From The Supply Post Archives: Underwater Logging

Jun 28, 2021 - 5 years ago

In British Columbia, as in other Canadian provinces, vast areas of land surface are being inundated resulting from the construction of Hydro Electric dams.

From The Supply Post Archives - Underwater Logging — Heel boom grapple moving surfaced log to cradle.

The loss from flooding of sometimes large stands of timber and land that might in other ways be productive can be most costly. In addition, such large man-made lakes are most unattractive with their stubble of dead tree-tops protruding from shore to shore, and the recreational possibilities virtually destroyed.

Such a scene can be found at Ootsa Lake, which is located some 150 miles west of Prince George (B.C.) near the northern boundary of Tweedsmuir Park.

Here, in 1952, the Aluminum Company of Canada built their Kenney Dam on the Nechako River. Water rising to a depth of 317 feet at the dam site wrought great geographical changes over a 5,500 square mile drainage area and created a 358 square mile reservoir — or chain of reservoirs. Mountain valleys were flooded and mountain streams became lakes, and small lakes became big lakes — and a great expanse of forest land containing prime stands of spruce, lodgepole pine and hemlock were buried beneath the water.

Some trees were completely covered but tens of thousands still show their heads above the waters of Ootsa, Whitesail, Tahtsa, and Tetachuk Lakes. Total length of the newly created shoreline is about 1,000 miles, and most of it is dotted with tree tops. The tops are rotten and of no value, but beneath the lake surface, timber is as sound and well preserved as when the waters first rose. Estimates taken of the submerged timber are shown at 50,000,000 cubic feet.

A current view of the Nechako Reservoir, which was created by the linking of the rivers and lakes of Ootsa, Intata, Whitesail, Chelaslie, Tetachuck, Tahtsa and Natalkuz, with a surface area of over 90,000 hectares. Photo courtesy Rio Tinto.

For several years, the Bond Brothers, who had been operating a sawmill at 100 Mile House since 1953, and on Hornby Island in Georgia Strait before that, deplored the loss of timber in this flooded area, and worked on a method for reclaiming it. With their own funds and their inventive skills, they designed a self-propelled steel barge, equipped to nip off standing trees at the butt-end as much as 120 feet below the lake surface.

From the British Columbia Forest Service they secured a license which authorized them to harvest timber from the entire Alcan Watershed for the next 10 years. A clause of the agreement states that they will pay the government the stumpage rate normally charged for salvage material. In addition, their contract may be renewed for a further term.

The all important barge to be used in their operations was built in Vancouver. Constructed in two sections and measuring 60 feet by 30 feet, it was trucked to the Kenney Dam site and there assembled and fitted with a diesel power pod, the cutting mechanism, a grappling device for handling the trees after they are brought to the surface, and other vital components. A small second deck was also added to provide living accommodations for the crew.

After its launching and a few minor teething problems remedied, the odd looking craft, light-heartedly christened “Tahtsa Clipper”, was moored eighty miles west, where dense stands of tree-tops extended above the water. Underwater logging was finally underway.

Only two men are required to work all the equipment on the barge while a third operates a small boom boat which tows the bundled logs to a nearly booming ground.

The barge can be moved in any direction by a single fully rotating propeller located on the bottom of the hull. As the floating logging camp approaches a tree-top, a three ton grappling device suspended over the bow by a cable from the heavy steel stanchion, encircles the trunk. An operator then lowers the heavy contrivance to the bottom of the tree on the lake bed by paying out cable from a drum located amidships. During this action, the branches of the tree are broken off leaving a relatively clean trunk.

Within the arms of the heavy grapple is a scissors-like cutting tool which operates horizontally with one arm cutting and the other acting as an anvil. Up to 3,000 pounds per-square-inch hydraulic pressure can be applied to the blade which will cut trees as thick as 28 inches in diameter. The cut is a s clean as that of a saw.

As soon as the tree is separated from its stump, the grapple holds it firmly and brings it to the surface where a hydraulic heel boom loader, operated by the second man, grasps it and loads it into a steel rack slung over the side of the scow. He must secure it quickly, for the portion which has been submerged for nearly 18 years is largely water-logged and will sink quickly, particularly if separated from its dry and buoyant top.

Meanwhile, the barge has moved forward to another tree and is repeating the delimbing, cutting and surfacing procedures. Up to 40 trees can be harvested in an hour and their diameter at the butt-end ranges between 10 and 16 inches.

The rack, consisting of two U-shaped steel arms, holds 25 to 60 trees, depending on their size. Care is taken to add several pieces of dry top for buoyancy and when the cradle is filled, the bundle is tied together by two steel bands before it is set free for towing to the booming ground.

By mid-October 1970, four booms, each containing 75 bundles of logs, had been assembled and towed 80 miles to the Kenney Dam site. There they were taken ashore for sorting, bucking, drying, and the dead tops burned.

Their next job would be to build a sawmill at Vanderhoof some 60 miles away to which the logs would be trucked. Their plan was to continue stock piling their logs while the mill was being constructed during the 1971 season.

A letter just received from Mike Bond describes rather well their present situation and their plans for this summer’s season.

Here are a few quotes — “We have about 3 million feet now stock piled at the Kenney Dam and another million and a half bloating in bundles on the lake. The main problem on the lake has been wind. There are some sheltered areas but not quite enough, and we have experienced some time loss over wind conditions. We are finding, however, that the timber is every bit as good as we had hoped, and the fact is that we are salvaging some timber above the water in 8 foot or 16 foot length in the pine and it is still pretty good, although there is some checking. Our main problem has been money. We had a great deal of difficulty hunting down a source of this stuff, and finally we were able to get a loan from the Industrial Development Bank, but it was too late last year to get ahead far enough with the mill to get it into operation. We are just about where I think the mill will have as high recovery as any in the province. We will be cutting sizes down to 2 by 2 and 1 by 3, and also chipping our slabs.

This summer we intend to use a float equipped aircraft to solve our communication problem, but our very urgent need is to have the Kenney Dam Road from the Kenney Dam to Vanderhoof repaired for this is our life-line to get our timber out and we have asked the Highways Department to assist us in this matter.

At present we are getting our barge in shape and we hope to be operating it on a round-the-clock basis in the summer.

It seems quite a shame in this day and age of timber shortage to see any of it wasted. We believe that if we were given a small subsidy by the acre to clear out areas where it is not economical for us to go, say something under 30 feet, as the timber stick is too short if the water is too shallow. We could, with a subsidy, go into about 16 feet of water, and still salvage some pretty nice timber sticks.”

This article first appeared in Supply Post newspaper, May 1972 issue.

Editor’s Update: In 1995, Alcan’s Kemano Completion Project was cancelled by the provincial government on account of environmental concerns in the Nechako River. A second power tunnel between the reservoir and the powerhouse, intended for use in the project, is scheduled to be completed soon, but will only serve as a backup to the original tunnel. Alcan was purchased by Rio Tinto in 2007.