The Western Ghats plays a pivotal role in determining the hydrological and hydroclimatic regime of Peninsular India. The mountainous catchments of the Ghats are the primary contributors of flow in the rivers that sustains the life and agricultural productivity in the area. Although many studies have been conducted in the past decades to understand long term trends in the meteorological and hydrological variables of major river basins, not much attention have been made to unfold the relationship existing among rainfall and river hydrology of natural drainages on either side of the Western Ghats which host one of the unique biodiversity hotspots across the world. Therefore, an attempt has been made in this paper to examine the short term (last three decades) changes in the rainfall pattern and its influence on the hydrological characteristics of some of the important rivers draining the southern Western Ghats as a case study. The short term, annual and seasonal trends in the rainfall, and its variability and discharge were analyzed using Mann-Kendall test and Sen’s estimator of slope. The study showed a decreasing trend in rainfall in the southwest monsoon while a reverse trend is noticed in northeast monsoon. Correspondingly, the discharge of the west and east flowing rivers also showed a declining trend in the southwest monsoon season. The runoff coefficient also followed the trends in the discharge. The runoff coefficient of the Periyar river showed a decreasing trend, whereas the Cauvery river exhibited an increasing trend. A high-resolution analysis of rainfall data revealed that the number of moderate rainfall events showed a decreasing trend throughout the southern Western Ghats, whereas the high intensity rainfall events showed an opposite trend. The decline in groundwater level in the areas which recorded an increase in high intensity rainfall events and decrease in moderate rainfall events showed that the groundwater recharge process is significantly affected by changes in the rainfall pattern of the area.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Price includes VAT (USA)
Tax calculation will be finalised during checkout.
Bhutiyani, M.R., Kale, V.S. and Pawar, N.J. (2008) Changing streamflow patterns in the rivers of northwestern Himalaya: implications of global warming in the 20th century. Curr. Sci., v.95(5), pp.618–626.
Brown, A.E., Zhang, L., McMahon, T.A., Western, A.W. and Vertessy, R.A. (2005) A review of paired catchment studies for determining changes in water yield resulting from alterations in vegetation. Jour. Hydrol., v.310, pp.28–61.
Chen, Z., Chen, Y. and Li, B. (2013) Quantifying the effects of climate variability and human activities on runoff for Kaidu River Basin in arid region of northwest China. Theoretical and Applied Climatology, v.111(3), pp.537–545.
Dash, S.K., Kulkarni, M.A., Mohanty, U.C. and Prasad, K. (2009) Changes in the characteristics of rain events in India. Jour. Geophys. Res., v.114, D10109.
Ghosh, S., Luniya, V. and Gupta, A. (2009). Trend analysis of Indian summer monsoon rainfall at different spatial scales. Atmospheric Sci. Lett., v.10, pp.285–290.
Goswami, B.N., Venugopal, V., Sengupta, D., Madhusoodanam, M.S. and Xavier, P.K. (2006) Increasing trends of extreme rain events over India in a warming environment. Science, v.314, pp.1442–1445.
Govinda, R.P. (1995) Effect of climate change on stream flows in the Mahanadi river basin, India. Water Internat., v.20, pp.205–212.
Guhathakurta, P. and Rajeevan, M. (2008). Trends in the rainfall pattern over India. Internat.Jour. Climatol., v.28(11), pp.1453–1469.
Jain, S.K., Nayak, P.C., Kumar, Y.S.S. and Chandniha, S.K. (2017) Trends in rainfall and peak flows for some river basins in India. Curr. Sci., v.112(8), pp. 1712–1726.
Jasper, K., Calanca, P., Gyalistraus, D. and Fuhrer, J. (2004) Differential impacts of climate change on the hydrology of two alpine river basins. Climate Res., v.26, pp.113–129.
Jiang, S.H., Ren, L.L., Yong, B., Singh, V.P., Yang, X.L. and Yuan, F. (2011) Quantifying the effects of climate variability and human activities on runoff from the Laohahe basin in northern China using three different methods. Hydrological Process, v.25, pp.2492–2505.
