scholarly journals Research on the initial abstraction – storage ratio and its effect on hydrograph simulation at a watershed in Greece

2007 ◽  
Vol 4 (4) ◽  
pp. 2169-2204 ◽  
Author(s):  
E. A. Baltas ◽  
N. A. Dervos ◽  
M. A. Mimikou
Keyword(s):  
Empirical Equation ◽  
Storm Events ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Initial Abstraction ◽  
Time Period ◽  
The Difference ◽  
Runoff Events

Abstract. The present research was conducted at an experimental watershed in the prefecture of Attica, Greece, using the selected observed rainfall-runoff events from a four-year time period. The objectives of this study were two: The first was the determination of the initial abstraction Ia – watershed storage S ratio. The average ratio (Ia/S) was equal to 0.014. The corresponding ratio at a subwatershed was 0.037. The difference was attributed to the different spatial distribution of landuses at the extent of the watershed. The second objective of the study was to examine the effect of the SCS empirical equation on hydrograph simulation. This was investigated through the comparison between the observed and two different simulated hydrographs at each one out of eighteen selected storm events. The simulated hydrographs were calculated by applying on the watershed's unit hydrograph two time distributions of excess rainfall that derived from the SCS method using two different approaches. In the first approach, the initial abstraction was determined from the observed rainfall-runoff data, while in the second, it was calculated using the SCS empirical equation. It was found that the SCS empirical equation estimates greater amount of initial abstraction and leads to the delayed start of the excess rainfall and the simulated runoff. This resulted in the overestimation of the peak flow rate and the time to peak at the majority of the storm events.

scholarly journals Technical Note: Determination of the SCS initial abstraction ratio in an experimental watershed in Greece

2007 ◽  
Vol 11 (6) ◽  
pp. 1825-1829 ◽  
Author(s):  
E. A. Baltas ◽  
N. A. Dervos ◽  
M. A. Mimikou
Keyword(s):  
Spatial Distribution ◽  
Technical Note ◽  
Rainfall Runoff ◽  
Average Ratio ◽  
Initial Abstraction ◽  
The Difference ◽  
Geological Formations ◽  
Scs Cn ◽  
Runoff Events

Abstract. The present study was conducted in an experimental watershed in Attica, Greece, using observed rainfall/runoff events. The objective of the study was the determination of the initial abstraction ratio of the watershed. The average ratio (Ia/S) of the entire watershed was equal to 0.014. The corresponding ratio at a subwatershed was 0.037. The difference was attributed to the different spatial distribution of landuses and geological formations at the extent of the watershed. Both of the determined ratios are close to the ratio value of 0.05 that has been suggested from many studies for the improvement of the SCS-CN method.

scholarly journals Initial abstraction ratio and Curve Number estimation using rainfall and runoff data from a tropical watershed

RBRH ◽  
2019 ◽  
Vol 24 ◽  
Author(s):  
Luiz Claudio Galvão do Valle Junior ◽  
Dulce Buchala Bicca Rodrigues ◽  
Paulo Tarso Sanches de Oliveira
Keyword(s):  
Conversion Factor ◽  
Poor Performance ◽  
Curve Number ◽  
Storm Events ◽  
Rainfall Runoff ◽  
Initial Abstraction ◽  
Rainfall Depth ◽  
Standard Value ◽  
Tropical Watershed ◽  
Runoff Events

ABSTRACT The Curve Number (CN) method is extensively used for predict surface runoff from storm events. However, remain some uncertainties in the method, such as in the use of an initial abstraction (λ) standard value of 0.2 and on the choice of the most suitable CN values. Here, we compute λ and CN values using rainfall and runoff data to a rural basin located in Midwestern Brazil. We used 30 observed rainfall-runoff events with rainfall depth greater than 25 mm to derive associated CN values using five statistical methods. We noted λ values ranging from 0.005 to 0.455, with a median of 0.045, suggesting the use of λ = 0.05 instead of 0.2. We found a S0.2 to S0.05 conversion factor of 2.865. We also found negative values of Nash-Sutcliffe Efficiency (to the estimated and observed runoff). Therefore, our findings indicated that the CN method was not suitable to estimate runoff in the studied basin. This poor performance suggests that the runoff mechanisms in the studied area are dominated by subsurface stormflow.

scholarly journals A Polynomial Method Approximating S-Curve with Limited Availability of Reliable Rainfall Data

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3447
Author(s):  
Kee-Won Seong ◽  
Jang Hyun Sung
Keyword(s):  
Step Response ◽  
Polynomial Method ◽  
Storm Events ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
General Applicability ◽  
Runoff Modeling ◽  
Instantaneous Unit Hydrograph ◽  
S Curve

