After reeking havoc along the U.S. Atlantic coastline Hurricane Irene left a wake of unprecedented damage as it made landfall and pounded its way up through northwestern New York and on into Vermont, New Hampshire and Maine. Just North of Albany, New York, near where the Mohawk and Hudson rivers meet, a submarine cable from the Crescent Hydro Power Plant which energized several Erie Canal locks was destroyed by a buoy anchor that became dislodged by a rampaging torrent and undercurrent. When the decision was made to replace the cable it was determined that power should to carried under the river instead of through it again to avoid similar situations in the future.
O’Connell Electric Company hired Turner Underground Installations to drill and install the 1400 linear feet of 6-inch high density polyethylene pipe (HDPE) for carrying the new cable under the Mohawk based on our experience with similar river crossing applications.
Our on-location geological assessment revealed that the river had a 20-foot average water depth at the construction site and a solid rock bottom. Ground conditions for drilling included areas of dense shale and deposits of greywacke, a variety of sandstone with an impressively high compressive strength.
The project was what we refer to as “an in-and-out”, but that doesn’t mean it didn’t come with its share of difficulties. Boring under the Mohawk required use of a wireline guidance system to monitor the drill bit’s progress and to capture and log depth, distance and time data. Environmental concerns surrounding the banks of the Mohawk mandated special measures be taken during our drilling setup as well as for fluid containment, removal and disposal. The mid-winter schedule meant we had low available daylight hours to accomplish work and saw a cold snap that delivered relentless wind chills which had our crew fighting to keep water, slurry and other liquids involved in the process from freezing on a daily basis.
We completed the 1400-foot bore and installation without a hitch in just over a months time. The project marked Turner’s fifteenth major river crossing.