Allegheny River being lowered Monday for work on Lock and Dam 9
The water level in the upper pool at Lock and Dam 9 on the Allegheny River will be lowered Monday while Northbrook Allegheny Hydro LLC replaces flashboards damaged by high water.
Pool 9 will be lowered to six-inches below the dam's crest, and the water level will drop about one foot below the pool's normal level, according to Corps spokesman Daniel Jones. The flashboards — used for increasing the depth of water behind a dam — will raise the water level in the pool by about six inches once installed.
“With this minimal rise and lowering of the pool, it shouldn't affect people's docks,” Jones said. “But we want people to know so they can check on them.”
Though unlikely with a fall and rise of only a foot, a drop in water could leave docks on dry land. When water levels rise, that could break the lines tying a dock to the shore, Jones said.
Chuck Ahlrich, president of Arizona-based Northbrook Energy, expects the work to be completed in a day if weather cooperates — something he said it hasn't done this year.
“It's scheduled to be done on Monday, provided we don't get a torrential downpour over the weekend,” Ahlrich said. “It's a little bit of a trial-and-error process this year. This has been a very unusual year, and river flows have been too high for us to get out there and do it.”
Northbrook is required to install the 2-foot by 15-foot timber and steel boards along the dam as part of its federal licensing agreement, Corps spokesman Jeff Hawk said.
Raising the water levels ensures pool 9 is high enough to accommodate boaters and keeps the levels like they were before hyrdroelectric stations went in in the 1980s, he said. The company removes the flashboards when boating season ends in October.
Julie E. Martin is a staff writer for Trib Total Media. She can be reached at 724-543-1303, ext. 1315 or email@example.com.