COMPARING THE EFFECTIVENESS OF DIFFERENT METHODS USED TO DETERMINE GROUNDWATER – STREAM INTERACTIONS IN AN ALLUVIAL AQUIFER IN CLINTON, NY

Determining the spatial and temporal exchange of groundwater and surface water can be done using many different methods. However, constraints from equipment costs and lack of technical expertise can make quantifying these interactions difficult. Our project is focused on analyzing five different methods to determine groundwater - surface water interactions during times of groundwater pumping and non-pumping: stream discharge measurements, vertical head gradients from minipiezometers installed into the streambed, comparisons of short-term pumping-induced fluctuations in major ions and stable isotopes in the stream and groundwater, streambed temperature measurements that use heat transport models to calculate vertical flow, and numerical modeling. We are evaluating the interaction between groundwater and surface water in an alluvial aquifer with an adjacent stream in Clinton, NY. Each method demonstrated that pumping induces infiltration of stream water into the aquifer, but each method resulted in different spatial and temporal values of groundwater – surface water exchange. Thus, our goal is to evaluate the different approaches used in our study for understanding groundwater - surface water interactions and focus on the method's balance between cost and accuracy, required technical expertise, and equipment needs.