Ground-penetrating radar study of the thickness and extent of sediments beneath Silver Lake, Berlin and Meriden, Connecticut

A short-pulse ground-penetrating radar system was used to determine the extent and thickness of organic-rich lake-bottom sediments in Silver Lake in south-central Connecticut. Four mi of ground-penetrating radar profiles were obtained along traverses of the frozen lake during March 1984. The radar waves penetrated 6 inches of snow, 1 ft of ice, an average of 4 to 5 ft of water, and 5 ft of soft organic and inorganic deposits. A large area of the lake bottom is underlain by soft sediment exceeding 5 ft in depth. No radar reflections were obtained from the hard subbottom in these areas because the overlying sediment probably contains large proportions of silt and clay that are relatively impervious to radar. Coring along two radar profile lines confirmed the depths of soft sediment calculated from the radar data. Boring logs around the perimeter of the lake indicate that the eastern side may be underlain by till or poorly-sorted sand and gravel, and that the rest of the lake is probably underlain by fine sands and silts with some discontinuous layers of sand and gravel. (USGS)