In South Dakota, parts of Iowa, and in many other parts of the humid States, artesian wells lifting water to the surface in great volume are quite common. They are utilized for irrigation of fruits and crops, but the gain is not as great as is usually suspected. It is not often that the position of the well is favorable for irrigating as large an area as the volume of water would indicate. If water is raised a few feet to a reservoir on the highest ground in the near vicinity it can be utilized at time of greatest need over a large area by troughs or pipes. But it seldom happens that an artesian well can be made to run the water into large reservoirs high enough to be used over as much surface as the water will cover in a humid State. But in the relatively few localities where artesian wells can be obtained at the highest points they will prove very valuable if the surplus water can be stored in late winter and spring for use in the dry season.
In relatively flat countries with some undulation artesian water is distributed to good advantage when the pressure of water will lift it to a height of fifteen feet or more. In the Libyan desert of north Africa are now found hundreds of such wells furnishing water for immense plantations of date-palms and other tropical fruits. But where water comes within twenty feet of the surface and the supply is plentiful, the modern gasoline pumps raise and carry the water to elevated reservoirs at a cost so moderate that it is trifling when compared with the usual cost of water in the arid districts. Indeed, the reservoir system has been the main one used in ancient and modern times. In the arid regions the water of the wet season is stored in immense ponds or lakes for use in the dry period, usually in mountains, or by damming mountain streams. In the dry season this stored water is used on large tracts during a long period. In the humid States the dry period is short. Hence our friends from the arid States need not make sport of the smaller ponds filled by pumping from stream-beds or wells.