﻿312 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  irrigation 
  has 
  been 
  studied, 
  and 
  all 
  the 
  large 
  streams 
  with 
  most 
  of 
  the 
  minor 
  ones 
  

   have 
  been 
  gauged 
  at 
  proper 
  intervals 
  throughout 
  the 
  year, 
  giving 
  a 
  fair 
  approxima- 
  

   tion 
  to 
  the 
  amount 
  of 
  water 
  which 
  may 
  be 
  calculated 
  upon. 
  The 
  work 
  of 
  Mr. 
  Hall 
  

   forms 
  an 
  admirable 
  basis 
  upon 
  which 
  to 
  commence 
  a 
  well-devised 
  system 
  of 
  irrigation 
  

   for 
  this 
  area. 
  

  

  As 
  to 
  the 
  total 
  amount 
  of 
  land 
  which 
  can 
  be 
  reclaimed 
  by 
  means 
  of 
  irrigation, 
  but 
  

   the 
  merest 
  estimates 
  can 
  be 
  made. 
  It 
  is, 
  as 
  was 
  shown 
  above, 
  almost 
  purely 
  a 
  ques- 
  

   tion 
  of 
  the 
  amount 
  of 
  water 
  available. 
  In 
  the 
  first 
  place, 
  we 
  have 
  but 
  few 
  measure- 
  

   ments 
  of 
  the 
  capacities 
  of 
  streams 
  ; 
  and, 
  except 
  in 
  the 
  case 
  of 
  California, 
  they 
  are 
  but 
  

   single 
  measurements, 
  and 
  simply 
  represent 
  the 
  state 
  of 
  the 
  stream 
  at 
  the 
  time 
  of 
  gaug- 
  

   ing. 
  The 
  next 
  day, 
  or 
  the 
  day 
  before, 
  the 
  stream 
  may 
  have 
  carried 
  a 
  very 
  different 
  

   amount 
  of 
  water. 
  In 
  California, 
  as 
  was 
  stated 
  above, 
  a 
  number 
  of 
  streams 
  have 
  been 
  

   gauged 
  at 
  short 
  intervals 
  throughout 
  one 
  year. 
  From 
  ' 
  these 
  measurements 
  with 
  the 
  

   areas 
  of 
  the 
  drainage 
  basins, 
  it 
  may 
  be 
  possible 
  to 
  make 
  rough 
  estimates 
  of 
  the 
  capaci- 
  

   ties 
  of 
  the 
  streams 
  of 
  other 
  parts 
  of 
  the 
  country. 
  

  

  But 
  there 
  are 
  other 
  factors 
  entering 
  to 
  complicate 
  the 
  subject. 
  The 
  first, 
  and 
  most 
  

   important, 
  is 
  the 
  question, 
  What 
  is 
  the 
  "duty" 
  of 
  water, 
  i. 
  e., 
  the 
  amount 
  required 
  to 
  

   irrigate 
  a 
  unit 
  of 
  land, 
  or 
  the 
  number 
  of 
  acres 
  which 
  one 
  cubic 
  foot 
  per 
  second, 
  

   throughout 
  the 
  season, 
  can 
  serve 
  ? 
  This 
  is 
  not 
  a 
  fixed 
  quantity, 
  but 
  differs 
  with 
  dif- 
  

   ferent 
  crops, 
  with 
  different 
  soils, 
  and 
  a 
  variety 
  of 
  other 
  circumstances. 
  Corn 
  requires 
  

   less 
  water 
  than 
  almost 
  any 
  other 
  crop, 
  while 
  oats 
  and 
  grass 
  require 
  the 
  most. 
  Clayey 
  

   lands 
  need 
  less 
  than 
  sandy 
  soils, 
  for 
  very 
  obvious 
  reasons. 
  Very 
  level 
  land 
  requires 
  

   more 
  water 
  than 
  sloping 
  land, 
  as 
  it 
  absorbs 
  more 
  while 
  under 
  irrigation. 
  Crops 
  

   which 
  are 
  sown 
  broadcast, 
  like 
  wheat 
  or 
  oats, 
  require 
  more 
  water 
  than 
  those 
  planted 
  

   in 
  drills, 
  as 
  the 
  more 
  expensive 
  mode 
  of 
  flooding 
  must 
  be 
  resorted 
  to 
  for 
  irrigating 
  

   them. 
  Early 
  sown 
  or 
  planted 
  crops 
  require 
  less 
  water 
  than 
  those 
  planted 
  late, 
  as 
  

   there 
  is 
  more 
  rainfall 
  in 
  the 
  early 
  part 
  of 
  the 
  season, 
  and 
  evaporation 
  is 
  not 
  as 
  rapid. 
  

