Hauser Dam
The Hauser Dam ( English Hauser Dam and Hauser Lake Dam ) is or was a dam on the Missouri River, about 22 km northeast of Helena, Montana in the United States. Before today's dam there was a built 1905-1907 dam made of steel, which broke in 1908 and caused a tidal wave and widespread damage. From 1908 to 1911, a new hydroelectric power plant of the PPL Corporation was built, which still exists today and can produce a capacity of 19 megawatts with six turbines.
- 2.1 The tidal wave
The old steel dam
The construction of the dam
The original dam was built by the governor and businessman Samuel Thomas Hauser and his " Missouri River Power Company ". It was a barrage of steel on the foundations of masonry.
JF Jackson, a steel bridge and civil engineer from Wisconsin, constructed the lock and the " Wisconsin Bridge and Iron Company " built it. Martin Gerry was the Bauleiter.Gerry and the Wisconsin Bridge engineer James McKittrick argued several times about the design and Gerry led a number of changes to strengthen the lock.
The dam was 192 m long and 23 m high. The middle 90 m were established on gravel, while the rest was established at both sides on the rock. Therefore, in the middle section sheet piles are driven into the ground of the river bed and the steel of the structure connected to the sheet pile wall. On the sheet pile wall was a triangular foundation of masonry and a cap made of concrete, which should take the dam. The lock itself consisted of inclined steel plates.
A layer of concrete yet been applied to the water side of the lock, and before the lock a 6 m thick and 90 m wide layer of volcanic ash was applied as a seal carpet against seepage to the river bed. The spillway was 150 m wide and 4 m deep. In a hydroelectric power plant 10 horizontally mounted turbines were housed, which contributed 14 megawatts. The total cost of the building amounted to $ 1.5 million. On 12 February 1907, the Hauser Dam was put into operation. It was named after Samuel T. Hauser.
The dam break
On April 14, 1908 about 14:30 clock, failed the Hauser- lock after the water pressure had undermined the masonry foundation. The steel itself remained structurally intact. The first sign of trouble was turbid water, which began to bubble up from the base of the dam near the power plant. An employee who recognized the danger, ran to the power plant and called all in order to run for their lives. About 15 minutes later, the foundation gave way, causing that, the upstream part of the lock gave way and produced a 9 m wide breach. The flowing water through the breach undermined the foundation of further and six minutes later, a 90 m wide piece of the lock lost his grip. The power plant was only slightly damaged. A 7.5 to 9 m high Wasserwoge went down the valley. The remaining parts of the side of the dam, which were anchored in the rock, held back some of the water so that its destructive power was somewhat diminished. In the capital of Montana, Helena, Gerry received a phone call from the operator with the message that the dam had been destroyed. He immediately sent telegrams downriver to all cities and towns, and warned them of the flood. A locomotive of the Great Northern Railway was sent to the city of Great Falls, Montana, to inform all stations on their way from the dam breaks.
The tidal wave
The warnings and the geology of the Missouri below the barrier ensured that no one was killed. The site equipment at the Holter Dam, which was under construction, has been washed away. The later became famous as an actor Gary Cooper and his family, who lived in the Seven Bar Ranch Nine were informed and evacuated in time. The small town of Craig, Montana reached the high tide at 19:00 clock, but the narrow Missourital above the city held back a lot of water and reduced its destructive power. The inhabitants were warned early enough and had fled. First, the press reported that the town was washed away, but that was not so, because only a few huts and the railway station were devastated. The iron bridge by Craig that is usually 7.5 m above the water, was covered with 60 cm of water and it was feared their collapse, but she stopped. The railway tracks of the Great Northern Railway (United States) by Craig to Ulm, Montana were under water. The workers of the Boston and Montana smelter in Great Falls improvised a wing dam to keep the water from the melting shop and blew up a part of the Black Eagle Dam away to continue forward the water, but that was not necessary, because the Missouri here rose to only 2.1 m. The damage was estimated at more than $ 1 million.
At the end of the 20th century fragments of the lock on the banks of the Missouri River could still be found.