Satellite-derived bathymetry in the turbid and shallow waters of the bandama estuary (Cote D’Ivoire) using a landsat 7 etm+ multispectral image

In shallow waters, traditional bathymetric methods such as acoustic and LIDAR (Light Detection And Ranging) systems are accurate; however they are constrained by high operational costs, logistic difficulties and limited spatial coverage. Shallow water depth estimation using passive remote-sensing method is an attractive alternative as it provides a time- and cost-effective solution to water depths estimation. The paper highlights the application of incorporating satellite remote sensing techniques to extract bathymetry information from the freely downloadable Landsat-7 ETM+ satellite images. This paper compares the two of the most commonly used methods, Stumpf and Lyzenga to estimate water column depth in Bandama estuary.The Lyzenga’s model achieved root mean square error (RMSE) of 1.91 m, while Stumpf’s model delivered RMSE of 3.09 m. The absolute differences between known depths and estimated depths (MAE)was 1.44 m concerning Lyzenga’s model, whilst Stumpf’s model obtained MAE of 2.59 m.In general, the Lyzenga’s model is more robust than the Stumpf’s model in the study area. The geographical distributions of model residuals are mapped as a basis for comparing the performance of the bathymetric models. The map of model residuals revealed a tendency for negative residuals in shallower areas and positive residuals in deeper areas.