Alpena municipal water pipe clog removed
Trending
ALPENA -- A clog in a portion of an intake line at the Alpena water plant has been located and cleared.
Divers contracted by the city found that lines that carry chemicals to help prevent an invasive species from getting into the pipe failed and dammed up one of the two intake pipes that draw water into the plant, City Engineer Steve Shultz said in a written report to the Alpena Municipal Council.
"We estimate that the lines were installed in the early 1980's and were used to feed a chemical to reduce and inhibit zebra mussels from collecting at the intake openings," Shultz said in his report. "These lines were installed within the intake pipe and became dislodged from their anchors at some point, floated down the pipe and gathered up, creating the blockage between the internal and external intakes. In addition, with the lines not working, mussels began to collect at the intake openings creating further blockage."
Early last month, the council voted to spend up to $200,000 to have the water intake line at the city water plant inspected for a suspected blockage.
The city hired the Brownsville, Wisconsin-based Michels Construction Inc., which moved a barge offshore of Starlite Beach while its crews worked on the pipe.
Michels workers collected and disposed of all the feed lines and cleared any substantial buildup of sand and zebra mussels that they found, Shultz said.
Officials at the city water plant typically close the external line -- which goes 2,000 feet into Lake Huron -- for the winter months. During those months, the city utilizes a lift that is 1,000 feet from shore. An internal riser is opened to prevent interruption of water supply by ice or treatment concerns created by excess sediment in the water coming into the plant.
The clogged pipe did not impede the water supply to customers or impact the safety of the water, Shultz said in October.
City employees tried to locate and correct the blockage on their own, but were unable to do so and outside help was needed, Shultz said.
"After attempting a few different methods to open the external intake, city staff met to discuss options and develop a course of action to inspect the pipe to determine what caused the blockage," Shultz said. "Sometimes, we can dislodge the sand and stuff that comes in by simply blowing water back out, but we weren't able to do that this time."