A methodology named the step response separation (SRS) method for deriving S-curves solely from the data for basin runoff and the associated instantaneous unit hydrograph (IUH) is presented. The SRS method extends the root selection (RS) method to generate a clearly separated S-curve from runoff incorporated in mathematical procedure utilizing the step response function. Significant improvements in performance are observed in separating the S-curve with rainfall. A procedure to evaluate the hydrologic stability provides ways to minimize the oscillation of the S-curve associated with the determination of infiltration and baseflow. The applicability of the SRS method to runoff reproduction is examined by comparison with observed basin runoff based on the RS method. The SRS method applied to storm events for the Nenagh basin resulted in acceptable S-curves and showed its general applicability to optimization for rainfall-runoff modeling.

scholarly journals Derivation of S-Curve from Oscillatory Hydrograph Using Digital Filter

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1456
Author(s):  
Kee-Won Seong ◽  
Jang Hyun Sung
Keyword(s):  
Digital Filter ◽  
Model Performance ◽  
Performance Criteria ◽  
Rainfall Runoff ◽  
Small Watershed ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
S Curve ◽  
And Performance ◽  
Smooth Data

An oscillatory S-curve causes unexpected fluctuations in a unit hydrograph (UH) of desired duration or an instantaneous UH (IUH) that may affect the constraints for hydrologic stability. On the other hand, the Savitzky–Golay smoothing and differentiation filter (SG filter) is a digital filter known to smooth data without distorting the signal tendency. The present study proposes a method based on the SG filter to cope with oscillatory S-curves. Compared to previous conventional methods, the application of the SG filter to an S-curve was shown to drastically reduce the oscillation problems on the UH and IUH. In this method, the SG filter parameters are selected to give the minimum influence on smoothing and differentiation. Based on runoff reproduction results and performance criteria, it appears that the SG filter performed both smoothing and differentiation without the remarkable variation of hydrograph properties such as peak or time-to peak. The IUH, UH, and S-curve were estimated using storm data from two watersheds. The reproduced runoffs showed high levels of model performance criteria. In addition, the analyses of two other watersheds revealed that small watershed areas may experience scale problems. The proposed method is believed to be valuable when error-prone data are involved in analyzing the linear rainfall–runoff relationship.

scholarly journals Determination of Curve Number for snowmelt-runoff floods in a small catchment

2015 ◽  
Vol 370 ◽  
pp. 167-170 ◽  
Author(s):  
L. Hejduk ◽  
A. Hejduk ◽  
K. Banasik
Keyword(s):  
Soil Conservation ◽  
Curve Number ◽  
Rainfall Runoff ◽  
Snowmelt Runoff ◽  
Ungauged Catchments ◽  
Department Of Agriculture ◽  
Small Catchment ◽  
Rainfall Depth ◽  
Runoff Events

Abstract. One of the widely used methods for predicting flood runoff depth from ungauged catchments is the curve number (CN) method, developed by Soil Conservation Service (SCS) of US Department of Agriculture. The CN parameter can be computed directly from recorded rainfall depths and direct runoff volumes in case of existing data. In presented investigations, the CN parameter has been computed for snowmelt-runoff events based on snowmelt and rainfall measurements. All required data has been gathered for a small agricultural catchment (A = 23.4 km2) of Zagożdżonka river, located in Central Poland. The CN number received from 28 snowmelt-runoff events has been compared with CN computed from rainfall-runoff events for the same catchment. The CN parameter, estimated empirically varies from 64.0 to 94.8. The relation between CN and snowmelt depth was investigated in a similar procedure to relation between CN and rainfall depth.

scholarly journals Comparative evaluation of the balance and synoptic methods of determination of the assimilation volume of water ecosystems

2018 ◽  
Vol 3 (1) ◽  
pp. 3-8
Author(s):  
H. H. Asadov ◽  
S. A. Askerova
Keyword(s):  
Winter Season ◽  
Time Interval ◽  
The Caspian Sea ◽  
Quantitative Correlation ◽  
Time Period ◽  
The Difference ◽  
Water Ecosystems ◽  
Mass Volume ◽  
Assimilation Capacity

The assimilation capacity of sea waters is known to be defined as a maximum dynamic volume of such content of pollutants which can be accumulated, destructed, transformed and excluded out of the limits of the ecosystem during a curtain time period if normal condition functioning of the ecosystem is not disturbed. The paper focuses on comparative analysis of assimilation capacity calculated using balance and synoptic methods. Geometrical representation of the compared methods in 3-D space {Т, V, C} is suggested, where T is time interval, V is water mass volume, C is concentration of pollutants. Quantitative correlation between two considered values of assimilation capacity is given. The results obtained are applied for some areas of coastal northern zones of Azerbaijan sector of the Caspian Sea. It is shown that in winter season the value of assimilation capacity calculated using synoptic method is somewhat lower in comparison with the same parameter calculated by balance method and equal to 0.6–0.8 share of the latter. Such a result can be considered as much better in comparison with the known results where the difference reaches one order.

