San Antonio River Tributaries

San Antonio River Tributaries. . The San Antonio River Is Formed By Springs that rise to the surface from the Edwards Aquifer north of downtown and by tributaries that flow into the river channel along its winding route. Most of these tributaries in Bexar County are on the west side of the river. The northernmost of these, Olmos Creek, empties into the river near its headwaters. Several creeks that merge west of downtown also feed the river. Martinez Creek empties into the Alazan that, with the Apache, joins San Pedro Creek before its confluence with the river a short distance upstream from here. Other waterways flow into the river below the confluence, including Concepción Creek at this site and Asylum and Piedras (Six-Mile) creeks further to the south. Below the city, Salado Creek enters the river at Southton, the Medina River merges into the channel near Braunig Lake, and Cibolo and Ecleto creeks join the river as it meanders southeasterly. Formed by these many sources, the San Antonio River completes its 240-mile journey when it joins the Guadalupe River near San Antonio Bay and the Gulf of Mexico., Captions , Lower Left: Tributaries play a major role in flooding along the San Antonio River. Work to control this flooding has included construction of a flood retention dam across Olmos Creek in 1926 (left), widening and deepening creek channels on the city's west side during the 1960s and 1970s (center), and the San Pedro Creek flood control tunnel (right). , Upper Right: The San Antonio River Channel Improvements Project was authorized in 1951. As part of this project, the San Antonio River Authority and U.S. Army Corps of Engineers greatly increased the flood-carrying capacity of the city's west side creeks. Because this work also removed habitat and vegetation, planning is now underway to restore the ecosystem along all the creeks including San Pedro, seen here. , Lower Right: The flood capacity of the San Antonio River channel below its confluence with San Pedro Creek is four times its upstream capacity in order to contain water from both the river and its tributaries in times of heavy rainfall. This map illustrates the tributaries that flow into the San Antonio River on the west side of downtown., Courtesy: Lewis F. Fisher, San Antonio , Courtesy: Light Collection, University of Texas at San Antonio Libraries Special Collections , Courtesy: San Antonio River Authority , Photo: Maria Watson Pfeiffer, San Antonio , Courtesy: San Antonio River Authority