﻿428 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  of 
  level 
  country, 
  invariably, 
  if 
  the 
  banks 
  consist 
  of 
  deposits 
  of 
  

   earth 
  or 
  gravel, 
  attacks 
  them, 
  the 
  lighter 
  particles 
  being 
  carried 
  

   away, 
  the 
  heavier 
  being 
  deposited 
  in 
  the 
  bed 
  of 
  the 
  stream, 
  so 
  

   that 
  in 
  course 
  of 
  time 
  its 
  width 
  increases 
  while 
  its 
  depth 
  de- 
  

   creases, 
  and 
  at 
  the 
  same 
  time 
  islands, 
  sandbanks, 
  bends, 
  creeks 
  

   and 
  by- 
  channels 
  are 
  formed. 
  

  

  In 
  rivers 
  thus 
  left 
  to 
  nature, 
  the 
  fall, 
  mean 
  velocity 
  and 
  

   force 
  of 
  the 
  current 
  are 
  continually 
  decreasing 
  while 
  the 
  river- 
  

   bed 
  is 
  rising; 
  this 
  naturally 
  raises 
  the 
  general 
  water-level 
  

   relatively 
  to 
  the 
  adjoining 
  country, 
  and 
  exposes 
  it 
  to 
  frequent 
  

   inundation, 
  the 
  effects 
  of 
  which 
  are 
  disastrous 
  floods 
  and 
  the 
  

   formation 
  of 
  innumerable 
  branches 
  and 
  by-channels 
  which 
  inter- 
  

   sect 
  the 
  whole 
  country, 
  flooding 
  and 
  swamping 
  it 
  at 
  every 
  rise 
  

   of 
  the 
  river, 
  and 
  rendering 
  it 
  in 
  time 
  unfit 
  for 
  habitation 
  by 
  

   either 
  man 
  or 
  beast. 
  Instances 
  of 
  this 
  kind 
  are 
  at 
  the 
  present 
  

   time 
  to 
  be 
  met 
  with 
  in 
  many 
  parts 
  of 
  the 
  world, 
  notably 
  in 
  Asia, 
  

   Africa 
  and 
  America. 
  

  

  In 
  order 
  to 
  deal 
  effectually 
  with 
  such 
  cases, 
  namely, 
  to 
  abate 
  

   the 
  floods, 
  and 
  to 
  prevent 
  disasters 
  accompanying 
  them, 
  as 
  well 
  

   as 
  the 
  ultimate 
  formation 
  of 
  trackless 
  swamps, 
  the 
  following 
  

   procedure 
  is 
  recommended 
  : 
  

  

  1) 
  A 
  new 
  channel 
  following 
  the 
  course 
  of 
  the 
  valley 
  should 
  

   be 
  carefully 
  laid 
  down 
  by 
  the 
  superintending 
  engineer, 
  either 
  in 
  

   a 
  direct 
  line 
  or 
  with 
  easy 
  bends, 
  and 
  when 
  excavated, 
  the 
  entire 
  

   body 
  of 
  water 
  should 
  be 
  admitted 
  into 
  this 
  new 
  channel, 
  the 
  old 
  

   bed 
  and 
  all 
  by 
  L 
  channels 
  being 
  filled 
  up. 
  

  

  2) 
  Having 
  carefully 
  determined 
  — 
  

  

  a) 
  The 
  discharge 
  per 
  second 
  at 
  low, 
  mean 
  high 
  water 
  level 
  

   of 
  a 
  'Cross-section 
  of 
  the 
  river, 
  either 
  immediately 
  above 
  or 
  imme- 
  

   diately 
  below 
  the 
  portion 
  to 
  be 
  regulated, 
  and 
  

  

  b) 
  The 
  increased 
  fall 
  which 
  the 
  new 
  channel 
  will 
  afford; 
  

   then 
  the 
  sectional 
  area 
  of 
  the 
  new 
  bed 
  must 
  be 
  fixed, 
  according 
  

   to 
  approved 
  hydraulic 
  formulas, 
  so 
  as 
  to 
  allow 
  of 
  the 
  passage 
  of 
  

   either 
  an 
  ordinary 
  or 
  an 
  extraordinary 
  volume 
  of 
  water. 
  

  

  3) 
  The 
  water 
  having 
  been 
  admitted, 
  the 
  next 
  thing 
  is 
  to 
  

   protect 
  the 
  banks 
  by 
  random 
  rubble 
  or 
  by 
  stone 
  pitching 
  in 
  order 
  

   to 
  prevent 
  the 
  action 
  of 
  the 
  current 
  injuring 
  them, 
  or 
  forming 
  

   bends 
  or 
  creeks. 
  

  

  4) 
  After 
  the 
  completion 
  of 
  the 
  above, 
  the 
  old 
  river 
  bed 
  and 
  

   by-channels 
  should 
  be 
  filled 
  up, 
  the 
  land 
  thus 
  reclaimed 
  should 
  

   by 
  degrees 
  be 
  brought 
  under 
  cultivation 
  ; 
  in 
  the 
  same 
  manner 
  the 
  

   marshy 
  tracts 
  exposed 
  hitherto 
  to 
  inundation, 
  and 
  fertilized 
  by 
  

   the 
  deposit 
  therefrom, 
  should 
  be 
  raised 
  by 
  a 
  coating 
  of 
  rich 
  soil. 
  

  

  5) 
  If 
  exceptionally 
  high 
  floods 
  still 
  overflow 
  the 
  banks 
  and 
  

   inflict 
  loss 
  and 
  damage 
  to 
  the 
  freshly 
  cultivated 
  valley, 
  dykes 
  at 
  

  

  