Comanche Springs are a group of karst springs that are currently accessible for exploration because excessive groundwater pumping has significantly lowered the regional water table. Between 1922-1947 the springs maintained an average discharge of 1,200 L/s, but discharge decreased when large-scale pumping began, and flow ceased in 1962. Since that time the springs have flowed only twice following periods of sustained major rainfall.

About half of the known 1.2 km of passages have been surveyed. They are highly joint controlled and occur along three main levels about 3 m, 6 m, and 10-13 m below the entrance. The 3-m and 6-m levels often interconnect along common fractures.

These passages average I m wide by 1-2 m high, and they make up most of the cave's explored length. In at least five locations they cross over pits that drop to the water table. Submerged passages up to 3 m in diameter lead off from these pits and constitute the cave's lower level.

The springs developed as outlets for water from the Edwards-Trinity (Plateau) Aquifer into the Comanche Creek Valley. The original springs were probably 13 m lower m elevation and were the downstream end of the large submerged passages. Sedimentation during the Pleistocene filled the valley, plugging those openings and forcing their water to develop the modern, higher passages and spring outlets.

Bibliography:
Brune, G. 1981. The springs of Texas, vol. 1.
Branch-Smith, Inc., Fort Worth, Texas, 566 pp.
Veni, George, and Associates. 1991. Delineation and preliminary hydrogeologic investigation of the Diamond Y Spring, Pecos County, Texas.
Unpublished repoI-t for the Texas Nature Conservancy, Illpp.