scholarly journals Applying a Graphical Method in Evaluation of Empirical Methods for Estimating Time of Concentration in an Arid Region

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2624
Author(s):  
Ali Zahraei ◽  
Ramin Baghbani ◽  
Anna Linhoss
Keyword(s):  
Arid Region ◽  
Graphical Method ◽  
Empirical Method ◽  
Structure Design ◽  
Rainfall Runoff ◽  
Empirical Methods ◽  
Time Of Concentration ◽  
Improve Accuracy ◽  
Runoff Events ◽  
Ungauged Watersheds

At gauged watersheds, the time of concentration can be estimated using rainfall-runoff data; however, at ungauged watersheds, empirical methods are used instead. Large errors in the application of empirical methods may cause inaccurate modeling of floods and unreliable structure design. In this paper, methods for calculating the time of concentration (Tc) were compared to identify the best equation for estimating Tc in ungauged watersheds of an arid region. The graphical method, based on measured data, was compared to 15 empirical methods to determine which empirical method returned the best results. The graphical method was applied to 33 rainfall-runoff events in four rural sub-watersheds located in the central parts of Hormozgan province, Iran. A ranking-based procedure was used to select the best performing empirical methods. To minimize bias and improve accuracy, the best performing empirical methods were modified by adjusting their formulas. According to the study, three empirical methods: (1) Williams, (2) Pilgrim and Mac Dermott, and (3) Arizona DOT, performed the best in the study areas. The results also showed that the modified Williams and Arizona DOT’s formulas were able to estimate the time of concentration in ungauged watersheds with an error lower than 1%.

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 Rainfall-induced release of microbes from manure: model development, parameter estimation, and uncertainty evaluation on small plots

2016 ◽  
Vol 14 (3) ◽  
pp. 443-459 ◽  
Author(s):  
Keewook Kim ◽  
Gene Whelan ◽  
Marirosa Molina ◽  
S. Thomas Purucker ◽  
Yakov Pachepsky ◽  
...  
Keyword(s):  
Model Development ◽  
Fecal Coliforms ◽  
Time Varying ◽  
Rainfall Runoff ◽  
Swine Slurry ◽  
Four Seasons ◽  
Release Curve ◽  
Parameter Values ◽  
Runoff Events ◽  
Parameter Distributions

A series of simulated rainfall-runoff experiments with applications of different manure types (cattle solid pats, poultry dry litter, swine slurry) was conducted across four seasons on a field containing 36 plots (0.75 × 2 m each), resulting in 144 rainfall-runoff events. Simulating time-varying release of Escherichia coli, enterococci, and fecal coliforms from manures applied at typical agronomic rates evaluated the efficacy of the Bradford–Schijven model modified by adding terms for release efficiency and transportation loss. Two complementary, parallel approaches were used to calibrate the model and estimate microbial release parameters. The first was a four-step sequential procedure using the inverse model PEST, which provides appropriate initial parameter values. The second utilized a PEST/bootstrap procedure to estimate average parameters across plots, manure age, and microbe, and to provide parameter distributions. The experiment determined that manure age, microbe, and season had no clear relationship to the release curve. Cattle solid pats released microbes at a different, slower rate than did poultry dry litter or swine slurry, which had very similar release patterns. These findings were consistent with other published results for both bench- and field-scale, suggesting the modified Bradford–Schijven model can be applied to microbial release from manure.

scholarly journals Examination of aerial diatom flushing across watersheds in Luxembourg, Oregon and Slovakia for tracing episodic hydrological connectivity

2015 ◽  
Vol 63 (3) ◽  
pp. 235-245 ◽  
Author(s):  
Laurent Pfister ◽  
Carlos E. Wetzel ◽  
Núria Martínez-Carreras ◽  
Jean François Iffly ◽  
Julian Klaus ◽  
...  
Keyword(s):  
Water Source ◽  
Interdisciplinary Studies ◽  
Transport Processes ◽  
Hydrological Connectivity ◽  
Freshwater Species ◽  
Rainfall Runoff ◽  
Holistic View ◽  
Preliminary Examination ◽  
Open Questions ◽  
Runoff Events

