LESSONS FROM OHIO RESERVOIRS
MORRIS KNOWLES
Pittsburgh Flood Commission
Early reports of the recent Ohio floods gave many the impression that the disasters were due to the failure of reservoirs; and as these reports were not generally corrected later, this impression no doubt remains in the minds of some. An investigation made during the week following the disasters showed this to be incorrect; but the escape was so narrow in some instances that the lesson of reservoirs of this sort is driven home almost as strongly as if they had failed and caused an enormous destruction of life and property.
Most of the reservoirs in the flooded districts belonged to the Ohio state canal system and were constructed to supply water for the canals in the dry seasons. In addition, the Columbus water supply storage dam on the Scioto river, was reported to have failed, causing a panic in Columbus. A number of power dams in various parts of the state were also the subjects of similar rumors. But these reports were either entirely without foundation, as in the case of the Columbus dam, or else the dams were relatively unimportant, so that this article may well be confined to the canal reservoirs.
The Ohio canal system, built in the second quarter of the last century, consists of two main divisions—the Ohio Canal, or eastern route, connecting Lake Erie and the Ohio river by way of the Cuyahoga, Tuscarawas, Muskingum, Licking and Scioto river valleys; and the Miami and Erie Canal, or western route, connecting Lake Erie and the Ohio river by way of the Maumee, Auglaize, and Miami river valleys. In addition, the Muskingum river was slack-watered below Zanesville. Numerous lateral, feeder and tributary canals completed a system which had cost approximately $16,000,000 and which comprised in 1850 over 1,000 miles of canals, more than 300 lift locks and half a dozen reservoirs.
In the case of each of the main canal routes, water was lacking on the summit level during the dry season, and the reservoirs were constructed to supplement the normal flow at such times. The Portage Lakes, just south of Akron, were dammed about 1840, to supply the summit of the eastern route; Loramie and Lewistown Reservoirs about 1850–60, for the western route; and the Licking Reservoir, or Buckeye Lake, about 1832, for the Licking summit. In addition, Grand Reservoir, the largest in the state, was built about 1841, to supply the northern slope of the Miami and Erie Canal.
LOOKING DOWN THE EAST RESERVOIR CREVASSE
In the wreckage are the remains of a saloon and of a concrete bridge.
During the middle of the last century, just prior to the Civil War, these canals were very active, and brought in a gross revenue, during some years, of over $500,000. In 1851 the gross earnings were over $799,000, and the net earnings almost $470,000. But later, the decline came, as it did on all of the old canals. As the canal section and lock dimensions were out-grown by the demands of modern traffic, a gradual abandonment of navigation followed, until now, for many years, there has been no canal freight traffic at all. Some of the branch and feeder canals have been officially abandoned, and either left to deteriorate without attention, or else filled up. Several of the reservoirs were dedicated by the legislature, by several acts passed since 1894, to use as public parks and pleasure resorts, with the provision, however, that they must be maintained for canal purposes.
For the past few years, therefore, the only revenues from the canals have been from the leasing of lands for oil well drilling and from the sale of water or water power to private or municipal water works and industrial plants. An annual appropriation has been made, in addition, to assist in meeting the expense of maintenance. There has, therefore, been no great stimulus to comprehensive and thorough work, and probably a great deal of the maintenance has been of a perfunctory character. The canals and reservoirs are in charge of a Board of Public Works of three members, but neither this nor any other state body or official appears to have had the specific duty of investigating these reservoirs from the sole point of view of public safety.
The Portage Lakes, about six miles south of Akron, were provided with no spillway whatever. The only way water could be discharged from them was through a thirty-six inch pipe. At the beginning of the rain-storm, the level in the reservoirs was within about one foot of the top of the embankment. It was not surprising, therefore, that the lakes filled up, overflowed the low embankment and washed out a crevasse about twenty-five feet deep and nearly 200 feet wide. The water overflowed a considerable area of low farm lands.
At the Lewistown Reservoir, which covers 6,000 acres, about a quarter of a mile of the west embankment was overflowed continuously for a day and a half. Waves dashed over the top of the south bank for several days. Both banks were almost despaired of, and a large force of men, including cottagers and citizens from neighboring towns, worked hard, placing logs and sand bags, to save them. In this they were successful, but a large area south of the reservoir was overflowed.
The Loramie Reservoir of 1,830 acres was already filled to above the spillway level when the rain started, and the water reached a maximum elevation of about four feet above the 200 foot spillway. Two small crevasses about twenty and twenty-five feet wide respectively and five or six feet deep, were washed out at a low portion of the embankment.
The Grand Reservoir is one of the largest artificial bodies of water in the world and covers about 13,400 acres. The water rose to about two feet above the ninety-five foot spillway. The water did not come near overtopping the banks, but heavy waves were driven against and over them, eroding them seriously at some points, and softening and furrowing their backs at others. A large force of volunteers worked with the laborers, filling and placing bags of sand, while a company of state militia patrolled the banks. No breaks occurred at any point, but the situation was critical for two or three days.
REPAIRED BREAK IN LORAMIE RESERVOIR EMBANKMENT.
When the break occurred the water was about four feet over the spillway.
These situations teach a lesson that ought never to need repetition. Reservoir failures did not contribute measurably to the flood damage in Ohio. The trouble was caused by excessive and extensive rains.
But even if the reservoirs did not fail with disastrous results, the margin was a narrow one and the lesson is equally plain. It has long been an engineering principle that an earth embankment must not be overtopped. Twenty-four years ago, the Johnstown disaster, due to insufficient spillway capacity, impressed this upon the whole world. And it is an interesting parallel, that this was caused by an old reservoir originally built by the state for canal purposes, and later abandoned and used for pleasure purposes. Yet in Ohio there were four earth embankment reservoirs, one of which had no spillway and a far from sufficient discharge pipe; two of which filled up so that the banks were overflowed; and one which did not overflow, but which filled up sufficiently so that waves were driven over the embankments. Nor was the rainfall one beyond the range of probability. The March storm probably broke all records for combined intensity, duration and extent. But for small drainage areas such as these (52 to 114 square miles) the rainfall was not unprecedented. At least two storms have occurred in Ohio during the past forty years in which the rainfall in forty-eight hours was greater than that recorded in any forty-eight hours of the late storm, at any station, excepting Piqua, which is below the reservoirs in question. And in at least one storm in the same period, the rainfall for twenty-four hours was within .06 inch of the highest twenty-four hour rainfall of last month.
The faults in these reservoirs, then, were not due to a lack of knowledge as to what to expect, but only to failure to apply knowledge already gained. In this case, of course, state ownership put an extra responsibility on Ohio to see that its property was not a menace to its citizens. But, in any case, the state is the only institution which can see that such structures are provided with the necessary facilities to make them safe. Johnstown ought to have taught the necessity of examining reservoirs and dams, and of enforcing suitable standards of design and construction. Yet if we examine the statute books of Ohio we find no legislative provision of this kind whatever. Nor is there any provision for the study, mapping and gauging of the water resources. This is a necessary preliminary to a full understanding of the possible menace from uncontrolled waste.
With only two or three exceptions, conditions are precisely the same throughout the country. Even in Pennsylvania, which has probably suffered more grievously from dam failures than any other state, there is as yet no public knowledge of the design and condition of all dams, and no authority in any official or body to correct a dangerous condition.
Must we wait for another Johnstown or an Austin to change these things? Or will we learn from what might well have occurred in Ohio, and make a repetition of such disasters impossible? The lesson is plain. Will we profit by it?