The cities of the second class of this Commonwealth, for the purpose of preventing damage from floods, are authorized to provide for the cleansing, regulation, and control of streams and rivers lying either in whole or in part within their limits, and to construct public works within their respective limits for such purposes; and, if the corporate authorities thereof deem it necessary and for the benefit of any such city, to participate with the United States and this and other States and the several cities, counties, and other municipal and public corporation through which such rivers or streams flow, in constructing such public works in or along such rivers or streams, either within or without the limits of such cities, and either within or without the limits of this Commonwealth, as may be deemed necessary for such purposes, and to enter into contracts therefor; but nothing in this act contained shall be construed to repeal in any way, or in any way alter or abridge, the provisions of the act, approved the twenty-fifth day of June, one thousand nine hundred and thirteen, entitled “An act providing for the regulation of dams, or other structures or obstructions, as defined herein, in, along, across, or projecting into all streams and bodies of water wholly or partly within, or forming part of the boundary of, this Commonwealth; vesting certain powers and duties in the Water Supply Commission of Pennsylvania, for this purpose; and providing penalties for the violation of the provisions hereof.”¹