non-management site in Pinus rigida. Increment of averaged D. B. H. at the management site showed 4.2cm more in Pinus rigida compared with that at non-management sites. Mesopore ratios (pF2.7) and total porosities of A layer soil at the management site increased more than those at the non-management sites in both stands. Otherwise, soil bulk density resulted in being reversely. Water qualities of throughfall, stemflow and buffered soil water were influenced more positively by the management practice. The average electrical conductivity of stream water was $32.9{\mu}S/cm$ within the range of non-polluted stream water.

• 한국환경과학회지
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• 제24권4호
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• pp.425-435
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• 2015

A number of projects for development have been done continuously due to the increase of tourist in Jeju Island. However flood disaster countermeasure due to urbanization is not considered during this development projects. This study is to make basic process for the flood estimation in Han stream of Jeju Island. The variation of stream discharge due the every 5 years' land use change from 1980 to 2005. Data for flood events (rainfall and discharge) were collected for HEC-HMS model. Clark method was used for unit hydrograph analysis. For the estimation of Clark unit hydrograph parameters, Kraven II and Sabol's empirical equations were applied. The peak discharge increased 9.9~33.67% and total discharge amount increased 12.53~30.21%. Also, time of concentration for peak discharge was reduced by 10 minutes for each event.

• 물과 미래
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• 제29권3호
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• pp.153-161
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• 1996

최근에 도시화 된 산본천 유역을 대상으로 한 유출 해석이다. 실측한 각종 자료를 유출해석 모형인 ILLUDAS를 이용하여 도시화에 따른 첨두유량과 총유출량의 연구를 분석하였다. 도시하천에서 첨두유량의 증가는 도시화에 따른 하정비가 가장 큰 영향이 있는 것으로 판단된다. 첨두유량은 강우 지속시간이나 재현기간에 따라 조도계수 n=0,04일 경우에 최대 10%까지, n=0.015일 경우는 7~16%이었으며, 또한 자연하도(n=0.04)에서 계획하도(n=0.015)로 변화하면 첨두유량은 51~158%까지 큰 폭의 증가를 보였다. 일반적으로 호우시 홍수첨두유량은 증가하지만 도시유역의 경우는 배수계통의 정비로 유속이 증가하면서 하천 수위는 오히려 감소하는 것으로 나타났다.

• 한국환경과학회지
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• 제11권10호
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• pp.1075-1080
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• 2002

The hydrological frequency of the flood in July 2000 at Seosi stream basin in Gurye and the bed scour of the stream channel were estimated to investigate the bed scour related with Jeongjang bridge collapse. The storm over the basin in July 2000, 303mm/day was 103year frequency rainfall and the equivalent flood was 2580cms. As the results of 100year and 30year flood application, flood level 30.78~31.38m and mean velocity 3.79~4.03m/s were appeared. And the purification project of Seosi stream increased the velocity of the section near to Jeongjang bridge by the improvement of conveyance at the downstream. The local scour at pier was the major factor of bed scour at Jeongjang bridge site and the total scour at pier No.6 was increased from 2.32m to 2.45m by the purification project.

• International Journal of Contents
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• 제13권4호
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• pp.23-28
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• 2017

Of the total economic loss caused by disasters, 40% are due to floods and floods have a severe impact on human health and life. So, it is important to monitor the water level of a river and to issue a flood warning during unfavorable circumstances. In this paper, we propose a modified error function to improve a hydrological modeling using a multi-layer perceptron (MLP) neural network. When MLP's are trained to minimize the conventional mean-squared error function, the prediction performance is poor because MLP's are highly tunned to training data. Our goal is achieved by preventing overspecialization to training data, which is the main reason for performance degradation for rare or test data. Based on the modified error function, an MLP is trained to predict the water level with rainfall data at upper reaches. Through simulations to predict the water level of Nakdong River near a UNESCO World Heritage Site "Hahoe Village," we verified that the prediction performance of MLP with the modified error function is superior to that with the conventional mean-squared error function, especially maximum error of 40.85cm vs. 55.51cm.

• 한국농공학회논문집
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• 제52권6호
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• pp.135-144
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• 2010

This study was performed to suggest a soil loss reduction skill through estimating soil erosion from a small watershed including each type of sloping agriland by using GEOWEPP model. Experimental watershed at Gangwon province was selected for very typical sloping fields of highland agriculture in Alpine area. Runoff discharge and sediment load, hourly rainfall amount occurred during storm event were gauged, and weather data were obtained from Daegwallyeong meteorological station. The results of GEOWEPP model estimation showed that relative error values for total runoff discharge and sediment load were 3 %, -14.5 % respectively. Based on the result, soil erosion and waterway path map for each hillslope were made to select target hillslope. Several hillslopes of severe soil erosion were analyezed and then the optimal vegetative filter strip construction width and waterway path to plant grass were decided by using GEOWEPP Model.

• 상하수도학회지
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• 제20권6호
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• pp.823-828
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• 2006

For this study, an online particle counter was installed before and after the activated carbon filtration process of D water treatment plant where has advanced water treatment processes, produces average 900,000ton/day of drinking water and supply the produced drinking water to Busan citizens. We collected and analyzed particle count data for about 1 year. We inspected particle breakthrough in three out of sixteen filter processes operated at same conditions, i.e. 5th filter, 6th filter and 7th filter. According to the monitoring results, 6th and 7th filters showed similar results while 5th filter showed different results. When compared seasonal effect, the particle count for dry season was below 10 particles/ml while the particle count for August when monthly average rainfall is over 200mm was much higher than for dry season. In January and August, there was a difference in breakthrough particle size. In January, small particles in 2~3um were mainly detected while in August 10um particles were mainly detected and the size distribution was 40% of total count.

• 한국물환경학회지
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• 제23권4호
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• pp.527-534
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• 2007

To operate scientifical and integrated management of water resources, it needs to identify clearly the quantitative variation and moving pathway of water resources in a basin. Moreover, it needs to also estimate more precisely the amount of runoff generating from the precipitation. Thus, in this study, to carry out more reliable hydrologic analyses, the runoff characteristics according to detailed runoff components and water balance in a basin are analyzed. As a result of yearly water balance analyses, during the period of drought year, the loss is bigger than that of 6-year mean loss and the return flow of groundwater is the most dominant component of runoff. During the period of flood year, the loss is smaller about 4% than that of 6-year mean loss and the subsurface water is the most dominant component of runoff. The loss due to the interception and evapotranspiration for 6-year mean loss is about 53% of the total rainfall, the mean runoff ratio is about 27% and the baseflow is about 22%.