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General Description| Plan| Development| Benefits

General Description

The Fryingpan-Arkansas Project is a multipurpose transmountain, transbasin water diversion and delivery project in Colorado. It makes possible an average annual diversion of 69,200 acre-feet of surplus water from the Fryingpan River and other tributaries of the Roaring Fork River, on the western slope of the Rocky Mountains, to the Arkansas River basin on the eastern slope.

Water diverted from the western slope, together with available water supplies in the Arkansas River Basin, provides an average annual water supply of 80,400 acre-feet for both municipal/domestic use and the supplemental irrigation of 280,600 acres in the Arkansas Valley. Total project supplies may be further increased through use and reuse of project water.

The project also includes one powerplant with a generating capacity of 200 megawatts

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The project is divided into two distinct areas: the western slope, located within the Hunter Creek and Fryingpan River watersheds in the White River National Forests at elevations above 10,000 feet, and the eastern slope in the Arkansas Valley. The project consists of facilities designed primarily to divert water from the western slope to the water-short areas of the eastern slope.

There are five dams and reservoirs in the project. Ruedi Dam and Reservoir, on the Fryingpan River, is the only one of these on the western slope; the other four are on the eastern slope. Sugar Loaf Dam and Turquoise Lake, Mt. Elbert Forebay Dam and Reservoir, and Twin Lakes Dam and Reservoir are in the upper Arkansas watershed. Pueblo Dam and Reservoir, the largest reservoir in the project, is on the Arkansas River.

The Western Slope

Ruedi Dam and Reservoir provide storage for replacement and regulation of approximately 100,000 acre-feet of water for the western slope users. This water is used for irrigation, municipal benefits, recreation, and fish and wildlife enhancement.

Seventeen diversion structures on the western slope are used to divert water into the Fryingpan-Arkansas collection system. The project includes nine tunnels with a combined length of 26.7 miles. The collection system is divided into two parts: North and South.

The North Side and South Side Systems collect the runoff from melting snow in the high mountains. The diverted waters of the Fryingpan and Roaring Fork River Basins flow into the inlet portal of the Charles H. Boustead Tunnel. Boustead has a decreed diversion capacity of 1,000 cubic feet per second (cfs) and conveys all the water from the two collection systems through the Continental Divide to Turquoise Lake.

The Eastern Slope

Turquoise Lake and Sugar Loaf Dam are located just east of the Continental Divide, approximately 5 miles west of Leadville, Colorado. The lake provides storage capacity for the regulation of project water flowing from the Boustead Tunnel.

The Mt. Elbert Conduit conveys water from Turquoise Lake to the Mt. Elbert Forebay. The Halfmoon Diversion Dam intercepts the excess flows of Halfmoon Creek for diversion to the Mt. Elbert Conduit. Water delivered to the forebay is used for generation of power in the Mt. Elbert Pumped-Storage Powerplant. Water exits the powerplant into Twin Lakes.

Twin Lakes Dam is approximately 2,500 feet downstream from the original Twin Lakes. From Twin Lakes, project water is released to Lake Creek and the Arkansas River for delivery to project water users upstream of Pueblo Reservoir, or for storage in Pueblo Reservoir.

Project water is released from Pueblo Reservoir to the Arkansas River for irrigation and municipal purposes, to the Fountain Valley Conduit for municipal purposes, to the Bessemer Ditch for irrigation, and to the Pueblo Fish Hatchery for the fishery.

Construction is complete on all of the project features that were initially designed. Features that were authorized but have not been built include the Last Chance Tunnel and the Line Creek Intercept (parts of the western slope collection system); the Clear Creek Dam, Reservoir, and Canal; and the Arkansas Valley Conduit.

Facility Descriptions

Ruedi Dam is on the Fryingpan River about 15 miles east of Basalt, Colorado. It creates a reservoir with a total capacity of 102,373 acre-feet. Ruedi is a rock and earthfill structure that stands about 285 feet high above streambed, has a crest length of 1,042 feet, and contains approximately 3,745,200 cubic yards of material.

