Stop logs installed at Hoover Dam

Written by: Josh Chavez

A stop log is slowly transported across the tail bay to Hoover Dam’s powerplant ramp on the Arizona side of the Colorado River. <em>Photos by Kelly Conner</em>
A stop log is slowly transported across the tail bay to Hoover Dam’s powerplant ramp on the Arizona side of the Colorado River. Photos by Kelly ConnerOn Sept. 23, Hoover Dam’s hydroelectric mechanics (HEM) went to work placing the stop logs to kick off the FY2017 maintenance season. Stop logs are 9-ton water barricades that stop tail bay water from flowing into the draft tubes.

Once the stop logs are placed in their respective channels, eductors (also known as jet pumps or Venturi pumps) pump all of the water from the draft tubes. The water pressure from the river holds the stop logs in place.

This process of installing the stop logs allows workers to walk around inside the draft tube and the scroll cases, where they can perform inspections and conduct maintenance and repairs as needed.

HEMs Nathaniel Seria and Dennis Cothran remove the rigging gear from the top of the N5 stop log.
HEMs Nathaniel Seria and Dennis Cothran remove the rigging gear from the top of the N5 stop log.

Using the gantry crane, HEM Randy Pryor extracts a stop log from the Nevada side of Hoover Dam.
Using the gantry crane, HEM Randy Pryor extracts a stop log from the Nevada side of Hoover Dam.

Published on October 21, 2016