Evaluating the Impact of Brush Clearing on Recharge to a Karst AquiferEPA Grant Number: F07B20468
Title: Evaluating the Impact of Brush Clearing on Recharge to a Karst Aquifer
Investigators: Wong, Corinne
Institution: The University of Texas at Austin
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: January 1, 2007 through January 1, 2009
RFA: STAR Graduate Fellowships (2007) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Water Chemistry/Hydrology , Water and Watersheds
This project will evaluate hydrologic changes in a cave directly below land that is being cleared of brush. Brush removal to increase recharge to underlying aquifers is a common land management practice in central Texas. However, the effectiveness of such practice is still in question. The objective is to evaluate changes in hydrology in a cave directly below land being cleared by comparing drip rate and drip water chemistry before and after brush clearing.
This study will compare the drip rates and drip water chemistry following brush removal to three years of baseline data that was collected from 2004-2007. The brush is currently being removed using power tools. The cave drip sites will continue to be monitored on a monthly basis following the brush removal through the fall and spring rainy seasons of 2007 and 2008. Drip rates are currently being monitored continuously at three sites using tipping buckets and Onset Micro Stations. Relative humidity, CO2, and water samples will continue to be collected on a monthly interval at all of six sites. Monthly water samples will continue to be analyzed for cations, anions, alkalinity and Sr isotopes in The University of Texas departmental labs. Data will be analyzed for significant differences between drip rate and drip water chemistry.
My hypothesis is that brush removal will increase recharge, and this will be reflected in drip rate and drip water chemistry in the cave below. The results from this study should contribute to the understanding of how environmental variables affect karst hydrology. This study will document how drip rates and drip water chemistry change with the removal of vegetation, and contribute to our understanding of the efficiency of brush removal as a land management practice. The results will also provide an analogue for how changes in vegetation patterns alter karst hydrology and contribute to our understanding of modern karst systems. Understanding the modern karst systems leads to better interpretations of past karst systems preserved in speleothems, which are currently being used in reconstructions of paleoclimate.