The concrete spillway structure has an uncontrolled Ogee crest, a chute section, a stilling basin, and a bridge over the spillway. The spillway has a capacity of 5,540 cubic feet per second. The outlet works, located under the right abutment of the dam, consist of: a hexagonal intake structure with trashracks; a 10-foot-diameter concrete-lined circular tunnel to a gate chamber housing a 5-by-6-foot high-pressure gate; an 11-foot- diameter concrete-lined horseshoe-shaped tunnel with a 76-inch-diameter steel pipe; a control house with two sets of 3.5- by 4-foot tandem gates and an optional outlet to a 76-inch-diameter steel pipe that provides water to the Ruedi Water and Power Authority powerplant. A shaft house and adit give access to the gate chamber of the outlet works and auxiliary works. The capacity of the outlet works is 1,810 cfs.

The auxiliary outlet works consist of an intake structure with trashracks, a 6-foot-diameter concrete-lined circular tunnel to a gate chamber housing a set of 2.5- by 3-foot tandem gates, and a concrete-lined 5-by-6-foot flat-bottom tunnel. The capacity is 600 cfs.

A concrete bypass, consisting of a concrete chute and stilling basin, carries flows of Rocky Fork Creek past the discharge of the spillway and auxiliary outlet.

Collection Systems

The North and South Side Collection Systems are located at elevations of approximately 10,000 feet. The facilities divert and carry water from the Fryingpan and Roaring Fork River Basins to the inlet portal of the Boustead Tunnel, the tunnel that transports water from the collection system through the Continental Divide to the Arkansas River Basin.

North Side Collection System

The North Side Collection System diverts, collects, and transports an average of 18,400 acre-feet of water annually through the facilities on Mormon, Carter, Ivanhoe, Granite, Lily Pad, North Cunningham, MiddleCunningham, and South Cunningham Creeks.

Carter Tunnel is the first collection tunnel on the North Side Collection System. Water is diverted into the tunnel by Carter Diversion Dam through the 300-foot, 42-inch Carter Feeder Conduit to the inlet of the Carter Tunnel. The North Fork Diversion Dam is a drop-inlet structure that diverts North Fork Creek water into the Carter Tunnel by the 280-foot-long North Fork Feeder Conduit. Carter Tunnel is 0.54 mile long and has an 8-foot horseshoe cross-section with a capacity of 130 cfs. Water from Carter Tunnel flows to the Mormon Conduit.

The Mormon Tunnel extends southward from Mormon Creek. The Mormon Feeder Conduit connects the Mormon Creek diversion structure to the intake portal of the Mormon Tunnel. The conduit is a 250-foot-long structure, including a Parshall flume - type measuring device. The tunnel is 1.4 miles long and has an 8.25-foot horseshoe-shaped section and a capacity of 190 cfs. The water from the Mormon Tunnel flows to the Cunningham Tunnel.

The diversion structures on North, Middle, and South Cunningham Creeks are connected to the Cunningham Conduit by feeder conduits which extend to Cunningham Tunnel. The combined length of the three feeder conduits is 2,700 feet, and the Cunningham Conduit is 4,170 feet long. Cunningham Tunnel is 2.86 miles long and has a horseshoe-shaped cross section of two sizes: 8.75 and 7.5 feet. The capacity is 270 cfs. The Cunningham Tunnel feeds into the Nast Tunnel.

Ivanhoe Diversion Dam diverts water from Ivanhoe Creek and the Cunningham Tunnel through the Ivanhoe Creek crossing into the inlet of the Nast Tunnel. Farther south, the Granite Diversion Dam diverts water from Granite Creek through the Granite Siphon to the Granite Adit, which drops the flow into the Nast Tunnel. Lily Pad Diversion Dam also drops its flow into the Nast Tunnel. The Nast Tunnel is 3 miles long and has a circular-shaped section with two diameters: 7.67 and 9.33 feet. The capacity of the tunnel is 360 cfs. The Fryingpan Conduit, which is 2,481 feet long and 84 inches in diameter, conveys flows to the Boustead Tunnel.

South Side Collection System

The South Side Collection System transports an average of 50,800 acre-feet of project water annually from the Fryingpan and Roaring Fork River Basins. The system collects and diverts water from facilities located on No Name, Midway, Hunter, and Sawyer Creeks; on Chapman Gulch; on the South Fork of the Fryingpan River; and on the main stem of the Fryingpan River downstream of Marten Creek.

