﻿414 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  From 
  the 
  date 
  of 
  establishing 
  the 
  station 
  at 
  Dolgeville 
  in 
  1898 
  

   to 
  June 
  1, 
  1899, 
  the 
  discharge 
  was 
  computed 
  from 
  a 
  curve 
  derived 
  

   from 
  Cornell 
  University 
  experiment 
  No. 
  13. 
  From 
  June, 
  1899, 
  

   it 
  has 
  been 
  computed 
  from 
  a 
  revised 
  curve, 
  based 
  on 
  experiments 
  

   by 
  John 
  R. 
  Freeman 
  on 
  a 
  model 
  of 
  the 
  round-crested 
  portion 
  of 
  

   the 
  Croton 
  dam, 
  which 
  corresponds 
  with 
  the 
  section 
  of 
  the 
  Dolge- 
  

   ville 
  dam 
  as 
  regards 
  friction, 
  vertical 
  contraction, 
  siphonage, 
  etc. 
  

   The 
  flow 
  through 
  the 
  turbines 
  has 
  also 
  been 
  computed 
  since 
  

   June, 
  1899, 
  from 
  current-meter 
  measurements 
  in 
  the 
  tailrace, 
  

   instead 
  of 
  the 
  manufacturers' 
  rating 
  tables, 
  as 
  formerly. 
  The 
  

   effect 
  of 
  the 
  changes 
  has 
  been 
  to 
  slightly 
  increase 
  the 
  extremes 
  

   of 
  flow 
  — 
  both 
  as 
  regards 
  high 
  and 
  low 
  water 
  — 
  the 
  flow 
  for 
  the 
  

   mean 
  stage 
  remaining 
  substantially 
  the 
  same. 
  This 
  dam 
  is 
  prac- 
  

   tically 
  watertight 
  and 
  no 
  allowance 
  is 
  made 
  for 
  leakage. 
  

  

  The 
  headwaters 
  of 
  this 
  stream 
  lie 
  in 
  the 
  horizon 
  of 
  the 
  granites 
  

   and 
  gneisses. 
  It 
  crosses 
  the 
  Trenton 
  group 
  and 
  the 
  Hudson 
  river 
  

   shales. 
  

  

  Discharge 
  measurements 
  of 
  West 
  Canada 
  creek. 
  Measurements 
  

   of 
  West 
  Canada 
  creek 
  have 
  been 
  made 
  at 
  Middleville 
  at 
  the 
  timber 
  

   dam 
  of 
  the 
  Nelson 
  Knitting 
  Company, 
  which 
  supplies 
  power 
  to 
  

   four 
  mills. 
  Aside 
  from 
  an 
  ice 
  slide, 
  the 
  crest 
  of 
  this 
  dam 
  is 
  nearly 
  

   level. 
  The 
  leakage 
  of 
  the 
  dam 
  is 
  taken 
  at 
  50 
  cubic 
  feet 
  per 
  second, 
  

   although 
  the 
  leakage 
  is 
  stated 
  to 
  have 
  increased 
  so 
  much 
  during 
  

   1901 
  as 
  to 
  lead 
  to 
  the 
  abandonment 
  of 
  the 
  station. 
  The 
  following 
  

   cut 
  shows 
  cross-sections 
  and 
  profile 
  of 
  this 
  dam 
  : 
  

  

  El. 
  10 
  1.50 
  

  

  '//////////A 
  

  

  Stone 
  

   Wall 
  2 
  

  

  El. 
  101.60 
  

  

  y////////;//, 
  

  

  Timber 
  

   Crib 
  

  

  f//////////////^^^^^^ 
  

  

  Fig. 
  32 
  Cross-sections 
  and 
  profile 
  of 
  dam 
  on 
  West 
  Canada 
  creek 
  at 
  

   Middleville. 
  

  

  