Lawn Lake Dam

Lawn Lake Dam was an earthen dam in Rocky Mountain National Park that failed on July 15, 1982 at about 6 a.m. The sudden release of 220 million US gallons (830,000 m³) of water resulted in a flash flood that killed three people camping in the park and caused $31 million in damage in and upstream of the town of Estes Park, Colorado.

Lawn Lake was originally a natural lake with a surface area of 16.4 acres (66,000 m²) located at 11,000 feet (3,400 m) in the Rocky Mountains. In 1903 a group of farmers from Loveland built a dam to increase it to 48 acres (190,000 m²) for the purpose of providing water for irrigation in Loveland. Over the years the road that had been cut to permit construction of the dam fell into disrepair and ceased to exist. Because of the dam's remote and difficult location, inspection and repairs lapsed. It is believed that a leaky outlet pipe caused erosion of the dam that led to its failure.

When the dam failed the waters rushed down the Roaring River valley, which falls 2500 feet in 6 miles, at a peak rate of 18,000 cubic feet per second (510 m³/s), scouring a large gully out of the mountain stream and killing one person camping alongside it. At this rate, the lake emptied in about a minute. When the waters reached the broader valley of Fall River at Horseshoe Park they spread out and slowed down, leaving behind a large alluvial fan of debris. The flood continued down Fall River and hit the Cascade Dam which stored water to run a hydroelectric plant about a mile (2 km) downstream. Cascade Dam failed from the onslaught and added its waters to the flood. The Aspenglen campground was destroyed and two campers who returned to recover camping gear lost their lives although rangers had been able to give advance warning. The flood entered the town of Estes Park and caused severe damage to the downtown shops. In Estes Park the flood joined the Big Thompson River and flowed into Estes Lake on the eastern edge of the city. Olympus Dam, part of the Colorado-Big Thompson Project, there withstood the deluge and the flood was halted.

The scar left by the scouring of Roaring River and the alluvial fan at Horseshoe Park are still very apparent 24 years later and will remain for a very long time. Twenty-five years after the accident, the extent of the former reservoir is still clearly evident, and at the mouth of the lake, the start of the Roaring River flows through the location of the former dam.

ee also

[http://www.reporterherald.com/special/story.asp?sp=149&st=5 Reporter Herald Story]