﻿422 
  XEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  an 
  average 
  runoff 
  over 
  a 
  large 
  district 
  of 
  country, 
  including 
  the 
  

   usual 
  varieties 
  of 
  soil, 
  while 
  Madison 
  brook 
  Avould 
  probably 
  not 
  

   differ 
  materially 
  from 
  the 
  general 
  average 
  in 
  this 
  State. 
  

  

  In 
  his 
  documentary 
  history 
  of 
  the 
  New 
  York 
  State 
  canals, 
  1 
  

   S. 
  H. 
  Sweet 
  analyzes 
  Mr 
  Jervis's 
  measurements 
  of 
  discharge 
  of 
  

   Eaton 
  and 
  Madison 
  brooks 
  and 
  points 
  out 
  several 
  probable 
  errors, 
  

   specially 
  in 
  the 
  Madison 
  brook 
  result, 
  where 
  because 
  the 
  measure- 
  

   ments 
  indicate 
  only 
  what 
  Avas 
  actually 
  discharged 
  through 
  the 
  

   sluice 
  pipes 
  each 
  day 
  instead 
  of 
  what 
  drained 
  off 
  from 
  the 
  valley, 
  

   he 
  concludes 
  that 
  the 
  real 
  drainage 
  of 
  the 
  Madison 
  brook 
  area 
  in 
  

   1835 
  was 
  about 
  0.518 
  of 
  . 
  the 
  rainfall, 
  instead 
  of 
  0.449, 
  as 
  given 
  

   by 
  Mr 
  Jervis. 
  Inasmuch 
  as 
  the 
  Eaton 
  brook 
  and 
  Madison 
  brook 
  

   measurements 
  have 
  only 
  historical 
  interest 
  at 
  the 
  present 
  time, 
  

   this 
  branch 
  of 
  the 
  subject 
  is 
  not 
  here 
  pursued 
  at 
  length. 
  So 
  far 
  

   as 
  can 
  be 
  learned 
  the 
  measurements 
  of 
  these 
  two 
  streams 
  by 
  

   Mr 
  Jervis 
  were 
  the 
  first 
  systematic 
  measurement 
  of 
  the 
  runoff 
  of 
  

   streams 
  in 
  the 
  United 
  States. 
  

  

  Geologically 
  Eaton 
  and 
  Madison 
  brooks 
  lie 
  in 
  the 
  horizon 
  of 
  

   the 
  Hamilton 
  shales. 
  

  

  MAXIMUM 
  AND 
  MINIMUM 
  FLOAV 
  OF 
  STREAMS 
  

  

  The 
  maximum 
  Aoav 
  of 
  a 
  stream 
  is 
  merely 
  another 
  name 
  for 
  

   flood-floAV, 
  and 
  since 
  floods 
  are 
  very 
  destructive 
  in 
  New 
  York 
  the 
  

   general 
  causes 
  may 
  be 
  briefly 
  considered. 
  

  

  A 
  typical 
  New 
  York 
  stream 
  rises 
  in 
  the 
  hills 
  and 
  mountainous 
  

   country 
  at 
  the 
  sides 
  of 
  the 
  valleys 
  and 
  flows 
  down, 
  with 
  declivities 
  

   steepest 
  at 
  the 
  headwaters 
  and 
  in 
  its 
  lateral 
  tributaries, 
  the 
  main 
  

   stream 
  growing 
  flatter 
  toward 
  its 
  mouth. 
  The 
  profile 
  of 
  nearly 
  

   all 
  New 
  York 
  streams 
  is 
  therefore 
  roughly 
  concave 
  in 
  form. 
  

  

  Streams 
  having 
  a 
  concave 
  profile 
  are 
  ordinarily 
  divided 
  into 
  

   three 
  portions, 
  as 
  follows 
  : 
  

  

  1) 
  The 
  upper 
  or 
  torrential- 
  portion, 
  where 
  erosion 
  is 
  active 
  and 
  

   in 
  excess 
  of 
  deposition. 
  

  

  2) 
  The 
  normal 
  portion, 
  where 
  erosion 
  and 
  deposition 
  are 
  about 
  

   equal 
  and 
  the 
  stream 
  is 
  neither 
  lowering 
  nor 
  raising 
  its 
  bed. 
  

  

  3) 
  The 
  alluvial 
  portion, 
  Avhere 
  deposition 
  exceeds 
  erosion 
  and 
  

   the 
  bed 
  is 
  gradually 
  being 
  raised, 
  and 
  Avhere 
  also 
  this 
  raising 
  of 
  

  

  ^nn. 
  rept. 
  State 
  Engineer 
  and 
  Surveyor 
  for 
  1802. 
  

  

  