The failure of this embankment might not only create a devastating flood in the valley below , but also cause a current above , of such irresistible velocity , as would de- stroy the earthen part of the old Croton dam , thus at once cutting off the supply of water to the city until the old dam could be repaired and in addition postponing indefinitely the time when the city could have the addi- tional supply of water which the enlarged reservoir was to furnish . Thus , the writer , was thoroughly convinced that a change in the plan of the structure at this point was nec- essary . Thereupon he recommended to the Aqueduct Commissioners that this entire section of the embank- ment and core wall to the gatehouse be removed and the stone dam extended in its place . But while maintaining that the conditions allowed of no other conclusion , he recommended that a committee of three engineers be ap- pointed to pass upon a question of so vital and wide- spread importance . The Commissioners after personal investigation agreed in this and appointed a committee of expert engineers consisting of Messrs . J. J. R. Croes , Past President of the American Society of Civil Engineers ; Edwin F. Smith , Chief Engineer of the Schuvlkill Navigation Company and Elnathan Sweet , former Engineer of the State of New York . The committee after making an investiga- tion reported unanimously recommending this extension of the stone dam to the gatehouse . The general public will no doubt feel that great weight has been added to these conclusions by the concurrence of the eminent Engineers Prof. William H. Burr , occu- pying the Chair of Engineering of Columbia University , and Mr. Nelson P. Lewis , Chief Engineer of the Board of Estimate and Apportionment of the City of New York ; both of whom had been asked by Mayor Low to investigate and report thereon .