Interpretation of Distribution of Ancient Rivers in Singapore Using 3D Geological Model

The Kallang formation alluvial member (Ka) in Singapore was mainly deposited in river channels during middle or late Holocene. It carries information regarding the changes in the distribution of river channels. Identifying the distribution of rivers is important as the presence of rivers are usually associated with weak or complicated geotechnical properties of the soil deposits below. However, some ancient rivers are buried beneath the superficial formation layers and cannot be directly observed in the contemporary era. The objectives of this paper are to present a method to identify the distribution of rivers using a 3D geological model and use it to investigate the distribution of ancient rivers in Singapore. A 3D geological model in the Rochor River area of Singapore was firstly established using borehole data. The procedure adopted for the 3D geological modelling involved in geological data preparation, cross-section, and fence diagram creation, and 3D model construction. The 3D model was then used to identify the distribution of the ancient river channels with the validation of the deposited Ka. The interpretation results indicate that there are ancient rivers existed underneath the Rochor River area as well as a comparison of rivers in the ancient and present time is made.