Srimad Bhagavatam Canto 05, Chapter 16, Text 19

SB 5.16.19

evam jambu-phalanam atyucca-nipata-visirnanam anasthi-prayanam ibha-kaya-nibhanam rasena jambu nama nadi meru-mandara-sikharad ayuta-yojanad avani-tale nipatanti daksinenatmanam yavad ilavrtam upasyandayati.
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Similarly, the fruits of the jambu tree, which are full of pulp and have very small seeds, fall from a great height and break to pieces. Those fruits are the size of elephants, and the juice gliding from them becomes a river named Jambu-nadi. This river falls a distance of 10,000 yojanas, from the summit of Merumandara to the southern side of Ilavrta, and floods the entire land of Ilavrta with juice.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
We can only imagine how much juice there might be in a fruit that is the size of an elephant but has a very tiny seed. Naturally the juice from the broken jambu fruits forms waterfalls and floods the entire land of Ilavrta. That juice produces an immense quantity of gold, as will be explained in the next verses.
Srimad Bhagavatam Canto 05, Chapter 16, Text 18
Srimad Bhagavatam Canto 05, Chapter 16, Text 20-21