Abstract Hydrological processes research remains a field that is severely measurement limited. While conventional tracers (geochemicals, isotopes) have brought extremely valuable insights into water source and flowpaths, they nonetheless have limitations that clearly constrain their range of application. Integrating hydrology and ecology in catchment science has been repeatedly advocated as offering potential for interdisciplinary studies that are eventually to provide a holistic view of catchment functioning. In this context, aerial diatoms have been shown to have the potential for detecting of the onset/cessation of rapid water flowpaths within the hillslope-riparian zone-stream continuum. However, many open questions prevail as to aerial diatom reservoir size, depletion and recovery, as well as to their mobilisation and transport processes. Moreover, aerial diatoms remain poorly known compared to freshwater species and new species are still being discovered. Here, we ask whether aerial diatom flushing can be observed in three catchments with contrasting physiographic characteristics in Luxembourg, Oregon (USA) and Slovakia. This is a prerequisite for qualifying aerial diatoms as a robust indicator of the onset/cessation of rapid water flowpaths across a wider range of physiographical contexts. One species in particular, (Hantzschia amphioxys (Ehr.) Grunow), was found to be common to the three investigated catchments. Aerial diatom species were flushed, in different relative proportions, to the river network during rainfall-runoff events in all three catchments. Our take-away message from this preliminary examination is that aerial diatoms appear to have a potential for tracing episodic hydrological connectivity through a wider range of physiographic contexts and therefore serve as a complementary tool to conventional hydrological tracers.

Bayesian Estimation of Soil-Water Characteristic Curves

2021 ◽  
Author(s):  
Jie Zhang ◽  
Shuai Yang ◽  
Lulu Zhang ◽  
Mingliang Zhou
Keyword(s):  
Soil Water ◽  
Bayesian Model ◽  
Characteristic Curve ◽  
Measurement Data ◽  
Bayes Theorem ◽  
Empirical Method ◽  
Measured Data ◽  
Suggested Method ◽  
Empirical Methods ◽  
Soil Water Characteristic Curves

The soil-water characteristic curve (SWCC) is a significant prerequisite for studying the mechanical properties of unsaturated soil. As experimental measurement of the SWCC is time-consuming, empirical methods have been suggested to estimate the SWCC. However, the uncertainty associated with SWCC can be substantial. In this paper, a hybrid method based on Bayes’ theorem is suggested to estimate the SWCC, where an empirical method can be used to provide prior knowledge about the SWCC, and a limited quantity of measured data is used to update the SWCC. The Bayesian model is then solved with a Markov Chain Monte Carlo simulation. Through the suggested method, the valuable information provided by the empirical method can be combined with the measurement data. The suggested method can not only provide the best estimate about the SWCC, but also account for the associated uncertainty. Also, the effect of more measured points on the estimation of SWCC can be quantified. The suggested method provides a practical means to estimate the SWCC using a limited amount of data.

Probablistic analysis of runoff simulations in a small urban catchment

1997 ◽  
Vol 36 (8-9) ◽  
pp. 51-56
Author(s):  
F. Calomino ◽  
P. Veltri ◽  
P. Piro ◽  
J. Niemczynowicz
Keyword(s):  
Frequency Distribution ◽  
Basic Question ◽  
Rainfall Runoff ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Frequency Distributions ◽  
The Common ◽  
Runoff Events ◽  
Peak Discharges ◽  
Good Agreement

In Urban Hydrology, a basic question is whether or not the common methods involving the use of design storms bring to the the some results obtained by those methods that make use of real storms. In general, one can say that different design storms give good results when used with the appropriate model, or, conversely, that good results can be achieved through careful model calibration. On the basis of 51 rainfall-runoff recordings obtained from the experimental catchment of Luzzi (Cosenza, Italy), the frequency distribution of the observed peak discharges was initially computed. Then the runoff events were simulated using Wallrus, a well known simulation model, taking as input the observed precipitations. The frequency distribution of the simulated peak discharges was compared to that of the observed ones, with the aim of calibrating the model on a statistical basis. After that, the rainfall events were analysed, obtaining the frequency distributions of the observed intensities over several durations and developing IDF curves of given frequencies and, then, the Chicago design storms. The plotting positions of the peak discharges simulated by this way show a good agreement with the distribution of both the observed peak discharges and the peak discharges simulated through the real storms.

scholarly journals Picturing and modeling catchments by representative hillslopes

