the Legislature's height requirement. The huge stone structure was a major contributor to the enormous jump in the final cost of the Aqueduct to $9.5 million. When Douglass took over as chief engineer of the Croton project in June 1835, his first task was to lead a survey party into West- chester County. Stephen Allen was less than impressed with what he regarded as an unnecessary delay, since Douglass already had made two previous examinations of the Aqueduct's line. Douglass further perturbed Allen by taking a year to furnish maps and then conducting a fourth survey. To do so Douglass asked for a larger 19 staff. Allen vetoed the request because he sought to show progress as well as economy and it seemed to the Water Commissioners that Douglass was interested in neither. Finally, by September 1836, the surveys were complete, but lack of bid specifications resulted in additional delays. Douglass' excuses and continual requests for more staff resulted in the Water Commissioners asking for his resig- nation. Refusing to leave, the Commissioners fired him. Douglass' removal brought to the chief engineer's position the man who supervised construction for nearly 13 years and was most responsible for the successful and timely completion of the "Old Croton," John B. Jervis (figure 11). The selection of Jervis to direct the building of the Croton Aqueduct was due largely to his experi- ence with artificial waterways. Jervis had no formal education as an engineer, but worked his way up through the various jobs on a sur- vey party, beginning with that of axeman. He started in 1817 and by 1825 had "graduated" from the civil engineering "school" of the Erie Canal and immediately thereafter accepted a position as Benjamin Wright's principal assistant on the Delaware and Hudson figure 12: Fayette B. Tower, Croton Aqueduct at Haarlem River (High Bridge), C.1842, ink witli watercolor wash on paper Courtesy Mrs. Helen Tower Wilson. Photo: T. Harnik Canal. Within 2 years fie succeeded Wright as chief engineer. Upon completion of the Delaware and Hudson in 1830, Jervis digressed from canals long enough to build the first two railroads in New York State. Three years later he was back to canals, this time it was the Chenango between Utica and Binghamton, New York. Then in early 1836 Jervis was appointed to head the eastern division of the Erie Canal enlargement project. After only a few months on New York's principal waterway, he was lured to the Croton project by the prospect of engineering one of the nation's first major urban water systems. Jervis eagerly plunged into his new assignment in October 1836, within ten days of his taking the chief engineer's position. He began by examining the site of the proposed Croton Reservoir and the line of the water tunnel from the dam location to the Harlem River, as laid out by Major Douglass. Jervis opted for and approved of Douglass' route along the Hudson River since, as he noted, the line was "side-lying" with land along the line either much above it on one side or much below on the other (figure 13). No great varia- tion would have been possible. Jervis also concurred with the loca- tion of the dam at Garretson's Mill, seven miles upstream from the Croton's junction with the Hudson. He felt that a high dam would create a large reservoir wherein a more complete deposit of sedi- ment would occur. Yet, in his report to the Water Commissioners he expressed caution at placing high dams across rivers that were subject to heavy floods. The Commissioners ignored his concerns however, and a little more than 4 years later a January 1841 flood carried away a major portion of the dam with a loss of three lives. A replacement structure of novel construction and design was rapidly completed under Jervis' direction and remained in use for 64 years until superseded by a larger structure. The Croton Dam, which created a 400-acre lake, was the first big masonry dam in the United States and, because of its design, was in the vanguard of modern hydraulic engineering (figures 2 & 15). But it was only one of the several structures planned for the Croton water system. Another was the nearly 40-mile-long tunnel needed to carry the Croton water from the Dam to the Distributing Reservoir on Murray Hill, between 5th and 6th Avenues, from 40th Street to 42nd Street (figure 16). Douglass proposed that the tun- nel be constructed of stone with the top arched, the bottom an inverted arch, and the side walls tapering slightly inward toward the bottom. The brick- and stone-lined Interior would be 7 feet 5 inches figure 13. above: Method of Construction on Steep Side Hiils [detail], c.1837-39, watercolor and ink on paper Courtesy Jervis Public Library, drawing #199. Photo: