Identification Of Down Surface Flow Direction With GPR Method (Ground Penetrating Radar)

Abstract

Estimates of shallow groundwater use GPR (Ground Penetrating Radar) in the
Perum Kenten region with lowland morphology with rock lithology included in
the formation of swamp deposits consisting of mud, mud and sand, the Palembang
city government. The purpose of this GPR measurement is to find out the
subsurface layer and the presence and distribution of groundwater based on
differences in the dielectric constant found in each layer. Dielectric contrast in
rock layers will cause differences in wave velocity and difference in amplitude of
reflection signals. Based on the difference in the dielectric constant which causes
the difference in the amplitude of the reflected signal, the layer passed by the
electromagnetic wave can be identified. Data is obtained from the use of GPR
equipment with an antenna frequency of 250 MHz with depths ranging from 8
meters to 13 meters. Data retrieval is done in clear weather. Measurements with
11 line profiles and varying line lengths are interpreted by geological structures.
From the measurement results there are 2 layers, namely the top layer with a
thickness of 1-2 meters and sand with a thickness of 11-13 meters with a small
dielectric contrast value. Geologically, the sand layer is thought to be a superficial
layer of groundwater, but its potential and distribution resulting from
measurements in this area is relatively low