• Title/Summary/Keyword: NRCS

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Groundwater Level Estimation on a Slope by NRCS model (NRCS 침투모형에 의한 경사진 사면의 지하수위 평가)

  • Moon, Young-Il;Shin, Dong-Jun;Oh, Tae-Suk;Lee, Su-Gon
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.553-556
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    • 2008
  • Slope-related disasters have been occurred in July and September due to the typhoon and concentrated precipitation. It is shown that rainfall is the most important factor which leads to slope-related disasters in Korea. In this paper, slope analysis was applied by rainfall intensity as a rain factor and was assumed that all rainfall would be infiltrated on the slope. Also, groundwater level on a slope was estimated by using SEEP/W program according to infiltration. Where, amount of Infiltration can be calculated by using NRCS model. Finally, safety factor on a slope was invested by groundwater level.

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Comparative Analysis of Estimation Methods for Basin Averaged Effective Rainfall Using NRCS-CN Method (NRCS-CN 방법을 이용한 유역평균 유효우량 산정기법의 비교·분석)

  • Moon, Geon-Woo;Yoo, Ji-Young;Ahn, Jae-Hyun;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.2
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    • pp.493-503
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    • 2014
  • The NRCS-CN method is generally applied for estimating effective rainfalls in practice, in which the basin-averaged CN is normally used. In order to develop a more appropriate method for estimating effective rainfalls in a basin, this study compared estimated effective rainfalls from two distinct methods with the observed direct runoff. The first method is to estimate the basin-representative effective rainfall using the basin-averaged CN (hereafter, effective rainfall I), whereas the second method to estimate the basin-averaged effective rainfall through areal-averaging sub-area effective rainfalls corresponding to the soil type and landuse type (hereafter, effective rainfall II). The overall results indicated that the effective rainfall II was higher than the effective rainfall I and closer to the observed direct runoff. The study also performed error analyses to verify that the effective rainfall II can be applied in practice in a basin as more accurate estimate of basin-representative effective rainfall.

Runoff Estimation with Consideration of Land-Use Distribution (토지이용 분포를 고려한 유출량 산정기법)

  • Son, Kwang-Ik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.1
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    • pp.97-102
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    • 2008
  • The Natural Resource Conservation Service Curve Number(NRCS-CN) method is one of the widely used methods for computation of runoff from a basin. However, NRCS-CN method has a weak point in that the spatial land use distribution characteristics are ignored by using area-weighted CN value. This study developed a runoff estimation algorithm which can reflect the spatial land-use distribution. The algorithm consists of Moglen's theory and a developed flow accumulation estimation program in FORTRAN. Comparisons between the results from area-weighted CN method and this study showed reasonably good agreement with measured data of experimental watersheds. The developed program predicted lower runoff than the conventional NRCS-CN method. As a conclusion, this study proposes a new design direction which can simulate real runoff phenomena. And the developed program could be applied into runoff minimization design for a basin development.

Re-establishing the Antecedent Moisture Condition of NRCS-CN Method Considering Rainfall-Runoff Characteristics in Watershed Based on Antecedent 5-Day Rainfall (유역의 강우-유출 특성을 고려한 NRCS-CN 방법의 선행토양함수조건의 재설정: 선행5일강우량을 기준으로)

  • Yoo, Ji-Young;Moon, Geon-Woo;Ahn, Jae-Hyun;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.3
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    • pp.849-858
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    • 2014
  • The mount of antecedent 5-day rainfall (P5) is usually used to determine the antecedent soil moisture condition for estimating effective rainfall using the NRCS-CN method. In order to re-establish the threshold of P5 considering basin characteristics, this study investigated the sensitivity of the threshold of P5 to effective rainfall by comparing the corresponding observed direct runoff. The overall results indicate that the direct runoff estimated using the re-establihed threshold of P5 has smaller mean error (RMSE of 27.3 mm) than those using the conventional threshold (RMSE of 35.2 mm). In addition, after evaluating the effectiveness of threshold of P5 using the improvement index, the threshold re-established in this study improved the ability to estimate the direct runoff by 30% on average. This study also suggested to employ regression models using topographic indices to re-establish the threshold for ungauged basins. When using the re-established threshold from the regression model, the RMSE decreased ranging from 0.4 mm to 15.1 mm and the efficiency index of Nash and Sutcliffe increased up to 0.33.

Comparison of the Chemical Compositions of Korean and Chinese Safflower (Carthamus tinctorious L.) Seed (한국산과 중국산 홍화종실의 화학적 성분 비교)

  • Kim, Jun-Han;Kwak, Don-Yun;Choi, Myung-Sook;Moon, Kwang-Deog
    • Korean Journal of Food Science and Technology
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    • v.31 no.4
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    • pp.912-918
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    • 1999
  • The chemical compositions of korean and Chinese safflower (Carthamus tinctorious L.) seed were compared in this study. The proximate compositions were 0.73 and 0.05% of moisture, 19.74 and 18.82% of crude protein, 15.47 and 14.61% of crude fat, 3.78 and 3.87% of crude ash, 14.53 and 10.46% of crude fiber, 46.49 and 52.23% of N-free extracts in the non-roasted safflower seed (NRS) and roasted safflower seed (RS), respectively. Crude fat contents in non-roasted chinese safflower seed (NRCS) and roasted chinese safflower seed (RCS) were 33.30 and 31.22%, which were higher than those of NRS and RS. Unsaturated fatty acid in NRS was 83.2% and 90.9% in NRCS. Linoleic acid was the most predominant fatty acid in NRS (74.0%) and NRCS (74.2%). Sucrose (216.5 mg/100 g) and raffinose (117.5 mg/100 g) were major free sugars in NRS, but sucrose, glucose, fructose and raffinose were in NRCS. Glutamic acid, aspatic acid and arginine were major in total amino acids. 24 kinds of free amino acid were detected in NRS and 11 kinds in RS. Total essential amino acid in NRS ($28.0\;{\mu}g/100\;g$) was higher than that in NRCS ($9.2\;{\mu}g/100\;g$). The organic acids in safflower seed were composed of formic acid, succinic acid, malic acid, oxalic acid and fumaric acid. The content of vitamin E $({\alpha}-tocopherol)$ in NRS and NRCS were 10.5 mg/100 g, 6.2 mg/100 g, NRCS and RCS were 12.8 mg/100 g, 9.4 mg/100 g, respectively. Total carotenoid content in NRCS was $452.0\;{\mu}g/100\;g$ and it was higher than in NRS. The major minerals of safflower seed were K, P, Ca, Mg.

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Estimation of Polarization Ratio for Sea Surface Wind Retrieval from SIR-C SAR Data

  • Kim, Tae-Sung;Park, Kyung-Ae
    • Korean Journal of Remote Sensing
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    • v.27 no.6
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    • pp.729-741
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    • 2011
  • Wind speeds have long been estimated from C-band VV-polarized SAR data by using the CMOD algorithms such as CMOD4, CMOD5, and CMOD_IFR2. Some SAR data with HH-polarization without any observations in VV-polarization mode should be converted to VV-polarized value in order to use the previous algorithms based on VV-polarized observation. To satisfy the necessity of polarization ratio (PR) for the conversion, we retrieved the conversion parameter from full-polarized SIR-C SAR image off the east coast of Korea. The polarization ratio for SIR-C SAR data was estimated to 0.47. To assess the accuracy of the polarization ratio coefficient, pseudo VV-polarized normalized radar cross section (NRCS) values were calculated and compared with the original VV-polarized ones. As a result, the estimated psudo values showed a good agreement with the original VV-polarized data with an root mean square error by 0.99 dB. We applied the psudo NRCS to the estimation of wind speeds based on the CMOD wind models. Comparison of the retrieved wind field with the ECMWF and NCEP/NCAR reanalysis wind data showed relatively small rms errors of 1.88 and 1.91 m/s, respectively. SIR-C HH-polarized SAR wind retrievals met the requirement of the scatterometer winds in overall. However, the polarization ratio coefficient revealed dependence on NRCS value, wind speed, and incident angle.

Verification about Threshold Discharge Computation using GIUH on ungauged small basin (지형학적순간단위도를 이용한 미계측 소유역의 한계유출량 산정 검증)

  • Choi Hyun;Lee Sang-Jin
    • Spatial Information Research
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    • v.14 no.1 s.36
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    • pp.15-27
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    • 2006
  • This paper is about the threshold discharge computation using GIUH(Geomorphoclimatic Instantaneous Unit Hydrograph) on ungauged small basin. GIUH is one of the possible approaches to predicting the hydrograph characteristics. This study is calculated the various ways which are hydrologic characteristics, bankfull flows, unit peak flows(the Clark, the Nakayasu and the S.C.S) as well as threshold runoffs on about $5km^2$ scale at Kyungbuk gampo in subbasin. We are estimated propriety that peak discharge calculated the GIUH from acquiring data by GIS(Geographic Information System) compared to observed peak discharge. And, the threshold discharge was calculated by NRCS(Natural Resources Conservation Service) for a flash flood standard rainfall.

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Optimal Volume Estimation for Non-point Source Control Retention Considering Spatio-Temporal Variation of Land Surface (지표면의 시공간적 변화를 고려한 비점오염원 저감 저류지 최적용량산정)

  • Choi, Daegyu;Kim, Jin Kwan;Lee, Jae Kwan;Kim, Sangdan
    • Journal of Korean Society on Water Environment
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    • v.27 no.1
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    • pp.9-18
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    • 2011
  • In this study the optimal volume for non-point source control retention is estimated considering spatio-temporal variation of land surface. The 3-parameter mixed exponential probability density function is used to represent the statistical properties of rainfall events, and NRCS-CN method is applied as rainfall-runoff transformation. The catchment drainage area is divided into individual $30m{\times}30m$ cells, and runoff curve number is estimated at each cell. Using the derived probability density function theory, the stormwater probability density function at each cell is derived from the rainfall probability density function and NRCS-CN rainfall-runoff transformation. Considering the antecedent soil moisture condition at each cell and the spatial variation of CN value at the whole catchment drainage area, the ensemble stormwater capture curve is established to estimate the optimal volume for an non-point source control retention. The comparison between spatio-temporally varied land surface and constant land surface is presented as a case study for a urban drainage area.

Colour Changes in Meat of Foals as Affected by Slaughtering Age and Post-thawing Time

  • Palo, Pasquale De;Maggiolino, A.;Centoducati, P.;Tateo, A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.12
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    • pp.1775-1779
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    • 2012
  • The aim of the present work was to investigate how colour changes of foal meat can vary after thawing out in relation to the slaughtering age of the horses and to the post-thawing time. Eighteen Italian Heavy Draught Horse (IHDH) foals were used for the trial. They were subdivided in three groups according to their slaughtering age (6, 11 and 18 months). Two different surfaces were investigated for each sample: a fresh cut surface (daily renewed cutting surface: DRCS), and not-renewed cutting surface (NRCS). The redness of both investigated surfaces increased with slaughtering age (p<0.01). Moreover, this parameter decreased during post-thawing time (p<0.01) only on the NRCS, probably due to the myoglobin oxidation processes. Colour is an important visual cue denoting perceived quality by consumers. So, by a chromatic perspective the thawed meat of IHDH foals slaughtered at 6 and 11 months proved to be that which best meets the market requirements.