• Title, Summary, Keyword: Hydrological Impact

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A Study of Computer Models Used in Environmental Impact Assessment II : Hydrologic and Hydraulic Models (환경영향평가에 사용되는 컴퓨터 모델에 관한 연구 II : 수리수문 모델)

  • Park, Seok-Soon;Na, Eun-Hye
    • Journal of Environmental Impact Assessment
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    • v.9 no.1
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    • pp.25-37
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    • 2000
  • This paper presents a study of hydrological and hydraulic model applications in environmental impact statements which were submitted during recent years in Korea. In many cases (almost 70 %), the hydrological and hydraulic changes were neglected from the impact identification processes, even if the proposed actions would cause significant impacts on those environmental items. In most cases where the hydrological and hydraulic impacts were predicted, simple equations were used as an impact prediction tool. Computer models were used in very few cases(5%). Even in these few cases, models were improperly applied and thus the predicted impacts would not be reliable. The improper applications and the impact neglections are attributed to the fact that there are no available model application guidelines as well as no requirements by the review agency. The effects of mitigation measures were not analyzed in most cases. Again, these can be attributed to no formal guidelines available for impact predictions until now. A brief guideline is presented in this paper. This study suggested that the model application should be required and guided in detail by the review agency. It is also suggested that the hydrological and hydraulic items shoud be integrated with the water quality predictions in future, since the non-point source pollution runoff is based on the hydrologic phenomena and the water quality reactions on the hydraulic nature.

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Hydrological Model Response to Climate Change Impact Assessments on Water Resources (유출모형이 기후변화 수자원 영향평가에 미치는 영향 분석)

  • Jung, Il-Won;Lee, Byong-Ju;Jun, Tae-Hyun;Bae, Deg-Hyo
    • Journal of Korea Water Resources Association
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    • v.41 no.9
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    • pp.907-917
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    • 2008
  • This study investigates differences in hydrological responses to the climatic scenarios resulting from the use of different three hydrological models, PRMS, SLURP, and SWAT. First, the capability of the three models in simulating the present climate water balance components is evaluated at Andong-dam watershed. And then, the results of the models in simulating the impact using hypothetical climate change scenarios are analyzed and compared. The results show that three models have similar capabilities in simulating observed data. However, greater differences in the model results occur when the models are used to simulate the hydrological impact under hypothetical climate change. According as temperature change grows, the differences between model results is increasing because of differences of the evapotranspiration estimation methods. The results suggest that technique that consider the uncertainty by using different hydrological models will be needed when climate change impact assessment on water resources.

Assessment of Hydrological Impact by Long-Term Land Cover Changes due to Urbanization of Rural Area (농촌유역의 도시화 진전에 따른 수문환경 변화)

  • Lee, Mi-Seon;Park, Geun-Ae;Kwon, Hyung-Joong;Kim, Seong-Joon
    • Journal of Korean Society of Rural Planning
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    • v.11 no.1
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    • pp.17-24
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    • 2005
  • The purpose of this study is to evaluate the hydrological impact due to temporal land cover change by gradual urbanization of Anseong-cheon Gongdo watershed ($371.8km^2$). Land covers of 1981, 1990, 2000 Landsat TM images were classified by maximum likelihood method. The watershed showed a trend that forest & paddy areas decreased about $33km^2$ and $27km^2$, respectively and urban area increased about $11km^2$ during the periods. To identify the impact of streamflow due to urbanization, WMS HEC-1 was used. According to apply Huffs quartile storm events by changing land cover data, peak runoff discharge of each frequency rainfall (50, 100, 500 years) increased about 56, 36, $192m^3/sec$, respectively.

Assessment of Hydrological Impact by Tracing Long-term Land Cover Changes Using Landsat TM Imageries

  • Kim, Seong J.;Park, Geun A.
    • Proceedings of the KSRS Conference
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    • pp.50-52
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    • 2003
  • The purpose of this study is to evaluate the hydrological impact due to temporal land cover changes by gradual urbanization of a watershed. WMS HEC-1 was adopted, and DEM with 200m resolution and hydrologic soil group from 1:50,000 soil map were prepared. Land covers of 1986, 1990, 1994 and 1999 Landsat TM images were classified by maximum likelihood method. By applying the model, watershed average CN value was affected in the order of paddy, forest and urban/residential, respectively.

