GPR Survey for Bathymetric Mapping of Ang Kaew Water Reservoir, Chiang Mai University, Thailand

Abstract

Summary Preliminary bathymetric mapping using GPR survey has been conducted on Ang Kaew reservoir located in Chiang Mai University main campus, Thailand. The GPR survey was done on an inflatable boat by the pulseEKKO PRO GPR system using 50MHz antenna with an integrated GPS system for data acquisition navigation. We acquired 3 GPR survey lines across Ang Kaew reservoir with a length of 70, 320, and 270 m, respectively. From the processed GPR profiles, the water depths were varied and could be deeper than 7 m at the crossing of the long profiles close to the front dam of the reservoir. Other reflections at the end of each GPR profile are due to the reflected signal from the trees nearby. The GPR signal could only penetrate with a clear signal upto depth of approximately 5 m using 50MHz antenna. The sub-bottom sediment layer could not be seen on the GPR profiles even in the shallow water zone. However, more GPR surveys with different frequencies should be performed on the shallow zone in the western side of the reservoir where an accumulation of sediments is expected.