﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  olo 
  

  

  Temporarily, 
  much 
  greater 
  fluctuations 
  than 
  indicated 
  in 
  the 
  

   foregoing 
  table 
  have 
  been 
  experienced, 
  due 
  largely 
  to 
  wind 
  action, 
  

   to 
  which 
  Lake 
  Erie, 
  on 
  account 
  of 
  its 
  shallowness, 
  and 
  the! 
  fact 
  

   that 
  its 
  general 
  direction 
  is 
  favorable 
  for 
  the 
  sweep 
  of 
  the 
  pre- 
  

   vailing 
  winds, 
  is 
  peculiarly 
  subject. 
  In 
  regard 
  to 
  the 
  measure- 
  

   ments 
  of 
  the 
  Lake 
  Survey, 
  it 
  may 
  be 
  remarked 
  that 
  they 
  indicate 
  

   large 
  variations 
  in 
  discharge 
  from 
  all 
  of 
  the 
  lakes, 
  from 
  the 
  effects 
  

   of 
  winds 
  and 
  other 
  disturbing 
  causes, 
  but 
  give 
  little 
  clew 
  to 
  the 
  

   quantities 
  at 
  either 
  of 
  the 
  extremes 
  of 
  high 
  or 
  low 
  water. 
  Ac- 
  

   cording 
  to 
  Lyman 
  E. 
  Cooley 
  the 
  extreme 
  low-water 
  discharge 
  is 
  

   probably 
  20 
  to 
  30 
  per 
  cent 
  less 
  than 
  the 
  Lake 
  Survey 
  figures, 
  and 
  

   extreme 
  high 
  water 
  20 
  to 
  30 
  per 
  cent 
  more. 
  

  

  Measurements 
  of 
  the 
  amount 
  of 
  water 
  flowing 
  in 
  Niagara 
  river 
  

   were 
  begun 
  in 
  December, 
  1891, 
  at 
  a 
  time 
  when 
  the 
  water 
  in 
  Lake 
  

   Erie 
  was 
  very 
  low 
  and 
  the 
  conditions 
  were 
  considered 
  specially 
  

   favorable 
  for 
  minimum 
  discharge. 
  The 
  results 
  are 
  given 
  in 
  the 
  

   Annual 
  Keport 
  of 
  the 
  Chief 
  of 
  Engineers 
  for 
  1893, 
  part 
  VI, 
  pp. 
  

   4361-1371. 
  The 
  point 
  selected 
  was 
  about 
  1000 
  feet 
  below 
  the 
  Inter- 
  

   national 
  bridge 
  at 
  Black 
  Rock, 
  near 
  the 
  foot 
  of 
  Squaw 
  island, 
  at 
  

   which 
  point 
  the 
  river 
  is 
  free 
  from 
  eddies. 
  Niagara 
  river, 
  on 
  leav- 
  

   ing 
  Lake 
  Erie, 
  has 
  a 
  nearly 
  straight 
  channei 
  about 
  2000 
  feet 
  wide 
  

   for 
  the 
  first 
  2 
  miles. 
  The 
  fall 
  in 
  this 
  section 
  is 
  from 
  1 
  to 
  5 
  feet, 
  

   and 
  the 
  velocity 
  ranges 
  from 
  7 
  miles 
  per 
  hour 
  at 
  the 
  upper 
  end 
  to 
  

   about 
  5 
  miles 
  at 
  the 
  lower 
  end. 
  The 
  point 
  was 
  chosen 
  . 
  after 
  care- 
  

   ful 
  consideration, 
  as 
  the 
  point 
  in 
  that 
  vicinity 
  least 
  subject 
  to 
  

   disturbance. 
  In 
  taking 
  the 
  cross 
  sections, 
  the 
  width, 
  which 
  varies 
  

   slightly 
  with 
  different 
  stages 
  of 
  the 
  river, 
  was 
  accurately 
  deter- 
  

   mined 
  for 
  gage 
  readings 
  1 
  foot 
  apart, 
  and 
  for 
  extreme 
  points 
  the 
  

   width 
  was 
  determined 
  by 
  interpolating 
  values 
  derived 
  from 
  the 
  

   known 
  slope 
  of 
  the 
  river 
  banks. 
  A 
  local 
  gage 
  was 
  established 
  at 
  

   the 
  draw 
  pier 
  of 
  the 
  International 
  bridge, 
  by 
  setting 
  gage 
  boards 
  on 
  

   each 
  side 
  of 
  the 
  pier, 
  with 
  the 
  zeros 
  of 
  the 
  gages 
  on 
  the 
  same 
  level. 
  

   The 
  local 
  gage 
  was 
  read 
  at 
  the 
  beginning 
  and 
  close 
  of 
  all 
  velocity 
  

   observations, 
  and 
  the 
  gage 
  at 
  Buffalo 
  Avas 
  read 
  at 
  7 
  a. 
  m. 
  and 
  1 
  

   and 
  7 
  p. 
  m. 
  The 
  zero 
  of 
  this 
  latter 
  gage 
  is 
  at 
  the 
  mean 
  level 
  of 
  

   Lake 
  Erie, 
  or 
  572.23 
  feet 
  above 
  mean 
  tide 
  at 
  New 
  York 
  in 
  the 
  

   Erie 
  canal 
  levels, 
  or 
  as 
  used 
  by 
  the 
  government 
  engineers, 
  572.96 
  

   feet. 
  During 
  the 
  velocity 
  observations 
  in 
  December, 
  1891, 
  Lake 
  

   Erie 
  was 
  about 
  1.5 
  feet 
  below 
  its 
  mean 
  level, 
  and 
  is 
  stated 
  not 
  

  

  