2017 ◽  
Vol 21 (2) ◽  
pp. 1225-1249 ◽  
Author(s):  
Ralf Loritz ◽  
Sibylle K. Hassler ◽  
Conrad Jackisch ◽  
Niklas Allroggen ◽  
Loes van Schaik ◽  
...  
Keyword(s):  
Expert Knowledge ◽  
Water Dynamics ◽  
Rainfall Runoff ◽  
Data Set ◽  
Physically Based Model ◽  
Optimal Representation ◽  
Physically Based ◽  
Physically Based Models ◽  
Streamflow Data ◽  
Runoff Events

Abstract. This study explores the suitability of a single hillslope as a parsimonious representation of a catchment in a physically based model. We test this hypothesis by picturing two distinctly different catchments in perceptual models and translating these pictures into parametric setups of 2-D physically based hillslope models. The model parametrizations are based on a comprehensive field data set, expert knowledge and process-based reasoning. Evaluation against streamflow data highlights that both models predicted the annual pattern of streamflow generation as well as the hydrographs acceptably. However, a look beyond performance measures revealed deficiencies in streamflow simulations during the summer season and during individual rainfall–runoff events as well as a mismatch between observed and simulated soil water dynamics. Some of these shortcomings can be related to our perception of the systems and to the chosen hydrological model, while others point to limitations of the representative hillslope concept itself. Nevertheless, our results confirm that representative hillslope models are a suitable tool to assess the importance of different data sources as well as to challenge our perception of the dominant hydrological processes we want to represent therein. Consequently, these models are a promising step forward in the search for the optimal representation of catchments in physically based models.

Understanding spatio‐temporal rainfall‐runoff changes in a semi‐arid region.

2020 ◽  
Author(s):  
Santosh K Aryal ◽  
Richard P Silberstein ◽  
Guobin Fu ◽  
Geoff Hodgson ◽  
Stephen P Charles ◽  
...  
Keyword(s):  
Arid Region ◽  
Rainfall Runoff ◽  
Runoff Changes ◽  
Spatio Temporal ◽  
Semi Arid Region ◽  
Semi Arid

scholarly journals Effects of Roughness Coefficients and Complex Hillslope Morphology on Runoff Variables under Laboratory Conditions

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2550 ◽  
Author(s):  
Masoud Meshkat ◽  
Nosratollah Amanian ◽  
Ali Talebi ◽  
Mahboobeh Kiani-Harchegani ◽  
Jesús Rodrigo-Comino
Keyword(s):  
Soil Erosion ◽  
Peak Discharge ◽  
Control Measures ◽  
P Value ◽  
Rainfall Runoff ◽  
Runoff Generation ◽  
Mean Values ◽  
Time Of Concentration ◽  
Significant Difference ◽  
The Impact

The geometry of hillslopes (plan and profile) affects soil erosion under rainfall-runoff processes. This issue comprises of several factors, which must be identified and assessed if efficient control measures are to be designed. The main aim of the current research was to investigate the impact of surface Roughness Coefficients (RCs) and Complex Hillslopes (CHs) on runoff variables viz. time of generation, time of concentration, and peak discharge value. A total of 81 experiments were conducted with a rainfall intensity of 7 L min−1 on three types of soils with different RCs (i.e., low = 0.015, medium = 0.016, and high = 0.018) and CHs (i.e., profile curvature and plan shape). An inclination of 20% was used for three replications. The results indicate a significant difference (p-value ≤ 0.001) in the above-mentioned runoff variables under different RCs and CHs. Our investigation of the combined effects of RCs and CHs on the runoff variables shows that the plan and profile impacts are consistent with a variation in RC. This can implicate that at low RC, the effect of the plan shape (i.e., convergent) on runoff variables increases but at high RC, the impact of the profile curvature overcomes the plan shapes and the profile curvature’s changes become the criteria for changing the behavior of the runoff variables. The lowest mean values of runoff generation and time of concentration were obtained in the convex-convergent and the convex-divergent at 1.15 min and 2.68 min, respectively, for the soil with an RC of 0.015. The highest mean of peak discharge was obtained in the concave-divergent CH in the soil with an RC of 0.018. We conclude that these results can be useful in order to design planned soil erosion control measures where the soil roughness and slope morphology play a key role in activating runoff generation.

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