View of the middle stretch of the Dry Frio River as it enters the Balcones Fault zone. In the foreground, the river deserves its name, but in the background the last pools of water are visible. As the river hits the fault zone, the water goes underground through the cracked limestone bedrock. During major flood events, water flows on the surface of the Dry Frio all the way south below the Balcones Escarpment where it joins the larger, more permanent Frio River near Knippa, Texas. Photo by Steve Black.