General Description

The Dalles Project, Western Division is located about 80 miles east of Portland, adjacent to the city of The Dalles, Oregon, on the south side of the Columbia River. Principal features are the Mill Creek Pumping Plant, a booster pumping plant, seven relift pumping plants, three concrete-lined reservoirs, one elevated steel storage tank, five steel regulating tanks, and 46 miles of buried pressure pipe. The division provides water for nearly 6,000 irrigable acres of land.

Plan

No storage for the project's water supply is required as the supply is pumped from the Columbia River about 4 miles downstream from The Dalles Dam, a Corps of Engineers dam. Lands of the Western Division are served by Mill Creek Pumping Plant, an outdoor-type installation with five pumps that have a total maximum capacity of 54.2 cubic feet per second. The 36-inch pretensioned concrete primary discharge line, which serves no turnouts directly, leads to Booster Pumping Plant "A", where five pumps lift 51 cubic feet of water per second against a dynamic head of 419 feet. Seven additional relift pumping plants with a total of 24 pumps raise water to serve project lands that reach an elevation of 1,700.0 feet. The three reinforced concrete-lined surface reservoirs, one elevated steel tank, and five smaller steel regulating tanks provide minimal storage and pressure regulation for the distribution system. Three types of pipe, ranging in size from 36 to 4 inches in diameter, were used in constructing the 46-mile lateral distribution system. Pretensioned concrete cylinder pipe was used in sizes 36 through 14 inches in diameter. Mortar-lined and coated-steel pipe was predominately used in sizes 12 through 4 inches in diameter. Asbestos-cement pipe was used for the Lateral E-6 extension and Lateral F-8A in sizes ranging from 10 to 4 inches in diameter.

The only non-irrigation facilities on the project are the fish screens installed on the pump intakes at the Mill Creek Pumping Plant on the Columbia River. Ten fish screens are provided, two sets for each of the five pump bays. Each screen is 6.25 feet high by 8 feet wide, faced with 16-gage galvanized steel square mesh wire cloth.

To extend the life of the irrigation system and to increase the flexibility of the system to meet peak irrigation demands, the Dalles Irrigation District has replaced several of the pumps with larger capacity units, installed a new steel storage tank, and rehabilitated and modified other facilities. This work was completed in 1999 under the Small Reclamation Projects Act of August 6, 1956 (70 Stat. 1044, Public Law 84-984), as amended.

Operating agency

Operation and maintenance of project facilities was assumed by The Dalles Irrigation District on March 24, 1966.

 Development

The Dalles was settled because river transport in the early years of the 19th century had to be portaged around the Columbia River rapids. A water route southward toward California by way of the Deschutes River Gorge encouraged further growth. The settlement grew into a town because it had become an important transportation hub. Canning and processing fish, fruit, and vegetables constituted the first industry, later augmented by sawmills and an aluminum reduction plant. Some orchards have been irrigated in the project area for many years, using pumped ground water. A somewhat greater acreage is devoted to dryland orchards. The principal crop is sweet cherries.

Investigations

A rapidly falling water table, and the difficulty of successfully operating unirrigated orchards in a region of extremely limited rainfall have been responsible for several investigations and reports on the feasibility of irrigation in the Western Division area. The earliest of these reports outlined a project plan substantially the same as the one finally adopted. A feasibility report, prepared in December 1947, was issued as House Document No. 169, 81st Congress, 1st session, in May 1949, and incorporated in House Document No. 473, 81st Congress, 2nd session, in March 1950. Lack of local interest in developing the project caused it to be held in abeyance until an alarming decline in the water table, that necessitated deepening most of the irrigation wells, led to resumption of investigations by the Bureau of Reclamation in 1958. A feasibility report dated November 1959 resulted from this investigation.

Authorization

Construction of the project was authorized by Congress by the Act of September 13, 1960 (74 Stat. 882, Public Law 86-745). The authorized project purpose is irrigation.

Construction

Construction began late in 1962 and was completed in 1966.

Benefits

All direct and indirect benefits from the project are attributable to irrigation. The project area is well adapted to high quality fruit production, principally cherries. About 75 percent of the area is devoted to orchards; grain, hay, and pasture are the principal crops of the remaining area.

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