Big Thompson River

Last updated
Big Thompson River
Park Narodowy Gor Skalistych.jpg
The headwaters of the Big Thompson River are in Rocky Mountain National Park.
Location
CountryUnited States
StateColorado
City Loveland
Physical characteristics
SourceRocky Mountains
  coordinates 40°25′41″N105°47′29″W / 40.42806°N 105.79139°W / 40.42806; -105.79139 [1]
  elevation11,310 ft (3,450 m) [2]
Mouth South Platte River
  location
Near Greeley
  coordinates
40°21′16″N104°45′37″W / 40.35444°N 104.76028°W / 40.35444; -104.76028 Coordinates: 40°21′16″N104°45′37″W / 40.35444°N 104.76028°W / 40.35444; -104.76028 [1]
  elevation
4,670 ft (1,420 m) [2]
Length78 mi (126 km) [3]
Discharge 
  locationLoveland [4]
  average72.5 cu ft/s (2.05 m3/s) [4]
  minimum0.48 cu ft/s (0.014 m3/s)
  maximum35,000 cu ft/s (990 m3/s)
Basin features
Tributaries 
  leftNorth Fork Big Thompson River
  rightLittle Thompson River

The Big Thompson River is a tributary of the South Platte River, approximately 78 miles (123 km) long, in the U.S. state of Colorado. It originates in Forest Canyon into Lake Estes, in Estes Park, CO. It includes four crossings/bridges which are listed on the U.S. National Register of Historic Places.

Contents

Course of the river

Big Thompson River in Moraine Park in the Rocky Mountain National Park Big Thompson River Moraine Park.JPG
Big Thompson River in Moraine Park in the Rocky Mountain National Park

The headwaters of the Big Thompson River begin in Forest Canyon within Rocky Mountain National Park in Larimer County, Colorado. The river flows east through Moraine Park to the town of Estes Park. There it is held in Lake Estes by Olympus Dam before being released into the Big Thompson Canyon. The North Fork Big Thompson River also begins in Rocky Mountain National Park, on the northern slopes of the Mummy Range. This tributary flows east, through the town of Glen Haven, where it merges with the Big Thompson River in the town of Drake, in the Big Thompson Canyon.

From Lake Estes, the river descends 1/2 mile (800 m) in elevation through the mountains in the spectacular 25 mi (40 km) Big Thompson Canyon, emerging from the foothills west of Loveland. It flows eastward, south of Loveland across the plains into Weld County and joins the South Platte approximately 5 mi (8 km) south of Greeley. It receives the Little Thompson River approximately four mi (6 km) upstream from its mouth.

Water resources in the Big Thompson River are managed by the Northern Colorado Water Conservancy District as part of the Colorado-Big Thompson Project.

1976 flood

Sign in the Viestenz-Smith Park, demonstrating the maximum height of the flood Big Thompson River Flood Marker.JPG
Sign in the Viestenz-Smith Park, demonstrating the maximum height of the flood

On July 31, 1976, during the celebration of Colorado's centennial, the Big Thompson Canyon was the site of a devastating flash flood that swept down the steep and narrow canyon, claiming the lives of 143 people, 5 of whom were never found. This flood was triggered by a nearly stationary thunderstorm near the upper section of the canyon that dumped 300 millimeters (12 inches) of rain in less than 4 hours (more than 3/4 of the average annual rainfall for the area). Little rain fell over the lower section of the canyon, where many of the victims were.

Memorial to the lives lost in the 1976 Big Thompson Flood located in the town of Drake. 1976 Big Thompson Flood Memorial.jpg
Memorial to the lives lost in the 1976 Big Thompson Flood located in the town of Drake.

Around 9 p.m., a wall of water more than 6 meters (20 ft) high raced down the canyon at about 6 m/s (14 mph), destroying 400 cars, 418 houses and 52 businesses and washing out most of U.S. Route 34. [6] This flood was more than 4 times as strong as any in the 112-year record available in 1976, with a discharge of 1,000 cubic meters per second (35,000 ft³/s).

In 2008, a man who was thought to have died in the flood was found to be alive and living in Oklahoma. Daryle Johnson and his family had rented a cabin east of Estes Park, but left without telling anyone on the morning of July 31. A woman who was researching the flood's victims discovered he was still alive. [7]

This natural-colour image of the lower reaches of Big Thompson Canyon illustrates two of the three natural factors that contributed to the flood's severity: steep terrain and sparse vegetation Big Thompson Canyon, Colorado.jpg
This natural-colour image of the lower reaches of Big Thompson Canyon illustrates two of the three natural factors that contributed to the flood's severity: steep terrain and sparse vegetation

2013 flood

The canyon was just one of the many areas along the Front Range that were devastated in the September 2013 flood. While not as intense as the 1976 flood, the storms that caused the flooding in 2013 still sent enough water down the canyon to wash out the highway in many places. The flood also damaged the US Bureau of Reclamation's Dille Diversion Dam. The biggest infrastructure casualty, however, was the City of Loveland's hydroelectric plant (rebuilt after the 1976 flood); the Idylwilde Reservoir was completely filled with silt and rocks, the Idylwilde Dam broke free of the bedrock, and the hydroelectric plant in the Viestenz-Smith Mountain Park was filled with water and silt. The dam was in the process of being relicensed with the FERC, but it was instead demolished, the dam material and contents of the reservoir being used as fill for highway repairs. The park has since been redone to accommodate the post-flood river channel and to harden it against potential future floods. The city also rebuilt its municipal electric distribution line into the canyon to replace the original 1925 transmission line and remove obsolete distribution equipment.

