Selected climatic characteristics of the southeastern Uinta Basin, Utah and Colorado

Abstract

The southeastern Uinta Basin in Utah and Colorado contains large reserves of oil shale, the mining of which could affect the area 's water resources. Climatic characteristics of the area, which were evaluated as one phase of a comprehensive hydrologic study, are presented to help provide the means of evaluating the impact of mining on the area 's water resources. Data for precipitation , air temperature, and evaporation obtained by the U.S. Geological Survey from October 1974 to September 1978, and similar short-term data obtained by other Federal agencies at sites in and near the study area, were tabulated and adjusted to a 1941-70 base period. For all sites with incomplete records for 1941-70, the data were adjusted by relating them to concurrent data collected at one or more long-term National Oceanic and Atmospheric Administration sites. Maps were prepared showing areal variance for normal annual precipitation, normal annual air temperature, and normal annual pan evaporation.. The normal annual precipitation ranges from less than 8 inches for altitudes under 5,000 feet to more than 20 inches above 9,000 feet. The normal annual air temperature ranges from 37 to 47 degrees Fahrenheit and varies inversely with altitude and latitude. The normal annual pan evaporation ranges from 42 to 60 inches and varies directly with normal annual air temperature. Although not mapped, it is shown that the normal April 1 water content of the snowpack increases from about 5 inches at 7,000 feet to about 11 inches at 9,000 feet. In addition, the year-to-year and within-year variances of some climatic characteristics are illustrated. The standard error of estimate when relating normal annual precipitation to altitude is 17%, which is equivalent to the standard error when relating the average for 5 years of observed record at a site to the long-term mean at the site. Thus, it appears that additional observation points would not improve areal coverage unless the observation sites were continued for 5 years or longer. (USGS)