﻿488 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  The 
  minimum 
  cross-section 
  allowed 
  through, 
  the 
  bridges 
  is 
  

   10,500 
  square, 
  feet. 
  The 
  dykes 
  have 
  a 
  total 
  length 
  of 
  4.9 
  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 
  67 
  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 
  to 
  a 
  free 
  discharge 
  of 
  floods. 
  The 
  river 
  

  

  