THEcomplete failure of the Austin dam, with its resultant loss of property and human life, has naturally drawn attention to the early history of this structure. The dam was constructed in the year 1909, to replace a smaller dam higher up stream built about eleven years previously, for the purpose of impounding the water required for a pulp mill. The width of the valley at the point where the new dam was placed is 350 feet, and the reservoir was designed to impound 200,000,000 gallons of water, with the spillway 42 feet above the level of the valley. The width of the dam at the top was 2 feet 5 inches, at the bottom 30 feet. The length of its upper face was 544 feet. The rock foundation of the valley consists of horizontal layers of sandstone with shale sandwiched in between. The building of the dam, which contained about 16,000 cubic yards of concrete, was begun in May and completed about December 1st, 1909. In preparing the foundations, about 8,000 cubic yards were excavated, and an earth embankment was laid against the upstream face of the dam at a slope of 3 : 1, reaching within 27 feet of the normal water level. The concrete structure was reinforced with twisted steel rods 11/4 inches in diameter and 25 feet long, placed 2.7 feet apart. On either side of the spillway a pilaster was built, which also was reinforced with half-inch steel rods, as was the top of the dam. Very significant is the fact that, upon completion of the dam, there was found to be a crack extending from the top to the ground level, and in December, 1909, a second crack appeared. About January 17th, 1910, the weather was warm, and abundant rain fell. On the 21st of January, the dam was overflowing. On Sunday, the 22nd, water was found to be leaking from A Call for State Legislative Control the toe of the dam. It was suggested at the time that the failure of the dam to withstand the flood of 1910 was due to two causes. First, the great bulk of the hurriedly built concrete, some of which was laid in freezing weather, and completed only six weeks before the time when the maximum pressure occurred; secondly, the seepage of water through the rock strata under the dam. As far as we can learn, the work done upon the dam at this time in the way of investigation of conditions and of provision against further damage, was altogether inadequate, particularly in view of the fact that heavy seepage had taken place through the porous material below the foundation. The least that could have been done would have been to sink a curtain wall through the underlying rock, etc., carrying it down everywhere to a thoroughly impervious stratum. Failing this, the dam should have been abandoned altogether. In the construction of storage dams, of whatever character, it is an axiom that there should be no suspicion whatever as to the impermeability, not merely of the dam itself, but of the natural formation upon which it is laid. There is no mystery about the construction of watertight dams. The problems connected with their foundations and with the stresses in the dams themselves are perfectly well understood among competent engineers, and have been so understood for a long period of time. We know of no engineering-work regarding which the possibilities of failure are so inany, and their results so serious, as that which has to deal with the impounding of vast quantities of water by the erection of artificial barriers. Thanks to accumulated stores of knowledge, and to the very thorough training, theoretical and practical, to which the competent civil engineer is subjected, both at the engineering schools and colleges and in his subsequent career, there is abundance of high class professional skill available for those individuals or corporations who wish to undertake the construction of works of this character. One of the most important lessons of this disaster is that which teaches the necessity for the employment of engineers skilled in this particular branch of work. Another lesson is that when the engineer has been engaged, he should be left an absolutely free hand In determining the character of the construction that should be employed. To engage an engineer to design a dam of importance and then impose a limit of cost is to tempt him to play fast and loose with the ethics of his profession, aiid imperil the safety of the proposed structure. The photographs of the wrecked dam and the devastation which was caused by the flood of water that swept through the valley below tell their own story so clearly that but little comment is necessary. If we bear in mind that seepage was occurring below the foundation, the probable sequence of events, as the dam gave way, is easy to understand. We spoke early in the present article of certain cracks that appeared when the dam was first filled with water. Very significant is the fact that one of the largest breaks in the dam wall occurred along the very lines of these old fractures. Settlement due to gradual washing out of the underlying porous material, coupled with changes of temperature, may have induced the original cracks. Further washing out below the foundations would cause these cracks to become complete lines of cleavage. Then it was that the loss of transverse (Continued on page 336.) 289999? SCIENTIFIC AMERICAN Founded 1845 NEW YORK, SATURDAY, OCTOBER 14, 1911 Published by Munn& Co., Incorporated. Charies Allen Munn. President; 1 rederick Converse Beach, Secretary and Treasurer; all at 3til Broadway. New York Entered at the Post Office of New York. N. Y.. as Second Class Matter Copyright 1911 by Munn Co., Inc. Subscription Rates Subscription one year......................... $3.00 Postage prepaid in United States and possessions, Mexico, Cuba, and Panama Subscriptions for Foreign Countries, one year, postage prepaid, 4.50 Subscriptions for Canada, one year, postage prepaid,...... 8.75 The Scientific American Publications Scientific American (established 1845).........per year, $3.00 Scientific American Supplement (established 1876). ; 5.00 American Homes and Gardens.............. ; 3.00 The combined subscription rates and rates to foreign countries, including Canada, will be furnished upon application. Remit by postal or express money order, bank draft or check, Munn&Co., Inc., 361 Broadway, New York The Editor is always glad to receive for examination illustrated articles on subjects of timely interest. If the photographs are sitarp, the articles ."JlOrt, and the facts authentic. the contributions will receive special attention. Accepted articles will be paid for at regular space The purpose of this journal is to record accurately, simply, and interestingly, the world's progress in scientific knowledge and industrial achievement.
This article was originally published with the title "The Failure of the Austin Dam" in Scientific American 105, 16, 331-332 (October 1911)