Complex sentence: The estuary, which had been closed to navegation since the early modern era, was partially drained and cleared in the 19th century, and the water inlet dividing the place covered, so the two parts, Sabugo and La Villa, joined together.
Split into simpler sentences: The estuary, which had been closed to navigation since the early modern era, was partially drained and cleared in the 19th century. The water inlet dividing the place was covered, so that the two parts, Sabugo and La Villa, could be joined together.