Water supply of the Dakota sandstone in the Ellendale-Jamestown area, North Dakota, with reference to changes between 1923 and 1938

Abstract

The Dakota sandstone underlies most of North Dakota and South Dakota and considerable parts of nearby States. In most of the area that it occupies it is covered with thick deposits of younger formations, chiefly shale, that confine the water in the sandstone under considerable pressure. Where the topography is favorable, as it is in the Ellendale-Jamestown area in southeastern North Dakota, wells that tap the sandstone flow at the surface. The first well in North Dakota to tap the Dakota sandstone was drilled in 1886 in the city of Ellendale. It was started as an 8- or 10-inch hole and was finished at a depth of 1,087 feet with a 3%-inch casing. It flowed 600 to 700 gallons a minute and had a pressure reported by different persons as being from 115 to 175 pounds to the square inch. The expense of drilling such large and deep wells discouraged their construction for a time. About 1900, however, the jetting method of drilling was introduced^ and during the following two decades hundreds of farm wells 1 inch to 2 inches in diameter were sunk to the sandstone. The decline in artesian head that resulted from the increased draft on the basin was not apparent at first, but by about 1915 the flow of most wells had decreased noticeably and the flow of a few wells in the western part of the area of flow stopped entirely. It is estimated that by 1923 the artesian head at the western boundary of the area of artesian flow had fallen about 330 feet from its original level. In 1916 steps were taken to initiate measures for conserving the artesian water in North Dakota, but it was not until 1921 that the State legislature passed a law providing for the reduction of flow of artesian wells to that which could be used beneficially. The enforcement of the law was placed in the office of the State geologist, and this difficult task was assigned to H. E. Simpson, who directed the work until his death in 1938. Between 1923 and 1928 each artesian well in the Ellendale-Jamestown area was visited and advice was given the owner regarding the flow to which his well should be reduced. Many of the wells were visited again between 1928 and 1935 in order to check on whether the flow had been sufficiently reduced. Through this program much artesian water was conserved and much valuable information was obtained on the discharge from the basin. It is estimated that between 1920 and 1923 the artesian head in the western part of the Ellendale-Jamestown area declined at an annual rate of about 4 feet, whereas in 1938 the rate of decline was only about 0.5 foot a year. Between 1915 and 1923 the part of the area of artesian flow in the Edgeley quadrangle was reduced an average of 16.5 square miles a year as a result of the eastward movement of the western boundary of the area. Between 1923 and 1938, however, the average rate of shrinkage of this part of the area of artesian flow was only about 4.5 square miles a year. The perennial recharge to each row of townships in the area of artesian flow has been estimated to be about 500 gallons a minute. In 1923 the flow from wells in T. 129 N., Rs. 50 to 65 W., was about 1,000 gallons a minute, or twice the estimated recharge. In 1938 the flow from wells in this row of townships was about 520 gallons a minute, or only slightly more than the estimated recharge. Thus it appears that a balance is being approached between the withdrawal of water from the basin and the perennial recharge to it. It is believed that the water withdrawn from the basin in excess of the perennial recharge has been obtained from storage by the compression of .the sandstone and associated beds of shale due to the increased load placed upon them by the decline in artesian pressure. Calculations made on this theory indicate that the coefficient of storage is about 0.001 that is, about 0.001 cubic foot of water is released from each column of sandstone and shale 1 foot square for each foot of decline in artesian head. Additional computations show that the effect of the large decline in artesian pressure in southeastern North Dakota probably has caused only a few feet of lowering of artesian head at distances of more than 100 miles west of the area of artesian flow. The quality of the artesian water is very poor and much of it is unfit for human consumption. Of the 33 analyses included in this report, all show total dissolved solids of more than 2,200 parts per million. Much of the water is salty, and all contains sufficient fluoride to cause mottling of the enamel of the teeth. The temperature of the water from flowing wells ranges from 47° to 69° F.