﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  

  

  299 
  

  

  These 
  precipitation 
  data 
  are 
  of 
  special 
  interest 
  because 
  the 
  year 
  

   1895 
  was 
  the 
  culmination 
  of 
  a 
  period 
  of 
  exceedingly 
  low 
  water. 
  

   They 
  show 
  that 
  for 
  a 
  period 
  of 
  four 
  years 
  the 
  precipitation 
  of 
  

   this 
  basin 
  was 
  low, 
  and 
  in 
  consequence 
  the 
  runoff 
  of 
  the 
  tributary 
  

   streams 
  must 
  haYe 
  been 
  exceedingly 
  small. 
  As 
  illustrating 
  this 
  

   proposition, 
  we 
  will 
  refer 
  to 
  the 
  runoff 
  of 
  the 
  Upper 
  Mississippi, 
  1 
  

   where 
  there 
  is 
  a 
  reservoir 
  system 
  controlling 
  a 
  catchment 
  area 
  

   of 
  3265 
  square 
  miles, 
  first 
  operated 
  about; 
  1885. 
  The 
  rainfall 
  

   of 
  the 
  area 
  tributary 
  to 
  these 
  reservoirs, 
  as 
  indicated 
  by 
  records 
  

   kept 
  at 
  Leech 
  lake, 
  Lake. 
  Winibigoshish, 
  and 
  Pokegama 
  Falls 
  

   from 
  1885 
  until 
  the 
  present 
  time 
  is, 
  on 
  an 
  average, 
  from 
  24 
  to 
  

   26 
  inches 
  per 
  year. 
  The 
  highest 
  recorded 
  yearly 
  precipitation 
  

   is 
  31.87 
  incheiS, 
  at 
  Pokegama 
  Falls 
  in 
  1894. 
  The 
  rainfall 
  of 
  the 
  

   area 
  tributary 
  to 
  the 
  Upper 
  Mississippi 
  reservoirs 
  is 
  found 
  to 
  

   be 
  quite 
  similar 
  to 
  that 
  of 
  the 
  region 
  tributary 
  to 
  Lake 
  Superior. 
  

   Hence 
  the 
  runoff 
  of 
  this 
  reservoir 
  system 
  may 
  be 
  considered 
  

   as 
  representing 
  the 
  runoff 
  of 
  the 
  catchment 
  area 
  of 
  Lake 
  

   Superior 
  and 
  the 
  northern 
  portion 
  of 
  Lakes 
  Michigan 
  and 
  Huron. 
  

   The 
  following 
  gives 
  the 
  discharge 
  from 
  these 
  reservoirs 
  for 
  the 
  

   years 
  1892 
  to 
  1895, 
  inclusive, 
  corresponding 
  with 
  the 
  years 
  of 
  

   precipitation 
  shown 
  in 
  table 
  No. 
  39. 
  

  

  AVater 
  year. 
  

  

  1892 
  

  

  1893 
  

  

  1894 
  

  

  1895 
  

  

  Total 
  

  

  Mean 
  

  

  Annual 
  report 
  of 
  Chief 
  of 
  Engineers 
  U. 
  S. 
  Army 
  for 
  1896, 
  part 
  III, 
  

   p. 
  1843 
  ; 
  also 
  for 
  1897, 
  part 
  III, 
  p. 
  2169. 
  

  

  Mean 
  rain- 
  

   fall 
  on 
  

   catchment 
  

   area. 
  

   Inches 
  

  

  Runoff 
  

  

  of 
  

  

  catchment 
  

  

  area. 
  

  

  Inches 
  

  

  Proportion 
  

  

  of 
  runoff 
  

  

  to 
  

  

  rainfall. 
  

  

  Per 
  cent 
  

  

  21.33 
  

  

  4.43 
  

  

  20.8 
  

  

  25.42 
  

  

  3.61 
  

  

  14.2 
  

  

  26.63 
  

  

  3.62 
  

  

  13.6 
  

  

  25.11 
  

  

  2.79 
  

  

  11.1 
  

  

  98.49 
  

  

  14.45 
  

  

  

  24.62 
  

  

  3.61 
  

  

  14.7 
  

  

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