Define the Working of Ground Penetrating Radar?
Ground penetrating radars (GPR) and low frequency sound are also used in scour survey. These are good in shallow water but not very effective in salty, brackish water. GPR survey system transmits radio frequency electromagnetic pulses into the water and bed sediments and receives energy reflected back from surface and sub surface reflectors.
The reflectors can be any sub surface contact between water and geological material or geological materials with different physical and material properties. Man made materials such as concrete and steel also can be a sub surface reflector. All depths to existing and new scour holes and bed bottom and sub-bed bottom reflectors are approximate. These depths are based upon estimated ground penetrating radar two way travel time for water, saturated sands, fill and bed rock.