Mighty Rio Grande Now a Trickle Under Siege

On maps, the mighty Rio Grande meanders 1,900 miles, from southern Colorado’s San Juan Mountains to the Gulf of Mexico. But on the ground, farms and cities drink all but a trickle before it reaches the canal that irrigates Bobby Skov’s farm outside El Paso, hundreds of miles from the gulf.

Now, shriveled by the historic drought that has consumed California and most of the Southwest, that trickle has become a moist breath.

“It’s been progressively worse” since the early 2000s, Mr. Skov said during a pickup-truck tour of his...