1970s. In recent years, use of GPR has increased in hydrogeological investigations, since
the presence or absence of water dominates GPR responses. Use of radiowaves for
groundwater was first reported by El Said (1953). The same fundamental concepts used for
subsurface lunar investigations (Annan, 1973) underpin modern GPR concepts. Annan
(2002) provides a brief history of GPR over the past 50 years; the GPR conference …