Cibolo Creek is a stream in South Central Texas that runs approximately from its source at Turkey Knob (in the Texas Hill Country) near Boerne, Texas, to its confluence with the San Antonio River in Karnes County. The creek is a tributary of the San Antonio River, at the easternmost part of its watershed.
The stream is used for both recreational and cartographic purposes, serving as the eastern boundary of Bexar County, Texas. A wide variety of fish and other wildlife are known to occupy the waters, and several parks have been established along its banks, including Cibolo Nature Center, Boerne City Park and Jackson Nature Center. Additionally, numerous human settlements have been founded on the creek, such as Boerne, Fair Oaks Ranch, San Antonio, Bulverde, Bracken, Selma, Schertz, Universal City, Cibolo, Zuehl, New Berlin, La Vernia, Cestohowa, Kosciusko, Sutherland Springs and Panna Maria.
Course
Cibolo Creek rises in the Texas Hill Country northwest of Boerne in Kendall County, Texas. Every second, approximately of water pass through on its southeastern journey to the San Antonio River. It has been judged as a "scenic" and "picturesque" stream, especially in the upper reaches, as steady flows travel through deep canyons and rocky flats to form falls. Just ahead of its entry into Boerne, the stream is dammed to form Boerne City Lake, which provides drinking water for the town's residents. In Boerne, the creek flows through the center of town before reaching the Cibolo Nature Center, noted for its shores lined with bald cypress trees. East of the nature center, the Cibolo Canyonlands begin, which features even deeper canyons and direct groundwater recharge. Part of this area is protected by the University of Texas at San Antonio for environmental research purposes.
Further downstream, the creek passes through Fair Oaks Ranch and Bulverde. The steady flow begins to dissipate in certain areas as it approaches Camp Bullis in northern San Antonio, leaving dry patches that reveal a rocky bottom. Such dry patches continue as it heads east, forming the boundary between Bexar and Comal Counties. Steady flows pick up on the boundary between Bexar and Guadalupe Counties, passing through Randolph Air Force Base.
At its lower reaches, the terrain grows flatter and less rocky, supporting oak, mesquite and juniper. As it meanders through Wilson and Karnes Counties, passing Zuehl, New Berlin, La Vernia, Sutherland Springs, and Cestohowa, Cibolo Creek meets with the San Antonio River near the ghost town of Helena.
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 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 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 long stream with a Mesquite tree-supporting bed of clay and sandy loam, located near Windcrest in eastern Bexar County; and Santa Clara Creek, long and Elm Creek, long, both streams in Guadalupe County near New Berlin that supports conifers along their shores. Additional tributaries include Alum Creek, and Elm Creek.