Hunter Tunnel is 7.6 miles long. It transports the flows diverted at No Name, Midway, and Hunter Creeks to Chapman Gulch at the Chapman Diversion Dam. The capacity ranges from 90 cfs at No Name Creek-the beginning point of the South Side Collection System-to 270 cfs at Chapman Gulch. The tunnel is a semi-horseshoe-shaped structure with two sizes: 8.5 and 7.33 feet.

The No Name, Midway, and Hunter Creek diversion structures are all similar. Each has a sluice gate for bypassing all streamflow when water is not being diverted. When diversions are being made, minimum flow is released through a bypass to maintain the stream. A side overflow section provides for passing floodflows. Flows are diverted through a short flume section to a shaft that drops the water into the Hunter Tunnel.

The Sawyer diversion drop inlet diverts water from Sawyer Lake into the Sawyer Feeder Conduit (3,098 feet in length), which carries the water to Chapman Gulch. Hunter Tunnel and the Sawyer Feeder Conduit both empty into Chapman Gulch, and the water then flows to the Chapman Diversion Dam to be diverted into the Chapman Tunnel. This tunnel is 2.8 miles long, has a 7-foot-wide horseshoe-shaped structure, and has a capacity of 300 cfs.

The South Fork Diversion Dam diverts water from the South Fork of the Fryingpan River to the South Fork Siphon, where it combines with the flow from the Chapman Tunnel and is conveyed by the South Fork Feeder Conduit to the inlet of the South Fork Tunnel. This tunnel is 3.1 miles long, has an 8-foot-wide horseshoe- shaped cross section, and has a capacity of 450 cfs.

The Fryingpan Diversion Dam diverts water into the Fryingpan Siphon, under the Fryingpan River, to the inlet structure of the Boustead Tunnel. At the Boustead Tunnel, flows from the Fryingpan Siphon, the South Fork Tunnel, and the Fryingpan Conduit (part of the North Side Collection System) all come together for transport to the Eastern Slope.

Charles H. Boustead Tunnel

The Charles H. Boustead Tunnel conveys all the water collected in the North and South Side Collection Systems under the Continental Divide to Turquoise Lake. The 10.5-foot-diameter, horseshoe-shaped tunnel is approximately 5.4 miles long. Its decreed capacity is 945 cfs. The Fryingpan Valley control structure at the inlet portal regulates flows entering the Boustead Tunnel. It is a concrete junction structure which contains two overflow weirs (one for each of the collection systems), a baffled-apron wasteway drop structure to return the excess flows to the Fryingpan River, a connection and access hatchway structure to receive the flows from the Fryingpan Feeder Conduit, and a control structure housing a 10.5- by 12-foot radial gate. The entire structure is underground.

Sugar Loaf Dam and Turquoise Lake

Sugar Loaf Dam and Turquoise Lake are east of the Continental Divide on the Lake Fork of the Arkansas River in Lake County, approximately 5 miles west of Leadville. The reservoir storage capacity is 129,440 acre-feet. Sugar Loaf Dam is an earthfill structure. It is 2,020 feet long, rises 135 feet above the streambed, and contains approximately 1,833,700 cubic yards of material.

The spillway has a capacity of 2,920 cfs and consists of a morning-glory intake structure, a 16.5-foot-diameter monolithic concrete conduit, a chute, and a stilling basin. The outlet works consist of an intake structure with trashracks; a 7-foot- diameter concrete conduit with a steel liner; a gate chamber housing a 5- by 6-foot high-pressure gate; an 11-foot-diameter concrete conduit with a steel liner; a 72-inch-diameter steel outlet pipe; a river outlet control house with four 3.5-foot-square high- pressure gates; and a chute and stilling basin discharging to the Lake Fork. The outlet pipe bifurcates into two parallel branches just upstream from the river outlet control house, and each branch leads to two of the control house´s four high- pressure gates.

A short 72-inch-diameter steel branch outlet pipe with a bulkhead is provided upstream from the bifurcation for future use, and as an outlet to the Mt. Elbert Conduit. The capacity of the river outlet is 1,120 cfs, and the capacity of the outlet to the Mt. Elbert Conduit is 370 cfs.

The waters of Turquoise Lake are also retained by an 11-foot-high dike, approximately 6,000 feet northeast of Sugar Loaf Dam. The dike is 475 feet long.

