North Dakota Geological Survey.

Plate XXXIV.

The Valley of Green River, Illustrating a Common Type of Topography in the Lignite Area, and a Valley of a Small Stream, Capable of Irrigation.

tion and cheapest in first cost of plant and erection. It is not, however, so substantial as a direct-acting steam pumping engine and therefore is not so suitable for large permanent works requiring considerable lifts. Where circumstances are suited to its employment, it is one of the best pumps for irrigation. It is adapted to raising water heavily charged with sediment. In construction a centrifugal pump is similar to an outwardflow turbine driven in the reverse direction. Such a pump cannot be put in action until it is filled with water, an operation which is effected through an opening in its outer casing when the pump is below water, or by means of a steam jet when the pump is above water. The efficiency of a centrifugal pump diminishes with the lift, and for lifts exceeding twentyfive or thirty feet a force or plunger-pump produces better results. Centrifugal pumps are generally driven by water, steam or gasoline motors, with which they are connected by belting or shaft and gearing, and they may be erected independently of the motors and at some distance from them. They are also made to gear directly on the motor shaft.

"Many forms of centrifugal pumps are now on the market. They are of varying capacities, from those having two-inch discharge pipes up to those having twenty-four-inch discharge pipes, the largest size being capable of elevating as much as fifteen second-feet, or the same number of acre-feet in a day of twelve hours. Such pumps as these vary in cost according to circumstances, but the larger sizes cost for plant about $100 per second-foot of capacity for moderate lifts, while for fifteen second-foot pumps they require engines capable of developing about five horse power per foot of lift.

"Among the most notable centrifugal pumping plants for irrigation is one for the Vermilion Canal company in Louisiana, consisting of six fifteen-inch pumps, which are claimed to be capable of discharging 130 second-feet of water against a head of twenty feet, and are operated by two engines, each of 250 horse power. Another centrifugal pump working on a farm in southern Arizona and operated by a ten-horse power engine and boiler, has a capacity of two-thirds of a second foot. The operation of this plant calls for the consumption of about one cord of wood per day of twenty-four hours, and is capable of irrigating about three acres per season. A similar pump in the same locality and operated by a gasoline engine of thirty-five horse power will handle about eleven one-half acre-feet in twenty-four hours on a consumption of about ninety-four gallons of gasoline, other centrifugal pumps of small capacity for watering five to ten acres per day and in the course of an irrigation season from fifty to 100 acres, are operated by one man at a cost of about $2.50 per acre irrigated for maintenance and $15 per acre for cost of plant.

"It is proposed to erect an extensive centrifugal pumping plant for the Summit Lake Water company in California, and the estimates of the engineer for a plant capable of irrigating 40,000 acres, including distributing canals and other items, is $81,000, the cost of the pumping plant alone being estimated at about 75 cents per acre, while the cost for operation of and interest on the pumping plant during an irrigation season is estimated

to be about $1 per acre, on the assumption that the depth of irrigation will be one foot and the lift twenty feet. The figures are considerably below those of most gravity systems."*

An interesting description of irrigation by pumping is given by Chandler in his report on water storage on Cache creek, California.**

Conditions here described coincide so nicely with those existing near the headwaters of the tributaries of the Missouri in North Dakota that a portion of the report is reproduced.

"Not being able to rely upon irrigation ditches, many of the farmers about Woodland have resorted to pumping from Cache creek and from wells. Now that their pumping plants are established, most of the operators find them so effective that they would hesitate to abandon them for even an improved system of ditches. In the Woodland district

there are not fewer than twenty places where pumps are now used. Eight of these depend on Cache creek for their supply. As the pumping plants are all below Moore's dam, the supply is generally insufficient after the middle of July. When visited in the latter part of July, 1900, the pumps on the creek could be used only half a day at a time. There was no water flowing in the creek, but long pools have been formed where the water, percolating through the gravel, was forced to the surface. It was from depressions in the pools that the pumping was done, and when the supply was exhausted the pumps were stopped until the pools filled again. In some places earthen dams one foot or two feet high were thrown across the bed to hold the water, and small ditches were dug between the pools above to let more water down. * * * With the exception of the gasoline engine of Mr. S. V. Scarlet, all of the engines in use are steam engines. Straw, brush, wood and coal are used for fuel. The average price paid is 75 cents per load for straw, $4 a cord for wood, $8.50 a ton for coal, and 11 cents per gallon for gasoline."

Throughout the western part of North Dakota the lignite furnishes a cheap and available fuel for irrigation purposes.

The possibility of this plan has already been grasped by farmers at two or three points in the state. Fisher Brothers, on Green river, a small tributary of the Heart, seven miles north of Dickinson, have irrigated for two years, pumping water from the river. The lift is fifteen feet, and a centrifugal pump with a discharge pipe having an inside diameter of eight inches is used. A temporary dam ten inches high and thirty feet long was thrown across the river in 1901 and retained all the water needed to irrigate forty acres. In 1902 an abundance of rain made

*Water Supply and Irrigation Papers, No. 1, p. 48 and 50. **Water Supply and Irrigation Papers, No. 45, p. 23.

irrigation unnecessary. With this pump, which is driven by an ordinary farm engine, 1,500 gallons per minute are easily raised fifteen feet. The cost of the pump delivered was $250. Mr. Fisher estimates that even in a dry season he would have no difficulty in irrigating 200 acres with his present equipment. Two dollars' worth of coal was burned per day, coal costing 50 cents per ton at a neighboring bank. Plate XXXIII illustrates Fisher's centrifugal pump and the Green river from which water is taken. Plate XXXIV shows the Green river valley, which is a type of the valleys of small streams in the lignite area that may easily be irrigated.

Mr. A. F. Riley, on the Little Heart river, near Gladstone, last year irrigated twenty acres by means of a dam thrown across a draw. Next year he proposes to irrigate sixty acres by means of a centrifugal pump. Lignite occurs on his farm outcropping in a four-foot seam, and can be had for the mere labor of mining. Hundreds of localities are as favorably situated as these, and as the population in the western part of the state increases, irrigation will become common.

During the summer of 1903 in co-operation with the Department of Hydrography of the United States Geoleogical Survey, the State Survey proposes to put in the field two parties to follow all of the streams in the lignite area, determine more exactly the outcrops of coal, the extent of land subject to irrigation and the lift necessary to bring the water to them from the streams. When this work is completed an extended report will be made.

Away from the streams wells will very often furnish water for irrigation on a large scale. If a vertical shaft is sunk even to moderate depths coal will commonly be found, but it is attended by so much water that without proper pumping facilities mining is impossible. With a simple surface reservoir into which to pump the water that accumulates in the pit, it may be possible to secure an abundance of water and of coal from the same shaft.