I'm going to write this up more formally for my blog, but I was reading the Blessings and Curses mini-supplement this week even as I was teaching Wizard of Earthsea in my fantasy lit course, and I suddenly began imagining the following passage in LoG&S fashion:
"[Ged] set a charm on that salty unreliable spring. The water rose up through the sand as sweet and clear as any mountain spring in the heights of Gont, nor did it ever fail.""
Let's see ... Severity is Mild (1 pt., it's just a desalination charm on a spring), Influence is Specific (1 pt., a single spring on a tiny island), Ongoing (4 pts., the water is always fresh to drink), Dismissal Requires Effort (2 pts., Ged's pretty powerful so it wouldn't be just any run-of-the-mill Roke graduate who could dismiss the spell), and Duration is Generational (x4, it's going to be around for centuries).
That's a total blessing cost of 32, which seems like a lot. But I thought this could be a starting point for discussion.
(Also, gamers are sick people, reading fiction and translating it into mechanics.)