Frequency Domain Electromagnetic (FDEM) Geophysical Data Collected near Lake Placid, NY

This data release contains frequency domain electromagnetic (FDEM) data collected during discrete times between July 2019 to October 2022 near Lake Placid, NY as part of a multi-method effort to monitor the effects of different road salt treatments on groundwater and the surrounding surface water (West Branch Ausable River). The FDEM instrument used was a Geophex GEM-2; a broadband sensor that measures the bulk conductivity and magnetic susceptibility of the subsurface down to approximately 5 meters (16.4 feet) depth. The instrument is hand carried by a single operator and data are collected at walking speeds. Data were repeatedly collected during each campaign at the three sites nicknamed for the planned road salt treatment at the site (i.e., “abrasives", "low salt", and "control"). Specifically, "control" refers to normal levels of salt applied in winter, "low salt" refers to a planned reduction in the amount of salt, and "abrasives" refers to an alternative sand/salt mix treatment. Limited data were also collected in August and October 2020 at the High Falls Gorge parking area ("high falls") and an area with an upgradient (relative to the road) spring ("springs"), respectively. All data were collected at 6 frequencies ranging from approximately 3KHz to 93KHz. Lower frequencies are sensitive to larger volumes of subsurface material, and therefore, have a deeper depth of investigation than higher frequencies (at the cost of an overall lower signal/noise ratio relative to higher frequencies). Data were collected in a horizontal coplanar orientation at walking speeds with the GEM-2 ~1 meter above ground surface. Surveys at each site include discrete sections of roadway (NY Route 86 and NY Route 73) and areas upgradient and downgradient from the roads. These data are in two zipped folders: (1) raw instrument data from each site with the associated time of collection (Raw.zip), and (2) compiled processed data converted to apparent electrical conductivity and magnetic susceptibility (Processed.zip).