Selection of the best empirical formula to estimate time of concentration in urban watersheds (Case study: Mahdasht town)

Shahbazi, Ali; Khaliqi Sygarodi, Shahram; Malekian, Arash; Salajegheh, Ali

doi:10.22059/jrwm.2014.52835

Document Type : Research Paper

Authors

¹ PhD. Candidate, Faculty of Natural Resources, University of Tehran, Karaj, Iran

² Assistant Professor, Faculty of Natural Resources, University of Tehran, Karaj, Iran

³ Professor, Faculty of Natural Resources, University of Tehran, Karaj, Iran In

https://doi.org/10.22059/jrwm.2014.52835

Abstract

In order to decrease the risks associated with the management of urban watersheds, the use of proper methods is an essential task to estimate the runoff with a high degree of confidence. Time of concentration is one of factors that impacts on peak discharge and runoff volume. The objective of this study is to select the best method among the empirical formulas for estimating the time of concentration. In this study, for determination of actual time of concentration, the field method based on measuring the travel time by using floating-object method was employed. To select the best empirical formula of the time of concentration, the statistical criteria including percentage Relative Error (RE), Root Mean square error (RMSE), Average percentage Relative Error (RME), Nash - Sutcliffe criteria (NS) and determination coefficient were used. Then, differences among the estimations obtained from empirical equations were compared with the actual values. The results of this study based on comparison of the relative error in each interval showed that in the reach No. 2, empirical formulas of California, Chow, Carter and Federal Aviation, with percentage error of 2.7, 2.9, 4.4 and 4.4 have showed the best estimation, respectively. The equation proposed by Kirby with percentage error of 1 in the reach No. 3, the equation of Ventura with percentage error 8.5 in the reach No. 9 and the equation of rational hydrograph with percentage error 4.8 in the reach No. 10 have showed the best estimates. Therefore, it is recommended to use the empirical formula that has the lowest percentage of error for areas with features similar to the studied reaches. In general, the results show that only rational hydrograph method in all of the reaches has the lowest error and then provides the most proper estimates compared than others.

Keywords

References

[1] Abustan, I., Sulaiman, A.H., Abdul Wahid, N. and Baharudin, F. )2008(. Determination of Rainfall-Runoff Characteristics in An Urban, (Case study: Sungai Kerayong Catchment, Kuala Lumpur). 11th International Conference on Urban Drainage.

[2] Alizadeh, A. )2006(. Principles of applied hydrology. 20ed Edition, University of Mashhad Press, 807p.

[3] Arabi, M. and Govindaraju, R.S. and Hantush, M.M. )2007(. A probabilistic approach for analysis of uncertainty in the evaluation of watershed management practice. Journal of Hydrology, 333, 459-471.

[4] Azadnia, F., Rostami, N. and Kamali Moghaddam, R. )2009(. Comparison of empirical equations for estimating time of concentration of the basin Meimeh Ilam. Iranian Water Research Journal, 3(4), 1-8.

[5] Chin, D.A. )2000(. Water-resources engineering. Prentice Hall, New Jersey, 750p.

[6] Dastorani, M.T., Abdullah Wand, A., Talabi, A. and Moghadamnia, A.R. ) 2014(. Evaluate the use of empirical equations for estimating the focus time navigating time streams. Journal Research and development, 103(93), 1-8. In press.

[7] Dongquan, Z., Jining, C., Haozheng, W., Qingyuan, T., Shangbing, C. and Zheng, S. )2009(. GIS-based urban rainfall-runoff modeling using an automatic catchment-discretization approach, (Case study in Macau). Environ Earth Sci, 59, 465- 472.

[8] Eslamian, S. and Mehrabi, A. )2005(. Empirical relations for estimating the time of concentration mountainous watersheds. Journal of Natural Resources and Agricultural Sciences, 12, 36-45.

[9] Fang, X., Thompson, D.B., Cleveland, T.G., Pradhan, P. and Malla, R. )2008(. Time of concentration estimated using watershed parameters determined by automated and manual methods. Journal of Irrigation and Drainage Engineering, 134(2), 202-211.

[10] Green, J. and Nelson, E. )2002(. Calculation tim of Concentration for hydrologic design and analysis using geographic information system vector objects. Journal of Hydro informatics, 4, 75-81.

[11] Jamshidi, S. (2011). Compared to the estimated time of concentration using empirical relations (Case study: Watershed basin Srfyrvz Abad). 2th Geoscience Conference, 9p.

[12] Li, M.H., and Chibber, P. (2008). Overland flow time of concentration on very flat terrains. Transportation Research Record 2060. Transportation Research Board, Washington, DC, 133-140p.

[13] Mahdavi, M. (2011). Applied hydrology. 7ed Edition, Thesis. University of Tehran Press, 439p.

[14] McCuen, R. (1984). Eestimating urban time of concentration. Hydraulic Engineering ASCE, 100, 633-638.

[15] Mobaraki, J. (2006). Accuracy in the estimation of empirical relationships time to peak concentration Hydrograph (Case study: Tehran Province). MSc. Thesis. University of Tehran, 151p.

[16] Moghadamnia, A.R. (1997). A comparative study on the time-delay and time to reach peak flood hydrograph based on experimental methods and analysis of two regional climate. MSc. Thesis. University of Tarbiat Modarres, 163p.

[17] Motamedvaziri, B. (2004). Evaluation of some empirical relations to estimate the time of concentration (Case study: Karaj watershed). MSc. Thesis University of Tehran, 125p.

[18] Najafi, A. (2009). Factors of flood basin catchment Esfahan- Sirjan the factor analysis. Journal of Geography and Environmental Planning, 4, 101-118.

[19] Pavlovic, S.B. and Moglen, G.E. (2008). Discretization issues in travel time calculation. J. Hydrol. Eng., 13(2), 71-79.

[20] Shafai Bajestan, M. (2005). Principles and application of physical models – hydraulic, 1ed Edition, University of Martyr Chamran Press, 292p.

[21] Sharifi, S. and Hosseini, S.M. (2011) .Methodology for Identifying the Best Equations for Estimating the Time of Concentration of Watersheds in a Particular Region. Journal of Irrigation and Drainage Engineering, 137(11), 712-719.

[22] Sepahvand, A., Taei Semirom, M., Myrnya, Kh. and Moradi, H.R. (2011). Evaluate the model sensitivity to the variability of soil moisture. Journal of Soil and Water, 25(2), 338-346.

[23] Sourisseau, S.A., Basser, S.F. and Perie, T. (2007). Calibration, validation and sensitivity analysis of an ecosystem model applied to artificial streams. Water Research, 42, 1167-1181.

[24] Wong, T.S.W. (2005). Assessment of time of concentration formulas for overland flow. J. Irrig. Drain Eng., 131(4), 383-387.

[25] Wong, T.S.W. (2009). Evaluation of kinematic wave time of concentration formulas for overland flow. Journal of Hydraulic Engineering, 14(7), 739-744.

Journal of Range and Watershed Managment

Selection of the best empirical formula to estimate time of concentration in urban watersheds (Case study: Mahdasht town)

References

References

Volume 67, Issue 3 - Serial Number 3
December 2014
Pages 419-435

Selection of the best empirical formula to estimate time of concentration in urban watersheds (Case study: Mahdasht town)

References

References

Volume 67, Issue 3 - Serial Number 3December 2014Pages 419-435

Volume 67, Issue 3 - Serial Number 3
December 2014
Pages 419-435