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THE RELATION OF THE FLOOD CONTROL WORKS OF THE MIAMI CONSERVANCY DISTRICT TO POWER DEVELOPMENT Author(syf & K D V + 3 D X l Source: Journal (American Water Works Associationyf , Vol. 10, No. 3 (MAY, 1923yf S S - 438 Published by: American Water Works Association Stable URL: http://www.jstor.org/stable/41224996 Accessed: 18-06-2017 21:16 UTC JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://about.jstor.org/terms American Water Works Association is collaborating with JSTOR to digitize, preserve and extend access to Journal (American Water Works Associationyf This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms THE RELATION OF THE FLOOD CONTROL WORKS OF THE MIAMI CONSERVANCY DISTRICT TO POWER DEVELOPMENT1 By Chas. H. Paul2 The flood of March, 1913, was the greatest ever recorded in the Miami Valley, Ohio. Large sections of the business and residential district of Dayton and Hamilton were inundated to depths of 10 to 12 feet. At Dayton, the levees guarding the down-town district were overtopped by 6 feet or more, and the peak flow through the city exceeded the capacity of the river channel by nearly 300 per cent. Similar conditions existed in the other cities and towns in the valley. The property loss was estimated at $100,000,000. Immediately following the flood, relief committees were organized in the different cities, and plans for prevention of future floods be- gan to be formulated. Each community worked independently at first, with the idea that each would work out its own salvation, the first thought in the mind of every one being that the desired results could be accomplished by channel enlargement. Soon after systematic engineering study was begun, however, two things became apparent; first, that channel enlargement alone, to the extent re- quired, was not practicable; second -, that one city by itself could not adequately protect itself, and that it was a job for the whole valley to undertake as a unit. A combination of channel enlargement and retarding basins was the final solution of the problem. But there was no practical way, under the Ohio laws then exist- ing, for the valley to organize as a unit and carry through a project such as this. It became necessary, therefore, to enact legislation to permit and protect such an organization. The Conservancy Act of Ohio, passed in 1914, paved the way for the organization of the Miami Conservancy District, which was effected soon thereafter. A map of the Miami Valley (fig. 1yf V K R Z V W K U H H P D L Q E U D Q F K H V R f the river coming together at the City of Dayton. From west to 1 Presented before the Central States Section meeting, November 2, 1922. 2 Chief Engineer, Miami Conservancy District, Dayton, Ohio. 431 This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms 432 CHAS. H. PAUL Fig. 1 This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms FLOOD CONTROL WORKS OF MIAMI DISTRICT 433 east they are the Stillwater, Miami and Mad Rivers, flowing on south under the name of the Miami. Wolf Creek joins the Miami also at Dayton just below the junction of the three main tributaries. Lor- amie Creek flows into the Miami branch at the upper end of the valley, just above Piqua. Twin Creek joins the main river between Frank- lin and Middletown. Four Mile Creek comes in just above Hamil- ton. The drainage area above Hamilton is 3600 square miles. Above Dayton it is 2600 square miles. As finally adopted, the Miami Conservancy plan provides for channel enlargement through all the cities and towns affected by floods, to the extent that is economically feasible, supplemented by retarding basins which will hold back the crest of the flood, by re- stricting the flow through the dams and backing up the surplus tem- porarily in the basins. The outlets through the dams are not con- trolled by gates, but are designed of such size that their combined discharge, under maximum head (full basinyf Z L O O Q R W R Y H U W D [ W K e capacity of the improved river channels through the cities below. The maximum flood provided for is 40 per cent greater than the 1913 flood. After an exhaustive study of rainfall and runoff records, topographic conditions, and other pertinent factors, it is believed that this maximum is in excess of any flood that may occur in this locaUty. Referring again to figure 1, channel enlargement is pro- vided at Piqua, Troy, Dayton, West Carrollton, Miamisburg, Franklin, Middletown and Hamilton. Dams, forming retarding basins, are located at Lockington on Loramie Creek, at Englewood on Stillwater River, at Taylorsville on the Miami, at Huffman on Mad River, and at Germantown on Twin Creek. The cost of the work is met by special assessment against the property benefited. It was necessary to relocate 50 miles of railroad lines throughout the valley, in order to get them out of the way of the dams and re- tarding basins. These included the Big Four and Erie between Dayton and Enon, the Ohio Electric between Dayton and Medway, the Baltimore and Ohio between Dayton and Tippecanoe City. New locations satisfactory to the railroad companies were made at the expense of the District, under the general directions of the rail- road companies. It was necessary in every case to complete the new lines, ready for traffic, before the old lines could be abandoned. The old lines then became the property of the District, the rail and ties being salvaged for what they would bring. This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms 434 CHAS. H. PAUL Channel improvement, to a greater or less extent, is almost cer- tain to be an economical feature of a flood control project. Even when full protection may not be secured by such means, there is usually much to be gained, at moderate expense, by removing bars and islands, and by deepening, widening, or straightening channels within reasonable limits. The cost of additional capacity increases relatively, until finally an economical limit is reached. In the Miami Conservancy project the