A look at one of Austin’s lesser known sinks called Rattlesnake Sink.

Did you know Sunset Valley has a secret sinkhole? Rattlesnake Sink is one of Austin’s lesser known sinkholes which not many people know about. This news article will explain the environmental features of Rattlesnake Sink.

Rattlesnake Sink is a sinkhole located in the Indian Grass Prairie Preserve along Williamson off of Brodie Lane and Home Depot Boulevard. The sinkhole is located along northern edge of the area.  This sinkhole is a sensitive karst feature which is home to a variety of invertebrate species. The sinkhole is composed of two main chambers located approximately 700 feet above sea level. (Ref: https://www.sunsetvalley.org/home/showpublisheddocument/250/637735384638870000)

Rattlesnake Sink is a sinkhole which is a recharge feature for the Edwards Aquifer recharge zone. Rattlesnake Sink is bisected by Williamson Creek, which is composed of Mixed Alluvial Land. Mixed Alluvial Land is comprised of beds of exposed limestone and gravelly alluvium. (Ref: https://sunsetvalleytx.govoffice2.com/vertical/sites/%7B8963FD9D-CEFE-410A-A38B-1611D53E7AA1%7D/uploads/%7BFE34051C-72F3-482E-BF6A-48C94AC66340%7D.PDF)

The geological formation of this sinkhole is quite unique and interesting. Rattlesnake Sink developed as vertical shafts from porous limestone several million years ago. This karst formation is typical of many throughout Central Texas. The karstified limestone acts as an aquifer where water can be stored and later extracted by humans. Dissolution associated with karst development in central Texas limestone has created a complex underground water flow network that includes sinkholes large enough for humans to access. Rainwater travels through the network, controlled by the Balcones fault system, until it reaches the water table. (Ref: https://www.geocaching.com/geocache/GC48Q5D_sunset-valley-is-sinking?guid=007eb7a0-f4c9-47f4-b77d-50cce146b2e3)

However Rattlesnake Sink is not safe to explore because of the presence of rattlesnakes and other wildlife. Rattlesnake Sink is supposedly home to lots of wildlife. Rattlesnake Sink is located in the Edwards Aquifer recharge zone which is an environmentally sensitive area. If there are signs of human activity in the sinkhole, then that means water from the Edwards Aquifer recharge zone would be polluted. 2 million people in Central Texas rely on Edwards Aquifer for drinking water.  

Rattlesnake Sink is located about 20 feet south of Home Depot Boulevard in a shaded area surrounded by trees and shrubbery. Rattlesnake Sink is located at 5886 Brodie Lane, Austin, Texas, US 78745. (Ref: http://www.austinexplorer.com/Locations/MapLocation.aspx?LocationID=18200)