Colorado-Big Thompson Project
The Colorado - Big Thompson Project is one of the largest and most complex projects for the use of natural resources by the United States Bureau of Reclamation. It consists of more than 120 rivers and 60 reservoirs, which are integrated into a water pipe system that annually about 320 million m³ ( 260,000 acre-feet ) stores water from the Colorado River on the west side of the Continental Divide, is regulated and the Big Thompson River, a tributary of the South Platte River, passes on the east side of the Rocky Mountains. Originally built as an irrigation system for agriculture, it provides today also water in the rapidly growing cities of Fort Collins, Loveland, Longmont, Boulder and Greeley on the east side of the Rocky Mountains. A total of eleven municipalities obtain water for domestic and industrial consumption. It is also used for the production of electricity, the creation of new recreational areas and for its proper destination, the irrigation of about 291,600 ha ( 720,000 acres) of farmland.
- 4.1 irrigation
- 4.2 industrial and municipal consumption
- 4.3 recreation
- 4.4 electricity
History
In 1870, even before the founding of the State of Colorado, the Union Colony was founded with 2,000 members in Greeley. That was the beginning of Community Irrigation in the valley of the South Platte River and the beginning of an era that was in the irrigation for the development of Northeast Colorado is of great importance. The Union Colony began with the construction of irrigation ditches that irrigated from 4860 from the South Platte River ha of land. When in 1900 the capacity of the rivers was exhausted, they began to build dams, to absorb the annual spring flood can. By 1910, they had created everywhere reservoirs, where they could be built inexpensively. The only way to expand the system even more, was the costly diversion of water through the mountains.
During these years, the demand due to the growing population increased for agricultural products. The trend to expand the irrigation system, especially in years with high or normal water volume more and more, led in years with low water level problems in areas that were completely dependent on irrigation.
The idea to divert water from the west side of the Rocky Mountains on the east side, has existed since 1889, when the legislature of Colorado was investigating the possibility of such a project. In 1922, the Colorado River Compact was signed, which regulated the distribution of water between the residents of the upper and the lower reaches of the river. Later, the Boulder Canyon Act provided the funds for the purpose of determining how much land in the Colorado basin could be irrigated, are available. A plan was drawn up, after which water from the Colorado could be diverted to Northeast Colorado, where there was plenty of good farmland, which could be built but not because of lack of water. The states in the upper reaches concluded in 1948 an agreement on the sharing of water, as was the case after the Treaty of 1922.
In November 1938, we began construction of the Green Mountain Dam, the first building for the Colorado - Big Thompson Project. The Green Mountain hydroelectric plant went in May 1943 as the first power station of the project to the grid. In the summer of 1940 began with the construction work at the Alva B. Adams Tunnel and 1941 at the Granby Dam. During the Second World War, the work for the project were very limited. However, you never quite ceased and were continued after the war with great energy. In 1956, the main buildings of the Colorado - Big Thompson project were ready - to the Big Thompson electricity plant, which was completed in 1959.
The system
Green Mountain Reservoir
To ensure irrigation and electricity generation despite senior water rights on the Colorado, the Green Mountain Reservoir was built. The Green Mountain Dam, a 94 m high earth dam with a crest length of 350 m and a volume of 3.3 million m³, dams the Blue River, a tributary of the Colorado, 21 km south-east of Kremmling. Here, the spring high water is stored in order to direct it in the Colorado later and can thereby have all year round water for the project. The storage tank has a total capacity of 189.5 million cubic meters ( 153.639 acre-feet ).
Lake Granby
The main water storage on the west side of Lake Granby. The Granby Dam impounds the Colorado River about 9 km northeast of Granby. The dam was built as compacted earth dam with 91 m height, a crest length of 262 m and a total volume of 2.3 million m³. Additional dikes with a total length of 3,878 m give the reservoir a capacity of 665.8 million cubic meters.
Willow Creek Reservoir
The Willow Creek, a tributary of the Colorado, which is below the Lake Granby, is ( 39 m high, 335 m long) through the Willow Creek Dam dammed for Willow Creek Reservoir with a capacity of 13 million m³. Through a channel the water (about 49 million m³ / year) is directed to the Willow Creek pumping station that it raises to about 53 m. It then also flows into Lake Granby.
