• 한국농공학회논문집
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• 제49권6호
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• pp.3-9
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• 2007

Stream flow and water quality were measured and analyzed with respect to flow-weighted mean concentrations (FWMCs) of 21 rainfall events from a forested watershed (Forest Research Watershed: FRW) and two mixed watersheds of agriculture and forest (YuPo-Ri Watershed: YPW and WolGog-ri Watershed: WGW) located in the middle of the North Han River basin. The monitoring of each watershed was one year and conducted between 2004 and 2006. YPW showed more intensive agricultural practices than WGW where traditional practices were common. The average of the 21 FWMCs were in the order of YPF>WGW>FRW and were significantly different from each other at the level of 0.05. It was shown that the land use with intensive agricultural practices produced and discharged more NPS pollutants than that with traditional practices and forest. Specially, SS concentrations from the mixed watersheds were significantly higher than those from FRW. Influencing factors on runoff were analyzed rainfall and watershed area. And rainfall intensity was greater impact on runoff than daily rainfall. Measured water quality indices were shown positive correlations among them in general. However, no significant correlation was shown between COD and nutrients(T-N and T-P).

• 한국환경과학회지
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• 제28권2호
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• pp.259-266
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• 2019

Two main sources of data, meteorological data and land surface characteristics, are essential to effectively run a distributed rainfall-runoff model. The specification and averaging of the land surface characteristics in a suitable way is crucial to obtaining accurate runoff output. Recent advances in remote sensing techniques are often being used to derive better representations of these land surface characteristics. Due to the mismatch in scale between digital land cover maps and numerical grid sizes, issues related to upscaling or downscaling occur regularly. A specific method is typically selected to average and represent the land surface characteristics. This paper examines the amount of flooding by applying the FLO-2D routing model, where vegetation heterogeneity is manipulated using the Manning's roughness coefficient. Three different upscaling methods, arithmetic, dominant, and aggregation, were tested. To investigate further, the rainfall-runoff model with FLO-2D was facilitated in Yongdam catchment and heavy rainfall events during wet season were selected. The results show aggregation method provides better results, in terms of the amount of peak flow and the relative time taken to achieve it. These rwsults suggest that the aggregation method, which is a reasonably realistic description of area-averaged vegetation nature and characteristics, is more likely to occur in reality.

• 한국수자원학회논문집
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• 제48권5호
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• pp.393-407
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• 2015

본 연구에서는 충주댐 유역을 대상으로 레이더 자료를 이용하여 호우의 산지효과 특성을 분석하였다. 먼저 적절한 무강우 기간과 절단값을 결정하여 독립호우사상을 선정하였다. 이러한 독립호우사상으로부터 산지효과의 발현 여부를 판단할 주요호우사상을 선정하였다. 또 레이더 자료를 이용하여 전체 기간과 호우중심 기간의 평균반사도를 산정하고, 산지 부근의 반사도와 평균반사도를 비교하여 반사도의 변화를 분석하였다. 아울러 본 연구에서는 호우의 특성인자를 선정하고 로지스틱 회귀분석을 수행하여 충주댐 유역 호우의 산지효과 발현 조건을 확인하였다. 그 결과를 정리하면 다음과 같다. 먼저 산악 지역을 통과하는 호우의 이동선상에서의 반사도 변화를 검토한 결과 호우의 시작 지점에 비하여 산악 지역에서의 반사도가 증가한 것으로 확인되었다. 둘째, 산지효과 발현 조건을 탐색하기 위해 로지스틱 회귀분석을 수행한 결과 충주댐 유역에서는 임계값이 호우의 이동속도 4km/hr, 접근각도 $90^{\circ}{\pm}5^{\circ}$, 강우강도 4mm/hr인 경우에 산지효과의 발현 여부 적중률이 가장 높은 것으로 확인되었다.

• 한국농공학회논문집
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• 제62권4호
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• pp.13-22
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• 2020

The Doam Lake watershed has a significant impact on the downstream water system due to nutrients and sediment outflow during rainfall caused by steep slopes, soil losses, and fertilization. These non-point sources are unclear in the discharge area and are affected by land use patterns, soil characteristics, and topographical features of the watershed. Therefore, this study conducted rainfall monitoring from July to October 2019 in Songcheon upstream of the Doam Lake watershed, one of the non-point pollution source management areas. Then, after analyzing rainfall runoff, Event Mean Concentration (EMC) and Mass First Flush ratio (MFFn) were calculated to compare and analyze the characteristics of rainfall and the non-point pollutant discharge. As a result of the analysis, it showed various non-point pollutant emission characteristics for each rainfall event. In addition, the concentration of EMC and the MFFn were affected by the average rainfall intensity and the maximum rainfall intensity, and were not significantly affected by the number of antecedent drying days. In the future, it is expected that effective non-point source reduction measures and management measures according to rainfall intensity through continuous monitoring and analysis will be needed.

