In portions of its length, the Charles drops slowly in elevation and has relatively little current. Despite this, early settlers in Dedham, Massachusetts, found a way to use the Charles to power mills. In 1639, the town dug a canal from the Charles to a nearby brook that drained to the Neponset River. By this action, a portion of the Charles's flow was diverted, providing enough current for several mills. The new canal and the brook together are now called Mother Brook. The canal is regarded as the first industrial canal in North America. It remains in use for flood control.