The river is 17 kilometres (11 mi) long. Its name is derived from iep, the Dutch word for elm. It gave its name to the city of Ieper. In the 11th century the river was canalized to link the city, which had a thriving cloth industry, to the sea. Even in 1842, some 2034 boats still passed the lock at Boezinge. Today, the canal is only used for recreational purposes.