Awash

Awash is a Halo 2: Anniversary multiplayer map intended for use as a Forge canvas. It is one of three skybox-only maps created for Forging; the playable area consists solely of an expanse of shallow water, with a number of inaccessible islands in the distance. Unlike previous Forge canvases featuring water such as Forge World and Forge Island, Awash's water is shallow enough to allow players and vehicles to walk or drive in without dying due to kill boundaries.

Trivia
It is possible to exit the boundaries of the map and even build off map with a glitch.