Assessment of the Effects of Temperature and Precipitation Variations on the Trend of River Flows in Urmia Lake Watershed

Document Type : Research Paper


1 Ph.D. Student- Tarbiat Modares University

2 Tarbiat Modares University


Trend analysis is one of the appropriate methods to assess the hydro-climatic condition of watersheds, which is commonly used for analysis of change pattern in a single variable over time. However, in real cases, many hydrological variables such as river flow are directly affected by climate and environmental factors, which usually go unnoticed in routine analyzes. The aim of the present research is to investigate the trend of river discharge in 25 hydrometric stations in Lake Urmia river basin with and without consideration of temperature and rainfall variability. Briefly, the results showed that there is a decreasing trend in all stations, which is significant in 9 cases. Also, it has been shown that regarding to trends in precipitation and temperature, the number of stations with significant decreasing trend will reduce to 7, which shows low impact of climate factors on the reduction rate of discharge in these stations. Based on the results, it can be concluded that climate variations have direct effect in inferring significant trends in river flow, so that considering these variables in studying of river discharge can lead to different results in the detection of significant trends.


1- Fathian, F. (2012). “Assessment of land use changes using remote sensing techniques and hydroclimatic variable trends of Urmia river basin.” M.Sc. Thesis, Tarbiat Modares University (In Persian).
2- Chandler, R. E., and Scott, E. M. (2012). Statistical methods for trend detection and analysis in the environmental sciences, John Wiley and Sons, West Sussex, UK.
3- Xiong, L. and Guo, S. (2004). “Trend test and change-point detection for the annual discharge series of the Yangtze river at the Yichang hydrological station.” Hydrological Sciences Journal, 49(1), 99-112.
4- Kundzewicz, Z. W., and Robson, A. J. (2004). “Change detection in hydrological records—a review of the methodology.” Hydrological Sciences Journal, 49(1), 7-19.
5- Kundzewicz, Z. W., and Robson, A. J. (2000). Detecting trend and other changes in hydrological data, World Climate Program-Data and Monitoring, Geneva, 158.
6- Xu, Z. X., Takeuchi, K., and Ishidaira, H. (2003). “Monotonic trend and step changes in Japanese precipitation.” J. of Hydrology, 279(1-4), 144-150.
7- Wang, W., Shao, Q., Peng, S., Zhang, Z., Xing, W., An, G., and Yong, B. (2011). “Spatial and temporal characteristics of changes in precipitation during 1957-2007 in the Haihe River basin, China.” Stochastic Environmental Research and Risk Assessment, 25(7), 881-895.
8- Khaliq, M. N., Ouarda, T. B. M. J., Gachon, P., Sushama, L., and St-Hilaire, A. (2009). “Identification of hydrological trends in the presence of serial and cross correlations: A review of selected methods and their application to annual flow regimes of Canadian rivers.” J. of Hydrology, 368(1-4), 117-130.
9- Mavromatis, T., and Stathis, D. (2011). “Response of the water balance in Greece to temperature and precipitation trends.” Theoretical and Applied Climatology, 104 (1-2), 13-24.
10- Kahya, E., and Kalayc─▒, S. (2004). “Trend analysis of streamflow in Turkey.” J. of Hydrology, 289(1-4), 128-144.
11- Libiseller, C. (2004). “Comparison of methods for normalisation and trend testing of water quality data.” 15th Annual Conference of The International Environmetrics Society, Portland, USA.
12- Libiseller, C., and Grimvall, A. (2002). “Performance of partial Mann–Kendall tests for trend detection in the presence of covariates.” Environmetrics, 13(1), 71-84.
13- Smith, E. P., and Rose, K. A. (1991). “Trend detection in the presence of covariates: Stagewise versus multiple regression.” Environmetrics, 2(2), 153-168.
14- Pettitt, A. N. (1979). “A Non-parametric approach to the change-point problem.” J. of the Royal Statistical Society. Series C (Applied Statistics), 28(2), 126-135.
15- Taylor, W. (2000). Change-Point Analyzer 2.0 shareware program, Taylor Enterprises, Libertyville, Illinois.
16- Love, D., Uhlenbrook, S., Twomlow, S., and Zaag, P. V. D. (2010). “Changing hydroclimatic and discharge patterns in the northern Limpopo Basin, Zimbabwe.” Water SA., 36, 335-350.
17- Fathian, F., and Morid, S. (2012). “Study of climate and hydrologic trends in Lake Urmia watershed using non-parametric methods.” Iranian Journal of Soil and Water Research, 43(3), 259-269. (In Persian).
18- Delju, A. H., Ceylan, A., Piguet, E., and Rebetez, M. (2013). “Observed climate variability and change in Urmia Lake Basin, Iran.” Theoretical and Applied Climatology, 111, 285-296.
19- Hamed, K. H., and Rao, A. R. (1998). “A modified Mann-Kendall trend test for autocorrelated data.” J. of Hydrology, 204(1-4), 182-196.
20- Mann, H. B. (1945). “Nonparametric tests against trend.” Econometrica, 13(3), 245-259.
21- Kendall, M. G. (1948). Rank correlation methods, Charles Griffin, London.
22- WMO. (1966). Climatic Change, WMO Technical Note No. 79, 79 pp.
23- Dahmen, E. R., and Hall, M. J. (1990). Screening of hydrological data, Netherlands, 58 pp.