1. The Flood Commission is getting data for studying the question of a protective embankment along the river front, and of the proper grades of streets and bridge approaches in the region subject to inundation. The design of such flood-protection works should have important bearing upon the grade, location and design of the permanent bridge abutments. This Commission is also studying the question of impounding the flood waters of the Allegheny and Monongahela Rivers in their upper valleys, which may result in materially lessening the height and velocity of floods in the harbor of Pittsburgh, and consequently, simplify the bridge and navigation problems of the harbor.
2. The question of the best routes for surface cars and rapid transit lines crossing the Allegheny River is now being studied for the City as a part of a comprehensive plan for traction improvements. The result of these studies might readily affect the design of the new bridges.
3. The government experiments recommended by Colonel Alexander of the River and Harbor Committee and authorized in the River and Harbor bill just passed by Congress and providing for the development of a more economical and efficient type of river-boats, requiring less head room than the present antiquated types, may soon show results that would have a decided influence in determining the reasonable clearance heights of bridges.
A typical Paris boat and tows
4. Attention is also invited to the fact that the people of Pittsburgh have voted to expend about $7,000,000 in certain public improvements. Among these are the cutting down of the "Hump," an obstructive hill in the city's midst, widening some streets and filling certain other streets in the North Side and West End that are flooded at high river stages. The material from the "Hump" in the vicinity of the Court House is to be hauled to these North Side streets across the lower Allegheny bridges under question. The work is of great magnitude and it will take at least two years to complete it. Any material alteration to the bridges such as proposed by the Board of Engineers will require a long time to be carried into effect. While this bridge work would be under way, the transportation of the material excavated from the "Hump" and the filling up of the low grade streets of the North Side would have to cease or would be carried on with great difficulty and inconvenience to other traffic. This would tie up the whole work while it is in progress, causing material injury to the city, for it is to be extremely annoying and bothersome while it is in progress, and the longer this period is strung out the worse it will be.
For all of the above reasons we believe that to precipitate the actual reconstruction of the bridges at this time would be most undesirable for the city and prejudicial to the best results, in the long run, for all concerned.
RECOMMENDATIONS
In conclusion we beg to recommend as follows: 1. That the Sixteenth Street and Forty-third Street bridges, which are obstructions to navigation on account of their pier locations, narrow channels, and exceptionally low clearance height, be required to be rebuilt with their piers so located as to give channels conforming to the neighboring bridges, and that their elevation be fixed with regard to eliminating the railroad grade crossings on their approaches, but the minimum clearance shall be fixed in accordance with the closing paragraph below.