HYDROLOGY OF NEW YOUK 



827 



other lock on the canal as to induce the belief that the gates were 

 not properly closed at the time of measurement. At lock No. 69 

 on the same canal, the leakage was 6.37 cubic feet per second 

 from an 8-foot lift. 



Mr Talcotf s report is very able, and presents forcibly all the 

 data at hand at that time. It may be said that the data which 

 he gave fixed the following quantities as fairly covering the 

 various losses to which artificial waterways of the dimensions of 

 the original canals of this State are subject. 1 



1) Loss by filtration, absorption and evaporation, 1.67 cubic 

 feet per second per mile. With retentive soils this could be re- 

 duced to from 1.00 to 1.20 cubic feet per second per mile. Mr Tal- 

 cott fixed on 1.10 cubic feet per second per mile for the Genesee 

 valley canal, which was largely built through heavy soils, but 

 this was subsequently found too small. 



2) Leakage at mechanical structures; for locks of 11 feet lift, 

 8.33 cubic feet per second; for leakage and waste at each waste- 

 weir, 0.50 cubic foot per second; for a wooden-trunk aqueduct, 

 an amount depending on the length of the structure, but as an 

 average, 0.058 of a cubic foot per second for each linear foot of 

 trunk may be taken. 



In response to a resolution of the Canal Commissioners of 

 April 12, 1811. O. W. Childs, then Chief Engineer of the Erie 

 canal, prepared a report on the water supply of the western 

 division with reference to the enlargement then in progress. 2 

 In this paper Mr Childs gives the results of measurements made 

 by himself in 1811 of losses from filtration, absorption, evapora- 

 tion, and leakage on the original Erie canal between Wayneport, 

 in Wayne county, and Pit lock, which corresponded to lock 53. 

 near Clyde, of the present canal. He also gave the result of 

 measurements made by Alfred Barrett between Pittsford and 

 Lockport. 



x The quantities here given apply to canals 40 feet by 28 and 4 feet deep, 

 and with locks 90 feet in length and 15 feet in width and 8 to 10 feet lift. 



a See Supply of Water Required for the Canal Between Lockport and the 

 Seneca River, by O. W. Childs: An. Rept Canal Com. (1848). Ass. Doc. 

 No. 10, p. 141-175. 



