The Great Breach
The only record which survives of large-scale engineering before the arrival of the Portuguese is that of the remnants of a massive stone causeway across the Flats on the island of Bombay. These Flats were the low-lying lands between Dongri and Malabar hills, seperated from the island of Worli by the Great Breach, through which the sea poured in at high tide.
Pydhonie and Umarkhadi
The Great Breach may have extended almost to Umarkhadi, the creek seperating Bombay from Mazagaon. Occasionally the two would be linked by a shallow creek at the site of the crowded present-day bazaar area of Pydhonie. Only the name, which means "foot wash", now gives a clue to the fact that it was once a creek, because this was probably the first piece of land to be reclaimed from the sea.
Quite as likely, Umarkhadi was also filled in soon after the arrival of the British and joined Mazagaon irretrievably to Bombay. The last story in which Mazagaon appears as a seperate island relates to its occupation by the Sidi of Janjira in 1690-1. He was repelled by a rag-tag navy of fishermen led by the amateur Parsi admiral Rustomji Dorabji.
The Hornby Vellard
Early efforts at land reclamation concentrated on the small creeks crossing the northern Flats of Bombay island. Several of these were dammed or filled in during the eighteenth century. As a result, the areas north and east of Umarkhadi andMazagaon were slowly settled in this period. However, the next major reclamation was due to the closure of the Great Breach north of Cumballa Hill in 1784 by the building of a sea-wall called the Hornby Vellard. The wall allowed reclamation of the Flats and supplied about 400 acres of land for the extension of the crowded inner city. The precincts of Mahalaxmi,Kamathipura, Tardeo and parts of Bycullah were settled.