Accuracy Assessment of Satellite-Derived Bathymetry From Band Ratio Algoritm Around an Earth Dam

Abstract

Long-term changes in the bathymetry of a reservoir using satellite-derived bathymetry (SDB) from Landsat 8 Operational Land Imager (OLI) imagery was investigated. The reservoir's initial design in 1973 included a specified spatial extent of 570,000 square meters, a maximum depth of 8.5 meters, and a water storage capacity of 2,600,000 cubic meters. However, sedimentation over time gradually reduced the storage capacity and depth, leading to a dredging operation in 2014 to restore some of its original features. Focusing on the post-dredging period, the study compares the results to the reservoir's initial design plan. Results indicate a consistent marginal decline in the spatial extent, with an overall decrease of 26.10% from impoundment to the present. Satellite-derived depths showed a clear downward trend, representing a significant reduction of 68.11% over half a century. The volume capacity exhibited a consistent decline, with an overall loss of 71.98% from impoundment to the present. The findings highlight the continuous challenges posed by sedimentation, underscoring the need for ongoing monitoring and effective management strategies to maintain the reservoir's functionality and capacity as a crucial water resource. Furthermore, the study establishes a strong positive correlation (R² = 0.99) between storage volume capacity and derived depth values. This correlation validates the reliability and accuracy of the depth estimation method used, offering potential utility for reservoir management and water resource planning. Overall, the research emphasizes the importance of SDB for monitoring long-term changes in bathymetry and highlights the significance of effective sedimentation management to ensure sustainable reservoir utilization.