1

would be an outdoor-type installation, but the high-head unit would be housed in a structural steel frame with metal siding. The plan for the plant is shown in the accompanying drawing.

Automatic float controls connected to the main regulating reservoir would operate the main pumping plant.

The main pumps would be attached to a 24-inch diameter 7,800foot long coal-tar-enameled-steel discharge line. Five laterals and two farm turnouts would take off from the discharge line before it reaches the regulating reservoir. Distribution system

The distribution system for this unit would consist of a steel and asbestos-cement lateral system, two regulating reservoirs, and a relift pumping plant.

Lateral system.-The arable area is made up of numerous parcels of irrigable land lying between elevation 1,000 and 1,400. This makes a closed pipe system desirable.

The system planned for this unit would be a buried pipe system providing a minimum sprinkler pressure of 25 pounds per square inch at the high point of the farm unit. The system is designed to deliver, on a continuous flow basis, 1 cubic foot per second for each 62 irrigable acres or about 7.3 gallons per minute per acre and will deliver about 26 percent of the estimated seasonal requirement of 3.83 acre-feet per acre in a 31-day period. It is laid out to provide 1 turnout for each 20-acre farm unit, a total of 89 turnouts.

The pipe sizes range from 4 to 14 inches in diameter. Pipe 10 inches in diameter and larger would be coal-tar-enameled steel with sleeve-type couplings. Pipe from 4 to 8 inches in diameter would be of asbestos-cement with cast-iron fittings.

The farm turnouts would be similar to those on the East unit and other units with sprinkler systems. They would include 4-inch gate valves and 4-inch propeller-type water meters.

The lateral system layout is shown on the accompanying drawing:

Relift pumping plant.-An outdoor-type relist pumping plant would be required to irrigate a 455-acre bench slightly higher than the remainder of the project lands. The plant would contain 2 vertical turbine-type pump and motor units and would have a maximum capacity of 3,400 gallons per minute against a dynamic head of about 100 feet. Float controls in the regulating reservoir would operate the relift pump plant.

Regulating reservoirs.-A 570,000-gallon concrete-lined main regulating reservoir would be constructed on the high edge of the project and would contain float-operated controls to regulate the pump motors of the main plant. It would not have an overflow spillway.

A similar 232,000-gallon regulating reservoir would be used in conjunction with the relift pumping plant.

CONSTRUCTION AND OPERATION

The Brays Landing unit, like all of the other units in the Division, would be constructed under the supervision of the Bureau of Reclamation. It will be necessary to form an irrigation district to contract with the Government for repayment of the construction charges and to operate and maintain the facilities,

Construction schedule

Construction of the Brays Landing unit would require about 24 years. Most of the first year would be taken up by preconstruction activities and preparation of designs and specifications. Construction work would follow the order shown on the control schedule (form PF-2) at the end of the chapter. The system would be completed and tested in time for the irrigation season of the third year. Operation and maintenance

Operation and maintenance of the Brays Landing unit would be carried out by the water users. An estimate of the cost of operation and maintenance has been prepared by adding the cost of the required operating staff to an estimate of the cost of operation and maintenance of specific items.

PROJECT COSTS

Estimated costs for the Brays Landing unit consist of the costs of constructing the irrigation system, capitalized operating costs, and the annual expense of operating the system. Construction costs

The estimate of the construction cost of the Brays Landing system includes the cost of constructing the irrigation works, past investigations, the facilities required during construction, and the permanent installations required to operate the unit. This construction cost totals an estimated $1,642,000 at the July 1955 price level, as shown on the official estimate at the end of this chapter (form PF-1). Capitalized operating costs

An estimate of capitalized operating costs for the Brays Landing unit amounts to $116,000. Annual operating costs

The annual expenses of operating and maintaining the irrigation system include the cost of operation, maintenance, and replacements and the cost of electric power for the pumping plants.

Operation, maintenance, and replacement. The cost of operating and maintaining the Brays Landing unit system has been estimated by developing a staff for its operation and adding to the labor costs an estimate of the several costs that would be incurred by a project

of this type.

The cost of major replacements that will be required in the pumping units and electrical facilities was estimated separately on a straightline depreciation basis. Maintenance work that would be done by the operating force was estimated for each major item. The following tabulation is a summary of the estimate. Personnel

Maintenance items.

$4, 412 Irrigation meters.

$734 Discharge line.

1,053 Reservoirs..

125 Relift plant.

41 Substation transmission lines.

1, 236 Lateral system.---

1, 223 Total, current cost basis..

