• Title/Summary/Keyword: rainfall-runoff simulator

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The Study on Development and Verification of Rainfall-Runoff Simulator for LID Technology Verification (LID 기술의 효율성 검증을 위한 강우-유출 모의장치 개발 및 검증실험에 관한 연구)

  • Jang, Young Su;Kim, Mi Eun;Baek, Jong Seok;Shin, Hyun Suk
    • Journal of Korea Water Resources Association
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    • v.47 no.6
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    • pp.513-522
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    • 2014
  • Climate change and urbanization have affected a increase of peak discharge and water pollution etc. In a view of these aspects, the LID(Low Impact Development) technology has been highlighted as one of adjustable control measures to mimic predevelopment hydrologic condition. Many LID technologies have developed, but there is a lack of studies with verification of LID technology efficiency. Therefore this study developed a rainfall-runoff simulator could be possible to verify LID technology efficiency. Using this simulator, this study has experimented the rainfall verification through the rainfall distribution experiment and the experiment to show the relation between inflow and effective rainfall in order to sprinkle the equal rainfall in each unit bed. As a result, the study defined the relation between allowable discharge range and RPM by nozzle types and verified the hydrologic cycle such as the relation between infiltration rate, surface runoff and subsurface runoff at pervious area and impervious area through the rainfall-runoff experiment.

Simulation of generable muddy water quantity and pollutant loads in sloping field using artificial rainfall simulator (실내인공강우기를 이용한 경사지 밭의 토양유실량과 오염부하 모의)

  • Shin, Min-Hwan;Choi, Yong-Hun;Seo, Ji-Yeon;Lee, Jae-Woon;Choi, Joong-Dae
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.986-990
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    • 2009
  • Using artificial rainfall simulator, the soil loss, which is deemed as most cause of muddy water problem among Non-point source(NPS) pollutant, was studied by the analysis of direct runoff flow, groundwater runoff, and groundwater storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared boxes which are 5%, 10%, and 20% sloped respectively. Also the direct runoff volume from straw covered surface boxes were much lower than bared surface boxes. It's deemed as that the infiltration capacity of straw covered surface boxes were increased, because the surface sealing by fine material of soil surface didn't occurred due to the straw covering. Under the same rainfall intensity and slope condition, 2.4 ${\sim}$ 8.2 times of sediment yield were occurred from bared surface boxes more than straw covered surface boxes. The volume of infiltrated were increased due to straw cover, the direct runoff flow were decreased with decreasing of tractive force in surface. To understand of relationship the rate of direct runoff flow, groundwater runoff, and groundwater storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, expect between the rate of groundwater storage and rainfall intensity.

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Analysis of Rainfall Runoff Delay Effect of Vegetation Unit-type LID System through Rainfall Simulator-based Probable Rainfall Recreation (인공강우기 기반 확률강우재현을 통한 식생유니트형 LID시스템의 우수유출지연 효과분석)

