General

The North Loup Division of the Pick-Sloan Missouri Basin Program is located within the Loup River drainage basin in central Nebraska. Diversion facilities are on the Calamus and North Loup Rivers. The plan provides direct surface water service to 53,000 acres of land. Operation of the division provides a sustained ground-water supply for the development of an additional 17,000 acres by private investment. Of the 70,000 acres benefiting from project development, 43,500 are considered to be nonirrigated and 26,500 are considered to be irrigated. In 1992 the total irrigable land was 33,970 acres. The Twin Loups Reclamation District and the Twin Loups Irrigation District will benefit from and pay for the irrigation facilities. In addition to irrigation, the division includes recreation and fish and wildlife benefits.

History

Early History

The first settlers started arriving in the Platte River Valley by way of the Oregon Trail in 1832. However, the Loup River area remained unsettled until the late 1860`s From the beginning, the farmers were plagued with invasions of grasshoppers and other pests, but the greatest deterrents to stability in the agricultural economy were insufficient rainfall and recurring droughts. There were attempts to irrigate, with individuals devising and operating simple methods to bring water to the land.

Several cooperative and district-type irrigation plans were conceived, and a few irrigation systems were built.

Some irrigation districts were eventually organized; the largest was the North Loup River Public Power and Irrigation District. Other irrigation development is generally limited to water being pumped from the river to irrigate adjacent lands. The Twin Loups Reclamation District, organized in 1954, and the Twin Loups Irrigation District, organized in 1958, were formed as legal entities of the State of Nebraska to operate the North Loup Division.

Investigations

Investigations in the area were conducted by private engineering firms beginning in 1933. The Bureau of Reclamation made its first study in 1943 and the resulting recommendations for irrigation development in the Loup Valley were included in Senate Document 191. This plan received basic congressional approval and authorization by the Flood Control Acts of 1944 and 1946.

A more intensive investigation was undertaken late in 1944 and a preliminary report was completed for the Lower Plate River Basin in 1951. Plans for a North Loup Division, similar to those in Senate Document 191, were included in this broad basin plan.

Detailed studies in 1954 resulted in publication of a feasibility report that was included in House Document No. 491, 87th Congress, 2d session, dated 1962.

Authorization

The division was authorized by the Reclamation Project Authorization Act of 1972, Public Law 92-514, on October 20, 1972. The Public Works for Water and Power Development and Energy Research Appropriation Act of 1976 authorized and provided funds for a construction start.

Construction

Construction began on June 4, 1976, with execution of the first contract in connection with improvement of the county road for access to Calamus Dam site. This road improvement was completed June 16, 1977.

Operating Agencies

It is planned that the irrigation district will, by contract, vest all operation, maintenance, and replacement responsibility in the reclamation district. Fish and wildlife facilities and lands will be administered by the State of Nebraska.

Irrigation

The North Loup Division will provide a water supply to the area that can be served economically by gravity and private farm pumps.

Recreation and Fish and Wildlife

The division will provide increased recreation opportunities, particularly those associated with water sports. Fish and wildlife resources will be benefited by the water development project. Principal benefits will be to fishing and hunting.

Plan

Principal features of the division include Calamus Dam and Reservoir (now Virginia Smith Dam and Calamus Lake), Kent Diversion Dam, Davis Creek Dam and Reservoir, five principal canals, one major and several small pumping plants, and laterals. Provisions for necessary surface and subsurface drainage systems also are included. Recreation enhancement facilities are included; however, no features for fish and wildlife enhancement have been incorporated for the present.

The lengths and capacities of the canals and laterals, and the number of units, capacities, heads, and horsepower requirements for the pumping plants are as authorized and based on feasibility designs contained in House Document No. 491, the February 1971 re-evaluation statement, and the April 1978 special report. As preconstruction planning studies and detailed design data collection progresses, changes are expected in canal and lateral lengths and capacities, and in pumping plant requirements for the various features.

Virginia Smith Dam and Calamus Lake

Virginia Smith Dam is located across the Calamus River about 5.5 miles northwest of Burwell, Nebraska. The dam is constructed of rolled earthfill with a maximum height above streambed of 95 feet and a crest length of 7,295 feet. The elevation of the crest is 2,259.0 feet. The embankment volume is about 6 million cubic yards.

The upstream slope of the dam will be protected by a layer of soil cement. An impervious blanket 10 feet thick will extend upstream 500 feet from the upstream toe. This, together with an earthfill cutoff trench to a depth of 30 feet below the ground surface, will reduce percolation under the dam. Water percolating to the downstream toe of the dam will be intercepted and drained by inspection and drainage wells, and a 5-foot-thick sand and gravel drain will be located under the downstream toe. The crest of the dam will be 30 feet wide.

