 The Canning Dam and reservoir still supplies approximately 20 percent of Perth 's drinking water requirements and plays an important role in the context of the development of Perth . 
 The Canning Dam and reservoir still <a href='uninflect' title='1'><mark>supplies</mark></a> approximately 20 percent of Perth <a href='null_genetive' title='2'><mark>'s</mark></a>drinking water requirements and <a href='uninflect' title='3'><mark>plays</mark></a> an important role in the context of the development of Perth . 
The Canning Dam and reservoir still supply approximately 20 percent of Perth  drinkin water requirements and play an important role in da context of the development of Perth .