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Uncertainty Analysis in Hydrologic and Climate Change Impact Assessment in Streamflow of Upper Awash River Basin

  • Birhanu, Dereje;Kim, Hyeonjun;Jang, Cheolhee;Park, Sanghyun
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.327-327
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    • 2019
  • The study will quantify the total uncertainties in streamflow and precipitation projections for Upper Awash River Basin located in central Ethiopia. Three hydrological models (GR4J, CAT, and HBV) will be used to simulate the streamflow considering two emission scenarios, six high-resolution GCMs, and two downscaling methods. The readily available hydrometeorological data will be applied as an input to the three hydrological models and the potential evapotranspiration will be estimated using the Penman-Monteith Method. The SCE-UA algorithm implemented in PEST will be used to calibrate the three hydrological models. The total uncertainty including the incremental uncertainty at each stage (emission scenarios and model) will be presented after assessing a total of 24 (=$2{\times}6{\times}2$) high-resolution precipitation projections and 72 (=$2{\times}6{\times}2{\times}3$) streamflow projections for the study basin. Finally, the primary causes that generate uncertainties in future climate change impact assessments will be identified and a conclusion will be made based on the finding of the study.

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Estimation of evapotranspiration change due to the 2019 April Gangwon-do wildfire using remote-sensing data

  • Kim, JiHyun;Sohn, Soyoung;Kim, Yeonjoo
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.4-4
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    • 2020
  • Three wildfires severely damaged local towns and forests in Gangwon-do, South Korea in 2019 April 4-5. Local hydrological regime could be greatly altered by the wildfires, therefore it is important to assess its damage (e.g. area and severity) and also resultant changes in hydrological fluxes. We retrieved the Normalized-Burned Ratio (NBR) index using remote-sensing data (Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m 8-day surface reflectance data), and delineated the damaged-area based on the difference in the NBR (dNBR) before and after the wildfires. We then estimated changes in the annual evapotranspiration (AET) in 2019 using the MODIS evapotranspiration data (500-m 8-day). It was found that the damaged-area of the three wildfires was 29.50 km^2 in total, which take up 1.00-6.19% area of five catchments. It was estimated that the AET would be decreased as 0.05-1.56% over those five catchments, as compared to the pre-fire AET (2004-2018). The impact of the wildfires on the catchment AET was less severe than expected (i.e. up to 1.56%) mostly because two big wildfires were distributed across two catchments respectively (i.e. four catchments for the two wildfires) and the other wildfire was small and not severe. This study highlights the importance of assessing the area and severity of a wildfire when estimating its impact on the local hydrological cycle.

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Analysis of Hydrological Impact for Long-term Land Cover Change using WMS HEC-l Model in Anseong-Cheon Watershed (WMS HEC-1을 이용한 안성천 유역의 경년 수문 변화 분석)

  • Park, Geun-Ae;Kim, Seong-Joon
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • pp.293-296
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    • 2002
  • The purpose of this study is to evaluate the hydrological impact due to temporal land cover change urbanization of Anseong-cheon watershed $(585.09km^2)$. WMS (Watershed Modeling System) HEC-1 was adopted, and burned DEM with $200{\times}200m$ resolution and soil map reclassified by hydrologic soil groups were prepared. Land cover for 1985, 1990, 1995 and 2000 were classified by maximum likelihood method, using Landsat MSS and TM imageries. Calibration and verification of HEC-1 were conducted using 4 storm events. Peak flow at Pyeong taek station increased $25.9m^3/sec$ during the past 15 years due to paddy and forest decrease. Streamflow impact by just paddy area decrease and forest area decrease were also analysed keeping watershed CN values unchanged of the given year, respectively.

