Extended Abstract

According the analy sis of rainfall trends for the pe riod 1951-2008, it was clear that, there is apossibility to shift climate zones during recent past. As mentioned earlier ther e are three climatezones in Sri Lanka nam ely Dry zone (average rainfall below 175 0 mm per annum), IntermediateZone (average rainfall betw een 1750 mm and 2500 m m per annum), Wet Zone (average rainfallabove 250 0 m m per annum). Average rainfall for the periods 1961-1990 and 1975-2004were calculated and it shows that the margin of the different climate zones are slightl y shrinkingduring the recent season (1975-2004 ) (Figure 4).Figure 4 : Rainfall map for the Periods (a) 1961-1990 and (b) 1975-2004Other im pact for the recharge of grou nd water is the heavy rainfall and high intense rainfall.Recent analysis for the period 1961-2008, shows that one day heavy rainfall has been increased inthe western slopes (Figure 5) (Prem alal, 2008). The am ount of annual rainfall is high in thewestern slop e and hence amount of runoff will in crease due to the High intensities. Thereforeboth the heavy rainfall and increasing evaporation due to high temperature is highly impacted forthe ground water recharge. Analysis of annual rainfall shows that the total annual rainfall amountis decreasing by about 8 m m per year. Therefore it can be shown that the water sector is muchvulnerable for the climate change.-265-