Abstracts Earth and Environmental Sciences

Ground water of the Uncompahgre Valley Montrose County, Colorado

by Ted William Craig

"Data from water quality tests of 50 wells and from general well information of 309 wells registered with the Colorado Division of Water Resources are presented for the area of Montrose County, Colorado, drained by the Uncompahgre River. This information, along with other pertinent information such as water laws and costs, is evaluated to determine the feasibility of increasing the use of ground water in the area. The drainage basin of the Uncompahgre River within the Montrose area bas three main geologic structures: the Uncompahgre uplift, the Montrose syncline, and the Gunnison uplift. All formations exposed in the area are Mesozoic in age. The most important of them are the Morrison and Dakota formations and the Mancos shale. The Morrison and Dakota are the bedrock aquifers of the area. Overlying these consolidated materials are a series of Quaternary gravels that comprise the remainder of the groundwater sources. The quality of the water from the 50 wells, chosen by random from a system of one-ninth township divisions, was fair to poor. High concentrations of dissolved solids, sulfate, fluoride, and iron tend to be the worst quality problems. Groundwater quality was usually suitable for most agricultural and domestic uses if the high mineral content and its resultant tastes, smells, and stains are not objectionable for a particular use. Limited quantities available tend to limit groundwater use for purposes such as irrigation. Stock watering is the use for which the ground water of the area seems to be best suited. Stock prefer the ground water over surface water. If higher yields could be established, the wells would also be suitable for irrigation of most area crops" – Abstract, page ii.