Mt. Elbert Conduit

The Mt. Elbert Conduit conveys project water from Turquoise Lake to the Mt. Elbert Forebay. Water delivered to the forebay is used for the generation of power in the Mt. Elbert Pumped Storage Powerplant. At Halfmoon Creek, additional water is diverted into the conduit for delivery to the Mt. Elbert Forebay. A pipe turnout and conduit deliver supplemental water from the conduit to the Leadville National Fish Hatchery. The conduit is a 90-inch-diameter pipe, 10.7 miles long, and is designed for a flow of 370 cfs from Sugar Loaf Dam to the forebay. It consists of a series of siphon and free-flow conduit reaches.

Halfmoon Diversion Dam

The Halfmoon Diversion Dam intercepts the excess flows of Halfmoon Creek for diversion to the Mt. Elbert Conduit. The diversion dam consists of a concrete spillway overflow structure, earth-wing dike structures, a gated concrete structure to bypass irrigation flows for downstream use, and a heading for a feeder conduit. The Halfmoon Feeder Conduit is a 60-inch-diameter pipe, 3,202 feet long, and delivers the flow diverted at Halfmoon Creek to the Mt. Elbert Conduit. Flow capacity of the feeder conduit is 150 cfs.

Mt. Elbert Forebay Dam and Reservoir

The Mt. Elbert Forebay occupies a saddle on a ridge above Twin Lakes Reservoir. The rolled earthfill forebay dam is about 2,600 feet long and 92 feet high. A 130-foot-long earth dike closes a low saddle at the southwest end of the reservoir. In 1980, the forebay was lined with a 45-mil reinforced chlorinated polyethylene flexible membrane lining material for seepage control.

There is no spillway in the forebay dam. The only outlet is through a channel from the southeast corner of the reservoir that connects to the inlet-outlet structure for the powerplant penstock. However, natural flow into the reservoir is negligible.

Mt. Elbert Powerplant

The Mt. Elbert Pumped-Storage Powerplant is on the north shore of picturesque Twin Lakes, approximately 13 miles southwest of Leadville, at the foot of 14,433-foot Mt. Elbert, Colorado's highest mountain peak. The powerplant was designed with modern architectural lines and is an all-concrete structure equivalent to a 14-story building, although most of the structure is below ground.

Power is generated from water stored in the Mt. Elbert Forebay. The water drops through the penstocks 447 feet, spinning each of two 138,000-horsepower hydroelectric turbine-generators and developing 200,000 kilowatts of electrical power.

To supplement the flow-through water received from Turquoise Lake via the Mt. Elbert Conduit, these generators have been designed to operate as a 170,000-horsepower electric motor that drives the turbines in reverse, pumping the same water back up to refill the forebay. This pumping mode is normally used during the very early morning hours, when power demands are low and surplus low-rate power is received from other generating stations. This pump-back storage principle is advantageous since the generating units can be started quickly and adjustments of power output can be made rapidly to respond to varying patterns of daily and seasonal power demands.

Twin Lakes Dam and Reservoir

Twin Lakes Dam and Reservoir is approximately 13 miles south of Leadville, in Lake County. The reservoir has a total capacity of 141,000 acre-feet. The dam is a zoned, rolled earthfill structure with a height above streambed of 53 feet. The crest of the dam is 30 feet wide and 3,150 feet long.

The spillway is on the left abutment of the dam, and has a capacity of 1,400 cfs. The spillway is an uncontrolled concrete morning-glory inlet structure with a 9-foot-diameter concrete conduit under the dam embankment and a concrete stilling basin. A channel downstream from the stilling basin carries the water to Lake Creek. The outlet works located in the right abutment delivers 3,465 cfs to the creek. The outlet works has an inlet structure with a trashrack, a 12-foot-diameter concrete conduit with steel liner, and a gate-chamber housing a 9-by-12-foot high-pressure gate. A 16.75-foot-diameter horseshoe-shaped concrete conduit containing a 12.0-foot-diameter steel outlet pipe leads from the gate chamber to the river outlet control house where two 6.5-by-8.0-foot high-pressure gates are located. A chute, stilling basin, and a 400-foot-long outlet channel lead to Lake Creek.

Pueblo Dam and Reservoir

The terminal storage facility, Pueblo Dam and Reservoir, is located on the Arkansas River in Pueblo County about 6 miles upstream and west of the city of Pueblo. The reservoir has a total storage capacity of 357,678 acre-feet: 30,355 acre-feet of dead and inactive capacity; 234,347 acre-feet of conservation capacity; 65,952 acre-feet of joint-use capacity; and 27,024 acre-feet of exclusive flood-control capacity.

Pueblo Dam is a concrete dam combined with two earthfill embankment "wings" on the right and left sides of the dam. The concrete dam and massive-head buttress-type spillway is the principal control structure for the reservoir. The concrete section is 1,750 feet wide with a maximum structural height of 250 feet. The spillway has a crest width of 550 feet and was designed for a maximum spill discharge of 191,500 cfs.

The dam has seven outlets in all, six in the concrete portion and one through the right earthfill abutment. The main river outlet works is controlled by two 4-foot-square high-pressure gates, which regulate normal water releases into the river. Additional releases to the river may be made through three separate spillway outlet works, each controlled by two 6-by-6.5-foot high-pressure gates. The south outlet works was designed and constructed to deliver water for municipal and industrial use. It is a multilevel intake structure capable of taking water from the reservoir at different levels, thus providing a degree of control over water temperature and quality. Another multilevel outlet works supplies water to a downstream fish hatchery. The outlet through the right earthfill abutment supplies water to the Bessemer Ditch.

Fountain Valley Conduit

The Fountain Valley Conduit begins at Pueblo Dam and ends near Academy Boulevard about 2 miles south of Colorado Springs. The conduit conveys approximately 20,100 acre-feet of project water annually to the communities of Stratmoor Hills, Widefield, Security, and Fountain. The Fountain Valley Conduit is 45 miles long and ranges from 42 to 14 inches in diameter. It has five pumping plants, two regulating tanks, two surge tanks, and four terminal tanks. The capacity is 31 cfs.
Operating Agencies

The Bureau of Reclamation operates and maintains the dams and reservoirs described here. The U.S. Forest Service manages the recreation, fish and wildlife facilities, and resources at Ruedi Reservoir, Turquoise Lake, and Twin Lakes. At Pueblo Dam and Reservoir, fish and wildlife and recreation resources are under the management of the Colorado Department of Natural Resources.

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The area of the project north and east of the Arkansas River was a part of the Louisiana Purchase in 1803. Following the war with Mexico, Texas claimed the remainder of the project area. Mexican claims to the territory were relinquished in 1845 when Texas entered the Union.

Various Spanish explorers visited the project area during the years 1760-80. Lieutenant Zebulon Pike headed the first official exploration by the United States in 1806-07. Captain John C. Fremont and Captain John W. Gunnison directed later explorations. The first permanent settlements were not established until after the discovery of gold in 1859-61. With the mining boom came immigrants who turned to agriculture to supply foodstuffs for the expanding population. Large cattle ranches appeared as the result of cattle drives from Texas.


Studies by the Bureau of Reclamation on a transmountain diversion project began in 1936. Intensive investigation started in 1941, resulting in a potential planning report in 1947 and 1948, followed by a special report in 1949 and official recommendations in 1951.

A revised planning report under the name "Fryingpan-Arkansas Project" in 1953 led to congressional approval of the project. In September 1959, a report that supplemented House Document No. 187. 83d Congress, 1st session, recommended Ruedi Dam and Reservoir instead of the previously recommended Aspen Dam and Reservoir.


The Fryingpan-Arkansas Project was authorized for construction in 1962 under Public Law 87-590 (77 Stat. 393), which was amended by Public Law 95-586 (92 Stat. 2485) in 1978. Operation of the project is governed by a set of operating principles originally approved by Congress. The State of Colorado and others adopted the operating principles in April 1959, amended December 30, 1959 and amended again December 9, 1960.


Construction of the project began with Ruedi Dam and Reservoir in 1964. Project water for irrigation and municipal and industrial purposes was available in September, 1975. Power was first delivered from the Mt. Elbert powerplant in 1981. Initial deliveries of project water to the Fountain Valley Conduit occurred in the mid-1980s.

