INVESTIGATION OF SURFACE-GROUNDWATER INTERACTIONS NEAR A MUNICIPAL WELL FIELD IN ZANESVILLE, OHIO

Surface water-groundwater interactions have been studied extensively due to their importance in identifying the means of aquifer and stream recharge and discharge. Water temperature can be a useful tracer to determine groundwater flow paths and relative flow contributions from varying sources. Groundwater extracted from an alluvial sand and gravel aquifer at the Zanesville Municipal Well Field in Zanesville, Ohio displays anomalous temporal and spatial temperature patterns. Groundwater temperatures from water wells (pumped at a depth of ~64 feet) routinely strayed from the mean annual air temperature (11.2°C). Six wells, ranging in distance from 90 ft to 560 ft to the nearby Muskingum River, each had average deviations greater than 3°C from the mean annual air temperature. One well located 115 ft from the river, had an average deviation from mean annual air temperature of 6.0°C, with both the coldest recorded temperature (3.9°C in May, 2015), and warmest temperature (25°C in October, 2001) of any of the six wells surveyed. The well consistently had cool temperatures in the early summer months and warm temperatures in the early winter months. Pumping induced riverbank infiltration is suggested as a cause of this phenomenon. However, temperature fluctuations do not display a consistent dampening effect with distance from the river, and the average groundwater temperature in each well exceeds the mean annual air temperature by 2.4-4.0 °C. Water temperatures measured at the most distal wells are exclusively higher than the mean annual air temperature, suggesting a heat source unrelated to the river.