   Land 
  that 
  has 
  been 
  irrigated 
  requires 
  less 
  water 
  than 
  new 
  land. 
  The 
  reason 
  proba- 
  

   bly 
  is 
  that 
  the 
  soil 
  and 
  subsoil 
  become 
  thoroughly 
  soaked 
  in 
  time, 
  Some 
  even 
  go 
  so 
  

   far 
  as 
  to 
  say 
  that 
  a 
  piece 
  of 
  land, 
  after 
  being 
  irrigated 
  for 
  a 
  number 
  of 
  years, 
  requires 
  

   no 
  further 
  watering. 
  It 
  is 
  possible 
  that 
  this 
  may 
  be 
  true 
  for 
  a 
  season 
  or 
  two, 
  but 
  as 
  

   soon 
  as 
  the 
  water 
  disappears 
  from 
  the 
  subsoil, 
  irrigation 
  will 
  again 
  be 
  necessary. 
  

  

  Major 
  Powell, 
  in 
  his 
  able 
  report 
  on 
  u 
  Lands 
  of 
  the 
  Arid 
  Region," 
  states 
  that 
  the 
  prac- 
  

   tice 
  in 
  Utah 
  allows 
  from 
  80 
  to 
  100 
  acres 
  to 
  the 
  cubic 
  foot 
  per 
  second, 
  which 
  is 
  as 
  high 
  

   a 
  duty 
  as 
  would 
  be 
  expected 
  in 
  Utah, 
  where 
  irrigation 
  is 
  not 
  carried 
  on 
  intelligently 
  

   or 
  economically. 
  In 
  the 
  San 
  Joaquin 
  Valley, 
  of 
  California, 
  where 
  irrigation 
  is 
  car- 
  

   ried 
  on 
  by 
  Americans, 
  and 
  where 
  there 
  is 
  an 
  abundance 
  of 
  water, 
  we 
  naturally 
  find 
  a 
  

   very 
  low 
  duty, 
  ranging 
  from 
  50 
  to 
  150 
  acres 
  per 
  second-foot. 
  In 
  the 
  counties 
  of 
  Los 
  

   Angeles 
  and 
  San 
  Bernardino, 
  however, 
  where 
  most 
  of 
  the 
  ranchmen 
  are 
  Mexicans, 
  who 
  

   have 
  practiced 
  irrigation 
  for 
  centuries, 
  and 
  where 
  there 
  is 
  a 
  great 
  scarcity 
  of 
  water, 
  

   nearly 
  all 
  the 
  streams 
  and 
  springs 
  being 
  used 
  up 
  to 
  their 
  full 
  capacity, 
  we 
  find 
  the 
  

   duty 
  ranging 
  from 
  300 
  to 
  1,500 
  acres 
  per 
  second-foot. 
  To 
  account 
  for 
  this 
  difference 
  

   between 
  two 
  sections 
  of 
  the 
  State, 
  Mr. 
  Hall 
  writes 
  as 
  follows 
  : 
  " 
  The 
  explanation 
  un- 
  

   doubtedly 
  lies 
  in 
  the 
  greater 
  experience 
  acquired 
  by 
  the 
  irrigating 
  communities 
  of 
  Los 
  

   Angeles 
  and 
  San 
  Bernardino 
  Counties, 
  where 
  the 
  art 
  has 
  been 
  practiced 
  longer 
  than 
  in 
  

   other 
  parts 
  of 
  the 
  State, 
  resulting 
  in 
  the 
  acquirement 
  of 
  more 
  skill 
  in 
  the 
  use 
  of 
  water 
  ; 
  

   in 
  the 
  measures 
  which 
  nature 
  has 
  compelled 
  the 
  irrigators 
  to 
  take 
  for 
  the 
  conservation 
  

   and 
  economical 
  distribution 
  of 
  water, 
  and 
  to 
  some 
  extent 
  to 
  the 
  character 
  of 
  the 
  crops 
  

   produced, 
  * 
  * 
  * 
  and 
  last, 
  though 
  by 
  no 
  means 
  least, 
  we 
  find 
  in 
  Los 
  Angeles 
  and 
  

   San 
  Bernardino 
  Counties 
  better 
  irrigation 
  organizations 
  than 
  in 
  the 
  San 
  Joaquin 
  Val- 
  

   ley, 
  which 
  tends 
  to 
  harmonize 
  interests 
  and 
  prevent 
  waste." 
  

  

  A 
  few 
  statistics 
  from 
  the 
  practice 
  in 
  foreign 
  countries 
  will 
  be 
  instructive 
  in 
  this 
  con- 
  

   nection. 
  In 
  Algeria 
  the 
  average 
  duty 
  for 
  cereals 
  is 
  reported 
  as 
  420 
  acres 
  per 
  second- 
  

   foot. 
  In 
  the 
  sub-Himalayan 
  districts 
  of 
  India, 
  the 
  practice 
  is 
  to 
  allow 
  one 
  second- 
  

   foot 
  for 
  218 
  acres. 
  In 
  Granada 
  cereals 
  and 
  vines 
  are 
  irrigated 
  at 
  the 
  rate 
  of 
  240 
  acres 
  

  

  