• 한국수자원학회논문집
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• 제53권8호
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• pp.583-595
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• 2020

본 연구에서는 청계천 효자배수분구 유역을 대상으로 RCP 시나리오를 이용하여 Historical 강수량 및 5개의 GCMs 모델로 부터 산정된 Future 강수량과의 변화를 분석하였다. 각 GCMs 모델별 Historical 대비 Future 연 평균 강수량은 최소 35.30 mm에서 최대 208.65 mm 증가하였다. 그리고 Historical 대비 Future 변화율은 1.73%~16.84% 증가하였다. SWMM 모형을 이용하여 투수성포장, 침투도랑, 옥상녹화 3가지의 LID 요소기술을 이용하였다. 그리고 LID 요소기술별 적용된 가중치 변화에 따른 유출량을 분석하였다. 그 결과 각 GCMs 모델별 차이는 있으나 최소 2.58%, 최대 28.78% 유출량이 증가하였다. 그러나 투수성포장 및 침투도랑의 단일 적용시 INM-CM4와 MRI-CGCM3 모델에서 Historical 유출량 대비 각각 3.48%와 2.74%, 8.04%와 7.16% 감소되었다. 또한 두 가지의 LID 요소기술을 조합한 경우에도 유출량이 2.74%와 2.89%, 7.16%와 7.31% 감소되었다. 이것은 기존 Historical의 유출량보다 적거나 유사한 수준인 것으로 분석되었다. LID 요소기술의 적용 결과, 옥상녹화가 도심유역 면적의 1/3정도 적용되는 것이 유출량에 대한 지체시간을 확보하는데 가장 효과적인 것으로 나타났다. 또한 구도심 지역에 LID 기법을 적용할 경우 경제적 비용, 유지관리, 도심경관의 순서로 우선순위를 고려하는 것이 바람직하다.

• 한국농공학회논문집
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• 제65권3호
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• pp.69-82
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• 2023

Representative meteorological data of the rural water district, which is the spatial unit of the study, was produced using the grid-based national standard RCP scenario rainfall data provided by the Korea Meteorological Administration. The retrospective reproducibility of the climate model scenario data was analyzed, and the change in climate characteristics in the water district unit for the future period was presented. Finally the data characteristics and differences of each meteorological element according to various spatial resolution conversion and post-processing methods were examined. As a main result, overall, the distribution of average precipitation and R95p of the grid data, has reasonable reproducibility compared to the ASOS observation, but the maximum daily rainfall tends to be distributed low nationwide. The number of rainfall days tends to be higher than the station-based observation, and this is because the grid data is generally calculated using the area average concept of representative rainfall data for each grid. In addition, in the case of coastal regions, there is a problem that administrative districts of islands and rural water districts do not match. and In the case of water districts that include mountainous areas, such as Jeju, there was a large difference in the results depending on whether or not high rainfall in the mountainous areas was reflected. The results of this study are expected to be used as foundation for selecting data processing methods when constructing future meteorological data for rural water districts for future agricutural water management plans and climate change vulnerability assessments.

• 대한토목학회논문집
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• 제33권1호
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• pp.171-179
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• 2013

최근 우리나라에서는 2002년 태풍 루사, 2003년 태풍 매미, 2006년 태풍 에위니아와 집중호우로 인하여 산지가 약 90%를 차지하고 있는 강원지역의 주택, 도로, 농지가 큰 피해를 입었다. 이로 인한 경제적 손실과 사망자의 대부분은 홍수와 토석류가 발생된 산지 계곡부와 시내에 집중되었다. 본 연구에서는 기존에 강원지역에서 발생된 토석류 발생지에 대한 현장조사를 실시하여 총 180개소의 토석류에 대한 데이터베이스를 구축하였다. 구축된 자료에 대한 분석결과, 강원지역에서 발생된 토석류는 대부분 소규모 사면파괴로부터 시작하였으며, $34.3^{\circ}$의 비교적 가파른 경사에서 발생하여 평균 $18.1^{\circ}$ 정도의 완만한 경사를 따라 420 m 정도의 비교적 짧은 거리를 이동하는 것으로 나타났다. 또한, 토석류 발생 당일의 강우도 중요하지만 발생 이전의 장기강우가 토석류 발생과 밀접한 관련이 있는 것으로 나타났다.

