This yellow bloom is an Indian Pond Lily. The tall leaves coming up from the pond belong to this plant. The flat lily pads are from the wild water lilies.
Exploring rural Oregon, this southern Californian was amazed and excited to see so many creeks, streams, rivers, ponds and lakes. Several ponds I passed were filled with masses of wild water lilies. i finally found one that I could park near and shoot. It had white and pink lilies, as well as yellow Indian Pond Lilies.
This view of the pond lily show the interesting interior of the flower, as it rests on one of its leaves.