GEOGRAFIA Online TM Malaysian Journal of Society and Space 12 issue 6 (126 - 141) 126 Themed issue on current social, economic, cultural and spatial dynamics of Malaysia’s transformation © 2016, ISSN 2180-2491 Accelerated development and changes in rainfall trends and variations in Malaysia: A case study of the Kinta River basin 1960- 2006 Mohmadisa Hashim 1 , Wan Ruslan Ismail 2 , Zullyadini A. Rahaman 1 , Nasir Nayan 1 , Zainudin Othman 1 , Yazid Saleh 1 1 Department of Geography & Environment, Faculty of Human Sciences, Universiti Pendidikan Sultan Idris, Tanjong Malim, 35900 Perak, Malaysia, 2 Hydro Geomorphology Research Group, Research Center for Environment, Society and Space (RECESS), School of Humanities, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia . Correspondence: Mohmadisa Hashim (email: mohmadisa@fsk.upsi.edu.my) Abstract Environmental impact induced by rapid urbanization and development may be traced from changes in local rainfall trends and variations. This study examined the trends and variations of rainfall in the Kinta River basin, Perak, a region in Malaysia that is rapidly urbanizing and developing. Long-term rainfall data from the year 1960 to 2006 were obtained from the Department of Irrigation and Drainage (DID) involving 15 rainfall stations in the Kinta River basin were employed to analyse long-term variations and precipitation trends. Results of the Mann-Kendall tests show that the Kinta River basin received high rainfall during the Northeast monsoon (950 mm) as compared to that received during the Southwest monsoon (309 mm). The tests also showed that the annual rainfall in the Kinta River basin had an increasing trend from the year 1960-2006 with the value of S=217 as did the monthly rainfall (except in the months of June and July 8) and seasonal rainfall during Northeast monsoon (S = 216) and Southwest monsoon (S = 97). These trends of increasing rainfall appeared to give the early impression that the basin should not have any problems with regard to water supply, in particular, for the purpose of agricultural irrigation and domestic use. However, careful planning should still be undertaken in view of the rapid development of the basin due to rapid urbanisation of the areas surrounding the Ipoh City as there will certainly be growing demand for water in this area in the near future. Keywords: accelerated development, environmental impact, Mann-Kendall test, Kinta River basin, rainfall trends and variations, rapid urbanisation Introduction Rainfall is one of the important hydrological aspects to be studied in the context of a drainage basin. Some features of the rainfall often studied are such as quantity, frequency, distribution, heaviness and rainfall periods (Wan Ruslan, 1994). Variations of rainfall give a very unique perspective about the rainfall condition, especially in tropical areas. In Malaysia, the government agency leading the observation of rainfall data is Malaysian Meteorological Department (MMD) and the Department of Irrigation and Drainage (DID). For the state of Perak alone there are 108 rainfall stations monitored by DID located either in the estate, government offices such as police stations, municipalities, schools and other establishments (DID, 2007). The trend analysis is a tool or method used to understand variations of a variable over a series of time data. The trend analysis will be able to identify and detect a change and the change is actually occurring in the context of space and time. The trend analysis requires data or information in a long run According