﻿Smithsonian 
  Report 
  1922. 
  — 
  Newell 
  

  

  Plate 
  9. 
  

  

  I. 
  Silt 
  Trap 
  at 
  Head 
  of 
  Canal 
  at 
  Laguna 
  Dam 
  on 
  Colorado 
  River. 
  

  

  2. 
  Steel 
  Reinforcement 
  for 
  Concrete 
  Pipes. 
  

  

  