Update of Barton Springs Water Quality Data Analysis - Austin, Texas
Barton Springs, the major discharge point for the Barton Springs segment of the Edwards Aquifer, is primary habitat for the endangered Barton Springs salamander (Eurycea sosorum), supplies a portion of Austin’s drinking water, provides winter and drought baseflow to the Colorado River downstream, and is an important recreational resource. Significant time trends in Barton Springs have not been previously identified. However, the passage of time, continuing development, and increased data collection efforts combined with recognition of the importance of variable recharge/discharge conditions has led to additional data analysis. The current analysis of long term water quality records (1975-1999) from Barton Springs indicates statistically significant changes in water quality potentially related to watershed urbanization. Increasing specific conductance, sulfate, turbidity, and total organic carbon trends were noted to be significant. A decreasing trend in dissolved oxygen concentrations was also significant in Barton Springs. Significant trends were not noted in other parameters that are commonly considered pollutants, such as nutrients and total suspended solids. However, when older, less verifiable data is included in the analysis, a long term increase in nitrate nitrogen is statistically significant. Constraints associated with using this type of data analysis for future predictions are discussed.