When construction of the early-period castle town was progressing, a water network was put into operation that originated from the ponds within Minato City area. Later, as the castle town expanded, proper waterways became necessary, and the Tamagawa Waterworks were completed in 1654. After this, repeated preservation and repair works were carried out to maintain this important base of the city. Here we witness a management system led by the Shogunate that brought together improvements in drainpipes and drainage basins that used Japanese boat-building technology, and high-level civil engineering technology for securing such apparatus in place.