See also

Related Research Articles

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Larimer County, Colorado County in Colorado, US

Larimer County is a county located in the U.S. state of Colorado. As of the 2010 census, the population was 299,630. The county seat and most populous city is Fort Collins. The county was named for William Larimer, Jr., the founder of Denver.

Estes Park, Colorado A statutory town in Larimer County, Colorado, United States

Estes Park is a statutory town in Larimer County, Colorado, United States. A popular summer resort and the location of the headquarters for Rocky Mountain National Park, Estes Park lies along the Big Thompson River. Estes Park had a population of 5,858 at the 2010 census. Landmarks include The Stanley Hotel and The Baldpate Inn. The town overlooks Lake Estes and Olympus Dam.

Loveland, Colorado Home Rule Municipality in Colorado, United States

The City of Loveland is the Home Rule Municipality that is the second most populous municipality in Larimer County, Colorado, United States. Loveland is situated 46 miles (74 km) north of the Colorado State Capitol in Denver and is the 14th most populous city in Colorado. As of the 2010 census the population of Loveland was 66,859, and in 2019 the population was estimated at 78,877. The city forms part of the Fort Collins-Loveland Metropolitan Statistical Area and the Front Range Urban Corridor. The city's public schools are part of the Thompson R2-J School District.

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Lawn Lake Dam

Lawn Lake Dam was an earthen dam in Rocky Mountain National Park, United States that failed on July 15, 1982, at about 6 a.m., in an event known as the flood of 1982. The sudden release of 30 million cubic feet of water resulted in a flash flood that killed three people camping in the park and caused $31 million in damage to the town of Estes Park, Colorado and other downstream areas.

Horsetooth Reservoir

Horsetooth Reservoir is a large reservoir in southern Larimer County, Colorado, just west of the city of Fort Collins, Colorado. The reservoir sits in the foothills above the town on the western side of the Dakota Hogback, which contains the reservoir along its eastern side. The reservoir runs north-south for approximately 6.5 miles (10 km) and is approximately one-half mile (1 km) wide. It was constructed in 1949 by the Bureau of Reclamation as part of its federal Colorado-Big Thompson Project or "C-BT". Water distribution is currently managed by Reclamation and operated by the Northern Colorado Water Conservancy District. Horsetooth and Carter Lake serve as the two principal reservoirs for water diverted eastward under the continental divide via the C-BT.

Colorado-Big Thompson Project

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Drake, Colorado Unincorporated community in State of Colorado, United States

Drake is an unincorporated community in Larimer County, Colorado located in the Big Thompson Canyon between Estes Park, Colorado and Loveland, Colorado near Rocky Mountain National Park. A U.S. Post Office is also situated in the county ZIP Code 80515. The 2010 population of Drake was 1,010.

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Colorado River Storage Project

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Grand Ditch United States historic place

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Bridge Canyon Dam Dam in Mohave County, Arizona

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Fall River (Larimer County, Colorado)

The Fall River is a 17.1-mile-long (27.5 km) tributary of the Big Thompson River in Larimer County, Colorado. The river's source is near the Alpine Visitor Center in Rocky Mountain National Park. It flows down a canyon and over Chasm Falls before a confluence with the Big Thompson in Estes Park.

Course of the Colorado River

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2013 Colorado floods

The 2013 Colorado floods were a series of natural disasters occurring in the U.S. state of Colorado. Starting on September 11, 2013, a slow-moving cold front stalled over Colorado, clashing with warm humid monsoonal air from the south. This resulted in heavy rain and catastrophic flooding along Colorado's Front Range from Colorado Springs north to Fort Collins. The situation intensified on September 11 and 12. Boulder County was worst hit, with 9.08 inches (231 mm) recorded September 12 and up to 17 inches (430 mm) of rain recorded by September 15, which is comparable to Boulder County's average annual precipitation. This event has also been referred to as the 2013 Colorado Front Range Flood, reflecting a more precise geographic extent in and along the Colorado Front Range mountains.

Marble Canyon Dam Dam in Coconino County, Arizona

The Marble Canyon Dam, also known as the Redwall Dam, was a proposed dam on the Colorado River in Arizona. The dam was intended to impound a relatively small reservoir in the central portion of Marble Canyon to develop hydroelectric power. Plans centered on two sites between miles 30 and 40 in the canyon. At one point a 38-mile (61 km) tunnel was proposed to a site just outside Grand Canyon National Park to develop the site's full power generation potential, reducing the Colorado River to a trickle through the park.

References

  1. 1 2 U.S. Geological Survey Geographic Names Information System: Big Thompson River, USGS GNIS.
  2. 1 2 Google Earth elevation for GNIS coordinates.
  3. Big Thompson River Archived 2008-04-15 at the Wayback Machine , The Columbia Gazetteer of North America. 2000.
  4. 1 2 Water Data Report, Colorado 2003, from Water Resources Data Colorado Water Year 2003, USGS.
  5. "1976 Big Thompson Flood Memorial".
  6. D. Hyndman and D. Hyndman, Natural Hazards and Disasters (Thomson Brooks/Cole, 2006), 270-271.
  7. Flood 'Victim' Found Alive 32 Years Later Archived 2008-08-05 at the Wayback Machine , TheDenverChannel.com. 2008.