I think the dome on the photo above is the hot spring bathroom of the hotel. Because of the existence of the backyard, the scenery of the creek can be seen from the outside bath of the hot spring spa.
Why ? The naked people enjoying bathing outside the building should hide from the trekkers.
I could not find the traces of flood but the width of the creek seemed to have changed sometimes. The water flow was so close to the hotel but the forest in the valley seemed to adjust the amount of water flowing into the creek.