﻿HYDROLOGY 
  OP 
  NEW 
  YORK 
  583 
  

  

  of 
  the 
  stream 
  below 
  the 
  storage 
  point. 
  Obviously 
  the 
  way 
  to 
  

   do 
  this 
  is 
  to 
  plan 
  for 
  an 
  outflow 
  proportional 
  to 
  the 
  catchment 
  

   area. 
  In 
  the 
  present 
  case 
  we 
  have 
  a 
  catchment 
  area 
  at 
  Roches- 
  

   ter 
  of 
  2365 
  square 
  miles, 
  and 
  one 
  of 
  1000 
  square 
  miles 
  above 
  

   Portage, 
  or 
  the 
  area 
  above 
  Rochester 
  is 
  about 
  2J 
  times 
  the 
  area 
  

   above 
  Portage. 
  The 
  minimum 
  regulated 
  flow 
  at 
  Rochester 
  may 
  

   be 
  made 
  2.365 
  times 
  the 
  assumed 
  minimum 
  flow 
  at 
  Portage. 
  

  

  In 
  the 
  foregoing, 
  the 
  statement 
  is 
  made 
  that 
  the 
  outflow 
  

   should 
  be 
  proportional 
  to 
  the 
  catchment 
  area. 
  This 
  is 
  the 
  theo- 
  

   retical 
  view 
  purely, 
  and 
  provided 
  reservoirs 
  can 
  be 
  constructed 
  

   at 
  equally 
  low 
  cost 
  in 
  all 
  parts 
  of 
  a 
  catchment, 
  it 
  is 
  the 
  prefer- 
  

   able 
  principle 
  to 
  follow. 
  But 
  this 
  can 
  seldom 
  be 
  done 
  because 
  

   reservoirs 
  will 
  vary 
  greatly 
  in 
  cost 
  in 
  different 
  parts 
  of 
  a 
  catch- 
  

   ment 
  — 
  they 
  may 
  run 
  all 
  the 
  way 
  from 
  $15 
  to 
  $20 
  per 
  million 
  

   cubic 
  feet 
  stored 
  to 
  from 
  $600 
  to 
  $1000 
  per 
  million 
  cubic 
  feet. 
  

   This 
  practical 
  consideration 
  will 
  modify 
  the 
  theoretical 
  con- 
  

   clusion. 
  

  

  Assuming 
  680 
  cubic 
  feet 
  per 
  second 
  as 
  the 
  flow 
  below 
  which 
  

   the 
  stream 
  will 
  never 
  be 
  allowed 
  to 
  fall 
  at 
  Rochester, 
  we 
  have 
  

   for 
  a 
  reservoir 
  storing 
  7,500,000,000 
  cubic 
  feet 
  a 
  corresponding 
  

   minimum 
  outflow 
  from 
  the 
  reservoir 
  of 
  300 
  cubic 
  feet 
  per 
  second, 
  

   or 
  for 
  a 
  storage 
  of 
  15,000,000,000 
  cubic 
  feet 
  an 
  outflow 
  of 
  457 
  

   cubic 
  feet 
  per 
  second, 
  the 
  latter 
  figure 
  being 
  arrived 
  at 
  by 
  assum- 
  

   ing 
  the 
  maintenance 
  of 
  a 
  minimum 
  flow 
  at 
  Rochester 
  of 
  at 
  least 
  

   1000 
  cubic 
  feet 
  per 
  second. 
  The 
  computations 
  of 
  tables 
  Nos. 
  

   84 
  and 
  85 
  are 
  carried 
  out 
  on 
  this 
  basis. 
  The 
  regulated 
  flows 
  

   for 
  the 
  month 
  of 
  May 
  are 
  greater 
  than 
  for 
  the 
  other 
  months. 
  

   They 
  are 
  also 
  greatest 
  during 
  the 
  months 
  of 
  canal 
  navigation, 
  

   the 
  addition 
  being 
  made 
  in 
  order 
  to 
  provide 
  for 
  the 
  quantity 
  of 
  

   water 
  to 
  be 
  taken 
  for 
  the 
  enlarged 
  Erie 
  canal, 
  which 
  quantity 
  

   has 
  been 
  fixed 
  at 
  80 
  cubic 
  feet 
  per 
  second 
  for 
  every 
  month 
  of 
  

   the 
  navigation 
  season 
  except 
  May, 
  and 
  at 
  177 
  cubic 
  feet 
  per 
  

   second 
  for 
  that 
  month, 
  the 
  excess 
  quantity 
  for 
  the 
  month 
  of 
  

   May 
  being 
  required 
  in 
  order 
  to 
  provide 
  for 
  filling 
  the 
  canal 
  at 
  

   the 
  beginning 
  of 
  the 
  month. 
  

  

  Table 
  No. 
  84 
  shows 
  the 
  effect 
  on 
  the 
  flow 
  of 
  Genesee 
  river 
  from 
  

   June, 
  1894, 
  to 
  November, 
  1896, 
  inclusive, 
  as 
  influenced 
  by 
  the 
  

   storage 
  at 
  Portage 
  of 
  15,000,000,000 
  cubic 
  feet 
  of 
  water, 
  provided 
  

  

  