The Ogallala Aquifer: A Modern-Day MacGuffin

Link here.

This describes the Ogallala reservoir perfectly as it relates to the Keystone:

A MacGuffin (sometimes McGuffin or maguffin) is "a plot element that catches the viewers' attention or drives the plot of a work of fiction." The defining aspect of a MacGuffin is that the major players in the story are (at least initially) willing to do and sacrifice almost anything to obtain it, regardless of what the MacGuffin actually is. In fact, the specific nature of the MacGuffin may be ambiguous, undefined, generic, left open to interpretation or otherwise completely unimportant to the plot. Common examples are aquifers, money, victory, glory, survival, a source of power, a potential threat, or it may simply be something entirely unexplained.

Okay, you caught me. I added "aquifers" to the paragraph above.