Authorities in California's Fresno County have seized $1 billion worth of marijuana plants from pot farms discovered in the Sierra Mountains the past week.

A Wednesday press release by Fresno County said authorities also arrested 82 Mexicans acting as caretakers of the farms during the Operation Save Our Sierra. The massive operation aims to remove marijuana plantations in the Sierra Mountains operated by Mexican drug cartels.

Authorities said Mexican drug cartels have picked the areas for planting marijuana, growing the farm through an elaborate watering system that source water from streams, rivers and lakes.

Since the operation started in February, authorities have found dozens of marijuana plantations and arrested their Mexican growers. The operation will continue seizing 70 identified marijuana plantations until November.