Profiling experiment of a lake using Ground Penetrating Radar

Great significance of underwater environment was gradually attracting attention and many traditional methods showed obvious shortcomings in underwater exploration, while the ground penetrating radar (GPR), as a new method in this field, performed well in identifying suspended solid and underwater relic. We conducted a GPR survey experiment on a drinking water reservoir to test the applicability of 100 MHz, 200 MHz and 400 MHz frequency antenna in underwater exploration. The experimental results showed that the electromagnetic waves of 100 MHz frequency antenna could penetrate to a greater depth below lakebed than two other antennas especially in water depth over 7 m where 200 MHz frequency antenna barely receipted any signal. But in shoal water less than 4 m, the profiles of 400 MHz frequency antenna presented higher vertical resolution than of 100 MHz. Before the GPR survey, a measurement of the dielectric constant and conductivity of the water was carried out to calculate the attenuation coefficient and velocity of electromagnetic waves in the water. Eventually, the effects of "half hyperbolas" and multiples of GPR were pointed in particular, and the profiling of the lake was given from GPR image. GPR can provide detailed information about underwater stratigraphy and obstructions.