In connection with complete contour maps, diagrams, profiles, etc., made from the above work, studies have been made of the cost and effectiveness of a flood wall, in connection with dredging, in deepening, widening and straightening of the river channel at the city, and the cost and effectiveness of regulating the stream flow by storage reservoirs, located throughout the drainage basins. In addition to the collection of a vast amount of general data, including precipitation, taken from the records of the United States Weather Bureau, the work involved many special studies, among which were forest conditions, geology and stream-flow. For the stream-flow studies, gauging stations were established by the Flood Commission and also a number in co-operation with the Water Supply Commission of Pennsylvania. In the forest studies, the co-operation of the United States Forest Service and of the Forestry Department of Pennsylvania were secured. Valuable stream-flow data have been provided by the United States Geological Survey.
At the beginning of the investigations the matter was treated as of local concern only, but as the work progressed the broad aspect of the problem and its national scope were realized, as it became evident that Pittsburgh’s floods had a direct bearing upon the flood troubles of other communities. Further study disclosed the fact that inseparable from the flood problem was the question of navigation, sanitation, water supply and water power, and that the valleys of the Allegheny, Monongahela and Ohio Rivers could be benefited wherever conditions are favorable for the construction of storage reservoirs. On many of the principal tributaries of the Ohio below Pittsburgh, the topography is favorable for storage reservoirs upon a large scale, and floods could be prevented throughout the Ohio valley by extending the plans of the Flood Commission.
An exhaustive report, consisting mostly of original data, has been published by the Commission, as the result of nearly four years of painstaking work. It is said that this report forms the most comprehensive treatment of a subject of this kind that has ever been carried out. The report contains over 900 pages, including numerous maps and diagrams, and a large number of illustrations, showing flood damage, reservoir sites, forest conditions, etc.
FLOOD DAMAGE.
Pittsburgh, which has a population of 533,905, and about twice as much with the contemplated greater city, is located at the head of the Ohio River and at the confluence of the Allegheny and Monongahela Rivers. The combined drainage area, above the city, amounts to 18,920 square miles. Of the two rivers, 150 miles, directly connecting with the city, have been slackwatered. About 14,000 miles of navigable waterway lies below the city. The National Government, in a few years’ time, will have the entire 967 miles of the Ohio River improved.
The tonnage of Pittsburgh, incoming and outgoing, amounted in 1910 to 167,000,000 tons, of which 11,000,000 tons consisted of river traffic. The above total tonnage, which has doubled in the last six years, is twice as great as the combined tonnage of New York, London, Hamburg and Marseilles.
As is frequently the case in communities situated upon the inland rivers of this country, the most important commercial and industrial parts of Pittsburgh are located upon the low lying areas bordering the water. The need of free access to water and of rail and water transportation naturally brings about such development. In fact, on account of the topography, rail communication can in many cases be satisfactorily established only along the stream. Such a condition, however, frequently causes great suffering and interruption to business, involving not only the districts in direct touch with the river, but the whole community.
During the progress of the investigations, it became evident that unless some adequate method of flood relief could be devised and carried out, the larger portion of the flood affected areas could never be properly developed, and the capital invested therein would continue to suffer. The general needs of building operations and of city improvements will of necessity keep pace with the advance of population; and the flood damages, which in their effect involve the home conditions and business life of the entire city and surrounding communities, will become correspondingly greater.
In ascertaining the extent of flood damage to the city, a careful investigation was made of three floods which occurred within a period of about twelve months, from March 15, 1907, to March 20, 1908. In the conduct of this work it was noted that while those coming in direct contact with the floods are alert to the seriousness of the situation during the flood, the matter is, however, after a time almost forgotten; the disposition in most cases apparently being to take the troubles as they come rather than to do anything in the way of even attempting to devise means of relief.
The classification under which this work was done, and the monetary amount of direct losses within the city by the three floods may be given as follows: