Laurel Run Dam
Encyclopedia
The Laurel Run Dam, also known as Laurel Run Dam No. 2, was an earthen embankment dam
that failed during the 1977 Johnstown flood. It had the largest reservoir of seven dams to fail between July 19 and 20, 1977 and caused the most fatalities of the two that did. The dam failed in the early morning of July 20 after period of heavy rain, causing 101 million USgals (382,326.6 m³) of water to flood downstream Tanneryville, killing 40 people.
. Laurel Run and Wild Cat Creeks were initially selected as sources and a dam was constructed on Laurel Run Creek in 1869 that impounded the 9 million USgals (34,068.7 m³) Laurel Run reservoir No. 1. Water was transferred from the reservoir through an 18,000-foot 16-inch cast iron pipe to Main and Market Streets in the old Johnstown Borough. Due to contamination and larger reservoirs being built, the Laurel Run reservoir No. 1 was abandoned in 1910.
After the Saltlick Reservoir was completed, workers and equipment were moved to construct the new Laurel Run reservoir No. 2 in 1915. The dam and reservoir were complete in 1919 and held a capacity of 101 million USgals (382,326.6 m³) of water. The dam was also designed for future enlargement.
. The Laurel Run Dam was over-topped with water which eroded its structure. Six other dams failed that day, four were small and two were minor in size. The Sandy Run Dam failure killed five people and was the only other failure to cause deaths.
Embankment dam
An embankment dam is a massive artificial water barrier. It is typically created by the emplacement and compaction of a complex semi-plastic mound of various compositions of soil, sand, clay and/or rock. It has a semi-permanent waterproof natural covering for its surface, and a dense, waterproof...
that failed during the 1977 Johnstown flood. It had the largest reservoir of seven dams to fail between July 19 and 20, 1977 and caused the most fatalities of the two that did. The dam failed in the early morning of July 20 after period of heavy rain, causing 101 million USgals (382,326.6 m³) of water to flood downstream Tanneryville, killing 40 people.
History
During the 1860s, the Johnstown Water Company was planning new infrastructure to meet the municipal water needs of Johnstown, PennsylvaniaJohnstown, Pennsylvania
Johnstown is a city in Cambria County, Pennsylvania, United States, west-southwest of Altoona, Pennsylvania and east of Pittsburgh. The population was 20,978 at the 2010 census. It is the principal city of the Johnstown, Pennsylvania, Metropolitan Statistical Area, which includes Cambria County...
. Laurel Run and Wild Cat Creeks were initially selected as sources and a dam was constructed on Laurel Run Creek in 1869 that impounded the 9 million USgals (34,068.7 m³) Laurel Run reservoir No. 1. Water was transferred from the reservoir through an 18,000-foot 16-inch cast iron pipe to Main and Market Streets in the old Johnstown Borough. Due to contamination and larger reservoirs being built, the Laurel Run reservoir No. 1 was abandoned in 1910.
After the Saltlick Reservoir was completed, workers and equipment were moved to construct the new Laurel Run reservoir No. 2 in 1915. The dam and reservoir were complete in 1919 and held a capacity of 101 million USgals (382,326.6 m³) of water. The dam was also designed for future enlargement.
1977 failure
On the night of July 19, 1977, heavy rains drenched the Johnstown area; at 2:35 A.M. on July 20, the Laurel Run Dam failed. The resulting flood killed 40 people, destroyed 9 homes, and damaged 19 others in downstream Tanneryville. Most residents were asleep at the time and there was no warning system in place along the narrow 3 miles (4.8 km) valley below the dam. In addition, the rain and night-time conditions limited any escape. Overall, the failure caused in damages (US$ million in ). The Laurel Run Dam was over-topped with water which eroded its structure. Six other dams failed that day, four were small and two were minor in size. The Sandy Run Dam failure killed five people and was the only other failure to cause deaths.
Aftermath
After the events of July, 1977, the Laurel Run Dam was never rebuilt by the Johnstown Water Authority. In 1990, the land below and including the site of the dam was designated the "Laurel Run Park" by West Taylor Township. Today, the exact site of the dam is now a grassy field scattered with planted trees and a park bench near the creek. The area that was the reservoir is now a wetlands area filled with various plants and animals.See also
- South Fork DamSouth Fork DamThe South Fork Dam was located on Lake Conemaugh, an artificial body of water located near South Fork, Pennsylvania, United States. On May 31, 1889, the South Fork Dam failed catastrophically and 20 million tons of water from Lake Conemaugh burst through and raced 14 miles downstream, causing the...
– Built in 1853, its failure caused the 1889 Johnstown FloodJohnstown FloodThe Johnstown Flood occurred on May 31, 1889. It was the result of the catastrophic failure of the South Fork Dam situated upstream of the town of Johnstown, Pennsylvania, USA, made worse by several days of extremely heavy rainfall...
. - Dam failure