Document Type : Research Paper


1 M.Sc. Student, Department of Arid and Mountain Reclamation Engineering, Faculty of Natural Resources, University of Tehran, Karaj, Iran

2 Professor, Department of Arid and Mountain Reclamation Engineering, Faculty of Natural Resources, University of Tehran, Karaj, Iran

3 Assoc. Professor, Department of Arid and Mountain Reclamation Engineering, Faculty of Natural Resources, University of Tehran, Karaj, Iran

4 Assist. Professor, Institute of Agricultural Education & Extension, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran


The purpose of this study was to investigate the trend of hydro-climatic variables, detect the occurrence of climate change and subscale the climatic variables during future periods and evaluate the intensity and magnitude of future floods. The trend of hydroclimatic variables was first investigated using Mann-Kendall and Sen tests. Then, the output data of maximum temperature, minimum temperature and precipitation of CANESM2 general circulation model were sub-scaled under RCP2.6 and RCP8.5 climate change scenarios using SDSM 4.2.9 model. Later, HEC-HMS model was used to evaluate the intensity and magnitude of events in the Emameh watershed in future periods. The results showed that 20.8 and 14.6% of the maximum temperature and minimum temperature series had a significant upward trend. While 5.5% of the rainfall time series had a significant upward trend. Therefore, unlike the temperature variable, the monthly precipitation variable did not have a definite trend during the observation period as in future periods, in some months it showed an increasing trend and in some months it showed a decreasing trend. However, the maximum and minimum temperatures under the diffusion scenarios increased in the following periods. The peak flow and volume ​​of the simulated floods, under the most severe events in each period, was significantly smaller for future periods than for the observation period. Comparison of the most severe events with each other in different periods showed an increase in the volume and magnitude of the flood in the RCP2.6 scenario compared with RCP8.5. Therefore, in the context of climate change, the number of floods and their destructive power has increased and managers and planners are recommended to pay attention to this, especially in urban areas.


Main Subjects

Akhtar, M., Ahmad, N. and Booij, M. J. (2008). The impact of climate change on the water resources of Hindukush–Karakorum–Himalaya region under different glacier coverage scenarios. J. Hydrol., 355(1-4), 148-163.
Alipour, H. and Malekian, A. (2017). Analyzing of trend changes in the frost threshold (Case Study: Northwest of Iran). Nat. Environ. Hazard., 7 (17), 69-82 [In Persian].
Ansari, M., Noori, G. and Fotoohi, S. (2016). Investigation of temperature, precipitation and flow changes using non-parametric Mann-Kendall test (Case study: Kajo river basin of Sistan and Baluchestan province). J. Watershed Manage., 7(14), 152-158 [In Persian].
Ashofteh, P. and Massah Bavani, A. (2010). The impact of climate change on maximum discharge: case study, Aidoghmoush Basin, East Azerbaijan. J. Water Soil Sci., 14(53), 28-38 [In Persian].
Dastrang, A. (2012). Prediction of temperature and precipitation using general circulation models of climate simulation atmosphere (study area of the northern provinces of the country). Master Dissertation, University of Tehran, Karaj, Iran. 150 p [In Persian].
Dibike, Y. B. and Coulibaly, P. (2005). Hydrologic impact of climate change in the Saguenay watershed: comparison of downscaling methods and hydrologic models. J.Hydrol., 307(1-4), 145-163.
Dodangeh, I., Soltani, S. and Sarhaddi, A. (2010). Study of the trend of flow limit values (minimum flow and flood) in the Sefidrud dam watershed. J. Water Soil Sci., 15(58), 215-229 [In Persian].
Fathian, F., Morid, S. and Kahya, E. (2015). Identification of trends in hydrological and climatic variables in Urmia Lake basin, Iran. Theor. Appl. Climat., 119(3-4), 443-464.
Hejazizadeh, Z., Fattahi, A., Massah Bavani, A. and Naserzadeh, M. (2012). Consider impact of climate changes on floods by using the atmospheric circulation model (AOGCM). Geogr., 10(34), 5-24 [In Persian].
Hojjam, S., Khoshkhar, Y. and Shamsodinvand, Y. (2008). Analysis of the trend of seasonal and annual rainfall changes in some selected stations in the central part of Iran using unchanged methods. Geogra. Res., 40 (64), 157-168. [In Persian].
Kendall, M.G., (1975).  Rank Correlation Methods; Griffin: London, UK.
Kisi, O. (2015). An innovative method for trend analysis of monthly pan evaporations. J. Hydrol., 527, 1123- 1129.
Liu, P., Li, L., Guo, S., Xiong, L., Zhang, W., Zhang, J. and Xu, C. Y. (2015). Optimal design of seasonal flood limited water levels and its application for the Three Gorges Reservoir. J. Hydrol., 527, 1045-1053.
Maghsood, F. F., Moradi, H., Bavani, M., Reza, A., Panahi, M., Berndtsson, R. and Hashemi, H. (2019). Climate change impact on flood frequency and source area in northern Iran under CMIP5 Scenarios. Water, 11(2), 273.
Mann, H. B. (1945). Nonparametric tests against trend. Econom., 13, 245–259.
Maslin, M. (2014). Climate Change: A Very Short Introduction (Third edition), Oxford Press, 200pp.
Massah Bavani, A. and Morid, S. (2005). The effects of climate change on water resources and agricultural production Case study: Zayandehrud basin of Isfahan. Iran. Water Resour. Res., 1(1), 40-47 [In Persian].
Nassaji Zavareh, M., Khorshid Dost, A. M., Rasoli, A. A. and Salajegheh, A. (2014). Investigation of discharge trend of Kasilian river. Iran. Watershed Manage. Assoc., 24(8), 1-8 [In Persian].
Partal, T. and Kahya, E. (2006). Trend analysis in Turkish precipitation data. Hydrol.  Process. Int. J., 20(9), 2011-2026.
Pierrehumbert, R. T. (2010). Principles of planetary climate. Cambridge University Press.
Sen, Z. (2012). Innovative trend analysis methodology. J. Hydrol. Eng., 17(9), 1042–1046.
Sen, Z. (2014). Trend identification simulation and application. J. Hydrol. Eng., 19(3),635–642.
Sharifi, A., Din Paghoh, Y., Fakheri Fard, A. and Moghaddam Nia, A. (2013). Optimal combination of variables for simulation of runoff in Imameh watershed using gamma test. Water Soil Know., 23(4), 59-72 [In Persian].
Tosunoglu, F. and Kisi, O. (2016). Trend Analysis of maximum hydrologic drought variables using Mann–Kendall and Şen's innovative trend method. River Res. Appl., 33(4), 597-610. DOI: 10.1002/rra.3106.
Zare Zadeh, Sh., Khorani, A., Bazrafshan, J. and Bazrafshan, O. (2018) Gamasiab river flow regime changes under climate change scenarios. J. Environ. Sci., 4(44), 587-602 [In Persian].
Zhang, Y., Guan, D., Jin, C., Wang, A., Wu, J. and Yuan, F. (2011). Analysis of impacts of climate variability and human activity on streamflow for a river basin in northeast China. J. Hydrol., 410(3-4), 239-247.