ANTHC construction crews make 60,000 pounds of pipe float to keep Sand Point community water safe
December 10, 2018
Recently, ANTHC construction crews installed a new ocean sewer outfall on the coast of Sand Point in the Aleutians East Borough. A sewer outfall is a large pipe anchored to the bottom of the ocean that disperses treated sewage a safe distance away from a community. Built in the 1980s, Sand Point’s original outfall anchors failed and caused it to float twice, making replacement necessary.
Typically, outfalls are assembled 20 feet at a time on the shore from where the pipeline originates. Because of unique site conditions, Sand Point’s new outfall, a 1,000 foot long pipe with bolt-on cast iron weights, weighing over 60,000 pounds, had to be assembled on a beach more than three miles away from where it was to be installed. To tow the pipe into place, the ANTHC team faced the challenge of making something designed to sink, float, to haul it for the three-mile journey and then dropped to the bottom of the ocean.
The team used air-filled rubber tubes shaped like donuts to keep the line on the surface and when the tide and weather were right, launched the outfall into the water. Launch day took a whole day and the better part of the next to get the outfall aligned and sunk to the necessary ocean depth. A local diver swam along the underwater line and helped the ANTHC team deflate the tubes and removed the cap at the end of the outfall. The diver also hooked a towline to the outfall so a local power skiff operator could pull a section of the pipe off an underwater boulder it had settled on. Then the diver confirmed that the entire outfall firmly rested on the bottom.
During the installation, floating not too far away from the new line, was an elderly gentleman in a small skiff quietly observing the work. When an ANTHC engineer struck up a conversation with him, he learned the local Elder was on the crew that sank the original Sand Point outfall in the 1980s and had come out to watch his son help install the new one. To work directly with community members on this or any type of installation is always a rewarding experience, but to have more than one generation involved and interested shows how ANTHC is changing lives of people in the communities we serve far beyond initial project impacts.