Cibolo Creek - Watershed

Watershed

The drainage basin of Cibolo Creek is located in the lower reaches of the Cretaceous Glen Rose Formation along the southeastern edge of the Edwards Plateau. Many springs located in the upper and middle reaches of the watershed engage in karst activity in the limestone prevalent below the surface, forming such caves as Cascade Caverns and Natural Bridge Caverns. An exchange occurs between the stream and these numerous underground springs that serve as a recharge for the Edwards-Trinity aquifer system. This system provides drinking water for millions of people in the surrounding area. Near the recharge zone, distributaries of the creek have carved deep canyons in the landscape of the Texas Hill Country, forming what is known as the Cibolo Canyonlands. The Cibolo Nature Center claims 1,300 acres (5.3 km2; 2.0 sq mi) of the watershed, to protect the water quality from the hazards of rapid development and population growth.

Several streams serve as distributaries and tributaries of Cibolo Creek, and are included in the watershed. Balcones Creek, a 13 miles (21 km) long stream that rises in Bandera County and acts as the boundary between Bexar and Kendall Counties, is a main tributary of Cibolo Creek that converges at the meeting of Bexar, Kendall and Bandera Counties. Tributaries in the lower watershed include Martinez Creek, a 16 miles (26 km) long stream with a Mesquite tree-supporting bed of clay and sandy loam, located near Windcrest in eastern Bexar County; and Santa Clara Creek, 19.5 miles (31.4 km) long and Elm Creek, 14 miles (23 km) long, both streams in Guadalupe County near New Berlin that supports conifers along their shores.