THE HYDROGEOLOGY AND GEOCHEMISTRY OF LIBERTY PARK, TWINSBURG, OHIO, A BASELINE STUDY

Pond Brook, a channelized stream, drains the wetlands in Liberty Park located in Twinsburg, Ohio. The Metro Parks serving Summit County has plans to remediate the wetlands by restoring Pond Brook to its natural state. The objective of this study is to collect background data prior to restoration. The lower Pennsylvanian-age Sharon Conglomerate/Sandstone crops out in a pair of scenic ledges located in the western portion of the park. The study area overlies a north-south trending buried bedrock valley containing at least 125 m of Pleistocene sediments; the upper 18 m, of which, represent three late Wisconsinan glacial advances. Late glacial meltwater “drowned” ground moraine of the Hiram advance and deposited low-lying impermeable clays that underlie the wetlands. Water samples were collected from streams, piezometers, and natural springs and seeps within the park. Samples were analyzed for pH, temperature, conductivity, dissolved oxygen, total dissolved solids, major cations and major anions. The gradient of Pond Brook is less than 0.9 m/km, but its velocity was too low to be measured with a Pygmy low-flow meter. Dissolved oxygen and pH values ranged from 4.25 to 12.95 mg/L and 6.09 to 8.59, respectively. Conductivities of the springs ranged from 0.11 to 0.26 mS, whereas conductivities of streams and near-surface ground water ranged from 0.40 to 1.42 mS. Calculated total dissolved solids of spring water varied between 68 to 167 mg/L; calculated total dissolved solids values in stream discharge and shallow groundwater samples ranged from 252 to 920 mg/L. Groundwater samples were calcium-bicarbonate types, but stream discharge samples were sodium-bicarbonate types. Spring samples ranged from calcium-bicarbonate to calcium-sulfate types. All spring samples were undersaturated with respect to calcite, whereas the stream and groundwater samples were variable. Time-series analyses of groundwater levels and stream stages indicate water levels respond rapidly to increased precipitation. Water levels then decrease very quickly because Pond Brook is capable of removing water from the park efficiently.