Water bottles of the sort carried by people illegally crossing the border lie in the desert just north of the new border wall in Sasabe.
The U.S. Border Patrol in southern Arizona is warning of the dangers that border crossers face as summer temperatures soar into triple digits.
The Border Patrol's Tucson Sector said Thursday that migrants are putting their lives at risk when they cross the Sonoran Desert. It notes that adults traversing that area in the current heat must consume daily at least two gallons (7.5 liters) of water to survive.
An excessive heat warning for many parts of southern and central Arizona is expected to begin on Saturday and stretch at least until June 18, with a potential high of 117 F on Wednesday.
The border officials say migrants who get lost in the desert should use their cell phones to call 911.
Rescues of migrants are already up this year, including a group of 26 migrants found stranded in Arizona borderlands near Gila Bend last week.
Last week, Border Patrol agents in the Yuma Sector to the west found the remains of two migrants who died in separate locations: a 40-year-old Mexican man and a 20-year-old Guatemalan woman.