﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  117 
  

  

  In 
  these 
  formulas, 
  D=discharge 
  in 
  cubic 
  feet 
  per 
  second 
  ; 
  C=a 
  

   coefficient, 
  depending 
  for 
  its 
  value 
  upon 
  rainfall, 
  soil, 
  topographi- 
  

   cal 
  slope, 
  elevation, 
  size 
  of 
  the 
  stream, 
  shape 
  of 
  the 
  catchment, 
  etc. 
  

   and 
  M=area 
  of 
  the 
  catchment 
  in 
  square 
  miles. 
  

  

  Coefficient 
  table 
  for 
  representative 
  areas. 
  In 
  Mullins's 
  Irri- 
  

   gation 
  Manual 
  there 
  are 
  given 
  tables 
  for 
  the 
  value 
  of 
  the 
  

   coefficients 
  of 
  these 
  two 
  formulas, 
  together 
  with 
  the 
  correspond- 
  

   ing 
  depth 
  in 
  inches, 
  drained 
  off 
  from 
  the 
  given 
  areas, 
  and 
  the 
  dis- 
  

   charges 
  in 
  cubic 
  feet 
  per 
  second. 
  These 
  two 
  formulas 
  are 
  cited 
  

   because 
  they 
  take 
  into 
  account 
  the 
  principle 
  of 
  the 
  sliding 
  coeffi- 
  

   cient, 
  as 
  does 
  the 
  Kutter 
  formula, 
  a 
  principle 
  which, 
  all 
  things 
  

   considered, 
  is 
  the 
  most 
  useful 
  thus 
  far 
  devised. 
  It 
  is 
  true 
  that 
  

   maximum 
  discharge 
  formulas 
  have 
  been 
  devised 
  taking 
  into 
  

   account 
  average 
  slope, 
  depth, 
  and 
  intensity 
  of 
  rainfall, 
  area 
  of 
  

   the 
  mountainous 
  part 
  of 
  the 
  catchment 
  and 
  area 
  of 
  the 
  flat 
  part 
  of 
  

   the 
  same 
  in 
  square 
  miles, 
  and 
  length 
  of 
  stream 
  from 
  source 
  to 
  

   point 
  of 
  discharge. 
  These 
  formulas, 
  however, 
  also 
  involve 
  from 
  

   one 
  to 
  two 
  coefficients 
  and 
  become 
  complicated 
  in 
  use 
  without, 
  it 
  

   is 
  believed, 
  any 
  special 
  gain 
  over 
  the 
  simpler 
  expressions 
  cited. 
  

   The 
  formulas 
  of 
  Dickens 
  and 
  Ryves, 
  which 
  comprise 
  within 
  the 
  

   coefficient 
  C 
  everything 
  included 
  in 
  the 
  more 
  complicated 
  form- 
  

   ulas, 
  were 
  the 
  forerunners 
  of 
  formulas 
  of 
  this 
  class. 
  

  

  Cooley's 
  formulas. 
  In 
  an 
  able 
  paper 
  1 
  Mr 
  George 
  W. 
  Cooley, 
  

   C. 
  E., 
  gives 
  the 
  following 
  formulas 
  for 
  runoff: 
  

  

  For 
  a 
  catchment 
  without 
  lakes, 
  

  

  F 
  = 
  0.841 
  LRC. 
  (16) 
  

  

  For 
  a 
  catchment 
  with 
  large 
  lakes 
  as 
  receiving 
  reservoirs, 
  

  

  F=(R+y^-E)X0.844 
  W. 
  (17) 
  

  

  In 
  which, 
  F 
  = 
  flow 
  in 
  cubic 
  feet 
  per 
  second. 
  

   R 
  ==« 
  precipitation 
  in 
  feet. 
  

  

  L 
  = 
  land 
  surface 
  of 
  catchment 
  in 
  square 
  miles. 
  

   YV=water 
  surface 
  of 
  reservoirs 
  in 
  square 
  miles. 
  

   E 
  = 
  evaporation 
  in 
  feet. 
  

   C 
  = 
  coefficient 
  of 
  available 
  rainfall. 
  

  

  iHydrology 
  of 
  the 
  Lake 
  Minnetonka 
  Watershed, 
  by 
  George 
  W. 
  Cooley, 
  C. 
  

   E. 
  ; 
  Monthly 
  Weather 
  Review, 
  January, 
  1899. 
  

  

  