Report 331 by Barbara E. Beynon, Geologist | July 1991

• Report 331 - Ground-Water Quality Monitoring of the Trinity Aquifer in the Vicinity of Erath County (pdf - 4.04MB)
• Figure 2 (pdf - 1.80MB) - Geologic Map
• Figure 4 (pdf - 1.00MB) - Well Location map
• Figure 6 (pdf - 1.00MB) - Map of the Iron Concentration in the Twin Mountains Formation in the study area
• Figure 7 (pdf - 1.10MB) - Map of the Nitrate Concentration in the Twin Mountains Formation in the study area
• Figure 8 (pdf - 1.00MB) - Map of the Alpha Radiation Concentration in the Twin Mountains Formation in the study area
• Figure 9 (pdf - 0.98MB) - Changes in Historical Water Quality