  • Kim, Tae-Han;Park, Jeong-Hyun;Choi, Boo-Hun
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.22 no.6
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    • pp.115-124
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    • 2019
  • In a climate change environment where heat damage and drought occur during a rainy season such as in 2018, a vegetation-based LID system that enables disaster prevention as well as environment improvement is suggested in lieu of an installation-type LID system that is limited to the prevention of floods. However, the quantification of its performance as against construction cost is limited. This study aims to present an experiment environment and evaluation method on quantitative performance, which is required in order to disseminate the vegetation-based LID system. To this end, a 3rd quartile huff time distribution mass curve was generated for 20-year frequency, 60-minute probable rainfall of 68mm/hr in Cheonan, and effluent was analyzed by recreating artificial rainfall. In order to assess the reliability of the rainfall event simulator, 10 repeat tests were conducted at one-minute intervals for 20 minutes with minimum rainfall intensity of 22.29mm/hr and the maximum rainfall intensity of 140.69mm/hr from the calculated probable rainfall. Effective rainfall as against influent flow was 21.83mm/hr (sd=0.17~1.36, n=20) on average at the minimum rainfall intensity and 142.27mm/hr (sd=1.02~3.25, n=20) on average at the maximum rainfall intensity. In artificial rainfall recreation experiments repeated for three times, the most frequent quartile was found to be the third quartile, which is around 40 minutes after beginning the experiment. The peak flow was observed 70 minutes after beginning the experiment in the experiment zone and after 50 minutes in the control zone. While the control zone recorded the maximum runoff intensity of 2.26mm/min(sd=0.25) 50 minutes after beginning the experiment, the experiment zone recorded the maximum runoff intensity of 0.77mm/min (sd=0.15) 70 minutes after beginning the experiment, which is 20 minutes later than the control zone. Also, the maximum runoff intensity of the experiment zone was 79.6% lower than that of the control zone, which confirmed that vegetation unit-type LID system had rainfall runoff reduction and delay effects. Based on the above findings, the reliability of a lab-level rainfall simulator for monitoring the vegetation-based LID system was reviewed, and maximum runoff intensity reduction and runoff time delay were confirmed. As a result, the study presented a performance evaluation method that can be applied to the pre-design of the vegetation-based LID system for rainfall events on a location before construction.

Simulation of Field Soil Loss by Artificial Rainfall Simulator - By Varing Rainfall Intensity, Surface Condition and Slope - (인공강우기에 의한 시험포장 토양유실량 모의 - 강우강도, 지표면 및 경사조건 변화 -)

  • Shin, Minhwan;Won, Chul-hee;Choi, Yong-hun;Seo, Jiyeon;Lee, Jaewoon;Lim, KyoungJae;Choi, Joong-dae
    • Journal of Korean Society on Water Environment
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    • v.25 no.5
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    • pp.785-791
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    • 2009
  • Using artificial rainfall simulator, the soil loss, which is deemed as the most cause of muddy water problem among Non-point source (NPS) pollutant, was studied by the analysis of direct runoff, groundwater discharge, and soil water storage properties concerned with rainfall intensity, slope of area, and land cover. The direct runoff showed increasing tendency in both straw covered and bared soil as slope increases from 5% to 20%. The direct runoff volume from straw covered surface were much lower than bared surface. The infiltration capacity of straw covered surface increased, because the surface sealing by fine material of soil surface didn't occur due to the straw covering. Under the same rainfall intensity and slope condition, 2.4~8.2 times of sediment yield were occurred from bared surface more than straw covered surface. The volume of infiltration increased due to straw cover and the direct runoff flow decreased with decrease of tractive force in surface. To understand the relationship of the rate of direct runoff, groundwater discharge, and soil water storage by the rainfall intensity, slope, and land cover, the statistical test was performed. It shows good relationship between most of factors, except between the rate of groundwater storage and rainfall intensity.

Simulation of Generable Nutritive Salts by Artificial Rainfall Simulator in field - By Varying Amount of Fertilization and Slope - (인공강우기에 의한 밭에서의 영양물질 배출특성 모의 - 시비량 및 경사도 변화 -)

  • Shin, Min-Hwan;Won, Chul-Hee;Choi, Yong-Hun;Seo, Ji-Yeon;Choi, Joong-Dae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.3
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    • pp.31-38
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    • 2010
  • Various fundamental and practical theories and technologies are needed for the development of Best Management Practices (BMPs) to manage the problems. The objectives of this paper was to investigate the effect of fertilizer and Non-point suource (NPS) pollution discharges from the field. The effect of fertilizer application was measured with respect to 10 % and 20 % slopes, respectively, using artificial rainfall simulator. The effect of fertilizer application on runoff was not significant because the effect of slope and rainfall intensity were overwhelmed. Runoff from 20 % plots was 21 % larger than that from 10 % plots. While groundwater discharge from 10 % plots was about 70 % larger than that from 20 % plots. It was concluded that runoff and groundwater discharge were largely affected by slope. T-N concentration in groundwater was much higher than that in runoff for both 10 % and 20 % plots. While T-P concentration in groundwater was lower than that in runoff. It explained that T-N moved well through soil pores without adsorption and other chemical reactions but T-P was well adsorbed on the surface of soil particles.

