Grantee Research Project Results

Investigating Surface Water Quality Impacts on Groundwater Quality Under Varying Flow Conditions in the Barton Springs Segment of the Edwards Aquifer, Central Texas

EPA Grant Number: FP917114
Title: Investigating Surface Water Quality Impacts on Groundwater Quality Under Varying Flow Conditions in the Barton Springs Segment of the Edwards Aquifer, Central Texas
Investigators: Wong, Corinne
Institution: The University of Texas at Austin
EPA Project Officer: Packard, Benjamin H
Project Period: August 25, 2010 through August 24, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010) RFA Text | Recipients Lists
Research Category: Fellowship - Water Quality: Hydrogeology and Surface Water , Academic Fellowships

Objective:

It is critical to understand the processes that control groundwater quality, especially in arid regions with a high dependence on groundwater that are managing increasing rates of urban development and aridity associated with climate change. Karst terrains add complexity as solutional features (i.e., caves and sink holes) allow rapid infiltration and subsurface transport of water through the system. This research investigates the hydrological and geochemical dynamics affecting groundwater quality in the Barton Springs segment of the Edwards aquifer (a karst aquifer) in central Texas by investigating the question of how surface water quality impacts groundwater quality under varying rainfall conditions.

Synopsis:

In karst systems, groundwater is especially vulnerable to contamination via surface water. The nature of surface and groundwater interaction is dependent on antecedent moisture conditions, and I work to understand the dynamics of surface and groundwater mixing under varying rainfall conditions in the Barton Springs segment of the Edwards aquifer in central Texas.

Approach:

Surface and groundwater quality will be monitored during base flow and storm conditions for 18 months. Surface water quality will be characterized and correlated to groundwater quality under varying rainfall conditions to quantify: i) the proportion of surface water consisting of groundwater discharge, and ii) impacts of surface water quality on groundwater. Geochemical modeling will be conducted to identify the controls on groundwater quality and understand how these controls vary temporally and in response to climatic variation.

Expected Results:

The expected results from this research include: i) the quantification of the proportion of surface water comprising spring discharge under varying flow conditions; ii) the characterization of surface watersheds under varying antecedent moisture conditions, and evaluation of how these characterizations reflect the degree of watershed urbanization; iii) identifying the controls on groundwater quality under varying antecedent moisture conditions. Groundwater quality is likely more vulnerable to surface water quality during dry antecedent moisture conditions when aquifer levels are insufficient to effectively buffer (i.e., dilute) surface water compositions.

Potential to Further Environmental/Human Health Protection:

Demonstrating the impact of surface water quality on groundwater quality will be useful to water resource managers and law and policy makers as they make decisions regarding the protection of surface water quality in the contributing and recharge zones of the Barton Springs segment of the Edwards aquifer. More specifically, this research will lend insight about the consequences of discharging treated wastewater into surface streams that recharge the Edwards aquifer.

Supplemental Keywords:

groundwater, water quality, nutrients, water management, karst, aquifer, Texas, Edwards aquifer, surface water, Barton Springs,

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.