Sixty years on the South Fork

The U.S. Bureau of Reclamation marked the 60th anniversary of the completion of the Hungry Horse Dam last week. Visitor center host Laurie Lapan baked cupcakes for the occasion.

The Hungry Horse Dam measures 564 feet high from its 330-foot thick base to the 30-foot wide, 2,100-foot long roadway on top. More than 3 million cubic yards of concrete went into the dam’s construction.

The dam holds back about 3.5 million acre-feet of water from the South Fork of the Flathead River in a 34-mile long reservoir — the highest reservoir above sea level in the Columbia River system.

Four 105,000-horsepower turbines in the powerhouse drive four 107-megawatt electrical generators. A total of 1,065 megawatts was produced by downstream hydroelectric dams in 1963-1964 using water originally stored in the Hungry Horse Reservoir.

The dam also protects downstream communities from floods. The great recorded floods in the upper Flathead River system took place in 1894, 1913, 1916, 1922, 1928, 1933, 1948 and 1964. Destruction by the 1964 Flood, which has been called a “500-year flood event,” could have been much worse without the Hungry Horse Dam.

Initial speculation about hydroelectric power development in the Flathead dates back to 1910, when the Anaconda Company considered building a dam for an aluminum smelter in the Flathead.

Congress passed the Hungry Horse Act — sometimes called the “Mansfield Act” for Rep. Mike Mansfield — on June 5, 1944, authorizing the Bureau of Reclamation to build the dam.

Drilling rigs were set up near the site of the new dam two years later for geological testing. General-Shea-Morrison, an alliance of 12 construction companies, submitted the low bid to build the dam on April 7, 1948. It was the second largest contract in Bureau of Reclamation history, exceeded only by the Hoover Dam.

The last bucket of concrete using the cableway system was poured on Oct. 17, 1952. Generator No. 1 began producing power around the same time. And on July 18, 1953, the Selby Drilling Co. finished filling the dam’s 1,000 miles of one-inch cooling water tubing with grout.

The cost of the Hungry Horse Dam when the prime contract ended on July 18, 1953, was $101,965,000 — about $6 million below budget.