For starters your composition is good my only issue with the composition is I wish you hadn't lost the right end of the building, seems as though something was chopped off there.
Your lighting is good and you obviously took this at just the right time of day to avoid shadowing.
Now as graininess and meeting the challenge I seem some grain so you did well there.
Overall this is a beautiful scene and you captured it well.
OOH what a pretty setting. I like the reflection. The colors are beautiful. I don't see how there is much grain though.This might be cool in sepia too!