as california struggles with a devastating drought , huge amounts of water are mysteriously vanishing from the sacramento-san joaquin delta .
the prime suspects are farmers whose families have tilled fertile soil there for generations .
delta farmers say they 're not stealing it because their history of living at the water 's edge gives them that right .
california 's water rights system has historically given senior water rights holders the ability to use as much water as they need , even in drought .
gov. jerry brown has said that if drought continues this system built into california 's legal framework could be changed .