UNDERFLOW IN ARKANSAS VALLEY.
An investigation of the “Underflow in Arkansas Valley” in western Kansas is described in Water Supply and Irrigation Paper 153, published by the United States Geological Survey. Professor Charles S. Slichter, the author, mapped the ground-water level within six to twelve miles of the river channels, and measured the flow of the water by his wellknown electrical method. The measurements were made in private wells and a few sunk for the purpose. The underflow was found to have an average rate of eight feet in twenty-four hours, in the general direction of the valley. The water surface slopes to the east at the rate of seven and a half feet per mile, and towards the river at the rate of two to three feet. The underflow has its origin in the rainfall on the sandhills south of the river and on the bottom lands and plains north of the river. The influence of the floods in the river on the ground-water level does not extend half a mile north or south of the channel. A heavy rain has more influence than a flood. Tt was found that on the sandy bottom lands sixty per cent, of an ordinaryrain reaches the water plane as a permanent contribution. The amount of dissolved solids in the underflow grows less with the depth and with the distance from the river channel. Private pumping plants in the bottom lands will be profitable for irrigation. Professor Slichter states, if the proper kind of power is used. He believes that suctionproducer plants of twentv-horsepower to 100horsepower will prove profitable, using Colorado hard coal or coke.