Ganesha's clay image signifies the Prithivi Thathvam. Prithivi is one of the five mahabuthas and a repository of senses of sabda, sparsa, rupa, resa and gandha. Throwing the Ganesha images in water and disintegrating them is symbolical of the disintegration of the mind from the object of senses and enlighting it to merit higher spiritual elevations indicated by Mahalaya amavasi, Navaratri, Vijaya dasam and Deepavali festivals.