Six years later, in 1610 Rowland published a book describing the system, "Most Approved and Long experienced Water Workes containing The manner of Winter and Summer drowning". In it he claimed that the Trench Royal was navigable, and was being used to ship goods from one end of the estate to the other. The book also claimed they built up the area, including a mill and up to 2,000 workers. If these accounts are true, no trace of their houses remains.