River About Yellowtail Recreation Afterbay Yellowtail Dam and Afterbay Dam 313 Bighorn Bighorn Lake is 71 miles long and is a Yellowtail Dam & Visitor Center Reservoir Dam deep blue-water fishery created by Ok-A-Beh Type...... Concrete arch Yellowtail Dam. Over 190 miles of Fort Smith (feet) Park Height above foundation ...... 525 shoreline showcase colorful geology and HQ Crest length (feet)...... 1,480 an area rich in history and tradition. Much ake Crest width (feet)...... 22 of the reservoir’s length is within the L

Crest elevation (feet)...... 3,660 n Bighorn Canyon where wildlife is r o Base thickness at center (feet)...... about 145 h abundant and the scenery is spectacular. ig Volume (cubic yards)...... 1,546,000 B Spillway: A32 foot diameter tunnel The Afterbay Lake belowReservation the reservoir Boundary is in the left abutment controlled by a good spot for trout fishing. Flows in two radial gates 25 feet wide by Bighorn River below the Afterbay Dam 64.4 feet high. The spillway are clear and cold. This has allowed the capacity in cubic feet per river to become a world class trout fishing BIGHORN CANYON Crow second (cfs) at elevation 3,660...... 92,000 area. NATIONAL River Outlet: Two 84 inch diameter is located on the RECREATION AREA Indian Yellowtail Dam conduits controlled by ring-follower The Bighorn Canyon National Bighorn River at the mouth of Bighorn gates with a capacity (in cfs) of...... 5,000 Recreation Area (NRA) Reservation Canyon about 43 air miles from Billings, Power outlets: Four 12 foot diameter surrounds the reservoir and Montana. When full, the reservoir penstocks through the dam. afterbay and is managed by Barry’s Landing extends 71 miles south into Wyoming. the National Park Service. North The dam and reservoir provide multiple Reservoir (Bighorn Lake) The NRA was dedicated in Capacity (acre-feet at elevation 3,657)...... 1,375,000 benefits to the American public including October 1968 three years 0 5 Miles 10 Area (acres at elevation 3,657)...... 17,300 power generation, flood control, irrigation, after the dam was completed. Devil Canyon Overlook municipal and industrial water, fish and Length (river miles at elevation 3,657)...... 71 Offices and Visitor Centers Water surface elevations (in feet): are in Fort Smith, Montana, MONTANA wildlife benefits and recreation. The Joint-use storage...... 3,614 to 3,640 and Lovell, Wyoming. WYOMING facility is operated by: Flood control storage...... 3,640 to 3,657 Bureau of Reclamation Horseshoe Bend Additional recreation Symbol Key Montana Area Office Powerplant information is available at: Four vertical shaft generators P.O. Box 30137 Wheelchair accessible connected to Francis type turbines. Billings, MT 59107-0137 http://www.rec.gov or (406) 247-7295 Total nameplate capacity (kilowatts)...... 250,000 http://www.nps.gov/bica. Ranger station Capacity each generator (kilowatts)...... 62,500 Capacity each turbine (horsepower)...... 87,500 Boat Ramp 37 Afterbay Dam: Marina Type: Composite concrete gravity with embankment wings Shoshone River Height above foundation (feet)...... about 40 Swimming area - lifeguards Crest length (feet)...... 1,360 Lovell Picnic area Crest width (in feet for embankment section)...... 28 14A Crest elevation (feet)...... 3,197 Campground Outlet works: Five radial gates and three Reservoir elevation, river flows and boat sluice gates control flows to the river launch information is available at Snack Bar with a total capacity (in cfs)...... 24,500 http://www.usbr.gov/gp by clicking on the Two sluce gates control flow to the links for recreation or lakes and reservoirs BIAcanal with a capacity (cfs)...... 750 on the left side of the page.

River publication last revised 4/14/2008

Bighorn The Yellowtail Unit Electricity Water of the Pick-Sloan Missouri Yellowtail Powerplant is located at the Basin Program downstream toe of Yellowtail Dam and covers Water has many uses at the Yellowtail Unit. nearly all the width of the river. Four Each use provides benefits to the American public and is consistent with state law, the Most of the water and power facilities in the generating units are operated independantly to provide power for homes and businesses. terms and conditions of the Yellowstone River Missouri River Basin were constructed under Compact and contemporary environmental the Pick-Sloan Missouri Basin Program (Pick- law. Sloan), authorized by the Flood Control Act of 1944. Pick-Sloan is one of the most extensive Hydropower is perhaps the most important plans ever developed for management of an use of water at Yellowtail. Low cost electricity entire river basin. is provided to the region and the water is available for other uses after it flows through To maintain safety and reliability, Reclamation Pick-Sloan brought together a flood control the turbines and returns to the Bighorn River. constantly evaluates facility needs. Scheduled and navigation plan developed by the Army maintenance often requires a unit to be taken Corps of Engineers and an irrigation and Flood control is another major benefit from apart. Coordinating such work with users and hydroelectric plan prepared by the Bureau of the dam. Yellowtail is operated with other other powerplants is essential for meeting Reclamation. Together they became a facilities in the Bighorn and greater Missouri demand for power. comprehensive approach to multiple-purpose River basins to reduce damage caused by benefits in the basin. Today benefits include flooding. Yellowtail is credited with over $113 Shown in the photo above is one of Yellowtail irrigation, hydroelectric power, flood control, million in savings from 1965 through 2007. Powerplant’s four turbine runners which has navigation, recreation, sediment abatement, been refurbished and is ready to be Fish and wildlife have benefitted from the fish and wildlife enhancement and municipal reinstalled. At left is a Reclamation employee development of special management areas and industrial water. directing the lifting of one of the generator around the reservoir that preserve habitat for rotors for maintenance. waterfowl, upland birds and other animals. The dam transformed the Bighorn River between Fort Smith and the Yellowstone River into an internationally recognized blue-ribbon The Afterbay Dam trout fishery. The reservoir is home to brown and rainbow trout, walleye, sauger and other Hydropower is uniquely capable of quickly species. The Afterbay is also a trout fishery. generating electricity when demand rises and conserving energy when it is not needed. Recreation is one of the most visible uses This “peaking power” ability is enhanced when of water for visitors to Yellowtail. The Bighorn the widely varying flows do not adversely Canyon National Recreation Area was impact those who live downstream. Yellowtail created to provide recreation opportunities provides peaking power for a part of each day around the reservoir for the American public. and the Afterbay Dam continuously regulates The prime contract for construction of the dam the flows. Municipal and Industrial water use is was awarded in April 1961, and the last one of the authorized purposes of the The widely varying releases from the bucket of concrete was placed in the dam Yellowtail’s annual power generation over the Yellowtail Unit as with many Pick-Sloan powerplant are regulated by the Yellowtail during October 1965. The construction of the last 10 years has averaged nearly a million facilities. Afterbay Dam located 2.2 miles downstream. powerplant began with the dam and was kilowatt-hours. That is enough electrical The afterbay, with a capacity of 3140 acre- Irrigation water is released into the completed in December 1967 when the last unit energy to supply about 80,000 homes. The feet, minimizes downstream fluctuations in the Bighorn Canal to satisfy senior water rights was placed in service. Yellowtail Afterbay Dam power is marketed to utilities and electric Bighorn River by temporarily storing peak was started in April 1964 and was completed in cooperatives throughout the west by the for the Crow Indian Irrigation Project and discharges from the powerplant. November 1966. Western Area Power Administration. other irrigators.