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Milk River Project
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Milk River Project History (69 KB) (pdf)
General Description| Plan| Development| Benefits

General Description

The Milk River Project in north-central Montana furnishes water for the irrigation of about 121,000 acres of land. Project features are Lake Sherburne; Nelson and Fresno Storage Dams; Dodson, Vandalia, St. Mary, Paradise, and Swift Current Diversion Dams; Dodson Pumping Plant; 200 miles of canals; 219 miles of laterals; and 295 miles of drains. A water supply is furnished to project lands which are divided into the Chinook, Malta, and Glasgow Divisions and the Dodson Pumping Unit. The lands extend about 165 miles along the river from near Havre to a point 6 miles below Nashua, Montana.

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The project provides for storage of water from Swift Current Creek, a tributary of the St. Mary River, in Lake Sherburne behind Lake Sherburne Dam and diversion of St. Mary River water through a 29-mile canal discharging into the North Fork Milk River. The water then flows through Canada for 216 miles before returning to the United States. Milk River water is stored in Fresno Reservoir, located 14 miles west of Havre, and in Nelson Reservoir, 19 miles northeast of Malta. Water is diverted from the Milk River near Chinook and Harlem into private canals on each side of the river for lands in the Chinook Division. All water supply and distribution works have been constructed, and are operated and maintained by the five irrigation districts which constitute the Chinook Division. In the Malta Division, two canals divert water for irrigation of land near Dodson, Wagner, Malta, and Bowdoin. The South Canal conveys water into Nelson Reservoir. From this storage, land is irrigated on the south side of Milk River and on Beaver Creek near Saco and Hinsdale. At Vandalia Diversion Dam, a canal on the south side of Milk River carries water for irrigation of land near Tampico, Glasgow, and Nashua, constituting the Glasgow Division. The Dodson Pumping Plant lifts water from Dodson North Canal to irrigate lands above the gravity system.

Facility Descriptions
Lake Sherburne Dam

Lake Sherburne Dam is a compacted earthfill structure 107 feet in height above its foundation with a crest length of 1,086 feet. The total volume of material in the dam is 242,000 cubic yards. In 1960, the intake tower structure was modified by adding a circumferential overflow spillway crest, and the weir-type overflow spillway at the left abutment of the dam was filled with compacted earth material extending the crest of the dam to the left abutment. Reservoir water surfaces are controlled by operation of the two 4- by 5-foot high-pressure gates, which permit a discharge of 2,100 cubic feet per second at an elevation of 4788.0 ft. At water surface elevations above 4788.0 ft, water flows over the crest of the overflow spillway and the discharge through the outlet works is then comprised of the water flowing over the spillway crest and through the 4- by 5-foot gates. Maximum discharge through the outlet works conduit at an elevation of 4809.2 ft is 4,200 cubic feet per second. A total storage capacity of 68,080 acre-feet is provided in Lake Sherburne. In 1982, the dam embankment was raised to crest elevation 4814.5 using the reinforced earth concept to provide additional surcharge to safely pass the inflow design flood.

Swift Current Dike

The Swift Current Dike is an earth and rock structure with a timber crib core. It is 13 feet high, 4,800 feet long at the crest, and contains 98,000 cubic yards of material.

St. Mary Diversion Dam and Canal

The St. Mary Diversion Works, located on the St. Mary River 0.75 mile downstream from Lower St. Mary Lake, consist of a 6-foot-high concrete weir and sluiceway with a length of 198 feet, and a total volume of 1,200 cubic yards. The St. Mary Canal begins at St. Mary Diversion Dam on the west side of St. Mary River and crosses the river 9.5 miles below the diversion through a two-barrel steel-plate siphon 90 inches in diameter and 3,600 feet in length. Eight miles below the St. Mary crossing a second two-barrel steelplate siphon, 78 inches in diameter and 1,405 feet long, conveys the water across Hall`s Coulee. A series of five large concrete drops at the lower end of the 29-mile canal provide a total fall of 214 feet to the point where the water is discharged into North Fork Milk River. Design capacity of the canal is 850 cubic feet per second.

Fresno Dam

The Fresno Dam, located on the Milk River 14 miles west of Havre, Montana, is a compacted earthfill dam with a structural height of 110 feet and a crest length of 2,070 feet. It contains 2,105,000 cubic yards of material. An overflow-type spillway at the north end of the dam provides for a flow of 51,360 cubic feet per second through the concrete-lined channel. The outlet works discharge a maximum of 2,180 cubic feet per second through two 72-inch steel pipe outlet tubes. A conservation storage of 103,000 acre-feet is impounded in Fresno Reservoir. Provision also is made for flood control benefits.

Paradise Diversion Dam

Paradise Diversion Dam was constructed by the Bureau of Reclamation to replace a rock, log, and brush dam destroyed by floodwaters in June 1965. The dam, located on the Milk River near Chinook, Montana, diverts water for irrigation in the Paradise Valley Irrigation District. The 200-foot-long concrete diversion structure includes a 100-foot ogee spillway section provided with 5-foot-high removable flashboard supports at 5-foot centers along the crest, abutment walls, wingwalls, and cutoff walls, and a sluiceway equipped with a manually operated 5- by 6-foot cast-iron slide gate. Crest elevation of the spillway is 2390.5 ft. Extending from the right abutment of this concrete structure is a compacted earthfill dike, 20 feet wide at the crest, constructed to elevation 2401.5 ft. A cableway with winch-operated cable car, used for maintenance and placement of flashboards when required, spans the spillway section of the dam.

