﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  449 
  

  

  several 
  feet 
  — 
  variously 
  estimated 
  at 
  from 
  three 
  to 
  five 
  feet 
  — 
  

   higher 
  than 
  the 
  highest 
  known 
  preceding 
  flood, 
  and 
  similar 
  evi- 
  

   dence 
  exists 
  for 
  points 
  on 
  the 
  Genesee 
  up 
  as 
  far 
  as 
  Wellsville. 
  

   This 
  is 
  not 
  true, 
  however, 
  for 
  the 
  lower 
  portion 
  of 
  the 
  valley. 
  

   At 
  Mount 
  Morris 
  the 
  flood 
  hight 
  attained 
  was 
  about 
  that 
  of 
  pre- 
  

   vious 
  floods, 
  but 
  at 
  Rochester 
  the 
  river 
  showed 
  a 
  discharge 
  of 
  

   only 
  about 
  20,000 
  cubic 
  feet 
  per 
  second 
  against 
  36,000 
  to 
  40,000 
  

   or 
  42,000 
  cubic 
  feet 
  per 
  second 
  for 
  the 
  1865 
  flood 
  and 
  the 
  March, 
  

   1902, 
  flood. 
  The 
  excessive 
  precipitation, 
  therefore, 
  must 
  have 
  

   been 
  confined 
  to 
  the 
  headwaters 
  of 
  the 
  river. 
  

  

  It 
  must 
  not 
  be 
  inferred 
  that 
  the 
  maximum 
  flood 
  discharge 
  at 
  

   Portage 
  was 
  less 
  than 
  20,000 
  cubic 
  feet 
  per 
  second, 
  the 
  discharge 
  

   at 
  Rochester. 
  On 
  the 
  contrary, 
  there 
  is 
  good 
  reason 
  to 
  believe 
  

   that 
  the 
  discharge 
  at 
  Portage 
  with 
  only 
  40 
  per 
  cent 
  of 
  the 
  catch- 
  

   ment 
  area 
  was 
  very 
  much 
  in 
  excess 
  of 
  that 
  at 
  Rochester, 
  and 
  the 
  

   reasons 
  for 
  this 
  are: 
  (1) 
  the 
  flood 
  hight 
  at 
  Portage 
  was 
  from 
  

   three 
  to 
  five 
  feet 
  higher 
  than 
  during 
  former 
  extreme 
  floods 
  which 
  

   gave 
  flood 
  discharges 
  of 
  40,000 
  cubic 
  feet 
  per 
  second 
  at 
  Mount 
  

   Morris, 
  which 
  has 
  only 
  7 
  per 
  cent 
  more 
  catchment 
  area; 
  these 
  

   former 
  floods 
  must 
  therefore 
  have 
  discharged 
  not 
  much 
  less 
  than 
  

   40,000 
  cubic 
  feet 
  per 
  second 
  at 
  Portage; 
  five 
  feet, 
  or 
  even 
  three 
  

   feet, 
  added 
  to 
  the 
  crest 
  of 
  these 
  former 
  floods 
  indicate 
  still 
  greater 
  

   discharges 
  and 
  leave 
  little 
  doubt 
  that 
  the 
  discharge 
  at 
  Portage 
  

   was 
  nearly 
  if 
  not 
  fully 
  double 
  that 
  at 
  Rochester; 
  (2) 
  an 
  examina- 
  

   tion 
  of 
  the 
  July 
  flood 
  at 
  Rochester 
  shows 
  that 
  the 
  maximum 
  stage 
  

   of 
  water 
  was 
  reached 
  at 
  Rochester 
  during 
  the 
  afternoon 
  of 
  July 
  

   S, 
  while 
  the 
  maximum 
  stage 
  at 
  Portage 
  occurred 
  during 
  the 
  

   forenoon 
  of 
  July 
  6, 
  indicating 
  that 
  the 
  flood 
  crest 
  occupied 
  

   more 
  than 
  two 
  days 
  in 
  passing 
  from 
  Portage 
  to 
  Rochester. 
  When 
  

   we 
  consider 
  the 
  topography 
  of 
  the 
  valley 
  between 
  Mount 
  Morris 
  

   and 
  Rochester, 
  this 
  time 
  consumed 
  in 
  transit 
  must 
  have 
  been 
  

   accompanied 
  by 
  an 
  elongation 
  of 
  the 
  flood 
  with 
  a 
  corresponding 
  

   diminution 
  of 
  the 
  discharge 
  per 
  second. 
  

  

  A 
  careful 
  study 
  of 
  the 
  circumstances 
  attending 
  this 
  flood 
  of 
  

   July, 
  1902, 
  in 
  conjunction 
  with 
  the 
  other 
  maximum 
  floods 
  in 
  the 
  

   Genesee, 
  leads 
  to 
  the 
  conclusion 
  that 
  the 
  maximum 
  flood 
  at 
  Roch- 
  

   ester 
  has 
  not 
  yet 
  occurred, 
  and 
  that 
  by 
  a 
  combination 
  of 
  circum- 
  

   stances 
  which 
  do 
  not 
  seem 
  at 
  all 
  improbable 
  a 
  maximum 
  flood 
  in 
  

   excess 
  of 
  40,000 
  cubic 
  feet 
  per 
  second 
  may 
  reasonably 
  be 
  expected. 
  

  

  