﻿U. 
  S. 
  B. 
  F.— 
  Doc. 
  805 
  

  

  Plate 
  IV. 
  

  

  CONDITION 
  BELOW 
  THE 
  DAM 
  WITH 
  SIX 
  SPILLWAYS 
  OPEN. 
  NORMALLY 
  A 
  MUCH 
  GREATER 
  

   NUMBER 
  OF 
  SPILLWAYS 
  ARE 
  IN 
  USE. 
  

  

  On 
  the 
  outer 
  side 
  of 
  the 
  fir.st 
  nnd 
  lust 
  spilUviiys 
  of 
  such 
  a 
  group 
  an 
  eddy 
  draws 
  into 
  the 
  spill- 
  

   way 
  streams 
  a 
  portion 
  of 
  the 
  slack 
  water 
  at 
  base 
  of 
  dam. 
  (See 
  observations 
  described 
  in 
  

   .\ppendix, 
  p. 
  20.) 
  

  

  