Fig. 9—Map showing shoals in Tennessee River near Florence.
“From Brown’s Ferry to the mouth of Elk river the fall is twenty-six feet in eleven miles. This is known as ‘Elk River Shoals.’ Its most precipitous part is at the lower end, where there is a fall of 16.5 feet in about four miles.
“From the mouth of Elk river to the head of Mussel Shoals, a distance of five miles, there is a fall of only two feet.
“From the head of Mussel Shoals to Bainbridge the fall is eighty-five feet in seventeen miles, and is known as ‘Mussel Shoals.’
“From Bainbridge to Florence the fall is twenty-three feet in seven miles, and is known as ‘Little Mussel Shoals.’
“From Florence to the head of Colbert Shoals the fall is three feet in eleven miles.
“From the head of Colbert Shoals to Waterloo is, therefore, 160 feet in a distance of fifty-seven miles. Sixteen miles of the distance, however, has a fall of only five feet, leaving a fall of 155 feet in forty-one miles that cover the four shoals mentioned. The shoals are really more precipitous than the foregoing figures would indicate. For instance, 84.6 feet of the fall at Mussel Shoals is in a distance of fourteen miles.”
The general surface of the water on these shoals is comparatively smooth and of even depth in its levels across the river, with no deep fissures to interfere with the building of dams at any location that may be selected. The islets and projecting rocks can be taken into the structure of the dams at a considerable advantage in the cost of such works.
The bed and banks of the river are only subject to slight changes, and improvements, when made, are therefore practically permanent.