Editorial

Chow, Ven Te

doi:10.1016/0022-1694(81)90058-5

Cited by 73 publications

(96 citation statements)

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“…In order to separate the overland flow and base flow, a methodology proposed by Chow et al [34] was used in this study. Using this technique, a line that slopes upwards is drawn from the initial hydrograph rise and extends until it intercepts the hydrograph downward.…”

Section: A Base Flow Separation Methodsmentioning

confidence: 99%

Applicability of a Spatially Semi-Distributed Hydrological Model for Watershed Scale Runoff Estimation in Northwest Ethiopia

Zelelew

Melesse

2018

Water

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Estimation of runoff is vital forplanning activities in relation to integrated watershed management and flood protection measures. This research was conducted at one of the catchments in Abbay River (upper Blue Nile River) basin to assess the applicabilityof the Hydrologic Engineering Centre Hydrological Modelling Software (HEC-HMS) modelfor simulation of runoff. It was aimed at selecting the best loss and transform methods in the model, as well as testing the applicability of the calibrated model to ungauged watersheds. Two loss methods such as soil conservation service (SCS) and initial and constant methods with two transform methods including SCS and Clark unit hydrographs were considered in the study for selecting the best combinations applicable in the area. While comparing the simulation results of each combination, better results were obtained in the model set containing the initial and constant loss method and SCS unit hydrograph with a Nash-Sutcliff Efficiency (NSE) of 82.8%, R 2 of 0.83, and 10.71% of relative bias errors, followed by initial and constant with Clarks unit hydrograph, and it can be used for similar ungauged watersheds.

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Section: A Base Flow Separation Methodsmentioning

confidence: 99%

Applicability of a Spatially Semi-Distributed Hydrological Model for Watershed Scale Runoff Estimation in Northwest Ethiopia

Zelelew

Melesse

2018

Water

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“…Antecedent moisture conditions (AMC) II and the corresponding CNII values are considered representative of 50% of the flood events. The value that corresponds to the average humidity conditions (AMC II) is related to the other two typical initial soil moisture conditions (AMC I and AMC III), according to the following empirical relationships [46]: CNI = 4.2 CNII/10 − 0.058 CNII (2) CNIII = 23 CNII/10 + 0.13 CNII…”

Section: Hydrological Modelingmentioning

confidence: 99%

Evaluation of Hydrological and Hydraulic Models Applied in Typical Mediterranean Ungauged Watersheds Using Post-Flash-Flood Measurements

Kastridis

Stathis

2020

Hydrology

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In this paper, three different flash floods episodes were analyzed, which occurred in October 2006, February 2010, and June 2018 in the Chalkidiki peninsula (North Greece). The Soil Conservation Service (SCS) model and a revised assessment of the CN parameter were applied to estimate the flood hydrographs, and Hydrologic Engineering Center's-River Analysis System (HEC-RAS) software was used for the flood simulations. Initially, hydrological and hydraulic models were calibrated at Vatonias watershed (240.90 km 2 , North Greece), where three rain gauges and one water level station are located. Vatonias is located very close to the Stavros ungauged watersheds and presents similar geomorphology and land use conditions. The effectiveness and accuracy of the methodology were validated using post-flash-flood measurements. The root mean square error goodness of fit was used to compare the observed and simulated flood depths. Critical success index was calculated for the assessment of the accuracy of observed and modeled flooded areas. The results showed that the dense forest vegetation was not capable of preventing the flash flood generation or reducing the peak discharge, especially in small watersheds characterized by short concentration times. The main cause of flash flood generation was the human interference that influenced the hydraulic characteristics of streams and floodplains. The revised assessment of the CN parameter enhanced the estimation and spatial distribution of CN over the entire watershed. The results revealed that the proposed methodology could be a very useful tool to researchers and policy makers for flood risk assessment of higher accuracy and effectiveness in ungauged Mediterranean watersheds.Hydrology 2020, 7, 12 2 of 24 settlements with the tolerance of the state have led to the gradual trespass of torrents, the reduction of streambed width, and in some cases to their complete disappearance. Under these circumstances, the hydraulic characteristics of streams and floodplains have been altered dramatically and have resulted in the intensification of the flood phenomena [10][11][12][13]. The protective role of forests from flash flood generation is questionable, and according to previous research studies is very limited, indicating that forests have negligible effects on the reduction of peak discharge during extreme rainfall events [10,12,14,15].Over the past years, considerable efforts have been made to estimate flood risk and simulate flood events, using hydrological and hydraulic models [16][17][18][19][20][21][22][23]. However, these models require the existence of large time series and reliable stream flow and rainfall data, which in most Mediterranean areas are unfortunately not available, especially for medium and small watersheds. To overcome these practical difficulties, post-flash-flood measurements could be considered very useful for the evaluation of the hydrological and hydraulic models by reproducing the flood events and comparing the observed flooded area and flood depth with the si...

