﻿400 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  4.5 
  per 
  cent 
  — 
  as 
  water 
  surface. 
  The 
  quantities 
  in 
  this 
  table 
  are 
  

   averages 
  for 
  the 
  calendar 
  months 
  in 
  million 
  gallons 
  per 
  day 
  of 
  

   twenty-four 
  hours. 
  This 
  table 
  is 
  not 
  given 
  here, 
  because 
  it 
  is 
  

   in 
  effect 
  a 
  computation 
  as 
  to 
  the 
  future 
  yield 
  of 
  this 
  basin. 
  

  

  Geologically 
  this 
  catchment 
  lies 
  almost 
  entirely 
  in 
  granites 
  and 
  

   gneisses, 
  although 
  there 
  is 
  a 
  small 
  area 
  of 
  metamorphic 
  Hudson 
  

   formation, 
  consisting 
  of 
  slate, 
  schist 
  and 
  quartzite, 
  and 
  also 
  a 
  

   small 
  area 
  of 
  metamorphic 
  Trenton 
  and 
  calciferous 
  limestones. 
  

  

  The 
  present 
  water 
  supply 
  of 
  New 
  York 
  city 
  is 
  derived 
  from 
  the 
  

   following 
  sources 
  : 
  

  

  1) 
  Catchment 
  of 
  Croton 
  river, 
  thirty- 
  three 
  miles 
  north 
  of 
  New 
  

   York. 
  

  

  2) 
  Catchment 
  of 
  Bronx 
  and 
  By 
  ram 
  rivers, 
  fifteen 
  miles 
  north 
  of 
  

   New 
  York. 
  

  

  3) 
  Catchments 
  of 
  a 
  series 
  of 
  streams 
  on 
  the 
  southern 
  shore 
  of 
  

   Long 
  Island. 
  

  

  4) 
  Ground 
  water 
  which 
  is 
  found 
  underlying 
  a 
  stratum 
  of 
  clay 
  

   on 
  Long 
  Island 
  and 
  on 
  Staten 
  Island. 
  These 
  statements 
  do 
  not 
  

   take 
  into 
  account 
  some 
  unimportant 
  well 
  supplies 
  on 
  Manhattan 
  

   island. 
  

  

  Discharge 
  measurements 
  of 
  Schroon 
  river. 
  This 
  gaging 
  station 
  

   was 
  established 
  at 
  the 
  dam 
  of 
  the 
  Schroon 
  River 
  Pulp 
  Company, 
  

   two 
  miles 
  below 
  Warrensburg, 
  November 
  1, 
  1895, 
  in 
  connection 
  

   with 
  the 
  upper 
  Hudson 
  storage 
  surveys. 
  During 
  ordinary 
  water 
  

   an 
  attempt 
  is 
  made 
  to 
  turn 
  the 
  entire 
  flow 
  of 
  the 
  stream 
  through 
  

   the 
  water 
  wheels, 
  which 
  run 
  twenty-four 
  hours 
  per 
  day, 
  Sundays 
  

   excepted. 
  This 
  is 
  accomplished 
  by 
  the 
  use 
  of 
  flashboards 
  and 
  by 
  

   draft 
  from 
  the 
  storage 
  impounded 
  by 
  the 
  Starbuckville 
  dam. 
  The 
  

   natural 
  flow 
  of 
  the 
  Schroon 
  river 
  is 
  considerably 
  modified 
  by 
  the 
  

   temporary 
  storage 
  of 
  Schroon 
  lake, 
  which 
  has 
  a 
  low-water 
  area 
  of 
  

   9.1 
  square 
  miles. 
  There 
  is 
  a 
  dam 
  at 
  Starbuckville, 
  controlled 
  by 
  

   the 
  Schroon 
  River 
  Pulp 
  Company 
  and 
  which 
  stores 
  from 
  4 
  to 
  5 
  

   feet 
  in 
  depth 
  over 
  Schroon 
  lake 
  area, 
  which 
  is 
  let 
  down 
  as 
  re- 
  

   quired 
  for 
  use 
  during 
  the 
  summer 
  months. 
  This 
  fact 
  explains 
  why 
  

   the 
  Schroon 
  river 
  area 
  apparently 
  yields 
  more 
  water 
  proportion- 
  

   ately 
  in 
  the 
  storage 
  period 
  than 
  the 
  entire 
  Hudson 
  area 
  and 
  less 
  

   in 
  the 
  replenishing 
  period. 
  

  

  