St. Anthony Falls

St. Anthony Falls was formerly one of the largest natural waterfalls by volume in the United States. The falls are thought to have dropped between 20 and 50 feet over a weak layer of quickly eroding limestone caprock, which resulted in the falls rapidly retreating upstream, estimated at as much as 4 feet per year up until the 1870s. By the late 19th century the site had been heavily industrialized with Mills and power plants. Because of the instability of the cliff which formed the falls, following a significant collapse of the limestone caprock where a tunnel had been dug for a diversion channel for a power station, a dam was constructed upstream of the falls to divert the river away from the natural cliff. The natural falls were eventually replaced with a concrete apron to shore up the unstable cliff face. In 1956 the current Lower St. Anthony Falls Dam was completed, and eight years later the upper dam and corresponding Locks followed. No part of the natural St Anthonys Falls remains today, and even if both dams were removed it?s not clear how much of the falls would be possible to restore given all of the altercations which have taken place over the years.