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Bostwick Park Project
Photo of Silver Jack Dam and Reservoir
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Bostwick Park Project History - 37 KB (pdf)
General Description| Plan| Development| Benefits


General Description

The Bostwick Park Project is in west-central Colorado near the city of Montrose. The project develops flows of Cimarron Creek, a tributary of the Gunnison River, for irrigation and for benefits to sport fishing and recreation. A full and supplemental supply of irrigation water is available for 6,100 acres of land. Recreation opportunities and important fishery benefits are provided at Silver Jack Reservoir.

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Water storage is provided by Silver Jack Dam and Reservoir, constructed on Cimarron Creek. Project water is released from the reservoir to Cimarron Creek. The releases, along with usable natural flows, are diverted from the creek into the existing Cimarron Canal 2.5 miles below the dam, and conveyed 23 miles to the vicinity of the project land. Some water is released from the canal and used on lands in the Cimarron area. Most of the water is conveyed to the end of the canal at Cerro Summit and then delivered to the Hairpin and Vernal Mesa Ditches. The project-constructed Bostwick Lateral diverts water from the Vernal Mesa Ditch and conveys it across Bostwick Park through an 18-inch siphon to lands above the West Vernal Mesa Lateral.

Facility Descriptions

Silver Jack Dam

Silver Jack Dam is located on Cimarron Creek about 20 miles above the junction with the Gunnison River. The rolled-earthfill dam contains 1,278,140 cubic yards of material and has a structural height of 173 feet. Its crest is 1,050 feet long and 30 feet wide. The outlet works to Cimarron Creek in the right abutment has a capacity of 280 cubic feet per second with the reservoir at the normal water surface elevation of 8926.0 feet and a capacity of 160 cubic feet per second at the minimum water surface elevation of 8840.0 feet. The spillway on the right abutment is an uncontrolled ogee section with a capacity of 6,220 cubic feet per second at maximum water surface elevation. The reservoir has a total capacity of 13,520 acre-feet, including 12,820 acre-feet of active capacity and 700 acre-feet of inactive capacity. When filled to its normal water surface elevation, the reservoir has a surface area of 293 acres.

Bostwick Lateral and Drains

The 3.6-mile Bostwick Lateral was constructed to deliver water to full service lands above the West Vernal Mesa Lateral. Repair, extension, and some new construction of about 7.2 miles of drains were completed by the water users.

Operating Agencies

Project irrigation facilities were turned over to the Bostwick Park Water Conservancy District for operation and maintenance on January 1, 1976.

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The Bostwick Park area was settled in the early 1880`s, followed by a second influx at the time of irrigation development in 1910. By 1930, the population had reached a peak of 75 to 80 families, but in 1960 decreased to about 40 families because of the trend toward larger farm units, use of modern labor-saving farm equipment, and drought conditions.


The Bureau of Reclamation first reported on the Bostwick Park Project in a 1951 reconnaissance report on the Gunnison River Project. The plan presented in the 1961 feasibility study, upon which authorization was based, was essentially the same as the 1951 plan.


The project was authorized as a participating project of the Colorado River Storage Project by Public Law 88-568, September 2, 1964 (78 Stat. 852). The primary purposes of the project are agriculture, recreation, and fish and wildlife.


Construction began at Silver Jack Dam late in 1966 and was completed in 1971. Silver Jack Reservoir was filled on June 10, 1971, and project water was available to supplemental service lands from existing ditches on a water rental basis during the 1971, 1972, and 1973 irrigation seasons. A negative declaration of environmental impact was filed July 21, 1972, for drainage rehabilitation and for replacement of the Vernal Mesa conduit. Construction of these facilities was completed during fiscal year 1974.

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The project furnishes a dependable late-season supply of irrigation water. Non-project supplies are generally abundant until the latter part of the irrigation season, but then fall off resulting in serious curtailment of crop yields. Project water from Cimarron Creek, and in small part from tributaries of Cedar Creek, is used as a full irrigation supply for lands not previously irrigated and as a supplemental supply for lands inadequately served.

Raising beef cattle and sheep are the major enterprises in the project area. Irrigated lands are used chiefly for the production of alfalfa, grass hay pasture, and small grains for livestock feed.


The U.S. Forest Service developed recreation facilities by the Forest Service under a cooperative arrangement with the Bureau of Reclamation. Facilities include access roads, campgrounds, a boat dock, trails, fences, landscaping, and an administration site. There were 84,500 visitor days to the reservoir area in 1996. For specific information about recreational opportunities at Silver Jack Reservoir click on the name below.

Flood Control

Although there is no specific reservoir capacity assigned for flood control, the Bostwick Park Project has provided an accumulated $34,000 in flood control benefits from 1950 to 1999.

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Last updated: Dec 22, 2009