page_title: Salmon Creek Dam
section_title: Construction
hierarchical_section_title: Salmon Creek Dam / Construction
caption_attribution_description: English: Close View of Salmon Creek Arch dam
context_page_description: The Salmon Creek Dam is a concrete arch dam on the Salmon Creek, 3 miles northwest of Juneau, Alaska. Built in 1914, it is the world's first constant-angle arch variable radius dam. Since it was built, over 100 such dams have been constructed all over the world.
  The dam was built by the Alaska-Gastineau Mining Company to meet the electrical energy needs for mining operations. The dam continues to be fully functional for hydroelectric generation, as one of the drinking water sources to Juneau city and for aquaculture and fishing. When built, adoption of the constant arch design for the dam reduced costs by 20% because less concrete was needed to construct the dam. Of the two hydroelectric power stations built at the initial stage – the latter one is still in use after a new powerhouse was built adjoining the old one – it produces the inexpensive electricity in Alaska while meeting 10% of the energy needs of Juneau city. When built, the dam and its two power plants were considered engineering wonders. Both are operated and maintained by the Alaska Electric Light & Power.
context_section_description: Based on the plans prepared for the concrete arch dam and the two power stations, construction was started in May 1912. Construction of the lower power house on the shore at the confluence of Salmon Creek with Gastineau Channel was initiated first; a transmission line was erected from here to the mines in March 1913 and the construction of the dam was started in April 1913. Construction facilities for the dam were established upstream where aggregates (fine and coarse) were produced by crushing rocks at the crushing plant. The aggregates were mixed in designed proportions with cement and with a small admixture of lime to manufacture concrete for placing on the dam. The first batch of concrete was placed on the dam on July 14, 1913. The dam was completed, over a 13 months period, on August 13, 1914. A concrete quantity of 54,000 cubic yards (41,000 m³) was placed on the dam. Concrete was placed at the rate of 400 cubic yards (310 m³) per day.
  Between 1912 and 1914, two power stations were built to utilize the water stored in the reservoir created by the dam. The first power station, the upper powerhouse titled 'Powerhouse 2', was located 1 mile (1.6 km) below the dam and had an installation of two units of 1.5 MW capacity each operating under a hydraulic head of 600 feet (180 m). The tail waters from this power station was conveyed through a 10,000 feet (3,000 m) long power channel to the second power station titled 'Powerhouse 1' located on the shore of the Gastineau Channel. The power house at this location also had two units of 1.5 MW capacity each operating under a head of 500 feet (150 m). Thus, the total generation from the two power stations was 6,000 kW (8,000 hp). In 1916, the average load on the two power stations was 5,187 horsepower (3,868 kW). Near Powerhouse 1 on the shore, office buildings, machine shops, saw mills, canteen and housing facilities for staff were also built.
caption: Close view of the downstream face of the Salmon Creek Dam.
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