Surface Cover Application for Reduction of Runoff and Sediment Discharge from Sloping Fields (경사지 밭에서 발생하는 토양유실 저감을 위한 피복재 적용)

  • Shin, Min-Hwan;Won, Chul-Hee;Park, Woon-Ji;Choi, Young-Hun;Shin, Jae-Young;Lim, Kyoung-Jae;Choi, Joong-Dae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.53 no.6
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    • pp.129-136
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    • 2011
  • To measure effects of surface cover on runoff and sediment discharge reduction using rainfall simulator, four(5 m${\times}$30 m scale) plot experiments were conducted in this study. Surface covers made with straw mat, Polyacrylamide (PAM), chaff, and sawdust were simulated 4 times under 31.1~44.4 mm/hr rainfall intensities. Compared with results from control plot, the time of runoff generation is delayed and outflow volume decreased with surface cover. Effects on runoff reduction of straw mat, PAM, sawdust and chaff ranged 4.7~81.5 % and runoff rate reduced by 6.5~76.1 % respectively, when compared with those from control plot. The percentage of decrease in sediment discharge were 99.7~99.8 % from straw mat+sawdust+PAM plots, 85.9~95.6 % from straw mat+PAM plots, and 98.5~99.4 % from straw mat+chaff+PAM plots. The runoff, sediment discharge, and SS concentration reduction efficiencies of the cover materials were outstanding when compared to control plot. It was analyzed that reduction of runoff and sediment discharge were mainly contributed by decrease in rainfall energy impact and flow velocity and increase of infiltration due to the surface cover materials. The results could be used as a base for the development of best management practices (BMPs) to reduce runoff, sediment discharge from sloping field.

EFFCTS OF TILLAGE SYSTEMS ON THE QUALITY OF RUNOFF FROM SLUDGE-AMENDED SOILS

  • Mostaghimi, Saied;Bruggeman, Adriana C.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.984-993
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    • 1993
  • land application of sewage sludge requires careful monitoring because of its potential for contamination of surface water and groundwater. A rainfall simulator was used to investigated the effects of freshly applied sludge on runoff of sediment and nutrients from agricultural crop lands. Rain was applied to 16 experimental field plots. A three run sequence was used to simulate different initial moisture conditions. Runoff, sediment and nutrient losses were monitored at the base of each plot during the simulated rainfall events. Sludge was surface applied and incorporated at conventionally -tilled plots and surface applied at no-till plots, at rates of 0, 75, 150 kg-N/ha. No-till practices greatly reduced runoff, sediment , and nutrient losses form the sludge treated plots, relative to the conventional tillage practices. Incorporation of the sludge was effective in reducing nutrient yields at the conventionally-tilled plots. This effect was more pronounced during the third rain torm, with wet initial conditions. Peak loadings of nutrients appeared during the rainstorm with wet initial conditions.

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Interaction between Raindrops Splash and Sheet Flow in Interrill Erosion of Steep Hillslopes (급경사면의 세류간 침식에서 빗물튀김과 면상흐름의 상호작용)

  • Nam, Myeong Jun;Park, Sang Deog;Lee, Seung Kyu;Shin, Seung Sook
    • Journal of Korea Water Resources Association
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    • v.48 no.7
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    • pp.595-604
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    • 2015
  • Interrill erosion by the rainfall is divided into a detachment of soil particles by raindrop splash when raindrops having kinetic energy strike on the surface soil and a sediment transport by sheet flow of surface runoff. Rainfall kinetic energy is widely used as an indicator expressing the potential ability to separate the soil particles from soil mass. In this study, the soil erosion experiments of rainfall simulation were operated to evaluate the effects of rainfall kinetic energy on interrill erosion as using the strip cover to control raindrop impact. The kinetic energy from rainfall simulator was 0.58 times to that of natural rainfall. Surface runoff and subsurface runoff increased and decreased respectively with increase of rainfall intensity. Surface runoff discharge from plots of non-cover was 1.82 times more than that from plots with cover. The rainfall kinetic energy influenced on the starting time of surface and subsurface runoff. Soil erosion quantity greatly varied according to existence of the surface cover that can intercept rainfall energy. Sediment yields by the interaction between raindrop splash and sheet flow increased 3.6~5.9 times and the increase rates of those decreased with rainfall intensity. As a results from analysis of relationship between stream power and sediment yields, rainfall kinetic energy increased the transport capacity according to increase of surface runoff as well as the detachment of soil particles by raindrop splash.