IPCC (2007) Climate change 2007: The physical science basis. In: Solomon, S., Qin, D., Manning, M., Marquis, M., Averyt, K.B., Tignor. M., Miller, H. L., andChen, Z., (eds) Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge.
Kendall, M.G. (1975) Rank Correlation Methods. Griffin, London.
Kuhnel, I., McMohan, T.A., Finlayson, B.L., Haines, A., Whetton, P.H. and Gibson, T.T. (1990). Climatic influences on streamflow variability: A comparison between southeastern Australia and southern United States of America. Water Resour. Res., v.26, pp.2483–2496
Kumar, V., Jain, S.K. and Singh, Y. (2010a) Analysis of long-term rainfall trends in India. Hydrol. Sci. Jour., v.55(4), pp.484–496.
Kumar, V. and Jain, S.K. (2010b) Trends in rainfall amount and number of rainy days in river basins of India (1951–2004). Hydrol. Res., v.42(4), pp.290–306.
Lutz, S.R., Mallucci, S., Diamantini, E., Majone, B., Bellin, A. and Merz, R. (2016) Hydroclimatic and water quality trends across three Mediterranean river basins. Science of the Total Environment v.571, pp.1392–1406.
Ma, Z. M., Kang, S. Z., Zhang, L., Tong, L., and Su, X. L. (2008) Analysis of impacts of climate change and human activity on streamflow for a river basin in arid region of northwest China. Jour. Hydrol., v.352, pp.239–249.
Mann, H.B. (1945). Nonparametric tests against trend. Econometrica, v.13, pp.245–259.
Miao, C., Yang, L., Liu, B., Gao, Y. and Li, S. (2011). Streamflow changes and its influencing factors in the mainstream of the Songhua River basin, Northeast China over the past 50 years. Environ. Earth Sci., v.63, pp.489–499.
Milly, P.C.D., Dunne, K.A., Vecchia, A.V. (2005) Global pattern of trends in streamflow and water availability in a changing climate. Nature, v.438, pp.347–350.
Pai. D.S., Sridhar, L., Rajeevan, M., Sreejith, O.P., Satbhai, N.S. and Mukhopadhyay, B. (2014) Development of a new high spatial resolution (0.25×0.25 degree) long period (1901-2010) daily gridded rainfall data set over India and its comparison with existing data sets over the region, Mausam, pp.1–18.
Probst, J.I. and Tardy, Y. (1987). Long-range stream flow and world continental runoff fluctuations since the beginning of this century. Jour. Hydrol., v.94, pp.289–311.
Ramesh, K.V. and Goswami, P. (2007) The shrinking Indian summer monsoon. Research Report RR CM 0709, CSIR Centre for Mathematical Modelling and Computer Simulation, Bengaluru.
Ren, L.L., Wang, M.R., Li, C.H., Zhang, W. (2002) Impacts of human activity on river runoff in the northern area of China. Jour. Hydrol., v.261, pp.204–217.
Sen, P.K. (1968) Estimates of the regression coefficient based on Kendall’s tau. Jour. Amer. Statistical Assoc., v.63(324), pp.1379–1389.
Thomas, J. and Kumar, P. (2016) Temporal analysis of rainfall (1871-2012) and drought characteristics over a tropical monsoon-dominated state (Kerala), India. Jour. Hydrol., v.534, pp.266–280.
Vorosmarty, C.J., Green, P., Salisbury, J. and Lammers, R. (2000) Global water resources: vulnerability from climate change and population growth.
About this article
Cite this article
Sreelash, K., Sharma, R.K., Gayathri, J.A. et al. Impact of Rainfall Variability on River Hydrology: A Case Study of Southern Western Ghats, India. J Geol Soc India 92, 548–554 (2018). https://doi.org/10.1007/s12594-018-1065-9