Dodson Diversion Dam and Canals

The Dodson Diversion Dam on Milk River 5 miles West of Dodson, Montana, is a timber crib, weir-type structure with movable crest gates, and an earthfill dike section. The structural height is 26 feet; the crest length is 8,154 feet. The Dodson North Canal, diverting on the north side of the river just above Dodson Dam, has an initial capacity of 200 cubic feet per second and conveys water to Malta Division lands north of Milk River. The Dodson South Canal has a capacity of 500 cubic feet per second, conveys water for irrigation of Malta Division lands south of Milk River, and also conveys water for storage in Nelson Reservoir.

Nelson Dikes and Reservoir

The Nelson Reservoir, located 19 miles northeast of Malta, Montana, provides offstream storage for irrigation of Malta Division lands in the Saco and Hinsdale areas. A series of dikes, with a maximum structural height of 28 feet, crest length of 9,900 feet, and total volume of 233,000 cubic yards, provide for storage of 79,224 acre-feet of water. The reservoir does not have a spillway. Slide gates installed in the Nelson North Canal outlet works permit releases of water to Milk River for use in the Glasgow Division. Slide gates installed in the Nelson South Canal outlet works permit releases of water for irrigation of project lands.

Vandalia Diversion Dam and Canal

The Vandalia Diversion Dam on Milk River, 3 miles west of Vandalia, Montana, is a reinforced concrete slab and buttress weir-type structure with movable crest gates and an auxiliary spillway. The hydraulic height is 27 feet and the total crest length is 2,350 feet. The auxiliary spillway, 1,200 feet in length, is located north of the dam to provide adequate channel for extreme floodflows. The Vandalia Canal diverts on the south side of the river at the dam and conveys water to the land in the Glasgow Division. The canal has a design capacity of 300 cubic feet per second.

The Dodson Pumping Plant, located 2.5 miles northwest of Dodson, Montana, lifts water from the Dodson North Canal 20.5 feet to the Dodson Pump Canal which serves 1,147 acres of land in the vicinity of Dodson. Two impeller pumps of 15 cubic feet per second capacity each, driven by 50-horsepower electric motors, provide 30 cubic feet per second of water.

Operating Agencies

The storage works are operated by the Bureau of Reclamation. The distribution systems are operated by the Malta, Glasgow, and Dodson Irrigation Districts. The systems serving the Chinook Division, are operated by the Fort Belknap, Zurich, Harlem, Paradise Valley, and Alfalfa Valley Irrigation Districts.

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During the 1880`s, settlers built small individual irrigation systems and, in 1890, constructed a community diversion dam in the vicinity of the present Fort Belknap Diversion Dam. Lack of facilities to store the early spring runoff prompted an investigation in 1891 to find a means of supplementing the low summer flow of the river.


The most feasible plan for developing a large irrigation project involved the diversion of St. Mary River into the headwaters of Milk River. Since both rivers flow through Canada, it was necessary to execute a water-right agreement with Canada before the plan could be completed. Increasing irrigation activities in the valley brought urgent requests for development. Investigation of the Milk River Project led to conditional authorization of the project in 1903.


The project was conditionally approved by the Secretary of the Interior on March 14, 1903. The St. Mary Storage Unit was authorized March 25, 1905. Fresno Dam, constructed under the National Industrial Recovery Act, was approved by the President in August 1935, pursuant to the acts of June 25, 1910, and December 5, 1924. The Dodson Pumping Unit was approved by the President on March 17, 1944, under the Water Conservation and Utilization Act of August 11, 1939.


Construction of the St. Mary Storage Unit began on July 27, 1906. A treaty with Great Britain relating to the distribution between Canada and the United States of the waters of the St. Mary and Milk Rivers was signed on January 11, 1909. The Dodson Diversion Dam was completed in January 1910, and the first water delivered for irrigation in 1911. In 1915, the Nelson and Swift Current Dikes, and St. Mary Diversion Dam were completed. In 1917, the Vandalia Diversion Dam was put into operation, Lake Sherburne Dam was completed in 1921, and the Fresno Dam in 1939. The Dodson Pumping Plant was completed in 1946.

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The principal crops produced on the farms in the Milk River Project are alfalfa, native hay, oats, wheat, and barley.

Recreation, Fish & Wildlife

Fresno Reservoir provides swimming, boating, and fishing, in season, for wall-eyed pike and trout. Nelson Reservoir provides excellent fishing, primarily for wall-eyed pike and trout and excellent duck and goose hunting. Practically all of Lake Sherburne is located in Glacier National Park, and fishing is permitted in season. For specific information, please see individual facility pages (link at top under related facilities).

Flood Control

Fresno Reservoir has 32,802 acre-feet allocated to joint use storage which is used for flood control as well as irrigation and other conservation uses and a surcharge capacity of 125,831 acre-feet for a total capacity which may be used for flood control of 158,632 acre-feet. Total accumulated benefits provided by the reservoir since 1950 were about $10.9 million at the end of 1999.

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Last updated: Jul 23, 2012