GROUNDWATER-SURFACE WATER INTERACTIONS OF TWO WETLANDS IN LIBERTY PARK, TWINSBURG, OHIO

The hydrology of Liberty Park, located on the Glaciated Allegheny Plateau in Twinsburg, Ohio was investigated. Land use practices such as clear cutting, draining for agriculture and suburban development significantly changed the hydrology of the area. Pond Brook, the main tributary in the park, was channelized and dredged into a 30-40 ft wide, straight stream for the purpose of removing water from the system quickly and to prevent flooding of a nearby subdivision. Wetlands within the park range from high quality wetlands with threatened and endangered plant species to modified, low quality wetlands overrun by invasive species. Continuous water level data loggers were installed in Pond Brook and monitoring wells in 2 wetlands. Hydrographs show that after a precipitation event, there is an instant rise in the water level of Pond Brook, followed by a rapid decrease as the stream returns to baseflow over a period of 2 to 5 days. Water level in the modified, low quality wetland exhibited rapid fluctuations. The average depth to water was 31 cm with a range of 70 cm, from 23 cm above ground surface to 47 cm below ground surface. The shape of the hydrographs for Pond Brook, and the modified wetland mirror each other, which suggest this wetland is hydrologically connected to Pond Brook. Analysis of the subsurface geology indicates the wetland is underlain by impermeable clay deposits, and there is no evidence of a permeable, sandy layer at depth. Movement of water between the modified wetland and Pond Brook is most likely along fractures within the glacial clay deposits. The depth to water in the high-quality wetland averaged 0.4 cm and ranged 66 cm from 19 cm above ground surface to 48 cm below ground surface. The water level fluctuations in this wetland were more gradual and reflect seasonal changes in ground-water inputs. The high quality wetland is hydrologically isolated from Pond Brook and receives the bulk of its water input from spring discharges at the base of nearby sandstone ledges.