Lawn Lake Dam facts for kids
The Lawn Lake Dam was an earthen dam located in Rocky Mountain National Park, United States. It broke on July 15, 1982, around 6 a.m. This event is known as the flood of 1982. A massive amount of water, about 30 million cubic feet (849,000 m3), suddenly rushed out. This caused a fast-moving flood that sadly killed three people who were camping in the park. It also caused about $31 million in damage to the town of Estes Park, Colorado and other areas downstream.
About Lawn Lake
Lawn Lake was naturally a small lake, about 16.4 acres (6.6 ha) in size. It was located very high up in the Rocky Mountains, at about 11,000 feet (3,400 m) above sea level. In 1903, a group of farmers from Loveland decided to build a dam there. They wanted to make the lake much bigger, to about 48 acres (19.4 ha). The main reason for this was to store water for their farms in Loveland, which they used for irrigation.
Why the Dam Broke
Over many years, the road that was built to help construct the dam was not maintained. It became unusable, making it hard to reach the dam. Because the dam was in such a remote and difficult spot, it wasn't inspected or repaired as often as it should have been.
Experts later figured out why the dam failed. The most likely cause was that the lead material sealing a joint between the dam's outlet pipe and a valve had worn out. This allowed water to slowly leak inside the dam. This internal leaking caused the earth-fill dam to erode from the inside. There had been reports of problems during inspections in 1951, 1975, 1977, and 1978.
The Flood's Path
When the Lawn Lake Dam broke, the water rushed down the Roaring River valley. This valley drops about 2,500 feet (760 m) over 6 miles (10 km). The water flowed incredibly fast, at a peak rate of 18,000 cubic feet per second (510 m3/s). This powerful flow carved a huge gully into the mountain stream. One person camping along the river was sadly killed by the flood. The lake emptied completely in about half an hour.
When the flood reached the wider valley of Fall River in Horseshoe Park, the water spread out and slowed down. It left behind a large pile of rocks, mud, and debris called an alluvial fan. The flood then continued down Fall River. It hit the Cascade Dam, which held water for a hydroelectric power plant. The Cascade Dam also broke, adding its water to the already massive flood. The Aspenglen campground was destroyed. Sadly, two campers who went back to get their gear lost their lives. Park rangers had not been able to warn them enough about the danger.
The flood then entered the town of Estes Park. It caused severe damage to 177 businesses in the downtown area. This was about 75 percent of all the businesses in Estes Park. In Estes Park, the flood joined the Big Thompson River and flowed into Lake Estes. The Olympus Dam, which is part of the Colorado-Big Thompson Project, was able to hold back the huge amount of water. This stopped the flood from causing more damage downstream.
What Happened After
Even many years later, the path of the flood is still very clear. The deep gully carved by the Roaring River and the large pile of debris in Horseshoe Park can still be seen. Twenty-five years after the dam broke, you could still clearly see how much bigger Lawn Lake used to be. The Roaring River now flows through the exact spot where the dam once stood.
Because of the Lawn Lake Dam failure, other old dams in the park were removed. These included dams at Pear Reservoir, Bluebird Lake, and Sandbeach Lake.
Images for kids
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The mouth of Lawn Lake (where the dam was) in July 2007, 25 years after the accident.
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Lawn Lake in 2007, 25 years after the accident. You can still see where the lake used to be bigger.
