Aparānta The Western End

Thus we can safely conclude that Konkan and Aparanta were geographically distant; they belonged to two different eco-zones : Aparanta was a sea fronting alluvial plain nourished by Saraswati river then flowing with full vigour, endowed with some excellent ports and enriched with a flourishing domestic and overseas trade; Konkan was largely covered by a tropical forest, extending from a newly inhabited coastal plain to somewhere in the Deccan plateau across the Sahyadri; then how did Aparanta come to be associated with Konkan ?