Good example of large water feature in an alpine setting done well. Stones and boulders should be of the same rock type/color and weathering, and be planted in such a way as to suggest they are the weathered portion of a massive formation just below. This is especially true with water features, since rock is always exposed by the erosion of water courses.
I like the idea of using corrugated roof with clear - so light can get in... but I guess it will depend on what material it is? I am happy to clean it every so often - but will need a ladder!! Like this shape and simplicity..
Architecture is creativity solidified into a form of building..."the complex or carefully designed structure of something" (Google def #2). NOT necessarily as large as "a building". Here is a half-circle of stones built to rise in an arch at the still water's edge. The waters reflect it to create a perfect circle, and the stones below the water parallel the form of the stones. Martin Hill Stream Stone Circle, White Beach, New Zealand