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Keep wimberley Beautiful

Wimberley Karst Beauty

A glimpse at a karst feature.

This week our guest writer, Tom Jones, will help us understand the karst landscape under our feet that determines the natural beauty of Wimberley.

Karst is a topography formed by rainfall entering into and dissolving the abundant limestone formations. This type of karst feature can be seen in the numerous examples of honeycomb limestone used to landscape yards.

Sinkholes, caves and honeycomb limestone are karst features formed by acidic rainwater slowly dissolving the limestone layers. As rain falls through the atmosphere it picks up carbon dioxide (CO2) and becomes acidic. Typically rainfall has a pH of 5.5. For comparison, tap water has a neutral pH of 7 and Pepsi’s pH is 2. Over thousands or millions of years, rainwater has continued to fall on and enter into the land surface via the numerous faults and fissures. The acidic water slowly dissolved the limestone causing the cracks to enlarge and the faults to widen.

The local valleys are formed by the erosive action of the Blanco River and Cypress Creek. Ranch Road 2325 follows the ridge between the Blanco River and Cypress Creek thus offering overviews of these expansive valleys. The other important feature of the area is the high concentration of faults that stretch across the valley bisecting both rivers and hills.

The karst region in the Wimberley Valley does influence land use and water resources. Potential impacts include sinkhole collapse, increased groundwater contamination risk, and an unpredictable water supply. The honeycomb limestone is effective in quickly moving ground water through the aquifers which can result in reduced water availability for this region. Decreasing stream flows may also impact the ecology of the Hill Country. Karst gives this region its iconic Hill Country look and enables the numerous creeks and springs that attract people to live and visit the Wimberley Valley.

Written by Tom Jones, Hays County Master Naturalist

Wimberley View

P.O. Box 49
Wimberley, TX 78676
Phone: 512-847-2202
Fax: 512-847-9054