Climate and Water
An area’s climatic conditions will ultimately control its ground-water resources because the source of ground water is infiltration of precipitation. Colorado’s location, far inland from any ocean, and its variable topography greatly influence weather patterns producing a semiarid climate with hot summers and cold winters. These climatic conditions produce a mean annual statewide precipitation of 17 inches. On average, 81 percent of the precipitation that falls on the land surface is lost through evapotranspiration producing a water balance deficit over most of the state, with the exception of the higher mountainous regions (Figure 1.3). While the amount of water recharged to a local aquifer is dependent upon climatic conditions, land surface characteristics, and aquifer hydraulic parameters, the delicate water balance in Colorado limits the water available for long-term storage from fractions to a few inches per year. Given these low recharge rates, it is readily seen why ground-water resources should be considered a finite resource.
Thunderstorms on the eastern plains, while typically intense,
provide little recharge to ground water.