Maeda Toshiie and his successors greatly enlarged Kanazawa Castle and carefully planned the layout of the surrounding jōkamachi to meet strategic and defensive concerns. On April 14, 1631, a fire consumed much of the city, including the castle. In 1632 Maeda Toshitsune ordered the construction of a canal to bring water from the upper Sai River to the castle to alleviate a water shortage problem. Water was drawn from far upstream, and channeled through kilometres of canals and pipes carefully laid at a 750:1 slope for about to the castle. The water was fed to the castle under the moat that lay between it and what is now Kenrokuen by an artesian well. The large lake in Kenrokuen, Kasumi-ga-Ike, acted as an emergency supply. Local legend has it that the lake has a plug, which could be pulled to increase the water in the moats. The series of moats were laid out in the early seventeenth century. Initially they were dry, but later connected to the rivers. The Inner Moat was dug in only 27 days, and averaged about four to five feet wide. The Outer Moat took a bit longer, and averages some six to nine feet in width. Though much of the Inner Moat has been filled in, large sections of the Outer Moat remain. The earth removed from the moat was piled into ridges along the inner side, as an added defence measure.