Srimad Bhagavatam Canto 11, Chapter 31, Text 23

SB 11.31.23

dvarakam harina tyaktam
 samudro ’plavayat ksanat
varjayitva maha-raja
As soon as Dvaraka was abandoned by the Supreme Personality of Godhead, the ocean flooded it on all sides, O King, sparing only His palace.
Srila Jiva Gosvami explains that whereas the external manifestation of the Lord’s abode was covered by the ocean, the Lord’s eternal Dvaraka exists beyond the material universe and certainly beyond the material ocean. Dvaraka had been constructed by Visvakarma, the architect of the demigods, and the Sudharma assembly hall had been brought from heaven. In that city there were many beautiful and splendorous residences of the aristocratic Yadu dynasty, and the most beautiful residence of all was that of the Supreme Personality of Godhead. Srila Jiva Gosvami mentions that even in the modern age, people who live near the site of the original Dvaraka sometimes catch a glimpse of it in the ocean. Ultimately, the Lord’s associates and abode are eternal, and one who understands this is qualified to become fully Krsna conscious.
Srimad Bhagavatam Canto 11, Chapter 31, Text 22
Srimad Bhagavatam Canto 11, Chapter 31, Text 24