43 Environmental Geoscience and Hydrogeology

Wednesday, 14 March 2007
8:15 AM - 12:00 PM

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?

Paper number: 43-12
Program: Technical Sessions
Time: 11:35 AM – 11:55 AM

Authors

Abstract

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.