21, 032 Rounded..

21, 000 Pumping power.-Power-cost estimates for the Brays Landing unit, and for all units in the division, are predicated on the Greater Wenatchee division receiving a 1-mill pumping rate from the Federal power system. Because the Brays Landing unit is not located near a Bonneville transmission line, power for the unit would be obtained through wheeling arrangements with Chelan County Public Utility District and the Puget Sound Power & Light Co.

The estimated cost of the estimated 6,400,000 kilowatt-hours of pumping energy is $6,900 annually, or 1.08 mills per kilowatt-hour. Summary of annual operating costs

When the annual operation, maintenance, and replacements costs of $21,000 are reduced to a long-range level by the Engineering News Record Index of July 1955, the result is $13,500.

The total of the above cost and the annual power costs is $20,400 as shown below.

The Howard Flat unit lies on a large, relatively flat terrace about 600 feet above the Columbia River and near the town of Chelan, Washington. The plan for developing this unit would provide an adequate supply of irrigation water for 866 acres of irrigable land.

Several attempts have been made to bring irrigation to the Howard Flat, including the formation of an irrigation district. This organization, the Howard Flat Irrigation District, although inactive for some time, would probably be the nucleus for a water users' organization to contract with the Government for repayment of construction costs.

PLAN OF DEVELOPMENT

Water for the Howard Flat unit would be pumped from the Columbia River through a lift of 663 feet to a regulating reservoir located at the end of the discharge line. It would then be conveyed to the unit lands through a low-head pipe distribution system. Distribution would be by the gravity (furrow) method. Pumping power for the unit would be obtained from the Federal power system through a wheeling arrangement with the Chelan County Public Utility District. Howard Flat pumping plant

The Howard Flat pumping plant would be located on the right bank of the Columbia River in the Sw-y of section 26, T. 28 N., R. 23 E., Willamette meridian. It would have a maximum capacity of 17 cubic feet per second (7,600 gallons per minute) against a total dynamic head of 686 feet. Two deep-well turbine-type pumps of 8.5 cubic feet per second capacity each, outdoor type, would be installed in a wet-well-type structure connected to the river by a 36-inch diameter conduit. The outer end of the intake conduit would be equipped with fish screens and trashracks. Details of the proposed plant are shown on the accompanying drawing.

Operation of the plant would be regulated by float-operated automatic controls in a regulating reservoir at the end of the discharge line. The discharge line from the pumping plant would be 30-inch diameter steel pipe connected to the pumps by a fabricated steel wye manifold. For most economical construction, the first 1,900 feet of the 3,100-foot long discharge line would be constructed above ground on concrete piers. The remaining 1,200 feet would be buried. Distribution system

The Howard Flat unit distribution system is designed for furrow irrigation. It includes a regulating reservoir, a short length of concrete-lined canal, and a low-head concrete pipe lateral system.

Regulating reservoir.—The regulating reservoir for the unit would be an elongated canal section at the end of the discharge line. It would have a capacity of 450,000 gallons and a water depth of 5 feet. A float well at the upstream end of the reservoir would contain automatic float controls to operate the pumping plant motors. The outlet structure for the reservoir would contain a floating radial gate which could be regulated to supply a constant quantity of water while the reservoir depth fluctuates through a range of 5 feet.

Main canal.—This canal would begin at the equalizing reservoir and extend for 3,200 feet around the northern end of the project area. It would be concrete-lined with a water depth of 1% feet and a maximum bottom width of 3 feet. A wasteway at the end of the canal would spill excess water into a large natural depression.

Lateral system. The lateral system for the unit is designed to serve each ownership or a maximum-size tract of 40 acres. Laterals would be constructed of low-head concrete irrigation pipe. A small amount

A of class 50 asbestos-cement is used where the head in the pipeline exceeds 15 feet. The system also includes a 24-inch diameter steel siphon across a low area. The system is designed to deliver 1 cubic foot of water per second for 54 irrigable acres or 8.2 gallons per minute per acre, and will provide approximately 26 percent of the estimated seasonal requirement of 4.32 acre-feet per acre in a 31-day period.

All the lateral-system pipe would be buried and would deliver water to the high point of each farm unit. Concrete weir boxes would be installed along the laterals to serve as standpipes to prevent the head in the lines from exceeding 15 feet.

The farm turnouts would be equipped with a combination meter head and shutoff valve that permits regulation of flows to the farm as well as measurement of the water.

The accompanying drawing illustrates the plan of the lateral system.