In days of yore, I called the waters by the name of Nara and because the waters have ever been my Ayana (abode), I am called Narayana.
अपां नारा इति पुरा संज्ञाकर्म कृतं मया। तेन नारायणोऽप्युक्तो मम तत् त्वयनं सदा॥