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“…The drainage discharge rate of water at the outlet of a paddy plot can be hydraulically calculated using the broad-crested weir equation [24,25,29,36]:…”

Section: Physically-based Approachmentioning

confidence: 99%

Uncertainty in Irrigation Return Flow Estimation: Comparing Conceptual and Physically-Based Parameterization Approaches

Song

Her

Hwang

et al. 2020

Water

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Irrigation return flow (RF) is a critical component of the water cycle in an agricultural watershed, influencing the flow regime of downstream river. As such, it should be accurately quantified when developing water resources management plans and practices. Although many studies have proposed ways to quantify RF, uncertainty in RF estimates has not been determined to improve reliability and credibility. This study examines how conceptual (CON) and physically-based (PHY) parameterization approaches affect RF uncertainty. Results showed that PHY had a smaller amount of RF uncertainty compared to CON, as parameters of the PHY approach could be regulated based on their physical meanings. This study also found that the application of constraints created based on the relationship between the conceptual parameter and physical characteristics of irrigated plots could effectively reduce RF uncertainty made using the CON approach. This study demonstrates the benefits of the physically-based parameterization approach and the application of constraints on conceptual parameters to RF estimation.Water 2020, 12, 1125 2 of 14 rainy days. A modeling approach has been recommended to effectively differentiate runoff by rainfall and RF by irrigation in runoff drained from a plot [3,16,17].RF can be estimated by simulating the overall water balance, which consists of rainfall, irrigation, surface drainage, evapotranspiration, and infiltration. Surface drainage is a key variable for quantifying RF, and two parameterization schemes are commonly used to describe surface water drainage processes: conceptual and physically-based approaches. The conceptual approach (CON) employs parameters that are conceptually defined (rather than physically) using the linear reservoir theory [11,[18][19][20][21]. On the other hand, a physically-based parameterization approach (PHY) represents the drainage processes using the broad-crested weir equation [3,7,[22][23][24][25].Parameterization schemes have their own strengths and weaknesses in terms of complexity, accuracy, and uncertainty. Even when there are no drainage observations for calibration, for instance, the parameter values of PHY may be accurately estimated from their physical meanings. In contrast, it can be difficult to reasonably determine the values of conceptual parameters without calibration due to the scale-dependency of system heterogeneity and nonlinearity [26]. In the case of an ungauged watershed, the applicability of conceptual parameters has not received sufficient systematic analysis to guide the selection of approaches.This study evaluated the applicability of conceptual and physically-based parameterization approaches for estimating RF of ungauged watersheds. The accuracy and uncertainty of RF estimates made using the two approaches were compared to each other. We also discuss how expert knowledge can help refine the value range of a conceptual parameter, aiding the reduction of uncertainty in the conceptual approach [27,28]. This study demonstrates how hydrological reasoning ca...

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Editorial

Cited by 73 publications

References 0 publications

Applicability of a Spatially Semi-Distributed Hydrological Model for Watershed Scale Runoff Estimation in Northwest Ethiopia

Applicability of a Spatially Semi-Distributed Hydrological Model for Watershed Scale Runoff Estimation in Northwest Ethiopia

Evaluation of Hydrological and Hydraulic Models Applied in Typical Mediterranean Ungauged Watersheds Using Post-Flash-Flood Measurements

Uncertainty in Irrigation Return Flow Estimation: Comparing Conceptual and Physically-Based Parameterization Approaches

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