• 대기
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• 제32권2호
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• pp.119-133
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• 2022

From 2015 to 2021, high-concentration fine dust episodes with a daily average PM_2.5 concentration of 50 ㎍ m^-3 or higher were selected and classified into 3 types [long range transport (LRT), mixed (MIX) and Local emission and stagnant (LES)] using synoptic chart and backward trajectory analysis. And relationships between the fine particle data (PM_2.5 and PM₁₀ concentration and PM_2.5/PM₁₀ ratio) and meteorological data (PBLH, Ta, WS, U-wind, and Rainfall) were analyzed using hourly observation for the classification episodes on the Korean Peninsula and the Seoul metropolitan area (SMA). In LRT, relatively large particles such as dust are usually included, and in LES, fine particle is abundant. In the Korean peninsula, the rainfall was relatively increased centered on the middle and western coasts in MIX and LES. In the SMA, wind speed was rather strong in LRT and weak in LES. In LRT, rainfall was centered in Seoul, and in MIX and LES, rainfall appeared around Seoul. However, when the dust cases were excluded, the difference between the LRT and other types of air quality was decreased, but the meteorological variables (Ta, RH, Pa, PBLH, etc.) were further strengthened. In the case of the Korean Peninsula, it is difficult to find a clear relationship because regional influences (topographical elevation, cities and coasts, etc.) are complexly included in a rather wide area. In the SMA, it is analyzed that the effects of urbanization such as the urban heat island centered on Seoul coincide with the sea and land winds, resulting in a combination of high concentrations and meteorological phenomena.

• 한국농공학회논문집
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• 제48권7호
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• pp.3-14
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• 2006

The objective of this study was to develop a GIS-based decision support system (GIS-USLE system) to estimate soil erosion and evaluate its effect on concentrated upland plots in Godang district, Korea. This system was developed for the ArcView environment using A VENUE script. Three modules were used in the GIS-USLE system, namely pre-processing, the USLE factors calculator module, and post-processing. This system benefits from a user friendly environment that allows users with limited computer knowledge to use it. This system was applied to 1,285 individual upland plots ranging from 0.005 to 1.347 ha in size with an average slope steepness of 14 %. The rainfall distributions were estimated using the three methods, namely Mononobe and Yen-Chow with Triangle and with Trapezoid type, and then used to calculate the rainfall erosivity factor. The soil erosion amounts from the 1,285 individual plots in the study area by 2 year return period with a 24h maximum rainfall amount of 154.6 mm were estimated at 5 tons/ha on average. Slope appeared to be the most important factor affecting soil erosion estimation, as expected. The prototype model was applied to the project area, and the results appeared to support the practical applications. By examining many fields simultaneously, this system can easily provide fast estimation of soil erosion and thus reveal the spatial pattern of erosion from fields in a region. This study will help estimate and evaluate soil erosion in concentrated upland districts and identify the best management practices.

• 한국환경과학회지
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• 제19권6호
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• pp.747-753
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• 2010

It follows in quality and sewage exclusion method of the investigation objective sector and the Combined Sewer Overflows which is suitable in regional characteristics and the confluence area against the rainfall initially a flow and the medulla and measurement - it analyzes the initial rainfall outflow possibility control plan which is suitable in the domestic actual condition and it proposes the monitor ring plan for the long-term flow and pollution load data accumulation. From the research which it sees the Infiltration water/Influent water and CSOs investigation it passes by the phase of hazard chain and Namwon right time 4 it does not hold reverse under selecting, Measurement it used the hazard automatic flow joint seal Sigma 910 machine and in case 15 minute interval of the I/I, it measured a flow at case 5, 15 minute standing of the CSOs. The water quality investigation for the water leakage investigation of the I/I and the sewage from the point which is identical with flow measurement during on-the-spot inspection duration against 6 items which include the BOD sampling and an analysis, when the rainfall analysis for CSOs fundamental investigation analyzed against 18 items which include the BOD sampling. Consequently, for the optimum interpretation invasion water / inflow water of the this investigation area day average the lowest flow - water quality assessment veterinarian optimum interpretation hazard average per day - lowest flow - it averages a medulla evaluation law department one lowest flow evaluation technique and it selects, it presentation collectively from here it gets, position result with base flow analysis of invasion water / inflow water.