The Lawn Lake Flood
Lake is a natural lake, 11,000 feet high in the mountains of what is now Rocky
Mountain National Park (RMNP) above the town of Estes Park. It was reputedly
named by a hiking party from MacGregor Ranch in the 1880s for its natural
lawn-like shores. In 1903, a group of farmers from Loveland, the Farmer’s
Irrigation Ditch and Reservoir Company, enhanced the natural lake from 16.4
acres to 48 surface acres. The lake was as deep as 35 feet in some places.
Water from Lawn Lake irrigated crops in the Loveland area for years.
Although Lawn Lake was used to irrigate crops for years,
the dam fell out of maintenance because of the six-mile hike that was required
to service it. There had been a road to Lawn Lake when the dam was being built,
it was long since gone by 1982 and no vehicles or heavy equipment could reach
the dam. These factors reduced the frequency of inspections. Over the years of
neglect, a leaky outlet pipe on the upstream side of the dam wore away at the
dam’s structure. Lawn Lake dam was headed for collapse.
The morning of July 15, 1982, was bright and sunny. No
clouds threatened overhead, and no one in Estes Park
that day would have imagined that a devastating flood was about to overwhelm the
town. Shortly after 5:30 a.m., Lawn Lake dam broke, letting loose 674 acre-feet
of water down the Roaring River. A backcountry camper was killed as he slept in
his tent along the river. Surviving campers along the Roaring River estimated
the wall of water to be 25-30 feet high coming down the valley.
the water reached Horseshoe Park, the churning mass slowed down and deposited
much of the debris it has picked up on its six-mile rampage, leaving an alluvial
fan of huge boulders and debris. The flood water was temporarily contained when
it hit the flat, wide floor of Horseshoe Park. Muddied water overran Aspenglenn
campground, a popular destination in Horseshoe Park. Rangers had enough time to
warn people to evacuate, but two campers were killed in the campground when the
course of the flooded Fall River suddenly changed.
The flood water flowed into Cascade Lake, a man-made lake
built by F. O. Stanley in 1909 to store water to
run his hydroelectric plant, located about a mile downstream. Although the
Cascade Lake dam held for a while, it was soon worn down by the four feet of
water that flowed continually over its rim. Finally the second dam broke,
sending 18,000 cubic feet per second of water down the Fall River, on a
collision course with Stanley’s hydroplant and with downtown Estes Park. On an
average summer day today, about 100 cubic feet per second flows in the Fall
River through town.
The furious water hit the plant with a great rage. It
picked up boulders and trees, which acted as battering rams. Flood water picked
up the garage that stood upriver and smashed it into the plant. The water and
debris knocked out the supports from under that largest section of the plant.
The floodwater also destroyed the penstock, which had carried water from the
Cascade Lake dam to the hydro machinery to produce electricity. Only the heavy
equipment inside the plant saved it from being entirely washed away. The plant
would never operate again.
F.O. Stanley’s hydroplant was the first building to fall
victim to the flood. After the water devastated the plant, the Department of
Wildlife’s fish hatchery was similarly destroyed, wiping out 90,000 fish in
the rearing ponds. The slow-moving mass of mud and debris then flowed down
Elkhorn Avenue, carrying camper vans and mobile homes with it and causing huge
amounts of damage to the shops along Estes Park’s main street.
The floodwater eventually met up with the Big
Thompson river and flowed into Lake Estes. Olympus Dam, at the eastern edge of
Lake Estes, was strong enough to hold back the flood water and the wave of
destruction was halted, even though the level of the lake rose by two feet. In
less than four hours, three people were killed and $31 million in public and
private damages, cleanup, and economic loss were incurred.
For more of the story of the Lawn Lake
Flood, click HERE.