Water budget and recharge source measurements in a discrete watershed in Central Texas.
The J-17 research site is part of an aquifer-wide study led by Nico Hauwert (City of Austin Watershed Protection Development Review Department and graduate student at the University of Texas, Jackson School of Geological Sciences) to refine the recharge source measurements in karst landscapes in Central Texas. Carbonate aquifers, such as the Edwards Aquifer, typically develop solution cavities as the limestone is dissolved by slightly acidic waters. As a carbonate aquifer matures, more of its surface runoff is directed underground, leaving irregular and poorly defined surface drainages and a very efficient internal drainage system.
The Headquarter Flat Sinkhole Research station is located on the “J-17” City of Austin Water-Quality Protection Land. The sinkhole is 36 acres in size and is a typical internal drainage basin in that no surface drainages contribute to nearby creeks. In late June 2002, Hauwert completed a flow station that measures flow to Headquarter Flat Cave from its major drainage channel to the west. We have been working with Hauwert since 2003 to further describe the hydrologic regime and close the water budget in this sinkhole basin by directly measuring rates of evaporation and transpiration (evapotranspiration, ET) using tower-based eddy covariance.
Collaborators:
City of Austin Water/Wastewater Utility, the Barton Springs/Edwards Aquifer Conservation District, the Texas Cave Management Association
Lady Bird Johnson Wildflower Center .
Mr. Nico Hauwert (Hydrogeologist, Watershed Protection and Development Review Department, City of Austin ) explaining how the flume he installed works (photo by Liang Yang).
Eddy flux tower in oak-juniper savanna on J-17 tract.