Chapter 7.2, Page 2 of 4

Hydrogeologic Units

The majority of ground-water withdrawals in the area are from the basin-fill deposits of Tertiary and Quaternary age. These include, in descending order, rock units within the Farisita, Huerfano, Cuchara, and Poison Canyon Formations (Table 7.2-1). The upper Tertiary deposits, described as a salmon-pink basin-fill alluvium consisting of irregularly stratified stream-deposited fine- to coarse-grained sand with pebbles, cobbles, and boulders, are the primary source of water in the Wet Mountain Valley and Huerfano Park. The alluvium is up to 1,200 feet thick.

Table 7.2-1 Hydrogeologic Units of Wet Mountain Valley and Huerfano Park
(Click image to zoom 18KB)

Quaternary deposits in the Wet Mountain Valley consist of terrace gravels, valley fill, and glacial till and outwash. The size of this material ranges from clay to boulders, with considerable variability in aquifer characteristics.

Chapter 7.2, Page 2 of 4