INFLUENCE OF PRECIPITATION PATTERNS ON SURFACE WATER AND GROUNDWATER IN THE SANDY CREEK WATERSHED, NEW YORK

Predictions for future climate in the Northeastern United States is for greater total precipitation but more and longer drought periods. This equates to fewer but larger precipitation events. In an effort to better understand the response of small watersheds to drier and wetter than normal precipitation events, a study is underway on the Sandy Creek watershed. The Sandy Creek watershed drains a rural portion of the Lake Ontario lake plain. During the summer of 2013, the 7-day running average discharge was correlated with the 7-day running average precipitation and found to be significant using the Spearman’s rho test. During the summer of 2014, the study focused on the eastern branch of the watershed to avoid complications with seiche from Lake Ontario. The 2014 study also included monitoring of a the local shallow water table aquifer, and qualitative evaluation of the 2013 hydrograph showed some relationships between precipitation events and baseflow. To date, results of the 2014 data show a correlation between precipitation and discharge. Monitoring a conductivity in both surface and groundwater show that during a long drier than normal period in late spring, groundwater conductivity steadily decreased from 980 μS cm^-1 to 840 μS cm^-1, approaching the upper limit of surface water values which vary within a range of 460 to 760 μS cm^-1. As expected, groundwater contributions to stream discharge increase during the drier than normal periods, but it remains unclear as to the impact of the frequency of rain events to stream discharge and groundwater recharge.