﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  89 
  

  

  The 
  Great 
  Lakes 
  region, 
  with 
  an 
  average 
  elevation 
  of 
  494 
  feet, 
  

   has 
  an 
  average 
  annual 
  precipitation 
  of 
  35.17 
  inches, 
  while 
  the 
  

   Central 
  Lakes 
  region, 
  with 
  an 
  average 
  elevation 
  of 
  690 
  feet, 
  has 
  an 
  

   average 
  annual 
  precipitation 
  of 
  43.41 
  inches. 
  

  

  Mr 
  Turner's 
  table 
  is 
  based 
  on 
  a 
  calendar 
  year, 
  from 
  January 
  to 
  

   December, 
  inclusive. 
  Further 
  data 
  may 
  be 
  obtained 
  from 
  this 
  

   excellent 
  table. 
  

  

  In 
  table 
  No. 
  24 
  of 
  the 
  Upper 
  Hudson 
  Storage 
  Surveys 
  Keport 
  for 
  

   1896 
  there 
  is 
  given 
  the 
  mean 
  precipitation 
  of 
  the 
  Upper 
  Hudson 
  

   catchment 
  area. 
  The 
  stations 
  therein 
  included 
  are 
  : 
  Albany, 
  1825- 
  

   1895, 
  71 
  years; 
  Glens 
  Falls, 
  1879-1895, 
  17 
  years; 
  Keene 
  Valley, 
  

   1879-1895, 
  17 
  years; 
  western 
  Massachusetts, 
  1887-1895, 
  9 
  years; 
  

   northern 
  plateau, 
  1889-1895, 
  6J 
  years; 
  Lowville 
  Academy, 
  1827- 
  

  

  1848, 
  22 
  years; 
  Johnstown 
  Academy, 
  1828-1845, 
  18 
  years; 
  Cam- 
  

   bridge 
  Academy, 
  1827-1839, 
  13 
  years; 
  Fairfield 
  Academy, 
  1828- 
  

  

  1849, 
  22 
  years; 
  Granville 
  Academy, 
  1835-1849, 
  15 
  years. 
  Assum- 
  

   ing 
  the 
  northern 
  plateau 
  as 
  a 
  unit, 
  the 
  total 
  number 
  of 
  years 
  is 
  

   199 
  J, 
  and 
  the 
  mean 
  of 
  all 
  is 
  37.4 
  inches. 
  A 
  reference 
  to 
  the 
  rain- 
  

   fall 
  map 
  in 
  the 
  report 
  of 
  the 
  L^nited 
  States 
  Board 
  of 
  Engineers 
  on 
  

   Deep 
  Waterways 
  will 
  show 
  that 
  this 
  is 
  necessarily 
  an 
  approxima- 
  

   tion, 
  because 
  of 
  great 
  lack 
  of 
  stations 
  in 
  the 
  interior 
  of 
  this 
  

   region. 
  

  

  As 
  regards 
  the 
  catchment 
  area 
  of 
  the 
  Upper 
  Genesee 
  river, 
  

   there 
  is 
  a 
  very 
  decided 
  increase 
  in 
  rainfall 
  as 
  one 
  goes 
  toward 
  

   the 
  source. 
  For 
  the 
  years 
  1889-1896, 
  inclusive, 
  the 
  rainfall 
  in 
  

   the 
  upper 
  area 
  of 
  this 
  stream 
  was 
  42.19 
  inches, 
  while 
  at 
  Rochester 
  

   for 
  the 
  same 
  years 
  it 
  was 
  35.64 
  inches. 
  This 
  statement 
  is 
  

   specially 
  interesting, 
  because 
  there 
  seems 
  to 
  be 
  a 
  well-marked 
  

   line 
  dividing 
  the 
  smaller 
  rainfalls 
  of 
  the 
  lower 
  area 
  from 
  the 
  

   higher 
  rainfalls 
  of 
  the 
  upper. 
  At 
  Hemlock 
  lake, 
  Avon, 
  and 
  Mount 
  

   Morris 
  the 
  rainfalls 
  are 
  all 
  low, 
  the 
  average 
  at 
  Hemlock 
  lake 
  

   from 
  1876-1895, 
  inclusive, 
  being 
  27.56 
  inches. 
  In 
  1880 
  it 
  was 
  21.99 
  

   inches; 
  in 
  1879, 
  22.16 
  inches, 
  and 
  in 
  1881 
  only 
  24.36 
  inches. 
  We 
  

   have 
  here 
  three 
  years 
  of 
  exceedingly 
  low 
  rainfall, 
  in 
  which 
  the 
  

   runoff 
  must 
  have 
  also 
  been 
  very 
  low. 
  In 
  1895 
  the 
  rainfall 
  at 
  

   Hemlock 
  lake 
  was 
  only 
  18.58 
  inches. 
  The 
  average 
  precipitation 
  

   at 
  Avon 
  and 
  Mount 
  Morris 
  from 
  1891 
  to 
  1896, 
  inclusive, 
  was 
  30.12 
  

  

  