﻿HYDROLOGY 
  OP 
  NEW 
  YORK 
  489 
  

  

  channel 
  is 
  characterized 
  by 
  breadth 
  and 
  shallowness, 
  with 
  abrupt 
  

   changes 
  of 
  width 
  and 
  depth. 
  This 
  condition 
  has 
  been 
  brought 
  

   about 
  by 
  the 
  fact 
  that 
  the 
  river 
  approaches 
  Elmira 
  with 
  a 
  high 
  

   velocity, 
  due 
  to 
  rapid 
  descent 
  for 
  some 
  miles 
  above. 
  It 
  therefore 
  

   reaches 
  the 
  city 
  loaded 
  with 
  sediment 
  and 
  moving 
  large 
  amounts 
  

   of 
  detritus 
  along 
  its 
  bed, 
  but 
  on 
  reaching 
  the 
  flatter 
  grades 
  the 
  

   velocity 
  is 
  checked 
  and 
  the 
  stream 
  is 
  no 
  longer 
  able 
  to 
  move 
  this 
  

   material, 
  which 
  is 
  left 
  in 
  the 
  channel, 
  gradually 
  accumulating 
  

   with 
  each 
  successive 
  flood. 
  The 
  shoaling 
  of 
  the 
  channel, 
  due 
  to 
  

   such 
  accumulation 
  of 
  material, 
  encourages 
  the 
  erosion 
  of 
  banks, 
  

   with 
  the 
  result 
  that 
  the 
  channel 
  increases 
  in 
  width 
  and 
  becomes 
  

   shallower. 
  During 
  the 
  flood 
  of 
  1889 
  the 
  river 
  rose 
  to 
  a 
  hight 
  of 
  

   14 
  feet 
  above 
  low 
  water 
  mark, 
  and 
  a 
  number 
  of 
  floods 
  since 
  that 
  

   time 
  have 
  approached 
  this 
  in 
  severity. 
  In 
  March, 
  1902, 
  about 
  

   thirteen 
  hundred 
  acres 
  within 
  the 
  business 
  and 
  residence 
  portions 
  

   of 
  the 
  city 
  were 
  inundated 
  and 
  the 
  flood 
  damage 
  in 
  that 
  year 
  has 
  

   been 
  estimated 
  at 
  $155,000. 
  

  

  Mr 
  Collingwood 
  prepared 
  five 
  alternative 
  plans 
  for 
  flood 
  pre- 
  

   vention, 
  differing 
  in 
  the 
  extent 
  of 
  protection 
  to 
  be 
  secured 
  and 
  

   the 
  permanence 
  and 
  character 
  of 
  the 
  improvement. 
  The 
  first 
  of 
  

   these 
  is 
  estimated 
  to 
  cost 
  $700,000; 
  the 
  second, 
  $640,000; 
  the 
  

   third, 
  $376,000; 
  the 
  fourth, 
  $336,000, 
  while 
  in 
  the 
  fifth 
  scheme 
  

   an 
  immediate 
  expenditure 
  of 
  $133,000 
  is 
  suggested, 
  with 
  moder- 
  

   ate 
  annual 
  expenditure 
  until 
  the 
  desired 
  result 
  is 
  finally 
  reached. 
  

  

  In 
  this 
  connection, 
  Mr 
  Collingwood 
  suggests 
  that 
  the 
  city 
  

   should 
  buy 
  its 
  own 
  dredging 
  plant. 
  The 
  total 
  cost 
  of 
  a 
  suitable 
  

   plant 
  would 
  be 
  about 
  $25,000. 
  In 
  order 
  to 
  prevent 
  the 
  gradual 
  

   filling 
  up 
  of 
  streams, 
  raising 
  them 
  more 
  and 
  more 
  with 
  each 
  

   flood, 
  Mr 
  Collingwood 
  suggests 
  that 
  the 
  material 
  should 
  be 
  taken 
  

   from 
  the 
  bed 
  of 
  the 
  streams. 
  

  

  Without 
  knowing 
  the 
  condition 
  fully, 
  the 
  writer 
  doubts 
  

   whether 
  any 
  scheme 
  of 
  partial 
  dyking 
  on 
  Chemung 
  river 
  can 
  be 
  

   permanently 
  effective. 
  The 
  whole 
  river 
  should 
  be 
  considered 
  be- 
  

   fore 
  any 
  actual 
  work 
  of 
  construction 
  is 
  undertaken. 
  1 
  

  

  J 
  The 
  facts 
  in 
  regard 
  to 
  floods 
  at 
  Elmira 
  have 
  been 
  obtained 
  from 
  the 
  

   Report 
  on 
  the 
  Protection 
  of 
  the 
  City 
  of 
  Elmira, 
  N. 
  Y., 
  against 
  Floods, 
  by 
  

   Francis 
  Collingwood, 
  dated 
  February 
  12, 
  1890. 
  The 
  balance 
  of 
  the 
  infor- 
  

   mation 
  in 
  regard 
  to 
  floods 
  on 
  Chemung 
  river 
  is 
  from 
  the 
  Report 
  of 
  the 
  

   Water 
  Storage 
  Commission. 
  

  

  