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Water diverted from the western slope and regulation of the Arkansas River flows provides supplemental irrigation supplies for 280,600 irrigable acres in the Arkansas Valley. Project water, first delivered in 1975 has enabled farms to sustain and increase the level of agricultural productivity per acre. It permits farmers to diversify the crops produced and to be more responsive to market demands for food and fiber.

Because of the ability to diversify crops and meet peak demands, the value of total crop production of the Arkansas Valley has increased. Major crops grown are alfalfa, corn, sorghum, and sugar beets. Specialty crops such as onions, beans, various nuts, tomatoes, and melons are also grown extensively in the valley.

Municipal and Industrial

Water for municipal and industrial use was developed by the project to supplement existing supplies and was first delivered in 1975. A separate water delivery pipeline system, the Fountain Valley Conduit, begins at Pueblo Dam and conveys water to organizations and communities in the Fountain Creek watershed on the eastern slope.

The cities of Colorado Springs and Aurora have contracted to use the conveyance system of the Fryingpan- Arkansas Project from Turquoise Lake for transportation of municipal water supplies owned by the two cities. Homestake Project water is pumped from Twin Lakes into the Upper South Platte River Basin for delivery to the city water systems.


The Mt. Elbert power generation and transmission system is connected to the Public Service Company of Colorado transmission system at the Malta substation near Leadville. This interconnection with Public Service Company enables Fryingpan-Arkansas Project power to be marketed to Colorado customers through the Western Area Power Administration.

Recreation, Fish & Wildlife

The Bureau of Reclamation has developed recreation facilities throughout the Fryingpan-Arkansas Project in cooperation with the National Park Service, Forest Service, and State and local agencies.

The location of Ruedi Reservoir on the western slope provides an exceptionally beautiful background for swimming, boating, water skiing, fishing, picnicking, camping, and general relaxation. The Forest Service has developed and is managing these recreation activities at Ruedi.

Dominant game fish found in the streams on the western slope include rainbow, brown, cutthroat, and brook trout. Development of Ruedi Dam and Reservoir has increased the available fish habitat in the area, and the Fryingpan River immediately downstream from Ruedi is known as a gold medal fishery. Operation of the dam has exposed about six acres of gravel, which now serve as a brown trout spawning ground, immediately downstream from the dam. The gravel areas and regulated streamflow have improved the fishery through increased natural reproduction and increased recreation opportunities in the immediate area. The most common big game species are deer and elk; black bears are seen occasionally.

Recreation activities at Turquoise Lake include sightseeing, camping, swimming, water skiing, boating, and hunting. Development of the lake has increased the aquatic habitat and surface acreage available for fish. Species in this area include kokanee salmon and rainbow, brown, and lake trout. The Forest Service administers recreation facilities.

The Mt. Elbert Conduit permits delivery of up to 3,000 gallons per minute of high quality water to the Leadville National Fish Hatchery. Dominant big game species are deer and elk, which migrate into the Twin Lakes area each winter and scatter throughout the surrounding countryside during the summer. Elk range north of the lakes in winter. Big and small game hunting is allowed, in season, in the areas adjacent to Twin Lakes.

Recreation at Twin Lakes and the Mt. Elbert Forebay and Powerplant complex is water-oriented; fishing and boating are the major activities. Facilities consist of a boat ramp, a boat and trailer parking lot, and two car- parking lots with minimum sanitary facilities.

Pueblo Reservoir provides water-oriented recreation in the Arkansas Valley. The Colorado Department of Natural Resources and Colorado State Parks manage facilities constructed by the Bureau of Reclamation including the north and south shore boat ramp, the marina, parking, and the harbor.

A combination warm water fish hatchery and cold water rearing unit, managed and administered by the Colorado Department of Natural Resources, is located downstream from Pueblo Dam. This hatchery provides most of the fingerlings for stocking Pueblo Reservoir and other project reservoirs, streams, and lakes.

For specific information about recreation at any of these sites, click on the name below.

Arkansas River Recreation Management Area
Pueblo Reservoir
Ruedi Reservoir
Turquoise Lake
Twin Lakes

Flood Control

The Fryingpan-Arkansas Project has provided an accumulated $16,814,000 in flood control benefits from 1950 to 1999.

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Last updated: Apr 04, 2013