﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  427 
  

  

  cited 
  of 
  this 
  general 
  truth, 
  but, 
  as 
  the 
  object 
  at 
  present 
  is 
  not 
  

   specially 
  to 
  multiply 
  proof 
  on 
  this 
  point, 
  a 
  single 
  one 
  is 
  sufficient, 
  

   although 
  it 
  is 
  proper 
  to 
  remark 
  that 
  the 
  same 
  phenomenon 
  has 
  

   been 
  observed 
  on 
  many 
  other 
  streams. 
  

  

  Torrential 
  and 
  gently 
  floioing 
  rivers. 
  In 
  addition 
  to 
  the 
  classi- 
  

   fication 
  as 
  to 
  concavity 
  of 
  profile, 
  given 
  on 
  a 
  preceding 
  page, 
  rivers 
  

   may 
  be 
  divided 
  into 
  two 
  classes; 
  (1) 
  torrential, 
  and 
  (2) 
  gently 
  

   flowing 
  rivers. 
  The 
  rivers 
  of 
  the 
  first 
  class 
  have 
  considerable 
  

   fall 
  and 
  usually 
  flow 
  over 
  imiDermeable 
  strata, 
  while 
  those 
  

   of 
  the 
  second 
  class 
  flow 
  over 
  alluvium. 
  Many 
  of 
  the 
  

   streams 
  of 
  New 
  York 
  State 
  belong 
  to 
  both 
  classes 
  — 
  in 
  

   their 
  upper 
  reaches 
  they 
  are 
  torrential, 
  while 
  in 
  their 
  

   lower 
  they 
  are 
  gently 
  flowing. 
  This 
  distinction 
  is 
  important 
  to 
  

   bear 
  in 
  mind 
  in 
  treating 
  of 
  the 
  question 
  of 
  floods, 
  because 
  the 
  

   floods 
  of 
  torrential 
  rivers, 
  while 
  high, 
  are 
  of 
  brief 
  duration. 
  

   Gently 
  flowing 
  rivers, 
  on 
  the 
  contrary, 
  have 
  lower 
  floods, 
  but 
  they 
  

   continue 
  for 
  a 
  longer 
  time 
  and 
  are 
  therefore 
  likely 
  to 
  be 
  much 
  

   more 
  injurious. 
  In 
  New 
  York 
  State 
  the 
  torrential 
  streams 
  gener- 
  

   ally 
  flow 
  T 
  through 
  deep 
  valleys 
  and 
  in 
  many 
  cases 
  present 
  excellent 
  

   opportunities 
  for 
  water 
  storage. 
  Usually 
  the 
  valleys 
  of 
  gently 
  

   flowing 
  streams 
  are 
  not 
  suitable 
  for 
  storage 
  reservoir 
  s 
  — 
  the 
  cost 
  

   of 
  the 
  necessary 
  barrage 
  would 
  in 
  many 
  instances, 
  at 
  any 
  rate, 
  

   prove 
  insuperable. 
  1 
  

  

  General 
  principles 
  of 
  river 
  regulation 
  as 
  defined 
  by 
  von 
  Wesc. 
  

   Perhaps 
  as 
  interesting 
  a 
  paper 
  as 
  any 
  is 
  one 
  by 
  Gustav 
  Ritter 
  

   von 
  TVex, 
  rrivy-Councilor 
  to 
  the 
  Emperor 
  of 
  Austria, 
  in 
  which 
  

   the 
  governing 
  principles 
  of 
  river 
  regulation 
  are 
  so 
  clearly 
  set 
  

   forth 
  that 
  one 
  can 
  hardly 
  do 
  better 
  than 
  to 
  give 
  an 
  extended 
  

   extract 
  therefrom. 
  Yon 
  Wex's 
  memoir 
  is 
  limited 
  to 
  a 
  brief 
  

   general 
  summary 
  of 
  the 
  first 
  principles 
  requisite 
  to 
  the 
  successful 
  

   regulation 
  of 
  intractable 
  rivers. 
  The 
  quotation 
  follows 
  : 
  

  

  In 
  every 
  case, 
  first 
  of 
  all 
  the 
  upper 
  course 
  of 
  the 
  river 
  must 
  

   be 
  dealt 
  with 
  separately, 
  and 
  then 
  the 
  lower 
  portion 
  of 
  it, 
  to- 
  

   gether 
  with 
  its 
  mouth, 
  whether 
  it 
  empties 
  itself 
  into 
  an 
  estuary 
  

   or 
  into 
  the 
  open 
  sea. 
  

  

  From 
  long 
  experience 
  it 
  has 
  been 
  ascertained 
  that 
  every 
  

   river 
  or 
  stream, 
  following 
  its 
  natural 
  course 
  through 
  wide 
  tracts 
  

  

  l 
  The 
  Conservancy 
  of 
  Rivers, 
  by 
  Win. 
  IT. 
  Wheeler 
  and 
  Arthur 
  Jacob, 
  

   Troc. 
  Inst 
  C. 
  E., 
  Vol. 
  LXVII. 
  pp. 
  201 
  and 
  20.3. 
  

  

  