scholarly journals ANALISIS KETERSEDIAAN AIR PADA DAS INDRAGIRI HILIR MENGGUNAKAN MODEL IHACRES

2021 ◽  
Vol 7 (3) ◽  
pp. 153-159
Author(s):  
Jusatria Jusatria ◽  
Syahnandito Syahnandito ◽  
M Gasali M ◽  
Rezky Kinanda
Keyword(s):  
Water Availability ◽  
Time Distribution ◽  
Conceptual Analysis ◽  
Water Discharge ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
Runoff Modeling ◽  
Nonlinear Loss ◽  
Rain Data

The imbalance that occurs between the availability of water and the water needs needed in Indragiri Hilir requires a conseptual review and evaluation. The all-time distribution of water availability is greatly influenced by the distribution of rain throughout the year. Conceptual analysis of water discharge with the help of IHACRES software can help analyze DAS indragiri Hilir discharge. Rainfall-runoff modeling is used to predict the value against the runoff, using the IHACRES model. The IHACRES model produces nonlinear loss module parameters and linear unit hydrograph modules. AWLR will be used, namely Bt. Kuantan Rengat station, Rain Data which will be used from Tembilahan station and climatology used from Air Molek  station. Determination of success in the model used the equations R2 and R to calculate the deviation that occurs. The calibration, verification and simulation phases begin in 2010-2015. The results of conceptual analysis of water discharge in Indragiri Hilir watershed, mainstay discharge results for irrigation purposes with a probability of 80% maximum discharge occurred in February by 4.33 m3 / s and minimum discharge occurred in April by 0.34 m3/s. Overall availability of water on site is available throughout the year. but it cannot be used for hydropower needs because the available discharge may be affected by tidal factors.   Ketidakseimbangan yang terjadi antara ketersediaan air dan kebutuhan air yang diperlukan di Indragiri Hilir memerlukan peninjauan dan evaluasi yang konseptual. Distribusi ketersedian air sepanjang waktu sangat dipengaruhi oleh distribusi hujan  sepanjang tahun . Analisis konseptual debit air dengan bantuan software IHACRES dapat membantu menganalisis debit DAS indragiri hilir. Pemodelan rainfall-runoff digunakan untuk   memprediksi nilai terhadap runoff salah satunya yaitu menggunakan model IHACRES. Model IHACRES menghasilkan parameter nonlinier loss module dan linier unit hydrograph module. AWLR akan digunakan yaitu stasiun Bt. Kuantan Rengat, Data Hujan yang akan digunakan  yaitu dari stasiun Tembilahan dan klimatologi yang digunakan dari stasiun Air Molek. Penentuan  keberhasilan pada model digunakan persamaan R2 dan R untuk menghitung simpangan yang terjadi. Tahap  kalibrasi, verifikasi dan simulasi dimulai tahun 2010-2015. Hasil analisis konseptual debit air pada DAS Indragiri Hilir, hasil debit andalan untuk keperluan irigasi dengan probabilitas 80% debit maksimum terjadi pada bulan Februari sebesar 4,33 m3/s dan debit minimum terjadi pada bulan April sebesar 0,34 m3/s. Secara keseluruhan ketersediaan air di lokasi tersedia sepanjang tahun. tetapi tidak bisa digunakan untuk kebutuhan PLTA karena debit yang tersedia mungkin dipengaruhi faktor pasang surut    

scholarly journals Comparative Analysis Between Pre-Trading Volume Activities with Post Event Tax Amnesty

2020 ◽  
Vol 3 (3) ◽  
pp. 39-49
Author(s):  
Bayu Teguh Imani ◽  
Satia Nur Maharani ◽  
Sheila Febriani Putri
Keyword(s):  
Trading Volume ◽  
Abnormal Returns ◽  
Volume Activity ◽  
Tax Amnesty ◽  
Time Period ◽  
Before And After ◽  
The Difference ◽  
Events Study ◽  
Observation Period

This study aims to determine the difference of Trading Volume Activity that exceed before and after the determination of tax amnesty policy and to figure out the existence of abnormal return formed before and after the determination of the tax amnesty. This study uses the Events Study method with 100 days observation for the estimation period and 15 days for event period. The study used a group of perception banks that listed in BEI in 2016 period as population and 22 selected stocks to be sampled by using saturated sampling method. During the observation period, positive and negative abnormal returns with fluctuating movements were formed. Trading Volume Activity changes between before and after-tax amnesty policy. From these two results, it can be concluded that there was leakage of information before the event published that indicates the form of market efficiency of Indonesia is half strong (semistrong form). Further research is suggested to use the calculation method and time period different from this research in order to obtain more accurate results.

