﻿

  HYDROLOGY 
  OF 
  NEW 
  YORK 
  421 
  

  

  The 
  following 
  statements 
  in 
  regard 
  to 
  these 
  measurements 
  are 
  

   abstracted 
  from 
  Mr 
  Jervis's 
  report 
  i 
  1 
  From 
  the 
  Eaton 
  brook 
  results 
  

   it 
  appears 
  that 
  the 
  average 
  runoff 
  from 
  June 
  to 
  December, 
  

   inclusive, 
  was 
  39.2 
  per 
  cent 
  of 
  the 
  rainfall 
  and 
  from 
  June 
  to 
  

   October, 
  inclusive, 
  31.9 
  per 
  cent 
  of 
  the 
  rainfall. 
  The 
  minimum 
  

   monthly 
  runoff 
  was 
  in 
  August, 
  which 
  shows 
  only 
  19.2 
  per 
  cent 
  

   of 
  the 
  rainfall. 
  The 
  rainfall 
  in 
  the 
  month 
  of 
  June, 
  1835, 
  on 
  

   Eaton 
  brook 
  was 
  6.72 
  inches 
  and 
  in 
  July 
  2.74 
  inches. 
  The 
  per- 
  

   centage 
  of 
  runoff 
  to 
  rainfall 
  for 
  June 
  was 
  35.8, 
  whereas 
  for 
  July 
  

   it 
  was 
  41.4, 
  which 
  would 
  indicate 
  that 
  the 
  bulk 
  of 
  the 
  June 
  rain 
  

   must 
  have 
  been 
  at 
  the 
  end 
  of 
  the 
  month. 
  

  

  From 
  the 
  measurements 
  of 
  Madison 
  brook 
  it 
  appears 
  that 
  in 
  

   1835 
  the 
  average 
  runoff 
  for 
  the 
  whole 
  year, 
  including 
  the 
  snow 
  on 
  

   the 
  ground 
  on 
  January 
  1, 
  was 
  44.9 
  per 
  cent, 
  or 
  nearly 
  one-half 
  

   of 
  the 
  rainfall. 
  Mr 
  Jervis 
  points 
  out 
  that 
  on 
  account 
  of 
  the 
  

   storage 
  of 
  the 
  reservoir, 
  the 
  Madison 
  brook 
  record 
  can 
  not 
  be 
  taken 
  

   for 
  the 
  summer 
  months, 
  but 
  that 
  the 
  year 
  should 
  be 
  divided 
  into 
  

   two 
  periods. 
  For 
  the 
  first 
  period 
  he 
  gives 
  the 
  results 
  from 
  Jan- 
  

   uary 
  to 
  May, 
  inclusive, 
  during 
  which 
  the 
  runoff 
  was 
  66.2 
  per 
  

   cent 
  of 
  the 
  rainfall, 
  and 
  for 
  the 
  second 
  from 
  June 
  to 
  October, 
  

   during 
  which 
  the 
  runoff 
  was 
  24.6 
  per 
  cent 
  of 
  the 
  rainfall. 
  During 
  

   the 
  second 
  period, 
  June 
  to 
  October, 
  inclusive, 
  Eaton 
  brook 
  gave 
  

   a 
  runoff 
  of 
  31.9 
  per 
  cent 
  of 
  the 
  rainfall. 
  Mr 
  Jervis 
  explains 
  these 
  

   different 
  results 
  by 
  the 
  different 
  characters 
  of 
  the 
  two 
  districts 
  

   drained. 
  Eaton 
  brook 
  valley 
  is 
  narrow, 
  the 
  area 
  drained 
  steep, 
  

   with 
  a 
  close-textured 
  soil. 
  Madison 
  brook 
  valley, 
  on 
  the 
  other 
  

   hand, 
  is 
  wider, 
  with 
  easy 
  slopes, 
  and 
  the 
  soil 
  is 
  more 
  porous 
  

   than 
  that 
  on 
  Eaton 
  brook. 
  Mr 
  Jervis 
  concludes 
  his 
  discussion 
  

   with 
  the 
  remark 
  that 
  Eaton 
  brook 
  valley 
  would 
  afford 
  more 
  than 
  

  

  iFor 
  Mr 
  Jervis's 
  original 
  report 
  see 
  appendix 
  F 
  to 
  Ann. 
  Rept. 
  Canal 
  Com., 
  

   1835, 
  Ass. 
  Doc. 
  No. 
  65, 
  pp. 
  55-60. 
  Mr 
  Jervis's 
  tables, 
  with 
  extracts 
  from 
  

   the 
  report, 
  are 
  also 
  quoted 
  in 
  the 
  following 
  documents: 
  

  

  (1) 
  Report 
  of 
  F. 
  C. 
  Mills, 
  Chief 
  Engineer 
  Gen. 
  Val. 
  Can., 
  in 
  appendix 
  D 
  

   to 
  Ann. 
  Rept. 
  Can. 
  Com., 
  1837, 
  Ass. 
  Doc. 
  No. 
  80, 
  p. 
  81. 
  

  

  (2) 
  Report 
  of 
  W. 
  H. 
  Talcott, 
  Res. 
  Eng. 
  Gen. 
  Val. 
  Can., 
  1840, 
  Ass. 
  Doc. 
  

   No. 
  96, 
  p. 
  51. 
  

  

  (3) 
  Report 
  of 
  the 
  Regents 
  of 
  the 
  University, 
  1838, 
  Sen. 
  Doc. 
  No. 
  52, 
  pp. 
  

   208-211. 
  

  

  (4) 
  Documentary 
  History 
  of 
  the 
  New 
  York 
  State 
  Canals 
  by 
  S. 
  H. 
  Sweet, 
  

   Dep. 
  State 
  Eng. 
  and 
  Sur., 
  1863, 
  Ass. 
  Doc. 
  No. 
  8, 
  pp. 
  203-204. 
  

  

  