The Granby pumping station lifts water from Lake Granby to Granby Pump Canal, which is 3 km away northward transported to Shadow Mountain Lake. The pumping station has three centrifugal pumps with a total capacity of 17 m³ / sec at a pumping height of 56.5 m. The pumping height varies between 26 m and 56.5 m, depending on the water level of Lake Granby.
Shadow Mountain Lake
The Shadow Mountain Lake is formed by the Shadow Mountain Dam, which on the western border of Rocky Mountain National Park, south of Grand Lake impounds Colorado. The Shadow Mountain Dam is an earth dam, which is 19 m high and 938 m long. The Shadow Mountain Lake has a capacity of 22.7 million m³ and with the Grand Lake connected by a channel.
Alva B. Adams Tunnel
From the eastern shore of Grand Lake of the Alva B. Adams tunnel leads north-east under the National Park through to the east side of the Continental Divide. It flows about 7 km southwest of Estes Park. The tunnel has a diameter of 3 m, is 21 km long and has a capacity of 15.7 m³ / sec From the Alva B. Adams tunnel, the water flows into the East Portal Reservoir and then crosses a culvert in the valley of Aspen Creek. A tunnel will direct the Rams Horn Mountain through to a steel pressure pipe in which it falls to 62.5 m deep Marys Lake power station, which is located on the western shore of Lake Mary.
Marys Lake
The original lake was enlarged by embankments to obtain sufficient storage capacity for a uniform flow. From Mary's Lake, the water is transported to the power station on the shores of Lake Estes through the printing system of Prospect Mountain - water line and the Prospect Mountain Tunnel. It falls to 147 m. The Estes - hydro power plant generates with its three generator units have an average capacity of 45,000 kW.
Lake Estes
The Lake Estes ( total capacity of approximately 3.8 million m³) was created by the Olympus Dam (21 m high with a crest length of 595 m), which impounds the Big Thompson River. The storage in Marys Lake and Lake Estes Estes allow the hydropower plant to adapt its performance to the changing course of the day energy consumption.
Flatiron Reservoir
Water from Lake Estes and sometimes occurring flood of the Big Thompson River is transported to the south by the Olympus culverts and tunnels and the Pole Hill Tunnel and channel to a pressure tube, which it 248 m to the Pole Hill power station (about. 33,250 kW average power ) drops. From the Pole Hill Nachspeicherbecken the water flows through the Rattlesnake Tunnel at Pinewood Lake. The Bald Mountain pressure tunnel directs the water into two pressure tubes through which it crashes down 321.5 m for Flatiron power plant and flows into the Flatiron Reservoir. The power plant generates an average power of 71,500 kW. It has two main generators and a 13,000 -horsepower reversible pump, lifts the water from Flatiron Reservoir to a height from 61 to 91.5 m (depending on the water level in Carter Lake ) and long by a 2.25 km pressure line and a tunnel leads in the Carter Lake. It has a maximum power of 10.5 m³ / sec, and is operated with excess energy of the main generators. In times of peak demand, the flow direction is reversed. The pump then operates as a turbine generator and produces electrical power (8,500 kW).
Also in the Flatiron power station allow pros and Nachspeicherung a need for customized operation.
Carter Lake
The Carter Lake was created at an altitude of 1,750 m above sea level in a natural basin in the Foothills by a 65 high Erdamm and two smaller dikes. It has a capacity of 138.4 million cubic meters. At its deepest point it is about 55 m deep. The collected in Carter Lake water is used for irrigation. The St. Vrain supply tunnel leads from Carter Lake south to Saint Vrain Creek at Lyons, where he feeds about 16 cubic meters of water per second, the Little Thompson River receives 17.5 m³ / sec Shortly before the end of the St. Vrain - supply tunnel begins the Boulder Creek Vorsorgungskanal, the average water volume of 5.5 m³ / sec transported. It flows for 25 km southeast near Boulder in Boulder Creek.