retarding basin control has permitted chan- nel enlargement to be confined to moderate limits through most of the cities except Hamilton, where a considerable widening of the channel, which had been severely encroached upon by the industrial plants, was unavoidable. This work at Hamilton involved con- siderable property damage. Three general methods of channel improvement were required. First, that in which channel excavation is the essential or most prominent feature, as at Hamilton and Dayton; second, that in which the work is confined almost entirely to levee construction, as at West Carrollton, Miamisburg, Franklin, and Middletown; and third, a combination of these two features, as at Troy and Piqua. Cut-off channels helped the situation, also, at Troy and at Middle- town. Clearing out trees and other obstructions was worth while in several places. The standard section of improved channel at Dayton and Hamil- ton has a low water channel about 150 feet wide with flat slopes, or beaches, on either side, extending out to the toes of the levees. The low water channel is located in the center of the river, where the latter is straight, and near the outside of the bends where the chan- nel is curved. Having determined upon the channel capacity ob- tainable at reasonable expense, the object then is to design a standard channel section which will give velocities of flow as nearly uniform as possible at any given stage, and one that will be reasonably self- maintaining. To meet these requirements it has been necessary in some cases to actually narrow up the old channel at certain points in order to prevent a decrease of velocity at such points, which would result in the formation of bars. Channel improvement in most of these cases resulted in increased velocities of flow. To prevent erosion of banks where good sod is not sufficient, concrete revetment is used at critical points. One of the big engineering problems in connection with this proj- ect was the determination of number and size of retarding basins, This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms FLOOD CONTROL WORKS OF MIAMI DISTRICT 435 and the balancing of retarding basin capacities, outlet capacities through the dams, and improved river channel capacities through the cities. There is no time here to go into the details of this problem, which, however, has been discussed at length in one of the Technical Reports published by the District.3 As has been said already, the final layout of the project included the construction of five dams at the locations indicated heretofore. The principal dimensions of the five dams are as follows: GERMAN- ENGLE- LOCK- TAYLORS- TOWN WOOD INGTON VILLE плм DA DAM DAM • DAM DAM плм DA Maximum height, feet Length, feet Volume eathwork, cu. yd Volume concrete work, cu. yd.... 17,400 26,500 32,000 48,000 37,500 Maximum storage capacity to spillway crest, acre feet Each of the five dams was built by the hydraulic fill method, with concrete outlet structures designed of such size as to give the required control of floods. Each dam is also provided with a con- crete spillway. It is apparent that gate control of the outlets would allow a more precise control of floods, but in the Miami Valley large floods occur only at long intervals. They might be fifty or one hun- dred years apart. Under those circumstances it was thought un- wise to depend upon gate operation. The gates might not be in operating condition when needed, through lack of use, or neglect; or the operators might fail to act intelligently at the critical time; either of which contingency might bring disastrous results. Gate control, required only once or twice in a lifetime, is not dependable. Automatic control, while not quite as economical, is much safer in such cases. The operation of the project is simple. The ordinary flow of the river passes through the dams and on down the channel unimpeded. Small floods pass on with very little interference. Floods of moder- ate size are retarded somewhat by the dams but only for short periods. The large floods find themselves throttled down by the dam outlets to the extent that only a portion of the flow may pass. Just as your 8 Technical Reports, Volume VIT - Hydraulics of the Miami Flood Control Project. This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms 436 CHAS. H. PAUL wash basin, with the faucets turned on, may be filled, even with the drain plug removed, so the retarding basins, during heavy storms, become temporary reservoirs, holding back the peak of the flood, while so much of the flow as the outlets will handle passes through the dams and on down the river without overtaxing the capacities of the improved channels. As the storm subsides the basins im- mediately begin to empty themselves, just as the wash basin will become empty as soon as the flow through the faucets iff sufficiently decreased. With a storm like that of 1913, all of the retarding basins, with one exception, would be empty, ready for another flood within seven days after the rain had ceased. The schedule of work, as laid down at the start of the construction period, called for the completion of the last dam in June, 1923. In spite of war conditions, labor shortage, difficulties of obtaining materials, car shortage, etc., all five of the dams were near enough to completion to be ready to function in the fall of 1921, and all con- struction work will be finished by the end of the working season of 1922, - a full year ahead of schedule. While the project has not yet been called upon to handle a maxi- mum flood, the spring rains of 1922 furnished a test which gave the public its first demonstration of the efficiency of the work. On Thursday night and Friday, April 13 and 14, a heavy rainfall oc- curred which was general over the whole Miami drainage area. At Dayton it measured 3.11 inches, nearly all of which fell within a twenty-four period. This followed frequent rains during the five or six days just preceding, so that it fell on saturated ground, and caused a peak runoff