The river outlet works will have a capacity to discharge 2,460 cubic feet per second. It will consist of a trashrack, inlet transition, and a 10-foot-diameter steel-lined conduit to a 6.5 by 10-foot outlet gate installed in a gate chamber 30 feet upstream from the dam axis. Downstream of the gate chamber will be a 9- foot-diameter steel pipe encased in concrete terminating in a wye branch, with each branch containing two 5.5-foot, high-pressure gates in control houses.

One branch of the wye will carry water to the canal outlet works. This branch can discharge 720 cubic feet per second into the Mirdan Canal when the reservoir water surface is at the bottom of the conservation capacity, elevation 2213.3. After passing through high-pressure gates, the water will go through a wave suppressor and then a 20-foot-wide Parshall flume. Beyond the flume, the water will enter the canal at water surface elevation 2206.5. The need for a fish screen in the canal is being studied.

The other branch of the wye will control the water required for returns to the Calamus River. The branch to the river also will be used to discharge part of the inflow design flood. All natural flows of the Calamus River during July and August, and those of September when storage water is available to meet division needs, will be returned to the river. Beyond the high-pressure gates will be a stilling basin. The releases will be measured at a gaging station located about 2 miles downstream from the damsite.

The spillway will be a morning-glory type with a crest 30 feet in diameter located in the upstream slope of the dam at elevation 2244.0. Spilled water will drop 44 feet into a 10-foot-diameter conduit extending through the dam. At the outlet end of the conduit, a stilling basin will dissipate the energy of the water before it enters the Calamus River channel below the dam. With the use of 27,400 acre-feet of surcharge, the maximum discharge through the spillway will be 2,760 cubic feet per second under conditions of the inflow design flood. In addition, the river outlet will be used to pass part of the inflow design flood.

Kent Diversion Dam

Kent Diversion Dam will be located in Loup County on the North Loup River about 8 miles upstream from its confluence with the Calamus River. It will be a concrete ogee structure with a height above streambed of 9 feet. Its length will be 1,000 feet and the canal headworks capacity will be 350 cubic feet per second. The structure will be used to desilt and divert water from the North Loup River into the Kent Canal.

Davis Creek Dam

Davis Creek Dam will be located on a tributary to Davis Creek about 5.5 miles south of North Loup. The dam and blankets near each end will be of rolled earth with a maximum height of the embankment above streambed of III feet, and a length of 3,000 feet at crest elevation 2093.

The upstream slope of the dam will be protected by either a 3- foot layer of rock riprap on an 18-inch gravel bedding, or a layer of soil cement. The downstream slope will be covered with 12 inches of topsoil and seeded to grass. Drainage will be accommodated by a sand and gravel blanket with a tile toe drain, located in the downstream toe of the dam. The embankment will have a volume of 3,350,000 cubic yards.

A single canal outlet will have the capacity to discharge 400 cubic feet per second with water in the reservoir at the bottom of the conservation capacity, elevation 2003.0. It will consist of a trashrack, inlet transition, and a 6-foot-diameter conduit to a 5-foot-square, high-pressure control gate installed in a gate chamber 50 feet upstream from the crest of the dam. Below the control gate will be a 72-inch-diameter steel pipe in a 10-foot 4-inch concrete conduit. The steel pipe will terminate in a wye with each branch containing a 3.5-foot-square, high- pressure regulating gate. Water from the outlet will pass into a stilling basin to dissipate energy before entering the Fullerton Canal at water surface elevation 1980.0.

The spillway will he a rectangular drop inlet covered by a trashrack with a crest elevation of 2076 ft. A concrete conduit 4.5 feet in diameter will extend from the bottom of the drop inlet to a stilling basin beyond the downstream toe of the dam. This basin will dissipate the energy in the water before it discharges into an excavate( channel that will join the Fullerton Canal.

Pumping Plant

One large and one small pumping plant will be constructed.

Geranium Pumping Plant will be located less than a mile west of Mirdan Canal, southwest of Elyria, Nebraska. This pumping plant will permit irrigation of 11,746 acres that are at too high an elevation to be irrigated by gravity service. The plant will be capable of lifting 200 cubic feet per second at a dynamic head of 130 feet. The average annual power requirement for this plant is estimated at about 4 million kilowatt-hours, with a peak demand of 3,460 kilowatts. Power from the PSMBP will serve the plant.

The smaller pumping plant will be located on Geranium Lateral, and will have a capacity of 13 cubic feet per second, with a dynamic head of 72 feet. Power from local utilities will serve the plant.

Canals and Laterals

Six canals will serve the lands of the division. They are the Mirdan, Kent, Geranium, Scotia, Fullerton, and Elba Canals, and range in capacity from 12 to 720 cubic feet per second and in length from 4 to 49 miles. Concrete lining or compacted earth lining will be required for some reaches of the canals. The lateral system consists of 146 miles of laterals with capacities ranging from 4 to 80 cubic feet per second.

Overview

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Other

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