Based on a concept that originated int he late 19th century, Montana land use planner John Lavey has redrawn the boundaries of U.S. states based upon the location of major watersheds. Philly gets lumped into Delaware, whose boundaries are drawn around the Delaware River basin.
As the Washington Post's Reid Wilson summarizes the idea, "Sorting states by watersheds would force the individual states to make their own decisions balancing water usage, rather than fighting among themselves. And those states would be able to use water within their own boundaries, rather than shipping water tens, even hundreds of miles away."
Philly's new state--Delaware--is perhaps more clearly visible in this map.
Maps: John Lavey and Cameron Ellis/CommunityBuilders.net