somewhat in excess of any that had occurred since the organization of the Miami Conservancy District and the beginning of flood control work in the Valley. With the channel improvement work nearing completion through the cities, and the dams in operation, this gave the system its first opportunity to function. Under old conditions without the flood control works, the water would have reached the old danger mark at Dayton, and would have been the cause of considerable alarm at several points along the river, particularly at Dayton, Middletown, and Hamilton. In fact there would have been a flood scare, for a few hours more of rain, under old conditions, would have been serious. As it was, the flood control works of the District were just beginning to show their value, and there was an immense capacity still avail- able within the river channels and in the retarding basins. This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms FLOOD CONTROL WORKS OF MIAMI DISTRICT 43? The maximum depth of water stored in each of the retarding basins was as follows: feet Germantown Englewood Lockington Taylorsville Huffman A total of approximately 36,000 acre feet of water was held back. While this was insignificant compared with the total capacity of the basins, it was enough to make a good showing, and at Englewood and Germantown particularly it was viewed with great interest by- many thousands of people. At both these places excellent examples were given of the actual working of retarding basin control. During the early stages of the flood the water passed on through the outlets unimpeded. As the flood increased the limit of free flow through the outlets was reached and water slowly backed up in the basins. This first occurred at Germantown and Englewood, where the outlets are smaller than at the other dams, compared with the size of the streams. As the water backed up in the basins the discharge through the outlets increased slowly, and the action of the hydraulic jump came into notice as it cut down the high velocity of the water within the limits of the stilling pool. At both Germantown and Englewood velocities as high as 25 to 30 feet per second were reduced, by means of the hydraulic jump, to 5 or 6 feet per second. Everything worked out at the dams exactly as was expected. The things which made the most impression on the general public were, the visual evidence of actual storage back of the dams; the immense amount of storage capacity still available in the basins; the marked effect of the hydraulic jump, or stilling pool, reducing the high veloci- ties at the conduit outlets, and the comparatively low stage of the rivers through the cities. While it was apparent that this flood was small compared with the maximum that the project was designed to handle, it was still a clear demonstration of the effectiveness of the works, and the people of the Miami Valley then realized that flood danger, for them, was a thing of the past. From this brief description of the Miami flood control project it will be seen that it has no effect whatever on water supply or power development. The design of the works is such that no combination This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms 438 CHAS. H. PAUL with water supply or power projects is feasible. No permanent storage is provided at any of the retarding basins, their full capacity being held available for flood control. As far as a combination with power development is concerned, there are several reasons why that is not feasible. First, the low water flow of the Miami River is small, and long period storage to augment the flow during the low water reason is not practicable in combination with the retarding basins. Flood control requirements demand that the basins remain empty except when called upon to hold back surplus flood waters. There is not room in the basins for flood control capacity on top of storage for power purposes. Second, fall could be provided only by backing up the water at the dams and that, again, would reduce the available flood control capacity. Third, the lands within the basins are now available for farming and are so used, it having been necessary only to relocate the buildings on high ground. Some of the best crops in the valley are raised within the limits of the retarding basins. The big floods, when they do occur, almost always come in the spring, before the crop season, and instead of damaging the crops, they leave a deposit of silt which is valuable as a fertilizer. Such lands are too valuable to be flooded for the sake of the small amount of water power that might be obtained thereby. As for water supply, the cities in the valley aré otherwise provided for, and as yet there has been no reason to consider water supply storage in this connection. Had such a demand arisen, the same objections would have applied as have been mentioned. There is a further objection to any combination of this sort. Water supply or power storage, once established is required constantly. The de- mand is continuous and evident, and increases as the communities grow. Flood control requirements are much less evident to the general public, especially in a locality where maximum floods may occur only once or twice in a lifetime. There is grave danger in such cases that, in a combination scheme, the flood control require- ments would be sacrificed to the more insistent demands of the other, with the result that eventually the original flood protection might be seriously reduced. One of the big problems in the Miami Valley today is to keep alive in the public mind the necessity of maintaining the flood control works at 100 per cent efficiency, ready for the su- preme test when it comes. That test may not come for a century, it may come tomorrow, it surely will come some day. When it does come, the value of complete protection, with original capacities unimpaired, will be fully realized. This content downloaded from 131.238.108.185 on Sun, 18 Jun 2017 21:16:05 UTC All use subject to http://about.jstor.org/terms