GEOCHEMICAL ANALYSIS OF SPRING DISCHARGE AT THE TWINSBURG PARK AND NATURE PRESERVE, SUMMIT COUNTY, OHIO

Seven groundwater samples were collected from springs at the base of the east facing McDonald Ledges at Twinsburg Park and Nature Preserve, Summit County, Ohio. The city of Twinsburg is currently developing the site and installing a number of ball fields. The objective of this study was to collect baseline data that will be used to assess the impact of this development on the groundwater resources of the adjacent nature preserve. The springs emerge from the Pennsylvanian, Sharon Sandstone that is overlain by thin deposits of carbonate-rich till. The samples were analyzed for pH, temperature, conductivity, total dissolved solids, major cations, and major anions. The total dissolved solids (TDS) ranged from 51 to 289 with an average of 115 mg/L. These values are considerably less than the average TDS for the Sharon aquifer (436 mg/L). The pH values ranged from 5.33 to 6.89, with an average of 6.02, which is more acidic than the average pH for the Sharon aquifer of 7.0. There is a positive correlation between pH and TDS (R=.83). Four of the samples were classified as calcium-bicarbonate-rich on a piper diagram. The remaining three samples were classified as calcium-sulfate-rich. These classifications are consistent with samples previously collected from the Sharon Aquifer in Summit County. The calcite saturation index (SI) ranged from -4.50 to -.89, indicating all seven samples were undersaturated with respect to calcite. Four springs had a pH less than 6.0, a TDS close to 50 mg/L and average calcite SI of -4.0. The three samples with a TDS greater than 100 mg/L and pH greater than 6 had an average calcite SI of -1.2. As the TDS and pH increase the saturation with respect to calcite increases. Previous studies have shown that TDS and pH values of water samples collected from the Sharon aquifer increase as the thickness of overlying, carbonate-rich, glacial till increases. The springs with the lowest TDS have a pH similar to rainwater. Recharge for these springs was directly into the sandstone and flow was most likely along joints and fractures in the sandstone. Water from the three springs with a higher TDS and pH, flowed through carbonate-rich tills prior to recharging the sandstone aquifer.