﻿HYDROLOGY 
  OF 
  NEW 
  YORK 
  831 
  

  

  The 
  consumption 
  of 
  water 
  from 
  a 
  navigable 
  canal 
  may 
  be 
  taken 
  

   to 
  include 
  the 
  following 
  items 
  : 
  

  

  1) 
  For 
  filling 
  the 
  prism, 
  in 
  case 
  it 
  is 
  emptied 
  for 
  any 
  reason. 
  

  

  2) 
  Quantity 
  required 
  for 
  lockages. 
  

  

  3) 
  The 
  supply 
  for 
  replacing 
  water 
  lost 
  by 
  evaporation. 
  This 
  

   head 
  may 
  be 
  also 
  taken 
  to 
  include 
  the 
  loss 
  by 
  percolation 
  and 
  

   absorption 
  by 
  subsoil 
  and 
  aquatic 
  plants. 
  

  

  4) 
  Loss 
  by 
  leakage 
  as 
  at 
  aqueducts, 
  culverts, 
  lock 
  gates, 
  

   valves, 
  etc. 
  

  

  5) 
  Loss 
  by 
  wastage 
  at 
  spillways. 
  

  

  6) 
  Water 
  required 
  for 
  power 
  to 
  operate 
  lock 
  gates 
  and 
  for 
  

   flushing 
  out 
  boats, 
  barges 
  and 
  timber 
  rafts, 
  as 
  well 
  as 
  for 
  power 
  

   to 
  operate 
  electric 
  lights 
  at 
  the 
  locks 
  during 
  the 
  nights. 
  

  

  7) 
  Quantity 
  required 
  for 
  industrial 
  and 
  agricultural 
  use. 
  

  

  8) 
  Losses 
  by 
  evaporation, 
  percolation, 
  etc. 
  along 
  the 
  feeder. 
  

   This 
  latter 
  quantity, 
  if 
  the 
  feeder 
  is 
  of 
  considerable 
  length, 
  may 
  

   be 
  large 
  and 
  can 
  not 
  be 
  safely 
  neglected 
  in 
  an 
  estimate 
  as 
  to 
  

   water 
  supply. 
  

  

  There 
  is 
  no 
  specific 
  rule 
  for 
  determining 
  water 
  supplies 
  for 
  

   canals. 
  One 
  chief 
  source 
  of 
  loss 
  is 
  percolation, 
  the 
  determination 
  

   of 
  which, 
  in 
  any 
  particular 
  case, 
  is 
  a 
  matter 
  of 
  judgment, 
  based 
  

   on 
  experience. 
  In 
  any 
  case 
  we 
  may 
  assume 
  much 
  less 
  loss 
  with 
  

   good 
  construction 
  than 
  with 
  poor. 
  The 
  safest 
  way 
  to 
  proceed 
  is 
  to 
  

   apply 
  information 
  derived 
  from 
  well 
  attested 
  experiments. 
  

  

  Table 
  No. 
  96 
  gives 
  measurements 
  and 
  estimates 
  of 
  loss 
  of 
  

   water 
  from 
  canals 
  in 
  New 
  York 
  State 
  by 
  evaporation, 
  percola- 
  

   tion, 
  waste, 
  etc. 
  Many 
  of 
  these 
  measurements 
  have 
  been 
  re- 
  

   ferred 
  to 
  in 
  the 
  preceding. 
  

  

  In 
  connection 
  with 
  the 
  barge 
  canal 
  work, 
  a 
  number 
  of 
  gagings 
  

   were 
  made 
  at 
  various 
  points 
  along 
  the 
  Erie 
  canal, 
  as 
  at 
  Lock- 
  

   port, 
  Boonville, 
  Glens 
  Falls 
  and 
  Rochester. 
  Current 
  meter 
  and 
  

   rod 
  observations 
  were 
  also 
  made 
  at 
  Cornell 
  University. 
  It 
  is 
  

   stated 
  in 
  the 
  barge 
  canal 
  report: 
  

  

  Much 
  time 
  was 
  spent 
  in 
  attempting 
  to 
  find 
  a 
  number 
  of 
  fair 
  

   comparisons 
  in 
  the 
  results 
  of 
  the 
  canal 
  gagings 
  made 
  last 
  sum- 
  

   mer 
  (1900), 
  but 
  unfortunately 
  the 
  geological 
  and 
  topographical 
  

   conditions 
  of 
  the 
  levels, 
  or 
  sections, 
  were 
  not 
  sufficiently 
  similar 
  

   to 
  justify 
  the 
  acceptance 
  of 
  any 
  expressions 
  deduced 
  therefrom. 
  

  

  