The hardness of available shallow ground water in Otero County and in the southern part of Crowley County generally exceeds 1,000 parts per million, and the water requires treatment for most uses. To obtain a supply of softer water, wells have been drilled into the Dakota Sandstone and the Cheyenne Sandstone Member of the Purgatoire Formation, both Early Cretaceous in age. These aquifers underlie most of ,the area at depths from 0 to 2,000 feet and have a general regional dip northward into the Denver Basin. More than 50 wells have been drilled into the aquifers in this area to obtain water for stock, domestic, and industrial purposes and for public supply. The aquifers are recharged in areas where they crop out or are overlain by sand, principally to the south and west of Otero County. Because water in the aquifers is generally under pressure, it rises above the top of the aquifer in wells penetrating it; at least 20 wells in the area flow. Yields from wells tapping the aquifers range from 4 to 75 gpm (gallons per minute). Flows as great as 50 gpm have been obtained.
Water in the aquifers is commonly soft and of good chemical quality. There appears to be little difference in quality of water from the two aquifers. Most residents and drillers know that soft water can be obtained from wells throughout most of the area described in this report, but many are not aware of certain factors related to the development of this water. This report should be of value in further developing the sources of soft water by showing: (a) The approximate depth of a well needed to tap these supplies, (b) the range in yields that may be expected, (c) the range in chemical quality that may be expected, (d) the depth to which water will rise in wells, and (e) information on the factors affecting the durability of the supply.
Additional Publication Details
USGS Numbered Series
Water in the Dakota and Purgatoire Formations in Otero County and the southern part of Crowley County, Colorado