A word about the industrial value of the Mountain may not be without interest in this day of electricity. Within a radius of sixty miles of the head of Puget Sound, more water descends from high levels to the sea than in any other similar area in the United States. A great part of this is collected on the largest peak. Hydraulic engineers have estimated, on investigation, an average annual precipitation, for the summit and upper slopes, of at least 180 inches, or four times the rainfall in Tacoma or Seattle. The melting snows feed the White, Puyallup and Nisqually rivers, large streams flowing into the Sound, and the Cowlitz, an important tributary of the Columbia. The minimum flow of these streams is computed at more than 1200 second feet, while their average flow is nearly twice that total.
The utilization of this large water supply on the steep mountain slopes began in 1904 with the erection of the Electron plant of the Puget Sound Power Company. For this the water is diverted from the Puyallup river ten miles from the end of its glacier, and 1750 feet above sea level, and carried ten miles more in an open flume to a reservoir, from which four steel penstocks, each four feet in diameter, drop it to the power house 900 feet below. The plant generates 28,000 horse power, which is conveyed to Tacoma, twenty-five miles distant, at a pressure of 60,000 volts, and there is distributed for the operation of street railways, lights and factories in that city and Seattle.
Mountain Climbers in Crevasse on Carbon Glacier.
A more important development is in progress on the larger White river near Buckley, where the Pacific Coast Power Company is diverting the water by a dam and eight-mile canal to Lake Tapps, elevation 540 feet above tide. From this great reservoir it will be taken through a tunnel and pipe line to the generating plant at Dieringer, elevation 65 feet. The 100,000 horse power ultimately to be produced here will be carried fifteen miles to Tacoma, for sale to manufacturers in the Puget Sound cities.
Building Tacoma's Electric Power Plant on the Nisqually Canyon.
Upper view shows site of retention dam, above tunnel; middle view, end of tunnel, where pipeline crosses the canyon on a bridge; lower view, site of the generating plant (see p. [21]).