A Study on the Effectiveness Verification of Hydrological Cycle of Pervious Pavement using LID Simulator (LID 효율성 검증기기를 이용한 투수성 블록의 수문순환 효율성 검증에 관한 연구)

  • Kim, Mi Eun;Jang, Young Su;Nam, Chil Ho;Shin, Hyun Suk
    • Journal of Korea Water Resources Association
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    • v.48 no.5
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    • pp.321-330
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    • 2015
  • In recent, the impacts of urbanization on hydrology and water quality can be minimized with the use of Low Impact Development (LID) practices in urban areas. But, there are no ways to verify or to show the quantitative effectiveness with LID practices. This study designed and developed to perform experiments in natural or artificial representation of hydrological cycle, which is called rainfall-runoff simulator to be able to quantify factors in hydrological system. This simulator was applied to a pervious pavement block. The study conducted analysis of effectiveness for a pervious pavement block by comparing the results with a general pavement block. The result from the pervious pavement block showed remarkably reduction effect on surface runoff with increase of rainfall intensity and more duration time. Also, the simulator was possible to control no surface runoff by a rainfall intensity at 50 mm/hr for an hour. The research indicated possibility and effectiveness for LID practices. This might be widely available to apply to LID practices verification. Therefore, the study is possible to make use of practical standards on fundamental studies.

Characteristics of Surface Flow on the Forest Fire Sites by Using Rainfall Simulator (인공강우장치를 이용한 산불발생지의 지표유출 특성에 관한 연구)

  • Lee, Heon Ho;Joo, Jae duk
    • Journal of Korean Society of Forest Science
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    • v.95 no.3
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    • pp.350-357
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    • 2006
  • For the purpose of this study, the characteristics of surface flow through the survey of rainfall intensity and degree of slope on fire sites by using rainfall simulator was examined and analysed. And also the relationship between the amount of surface flow and rainfall intensity, degree of slope and elapsed year after forest fire occurrence influencing on the surface flow were analysed. The results obtained were as follows: 1. The amount of surface flow by year of occurrence of forest fire was increased 2,2 to 3,2 times as rainfall intensity was increased by 30 mm/hr, and 1.5 to 1.9 times as degree of slope was increased by $10^{\circ}$, 2, Even though ground vegetation in forest fire sites was recovered more than 80%, the amount of surface flow in initial rainfall was relatively much and it seemed that vegetation didn't play substantial roles in reducing runoff. 3, The amount of surface flow by rainfall intensity and degree of slope in accordance with elapsed years after forest fire was reduced 22,3% to 41,8% in three years after fire as compared to the first year of fire occurrence. The amount of surface flow were significantly differentiated by rainfall intensity and degree of slope in the first year of fire occurrence and the difference were gradually reduced afterwards. 4. In the analysis on influences of each factors on the amount of surface flow on forest fire sites, the amount of surface flow was significant differences in major impacts of each rainfall intensity, degree of slope and elapsed year after fire and interaction of rainfall intensity ${\times}$ degree of slope and rainfall intensity ${\times}$ elapsed year after fire, but no differences were observed in interaction of degree of slope ${\times}$ elapsed year after tire and rainfall intensity ${\times}$ degree of slope ${\times}$ elapsed year after tire. Rainfall intensity was the most affecting factor on the amount of surface flow and followed by degree of slope and elapsed year after fire.