INTERACTION BETWEEN GROUNDWATER AND SURFACE WATER: QUANTIFYING THE RELATIONSHIP BETWEEN GROUNDWATER DISCHARGE AND WATER TEMPERATURE IN ONEIDA LAKE, NEW YORK. IS WATER TEMPERATURE AN APPROPRIATE PROXY FOR MEASURING GROUNDWATER DISCHARGE?

We measured lakebed temperatures at 500 different locations in a 100 by 125 meter section of a shallow, sandy Central New York lake to assess the validity of using temperature as a proxy for measuring groundwater discharge. The measurements were taken during the late summer of 2006 when the ground water temperature was lower than the surface water; this implies that areas of colder water are correlated with areas of higher ground-water discharge. We also measured ground-water discharge using seepage meters in thirty-one locations to compare temperature to discharge.

We found a clear relationship between ground-water discharge and lakebed temperature. Lakebed temperatures increased with distance from the shoreline, and ground-water discharge rates measured by seepage meters decreased with distance from the shoreline. Our results agree with earlier ground water - lake studies, which found that in homogeneous sediments, ground-water discharge is focused near the shore.

Temperature, when used as a proxy for groundwater discharge, is more time-efficient, cheaper and less environmentally destructive than more traditional methods, such as the use of seepage meters and mini-piezometers. We found a qualitative relationship between groundwater discharge and temperature (low temperature indicates high discharge during the late summer study); however it may be time and site-specific. Additionally, we found no clear quantitative relationship between temperature and discharge. We conclude that temperature is an indicator of discharge yet it may not be a quantitative proxy. Additional research is required to further develop the mathematical relationship between temperature and groundwater discharge.