@mickEblu and
@Bandini, there is a moat. The bridge over the moat is behind the castle forecourt stage. It's a shorter bridge than Sleeping Beauty Castle's, and there is no drawbridge, but it does cross over water. The waterway extends around to Tomorrowland and Liberty Square, and all the way into Adventureland, looping around Swiss Family Treehouse. The waterway completely encircled the hub before the recent overhaul that filled in the stretch just along the front of Main Street USA. At one time, "Plaza Swan Boats" navigated this waterway, including crossing under the bridge to Cinderella Castle.
Because it is farther down in elevation from the walkways, it's not as noticeable from certain angles, like right in front of the Castle forecourt. But from other angles it's very impressive.
And as for accessing the bridge over the moat, like Bandini said, it's sadly blocked for long stretches during the day for the castle shows.