Observation Garden Bridge Design
This is a great idea for making a garden pond bridge even more functional than a passage over a pond or stream. You'll hear myself and other designers talk about creating different rooms in gardens and landscapes. While this may not be considered your typical garden room, I think the seating area on a bridge in the middle of a pond qualifies as a unique and inviting isolated area of the yard.
Not necessarily a private area, the deck with table and chairs is still quite secluded with a percieved sense of privacy. It's areas like this covered seating area over this garden pond bridge that become the most used areas of the yard for relaxing, contemplating, and intimate quiet conversations.