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PSNH Hydroelectric plant
wooden penstock
control survey

This Canaan, Vermont hydroelectric plant is just across the Connecticut River from New Hampshire, and only a few miles from the Canadian border. The existing 9 foot diameter wooden stave penstock was originally constructed in the 1920’s and then rebuilt in the 1950’s.

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Water is held back behind a concrete spillway and diverted into the penstock which travels several thousand feet to a power house. The water rotates the turbine producing 1.10 Megawatts of electricity. The penstock was in great need of repair and is slated to be replaced with a 3/8” thick steel pipe.

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The exact location of the pipe was required at the spillway, surge tanks, and power house. Horizontal control was required to be tied into State Plane coordinates (NAD 83). Vertical control was related to NAVD 88. Closed traverses and level loops were performed to locate control points and set brass disks. CAD drawings were prepared to depict all the control and show the existing structures. The end result will allow the new steel pipe to be fabricated offsite and permanent control will allow site construction to flow smoothly.

drawing