Hiya.
A note inside this map: "NOTE: I posted request for use of this map at Filefront.unreal from Zen. Authors may NOT use any custom content in this map, including meshes, textures and sounds. You may NOT use this map as a base for other maps. You may not edit this map and then release the edited version."
Raj may or may not pay attention to this caveat by the map's author...
But btw, zombies can't swim and players would glitch in the water.