Non-Invasive Time-Lapse Imaging of Rainfall Infiltration Levels in the Sedimentary Soils of Central Panama

Abstract

The economic and commercial worldwide impact of the Panama Canal makes this route one of the most important international maritime routes. The quality of water in communities located near the vicinity of the Canal makes conservation and understanding of water resources a priority. In order to identify the stratigraphy and to understand the infiltration processes caused by the rains in the area of Gamboa between the transition (dry to rainy season) and rainy seasons, a time-lapse electrical resistivity tomography analysis was performed. The results showed two horizons constituted mainly by clay material. The first one composed of clay and accumulation of rocks in some areas and the second, the same clay material with certain level of moisture. About the time-lapse results, the negative percent change of resistivity (between 0 and -46.5%) obtained are associated with the rainfall that reached 19 mm during the last days of the second survey; this fact demonstrates the remarkable contribution of the rains to the groundwater that feed the Panama Canal. Moreover, the positive percent change of resistivity (between 0 and 50%) are linked to artefacts which can be common linked to inversion scheme, electrode array or electrode removal and relocation process.