Boulder Reservoir
At the lower end of the canal, the city built the Boulder Boulder Reservoir. It is used for storage and water regulation. The 52 km -long South - plate - supply channel brings water from Boulder Creek northeast to the South Platte River.
Horsetooth Reservoir
At Flatiron reservoir divides the system. In another branch, the water flows north through the Charles Hansen Feeder Canal with the natural gradient to Horsetooth Reservoir and the Big Thompson River. The channel provides 26 m³ / sec the Big Thompson River and 15.5 m³ / sec to Horsetooth Reservoir. The Big Thompson water power plant is located approximately 14.5 km to the west of Loveland on the Big Thompson River. It has a power of 4,500 kW. Water that exceeds the needs of the Big Thompson Valley is stored in Horsetooth Reservoir. It is located west of Fort Collins between two mountain ridges. With a capacity of around 187 million cubic meters, it is the main supply for the Poudre Valley, where 50 % of the water of the Colorado - Big Thompson project will be consumed. The reservoir is 10.5 km long and is formed by large earth dams. The Horsetooth Dam closes the northern end of the valley. Soldier Canyon Dam, Dixon Canyon Dam, Spring Canyon Dam and Satanka dyke close the remaining gaps in the Hogback Ridge.
A flow at Horsetooth Dam releases its water into the Charles Hansen Canal, which has a flow rate of up to 42.5 m³ / sec and was built to carry water north to the Cache la Poudre River. Through a series of smaller channels the water in the Poudre Valley is distributed. Also, the municipal water company in Greeley is supplied from here.
A drain at Soldier Canyon Dam supplies water to the Colorado State University in Fort Collins, the Dixon -feeder channel, which is used for agricultural irrigation, to Fort Collins and in rural areas.
Cache la Poudre, Big Thompson River, Little Thompson River, St. Vrain Creek and Boulder Creek are tributaries of the South Platte River, through which the water that has been inherited transported from the western slopes of the Rocky Mountains, in the South Platte River system is fed. This additional water is used for the cultivation of fertile land in the South Platte River Valley.
Operator
The United States Bureau of Reclamation operates all the facilities of the Colorado Big -Thompson project, located on the west side of the Rocky Mountains, and the facilities on the east side up to and including Carter Lake and Horsetooth Reservoir, including power generation, as well as transport and storage of water. The parts of the project that are below Carter Lake and Horsetooth Reservoir are maintained and operated by the Northern Colorado Water Conservancy District.
Provided by the project deliverables
Irrigation
The Colorado - Big Thompson Project supports agriculture in northeast Colorado. In most years, it is only used towards the end of the summer for irrigation. In dry years, however, it is crucial for the economic survival of farmers. Main crops in the area are sugar beets, potatoes, beans, corn, alfalfa, fruits and vegetables. Other agricultural products are poultry, eggs and dairy products. In addition, lambs, pigs and cattle are fattened with the by-products of sugar beet processing.
Industrial and municipal consumption
The supply of the municipalities is an important aspect in the distribution of water. Originally, there were 9 communities together 55.5 million m³ of water. Today, 11 communities are partially or even completely supplied by the project with water. Because of the increasing consumption in the cities provided for the irrigation water is now being supplied to households. The constant availability of water makes this area attractive for a variety of industries with their high consumption.
Recreation
Around 2 million people a year visit the artificial lakes. There is fishing, motor boating, sailing, swimming, camping and hiking here. Trout, salmon, perch and pike-perch are among the fish that live in these cold, clear waters. In winter, ice fishing and snowmobiling are the most popular sports.
Electricity
From the east exit of the Alva B. Adams Tunnel to the Foothills the water falls by about 850 m. Almost every meter of it is used to generate electrical energy. A total of 760 million kWh produced, of which 70 million kWh for the operation of the project (pumps, etc. ) are consumed. The remaining 690 million kWh go to consumers in northern Colorado, eastern Wyoming and western Nebraska. The electricity generated by the project is marketed by the DOE.
- Management of water
- Colorado