﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  109 
  

  

  catchments 
  of 
  40 
  to 
  50 
  inches 
  and 
  with 
  a 
  corresponding 
  runoff 
  

   somewhat 
  less 
  than 
  one 
  half 
  of 
  the 
  rainfall. 
  The 
  minimum 
  runoff 
  

   for 
  these 
  streams 
  is 
  from 
  one 
  fourth 
  to 
  one 
  sixth 
  of 
  the 
  corres- 
  

   ponding 
  rainfall, 
  or 
  from 
  about 
  16 
  per 
  cent 
  to 
  25 
  per 
  cent. 
  

  

  A 
  further 
  class, 
  the 
  far 
  western 
  streams, 
  may 
  be 
  mentioned, 
  in 
  

   which 
  the 
  runoff 
  is 
  only 
  a 
  very 
  small 
  percentage 
  of 
  the 
  rainfall, 
  in 
  

   some 
  cases 
  not 
  more 
  than 
  4 
  per 
  cent 
  to 
  5 
  per 
  cent, 
  or 
  at 
  times 
  even 
  

   less. 
  Probably 
  comprehensive 
  study 
  would 
  further 
  subdivide 
  

   these 
  streams, 
  but 
  the 
  intention 
  at 
  present 
  is 
  to 
  merely 
  call 
  atten- 
  

   tion 
  to 
  some 
  of 
  the 
  more 
  marked 
  peculiarities 
  as 
  a 
  basis 
  for 
  final 
  

   detailed 
  study. 
  

  

  If 
  one 
  takes 
  the 
  streams 
  of 
  the 
  far 
  west, 
  as 
  for 
  instance 
  Loup 
  

   river, 
  in 
  Nebraska, 
  with 
  a 
  catchment 
  area 
  of 
  13,542 
  square 
  miles, 
  

   where 
  the 
  rainfall 
  in 
  1894, 
  observed 
  at 
  24 
  stations, 
  was 
  on 
  an 
  

   average 
  only 
  12.84 
  inches 
  and 
  the 
  runoff 
  of 
  the 
  stream 
  did 
  not 
  

   much 
  exceed 
  1 
  inch, 
  he 
  will 
  find 
  entirely 
  different 
  conditions 
  from 
  

   those 
  above 
  stated. 
  In 
  many 
  cases 
  streams 
  in 
  that 
  locality 
  run 
  

   much 
  less 
  than 
  1 
  inch. 
  The 
  South 
  Platte, 
  at 
  Denver, 
  Colo., 
  in 
  

   1896, 
  with 
  a 
  rainfall 
  of 
  11.84 
  inches, 
  ran 
  0.62 
  inch. 
  The 
  catch- 
  

   ment 
  area 
  at 
  this 
  place 
  is 
  3840 
  square 
  miles. 
  At 
  Orchard, 
  Colo., 
  

   the 
  South 
  Platte, 
  in 
  1898, 
  with 
  a 
  rainfall 
  of 
  about 
  17 
  inches, 
  ran 
  

   0.9 
  inch. 
  The 
  catchment 
  area 
  at 
  this 
  place 
  is 
  12,260 
  square 
  miles. 
  

   The 
  Republican 
  river, 
  at 
  Junction, 
  Nebr., 
  with 
  a 
  rainfall 
  of 
  about 
  

   26 
  to 
  28 
  inches, 
  in 
  1898, 
  ran 
  0.39 
  inch. 
  The 
  catchment 
  here 
  is 
  

   25,837 
  square 
  miles 
  in 
  extent. 
  

  

  The 
  foregoing 
  statements 
  indicate 
  the 
  essential 
  truth 
  of 
  the 
  

   proposition 
  that, 
  broadly, 
  each 
  stream 
  is 
  a 
  law 
  unto 
  itself. 
  Any 
  

   formula, 
  for 
  either 
  maximum, 
  average, 
  or 
  mean 
  runoff, 
  which 
  

   does 
  not 
  take 
  this 
  into 
  account 
  is 
  incomplete. 
  

  

  Estimation 
  of 
  runoff 
  from 
  rain-fall 
  diagrams. 
  Can 
  runoff 
  of 
  

   streams 
  be 
  estimated 
  from 
  diagrams 
  of 
  monthly 
  rainfall? 
  The 
  

   writer 
  has 
  spent 
  considerable 
  time 
  on 
  this 
  problem 
  without 
  arriv- 
  

   ing 
  at 
  any 
  very 
  satisfactory 
  conclusion. 
  For 
  some 
  months 
  such 
  

   a 
  diagram 
  may 
  be 
  made 
  to 
  fit 
  quite 
  closely, 
  while 
  for 
  others, 
  

   differences 
  of 
  as 
  much 
  as 
  2 
  or 
  3 
  inches 
  appear. 
  The 
  conclusion 
  

  

  