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Evaluation of Hydrological Impacts Caused by Land Use Change (토지이용변화에 따른 수문영향분석)

  • Park, Jin-Yong
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.5
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    • pp.54-66
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    • 2002
  • A grid-based hydrological model, CELTHYM, capable of estimating base flow and surface runoff using only readily available data, was used to assess hydrologic impacts caused by land use change on Little Eagle Creek (LEC) in Central Indiana. Using time periods when land use data are available, the model was calibrated with two years of observed stream flow data, 1983-1984, and verified by comparison of model predictions with observed stream flow data for 1972-1974 and 1990-1992. Stream flow data were separated into direct runoff and base flow using HYSEP (USGS) to estimate the impacts of urbanization on each hydrologic component. Analysis of the ratio between direct runoff and total runoff from simulation results, and the change in these ratios with land use change, shows that the ratio of direct runoff increases proportionally with increasing urban area. The ratio of direct runoff also varies with annual rainfall, with dry year ratios larger than those for wet years shows that urbanization might be more harmful during dry years than abundant rainfall years in terms of water yield and water quality management.

Classification of Groundwater Level Variation Types Near the Excavated Area of the Temporary Gulpocheon Discharge Channel (굴포천 임시방수로 굴착구간 주변의 지하수 수위 변동 유형 분류)

  • Kim, Chang-Hoon;Lee, Su-Gon;Hahn, Jeong-Sang;Kim, Nam-Ju;Jeon, Byeong-Chu
    • The Journal of Engineering Geology
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    • v.24 no.4
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    • pp.631-641
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    • 2014
  • Characteristics of water-level changes in the Temporary Gulpocheon Discharge Channel were identified by observing and analyzing changes in the subterranean water level induced by hydrological stresses the underground aquifer. The subterranean water level refers to the level at which the pressure of subterranean water passing through the corresponding position has an equipotential value that is in equilibrium with the atmospheric pressure at that location. This water level is not fixed but changes in response to hydrological stress. It can be identified by repeatedly measuring the distance from the observation point to the surface of the subterranean water. The subterranean water-level change equation and the variance range of the hydrological curve of subterranean water over 24 hours at the Gimpo-Gimpo National Groundwater Monitoring Network (NGMN) were used as assessment factors. The variance characteristics of the subterranean water at the 18 monitoring system locations were classified into three impact, observational wish, and non-impact. The impact type accounted for 50% of the subterranean water of and accurately reflected the water-level changes due to hydrological stress, showing that distance is the major controlling factor. The observational wish type accounted for 27.8% of the subterranean water, and one of the two assessment factors did not meet the assessment factors. The nonimpact type accounted for 22.2% of the subterranean water. This type satisfied the two assessment factors and represents subterranean water-level changes response to precipitation.

The Analysis of Hydrological Property with Curved-channel Type (하도만곡형상에 따른 수리특성분석)

  • Ahn, Seung-Seop;Lee, Sang-Il;Park, Dong-Il;Kim, Wi-Seok
    • Journal of Environmental Science International
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    • v.20 no.10
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    • pp.1309-1317
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    • 2011
  • This study selected 6 river reach, which have various curved-channel, included in an object of study as making the Nakdong River, which is a real nature river, as a point of an object of study by using SMS RMA-2 model, a 2D numerical analysis model, and applied project flood and analyzed and examined characteristic of hydrological property and super-elevation, which includes characteristic of the velocity of a moving fluid. As a result, in a river reach, whose width is wide, angle of curved-channel has impact on the velocity of a moving fluid of inside of curved-channel and in a river reach, whose width is narrow, the radius of curvature and width of the river have impact on the velocity of a moving fluid of inside of curved-channel. Also it found out that the ratio of reduction in water-level of inside of curved-channel is more bigger than ratio of increasing in water-level of outside of curved-channel when project flood is increasing and angle of curve is increasing. Based on this, this study would be used as a expectation of danger and preliminary data in planning real river or a business, that creates an environment.