VALIDATING THE REMOTE SENSING APPROACH TO THE BATHYMETRIC SURVEY OF TAGWAI DAM

Abstract

Remotely sensed image data are considered attractive for bathymetry applications as they provide a timely and less cost-effective solution to ocean depth estimation. The research uses a remote sensing technique to present an estimate of the depth (bathymetric survey) of Tagwai Dam. In this research work, sentinel-1 image data was used, having undergone the pre-processing stages, to derive the depth, and three spectral bands, blue spectrum (450-520nm), green spectrum (530-590nm) and NIR spectrum (850-880nm) were utilized to carry out this task. Stumpf’s (Sfs) Model of depth estimation was implored. The highest depth recorded by the Sf’s algorithm was 17.352m as against the highest depth recorded by echo (Ec) sounding equipment 20.800m, which happens to be the referenced observation. Statistical tools were used to compute the Root Mean Square Error (RMSE), the standard error of the estimate (SEE), and the Correlation Analyses Index (CAI) between the Sf’s algorithm and the Ec sounder. The RMSE incurred was 3.324, the SEE was 0.4901, while the correlation analyses index R was about 95%, which shows a high level of closeness between both approaches. However, the results also indicate that the rate of growth of sediment accumulation over time is alarming, as it gradually reduces the capacity of the dam. Hence, the authority involved should, as a matter of urgency, carry out an overhaul of sediment removal to preserve the life span of the dam.