The drought drags on, and the thirsty residents of Southern California are preparing again to spend heavily to buy water from the farm fields of the Sacramento Valley.

The board of the Metropolitan Water District of Southern California directed its staff Tuesday to start negotiating the purchases of as much as 100,000 acre-feet of water from the Valley — deals that would be worth millions of dollars.

Metropolitan has bought water from Northern California in eight of the past 16 years. The purchases can be a sensitive point in farm country, where water sales will result in fewer acres of crop grown and damage done to the local economy.