The old climate change, page-55

a) it isn't a 'temple' but an icon niche in the rock
b) its on an island that is submerged during flood times
c) its a religious practice and not really consistent with buddhism. religious practices don't need reason.
d) have you actually seen the images of the icon? the rock in which its built is very hard.... if you look you'll notice there is barely any erosion from water. the rock is hard lava flow, probably dinosaur era. religious love to achieve the very difficult as a mark of their devotion. so they spent a long time working on this island in the Yangtze River, probably more than 12 months during seasons of low flow, hollowing out this niche and leaving the buddha.
e) reportage has manipulated the images to make out that the icon is always covered but the lack of erosion shows that its rarely been washed over by water.