<abstract xmlns="http://www.w3.org/1999/xhtml"><p>One of the most often-used parameters that describes morphology and runoff from a watershed is the time of concentration (Tc). At gauged watersheds, Tc can be determined using rainfall and a runoff hydrograph, while for ungauged watersheds, empirical equations are used. A good initial estimate of Tc greatly improves the accuracy of runoff predictions. In our study, we applied 14 empirical equations to determine Tc. Tarján Creek, which is located in northeastern Hungary, was selected as the trial gauged watershed. It is located in a mountainous region with an area of 72 km<sup>2</sup>. The input parameters for the empirical equations were determined using geoinformatical tools. To evaluate the accuracy of the empirical equations, HEC-HMS was used to model the runoff. Using the measured runoff data, both continuous and event-based models were calibrated. For direct runoff, Clark’s unit hydrograph was selected. Tc is one of the input parameters for this model. After the calibration, the estimates from the empirical equations for Tc were compared to the HEC-HMS calibrated values for each subwatershed. The empirical estimates varied greatly. The Wisnovszky-equation, which is most often used in Hungary, underestimated Tc.</p></abstract>

One of the most often-used parameters that describes morphology and runoff from a watershed is the time of concentration (Tc). At gauged watersheds, Tc can be determined using rainfall and a runoff hydrograph, while for ungauged watersheds, empirical equations are used. A good initial estimate of Tc greatly improves the accuracy of runoff predictions. In our study, we applied 14 empirical equations to determine Tc. Tarján Creek, which is located in northeastern Hungary, was selected as the trial gauged watershed. It is located in a mountainous region with an area of 72 km2. The input parameters for the empirical equations were determined using geoinformatical tools. To evaluate the accuracy of the empirical equations, HEC-HMS was used to model the runoff. Using the measured runoff data, both continuous and event-based models were calibrated. For direct runoff, Clark’s unit hydrograph was selected. Tc is one of the input parameters for this model. After the calibration, the estimates from the empirical equations for Tc were compared to the HEC-HMS calibrated values for each subwatershed. The empirical estimates varied greatly. The Wisnovszky-equation, which is most often used in Hungary, underestimated Tc.

Comparing Methods for Computing the Time of Concentration in a Medium-Sized Hungarian Catchment

Msc Student, Budapest University of Technology and Economics

Assistant Professor, Budapest University of Technology and Economics

Associate Professor, Széchenyi István University

Slovak Journal of Civil Engineering

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

One of the most often-used parameters that describes morphology and runoff from a watershed is the time of concentration (Tc). At gauged watersheds, Tc can be...

Comparing Methods for Computing the Time of Concentration in a Medium-Sized Hungarian Catchment

Published Online: Dec 30, 2016

Page range: 8 - 14

DOI: https://doi.org/10.1515/sjce-2016-0017

Keywords
Time of concentration, Rainfall-runoff modelling, HEC – HMS, Event-based model

© 2016 Faculty of Civil Engineering, Slovak University of Technology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Comparing Methods for Computing the Time of Concentration in a Medium-Sized Hungarian Catchment

Published Online: Dec 30, 2016

Page range: 8 - 14

DOI: https://doi.org/10.1515/sjce-2016-0017

KeywordsTime of concentration, Rainfall-runoff modelling, HEC – HMS, Event-based model

© 2016 Faculty of Civil Engineering, Slovak University of Technology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Time of concentration, Rainfall-runoff modelling, HEC – HMS, Event-based model