4S8 



NEW YORK STATE MUSEUM 



The minimum cross-section allowed through the bridges is 

 10,500 square feet. The dykes have a total length of 4.0 miles 

 and vary in hight from 4 to 19 feet. These dykes not only extend 

 along the river front opposite the city and for a considerable dis- 

 tance downstream, but also extend for nearly two miles along 

 the westerly bank of Post creek, a torrential tributary reaching 

 the river from the north. Several streams and a number of sur- 

 face-water drains are provided for in different ways — some were 

 carried in closed conduits which extend above high-water mark 

 on the land side; others were carried through the dyke by cast- 

 iron pipes, with gate valves and automatic flap valves at the river 

 end. 



The foregoing river improvement, although inaugurated and 

 carried out as a city measure, did not include a reach of the south 

 bank of the river, which was protected by an embankment and 

 slope wall built a number of years before by the State of New 

 York. In the course of time this embankment has deteriorated so 

 that the portion of the river front protected by it is now in an 

 unsatisfactory condition. During the. floods of 1902 the high 

 water was only kept from going over this old embankment by 

 temporary work. Formerly, the State appropriated funds to 

 maintain this embankment, with the result that the local authori- 

 ties consider that the burden of maintaining it now rests with the 

 State. 



The city of Elmira lies on the Chemung river, about twenty-five 

 miles above where it joins the Susquehanna. Floods are common 

 here the same as at Corning, fifteen miles above. Within the 

 historical period the most severe flood is that of June 1, 1889. At 

 this time, according to a report made by Francis Collingwood, the 

 stream flowed at the rate of 138,000 cubic feet per second (catch- 

 ment, 2,055 square miles), or G7 cubic feet per second per square 

 mile. 



Mr Collingwood submitted a report of his investigations, to- 

 gether with a map of the river with flood profile for June 1, 1889. 

 This profile shows obstructions to flood-flow are caused by a dam 

 extending across the river near the west city line and by several 

 bridges spanning the river below this dam. In addition to these 

 specific obstructions the general condition of the channel through 

 the city is unfavorable <<> ;< free discharge of Hoods. The river 