Rainfall Runoff Hydrograph Prediction Using Dynamic Wave Based Instantaneous Unit Hydrograph

2020 ◽  
Author(s):  
Minyeob Jeong ◽  
Jongho Kim ◽  
Dae-Hong Kim
Keyword(s):  
Rainfall Intensity ◽  
Wave Model ◽  
Test Results ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
Time To Peak ◽  
Instantaneous Unit Hydrograph ◽  
Runoff Hydrographs ◽  
Dynamic Wave ◽  
Peak Value

<p>A method to predict runoff based on the instantaneous unit hydrograph and dynamic wave approximation is proposed. The method is capable of generating IUH of a watershed without the need of observed rainfall and runoff data, and only topography and surface roughness of a watershed are needed. IUHs were generated using a dynamic wave model and S-hydrograph method, and IUH generated was a function of both watershed and rainfall properties. The ordinate of IUH depends on the rainfall intensities, and the peak value of IUH was proportional to the rainfall intensity while the time to peak of the IUH was inversely proportional to the rainfall intensity.  Corresponding IUHs for different rainfall intensities were used to generate runoff hydrographs. Since the IUH is generated using a dynamic wave model, it can be a tool to physically simulate the rainfall-runoff processes. Also, nonlinear rainfall-runoff relationship can be taken into account by expressing IUH as a function of rainfall excess intensity. Several test results in ideal basins and in a real watershed show that the proposed method has a good capability in predicting runoff, while several limitations remain.</p><p>Keywords: rainfall-runoff, instantaneous unit hydrograph, dynamic wave model</p>

A comparison of three techniques to determine the herbage intake of dairy cows grazing kikuyu (Pennisetum clandestinum) pasture

1996 ◽  
Vol 36 (1) ◽  
pp. 23 ◽  
Author(s):  
M Reeves ◽  
WJ Fulkerson ◽  
RC Kellaway ◽  
H Dove
Keyword(s):  
Quality Parameters ◽  
Pennisetum Clandestinum ◽  
Concentrate Supplementation ◽  
Herbage Intake ◽  
Time Period ◽  
The Difference ◽  
Standard Energy

Two studies were conducted to compare the precision of estimating kikuyu grass (Pennisetum clandestinum) intake by Friesian cows fed 0, 3 or 6 kg of cereal-based concentrate/cow.day, using a rising plate meter (RPM), standard energy requirements in reverse (RS) and plant wax alkanes as internal markers. Study 1 compared herbage intake estimates obtained using the RPM and RS techniques over a 45-day period. RS estimates were based on the metabolisable energy (ME) of ration components derived from in vitro organic matter digestibility (OMD) values. Pregrazing calibration equations for the RPM determined at 2-weekly intervals differed significantly (P<0.01) from postgrazing calibrations; consequently separate equations were used to determine pasture intake as the difference in pre- and post-grazing pasture mass. Estimates of total intake were lower using the RPM than the RS technique for the groups fed 0 kg (12.5 v. 14.8 kg dry matter (DM)/cow.day) and 3 kg (10.4 v. 12.9 kg DM/cow.day) of concentrate, and higher for those receiving 6 kg (10.5 v. 7.8 kg DM/cow.day). In study 2 (12 days duration), intakes derived using alkanes were compared with intakes estimated using the RS and RPM techniques. The C32/C33 alkane pair gave the closest estimate of herbage intake to that obtained using the RPM and RS techniques. Whole diet in vivo DM digestibility (DMD), determined by the alkane method, was not significantly different between the 3 groups (mean 70%), suggesting that digestibility of the kikuyu declined with increasing concentrate supplementation. The in vivo DMD of kikuyu alone (determined in the non-concentrate-supplemented cows) was considerably higher (69.5%) than the OMD determined in vitro (63.9%). By using in vivo rather than in vitro digestibilities for kikuyu in the RS calculations, the intake estimates were reduced by 17%, and for the 0 kg concentrate group, intake estimates aligned closely to predictions of the RPM and alkanes. Concentrates in the diet resulted in lower intake estimates using the RS technique compared with the RPM and alkane techniques. This was most evident at the 6 kg level of supplementation where RS predicted kikuyu intake to be 6.5 kg DM/cow.day using in vivo-derived DMD and this was substantially lower than either the RPM (12.4 kg DM/cow.day) or alkanes (9.2 kg DM/cow.day). The alkane technique provided a direct and precise method of measuring the intake of individual cows grazing tightly-managed kikuyu pasture. With the use of accurate animal production and feed quality parameters, the RS technique can provide sensible pasture intake estimates over an extended time period. The RPM technique is useful for obtaining herd estimates of pasture intake and for the determination of pasture parameters associated with intake.

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